/* =========================================================
   魔方小课堂 · 复古牛皮纸手绘风格
   配色取自 Cubing.js 标准魔方色 + 牛皮纸底色
   ========================================================= */

:root {
  /* —— 牛皮纸底色系 —— */
  --paper-light: #f6ecd2;   /* 高亮纸面 */
  --paper: #ecdcb4;         /* 主纸面 */
  --paper-dark: #dcc79a;    /* 阴影纸面 */
  --paper-edge: #c2a978;    /* 纸张边缘 */
  --ink: #4a3520;           /* 主墨色（深棕） */
  --ink-soft: #6e5638;      /* 次墨色 */
  --ink-faint: #9c8362;     /* 浅墨色 */

  /* —— Cubing.js 魔方配色（作为点缀色） —— */
  --cube-yellow: #ffd23f;   /* D 黄面 */
  --cube-red: #d6453a;      /* R 红面 */
  --cube-green: #4ea84e;    /* F 绿面 */
  --cube-blue: #3d6fb5;     /* B 蓝面 */
  --cube-orange: #ef8b34;   /* L 橙面 */
  --cube-white: #faf6ea;    /* U 白面 */

  --radius: 14px;
  --shadow: 5px 6px 0 var(--ink-soft);
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: "ZCOOL KuaiLe", "PingFang SC", "Microsoft YaHei", sans-serif;
  color: var(--ink);
  background-color: var(--paper);
  /* 牛皮纸底纹：径向渐变制造不规则色斑 */
  background-image:
    radial-gradient(ellipse at 20% 15%, rgba(255, 245, 210, 0.6), transparent 55%),
    radial-gradient(ellipse at 80% 80%, rgba(194, 169, 120, 0.4), transparent 55%),
    radial-gradient(ellipse at 60% 30%, rgba(120, 90, 50, 0.08), transparent 60%);
  min-height: 100vh;
  line-height: 1.6;
  overflow-x: hidden;
}

/* 纸张颗粒纹理叠加 */
.paper-grain {
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: 1;
  opacity: 0.5;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='300' height='300'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.75' numOctaves='3' stitchTiles='stitch'/%3E%3CfeColorMatrix values='0 0 0 0 0.3 0 0 0 0 0.21 0 0 0 0 0.12 0 0 0 0.13 0'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)'/%3E%3C/svg%3E");
}

/* ============ 页面切换 ============ */
.page {
  display: none;
  position: relative;
  z-index: 2;
  max-width: 1100px;
  margin: 0 auto;
  padding: 28px 24px 60px;
  animation: pageIn 0.4s ease;
}
.page.active {
  display: block;
}
@keyframes pageIn {
  from { opacity: 0; transform: translateY(12px); }
  to   { opacity: 1; transform: translateY(0); }
}

/* ============ 首页 · 现代卡片风格 ============ */
.home-page {
  max-width: 1120px;
  padding: 20px 28px 60px;
}

/* —— 顶部导航 —— */
.top-nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 8px 0 24px;
  border-bottom: 2px dashed var(--paper-edge);
  margin-bottom: 28px;
}
.nav-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-family: "Ma Shan Zheng", sans-serif;
  font-size: 26px;
  color: var(--ink);
}
.logo-dot {
  display: inline-block;
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background: var(--cube-red);
  border: 2px solid var(--ink);
}
.nav-links {
  display: flex;
  gap: 28px;
}
.nav-link {
  font-size: 17px;
  color: var(--ink-soft);
  cursor: pointer;
  padding: 4px 2px;
  border-bottom: 2px solid transparent;
  transition: all 0.15s ease;
  text-decoration: none;
}
.nav-link:hover {
  color: var(--ink);
  border-color: var(--paper-edge);
}
.nav-link.active {
  color: var(--ink);
  border-color: var(--ink);
}
/* —— Hero 区 —— */
.hero {
  display: grid;
  grid-template-columns: 1.4fr 1fr;
  gap: 32px;
  align-items: end;
  margin-bottom: 36px;
}
.hero-tag {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: var(--cube-white);
  border: 2px solid var(--ink);
  border-radius: 24px;
  padding: 6px 16px;
  font-size: 14px;
  color: var(--ink);
  margin-bottom: 18px;
}
.tag-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--cube-green);
}
.hero-title {
  font-family: "Ma Shan Zheng", sans-serif;
  font-size: 52px;
  line-height: 1.15;
  color: var(--ink);
  letter-spacing: 2px;
}
.title-highlight {
  color: var(--cube-red);
  position: relative;
  display: inline-block;
}
.title-highlight::after {
  content: "";
  position: absolute;
  left: -4px;
  right: -4px;
  bottom: 2px;
  height: 14px;
  background: var(--cube-yellow);
  opacity: 0.5;
  z-index: -1;
  border-radius: 4px;
  transform: skewX(-4deg);
}
.hero-right {
  padding-bottom: 12px;
}
.hero-right p {
  font-size: 17px;
  color: var(--ink-soft);
  line-height: 1.8;
}
.hero-right b {
  color: var(--ink);
}

/* —— 卡片网格 —— */
.card-grid {
  display: grid;
  grid-template-columns: 1.5fr 1fr;
  gap: 24px;
  align-items: stretch;
}
.lab-column {
  display: grid;
  grid-template-rows: repeat(4, 1fr);
  gap: 24px;
}

/* 卡片通用样式 */
.lab-card {
  font-family: inherit;
  cursor: pointer;
  border: 3.5px solid var(--ink);
  border-radius: 20px;
  padding: 24px;
  text-align: left;
  box-shadow: 5px 6px 0 var(--ink-soft);
  transition: transform 0.15s ease, box-shadow 0.15s ease;
  display: flex;
  flex-direction: column;
  gap: 12px;
  position: relative;
  overflow: hidden;
}
.lab-card:hover {
  transform: translateY(-5px);
  box-shadow: 7px 10px 0 var(--ink);
}
.lab-tag {
  font-size: 13px;
  letter-spacing: 1.5px;
  color: var(--ink-soft);
  font-weight: 600;
}

/* 黄色大卡片 */
.lab-yellow {
  background: var(--cube-yellow);
  min-height: 620px;
}
.lab-main {
  grid-row: span 4;
}
.lab-content {
  display: grid;
  grid-template-columns: 1fr 220px;
  gap: 16px;
  flex: 1;
  align-items: end;
}
.lab-text {
  display: flex;
  flex-direction: column;
  gap: 10px;
}
.lab-title {
  font-family: "Ma Shan Zheng", sans-serif;
  font-size: 30px;
  color: var(--ink);
  line-height: 1.3;
}
.lab-title-sm {
  font-family: "Ma Shan Zheng", sans-serif;
  font-size: 24px;
  color: var(--ink);
  line-height: 1.35;
}
.lab-desc {
  font-size: 15px;
  color: var(--ink-soft);
  line-height: 1.7;
}
.lab-action {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-top: auto;
  font-size: 15px;
  color: var(--ink);
  font-weight: 600;
  padding: 10px 16px;
  background: rgba(255, 255, 255, 0.5);
  border: 2px solid var(--ink);
  border-radius: 30px;
  align-self: flex-start;
}
.lab-action .arrow {
  transition: transform 0.15s ease;
}
.lab-card:hover .lab-action .arrow {
  transform: translateX(4px);
}
.lab-cube {
  display: flex;
  align-items: center;
  justify-content: center;
}
.lab-cube twisty-player {
  width: 200px;
  height: 240px;
  border: 3px solid var(--ink);
  border-radius: 14px;
  box-shadow: 4px 4px 0 var(--ink-soft);
  background: var(--cube-white);
}

/* 粉色卡片 */
.lab-pink {
  background: #f7c5d0;
}

/* 蓝色卡片 */
.lab-blue {
  background: #a8c8f0;
}

.lab-mint {
  background: #aee0cf;
}

/* —— twisty-player 通用样式 —— */
twisty-player {
  border-radius: 12px;
  overflow: hidden;
}

.home-footer {
  text-align: center;
  margin-top: 30px;
  font-size: 15px;
  color: var(--ink-faint);
}

/* ============ 通用：返回按钮 / 页头 ============ */
.back-btn {
  font-family: inherit;
  font-size: 18px;
  cursor: pointer;
  color: var(--ink);
  background: var(--paper-light);
  border: 3px solid var(--ink);
  border-radius: 30px;
  padding: 7px 20px;
  box-shadow: 3px 3px 0 var(--ink-soft);
  transition: transform 0.12s ease;
}
.back-btn:hover { transform: translate(-2px, -2px); }
.back-btn:active { transform: translate(1px, 1px); box-shadow: 1px 1px 0 var(--ink-soft); }

