/* ============ 基础 ============ */
:root {
  --bg: #f6f5fb;
  --panel: #ffffff;
  --ink: #1f2330;
  --muted: #6b7280;
  --line: #e6e4ef;
  --brand: #7c5cd6;
  --brand-2: #f5b84b;
  --soft: #efeafb;
  --ok: #16a34a;
  --shadow: 0 6px 20px rgba(60, 40, 120, 0.08);
  --radius: 14px;
}
html[data-theme="dark"] {
  --bg: #151327;
  --panel: #1e1b33;
  --ink: #e9e6f5;
  --muted: #a09ab8;
  --line: #2e2a4a;
  --brand: #a78bfa;
  --brand-2: #fbbf24;
  --soft: #2a2447;
  --ok: #4ade80;
  --shadow: 0 6px 20px rgba(0, 0, 0, 0.38);
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: "Segoe UI", "Microsoft YaHei", "PingFang SC", system-ui, sans-serif;
  background: var(--bg);
  color: var(--ink);
  line-height: 1.75;
  font-size: 15px;
}
a { color: var(--brand); text-decoration: none; }
a:hover { text-decoration: underline; }

/* ============ 顶栏 ============ */
.topbar {
  position: sticky; top: 0; z-index: 50;
  display: flex; align-items: center; gap: 10px;
  padding: 10px 18px;
  background: color-mix(in srgb, var(--bg) 82%, transparent);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--line);
}
.brand { font-weight: 800; font-size: 17px; white-space: nowrap; color: var(--ink); }
.brand:hover { text-decoration: none; }
.search-box { position: relative; flex: 1; max-width: 560px; margin: 0 auto; }
.search-box input {
  width: 100%; padding: 9px 16px;
  border: 1px solid var(--line); border-radius: 999px;
  background: var(--panel); color: var(--ink); font-size: 14px; outline: none;
}
.search-box input:focus { border-color: var(--brand); }
.search-results {
  position: absolute; top: calc(100% + 6px); left: 0; right: 0;
  background: var(--panel); border: 1px solid var(--line); border-radius: 14px;
  box-shadow: var(--shadow); max-height: 380px; overflow: auto;
  display: none; z-index: 60;
}
.search-results.open { display: block; }
.sr-item { padding: 10px 14px; border-bottom: 1px solid var(--line); cursor: pointer; }
.sr-item:last-child { border-bottom: none; }
.sr-item:hover { background: var(--soft); }
.sr-item .t { font-weight: 700; font-size: 14px; }
.sr-item .p { font-size: 12px; color: var(--muted); margin-top: 2px; }
.sr-item mark { background: #fde68a; color: #111; border-radius: 3px; padding: 0 2px; }
.sr-head {
  font-size: 12px; font-weight: 800; color: var(--brand);
  padding: 8px 14px 4px; letter-spacing: 0.5px;
}

.pill-btn {
  border: 1px solid var(--line); background: var(--panel); color: var(--ink);
  padding: 8px 14px; border-radius: 999px; cursor: pointer; font-size: 13px;
  white-space: nowrap;
}
.pill-btn:hover { border-color: var(--brand); color: var(--brand); }
.pill-btn.on { background: var(--brand); border-color: var(--brand); color: #fff; }
.icon-btn {
  border: 1px solid var(--line); background: var(--panel); color: var(--ink);
  width: 38px; height: 38px; border-radius: 10px; cursor: pointer; font-size: 16px;
  flex: 0 0 auto;
}

/* ============ 侧边栏 ============ */
.app { display: flex; min-height: calc(100vh - 59px); }
.sidebar {
  width: 248px; flex: 0 0 248px;
  border-right: 1px solid var(--line);
  background: var(--panel);
  padding: 18px 12px;
  display: flex; flex-direction: column;
  position: sticky; top: 59px; height: calc(100vh - 59px); overflow-y: auto;
}
.side-head { font-size: 12px; font-weight: 800; color: var(--muted); letter-spacing: 1px; padding: 0 8px 8px; }
.sidebar nav { display: flex; flex-direction: column; gap: 2px; }
.sidebar nav a {
  padding: 7px 10px; border-radius: 8px; font-size: 13.5px; color: var(--ink);
}
.sidebar nav a:hover { background: var(--soft); text-decoration: none; }
.sidebar nav a.active { background: var(--soft); color: var(--brand); font-weight: 700; }
.side-foot { margin-top: auto; padding-top: 16px; font-size: 11px; color: var(--muted); text-align: center; }

/* ============ 主区 ============ */
.main { flex: 1; min-width: 0; padding: 26px 30px 40px; max-width: 1000px; }
.doc-head .crumbs { font-size: 12.5px; color: var(--muted); }
.doc-head h1 { font-size: 26px; margin: 8px 0 14px; }

