/* ========================================
   家庭学习乐园 - 现代UI样式表 v2.0
   设计系统：紫靛蓝主题 · 精致 · 亲和
   ======================================== */

/* === 设计令牌 === */
:root {
  /* 主色 - 靛蓝 → 紫 */
  --primary: #4F46E5;
  --primary-light: #818CF8;
  --primary-lighter: #C7D2FE;
  --primary-dark: #3730A3;
  --primary-bg: #EEF2FF;

  /* 渐变色 */
  --gradient-primary: linear-gradient(135deg, #4F46E5 0%, #7C3AED 100%);
  --gradient-warm: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  --gradient-card-1: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  --gradient-card-2: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
  --gradient-card-3: linear-gradient(135deg, #4facfe 0%, #00f2fe 100%);
  --gradient-card-4: linear-gradient(135deg, #43e97b 0%, #38f9d7 100%);

  /* 功能色 */
  --success: #10B981;
  --success-bg: #D1FAE5;
  --success-text: #065F46;
  --warning: #F59E0B;
  --warning-bg: #FEF3C7;
  --warning-text: #92400E;
  --danger: #EF4444;
  --danger-bg: #FEE2E2;
  --danger-text: #991B1B;
  --info: #3B82F6;
  --info-bg: #DBEAFE;
  --info-text: #1D4ED8;

  /* 中性色 */
  --bg: #F0F4FF;
  --bg-alt: #F8FAFC;
  --card-bg: #FFFFFF;
  --text: #1F2937;
  --text-secondary: #4B5563;
  --text-light: #6B7280;
  --text-muted: #9CA3AF;
  --border: #E5E7EB;
  --border-light: #F3F4F6;

  /* 圆角 */
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;
  --radius-xl: 20px;
  --radius-full: 9999px;

  /* 阴影 */
  --shadow-sm: 0 1px 3px rgba(0,0,0,0.06), 0 1px 2px rgba(0,0,0,0.04);
  --shadow-md: 0 4px 12px rgba(0,0,0,0.06), 0 2px 4px rgba(0,0,0,0.04);
  --shadow-lg: 0 8px 24px rgba(0,0,0,0.08), 0 4px 8px rgba(0,0,0,0.04);
  --shadow-xl: 0 12px 40px rgba(0,0,0,0.1), 0 6px 12px rgba(0,0,0,0.05);
  --shadow-glow: 0 4px 20px rgba(79,70,229,0.2);

  /* 间距系统 (4px base) */
  --space-1: 4px;
  --space-2: 8px;
  --space-3: 12px;
  --space-4: 16px;
  --space-5: 20px;
  --space-6: 24px;
  --space-8: 32px;
  --space-10: 40px;
  --space-12: 48px;

  /* 过渡 */
  --transition-fast: 0.15s ease;
  --transition-base: 0.2s ease;
  --transition-slow: 0.3s cubic-bezier(0.4, 0, 0.2, 1);

  /* 字体 */
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans SC", sans-serif;
  --font-emoji: "Apple Color Emoji", "Segoe UI Emoji", "Noto Color Emoji", "EmojiOne Color", "Android Emoji", emoji;
  --font-mono: "SF Mono", "Fira Code", "Consolas", monospace;
  --font-kai: "楷体", "KaiTi", "STKaiti", "Noto Serif SC", serif;
}

/* === Reset === */
*, *::before, *::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-sans), var(--font-emoji);
  background: var(--bg);
  background-image: radial-gradient(ellipse at 10% 20%, rgba(79,70,229,0.04) 0%, transparent 50%),
                    radial-gradient(ellipse at 90% 80%, rgba(124,58,237,0.04) 0%, transparent 50%);
  color: var(--text);
  min-height: 100vh;
  line-height: 1.6;
  overflow-x: hidden;
  -webkit-tap-highlight-color: transparent;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* Emoji 回退强制 */
.emoji, .subject-icon, .nav-icon, .avatar, .rank-avatar,
.login-logo, .result-emoji, .memory-card-icon, .sq-card-icon,
.mode-icon, [class*="icon"], [class*="emoji"] {
  font-family: var(--font-emoji);
}

/* === 页面切换 === */
.page { display: none; }
.page.active { display: block; animation: pageIn 0.35s ease-out; }

@keyframes pageIn {
  from { opacity: 0; transform: translateY(8px); }
  to { opacity: 1; transform: translateY(0); }
}

/* === 登录页（v3 儿童教育风：渐变+漂浮光斑+毛玻璃） === */
.login-container {
  min-height: 100dvh;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 2rem 1.5rem;
  background: linear-gradient(160deg, #4F46E5 0%, #6D28D9 45%, #7C3AED 78%, #A855F7 100%);
  position: relative;
  overflow: hidden;
}

/* 漂浮光斑与星星（纯装饰） */
.login-decor {
  position: absolute;
  inset: 0;
  pointer-events: none;
  z-index: 0;
}
.blob {
  position: absolute;
  border-radius: 50%;
  animation: blobFloat 13s ease-in-out infinite;
}
.blob-1 {
  width: 230px; height: 230px;
  top: -70px; left: -90px;
  background: radial-gradient(circle, rgba(255,255,255,0.22) 0%, transparent 65%);
}
.blob-2 {
  width: 190px; height: 190px;
  bottom: 12%; right: -80px;
  background: radial-gradient(circle, rgba(196,181,253,0.32) 0%, transparent 65%);
  animation-delay: -4.5s;
}
.blob-3 {
  width: 140px; height: 140px;
  top: 40%; left: -60px;
  background: radial-gradient(circle, rgba(255,255,255,0.16) 0%, transparent 65%);
  animation-delay: -8.5s;
}
.twinkle {
  position: absolute;
  color: rgba(255,255,255,0.9);
  font-size: 15px;
  animation: twinkle 3.2s ease-in-out infinite;
  text-shadow: 0 0 14px rgba(255,255,255,0.9);
}
.tw-1 { top: 15%; left: 22%; }
.tw-2 { top: 30%; right: 16%; font-size: 12px; animation-delay: -1.1s; }
.tw-3 { bottom: 24%; left: 15%; font-size: 11px; animation-delay: -1.7s; }
.tw-4 { bottom: 32%; right: 24%; font-size: 14px; animation-delay: -2.3s; }
.tw-5 { top: 8%; right: 36%; font-size: 10px; animation-delay: -0.6s; }

@keyframes blobFloat {
  0%, 100% { transform: translate(0, 0) scale(1); }
  33% { transform: translate(20px, -26px) scale(1.07); }
  66% { transform: translate(-16px, 18px) scale(0.95); }
}
@keyframes twinkle {
  0%, 100% { opacity: 0.25; transform: scale(0.8) rotate(0deg); }
  50% { opacity: 1; transform: scale(1.2) rotate(25deg); }
}

.login-brand {
  position: relative;
  z-index: 1;
  text-align: center;
  margin-bottom: 2.2rem;
}

.login-logo {
  font-size: 3.6rem;
  font-family: var(--font-emoji);
  margin-bottom: 0.6rem;
  display: inline-block;
  animation: logoFloat 3.2s ease-in-out infinite;
  filter: drop-shadow(0 10px 20px rgba(0,0,0,0.28));
}

@keyframes logoFloat {
  0%, 100% { transform: translateY(0) rotate(-3deg); }
  50% { transform: translateY(-10px) rotate(3deg); }
}

.login-title {
  font-size: 2.1rem;
  font-weight: 800;
  letter-spacing: 0.05em;
  margin-bottom: 0.3rem;
  background: linear-gradient(180deg, #FFFFFF 15%, #EDE9FE 60%, #DDD6FE 100%);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  color: transparent;
  filter: drop-shadow(0 4px 14px rgba(76, 29, 149, 0.45));
}

.login-subtitle {
  color: rgba(255,255,255,0.92);
  margin-bottom: 0;
  font-size: 1.05rem;
  font-weight: 500;
  letter-spacing: 0.08em;
  text-shadow: 0 2px 10px rgba(0,0,0,0.18);
}

/* 毛玻璃卡片 */
.login-card {
  background: rgba(255,255,255,0.16);
  backdrop-filter: blur(18px) saturate(1.4);
  -webkit-backdrop-filter: blur(18px) saturate(1.4);
  border-radius: 24px;
  padding: 1.9rem 1.6rem 1.7rem;
  width: 100%;
  max-width: 380px;
  box-shadow: 0 24px 60px rgba(49, 10, 101, 0.38), inset 0 1px 0 rgba(255,255,255,0.35);
  border: 1px solid rgba(255,255,255,0.3);
  position: relative;
  z-index: 1;
}

#login-form, #register-form {
  display: block;
  width: 100%;
}

#login-form input, #register-form input, #register-form select {
  width: 100%;
  padding: 14px 18px;
  border: 2px solid rgba(255,255,255,0.4);
  border-radius: 14px;
  font-family: var(--font-sans);
  font-size: 1rem;
  margin-bottom: 12px;
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast), background var(--transition-fast);
  outline: none;
  background: rgba(255,255,255,0.88);
  color: var(--text);
}

#login-form input:focus, #register-form input:focus, #register-form select:focus {
  border-color: #A78BFA;
  background: #FFFFFF;
  box-shadow: 0 0 0 4px rgba(167,139,250,0.3), 0 6px 18px rgba(79,70,229,0.18);
}

#login-form input::placeholder, #register-form input::placeholder {
  color: var(--text-muted);
}

/* 卡片内按钮 */
.login-card .btn {
  border-radius: 14px;
  margin-top: 4px;
}
.login-card .btn-primary {
  background: linear-gradient(135deg, #4F46E5 0%, #7C3AED 100%);
  box-shadow: 0 8px 22px rgba(76, 29, 149, 0.45);
  letter-spacing: 0.1em;
}
.login-card .btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 12px 30px rgba(76, 29, 149, 0.55);
}
.login-card .btn-primary:active {
  transform: translateY(1px) scale(0.98);
  box-shadow: 0 4px 12px rgba(76, 29, 149, 0.4);
}
.login-card .btn-secondary {
  background: rgba(255,255,255,0.92);
  color: var(--primary);
  border: 1.5px solid rgba(79,70,229,0.28);
}
.login-card .btn-secondary:hover {
  background: #FFFFFF;
  border-color: var(--primary);
}

.grade-select label, .avatar-select label {
  display: block;
  font-weight: 600;
  margin-bottom: 8px;
  color: #FFFFFF;
  font-size: 0.95rem;
  text-shadow: 0 1px 6px rgba(0,0,0,0.15);
}

#register-form select {
  appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 12 12'%3E%3Cpath d='M3 4.5l3 3 3-3' stroke='%236B7280' stroke-width='1.5' fill='none' stroke-linecap='round' stroke-linejoin='round'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 14px center;
  padding-right: 40px;
  cursor: pointer;
}

.avatar-options {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  margin-bottom: 16px;
}

.avatar-opt {
  font-size: 1.8rem;
  font-family: var(--font-emoji);
  width: 48px;
  height: 48px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 50%;
  cursor: pointer;
  transition: all var(--transition-base);
  border: 3px solid transparent;
  background: rgba(255,255,255,0.14);
}