.page-header {
  text-align: center;
  margin: 18px auto 10px;
}
.page-title {
  font-family: "Ma Shan Zheng", "ZCOOL KuaiLe", sans-serif;
  font-size: 48px;
  color: var(--cube-red);
  letter-spacing: 4px;
  text-shadow: 3px 3px 0 var(--paper-dark);
}
.page-sub {
  margin-top: 4px;
  font-size: 19px;
  color: var(--ink-soft);
}

/* ============ 教程目录页 ============ */
.tutorial-cube-wrap {
  display: flex;
  justify-content: center;
  margin: 10px auto 20px;
}
#tutorial-cube {
  width: 260px;
  height: 340px;
  max-width: 100%;
  border: 3px solid var(--ink);
  border-radius: 12px;
  box-shadow: var(--shadow);
  background: var(--paper-light);
}

.lessons {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 24px;
  margin-top: 10px;
}
.lesson-card {
  --accent: var(--cube-green);
  background: var(--paper-light);
  border: 3.5px solid var(--ink);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 20px 22px 22px;
  position: relative;
  transform: rotate(-0.5deg);
  transition: transform 0.15s ease;
}
.lesson-card:nth-child(2) { transform: rotate(0.6deg); }
.lesson-card:nth-child(3) { transform: rotate(-0.4deg); }
.lesson-card:hover { transform: rotate(0deg) translateY(-4px); }
.lesson-card::before {           /* 课程顶部彩条 */
  content: "";
  position: absolute;
  top: 0;
  left: 14px;
  right: 14px;
  height: 8px;
  background: var(--accent);
  border-radius: 0 0 6px 6px;
}
.lesson-num {
  position: absolute;
  top: 14px;
  right: 18px;
  font-family: "Ma Shan Zheng", sans-serif;
  font-size: 40px;
  color: var(--accent);
  opacity: 0.5;
  line-height: 1;
}
.lesson-title {
  font-size: 26px;
  color: var(--ink);
  margin-bottom: 12px;
  padding-right: 40px;
}
.lesson-list {
  list-style: none;
}
.lesson-list li {
  font-size: 18px;
  color: var(--ink-soft);
  padding: 8px 10px;
  margin-bottom: 6px;
  border-bottom: 2px dashed var(--paper-edge);
  display: flex;
  align-items: baseline;
  gap: 10px;
}
.lesson-list li:last-child { border-bottom: none; }
.li-no {
  font-family: "Ma Shan Zheng", sans-serif;
  font-size: 20px;
  color: var(--accent);
  flex-shrink: 0;
}

/* ============ 竞速模式（新版布局） ============ */
.speed-page {
  min-height: calc(100vh - 40px);
}

.speed-layout {
  display: grid;
  grid-template-columns: 1fr 280px;
  grid-template-rows: auto 1fr;
  gap: 20px;
  max-width: 960px;
  margin: 10px auto 0;
  padding: 0 20px;
}

/* 顶部：打乱文字区域（跨两列） */
.speed-scramble-area {
  grid-column: 1 / -1;
  background: var(--paper-light);
  border: 3px solid var(--ink);
  border-radius: 18px;
  padding: 18px 24px;
  box-shadow: 4px 5px 0 var(--ink-soft);
  text-align: center;
  min-height: 90px;
  display: flex;
  flex-direction: column;
  justify-content: center;
}
.scramble-cn {
  font-size: 18px;
  font-weight: 700;
  color: var(--ink);
  letter-spacing: 1px;
  margin-bottom: 6px;
  line-height: 1.4;
  word-break: break-all;
}
.scramble-en {
  font-size: 16px;
  font-family: "Courier New", monospace;
  color: var(--ink-soft);
  letter-spacing: 2px;
  word-break: break-all;
  line-height: 1.5;
  min-height: 22px;
}

/* 中心：计时 */
.speed-timer-area {
  grid-row: 2;
  background: var(--paper-light);
  border: 4px solid var(--ink);
  border-radius: 22px;
  padding: 40px 30px;
  box-shadow: 5px 6px 0 var(--ink-soft);
  text-align: center;
  display: flex;
  flex-direction: column;
  justify-content: center;
  min-height: 340px;
}
.speed-timer-display {
  font-family: "Courier New", monospace;
  font-size: 96px;
  font-weight: bold;
  color: var(--ink);
  letter-spacing: 2px;
  line-height: 1;
  font-variant-numeric: tabular-nums;
  transition: color 0.2s ease;
}
.speed-timer-area.inspecting .speed-timer-display {
  color: var(--cube-orange);
}
.speed-timer-area.running .speed-timer-display {
  color: var(--cube-green);
}
.speed-timer-area.finished .speed-timer-display {
  color: var(--cube-red);
}
.speed-timer-status {
  font-size: 20px;
  color: var(--ink-soft);
  margin-top: 18px;
  min-height: 28px;
}

/* 左下：五连统计 */
.speed-solves-area {
  background: var(--paper-light);
  border: 3px solid var(--ink);
  border-radius: 18px;
  padding: 18px 20px;
  box-shadow: 4px 5px 0 var(--ink-soft);
  display: flex;
  flex-direction: column;
  gap: 10px;
}
.speed-solves-title {
  font-size: 18px;
  font-weight: 700;
  color: var(--ink);
  margin-bottom: 2px;
}
.speed-solves-list {
  flex: 1;
  overflow-y: auto;
  background: var(--paper);
  border: 2px solid var(--ink);
  border-radius: 12px;
  padding: 10px 14px;
  min-height: 160px;
  max-height: 200px;
}
.speed-solves-empty {
  color: var(--ink-faint);
  font-style: italic;
  font-size: 14px;
  text-align: center;
  margin-top: 30px;
}
.speed-solve-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 4px 0;
  font-size: 14px;
  color: var(--ink);
  border-bottom: 1.5px dashed var(--ink-faint);
}
.speed-solve-row:last-child {
  border-bottom: none;
}
.speed-solve-num {
  font-weight: 700;
  color: var(--ink-soft);
  min-width: 36px;
}
.speed-solve-time {
  font-family: "Courier New", monospace;
  font-weight: bold;
  font-size: 15px;
}
.speed-solve-time.best {
  color: var(--cube-green);
}
.speed-solve-time.worst {
  color: var(--cube-red);
}
.speed-average {
  display: flex;
  align-items: center;
  justify-content: space-between;
  background: var(--cube-yellow);
  border: 2.5px solid var(--ink);
  border-radius: 12px;
  padding: 10px 14px;
  box-shadow: 2px 2px 0 var(--ink-soft);
}
.speed-avg-label {
  font-size: 15px;
  font-weight: 700;
  color: var(--ink);
}
.speed-avg-value {
  font-family: "Courier New", monospace;
  font-size: 20px;
  font-weight: bold;
  color: var(--cube-red);
}
.speed-clear-btn {
  width: 100%;
  padding: 8px;
  border: 2px solid var(--ink);
  border-radius: 10px;
  background: #f7c5d0;
  font-size: 13px;
  font-weight: 700;
  color: var(--ink);
  cursor: pointer;
  transition: transform 0.15s ease;
  box-shadow: 2px 2px 0 var(--ink-soft);
}
.speed-clear-btn:hover {
  transform: translateY(-1px);
  box-shadow: 3px 3px 0 var(--ink-soft);
}

/* 右下：打乱魔方 */
.speed-cube-area {
  background: var(--paper-light);
  border: 3px solid var(--ink);
  border-radius: 18px;
  padding: 16px;
  box-shadow: 4px 5px 0 var(--ink-soft);
  display: flex;
  align-items: center;
  justify-content: center;
}
.speed-cube-area twisty-player {
  width: 100%;
  height: 240px;
}

/* 响应式 */
@media (max-width: 820px) {
  .speed-layout {
    grid-template-columns: 1fr;
  }
  .speed-timer-display {
    font-size: 68px;
  }
  .speed-timer-area {
    min-height: 260px;
  }
  .speed-cube-area twisty-player {
    height: 200px;
  }
}