.markdown-body {
  background: var(--panel); border: 1px solid var(--line);
  border-radius: var(--radius); padding: 26px 30px; box-shadow: var(--shadow);
}
.markdown-body h1 {
  font-size: 22px; border-bottom: 2px solid var(--brand);
  padding-bottom: 8px; margin: 6px 0 18px; color: var(--brand);
}
.markdown-body h2 {
  font-size: 18px; margin: 26px 0 10px; color: var(--brand);
  border-left: 4px solid var(--brand); padding-left: 10px;
}
.markdown-body h3 { font-size: 15.5px; margin: 20px 0 8px; }
.markdown-body p { margin: 10px 0; }
.markdown-body ul, .markdown-body ol { margin: 8px 0; padding-left: 24px; }
.markdown-body li { margin: 5px 0; }
.markdown-body table {
  border-collapse: collapse; width: 100%; margin: 14px 0; font-size: 13.5px;
  display: block; overflow-x: auto;
}
.markdown-body th, .markdown-body td {
  border: 1px solid var(--line); padding: 7px 10px; text-align: left; vertical-align: top;
}
.markdown-body th { background: var(--soft); font-weight: 700; }
.markdown-body blockquote {
  border-left: 4px solid var(--brand-2); background: var(--soft);
  margin: 12px 0; padding: 8px 14px; border-radius: 0 10px 10px 0;
}
.markdown-body code {
  background: var(--soft); padding: 2px 6px; border-radius: 6px;
  font-family: Consolas, "Courier New", monospace; font-size: 13px;
}
.markdown-body hr { border: none; border-top: 2px dashed var(--line); margin: 20px 0; }
.markdown-body img { max-width: 100%; border-radius: 10px; }

/* 歌词板 */
.lyric {
  background: var(--soft); border-radius: 12px; padding: 14px 18px;
  font-family: Consolas, "Courier New", monospace; font-size: 13.5px;
  line-height: 2; white-space: pre-wrap; margin: 12px 0;
}
/* 对 / 错 标记 */
.ok-mark { color: var(--ok); font-weight: 800; }
.no-mark { color: #e5484d; font-weight: 800; }
.hl { background: var(--brand-2); color: #1f2330; border-radius: 4px; padding: 0 4px; font-weight: 700; }
.hl-b { color: var(--brand); font-weight: 800; }
/* 音标、短代码：窄列里也不许断行 */
.nowrap { white-space: nowrap; }

/* ============ 知识点折叠卡（每节课点开看全部） ============ */
.kp-toolbar {
  display: flex; align-items: center; gap: 10px; flex-wrap: wrap;
  margin: 16px 0 12px;
}
.kp-count { font-size: 12.5px; color: var(--muted); margin-left: auto; }

.kp-grid {
  display: grid; grid-template-columns: repeat(auto-fill, minmax(215px, 1fr));
  gap: 8px; margin: 14px 0 6px;
}
.kp-chip {
  display: flex; align-items: center; gap: 8px;
  border: 1px solid var(--line); background: var(--panel); color: var(--ink);
  border-radius: 10px; padding: 8px 12px; font-size: 13px;
}
.kp-chip:hover { border-color: var(--brand); color: var(--brand); text-decoration: none; }
.kp-chip i {
  font-style: normal; font-weight: 800; font-size: 11.5px;
  background: var(--soft); color: var(--brand);
  border-radius: 999px; padding: 1px 8px; flex: 0 0 auto;
}

details.kp {
  border: 1px solid var(--line); border-radius: 12px;
  background: var(--panel); margin: 10px 0; overflow: hidden;
}
details.kp[open] { border-color: color-mix(in srgb, var(--brand) 45%, var(--line)); }
details.kp > summary {
  cursor: pointer; padding: 12px 16px; font-weight: 700; font-size: 15px;
  display: flex; align-items: center; gap: 10px;
  list-style: none; user-select: none;
  background: var(--soft);
}
details.kp > summary::-webkit-details-marker { display: none; }
details.kp > summary::after {
  content: "▸"; margin-left: auto; color: var(--brand); font-size: 14px;
  transition: transform 0.15s ease;
}
details.kp[open] > summary::after { transform: rotate(90deg); }
details.kp > summary:hover { color: var(--brand); }
details.kp .kp-n {
  flex: 0 0 auto; font-size: 11.5px; font-weight: 800;
  background: var(--brand); color: #fff;
  border-radius: 999px; padding: 2px 9px;
}
.kp-body { padding: 4px 18px 16px; }
.kp-body > :first-child { margin-top: 10px; }
.kp-body > :last-child { margin-bottom: 4px; }