.avatar-opt:hover {
  transform: scale(1.15);
  background: rgba(255,255,255,0.3);
}

.avatar-opt.selected {
  border-color: #FFFFFF;
  background: rgba(255,255,255,0.32);
  box-shadow: 0 0 0 3px rgba(255,255,255,0.25), 0 4px 14px rgba(0,0,0,0.15);
}

.error-msg {
  color: #FECACA;
  margin-top: 0.9rem;
  font-size: 0.9rem;
  min-height: 1.5em;
  text-align: center;
  position: relative;
  z-index: 1;
  font-weight: 500;
  text-shadow: 0 1px 6px rgba(0,0,0,0.2);
}

/* 底部小装饰 */
.login-footer-decor {
  position: relative;
  z-index: 1;
  display: flex;
  justify-content: center;
  gap: 20px;
  margin-top: 1.8rem;
  font-size: 1.15rem;
  opacity: 0.9;
  filter: drop-shadow(0 3px 8px rgba(0,0,0,0.25));
}
.login-footer-decor span {
  display: inline-block;
  animation: footerBob 3s ease-in-out infinite;
}
.login-footer-decor span:nth-child(2) { animation-delay: -0.6s; }
.login-footer-decor span:nth-child(3) { animation-delay: -1.2s; }
.login-footer-decor span:nth-child(4) { animation-delay: -1.8s; }
.login-footer-decor span:nth-child(5) { animation-delay: -2.4s; }

@keyframes footerBob {
  0%, 100% { transform: translateY(0) rotate(-4deg); }
  50% { transform: translateY(-6px) rotate(4deg); }
}

/* === 按钮系统 === */
.btn {
  display: block;
  width: 100%;
  padding: 14px 20px;
  border: none;
  border-radius: var(--radius-md);
  font-family: var(--font-sans);
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: all var(--transition-slow);
  margin-top: 8px;
  position: relative;
  overflow: hidden;
  letter-spacing: 0.02em;
}

.btn:active { transform: scale(0.97); }

.btn::after {
  content: '';
  position: absolute;
  top: 50%;
  left: 50%;
  width: 0;
  height: 0;
  background: rgba(255,255,255,0.2);
  border-radius: 50%;
  transform: translate(-50%, -50%);
  transition: width 0.6s, height 0.6s;
}

.btn:active::after {
  width: 300px;
  height: 300px;
}

.btn-primary {
  background: var(--gradient-primary);
  color: white;
  box-shadow: 0 4px 15px rgba(79,70,229,0.3);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 25px rgba(79,70,229,0.4);
}

.btn-primary:active {
  transform: translateY(0);
}

.btn-secondary {
  background: var(--border-light);
  color: var(--text-secondary);
}

.btn-secondary:hover {
  background: var(--border);
  transform: translateY(-1px);
}

/* === 顶部毛玻璃头部卡 === */
.top-bar {
  position: sticky;
  top: 0;
  z-index: 100;
  padding: 14px 18px 18px;
  background: linear-gradient(140deg, rgba(79,70,229,0.94) 0%, rgba(109,40,217,0.94) 55%, rgba(124,58,237,0.94) 100%);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  color: white;
  box-shadow: 0 6px 26px rgba(79,70,229,0.3);
  border-bottom: 1px solid rgba(255,255,255,0.16);
  border-radius: 0 0 26px 26px;
  overflow: hidden;
  transition: transform 0.32s cubic-bezier(0.4,0,0.2,1), box-shadow 0.32s;
}
/* 向下滚动隐藏顶栏，向上滚动显示 */
.top-bar.top-bar-hide {
  transform: translateY(-100%);
  box-shadow: none;
}

/* 头部卡装饰光斑 */
.top-bar::before,
.top-bar::after {
  content: '';
  position: absolute;
  border-radius: 50%;
  pointer-events: none;
  background: radial-gradient(circle, rgba(255,255,255,0.14) 0%, transparent 70%);
}
.top-bar::before { width: 170px; height: 170px; top: -70px; right: -40px; }
.top-bar::after { width: 130px; height: 130px; bottom: -60px; left: -45px; }

.hero-head-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  position: relative;
  z-index: 1;
}

.user-info {
  display: flex;
  align-items: center;
  gap: 10px;
  min-width: 0;
  flex: 1;
}

.avatar {
  font-size: 1.8rem;
  font-family: var(--font-emoji);
  width: 44px;
  height: 44px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(255,255,255,0.22);
  border: 1.5px solid rgba(255,255,255,0.38);
  border-radius: 15px;
  backdrop-filter: blur(4px);
  filter: drop-shadow(0 3px 8px rgba(0,0,0,0.18));
  flex-shrink: 0;
}

.user-greet {
  line-height: 1.3;
  min-width: 0;
}

.greet-line {
  font-size: 0.98rem;
  font-weight: 700;
  letter-spacing: 0.01em;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.user-name {
  font-weight: 700;
  color: #FFF7ED;
}

.greet-sub {
  font-size: 0.68rem;
  opacity: 0.85;
  font-weight: 500;
  margin-top: 1px;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.top-actions {
  display: flex;
  gap: 5px;
  flex-shrink: 0;
}

.icon-btn {
  background: rgba(255,255,255,0.18);
  border: 1px solid rgba(255,255,255,0.24);
  border-radius: 11px;
  padding: 7px 9px;
  cursor: pointer;
  font-family: var(--font-sans);
  font-size: 0.8rem;
  font-weight: 600;
  color: white;
  transition: all var(--transition-base);
  backdrop-filter: blur(6px);
  white-space: nowrap;
}

.icon-btn:hover {
  background: rgba(255,255,255,0.32);
  transform: translateY(-1px);
}

.icon-btn:active { transform: scale(0.94); }

.icon-btn-book {
  font-size: 1.05rem;
  font-family: var(--font-emoji);
}

.grade-badge-text {
  font-size: 0.8rem;
  font-weight: 700;
  color: white;
  white-space: nowrap;
}

/* 今日学习进度 */
.hero-progress {
  position: relative;
  z-index: 1;
  margin-top: 14px;
  background: rgba(255,255,255,0.14);
  border: 1px solid rgba(255,255,255,0.2);
  border-radius: 16px;
  padding: 12px 14px;
  backdrop-filter: blur(8px);
}
.hero-progress-head {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 8px;
}
.hero-progress-label {
  font-size: 0.8rem;
  font-weight: 600;
  opacity: 0.95;
}
.hero-progress-text {
  font-size: 0.75rem;
  font-weight: 600;
  opacity: 0.9;
}
.progress-track {
  height: 10px;
  background: rgba(255,255,255,0.22);
  border-radius: 999px;
  overflow: hidden;
}
.progress-fill {
  height: 100%;
  width: 0%;
  border-radius: 999px;
  background: linear-gradient(90deg, #FDE68A, #FBBF24, #F59E0B);
  box-shadow: 0 0 12px rgba(251,191,36,0.55);
  transition: width 0.9s cubic-bezier(0.4, 0, 0.2, 1);
  position: relative;
  overflow: hidden;
}
.progress-fill::after {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(90deg, transparent, rgba(255,255,255,0.55), transparent);
  animation: shimmer 2s infinite;
}
@keyframes shimmer {
  0% { transform: translateX(-100%); }
  100% { transform: translateX(100%); }
}

/* 打卡 / 积分 / 年级 */
.hero-stats {
  position: relative;
  z-index: 1;
  display: flex;
  gap: 8px;
  margin-top: 10px;
}
.hero-stat {
  flex: 1;
  display: flex;
  align-items: center;
  gap: 8px;
  background: rgba(255,255,255,0.14);
  border: 1px solid rgba(255,255,255,0.2);
  border-radius: 14px;
  padding: 8px 10px;
  backdrop-filter: blur(8px);
  min-width: 0;
}
.hero-stat-icon {
  font-size: 1.15rem;
  flex-shrink: 0;
}
.hero-stat-body {
  display: flex;
  flex-direction: column;
  line-height: 1.2;
  min-width: 0;
}
.hero-stat-num {
  font-size: 1rem;
  font-weight: 800;
  white-space: nowrap;
}
.hero-stat-label {
  font-size: 0.62rem;
  opacity: 0.85;
  white-space: nowrap;
}
.hero-stat-grade {
  font-size: 0.82rem;
}

/* === 底部导航 === */
.bottom-nav {
  display: flex;
  background: rgba(255,255,255,0.92);
  backdrop-filter: blur(18px) saturate(1.3);
  -webkit-backdrop-filter: blur(18px) saturate(1.3);
  border-top: 1px solid rgba(79,70,229,0.1);
  position: fixed;
  bottom: 0;
  left: 0;
  right: 0;
  z-index: 100;
  padding: 6px 8px calc(6px + env(safe-area-inset-bottom));
  box-shadow: 0 -6px 24px rgba(79,70,229,0.1);
}

.nav-item {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 3px;
  padding: 7px 4px 6px;
  background: none;
  border: none;
  cursor: pointer;
  color: var(--text-light);
  font-size: 0.68rem;
  font-family: var(--font-sans);
  font-weight: 600;
  transition: color var(--transition-base), background var(--transition-base), box-shadow var(--transition-base);
  border-radius: 14px;
  position: relative;
  -webkit-tap-highlight-color: transparent;
}

.nav-item .nav-icon {
  font-size: 1.35rem;
  font-family: var(--font-emoji);
  transition: transform var(--transition-base);
  filter: grayscale(0.25);
}

.nav-item.active {
  color: var(--primary);
  background: linear-gradient(135deg, rgba(79,70,229,0.13), rgba(124,58,237,0.13));
  box-shadow: 0 0 18px rgba(79,70,229,0.22), inset 0 0 0 1.5px rgba(79,70,229,0.22);
}

.nav-item.active .nav-icon {
  transform: translateY(-1px) scale(1.12);
  filter: grayscale(0);
  animation: navIconBob 1.6s ease-in-out infinite;
}

@keyframes navIconBob {
  0%, 100% { transform: translateY(-1px) scale(1.12); }
  50% { transform: translateY(-3px) scale(1.17); }
}

.nav-item.active::after {
  content: '';
  position: absolute;
  top: -5px;
  left: 50%;
  transform: translateX(-50%);
  width: 26px;
  height: 3.5px;
  background: var(--gradient-primary);
  border-radius: 0 0 4px 4px;
  box-shadow: 0 2px 8px rgba(79,70,229,0.55);
}

/* === 内容区 === */
.content {
  padding: 18px 16px 110px;
  max-width: 768px;
  margin: 0 auto;
}

.tab-content { display: none; }
.tab-content.active { display: block; animation: fadeIn 0.3s ease-out; }

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(10px); }
  to { opacity: 1; transform: translateY(0); }
}

/* === 区块 === */
.section {
  margin-bottom: 30px;
}

.section h2 {
  font-size: 1.15rem;
  margin-bottom: 16px;
  color: var(--text);
  font-weight: 700;
  letter-spacing: -0.01em;
  display: flex;
  align-items: center;
  gap: 8px;
}

.section h2::before {
  content: '';
  width: 4px;
  height: 18px;
  border-radius: 4px;
  background: var(--gradient-primary);
  flex-shrink: 0;
}