/* ============ 闯关模式：敬请期待 ============ */
.coming-soon {
  max-width: 560px;
  margin: 40px auto;
  background: var(--paper-light);
  border: 4px solid var(--ink);
  border-radius: 22px;
  box-shadow: var(--shadow);
  padding: 50px 24px 44px;
  text-align: center;
  position: relative;
  transform: rotate(0.8deg);
}
.cs-tape {
  position: absolute;
  top: -18px;
  left: 50%;
  transform: translateX(-50%) rotate(-2deg);
  background: var(--cube-red);
  color: var(--cube-white);
  font-size: 24px;
  letter-spacing: 4px;
  padding: 6px 30px;
  border: 2px solid var(--ink);
  border-radius: 4px;
  box-shadow: 2px 2px 0 var(--ink-soft);
}
/* CSS 画的小魔方装饰 */
.cs-cube-deco {
  position: relative;
  width: 130px;
  height: 130px;
  margin: 16px auto 22px;
  perspective: 400px;
}
.cs-cube-deco .face {
  position: absolute;
  width: 80px;
  height: 80px;
  border: 3px solid var(--ink);
  border-radius: 8px;
  box-shadow: inset 0 0 0 4px rgba(255, 255, 255, 0.15);
}
.f-top {
  background: var(--cube-yellow);
  transform: rotateX(90deg) translateZ(40px) rotate(-12deg);
  top: 6px; left: 25px;
  animation: bob 3s ease-in-out infinite;
}
.f-front {
  background: var(--cube-red);
  top: 40px; left: 10px;
  transform: skewY(-12deg);
  animation: bob 3s ease-in-out infinite 0.2s;
}
.f-right {
  background: var(--cube-green);
  top: 40px; left: 70px;
  transform: skewX(-12deg);
  animation: bob 3s ease-in-out infinite 0.4s;
}
@keyframes bob {
  0%, 100% { transform-origin: center; }
  50% { filter: brightness(1.08); }
}
.cs-text {
  font-size: 26px;
  color: var(--ink);
  margin-bottom: 8px;
}
.cs-sub {
  font-size: 18px;
  color: var(--ink-soft);
}

/* ============ 课程卡片可点击 ============ */
.lesson-card.clickable {
  cursor: pointer;
}
.lesson-card.clickable:hover {
  transform: rotate(0deg) translateY(-6px);
  box-shadow: 7px 9px 0 var(--ink);
}
.lesson-enter {
  margin-top: 10px;
  text-align: center;
  font-size: 17px;
  color: var(--accent);
  background: var(--cube-white);
  border: 2px dashed var(--accent);
  border-radius: 30px;
  padding: 4px 16px;
  display: inline-block;
}

/* ============ 课程详情页（左右两栏布局） ============ */
.lesson-page {
  max-width: 1200px;
}

.lesson-layout {
  display: grid;
  grid-template-columns: 240px 1fr;
  gap: 24px;
  margin-top: 10px;
  align-items: start;
}

/* —— 左侧边栏 —— */
.lesson-sidebar {
  position: sticky;
  top: 20px;
  background: var(--paper-light);
  border: 3.5px solid var(--ink);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 18px 14px;
  transform: rotate(-0.4deg);
}
.ls-header {
  display: flex;
  align-items: center;
  gap: 10px;
  padding-bottom: 12px;
  border-bottom: 2px dashed var(--paper-edge);
  margin-bottom: 12px;
}
.ls-num {
  font-family: "Ma Shan Zheng", sans-serif;
  font-size: 44px;
  color: var(--cube-green);
  line-height: 1;
  opacity: 0.7;
}
.ls-title {
  font-size: 20px;
  color: var(--ink);
  line-height: 1.4;
}
.ls-progress {
  margin-bottom: 14px;
}
.ls-progress-label {
  font-size: 14px;
  color: var(--ink-faint);
}
.ls-progress-bar {
  margin-top: 4px;
  height: 10px;
  background: var(--paper-dark);
  border: 2px solid var(--ink);
  border-radius: 6px;
  overflow: hidden;
}
.ls-progress-fill {
  height: 100%;
  width: 33%;
  background: var(--cube-green);
  transition: width 0.3s ease;
}
.ls-nav {
  display: flex;
  flex-direction: column;
  gap: 6px;
}
.ls-item {
  font-family: inherit;
  cursor: pointer;
  display: flex;
  align-items: flex-start;
  gap: 10px;
  text-align: left;
  padding: 10px 12px;
  background: transparent;
  border: 2px solid transparent;
  border-radius: 10px;
  color: var(--ink-soft);
  transition: all 0.15s ease;
  font-size: 15px;
  line-height: 1.3;
}
.ls-item:hover {
  background: var(--paper);
  border-color: var(--paper-edge);
  color: var(--ink);
}
.ls-item.active {
  background: var(--cube-green);
  color: var(--cube-white);
  border-color: var(--ink);
  box-shadow: 3px 3px 0 var(--ink-soft);
}
.ls-item-no {
  font-family: "Ma Shan Zheng", sans-serif;
  font-size: 22px;
  flex-shrink: 0;
  width: 40px;
}
.ls-item-text {
  flex: 1;
}

/* —— 右侧内容区 —— */
.lesson-content {
  background: var(--paper-light);
  border: 3.5px solid var(--ink);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 32px 36px 28px;
  min-height: 500px;
}
.ls-section {
  animation: fadeSlide 0.35s ease;
}
.ls-section.hidden {
  display: none;
}
@keyframes fadeSlide {
  from { opacity: 0; transform: translateY(10px); }
  to   { opacity: 1; transform: translateY(0); }
}
.ls-section-tag {
  display: inline-block;
  font-family: "Ma Shan Zheng", sans-serif;
  font-size: 16px;
  color: var(--cube-white);
  background: var(--cube-green);
  padding: 3px 14px;
  border: 2px solid var(--ink);
  border-radius: 4px;
  margin-bottom: 10px;
  box-shadow: 2px 2px 0 var(--ink-soft);
}
.ls-section-title {
  font-family: "Ma Shan Zheng", sans-serif;
  font-size: 36px;
  color: var(--ink);
  margin-bottom: 24px;
  letter-spacing: 2px;
}

/* 1.1 内容：文字 + 魔方并排 */
.ls-section-body {
  display: grid;
  grid-template-columns: 1fr 280px;
  gap: 28px;
  align-items: start;
}
.ls-text p {
  font-size: 18px;
  color: var(--ink-soft);
  margin-bottom: 14px;
  line-height: 1.8;
}
.ls-text b {
  color: var(--ink);
}
.ls-fun-fact {
  margin-top: 18px;
  padding: 12px 16px;
  background: var(--cube-yellow);
  border: 2px dashed var(--ink);
  border-radius: 10px;
  font-size: 16px;
  color: var(--ink);
  display: flex;
  align-items: flex-start;
  gap: 10px;
}
.fun-icon {
  font-size: 22px;
  flex-shrink: 0;
}

/* 挑战卡片 - 可点击查看答案 */
.challenge-card {
  cursor: pointer;
  transition: transform 0.15s ease, box-shadow 0.15s ease;
  user-select: none;
}
.challenge-card:hover {
  transform: translateY(-2px);
  box-shadow: 3px 3px 0 var(--ink-soft);
}
.challenge-card .challenge-hint {
  font-size: 13px;
  color: var(--cube-red);
  font-weight: bold;
  margin-left: auto;
  white-space: nowrap;
}
.challenge-card.opened .challenge-hint {
  display: none;
}
.challenge-answer {
  display: none;
  margin-top: 8px;
  padding: 14px 18px;
  background: #fff8e1;
  border: 2px solid var(--ink);
  border-radius: 12px;
  font-size: 15px;
  line-height: 1.6;
  color: var(--ink);
  animation: answerPop 0.3s ease;
}
.challenge-answer.show {
  display: block;
}
@keyframes answerPop {
  from { opacity: 0; transform: translateY(-8px); }
  to   { opacity: 1; transform: translateY(0); }
}
.ls-cube-wrap {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
}
.ls-cube-wrap.center {
  margin: 20px auto 0;
}
.ls-cube-wrap twisty-player {
  width: 260px;
  height: 320px;
  max-width: 100%;
  border: 3px solid var(--ink);
  border-radius: 12px;
  box-shadow: 4px 4px 0 var(--ink-soft);
  background: var(--cube-white);
}
.ls-cube-label {
  font-size: 15px;
  color: var(--ink-faint);
  text-align: center;
}