/* 高亮定位（从知识点总览跳过来时闪一下） */
details.kp.flash { animation: kpflash 1.4s ease; }
@keyframes kpflash {
  0%   { box-shadow: 0 0 0 3px color-mix(in srgb, var(--brand) 55%, transparent); }
  100% { box-shadow: 0 0 0 3px transparent; }
}

.doc-nav { display: flex; gap: 12px; margin-top: 26px; }
.doc-nav a {
  flex: 1; padding: 12px 16px; border: 1px solid var(--line); border-radius: 12px;
  background: var(--panel); color: var(--ink); font-size: 13.5px;
}
.doc-nav a:hover { border-color: var(--brand); text-decoration: none; }
.doc-nav .next { text-align: right; }
.doc-nav small { display: block; color: var(--muted); font-size: 11.5px; }

/* ============ 首页 ============ */
.hero { text-align: center; padding: 26px 10px 6px; }
.hero-badge {
  display: inline-block; font-size: 12px; font-weight: 800; letter-spacing: 2px;
  color: var(--brand); background: var(--soft); padding: 5px 14px; border-radius: 999px;
}
.hero h1 { font-size: 30px; margin: 14px 0 6px; }
.hero .sub { color: var(--muted); font-size: 15px; }
.stats { display: flex; justify-content: center; gap: 34px; margin: 22px 0 6px; flex-wrap: wrap; }
.stat b { display: block; font-size: 28px; color: var(--brand); }
.stat span { font-size: 12.5px; color: var(--muted); }

.cards {
  display: grid; grid-template-columns: repeat(auto-fill, minmax(210px, 1fr));
  gap: 14px; margin: 22px 0;
}
.card {
  background: var(--panel); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 18px; box-shadow: var(--shadow); transition: transform 0.15s ease;
}
.card:hover { transform: translateY(-3px); text-decoration: none; }
.card .em { font-size: 28px; }
.card b { display: block; margin: 8px 0 4px; font-size: 15.5px; color: var(--ink); }
.card span { font-size: 12.5px; color: var(--muted); }

.section { margin: 30px 0; }
.section h2 { font-size: 20px; margin: 0 0 4px; }
.section .desc { color: var(--muted); font-size: 13.5px; margin: 4px 0 14px; }

.chips { display: flex; flex-wrap: wrap; gap: 8px; margin-bottom: 16px; }
.chip {
  border: 1px solid var(--line); background: var(--panel); color: var(--ink);
  padding: 6px 14px; border-radius: 999px; font-size: 13px; cursor: pointer;
}
.chip.on { background: var(--brand); border-color: var(--brand); color: #fff; }

.lesson-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(250px, 1fr)); gap: 10px; }
.lesson {
  background: var(--panel); border: 1px solid var(--line); border-radius: 12px;
  padding: 11px 14px; cursor: pointer; transition: transform 0.12s ease;
}
.lesson:hover { transform: translateY(-2px); border-color: var(--brand); text-decoration: none; }
.lesson .num { color: var(--brand); font-weight: 800; font-size: 13px; margin-right: 7px; }
.lesson .t { color: var(--ink); font-size: 13.5px; }
.lesson .cat {
  display: inline-block; margin-left: 8px; font-size: 11px; color: var(--muted);
  background: var(--soft); padding: 1px 8px; border-radius: 999px;
}
.lesson .kp-tag { background: color-mix(in srgb, var(--brand) 14%, var(--panel)); color: var(--brand); font-weight: 700; }
.lesson.done { border-color: var(--ok); background: color-mix(in srgb, var(--ok) 6%, var(--panel)); }
.lesson.done .num::after { content: " ✓"; color: var(--ok); }

/* ============ 弹窗 ============ */
.overlay {
  position: fixed; inset: 0; background: rgba(10, 14, 30, 0.5);
  z-index: 90; display: none;
}
.overlay.open { display: block; }
.modal {
  position: fixed; top: 50%; left: 50%; transform: translate(-50%, -50%);
  width: min(540px, 92vw); max-height: 84vh; overflow: auto;
  background: var(--panel); border-radius: 18px; box-shadow: var(--shadow);
  padding: 24px; z-index: 100; display: none;
}
.modal.open { display: block; }
.modal h3 { margin: 0 0 12px; }
.q-type {
  display: inline-block; font-size: 11.5px; font-weight: 800;
  background: var(--soft); color: var(--brand); padding: 3px 12px; border-radius: 999px;
}
.q-text { font-size: 17px; margin: 12px 0 6px; font-weight: 600; }
.q-src { font-size: 12px; color: var(--muted); }
.timer-row { display: flex; align-items: center; gap: 10px; margin: 16px 0; flex-wrap: wrap; }
.tval { font-size: 22px; font-weight: 800; color: var(--brand); min-width: 90px; }
.timer-row select { padding: 8px 10px; border-radius: 10px; border: 1px solid var(--line); background: var(--panel); color: var(--ink); }
.modal-actions { display: flex; gap: 10px; justify-content: flex-end; }