/* === 科目网格（各科目差异化配色） === */
.subject-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
  gap: 14px;
}

.subject-card {
  background: var(--card-bg);
  border-radius: 20px;
  padding: 20px 14px 16px;
  text-align: center;
  cursor: pointer;
  transition: all var(--transition-slow);
  box-shadow: 0 4px 14px rgba(79,70,229,0.07);
  border: 1.5px solid var(--border-light);
  position: relative;
  overflow: hidden;
  display: flex;
  flex-direction: column;
}

/* 顶部渐变色条（每科目不同） */
.subject-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 5px;
  background: var(--subj-grad, var(--gradient-primary));
}

/* 右上角柔和光晕 */
.subject-card::after {
  content: '';
  position: absolute;
  top: -46px;
  right: -46px;
  width: 120px;
  height: 120px;
  border-radius: 50%;
  background: var(--subj-glow, rgba(79,70,229,0.1));
  pointer-events: none;
}

.subject-card:hover {
  transform: translateY(-5px);
  box-shadow: 0 14px 34px var(--subj-glow-strong, rgba(79,70,229,0.18));
  border-color: var(--subj-border, var(--primary-lighter));
}

.subject-card:active { transform: scale(0.96); }

/* 各科目主题色 */
[data-subject="数学"] {
  --subj-grad: linear-gradient(90deg, #6366F1, #8B5CF6);
  --subj-soft: rgba(99,102,241,0.13);
  --subj-glow: rgba(99,102,241,0.11);
  --subj-glow-strong: rgba(99,102,241,0.26);
}
[data-subject="物理"] {
  --subj-grad: linear-gradient(90deg, #06B6D4, #3B82F6);
  --subj-soft: rgba(6,182,212,0.13);
  --subj-glow: rgba(6,182,212,0.11);
  --subj-glow-strong: rgba(6,182,212,0.26);
}
[data-subject="生物"] {
  --subj-grad: linear-gradient(90deg, #10B981, #34D399);
  --subj-soft: rgba(16,185,129,0.13);
  --subj-glow: rgba(16,185,129,0.11);
  --subj-glow-strong: rgba(16,185,129,0.26);
}
[data-subject="地理"] {
  --subj-grad: linear-gradient(90deg, #F59E0B, #F97316);
  --subj-soft: rgba(245,158,11,0.15);
  --subj-glow: rgba(245,158,11,0.12);
  --subj-glow-strong: rgba(245,158,11,0.28);
}
[data-subject="历史"] {
  --subj-grad: linear-gradient(90deg, #B45309, #92400E);
  --subj-soft: rgba(180,83,9,0.13);
  --subj-glow: rgba(180,83,9,0.11);
  --subj-glow-strong: rgba(180,83,9,0.26);
}
[data-subject="道德与法治"] {
  --subj-grad: linear-gradient(90deg, #EF4444, #F43F5E);
  --subj-soft: rgba(239,68,68,0.13);
  --subj-glow: rgba(239,68,68,0.11);
  --subj-glow-strong: rgba(239,68,68,0.26);
}
[data-subject="语文"] {
  --subj-grad: linear-gradient(90deg, #EC4899, #F472B6);
  --subj-soft: rgba(236,72,153,0.13);
  --subj-glow: rgba(236,72,153,0.11);
  --subj-glow-strong: rgba(236,72,153,0.26);
}
[data-subject="英语"] {
  --subj-grad: linear-gradient(90deg, #0EA5E9, #6366F1);
  --subj-soft: rgba(14,165,233,0.13);
  --subj-glow: rgba(14,165,233,0.11);
  --subj-glow-strong: rgba(14,165,233,0.26);
}
[data-subject="化学"] {
  --subj-grad: linear-gradient(90deg, #14B8A6, #84CC16);
  --subj-soft: rgba(20,184,166,0.13);
  --subj-glow: rgba(20,184,166,0.11);
  --subj-glow-strong: rgba(20,184,166,0.26);
}

.subject-icon {
  font-size: 2rem;
  font-family: var(--font-emoji);
  width: 58px;
  height: 58px;
  margin: 2px auto 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 18px;
  background: var(--subj-soft, var(--primary-bg));
  box-shadow: 0 4px 14px var(--subj-glow, rgba(79,70,229,0.15)), inset 0 1px 0 rgba(255,255,255,0.8);
  transition: transform var(--transition-base);
}

.subject-card:hover .subject-icon {
  transform: scale(1.08) rotate(-4deg);
}

.subject-name {
  font-weight: 700;
  font-size: 1.02rem;
  color: var(--text);
  margin-bottom: 2px;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.subject-count {
  font-size: 0.78rem;
  color: var(--text-light);
  margin-top: 4px;
}

/* 版本作用域标签（如"小学通用"、"仅三年级"） */
.version-scope-badge {
  display: inline-block;
  font-size: 10px;
  padding: 2px 7px;
  border-radius: 8px;
  background: #E0E7FF;
  color: #4338CA;
  margin-top: 4px;
  white-space: nowrap;
}

/* === 章节列表 === */
.section-header {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 16px;
  flex-wrap: wrap;
}

.section-header h2 {
  margin-bottom: 0;
  font-size: 1.15rem;
}

.back-btn {
  background: none;
  border: none;
  color: var(--primary);
  font-family: var(--font-sans);
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  padding: 8px 4px;
  transition: opacity var(--transition-fast);
  display: flex;
  align-items: center;
  gap: 4px;
}

.back-btn:hover {
  opacity: 0.7;
}

.version-tag {
  display: inline-block;
  background: var(--primary-bg);
  color: var(--primary-dark);
  padding: 4px 12px;
  border-radius: var(--radius-full);
  font-size: 0.8rem;
  font-weight: 600;
  margin-bottom: 16px;
}

.chapter-list {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.chapter-item {
  background: var(--card-bg);
  border-radius: var(--radius-md);
  padding: 16px 20px;
  cursor: pointer;
  transition: all var(--transition-base);
  box-shadow: var(--shadow-sm);
  display: flex;
  align-items: center;
  gap: 14px;
  border: 2px solid transparent;
}

.chapter-item:hover {
  border-color: var(--primary-lighter);
  box-shadow: var(--shadow-md);
  transform: translateX(4px);
}

.chapter-item:active { transform: scale(0.99); }

.chapter-num {
  background: var(--gradient-primary);
  color: white;
  width: 34px;
  height: 34px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 0.85rem;
  flex-shrink: 0;
  box-shadow: 0 2px 8px rgba(79,70,229,0.25);
}

.chapter-text {
  flex: 1;
  font-size: 0.95rem;
  line-height: 1.5;
  color: var(--text);
}

.chapter-arrow {
  color: var(--text-light);
  font-size: 1.2rem;
  opacity: 0.5;
  transition: opacity var(--transition-fast), transform var(--transition-fast);
}

.chapter-item:hover .chapter-arrow {
  opacity: 1;
  transform: translateX(4px);
}

/* === 加载状态 === */
.loading-box {
  text-align: center;
  padding: 60px 20px;
}

.spinner {
  width: 44px;
  height: 44px;
  border: 4px solid var(--primary-lighter);
  border-top-color: var(--primary);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
  margin: 0 auto 20px;
}

@keyframes spin {
  to { transform: rotate(360deg); }
}

.loading-box p {
  font-size: 1.05rem;
  color: var(--text-secondary);
  margin-bottom: 8px;
}

.loading-box .hint {
  color: var(--text-light);
  font-size: 0.85rem;
  margin-top: 4px;
}

/* === 答题页面 === */
.quiz-progress {
  font-size: 0.9rem;
  color: var(--text-light);
  font-weight: 600;
  margin-left: auto;
}

.question-card {
  background: var(--card-bg);
  border-radius: var(--radius-xl);
  padding: 24px;
  margin-bottom: 16px;
  box-shadow: var(--shadow-md);
  border: 1px solid rgba(79,70,229,0.06);
}

.question-type {
  display: inline-block;
  padding: 4px 12px;
  border-radius: 6px;
  font-size: 0.75rem;
  font-weight: 600;
  margin-bottom: 14px;
  letter-spacing: 0.03em;
}

.question-type.choice { background: var(--info-bg); color: var(--info-text); }
.question-type.judge { background: var(--warning-bg); color: var(--warning-text); }
.question-type.short { background: var(--success-bg); color: var(--success-text); }

.question-text {
  font-size: 1.1rem;
  line-height: 1.7;
  color: var(--text);
  font-weight: 500;
}

.options-area {
  display: flex;
  flex-direction: column;
  gap: 10px;
  margin-bottom: 16px;
}

.option-btn {
  background: var(--card-bg);
  border: 2px solid var(--border);
  border-radius: var(--radius-md);
  padding: 16px 20px;
  text-align: left;
  font-family: var(--font-sans);
  font-size: 1rem;
  cursor: pointer;
  transition: all var(--transition-base);
  color: var(--text);
  line-height: 1.5;
}

.option-btn:hover {
  border-color: var(--primary-light);
  background: var(--primary-bg);
  transform: translateX(2px);
}

.option-btn.selected {
  border-color: var(--primary);
  background: rgba(79,70,229,0.08);
  box-shadow: 0 0 0 3px rgba(79,70,229,0.1);
}

.option-btn.correct {
  border-color: var(--success);
  background: var(--success-bg);
  color: var(--success-text);
}

.option-btn.wrong {
  border-color: var(--danger);
  background: var(--danger-bg);
  color: var(--danger-text);
}

.option-btn input[type="radio"] {
  display: none;
}

/* 反馈区域 */
.feedback {
  padding: 16px 20px;
  border-radius: var(--radius-md);
  margin-bottom: 12px;
  font-weight: 600;
  font-size: 1.05rem;
  animation: slideDown 0.3s ease-out;
}

@keyframes slideDown {
  from { opacity: 0; transform: translateY(-10px); }
  to { opacity: 1; transform: translateY(0); }
}

.feedback.correct { background: var(--success-bg); color: var(--success-text); }
.feedback.wrong { background: var(--danger-bg); color: var(--danger-text); }

.explanation {
  background: var(--primary-bg);
  border-radius: var(--radius-md);
  padding: 16px 20px;
  margin-bottom: 16px;
  color: var(--text);
  line-height: 1.7;
  font-size: 0.95rem;
  border-left: 4px solid var(--primary);
  animation: slideDown 0.3s ease-out;
}

.explanation::before {
  content: "💡 解析：";
  font-weight: 600;
  font-family: var(--font-sans), var(--font-emoji);
}

/* 判断题选项 */
.judge-options {
  display: flex;
  gap: 16px;
  margin-bottom: 16px;
}

.judge-btn {
  flex: 1;
  background: var(--card-bg);
  border: 2px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 24px;
  text-align: center;
  font-family: var(--font-sans);
  font-size: 1.3rem;
  font-weight: 700;
  cursor: pointer;
  transition: all var(--transition-base);
  color: var(--text);
}

.judge-btn:hover { border-color: var(--primary-light); background: var(--primary-bg); }
.judge-btn.selected { border-color: var(--primary); background: rgba(79,70,229,0.08); }
.judge-btn.correct { border-color: var(--success); background: var(--success-bg); color: var(--success-text); }
.judge-btn.wrong { border-color: var(--danger); background: var(--danger-bg); color: var(--danger-text); }