/* 1.2 魔方网格 */
.ls-compare-list {
  list-style: none;
  padding: 0;
  margin: 10px 0;
}
.ls-compare-list li {
  font-size: 17px;
  color: var(--ink-soft);
  padding: 10px 14px;
  margin-bottom: 8px;
  background: var(--paper);
  border-left: 5px solid var(--cube-green);
  border-radius: 6px;
}
.ls-compare-list b {
  color: var(--cube-green);
  font-family: "Ma Shan Zheng", sans-serif;
  font-size: 20px;
}
.ls-cube-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 18px;
  margin-top: 24px;
}
.ls-cube-grid-item {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 6px;
}
.ls-cube-grid-item twisty-player {
  width: 100%;
  max-width: 160px;
  height: 190px;
  border: 2.5px solid var(--ink);
  border-radius: 10px;
  box-shadow: 3px 3px 0 var(--ink-soft);
  background: var(--cube-white);
}
.ls-cube-name {
  font-family: "Ma Shan Zheng", sans-serif;
  font-size: 22px;
  color: var(--ink);
}
.ls-cube-wr {
  display: block;
  text-align: center;
  font-size: 13px;
  color: var(--cube-red);
  margin-top: 4px;
  font-weight: 500;
  font-family: "Noto Sans SC", sans-serif;
}
.ls-cube-wr b {
  font-size: 15px;
  color: var(--ink);
}
.ls-cube-wr.wr-clickable {
  cursor: pointer;
  transition: all 0.15s ease;
  text-decoration: none;
}
.ls-cube-wr.wr-clickable:hover {
  color: var(--cube-red);
  text-shadow: 1px 1px 0 var(--cube-yellow);
  transform: scale(1.05);
}

/* 视频弹窗 */
.video-modal {
  display: none;
  position: fixed;
  top: 0; left: 0; right: 0; bottom: 0;
  z-index: 9999;
  align-items: center;
  justify-content: center;
}
.video-modal.show {
  display: flex;
}
.video-modal-bg {
  position: absolute;
  top: 0; left: 0; right: 0; bottom: 0;
  background: rgba(0, 0, 0, 0.75);
}
.video-modal-box {
  position: relative;
  background: var(--cube-yellow);
  border: 3px solid var(--ink);
  border-radius: 18px;
  padding: 20px;
  box-shadow: 6px 8px 0 var(--ink-soft);
  max-width: 90vw;
  width: 720px;
}
.video-close {
  position: absolute;
  top: -15px; right: -15px;
  width: 38px; height: 38px;
  border-radius: 50%;
  background: var(--cube-red);
  color: white;
  border: 2px solid var(--ink);
  font-size: 18px;
  font-weight: bold;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  line-height: 1;
}
.video-close:hover {
  transform: rotate(90deg);
  transition: transform 0.2s;
}
.video-frame-wrap {
  position: relative;
  width: 100%;
  padding-bottom: 56.25%;
  height: 0;
  overflow: hidden;
  border-radius: 10px;
  border: 2px solid var(--ink);
}
.video-frame-wrap iframe {
  position: absolute;
  top: 0; left: 0;
  width: 100%;
  height: 100%;
  border: none;
}
.video-title {
  margin-top: 14px;
  text-align: center;
  font-size: 15px;
  font-weight: bold;
  color: var(--ink);
  font-family: "Noto Sans SC", sans-serif;
}
.ls-cube-hint {
  text-align: center;
  margin-top: 16px;
  font-size: 15px;
  color: var(--ink-faint);
}

/* 1.3 块类型说明 */
.ls-piece-types {
  display: flex;
  flex-direction: column;
  gap: 14px;
  margin: 14px 0;
}
.ls-piece-type {
  display: flex;
  gap: 16px;
  align-items: flex-start;
  padding: 14px 16px;
  background: var(--paper);
  border: 2px solid var(--paper-edge);
  border-radius: 12px;
}
.ls-piece-icon {
  width: 80px;
  height: 80px;
  flex-shrink: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 3px;
  border-radius: 10px;
  border: 2.5px solid var(--ink);
}
.ls-piece-icon span {
  display: block;
  border-radius: 4px;
  border: 1.5px solid var(--ink);
}
.piece-center {
  background: var(--cube-yellow);
}
.piece-center span {
  width: 48px;
  height: 48px;
  background: var(--cube-white);
}
.piece-edge {
  background: var(--cube-green);
  flex-wrap: wrap;
  gap: 0;
  padding: 6px;
}
.piece-edge span {
  width: 30px;
  height: 30px;
  background: var(--cube-white);
  margin: 1px;
}
.piece-edge span:last-child {
  background: var(--cube-yellow);
}
.piece-corner {
  background: var(--cube-red);
  flex-wrap: wrap;
  padding: 5px;
  gap: 0;
}
.piece-corner span {
  width: 28px;
  height: 28px;
  margin: 2px;
}
.piece-corner span:nth-child(1) { background: var(--cube-white); }
.piece-corner span:nth-child(2) { background: var(--cube-yellow); }
.piece-corner span:nth-child(3) { background: var(--cube-green); }
.ls-piece-info h4 {
  font-size: 20px;
  color: var(--ink);
  margin-bottom: 4px;
}
.ls-piece-info p {
  font-size: 16px;
  color: var(--ink-soft);
  margin: 0;
}

/* —— 底部导航按钮 —— */
.ls-bottom-nav {
  display: flex;
  justify-content: space-between;
  margin-top: 28px;
  padding-top: 20px;
  border-top: 2px dashed var(--paper-edge);
}
.ls-nav-btn {
  font-family: inherit;
  font-size: 18px;
  cursor: pointer;
  padding: 8px 22px;
  border-radius: 30px;
  border: 3px solid var(--ink);
  background: var(--paper-light);
  color: var(--ink);
  box-shadow: 3px 3px 0 var(--ink-soft);
  transition: all 0.12s ease;
}
.ls-nav-btn:hover:not(:disabled) {
  transform: translate(-2px, -2px);
  box-shadow: 5px 5px 0 var(--ink-soft);
}
.ls-nav-btn:active:not(:disabled) {
  transform: translate(1px, 1px);
  box-shadow: 1px 1px 0 var(--ink-soft);
}
.ls-nav-btn:disabled {
  opacity: 0.4;
  cursor: not-allowed;
  background: var(--paper-dark);
}
.ls-nav-btn#ls1-next:not(:disabled) {
  background: var(--cube-green);
  color: var(--cube-white);
}

/* ============ 第二课：动词卡片 ============ */
.ls-move-intro {
  display: flex;
  flex-direction: column;
  gap: 10px;
  margin: 14px 0;
}
.ls-move-row {
  display: flex;
  gap: 12px;
}
.ls-move-cell {
  flex: 1;
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 12px 14px;
  background: var(--paper);
  border: 2.5px solid var(--ink);
  border-radius: 12px;
  box-shadow: 3px 3px 0 var(--ink-soft);
}
.move-char {
  font-family: "Ma Shan Zheng", sans-serif;
  font-size: 34px;
  color: var(--cube-orange);
  line-height: 1;
  width: 50px;
  text-align: center;
  flex-shrink: 0;
}
.move-desc {
  font-size: 15px;
  color: var(--ink-soft);
  line-height: 1.5;
}

.ls-move-detail {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
  margin: 16px 0;
}
.ls-move-card {
  background: var(--paper);
  border: 2.5px solid var(--ink);
  border-radius: 14px;
  padding: 16px 18px;
  box-shadow: 4px 4px 0 var(--ink-soft);
}
.ls-move-name {
  display: flex;
  align-items: baseline;
  gap: 12px;
  margin-bottom: 10px;
  padding-bottom: 8px;
  border-bottom: 2px dashed var(--paper-edge);
}
.move-big {
  font-family: "Ma Shan Zheng", sans-serif;
  font-size: 42px;
  color: var(--cube-orange);
  line-height: 1;
}
.move-en {
  font-family: "Courier New", monospace;
  font-size: 22px;
  font-weight: bold;
  color: var(--ink-faint);
  background: var(--paper-dark);
  padding: 2px 10px;
  border-radius: 6px;
  border: 1.5px solid var(--ink);
}
.ls-move-card p {
  font-size: 15px;
  color: var(--ink-soft);
  line-height: 1.7;
  margin: 4px 0;
}
.ls-move-card p b {
  color: var(--ink);
}

/* 可点击的动词卡片 */
.move-clickable {
  cursor: pointer;
  transition: transform 0.15s ease, box-shadow 0.15s ease, border-color 0.15s ease;
}
.move-clickable:hover {
  transform: translateY(-3px);
  box-shadow: 6px 7px 0 var(--ink-soft);
  border-color: var(--cube-orange);
}
.move-clickable.playing {
  background: var(--cube-yellow);
  border-color: var(--cube-red);
  animation: pulseCard 0.6s ease infinite alternate;
}
@keyframes pulseCard {
  from { box-shadow: 4px 4px 0 var(--ink-soft); }
  to   { box-shadow: 4px 4px 0 var(--cube-red); }
}