/* ============ 其他 ============ */
.to-top {
  position: fixed; right: 22px; bottom: 24px; z-index: 80;
  width: 42px; height: 42px; border-radius: 50%;
  border: 1px solid var(--line); background: var(--panel); color: var(--brand);
  font-size: 18px; cursor: pointer; box-shadow: var(--shadow);
  display: none;
}
.to-top.show { display: block; }
.foot { text-align: center; color: var(--muted); font-size: 12.5px; padding: 20px 0 4px; }

/* ============ 响应式：平板 / 手机 ============ */
@media (max-width: 860px) {
  .sidebar {
    position: fixed; top: 0; left: 0; z-index: 80;
    height: 100vh; transform: translateX(-100%); transition: transform 0.25s ease;
    box-shadow: var(--shadow);
  }
  .sidebar.open { transform: translateX(0); }
  .main { padding: 16px 14px 32px; }
  .lesson-grid { grid-template-columns: 1fr; }
  .kp-grid { grid-template-columns: 1fr; }
  .brand { display: none; }
  .search-box { max-width: none; }
  /* iOS 上 <16px 的输入框被聚焦时会自动放大整页 */
  .search-box input { font-size: 16px; padding: 8px 14px; }
  .topbar { padding: 8px 12px; gap: 8px; }
  .pill-btn { padding: 7px 12px; font-size: 12.5px; }
  .icon-btn { width: 36px; height: 36px; }
}

/* ============ 响应式：手机 ============ */
@media (max-width: 600px) {
  body { font-size: 14.5px; line-height: 1.7; }

  /* 正文卡片：桌面 26/30 的内边距在手机上太浪费 */
  .markdown-body { padding: 16px 14px; border-radius: 12px; }
  .markdown-body h1 { font-size: 19px; margin: 2px 0 14px; padding-bottom: 6px; }
  .markdown-body h2 { font-size: 16.5px; margin: 20px 0 8px; padding-left: 8px; }
  .markdown-body h3 { font-size: 15px; }
  .markdown-body p { margin: 8px 0; }
  .markdown-body ul, .markdown-body ol { padding-left: 20px; }

  /* 表格：手机上缩字号，横向可滑 */
  .markdown-body table { font-size: 12.5px; margin: 10px 0; }
  .markdown-body th, .markdown-body td { padding: 6px 8px; }

  /* 歌词块：桌面行高 2 在手机上会撑掉大半屏 */
  .lyric { line-height: 1.7; font-size: 12.5px; padding: 12px 13px; border-radius: 10px; }

  /* 页头 */
  .doc-head h1 { font-size: 19px; margin: 6px 0 12px; line-height: 1.4; }
  .doc-head .crumbs { font-size: 12px; }
  .hero { padding: 16px 6px 4px; }
  .hero h1 { font-size: 23px; }
  .hero .sub { font-size: 13.5px; }
  .stats { gap: 22px; }
  .stat b { font-size: 23px; }

  /* 知识点折叠卡 */
  details.kp > summary { padding: 11px 12px; font-size: 14px; gap: 8px; }
  .kp-body { padding: 2px 13px 14px; }
  .kp-grid { gap: 6px; }
  .kp-chip { padding: 9px 11px; font-size: 13px; }
  .kp-toolbar { gap: 8px; }
  .kp-count { width: 100%; margin-left: 0; text-align: right; }

  /* 上一课 / 下一课：手机上竖排，别挤成两半 */
  .doc-nav { flex-direction: column; gap: 8px; }
  .doc-nav .next { text-align: left; }

  /* 首页 */
  .cards { grid-template-columns: 1fr 1fr; gap: 10px; }
  .card { padding: 14px; }
  .card .em { font-size: 24px; }

  .modal { padding: 18px; width: 94vw; }
  .q-text { font-size: 16px; }
  .to-top { right: 14px; bottom: 16px; width: 40px; height: 40px; }

  /* 刘海屏 / 横屏安全区 */
  .topbar {
    padding-left: max(12px, env(safe-area-inset-left));
    padding-right: max(12px, env(safe-area-inset-right));
  }
  .main { padding-bottom: max(32px, env(safe-area-inset-bottom)); }
  .to-top { right: max(14px, env(safe-area-inset-right)); }
}