/* 简答题输入 */
.short-answer-input {
  width: 100%;
  min-height: 120px;
  padding: 16px;
  border: 2px solid var(--border);
  border-radius: var(--radius-md);
  font-family: var(--font-sans);
  font-size: 1rem;
  line-height: 1.7;
  resize: vertical;
  outline: none;
  margin-bottom: 16px;
  color: var(--text);
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
}

.short-answer-input:focus {
  border-color: var(--primary);
  box-shadow: 0 0 0 4px rgba(79,70,229,0.08);
}

.quiz-actions {
  display: flex;
  gap: 12px;
  flex-direction: column;
}

/* === 结果页 === */
.result-container {
  text-align: center;
  padding: 40px 20px;
  background: var(--card-bg);
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow-lg);
  margin-top: 20px;
}

.result-emoji {
  font-size: 4rem;
  font-family: var(--font-emoji);
  margin-bottom: 16px;
  animation: resultBounce 0.6s ease-out;
}

@keyframes resultBounce {
  0% { transform: scale(0); }
  50% { transform: scale(1.2); }
  100% { transform: scale(1); }
}

.result-container h2 {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 8px;
}

.result-score {
  margin: 20px 0;
}

.score-num {
  font-size: 4rem;
  font-weight: 800;
  background: var(--gradient-primary);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  letter-spacing: -0.03em;
}

.result-score span:not(.score-num) {
  font-size: 1.3rem;
  color: var(--text-light);
  font-weight: 500;
}

.result-details {
  color: var(--text-light);
  font-size: 1rem;
  margin-bottom: 28px;
  line-height: 1.8;
}

.result-details span {
  font-weight: 600;
  color: var(--text);
}

.result-actions {
  display: flex;
  flex-direction: column;
  gap: 10px;
  max-width: 300px;
  margin: 0 auto;
}

/* === 错题本 === */
.wrong-subject-tabs {
  display: flex;
  gap: 8px;
  margin-bottom: 16px;
  overflow-x: auto;
  padding-bottom: 8px;
  -webkit-overflow-scrolling: touch;
}

.wrong-subject-tab {
  padding: 8px 18px;
  border-radius: var(--radius-full);
  border: 2px solid var(--border);
  background: var(--card-bg);
  font-family: var(--font-sans);
  font-size: 0.9rem;
  font-weight: 600;
  cursor: pointer;
  white-space: nowrap;
  transition: all var(--transition-base);
  color: var(--text-secondary);
}

.wrong-subject-tab.active {
  border-color: var(--primary);
  background: var(--primary-bg);
  color: var(--primary-dark);
}

.wrong-list {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.wrong-item {
  background: var(--card-bg);
  border-radius: var(--radius-lg);
  padding: 18px 20px;
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--border-light);
  transition: box-shadow var(--transition-base);
}

.wrong-item:hover {
  box-shadow: var(--shadow-md);
}

.wrong-item-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 8px;
}

.wrong-item-chapter {
  font-size: 0.8rem;
  color: var(--text-light);
}

.wrong-item-question {
  font-size: 0.95rem;
  line-height: 1.6;
  margin-bottom: 12px;
  color: var(--text);
}

.wrong-item-answers {
  display: flex;
  flex-direction: column;
  gap: 6px;
  font-size: 0.85rem;
}

.wrong-item-answers .user-ans {
  color: var(--danger);
}

.wrong-item-answers .correct-ans {
  color: var(--success);
}

.wrong-item-explanation {
  margin-top: 12px;
  padding: 12px;
  background: var(--primary-bg);
  border-radius: var(--radius-sm);
  font-size: 0.85rem;
  color: var(--text-secondary);
  line-height: 1.6;
  border-left: 3px solid var(--primary);
}

.master-btn {
  padding: 6px 16px;
  border-radius: var(--radius-sm);
  border: 2px solid var(--success);
  background: var(--card-bg);
  color: var(--success);
  font-family: var(--font-sans);
  font-size: 0.8rem;
  font-weight: 600;
  cursor: pointer;
  transition: all var(--transition-fast);
}

.master-btn:hover {
  background: var(--success-bg);
}

.empty-state {
  text-align: center;
  padding: 60px 20px;
  color: var(--text-light);
  font-size: 1.1rem;
}

/* === 排行榜 === */
.leaderboard-list {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.leaderboard-item {
  background: var(--card-bg);
  border-radius: var(--radius-md);
  padding: 16px 20px;
  display: flex;
  align-items: center;
  gap: 16px;
  box-shadow: var(--shadow-sm);
  transition: box-shadow var(--transition-base);
  border: 2px solid transparent;
}

.leaderboard-item:hover {
  box-shadow: var(--shadow-md);
}

.leaderboard-item.me {
  border-color: var(--primary-lighter);
  background: var(--primary-bg);
}

.rank-num {
  font-size: 1.3rem;
  font-weight: 800;
  width: 36px;
  text-align: center;
  font-variant-numeric: tabular-nums;
}

.rank-num.gold { color: var(--warning); }
.rank-num.silver { color: var(--text-muted); }
.rank-num.bronze { color: #D97706; }

.rank-avatar {
  font-size: 1.8rem;
  font-family: var(--font-emoji);
}

.rank-info {
  flex: 1;
}

.rank-name {
  font-weight: 600;
  font-size: 1rem;
  color: var(--text);
}

.rank-streak {
  font-size: 0.8rem;
  color: var(--text-light);
  margin-top: 2px;
}

.rank-score {
  font-weight: 700;
  font-size: 1.2rem;
  color: var(--primary);
}

/* === 统计卡片 === */
.stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(150px, 1fr));
  gap: 12px;
}

.stat-card {
  background: var(--card-bg);
  border-radius: var(--radius-md);
  padding: 18px 16px;
  text-align: center;
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--border-light);
  transition: transform var(--transition-base), box-shadow var(--transition-base);
}

.stat-card:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

.stat-value {
  font-size: 1.8rem;
  font-weight: 800;
  color: var(--primary);
  line-height: 1.2;
}

.stat-label {
  font-size: 0.8rem;
  color: var(--text-light);
  margin-top: 6px;
  font-weight: 500;
}

/* === 个人页面 === */
.profile-card {
  background: var(--gradient-primary);
  border-radius: var(--radius-xl);
  padding: 36px 20px 28px;
  text-align: center;
  color: white;
  margin-bottom: 24px;
  box-shadow: 0 8px 30px rgba(79,70,229,0.3);
  position: relative;
  overflow: hidden;
}

.profile-card::before {
  content: '';
  position: absolute;
  top: -50%;
  right: -50%;
  width: 100%;
  height: 100%;
  background: radial-gradient(circle, rgba(255,255,255,0.1) 0%, transparent 70%);
  pointer-events: none;
}

.profile-avatar {
  font-size: 3.5rem;
  font-family: var(--font-emoji);
  margin-bottom: 12px;
  filter: drop-shadow(0 4px 8px rgba(0,0,0,0.15));
}

.profile-card h2 {
  font-size: 1.4rem;
  font-weight: 700;
  margin-bottom: 4px;
  color: white;
}

.profile-card p {
  opacity: 0.85;
  font-size: 0.95rem;
  font-weight: 500;
}

.profile-actions {
  margin-top: 24px;
  max-width: 300px;
}

/* === 单元头部 === */
.unit-header {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 14px 18px;
  margin-top: 16px;
  background: var(--gradient-primary);
  color: white;
  border-radius: var(--radius-md);
  font-weight: 600;
  font-size: 0.95rem;
  box-shadow: 0 4px 12px rgba(79,70,229,0.2);
}

.unit-num {
  width: 28px;
  height: 28px;
  background: rgba(255,255,255,0.2);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.8rem;
  flex-shrink: 0;
  backdrop-filter: blur(4px);
}

.unit-lesson-count {
  margin-left: auto;
  font-size: 0.75rem;
  opacity: 0.8;
  font-weight: normal;
}

/* === 预习页面 === */
.study-content {
  padding: 20px;
  background: var(--card-bg);
  border-radius: var(--radius-lg);
  margin: 12px 0;
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--border-light);
}

.study-body {
  font-size: 0.95rem;
  line-height: 1.9;
  color: var(--text);
}

.study-body h3 {
  font-size: 1.1rem;
  margin: 20px 0 10px;
  color: var(--primary);
  border-bottom: 2px solid var(--primary-bg);
  padding-bottom: 6px;
  letter-spacing: 0.01em;
}

.study-section-title {
  font-size: 1rem;
  font-weight: 700;
  color: var(--primary);
  margin: 16px 0 8px;
  padding: 6px 12px;
  background: var(--primary-bg);
  border-radius: 6px;
  display: inline-block;
}

.study-body li {
  margin: 4px 0 4px 20px;
  list-style: disc;
}

.source-tag {
  display: inline-block;
  padding: 3px 12px;
  border-radius: var(--radius-full);
  font-size: 0.7rem;
  font-weight: 600;
  margin-bottom: 8px;
}

.source-tag.cached { background: var(--success-bg); color: var(--success-text); }
.source-tag.ai { background: var(--info-bg); color: var(--info-text); }

.study-actions {
  display: flex;
  flex-direction: column;
  gap: 10px;
  padding: 16px 0;
}

.btn-large {
  font-size: 1.05rem;
  padding: 16px 24px;
}

/* === 课文原文 === */
.original-text-block {
  background: linear-gradient(135deg, #FFFBEB 0%, #FEF3C7 100%);
  border-radius: var(--radius-md);
  padding: 20px;
  margin: 0 0 16px 0;
  border-left: 4px solid var(--warning);
  box-shadow: 0 2px 8px rgba(245, 158, 11, 0.08);
}

.original-text-block .ot-title {
  font-size: 1rem;
  font-weight: 600;
  color: var(--warning-text);
  margin-bottom: 14px;
  display: flex;
  align-items: center;
  gap: 6px;
}

.original-text-block .ot-content {
  font-size: 1rem;
  line-height: 2;
  color: #78350F;
  white-space: pre-wrap;
  font-family: var(--font-kai);
  text-align: justify;
}

.original-title {
  font-size: 1.3em;
  font-weight: bold;
  text-align: center;
  margin-bottom: 8px;
  color: var(--text);
}

.original-author {
  font-size: 0.95em;
  text-align: center;
  color: var(--text-light);
  margin-bottom: 20px;
}

/* === 模态弹窗 === */
.modal-overlay {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: rgba(0,0,0,0.5);
  z-index: 1000;
  display: flex;
  align-items: center;
  justify-content: center;
  animation: fadeIn 0.2s ease-out;
  backdrop-filter: blur(4px);
}

.modal-content {
  background: var(--card-bg);
  border-radius: var(--radius-xl);
  width: 90%;
  max-width: 400px;
  max-height: 80vh;
  overflow-y: auto;
  box-shadow: var(--shadow-xl);
  animation: modalSlideIn 0.25s ease-out;
}

@keyframes modalSlideIn {
  from { opacity: 0; transform: scale(0.95) translateY(10px); }
  to { opacity: 1; transform: scale(1) translateY(0); }
}

.modal-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 18px 20px;
  border-bottom: 1px solid var(--border-light);
}