/* ============ 第三课：流程步骤 ============ */
.ls-flow-steps {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  margin: 18px 0;
  flex-wrap: wrap;
}
.ls-flow-step {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 4px;
  padding: 10px 14px;
  background: var(--paper);
  border: 2.5px solid var(--ink);
  border-radius: 12px;
  box-shadow: 3px 3px 0 var(--ink-soft);
  text-align: center;
  min-width: 100px;
}
.flow-num {
  font-family: "Ma Shan Zheng", sans-serif;
  font-size: 32px;
  color: var(--cube-blue);
  line-height: 1;
}
.flow-text {
  font-size: 14px;
  color: var(--ink);
  line-height: 1.3;
}
.flow-text small {
  color: var(--ink-faint);
  font-size: 12px;
}
.ls-flow-arrow {
  font-size: 28px;
  color: var(--ink-faint);
  flex-shrink: 0;
}

/* —— 步骤列表 —— */
.ls-step-list {
  margin: 14px 0;
  padding-left: 0;
  counter-reset: step;
}
.ls-step-list li {
  counter-increment: step;
  font-size: 16px;
  color: var(--ink-soft);
  line-height: 1.8;
  padding: 8px 12px 8px 48px;
  position: relative;
  background: var(--paper);
  margin-bottom: 6px;
  border-radius: 8px;
  list-style: none;
}
.ls-step-list li::before {
  content: counter(step);
  position: absolute;
  left: 12px;
  top: 50%;
  transform: translateY(-50%);
  width: 26px;
  height: 26px;
  background: var(--cube-blue);
  color: var(--cube-white);
  border: 2px solid var(--ink);
  border-radius: 50%;
  text-align: center;
  line-height: 22px;
  font-weight: bold;
  font-size: 14px;
}

/* —— 公式盒子 —— */
.ls-formula-box {
  display: flex;
  flex-direction: column;
  gap: 10px;
  margin: 14px 0;
}
.ls-formula-item {
  display: flex;
  gap: 12px;
  align-items: center;
  padding: 12px 16px;
  background: var(--paper);
  border: 2.5px solid var(--ink);
  border-radius: 12px;
}
.formula-label {
  font-family: "Ma Shan Zheng", sans-serif;
  font-size: 22px;
  color: var(--cube-blue);
  flex-shrink: 0;
  min-width: 90px;
}
.formula-text {
  font-size: 16px;
  color: var(--ink-soft);
}
.ls-formula-single {
  display: flex;
  gap: 12px;
  align-items: center;
  padding: 14px 18px;
  background: var(--paper);
  border: 3px dashed var(--cube-blue);
  border-radius: 12px;
  margin: 12px 0;
}

/* —— 子步骤 —— */
.ls-sub-step {
  margin: 16px 0;
  padding: 14px 18px;
  background: var(--paper-light);
  border-left: 5px solid var(--cube-blue);
  border-radius: 8px;
}
.ls-sub-step h4 {
  font-family: "Ma Shan Zheng", sans-serif;
  font-size: 24px;
  color: var(--ink);
  margin-bottom: 8px;
}
.ls-sub-step p {
  font-size: 16px;
  color: var(--ink-soft);
  line-height: 1.7;
  margin: 4px 0;
}
.ls-case-list {
  list-style: none;
  padding: 0;
  margin: 8px 0;
}
.ls-case-list li {
  font-size: 15px;
  color: var(--ink-soft);
  padding: 8px 12px;
  margin-bottom: 6px;
  background: var(--paper);
  border-radius: 6px;
  border-left: 4px solid var(--cube-blue);
}

/* —— 课程主题色 —— */
.page-lesson-2 .ls-item.active {
  background: var(--cube-orange);
}
.page-lesson-2 .ls-section-tag {
  background: var(--cube-orange);
}
.page-lesson-2 .ls-nav-btn#ls2-next:not(:disabled) {
  background: var(--cube-orange);
  color: var(--cube-white);
}
.page-lesson-2 .ls-progress-fill {
  background: var(--cube-orange);
}
.page-lesson-3 .ls-item.active {
  background: var(--cube-blue);
}
.page-lesson-3 .ls-section-tag {
  background: var(--cube-blue);
}
.page-lesson-3 .ls-nav-btn#ls3-next:not(:disabled) {
  background: var(--cube-blue);
  color: var(--cube-white);
}
.page-lesson-3 .ls-progress-fill {
  background: var(--cube-blue);
}
.page-lesson-2 .ls-fun-fact {
  background: #ffe4c4;
}
.page-lesson-3 .ls-fun-fact {
  background: #cde4ff;
}

/* ============ AI 魔方语音推理台 ============ */
.lab-purple {
  background: #d8c3ef;
}
.ai-lab-page {
  max-width: 1180px;
}
.ai-lab-header {
  margin-bottom: 16px;
}
.ai-lab-kicker {
  display: inline-block;
  padding: 5px 12px;
  margin-bottom: 8px;
  background: #d8c3ef;
  border: 2px solid var(--ink);
  border-radius: 999px;
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 1.2px;
}
.ai-lab-note {
  max-width: 900px;
  padding: 13px 17px;
  margin: 0 auto 18px;
  border: 2px dashed var(--ink-soft);
  border-radius: 12px;
  background: rgba(255,255,255,0.55);
  color: var(--ink-soft);
  font-size: 15px;
}
.ai-lab-note b { color: var(--ink); }
.ai-lab-progress {
  max-width: 900px;
  padding: 14px 18px;
  margin: 0 auto 24px;
  background: var(--paper-light);
  border: 3px solid var(--ink);
  border-radius: 14px;
  box-shadow: 4px 4px 0 var(--ink-soft);
}
.ai-lab-progress > div:first-child {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  margin-bottom: 8px;
}
.ai-lab-progress b { font-size: 20px; }
.ai-lab-progress small { display: block; margin-top: 8px; color: var(--ink-soft); }
.ai-progress-track {
  height: 12px;
  overflow: hidden;
  border: 2px solid var(--ink);
  border-radius: 999px;
  background: #dedbd3;
}
.ai-progress-track i {
  display: block;
  width: 0;
  height: 100%;
  border-radius: inherit;
  background: var(--cube-green);
  transition: width .25s ease;
}
.ai-lab-layout {
  display: grid;
  grid-template-columns: minmax(300px, .95fr) minmax(410px, 1.05fr);
  gap: 26px;
  align-items: stretch;
}
.ai-cube-panel,
.ai-input-panel {
  background: var(--paper-light);
  border: 3.5px solid var(--ink);
  border-radius: 20px;
  box-shadow: 6px 7px 0 var(--ink-soft);
}
.ai-cube-panel { padding: 20px; }
.ai-input-panel { padding: 20px; }
.ai-cube-caption {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 12px;
  padding-bottom: 12px;
  border-bottom: 2px dashed var(--paper-edge);
}
.ai-cube-caption span { font-family: "Ma Shan Zheng", sans-serif; font-size: 27px; }
.ai-cube-caption small { color: var(--ink-soft); }
.voice-cube-scene {
  min-height: 390px;
  display: grid;
  place-items: center;
  overflow: hidden;
  perspective: 900px;
  touch-action: none;
  cursor: grab;
  user-select: none;
}
.voice-cube-scene:active { cursor: grabbing; }
.voice-cube {
  --cube-size: 180px;
  position: relative;
  width: var(--cube-size);
  height: var(--cube-size);
  transform-style: preserve-3d;
  transform: rotateX(var(--voice-x, -22deg)) rotateY(var(--voice-y, -34deg));
  transition: transform .28s ease-out;
}
.voice-cube.is-dragging { transition: none; }
.voice-face {
  position: absolute;
  inset: 0;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  grid-template-rows: repeat(3, 1fr);
  gap: 4px;
  padding: 4px;
  background: #242c35;
  border: 2px solid var(--ink);
  backface-visibility: visible;
}
.voice-face[data-face="F"] { transform: translateZ(calc(var(--cube-size) / 2)); }
.voice-face[data-face="B"] { transform: rotateY(180deg) translateZ(calc(var(--cube-size) / 2)); }
.voice-face[data-face="R"] { transform: rotateY(90deg) translateZ(calc(var(--cube-size) / 2)); }
.voice-face[data-face="L"] { transform: rotateY(-90deg) translateZ(calc(var(--cube-size) / 2)); }
.voice-face[data-face="U"] { transform: rotateX(90deg) translateZ(calc(var(--cube-size) / 2)); }
.voice-face[data-face="D"] { transform: rotateX(-90deg) translateZ(calc(var(--cube-size) / 2)); }
.voice-face.is-active { box-shadow: 0 0 0 5px rgba(247, 200, 75, .82); }
.voice-sticker {
  border-radius: 3px;
  background: #b7b8b4;
  box-shadow: inset 0 -2px 0 rgba(0,0,0,.13);
}
.voice-sticker.color-red,.entry-cell.color-red { background: var(--cube-red); }
.voice-sticker.color-orange,.entry-cell.color-orange { background: var(--cube-orange); }
.voice-sticker.color-yellow,.entry-cell.color-yellow { background: var(--cube-yellow); }
.voice-sticker.color-green,.entry-cell.color-green { background: var(--cube-green); }
.voice-sticker.color-blue,.entry-cell.color-blue { background: var(--cube-blue); }
.voice-sticker.color-white,.entry-cell.color-white { background: #f8f3e7; }
.ai-cube-legend {
  color: var(--ink-soft);
  font-size: 14px;
  text-align: center;
}
.ai-cube-legend i {
  display: inline-block;
  width: 13px;
  height: 13px;
  margin-right: 4px;
  vertical-align: -2px;
  background: #b7b8b4;
  border: 1px solid var(--ink-soft);
  border-radius: 2px;
}
.ai-face-tabs {
  display: grid;
  grid-template-columns: repeat(6, 1fr);
  gap: 7px;
  margin-bottom: 18px;
}
.ai-face-tab {
  min-height: 48px;
  border: 2px solid var(--ink);
  border-radius: 9px;
  background: #e5e0d4;
  color: var(--ink-soft);
  font: inherit;
  font-weight: 700;
  cursor: pointer;
}
.ai-face-tab:hover { transform: translateY(-2px); }
.ai-face-tab.is-current { background: var(--cube-yellow); color: var(--ink); box-shadow: 2px 3px 0 var(--ink-soft); }
.ai-face-tab.is-done { background: #b7dfc1; color: var(--ink); }
.ai-instruction-card {
  display: flex;
  align-items: center;
  gap: 13px;
  padding: 13px;
  margin-bottom: 17px;
  background: #eee6fa;
  border: 2px solid var(--ink);
  border-radius: 12px;
}
.ai-step-number {
  display: grid;
  place-items: center;
  flex: 0 0 auto;
  width: 40px;
  height: 40px;
  border: 2px solid var(--ink);
  border-radius: 50%;
  background: var(--cube-yellow);
  font-weight: 800;
}
.ai-instruction-card b { display: block; }
.ai-instruction-card p { margin: 3px 0 0; color: var(--ink-soft); font-size: 14px; }
.ai-entry-wrap { display: grid; grid-template-columns: 64px 1fr; gap: 8px; align-items: stretch; }
.ai-row-labels { display: grid; grid-template-rows: repeat(3, 1fr); gap: 7px; }
.ai-row-labels span { display: grid; place-items: center; color: var(--ink-soft); font-size: 12px; }
.ai-entry-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  grid-template-rows: repeat(3, 1fr);
  gap: 7px;
  padding: 7px;
  min-height: 245px;
  background: var(--ink);
  border: 3px solid var(--ink);
  border-radius: 12px;
}
.entry-cell {
  position: relative;
  border: 0;
  border-radius: 6px;
  background: #b7b8b4;
  color: rgba(30,37,48,.65);
  font: 700 16px/1 inherit;
  cursor: pointer;
  transition: transform .13s ease, box-shadow .13s ease;
}
.entry-cell:hover { transform: scale(.97); box-shadow: inset 0 0 0 3px rgba(255,255,255,.55); }
.entry-cell.is-center { cursor: not-allowed; }
.entry-cell.is-focus { box-shadow: inset 0 0 0 4px var(--cube-yellow); }
.entry-cell.is-just-filled { animation: faceletAppear .52s ease both; }
@keyframes faceletAppear {
  0% { transform: scale(.6); filter: brightness(1.55); }
  70% { transform: scale(1.06); }
  100% { transform: scale(1); filter: brightness(1); }
}
.entry-order {
  position: absolute;
  top: 50%;
  left: 50%;
  display: grid;
  place-items: center;
  width: 32px;
  height: 32px;
  transform: translate(-50%, -50%);
  border-radius: 50%;
  background: #ff4a42;
  color: #fff;
  font-size: 16px;
  line-height: 1;
  box-shadow: 1px 2px 0 rgba(74,53,32,.38);
  pointer-events: none;
}
.entry-cell.color-red .entry-order,
.entry-cell.color-green .entry-order,
.entry-cell.color-blue .entry-order { background: rgba(255,255,255,.9); color: var(--ink); }
.entry-center-label { position: absolute; right: 8px; bottom: 6px; color: rgba(30,37,48,.7); font-size: 13px; }
.ai-voice-card {
  margin-top: 17px;
  padding: 15px;
  background: #d9f0ee;
  border: 2px solid var(--ink);
  border-radius: 12px;
}
.ai-voice-title { display: flex; gap: 8px; align-items: center; }
.ai-voice-title span { font-size: 21px; }
.ai-voice-card p { min-height: 24px; margin: 7px 0 11px; color: var(--ink-soft); font-size: 14px; }
.ai-voice-actions { display: flex; gap: 10px; flex-wrap: wrap; }
.voice-button,.voice-confirm,.tool-button {
  border: 2.5px solid var(--ink);
  border-radius: 9px;
  padding: 9px 13px;
  color: var(--ink);
  font: inherit;
  font-weight: 700;
  cursor: pointer;
  box-shadow: 2px 3px 0 var(--ink-soft);
}
.voice-button { background: var(--cube-red); color: #fff; }
.voice-button.is-listening { background: var(--ink); animation: voicePulse .8s ease-in-out infinite alternate; }
.voice-confirm { background: var(--cube-yellow); }
.voice-confirm:disabled { opacity: .45; cursor: not-allowed; box-shadow: none; }
.ai-voice-card small { display: block; margin-top: 11px; color: var(--ink-soft); font-size: 12px; }
@keyframes voicePulse { to { transform: scale(1.03); } }
.ai-color-tools {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 7px;
  margin-top: 17px;
}
.ai-color-tools > span { margin-right: 3px; color: var(--ink-soft); font-size: 14px; }
.color-chip {
  width: 32px;
  height: 32px;
  border: 2px solid var(--ink);
  border-radius: 50%;
  color: var(--ink);
  font: 700 13px/1 inherit;
  cursor: pointer;
}
.color-chip.red { background: var(--cube-red); color: #fff; }
.color-chip.orange { background: var(--cube-orange); }
.color-chip.yellow { background: var(--cube-yellow); }
.color-chip.green { background: var(--cube-green); color: #fff; }
.color-chip.blue { background: var(--cube-blue); color: #fff; }
.color-chip.white { background: #f8f3e7; }
.color-chip.erase { width: auto; padding: 0 10px; border-radius: 16px; background: #d5d5d1; }
.color-chip.is-selected { outline: 4px solid #b59ae8; outline-offset: 2px; }
.ai-tools-row { display: flex; gap: 10px; margin-top: 18px; }
.tool-button { background: var(--paper); }
.tool-button.danger { color: #a82629; }
.ai-lab-footer-actions { display: flex; gap: 10px; margin-top: 18px; }
.ai-lab-footer-actions button {
  padding: 8px 12px;
  border: 2px solid var(--ink);
  border-radius: 8px;
  background: var(--paper);
  color: var(--ink);
  font: inherit;
  font-weight: 700;
  cursor: pointer;
}
.ai-lab-footer-actions button:disabled { opacity: .45; cursor: not-allowed; }
.ai-lab-footer-actions #voice-reset-btn { color: #a82629; }
.ai-phase-two { margin-top: 13px; color: var(--ink-soft); font-size: 13px; }