.modal-header h3 {
  margin: 0;
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--text);
}

.modal-close {
  background: none;
  border: none;
  font-size: 1.3rem;
  color: var(--text-muted);
  cursor: pointer;
  padding: 4px 8px;
  border-radius: 6px;
  transition: background var(--transition-fast), color var(--transition-fast);
  line-height: 1;
}

.modal-close:hover {
  background: var(--border-light);
  color: var(--text);
}

.modal-body {
  padding: 20px;
}

/* 年级选择弹窗 */
.grade-group {
  margin-bottom: 24px;
}

.grade-group:last-child {
  margin-bottom: 0;
}

.grade-group h4 {
  margin: 0 0 12px;
  font-size: 0.9rem;
  color: var(--text-light);
  font-weight: 600;
  letter-spacing: 0.02em;
}

.grade-options {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.grade-option-btn {
  padding: 10px 20px;
  border-radius: 10px;
  border: 2px solid var(--border);
  background: var(--card-bg);
  font-family: var(--font-sans);
  font-size: 0.9rem;
  cursor: pointer;
  transition: all var(--transition-base);
  color: var(--text-secondary);
  font-weight: 500;
}

.grade-option-btn:hover {
  border-color: var(--primary-lighter);
  background: var(--primary-bg);
}

.grade-option-btn:active { transform: scale(0.95); }

.grade-option-btn.current {
  border-color: var(--primary);
  background: var(--primary-bg);
  color: var(--primary);
  font-weight: 600;
}

.grade-badge-text {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--primary);
  white-space: nowrap;
}

/* === 记忆训练 === */
.memory-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 14px;
  padding: 8px 0;
}

.memory-card {
  border-radius: var(--radius-lg);
  padding: 24px 16px 20px;
  color: white;
  cursor: pointer;
  text-align: center;
  transition: all var(--transition-slow);
  box-shadow: 0 6px 20px rgba(0,0,0,0.12);
  position: relative;
  overflow: hidden;
}

.memory-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: linear-gradient(180deg, rgba(255,255,255,0.1) 0%, transparent 50%);
  pointer-events: none;
}

.memory-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 10px 30px rgba(0,0,0,0.18);
}

.memory-card:active { transform: scale(0.97); }

.memory-card-icon {
  font-size: 2.2rem;
  font-family: var(--font-emoji);
  margin-bottom: 10px;
  filter: drop-shadow(0 2px 4px rgba(0,0,0,0.1));
}

.memory-card-title {
  font-size: 1.1rem;
  font-weight: 700;
  margin-bottom: 4px;
  letter-spacing: 0.02em;
}

.memory-card-desc {
  font-size: 0.75rem;
  opacity: 0.85;
}

/* 记忆训练详情 */
.memory-step-container {
  padding: 20px;
  min-height: 80vh;
}

.memory-back-btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 12px 20px;
  font-family: var(--font-sans);
  font-size: 1rem;
  color: var(--text-secondary);
  background: var(--border-light);
  border: none;
  border-radius: var(--radius-md);
  cursor: pointer;
  margin-bottom: 20px;
  transition: background var(--transition-fast);
}

.memory-back-btn:hover {
  background: var(--border);
}

.memory-step-title {
  font-size: 1.6rem;
  font-weight: 700;
  color: var(--text);
  text-align: center;
  margin-bottom: 8px;
  letter-spacing: -0.01em;
}

.memory-step-subtitle {
  font-size: 1.05rem;
  color: var(--text-light);
  text-align: center;
  margin-bottom: 30px;
}

.memory-option-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 20px;
  max-width: 500px;
  margin: 0 auto;
}

.memory-big-btn {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 30px 20px;
  min-height: 140px;
  background: var(--gradient-primary);
  color: white;
  border: none;
  border-radius: var(--radius-xl);
  cursor: pointer;
  transition: all var(--transition-slow);
  box-shadow: 0 4px 15px rgba(79,70,229,0.3);
}

.memory-big-btn:hover {
  transform: translateY(-3px);
  box-shadow: 0 8px 25px rgba(79,70,229,0.4);
}

.memory-big-btn:active { transform: scale(0.97); }

.memory-big-btn.wrong-btn {
  background: var(--gradient-card-2);
  box-shadow: 0 4px 15px rgba(245,87,108,0.3);
}

.memory-big-btn .btn-icon {
  font-size: 2.5rem;
  margin-bottom: 10px;
}

.memory-big-btn .btn-text {
  font-size: 1.2rem;
  font-weight: 600;
  margin-bottom: 4px;
}

.memory-big-btn .btn-desc {
  font-size: 0.85rem;
  opacity: 0.9;
}

.memory-unit-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 15px;
  max-width: 400px;
  margin: 0 auto;
}

.memory-unit-btn {
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: 25px 15px;
  background: var(--card-bg);
  border: 2px solid var(--border);
  border-radius: var(--radius-lg);
  cursor: pointer;
  transition: all var(--transition-base);
}

.memory-unit-btn:hover {
  border-color: var(--primary-light);
  background: var(--primary-bg);
}

.memory-unit-btn .unit-name {
  font-size: 1.15rem;
  font-weight: 600;
  color: var(--text);
}

.memory-unit-btn .unit-count {
  font-size: 0.85rem;
  color: var(--text-light);
  margin-top: 5px;
}

.memory-mode-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 15px;
  max-width: 450px;
  margin: 0 auto;
}

.memory-mode-btn {
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: 28px 15px;
  background: var(--card-bg);
  border: 2px solid var(--border);
  border-radius: var(--radius-lg);
  cursor: pointer;
  transition: all var(--transition-base);
}

.memory-mode-btn:hover {
  border-color: var(--primary-light);
  background: var(--primary-bg);
  transform: translateY(-2px);
}

.memory-mode-btn .mode-icon {
  font-size: 2rem;
  font-family: var(--font-emoji);
  margin-bottom: 10px;
}

.memory-mode-btn .mode-name {
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--text);
  margin-bottom: 4px;
}

.memory-mode-btn .mode-desc {
  font-size: 0.8rem;
  color: var(--text-light);
}

/* 练习界面 */
.memory-practice-container {
  padding: 15px;
  min-height: 80vh;
}

.practice-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 16px 20px;
  background: var(--bg-alt);
  border-radius: var(--radius-md);
  margin-bottom: 20px;
}

.practice-progress {
  font-size: 1rem;
  font-weight: 600;
  color: var(--text-secondary);
}

.practice-score {
  font-size: 1rem;
  color: var(--success);
  font-weight: 600;
}

.practice-main {
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: 20px;
}

/* 翻卡模式 */
.flashcard-mode {
  padding: 10px;
}

.flashcard-hint {
  text-align: center;
  font-size: 1rem;
  color: var(--text-light);
  margin-bottom: 15px;
  animation: pulse 2s infinite;
}

@keyframes pulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.5; }
}

.flashcard-wrapper {
  width: 280px;
  height: 350px;
  perspective: 1000px;
  margin: 0 auto 20px;
  cursor: pointer;
}

.flashcard-inner {
  position: relative;
  width: 100%;
  height: 100%;
  transition: transform 0.6s cubic-bezier(0.4, 0, 0.2, 1);
  transform-style: preserve-3d;
}

.flashcard-inner.flipped {
  transform: rotateY(180deg);
}

.flashcard-front,
.flashcard-back {
  position: absolute;
  width: 100%;
  height: 100%;
  backface-visibility: hidden;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-xl);
  padding: 30px;
  box-shadow: var(--shadow-lg);
}

.flashcard-front {
  background: var(--gradient-primary);
  color: white;
}

.flashcard-back {
  background: var(--card-bg);
  border: 3px solid var(--primary);
  transform: rotateY(180deg);
}

.fc-word {
  font-size: 2.2rem;
  font-weight: 700;
  margin-bottom: 12px;
  letter-spacing: 0.02em;
}

.fc-phonetic {
  font-size: 1.1rem;
  opacity: 0.9;
  margin-bottom: 20px;
}

.flashcard-actions {
  display: flex;
  gap: 20px;
  margin-top: 20px;
}

.fc-btn {
  padding: 18px 36px;
  font-family: var(--font-sans);
  font-size: 1.1rem;
  border: none;
  border-radius: var(--radius-md);
  cursor: pointer;
  font-weight: 600;
  transition: all var(--transition-base);
}

.fc-btn:active { transform: scale(0.95); }

.fc-btn-red {
  background: var(--danger-bg);
  color: var(--danger);
}

.fc-btn-red:hover {
  background: #FECACA;
}

.fc-btn-green {
  background: var(--success-bg);
  color: var(--success-text);
}

.fc-btn-green:hover {
  background: #A7F3D0;
}

/* 虚拟键盘 */
.virtual-keyboard {
  width: 100%;
  max-width: 500px;
  margin: 12px auto;
  padding: 8px;
  background: var(--border-light);
  border-radius: var(--radius-md);
  user-select: none;
}

.vk-row {
  display: flex;
  justify-content: center;
  gap: 4px;
  margin-bottom: 4px;
}

.vk-row:last-child { margin-bottom: 0; }

.vk-key {
  min-width: 34px;
  height: 48px;
  border: none;
  border-radius: 10px;
  background: var(--card-bg);
  color: var(--text);
  font-family: var(--font-sans);
  font-size: 1.1rem;
  font-weight: 700;
  box-shadow: 0 2px 4px rgba(0,0,0,0.08);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all 0.1s;
  padding: 0 5px;
  -webkit-tap-highlight-color: transparent;
}

.vk-key:active {
  background: var(--primary);
  color: white;
  transform: scale(0.92);
}

.vk-key.vk-special {
  background: var(--border);
  color: var(--danger);
  font-size: 1.15rem;
  min-width: 40px;
}

.vk-key.vk-special:active {
  background: var(--danger);
  color: white;
}

/* === AI问答面板 === */
#ask-btn {
  position: fixed;
  bottom: 90px;
  right: 24px;
  width: 56px;
  height: 56px;
  border-radius: 50%;
  background: var(--gradient-primary);
  border: none;
  font-size: 26px;
  font-family: var(--font-emoji);
  cursor: pointer;
  box-shadow: 0 6px 20px rgba(79,70,229,0.4);
  z-index: 999;
  transition: all var(--transition-slow);
  display: flex;
  align-items: center;
  justify-content: center;
  color: transparent;
  text-shadow: 0 0 0 white;
}

#ask-btn:hover {
  transform: scale(1.1) rotate(5deg);
  box-shadow: 0 8px 30px rgba(79,70,229,0.5);
}

#ask-btn.active {
  background: var(--gradient-card-2);
  box-shadow: 0 6px 20px rgba(245,87,108,0.4);
}

.ask-panel {
  position: fixed;
  bottom: 90px;
  right: 24px;
  width: 380px;
  max-width: calc(100vw - 48px);
  height: 500px;
  max-height: calc(100vh - 140px);
  background: var(--card-bg);
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow-xl);
  border: 1px solid rgba(79,70,229,0.1);
  z-index: 998;
  display: flex;
  flex-direction: column;
  overflow: hidden;
  animation: slideUp 0.3s ease-out;
}

@keyframes slideUp {
  from { opacity: 0; transform: translateY(20px); }
  to { opacity: 1; transform: translateY(0); }
}

.ask-header {
  background: var(--gradient-primary);
  color: white;
  padding: 14px 18px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-weight: 600;
  font-size: 0.95rem;
}

.ask-close {
  background: rgba(255,255,255,0.2);
  border: none;
  color: white;
  width: 28px;
  height: 28px;
  border-radius: 50%;
  cursor: pointer;
  font-size: 0.9rem;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background var(--transition-fast);
}

.ask-close:hover {
  background: rgba(255,255,255,0.35);
}

.ask-messages {
  flex: 1;
  overflow-y: auto;
  padding: 16px;
  background: var(--bg-alt);
}

.ask-msg {
  margin-bottom: 12px;
  display: flex;
}

.ask-msg.user {
  justify-content: flex-end;
}

.ask-msg.ai {
  justify-content: flex-start;
}

.ask-bubble {
  max-width: 85%;
  padding: 10px 16px;
  border-radius: 16px;
  font-size: 0.9rem;
  line-height: 1.6;
  word-break: break-word;
}

.ask-msg.user .ask-bubble {
  background: var(--gradient-primary);
  color: white;
  border-bottom-right-radius: 4px;
}

.ask-msg.ai .ask-bubble {
  background: var(--card-bg);
  color: var(--text);
  border: 1px solid var(--border-light);
  border-bottom-left-radius: 4px;
}

.ask-bubble.loading {
  color: var(--text-light);
  font-style: italic;
}

.ask-input-area {
  display: flex;
  padding: 12px;
  border-top: 1px solid var(--border-light);
  background: var(--card-bg);
  gap: 8px;
  align-items: flex-end;
}

.ask-input-area textarea {
  flex: 1;
  border: 2px solid var(--border);
  border-radius: var(--radius-md);
  padding: 8px 12px;
  font-family: var(--font-sans);
  font-size: 0.9rem;
  resize: none;
  outline: none;
  max-height: 80px;
  transition: border-color var(--transition-fast);
  line-height: 1.5;
}

.ask-input-area textarea:focus {
  border-color: var(--primary);
}

#ask-send {
  background: var(--gradient-primary);
  color: white;
  border: none;
  border-radius: var(--radius-md);
  padding: 10px 18px;
  cursor: pointer;
  font-family: var(--font-sans);
  font-size: 0.9rem;
  font-weight: 600;
  white-space: nowrap;
  transition: opacity var(--transition-fast);
}

#ask-send:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

#ask-send:hover:not(:disabled) {
  opacity: 0.9;
}

/* === 系统状态提示 === */
.system-status {
  position: fixed;
  top: 70px;
  right: 16px;
  z-index: 200;
}

.status-dot {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 4px 12px;
  border-radius: var(--radius-full);
  font-size: 0.75rem;
  font-weight: 600;
}

.status-dot.online { background: var(--success-bg); color: var(--success-text); }
.status-dot.offline { background: var(--danger-bg); color: var(--danger-text); }

/* === 讲解视频 === */
.study-video-area {
  text-align: center;
  margin: 16px auto;
  padding: 0 16px;
}

.btn-video {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 12px 24px;
  border: 2px dashed var(--primary-lighter);
  border-radius: var(--radius-md);
  background: var(--primary-bg);
  color: var(--primary);
  font-family: var(--font-sans);
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: all var(--transition-base);
}

.btn-video:hover {
  background: var(--primary-lighter);
  border-color: var(--primary-light);
  transform: translateY(-2px);
}

.btn-video.has-video {
  border-style: solid;
  background: var(--success-bg);
  border-color: var(--success);
  color: var(--success-text);
}

.btn-video.has-video:hover {
  background: #BBF7D0;
}

.video-modal-content {
  max-width: 800px !important;
  width: 90% !important;
  padding: 0 !important;
  overflow: hidden;
}

.video-modal-body {
  padding: 16px;
  max-height: 70vh;
  overflow-y: auto;
}

.video-modal-body iframe {
  width: 100%;
  aspect-ratio: 16/9;
  border-radius: var(--radius-sm);
}

/* === 智能出题 === */
.sq-wrapper { padding: 16px; max-width: 500px; margin: 0 auto; }
.sq-header-area { text-align: center; margin-bottom: 24px; }
.sq-header-area h3 { font-size: 1.3rem; margin-bottom: 6px; color: var(--text); font-weight: 700; }
.sq-desc { color: var(--text-light); font-size: 0.9rem; }

.sq-step-card {
  background: var(--card-bg);
  border-radius: var(--radius-lg);
  padding: 18px;
  margin-bottom: 16px;
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--border-light);
}

.sq-step-label {
  font-size: 0.95rem;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 14px;
  display: flex;
  align-items: center;
  gap: 8px;
}

.sq-step-num {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 26px;
  height: 26px;
  border-radius: 50%;
  background: var(--gradient-primary);
  color: white;
  font-size: 0.85rem;
  font-weight: 700;
}

.sq-subject-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 10px;
}

.sq-card {
  background: var(--bg-alt);
  border: 2px solid var(--border);
  border-radius: var(--radius-md);
  padding: 14px 8px;
  text-align: center;
  cursor: pointer;
  transition: all var(--transition-base);
  position: relative;
  overflow: hidden;
}

.sq-card::before {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 4px;
  background: var(--card-color, var(--primary));
  opacity: 0.3;
  border-radius: 12px 12px 0 0;
}

.sq-card:hover {
  border-color: var(--primary-lighter);
  background: var(--primary-bg);
}

.sq-card:active { transform: scale(0.96); }

.sq-card.active {
  border-color: var(--card-color, var(--primary));
  background: color-mix(in srgb, var(--card-color, var(--primary)) 8%, white);
  box-shadow: 0 0 0 3px color-mix(in srgb, var(--card-color, var(--primary)) 15%, transparent);
}

.sq-card.active::before { opacity: 1; height: 5px; }

.sq-card-icon {
  font-size: 1.8rem;
  font-family: var(--font-emoji);
  margin-bottom: 6px;
}

.sq-card-name {
  font-size: 0.9rem;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 2px;
}

.sq-card-hint {
  font-size: 0.65rem;
  color: var(--text-muted);
  line-height: 1.3;
}

/* 智能出题 - 选项 */
.sq-range-row { display: flex; gap: 10px; }

.sq-range-btn {
  flex: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  padding: 12px;
  border: 2px solid var(--border);
  border-radius: var(--radius-md);
  background: var(--bg-alt);
  cursor: pointer;
  font-family: var(--font-sans);
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text-secondary);
  transition: all var(--transition-base);
}

.sq-range-btn:hover {
  border-color: var(--primary-lighter);
}

.sq-range-btn.active {
  border-color: var(--primary);
  background: var(--primary-bg);
  color: var(--primary-dark);
}

.sq-range-icon {
  font-size: 1.2rem;
  font-family: var(--font-emoji);
}

.sq-count-row { display: flex; gap: 8px; }

.sq-count-btn {
  flex: 1;
  padding: 10px;
  border: 2px solid var(--border);
  border-radius: 10px;
  background: var(--bg-alt);
  cursor: pointer;
  font-family: var(--font-sans);
  font-size: 0.95rem;
  font-weight: 700;
  color: var(--text-secondary);
  transition: all var(--transition-base);
}

.sq-count-btn.active {
  border-color: var(--success);
  background: var(--success-bg);
  color: var(--success-text);
}

.sq-tip {
  font-size: 0.8rem;
  color: var(--text-light);
  margin-top: 10px;
  text-align: center;
}

.sq-start-btn {
  display: block;
  width: 100%;
  padding: 16px;
  border: none;
  border-radius: var(--radius-md);
  background: var(--gradient-primary);
  color: white;
  font-family: var(--font-sans);
  font-size: 1.05rem;
  font-weight: 700;
  cursor: pointer;
  margin-top: 8px;
  transition: all var(--transition-slow);
  box-shadow: 0 4px 14px rgba(79,70,229,0.3);
}

.sq-start-btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 20px rgba(79,70,229,0.4);
}

.sq-start-btn:active { transform: scale(0.97); }

/* 错题本分组 */
.wrong-subject-group { margin-bottom: 12px; }

.wrong-subject-title {
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--text);
  padding: 12px 0 8px;
  border-bottom: 2px solid var(--border);
  margin-bottom: 10px;
  display: flex;
  align-items: center;
  gap: 8px;
}

.wrong-count {
  font-size: 0.8rem;
  color: var(--text-muted);
  font-weight: 400;
}

.wrong-chapter-group {
  margin-bottom: 8px;
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  overflow: hidden;
}

.wrong-chapter-title {
  padding: 10px 14px;
  font-family: var(--font-sans);
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-secondary);
  background: var(--bg-alt);
  cursor: pointer;
  list-style: none;
  display: flex;
  align-items: center;
  gap: 6px;
  transition: background var(--transition-fast);
}

.wrong-chapter-title::before {
  content: '▶';
  font-size: 0.65rem;
  transition: transform 0.2s;
  color: var(--text-light);
}

details[open] > .wrong-chapter-title::before { transform: rotate(90deg); }

.wrong-chapter-title:hover { background: var(--border-light); }

/* === 响应式 === */
@media (min-width: 768px) {
  .subject-grid {
    grid-template-columns: repeat(4, 1fr);
  }

  .content {
    padding: 24px 32px 100px;
  }
}

@media (max-width: 480px) {
  .login-container {
    padding: 1.4rem 1rem;
  }

  .login-card {
    padding: 1.5rem 1.2rem;
    border-radius: 20px;
  }

  .login-title {
    font-size: 1.7rem;
  }

  .login-logo {
    font-size: 3rem;
  }

  .top-bar {
    padding: 12px 14px 16px;
    border-radius: 0 0 22px 22px;
  }

  .hero-stat {
    padding: 7px 8px;
    gap: 6px;
  }

  .hero-stat-icon {
    font-size: 1rem;
  }

  .ask-panel {
    width: calc(100vw - 32px);
    right: 16px;
    bottom: 80px;
    height: 55vh;
  }

  #ask-btn {
    width: 50px;
    height: 50px;
    bottom: 80px;
    right: 16px;
    font-size: 22px;
  }

  .memory-grid {
    gap: 10px;
  }

  .subject-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: 10px;
  }
}

/* === 工具类 === */
.fade-in {
  animation: fadeIn 0.3s ease-out;
}

/* 错题进度提示 */
.wrong-streak-info {
  font-size: 0.75rem;
  color: var(--text-muted);
  margin-left: 4px;
}

/* 发音交互 */
.tts-clickable {
  cursor: pointer;
  border-bottom: 1px dashed var(--primary-lighter);
  transition: all 0.2s ease;
  padding: 0 1px;
  border-radius: 2px;
  display: inline;
}

.tts-clickable:hover {
  background: rgba(79,70,229,0.08);
  border-bottom-style: solid;
  border-bottom-color: var(--primary);
}

.tts-clickable:active {
  background: rgba(79,70,229,0.15);
  transform: scale(0.98);
}

.tts-clickable.speaking {
  background: rgba(79,70,229,0.12);
  border-bottom: 2px solid var(--primary);
  animation: ttsPulse 1s ease-in-out infinite;
}