/* ============ 图片识别复原台 ============ */
.photo-solve-page { max-width: 1180px; }
.photo-header { margin-bottom: 14px; }
.photo-kicker {
  display: inline-block;
  padding: 5px 12px;
  margin-bottom: 8px;
  background: #aee0cf;
  border: 2px solid var(--ink);
  border-radius: 999px;
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 1.2px;
}
.photo-privacy-note,
.photo-progress,
.photo-solve-ready,
.photo-solution {
  max-width: 980px;
  margin-left: auto;
  margin-right: auto;
  border: 3px solid var(--ink);
  border-radius: 16px;
  background: var(--paper-light);
  box-shadow: 5px 6px 0 var(--ink-soft);
}
.photo-privacy-note {
  padding: 12px 16px;
  margin-bottom: 16px;
  border-style: dashed;
  box-shadow: none;
  color: var(--ink-soft);
  font-size: 15px;
}
.photo-privacy-note b { color: var(--ink); }
.photo-progress { padding: 14px 18px; margin-bottom: 22px; }
.photo-progress > div:first-child { display: flex; justify-content: space-between; margin-bottom: 8px; }
.photo-progress b { font-size: 20px; }
.photo-progress small { display: block; margin-top: 8px; color: var(--ink-soft); }
.photo-progress-track { height: 12px; overflow: hidden; background: #dedbd3; border: 2px solid var(--ink); border-radius: 999px; }
.photo-progress-track i { display: block; width: 0; height: 100%; background: var(--cube-green); border-radius: inherit; transition: width .25s ease; }
.photo-layout { display: grid; grid-template-columns: 1.05fr .95fr; gap: 26px; align-items: stretch; }
.photo-capture-panel,
.photo-check-panel {
  padding: 20px;
  border: 3.5px solid var(--ink);
  border-radius: 20px;
  background: var(--paper-light);
  box-shadow: 6px 7px 0 var(--ink-soft);
}
.photo-face-tabs { display: grid; grid-template-columns: repeat(6, 1fr); gap: 7px; margin-bottom: 15px; }
.photo-face-tab {
  min-height: 45px;
  border: 2px solid var(--ink);
  border-radius: 9px;
  color: var(--ink);
  background: var(--paper);
  font: inherit;
  font-weight: 700;
  cursor: pointer;
}
.photo-face-tab.is-current { background: var(--cube-yellow); transform: translateY(-2px); box-shadow: 2px 3px 0 var(--ink-soft); }
.photo-face-tab.is-done::after { content: " ✓"; color: #20754e; }
.photo-instruction { min-height: 65px; padding: 12px 14px; margin-bottom: 14px; border-left: 5px solid var(--cube-green); border-radius: 8px; background: #e4f2ec; color: var(--ink-soft); font-size: 15px; line-height: 1.65; }
.photo-instruction b { display: block; color: var(--ink); font-size: 17px; }
.photo-camera-actions { display: grid; grid-template-columns: 1fr 1fr; gap: 11px; }
.photo-open-camera {
  min-height: 116px;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 8px;
  border: 3px solid var(--ink);
  border-radius: 14px;
  background: var(--cube-yellow);
  color: var(--ink);
  font: inherit;
  font-weight: 700;
  cursor: pointer;
  box-shadow: 3px 4px 0 var(--ink-soft);
}
.photo-open-camera:hover { transform: translateY(-2px); box-shadow: 4px 6px 0 var(--ink-soft); }
.photo-open-camera span { display: grid; place-items: center; width: 35px; height: 35px; border: 2px solid var(--ink); border-radius: 50%; background: #fff8e7; color: var(--cube-red); font-size: 24px; line-height: 1; }
.photo-upload {
  min-height: 116px;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 5px;
  border: 3px dashed var(--ink);
  border-radius: 14px;
  background: #fff9e7;
  color: var(--ink);
  cursor: pointer;
  text-align: center;
}
.photo-upload:hover { background: #fff0b7; }
.photo-upload input { position: absolute; width: 1px; height: 1px; opacity: 0; pointer-events: none; }
.photo-upload-icon { width: 33px; height: 33px; display: grid; place-items: center; border: 2px solid var(--ink); border-radius: 7px; font-size: 21px; background: var(--cube-yellow); }
.photo-upload small, .photo-capture-tip { color: var(--ink-soft); font-size: 13px; }
.photo-guide-controls { margin: 14px 0 3px; padding: 10px 12px; border: 2px dashed var(--ink-soft); border-radius: 10px; background: #f7f1df; }
.photo-guide-controls label { display: flex; align-items: center; justify-content: space-between; color: var(--ink); font-size: 14px; font-weight: 700; }
.photo-guide-controls label b { color: #24724f; }
.photo-guide-controls input { width: 100%; accent-color: var(--cube-green); cursor: pointer; }
.photo-guide-controls small { display: block; color: var(--ink-soft); font-size: 12px; line-height: 1.45; }
.photo-camera-wrap { position: relative; aspect-ratio: 1; max-width: 350px; margin: 15px auto 0; overflow: hidden; border: 3px solid var(--ink); border-radius: 12px; background: #242322; }
.photo-camera-wrap video { display: block; width: 100%; height: 100%; object-fit: cover; transform: scaleX(-1); }
.photo-camera-wrap .photo-guide-grid { z-index: 1; }
.photo-live-scan-guide { position: absolute; z-index: 2; top: 10px; left: 10px; right: 10px; padding: 9px 11px 8px 49px; border: 2px solid var(--ink); border-radius: 10px; background: rgba(255,249,231,.94); box-shadow: 2px 3px 0 rgba(39,29,19,.65); color: var(--ink); pointer-events: none; }
.photo-live-scan-guide::before { content: "↻"; position: absolute; left: 11px; top: 50%; transform: translateY(-50%); width: 27px; height: 27px; display: grid; place-items: center; border-radius: 50%; background: var(--cube-yellow); border: 2px solid var(--ink); font-size: 20px; line-height: 1; }
.photo-live-scan-guide span { display: block; color: #237354; font-size: 11px; font-weight: 700; letter-spacing: .6px; }.photo-live-scan-guide b { display: block; font-size: 14px; line-height: 1.3; }.photo-live-scan-guide p { margin: 2px 0 0; color: var(--ink-soft); font-size: 11px; line-height: 1.35; }
.photo-live-scan-diagram { display: flex; align-items: center; gap: 5px; margin-top: 5px; }.photo-live-scan-diagram i { width: 22px; height: 22px; display: grid; place-items: center; border: 1.5px solid var(--ink); border-radius: 4px; font-size: 11px; font-style: normal; font-weight: 700; }.photo-live-scan-diagram strong { font-size: 17px; line-height: 1; }.photo-live-scan-diagram .color-red { background: var(--cube-red); color: #fff; }.photo-live-scan-diagram .color-orange { background: var(--cube-orange); }.photo-live-scan-diagram .color-yellow { background: var(--cube-yellow); }.photo-live-scan-diagram .color-green { background: var(--cube-green); color: #fff; }.photo-live-scan-diagram .color-blue { background: var(--cube-blue); color: #fff; }.photo-live-scan-diagram .color-white { background: #f8f3e7; }
.photo-camera-toolbar { position: absolute; z-index: 2; bottom: 12px; left: 12px; right: 12px; display: flex; justify-content: space-between; gap: 10px; }
.photo-camera-toolbar .photo-primary, .photo-camera-toolbar .photo-secondary { padding: 8px 11px; }
.photo-preview-wrap { position: relative; aspect-ratio: 1; max-width: 350px; margin: 15px auto 0; overflow: hidden; border: 3px solid var(--ink); border-radius: 12px; background: #c9c9c5; }
.photo-preview-wrap img { width: 100%; height: 100%; object-fit: cover; display: block; }
.photo-guide-grid { --photo-guide-size: 48%; position: absolute; width: var(--photo-guide-size); height: var(--photo-guide-size); left: 50%; top: 50%; transform: translate(-50%, -50%); display: grid; grid-template-columns: repeat(3, 1fr); grid-template-rows: repeat(3, 1fr); pointer-events: none; }
.photo-guide-grid i { border: 2px solid rgba(255,255,255,.9); background: rgba(24,36,54,.10); box-shadow: inset 0 0 0 1px rgba(24,36,54,.28); }
.photo-capture-tip { margin: 11px 0 0; line-height: 1.6; }
.photo-calibration-status { margin: 8px 0 0; padding: 8px 10px; border-radius: 8px; background: #e4f2ec; color: #2d6f54; font-size: 13px; line-height: 1.55; }
.photo-check-title { display: flex; align-items: baseline; justify-content: space-between; gap: 10px; margin-bottom: 13px; }
.photo-check-title b { font-size: 19px; }
.photo-check-title small { color: var(--ink-soft); font-size: 12px; }
.photo-entry-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 8px; max-width: 360px; margin: 0 auto 17px; padding: 10px; background: #4b3925; border-radius: 13px; }
.photo-cell { position: relative; aspect-ratio: 1; border: 3px solid rgba(255,255,255,.72); border-radius: 7px; background: #b8b8b5; cursor: pointer; box-shadow: inset 0 -4px 0 rgba(0,0,0,.08); }
.photo-cell.is-center { cursor: not-allowed; border-color: var(--ink); }
.photo-cell::after { content: attr(data-order); position: absolute; right: 5px; top: 3px; width: 19px; height: 19px; display: grid; place-items: center; border-radius: 50%; color: #fff; background: rgba(20,28,39,.55); font-size: 11px; font-weight: 700; }
.photo-cell.color-red { background: var(--cube-red); }.photo-cell.color-orange { background: var(--cube-orange); }.photo-cell.color-yellow { background: var(--cube-yellow); }.photo-cell.color-green { background: var(--cube-green); }.photo-cell.color-blue { background: var(--cube-blue); }.photo-cell.color-white { background: #f8f3e7; }
.photo-color-tools { display: flex; flex-wrap: wrap; align-items: center; gap: 8px; }
.photo-color-tools > span { color: var(--ink-soft); font-size: 14px; font-weight: 700; }
.photo-color-chip { width: 34px; height: 34px; border: 2px solid var(--ink); border-radius: 50%; font: inherit; font-size: 13px; font-weight: 700; color: var(--ink); cursor: pointer; }
.photo-color-chip.red { background: var(--cube-red); color: #fff; }.photo-color-chip.orange { background: var(--cube-orange); }.photo-color-chip.yellow { background: var(--cube-yellow); }.photo-color-chip.green { background: var(--cube-green); color: #fff; }.photo-color-chip.blue { background: var(--cube-blue); color: #fff; }.photo-color-chip.white { background: #f8f3e7; }
.photo-color-chip.is-selected { outline: 4px solid #b59ae8; outline-offset: 2px; }
.photo-check-message { min-height: 42px; margin: 14px 0; color: var(--ink-soft); font-size: 14px; line-height: 1.55; }
.photo-actions, .photo-solution-actions { display: flex; justify-content: space-between; gap: 12px; }
.photo-primary, .photo-secondary { border: 2.5px solid var(--ink); border-radius: 10px; padding: 10px 15px; font: inherit; font-weight: 700; cursor: pointer; box-shadow: 2px 3px 0 var(--ink-soft); }
.photo-primary { color: var(--ink); background: var(--cube-yellow); }.photo-primary:hover { background: #ffdf70; }.photo-primary:disabled { cursor: not-allowed; opacity: .5; box-shadow: none; }.photo-secondary { background: var(--paper); color: var(--ink); }.photo-secondary:hover { background: #efe7d5; }
.photo-solve-ready { display: flex; align-items: center; justify-content: space-between; gap: 20px; padding: 20px; margin-top: 28px; background: #e4f2ec; }
.photo-solve-ready span, .photo-solution-head span { color: #237354; font-size: 13px; font-weight: 700; letter-spacing: 1px; }.photo-solve-ready h3, .photo-solution-head h3 { margin: 4px 0; font-family: "Ma Shan Zheng", sans-serif; font-size: 30px; }.photo-solve-ready p { margin: 0; color: var(--ink-soft); font-size: 14px; }.photo-solve-button { flex-shrink: 0; }
.photo-solution { padding: 22px; margin-top: 28px; }.photo-solution-head { display: flex; align-items: flex-start; justify-content: space-between; gap: 18px; }.photo-solution-head p { margin: 0; color: var(--ink-soft); }.photo-solution-tools { display: flex; flex-wrap: wrap; justify-content: flex-end; gap: 9px; }.photo-hold-guide { display: flex; align-items: center; gap: 14px; padding: 12px 14px; margin: 17px 0 4px; border: 2px dashed var(--ink-soft); border-radius: 12px; background: #e9f3f8; }.photo-hold-guide > div:first-child { min-width: 156px; }.photo-hold-guide span { color: #237354; font-size: 12px; font-weight: 700; letter-spacing: .5px; }.photo-hold-guide h4 { margin: 2px 0 0; color: var(--ink); font-size: 20px; }.photo-hold-guide p { flex: 1; margin: 0; color: var(--ink-soft); font-size: 13px; line-height: 1.6; }.photo-hold-guide p b { color: var(--ink); }.photo-hold-guide p strong { color: var(--cube-red); }.photo-hold-cube { position: relative; width: 88px; height: 58px; flex: 0 0 88px; }.photo-hold-cube i { position: absolute; display: grid; place-items: center; width: 35px; height: 35px; border: 2px solid var(--ink); color: var(--ink); font-size: 13px; font-style: normal; font-weight: 700; line-height: 1; }.photo-hold-cube small { font-size: 10px; }.hold-u { left: 26px; top: 0; transform: skewX(-28deg) scaleY(.68); background: #f8f3e7; }.hold-f { left: 10px; top: 27px; transform: skewY(30deg); background: var(--cube-green); color: #fff !important; }.hold-r { left: 45px; top: 27px; transform: skewY(-30deg); background: var(--cube-red); color: #fff !important; }.photo-solution-body { display: grid; grid-template-columns: 1fr .95fr; gap: 20px; align-items: center; margin: 18px 0; }.photo-cube-stage { overflow: hidden; border: 3px solid var(--ink); border-radius: 13px; background: #f7f1df; }.photo-solution-body twisty-player { display: block; width: 100%; height: 290px; background: #f7f1df; }.photo-cube-stage p { margin: 0; padding: 8px 12px; border-top: 2px dashed var(--ink-soft); color: #237354; background: #e4f2ec; font-size: 13px; font-weight: 700; text-align: center; }.photo-next-move { padding: 26px 18px; text-align: center; border: 3px dashed var(--ink); border-radius: 15px; background: #fff9e7; }.photo-next-move span { color: var(--ink-soft); font-size: 14px; }.photo-next-move b { display: block; margin: 4px 0; color: var(--cube-red); font-size: 50px; line-height: 1; }.photo-next-move p { margin: 8px 0; color: var(--ink); font-size: 17px; font-weight: 700; }.photo-next-move small { color: var(--ink-soft); }.photo-alg-details { margin-top: 18px; color: var(--ink-soft); }.photo-alg-details summary { cursor: pointer; font-weight: 700; }.photo-alg-details p { word-break: break-word; line-height: 1.7; }