@keyframes ttsPulse {
  0%, 100% { border-bottom-color: var(--primary); }
  50% { border-bottom-color: var(--primary-lighter); }
}

/* 朗读按钮 */
.read-aloud-btn {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 8px 16px;
  background: var(--gradient-primary);
  color: white;
  border: none;
  border-radius: var(--radius-full);
  font-family: var(--font-sans);
  font-size: 0.85rem;
  cursor: pointer;
  margin: 8px auto;
  box-shadow: 0 2px 8px rgba(79,70,229,0.25);
  transition: all var(--transition-slow);
}

.read-aloud-btn:hover {
  transform: scale(1.05);
  box-shadow: 0 4px 12px rgba(79,70,229,0.4);
}

.read-aloud-btn.speaking {
  background: var(--gradient-card-2);
  animation: pulse 1.5s infinite;
}

.speak-word {
  cursor: pointer;
  padding: 1px 4px;
  border-radius: 4px;
  transition: all 0.2s;
  color: var(--primary);
  font-weight: 500;
}

.speak-word:hover {
  background: rgba(79,70,229,0.08);
  text-decoration: underline;
}

.speak-char {
  display: inline-block;
  cursor: pointer;
  color: var(--danger);
  font-weight: bold;
  font-size: 1.1em;
  padding: 0 2px;
  border-bottom: 2px dashed var(--danger);
  transition: all 0.2s;
}

.speak-char:hover {
  background: var(--danger-bg);
  border-radius: 4px;
  transform: scale(1.15);
}

/* 生字拼音模式 - 填字母 */
.letter-display {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 5px;
  margin: 28px 0;
}

.letter-box {
  width: 42px;
  height: 50px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-sm);
  font-size: 1.5rem;
  font-weight: 700;
  font-family: var(--font-mono);
  text-transform: lowercase;
  transition: all 0.15s;
}

.letter-given {
  background: var(--bg-alt);
  color: var(--text-secondary);
  border-bottom: 3px solid var(--border);
  border-radius: 4px;
}

.letter-blank {
  background: transparent;
  border-bottom: 3px solid var(--border);
  border-radius: 4px;
  padding: 0;
  position: relative;
}

.letter-input-inner {
  width: 100%;
  height: 100%;
  border: none;
  background: transparent;
  font-size: 1.5rem;
  font-weight: 700;
  font-family: var(--font-mono);
  text-align: center;
  text-transform: lowercase;
  color: var(--text);
  outline: none;
}

.letter-input-inner:focus {
  background: transparent;
  border-radius: 0;
  outline: none;
}

/* === 错题本手风琴 === */
.wrong-chapter-group {
  margin-bottom: 8px;
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  overflow: hidden;
}

/* === 科目版本标签 === */
.subject-version-badge {
  display: inline-block;
  font-size: 10px;
  padding: 2px 8px;
  border-radius: 10px;
  background: var(--primary-bg);
  color: var(--primary);
  cursor: pointer;
  margin-top: auto;
  transition: all 0.2s;
  border: 1px solid transparent;
  white-space: nowrap;
  max-width: 100%;
  overflow: hidden;
  text-overflow: ellipsis;
  align-self: center;
}
.subject-version-badge:hover {
  background: var(--primary);
  color: #fff;
  border-color: var(--primary);
}

/* === 可点击版本标签 === */
.version-clickable {
  cursor: pointer;
  color: var(--primary);
  padding: 2px 8px;
  border-radius: 8px;
  transition: all 0.2s;
  white-space: nowrap;
}
.version-clickable:hover {
  background: var(--primary);
  color: #fff;
}

/* === 首次登录设置引导 === */
.setup-wizard-content {
  animation: modalSlideIn 0.25s ease-out;
}
.setup-section {
  margin-bottom: 8px;
}
.setup-version-row {
  transition: background 0.2s;
}
.setup-version-row:hover {
  background: #F9FAFB;
}

/* ========================================================
   全站设计语言铺开 v4 (2026-08-02)
   章节/学习/错题/出题/记忆/排行/我的/版本选择器
   ======================================================== */

/* ---------- 科目强调色（应用于任何带 data-subject 的容器） ---------- */
[data-subject="数学"] { --subj-bar: #6366F1; }
[data-subject="物理"] { --subj-bar: #06B6D4; }
[data-subject="生物"] { --subj-bar: #10B981; }
[data-subject="地理"] { --subj-bar: #F59E0B; }
[data-subject="历史"] { --subj-bar: #B45309; }
[data-subject="道德与法治"] { --subj-bar: #EF4444; }
[data-subject="语文"] { --subj-bar: #EC4899; }
[data-subject="英语"] { --subj-bar: #0EA5E9; }
[data-subject="化学"] { --subj-bar: #14B8A6; }

/* ---------- 页面级标题（错题/记忆/排行） ---------- */
#tab-wrong > h2,
#tab-memory > h2,
#tab-leaderboard > h2 {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 1.15rem;
  font-weight: 700;
  margin-bottom: 16px;
}
#tab-wrong > h2::before,
#tab-memory > h2::before,
#tab-leaderboard > h2::before {
  content: '';
  width: 4px;
  height: 18px;
  border-radius: 4px;
  background: var(--gradient-primary);
  flex-shrink: 0;
}

/* ---------- 章节列表页 ---------- */
.back-btn {
  background: var(--card-bg);
  border: 1.5px solid var(--border);
  border-radius: var(--radius-full);
  padding: 8px 16px;
  box-shadow: var(--shadow-sm);
  color: var(--text-secondary);
  transition: all var(--transition-base);
}
.back-btn:hover {
  border-color: var(--primary);
  color: var(--primary);
  background: var(--primary-bg);
  opacity: 1;
}

.version-tag {
  background: var(--subj-soft, var(--primary-bg));
  color: var(--subj-bar, var(--primary-dark));
  font-size: 0.78rem;
  padding: 5px 14px;
  border-radius: var(--radius-full);
  border: 1px solid transparent;
  transition: all var(--transition-base);
}

/* 单元卡：彩色顶条 + 白底卡片 */
.unit-header {
  background: var(--card-bg);
  background-image: linear-gradient(180deg, rgba(79,70,229,0.05), transparent 55%);
  color: var(--text);
  border: 1.5px solid var(--border-light);
  border-radius: var(--radius-lg);
  position: relative;
  overflow: hidden;
  box-shadow: var(--shadow-sm);
  transition: transform var(--transition-base), box-shadow var(--transition-base);
}
.unit-header::before {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 4px;
  background: var(--subj-grad, var(--gradient-primary));
}
.unit-header:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}
.unit-num {
  background: var(--subj-grad, var(--gradient-primary));
  color: #fff;
  box-shadow: 0 2px 8px var(--subj-glow, rgba(79,70,229,0.3));
}
.unit-lesson-count {
  background: var(--subj-soft, var(--primary-bg));
  color: var(--subj-bar, var(--primary-dark));
  padding: 2px 10px;
  border-radius: var(--radius-full);
  font-size: 0.7rem;
  font-weight: 600;
  white-space: nowrap;
}

/* 课文行 */
.chapter-item {
  border-radius: var(--radius-lg);
  border: 1.5px solid var(--border-light);
  box-shadow: var(--shadow-sm);
}
.chapter-item:hover {
  border-color: var(--subj-bar, var(--primary-lighter));
  box-shadow: 0 10px 24px var(--subj-glow-strong, rgba(79,70,229,0.18));
  transform: translateX(6px);
}
.chapter-num {
  background: var(--subj-grad, var(--gradient-primary));
  box-shadow: 0 3px 10px var(--subj-glow, rgba(79,70,229,0.3));
}

/* ---------- 学习内容页 ---------- */
.study-content {
  border-radius: var(--radius-xl);
  border: 1px solid var(--border-light);
  position: relative;
  overflow: hidden;
  box-shadow: var(--shadow-md);
}
.study-content::before {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 5px;
  background: var(--subj-grad, var(--gradient-primary));
}
.study-body h3 {
  border-bottom: 2px solid var(--subj-soft, var(--primary-bg));
  color: var(--subj-bar, var(--primary));
}
.study-section-title {
  border-radius: var(--radius-full);
  padding: 6px 14px;
  background: var(--subj-soft, var(--primary-bg));
  color: var(--subj-bar, var(--primary));
  font-size: 0.9rem;
}
.original-text-block {
  border-radius: var(--radius-lg);
  box-shadow: 0 6px 20px rgba(245, 158, 11, 0.12);
}

/* ---------- 错题本 ---------- */
.wrong-subject-tab.active {
  background: var(--gradient-primary);
  color: #fff;
  border-color: transparent;
  box-shadow: 0 4px 14px rgba(79,70,229,0.3);
}
.wrong-item {
  border-radius: var(--radius-lg);
  border: 1.5px solid var(--border-light);
  border-left: 4px solid var(--subj-bar, var(--primary));
  box-shadow: var(--shadow-sm);
  transition: transform var(--transition-base), box-shadow var(--transition-base);
}
.wrong-item:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-2px);
}
.wrong-item-answers .user-ans,
.wrong-item-answers .correct-ans {
  display: inline-block;
  padding: 2px 10px;
  border-radius: 8px;
}
.wrong-item-answers .user-ans { background: var(--danger-bg); }
.wrong-item-answers .correct-ans { background: var(--success-bg); }
.mastered-pill {
  display: inline-block;
  background: var(--success-bg);
  color: var(--success-text);
  font-size: 0.75rem;
  font-weight: 700;
  padding: 3px 10px;
  border-radius: var(--radius-full);
}
.master-btn {
  border-radius: var(--radius-full);
  background: linear-gradient(135deg, #10B981, #059669);
  color: #fff;
  border: none;
  padding: 7px 16px;
  box-shadow: 0 3px 10px rgba(16,185,129,0.3);
}
.master-btn:hover {
  background: linear-gradient(135deg, #34D399, #10B981);
  box-shadow: 0 5px 14px rgba(16,185,129,0.4);
}
.wrong-chapter-group {
  border: 1.5px solid var(--border-light);
  border-radius: var(--radius-lg);
  background: var(--card-bg);
  box-shadow: var(--shadow-sm);
}
.wrong-chapter-title {
  border-radius: 10px;
  background: var(--bg-alt);
}
.wrong-chapter-title:hover { background: var(--border-light); }
details[open] > .wrong-chapter-title {
  border-radius: 10px 10px 0 0;
  background: linear-gradient(135deg, var(--primary-bg), #F5F3FF);
  color: var(--primary-dark);
}
details[open] > .wrong-chapter-title::before { color: var(--primary); }
.empty-state {
  background: var(--card-bg);
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow-sm);
  border: 1.5px dashed var(--primary-lighter);
}