/* ============ 响应式 ============ */
@media (max-width: 860px) {
  .hero {
    grid-template-columns: 1fr;
  }
  .hero-title {
    font-size: 38px;
  }
  .card-grid {
    grid-template-columns: 1fr;
  }
  .lab-main {
    grid-row: auto;
  }
  .lab-content {
    grid-template-columns: 1fr;
  }
  .lab-cube twisty-player {
    width: 180px;
    height: 220px;
  }
  .ai-lab-layout {
    grid-template-columns: 1fr;
  }
  .photo-layout,
  .photo-solution-body { grid-template-columns: 1fr; }
  .nav-links {
    display: none;
  }
  .top-nav {
    flex-wrap: wrap;
    gap: 12px;
  }
}

@media (max-width: 760px) {
  .ai-lab-page { padding-left: 16px; padding-right: 16px; }
  .ai-face-tabs { gap: 5px; }
  .ai-face-tab { min-height: 43px; font-size: 12px; }
  .voice-cube-scene { min-height: 315px; }
  .voice-cube { --cube-size: 150px; }
  .ai-entry-grid { min-height: 220px; }
  .photo-face-tabs { grid-template-columns: repeat(3, 1fr); }
  .photo-camera-actions { grid-template-columns: 1fr; }
  .photo-solve-ready,
  .photo-solution-head { align-items: stretch; flex-direction: column; }
  .ai-cube-caption { align-items: flex-start; flex-direction: column; gap: 2px; }
  .page-title { font-size: 38px; }
  .lessons { grid-template-columns: 1fr; }

  /* 课程详情页响应式 */
  .lesson-layout {
    grid-template-columns: 1fr;
  }
  .lesson-sidebar {
    position: static;
    transform: none;
  }
  .ls-section-body {
    grid-template-columns: 1fr;
  }
  .ls-cube-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .ls-cube-grid-item twisty-player {
    max-width: 140px;
    height: 160px;
  }
  .lesson-content {
    padding: 22px 20px;
  }
  .ls-section-title {
    font-size: 28px;
  }
}