/* ---------- 答题页 ---------- */
.quiz-progress {
  background: var(--primary-bg);
  color: var(--primary-dark);
  padding: 4px 14px;
  border-radius: var(--radius-full);
  font-size: 0.85rem;
  font-weight: 700;
}
.question-card {
  position: relative;
  overflow: hidden;
  border-radius: var(--radius-xl);
}
.question-card::before {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 4px;
  background: var(--subj-grad, var(--gradient-primary));
}
.question-type {
  border-radius: var(--radius-full);
  padding: 5px 14px;
}
.option-btn {
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-sm);
}
.option-btn:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}
.option-btn.selected {
  border-color: var(--primary);
  background: linear-gradient(135deg, rgba(79,70,229,0.1), rgba(124,58,237,0.14));
  box-shadow: 0 0 0 3px rgba(79,70,229,0.15);
}
.feedback.correct { animation: popIn 0.35s ease; }
.feedback.wrong { animation: shakeX 0.35s ease; }
@keyframes popIn {
  0% { transform: scale(0.9); }
  60% { transform: scale(1.04); }
  100% { transform: scale(1); }
}
@keyframes shakeX {
  0%, 100% { transform: translateX(0); }
  25% { transform: translateX(-6px); }
  75% { transform: translateX(6px); }
}

/* ---------- 智能出题 ---------- */
.sq-unit-item {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 12px 14px;
  border: 2px solid var(--border);
  border-radius: var(--radius-md);
  margin-bottom: 8px;
  background: var(--card-bg);
  cursor: pointer;
  font-size: 0.9rem;
  transition: all var(--transition-base);
}
.sq-unit-item:hover {
  border-color: var(--primary-lighter);
  background: var(--primary-bg);
}
.sq-unit-item.selected {
  border-color: var(--primary);
  background: rgba(79,70,229,0.08);
  box-shadow: 0 0 0 3px rgba(79,70,229,0.1);
}
.sq-unit-item input {
  accent-color: var(--primary);
  width: 18px;
  height: 18px;
  flex-shrink: 0;
}
.sq-loading-wrap { text-align: center; padding: 50px 20px; }
.sq-loading-icon { font-size: 3rem; animation: sqFloat 1.4s ease-in-out infinite; display: inline-block; }
.sq-loading-bar {
  width: 220px;
  height: 10px;
  background: var(--border);
  border-radius: 999px;
  margin: 24px auto;
  overflow: hidden;
  position: relative;
}
.sq-loading-fill {
  height: 100%;
  width: 45%;
  border-radius: 999px;
  background: var(--gradient-primary);
  animation: sqSlide 1.2s ease-in-out infinite;
}
@keyframes sqFloat {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-8px); }
}
@keyframes sqSlide {
  0% { transform: translateX(-130%); }
  100% { transform: translateX(330%); }
}
.sq-loading-title { font-size: 1.2rem; font-weight: 700; color: var(--text); margin-bottom: 6px; }
.sq-loading-hint { color: var(--text-light); font-size: 0.9rem; }
.sq-loading-sub { color: var(--text-muted); font-size: 0.8rem; margin-top: 8px; }
.sq-fail { text-align: center; padding: 40px 20px; }
.sq-fail-icon { font-size: 3rem; margin-bottom: 12px; }
.sq-fail p { color: var(--text-light); font-size: 1.1rem; margin-bottom: 16px; }

/* ---------- 记忆训练 ---------- */
.memory-step-container { min-height: auto; padding: 20px 16px; }
.practice-header {
  background: linear-gradient(135deg, rgba(255,255,255,0.9), rgba(238,242,255,0.9));
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border: 1px solid rgba(79,70,229,0.1);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-sm);
}
.practice-back-btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 10px 18px;
  background: var(--card-bg);
  border: 1.5px solid var(--border);
  border-radius: var(--radius-full);
  color: var(--text-secondary);
  font-family: var(--font-sans);
  font-size: 0.9rem;
  font-weight: 600;
  cursor: pointer;
  transition: all var(--transition-base);
}
.practice-back-btn:hover {
  border-color: var(--primary);
  color: var(--primary);
  background: var(--primary-bg);
}
.submit-btn {
  padding: 14px 20px;
  background: var(--gradient-primary);
  color: #fff;
  border: none;
  border-radius: var(--radius-md);
  font-family: var(--font-sans);
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  box-shadow: 0 4px 14px rgba(79,70,229,0.3);
  transition: all var(--transition-base);
}
.submit-btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 20px rgba(79,70,229,0.4);
}
.options-grid {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

/* 翻卡强化 */
.flashcard-front {
  background: linear-gradient(160deg, #4F46E5 0%, #6D28D9 60%, #7C3AED 100%);
  box-shadow: 0 20px 44px rgba(79,70,229,0.35), inset 0 1px 0 rgba(255,255,255,0.25);
  position: relative;
  overflow: hidden;
}
.flashcard-front::before {
  content: '';
  position: absolute;
  top: -40px; right: -40px;
  width: 140px; height: 140px;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(255,255,255,0.2), transparent 70%);
}
.flashcard-front::after {
  content: '';
  position: absolute;
  bottom: -50px; left: -30px;
  width: 110px; height: 110px;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(196,181,253,0.3), transparent 70%);
}
.flashcard-back {
  background: linear-gradient(180deg, #fff, #F5F3FF);
  border: none;
  box-shadow: 0 20px 44px rgba(79,70,229,0.2);
}
.fc-sound-btn {
  margin-top: 14px;
  padding: 10px 22px;
  background: rgba(255,255,255,0.2);
  border: 1px solid rgba(255,255,255,0.4);
  border-radius: var(--radius-full);
  color: #fff;
  font-size: 0.9rem;
  font-family: var(--font-sans);
  cursor: pointer;
  backdrop-filter: blur(4px);
  -webkit-backdrop-filter: blur(4px);
  transition: all var(--transition-base);
}
.fc-sound-btn:hover {
  background: rgba(255,255,255,0.35);
  transform: scale(1.05);
}
.fc-word-small {
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--primary);
  margin-bottom: 8px;
}
.fc-meaning {
  font-size: 1.4rem;
  font-weight: 700;
  color: var(--text);
  line-height: 1.5;
  margin-bottom: 10px;
  text-align: center;
  word-break: break-word;
}
.fc-example {
  font-size: 0.95rem;
  color: var(--text-light);
  font-style: italic;
  text-align: center;
  line-height: 1.6;
  word-break: break-word;
}
.fc-btn {
  border-radius: var(--radius-full);
  box-shadow: var(--shadow-sm);
}
.fc-btn-red {
  background: linear-gradient(135deg, #FEE2E2, #FECACA);
  color: var(--danger);
  border: 1.5px solid rgba(239,68,68,0.25);
}
.fc-btn-green {
  background: linear-gradient(135deg, #D1FAE5, #A7F3D0);
  color: var(--success-text);
  border: 1.5px solid rgba(16,185,129,0.25);
}

/* ---------- 排行榜 ---------- */
.leaderboard-item {
  border-radius: var(--radius-lg);
  border: 1.5px solid var(--border-light);
}
.leaderboard-item.me {
  border-color: rgba(79,70,229,0.35);
  background: linear-gradient(135deg, rgba(79,70,229,0.1), rgba(124,58,237,0.08));
  box-shadow: 0 0 0 1.5px rgba(79,70,229,0.2), 0 8px 24px rgba(79,70,229,0.15);
}
.rank-num {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}
.rank-num.gold {
  background: linear-gradient(135deg, #FEF3C7, #FDE68A);
  box-shadow: 0 4px 16px rgba(245,158,11,0.4), inset 0 0 0 2px rgba(245,158,11,0.3);
  font-size: 1.4rem;
}
.rank-num.silver {
  background: linear-gradient(135deg, #F3F4F6, #E5E7EB);
  box-shadow: 0 4px 16px rgba(156,163,175,0.35), inset 0 0 0 2px rgba(156,163,175,0.35);
  font-size: 1.4rem;
}
.rank-num.bronze {
  background: linear-gradient(135deg, #FEF3C7, #FDE8C8);
  box-shadow: 0 4px 16px rgba(217,119,6,0.35), inset 0 0 0 2px rgba(217,119,6,0.3);
  font-size: 1.4rem;
}
.rank-avatar {
  width: 44px;
  height: 44px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--primary-bg);
  box-shadow: inset 0 0 0 2px rgba(79,70,229,0.12);
  font-size: 1.6rem;
  flex-shrink: 0;
}
.rank-score {
  background: var(--primary-bg);
  color: var(--primary);
  padding: 4px 12px;
  border-radius: var(--radius-full);
  font-size: 1rem;
  white-space: nowrap;
}

/* ---------- 我的 ---------- */
.profile-card::after {
  content: '';
  position: absolute;
  top: -50px; right: -40px;
  width: 170px; height: 170px;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(255,255,255,0.15), transparent 70%);
  pointer-events: none;
}
.profile-avatar {
  width: 92px;
  height: 92px;
  margin: 0 auto 14px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(255,255,255,0.2);
  border: 3px solid rgba(255,255,255,0.5);
  border-radius: 50%;
  box-shadow: 0 8px 24px rgba(0,0,0,0.18);
  font-size: 3.2rem;
  filter: drop-shadow(0 4px 10px rgba(0,0,0,0.2));
}
.stat-card {
  border-radius: var(--radius-lg);
  border: 1.5px solid var(--border-light);
  position: relative;
  overflow: hidden;
}
.stat-card::before {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 3px;
  background: var(--gradient-primary);
  opacity: 0.6;
}
.stat-value {
  background: var(--gradient-primary);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  color: transparent;
}

/* ---------- 版本选择器 ---------- */
#version-picker-modal .modal-content,
#version-search-modal .modal-content {
  border-radius: 24px;
  border: 1px solid rgba(79,70,229,0.1);
  box-shadow: var(--shadow-xl);
}
#taxonomy-tree .unit-header {
  margin-bottom: 8px;
}
.vp-version {
  border-radius: var(--radius-md) !important;
  margin-bottom: 4px !important;
  font-size: 13.5px !important;
  transition: all var(--transition-fast);
}
.vs-query-input {
  flex: 1;
  padding: 12px 16px;
  border: 2px solid var(--border) !important;
  border-radius: var(--radius-md) !important;
  font-size: 14px;
  font-family: var(--font-sans);
  outline: none;
  box-sizing: border-box;
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
}
.vs-query-input:focus {
  border-color: var(--primary) !important;
  box-shadow: 0 0 0 4px rgba(79,70,229,0.12);
}

/* ---------- 加载状态卡片 ---------- */
.loading-box {
  background: var(--card-bg);
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow-sm);
  margin: 12px 0;
  border: 1px solid var(--border-light);
}

/* 版本识别样章卡（章节页引导） */
#chapter-list .unit-header {
  cursor: pointer;
  margin-bottom: 8px;
}
#chapter-list .unit-header:hover {
  transform: translateY(-2px);
  box-shadow: var(--subj-glow-strong, rgba(79,70,229,0.18)) 0 10px 24px;
}

/* === 我的页·功能入口行（排行榜等） === */
.profile-entry {
  display: flex;
  justify-content: space-between;
  align-items: center;
  width: 100%;
  max-width: 320px;
  margin: 14px auto 0;
  padding: 14px 18px;
  background: #fff;
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  font-size: 15px;
  font-weight: 600;
  color: #374151;
  cursor: pointer;
  transition: all 0.2s;
}
.profile-entry:hover {
  border-color: var(--primary);
  color: var(--primary);
  box-shadow: 0 4px 14px rgba(79,70,229,0.12);
}