/* CS 329Z 中文学习站 */
:root {
  --cardinal: #8c1515;
  --cardinal-dark: #6b1010;
  --cardinal-ink: #2e0d0d;
  --ink: #232326;
  --ink-soft: #5d5d66;
  --paper: #fdfcfb;
  --card: #ffffff;
  --line: #e8e4e0;
  --line-soft: #f0ece8;
  --amber: #b45309;
  --amber-bg: #fef3c7;
  --gray: #6b7280;
  --gray-bg: #f3f4f6;
  --must-bg: #fdeaea;
  --serif: "Songti SC", "Noto Serif SC", "Source Han Serif SC", serif;
  --sans: -apple-system, BlinkMacSystemFont, "PingFang SC", "Hiragino Sans GB", "Noto Sans SC", "Microsoft YaHei", "Segoe UI", sans-serif;
  --mono: "SF Mono", "JetBrains Mono", "Fira Code", Menlo, Consolas, monospace;
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0; font-family: var(--sans); color: var(--ink);
  background: var(--paper); line-height: 1.7; font-size: 16px;
  -webkit-font-smoothing: antialiased; text-rendering: optimizeLegibility;
}
a { color: var(--cardinal); text-decoration: none; }
a:hover { text-decoration: underline; }

/* ---------- topbar ---------- */
.topbar {
  position: sticky; top: 0; z-index: 50; background: rgba(253, 252, 251, 0.92);
  backdrop-filter: blur(10px); border-bottom: 1px solid var(--line);
}
.topbar-inner {
  max-width: 1640px; margin: 0 auto; padding: 0 24px; height: 56px;
  display: flex; align-items: center; gap: 24px;
}
.brand {
  font-weight: 800; font-size: 18px; color: var(--ink); letter-spacing: 0.2px;
  display: flex; align-items: center; gap: 6px; white-space: nowrap;
}
.brand:hover { text-decoration: none; }
.brand-mark {
  background: var(--cardinal); color: #fff; border-radius: 6px;
  padding: 1px 7px; font-size: 14px; margin-right: 2px;
}
.brand-sub { color: var(--ink-soft); font-weight: 500; font-size: 13px; margin-left: 4px; }
.topnav { display: flex; gap: 18px; font-size: 14px; color: var(--ink-soft); }
.topnav a { color: var(--ink-soft); }
.topnav a:hover { color: var(--cardinal); }
.searchbox { margin-left: auto; position: relative; }
.searchbox input {
  width: 240px; padding: 7px 12px; border: 1px solid var(--line); border-radius: 999px;
  background: #fff; font-size: 14px; font-family: var(--sans); outline: none;
  transition: width 0.2s, border-color 0.2s;
}
.searchbox input:focus { width: 300px; border-color: var(--cardinal); }
.search-results {
  position: absolute; top: 44px; right: 0; width: 380px; max-height: 60vh; overflow: auto;
  background: #fff; border: 1px solid var(--line); border-radius: 12px;
  box-shadow: 0 12px 32px rgba(0,0,0,0.12); padding: 6px;
}
.search-results a {
  display: block; padding: 8px 12px; border-radius: 8px; color: var(--ink); font-size: 14px;
}
.search-results a:hover { background: var(--line-soft); text-decoration: none; }
.search-results .sr-week { color: var(--ink-soft); font-size: 12px; }
.search-results .sr-empty { padding: 10px 12px; color: var(--ink-soft); font-size: 14px; }

/* ---------- hero ---------- */
.hero {
  background:
    radial-gradient(1100px 400px at 85% -80px, rgba(255,255,255,0.14), transparent 60%),
    linear-gradient(135deg, var(--cardinal) 0%, var(--cardinal-dark) 55%, #4a0c0c 100%);
  color: #fff; padding: 64px 20px 56px;
}
.hero-inner { max-width: 1500px; margin: 0 auto; }
.hero-kicker {
  font-size: 13px; letter-spacing: 1.5px; text-transform: uppercase;
  color: rgba(255,255,255,0.75); margin: 0 0 14px; font-weight: 600;
}
.hero h1 {
  margin: 0 0 8px; font-size: 46px; line-height: 1.15; font-weight: 800; letter-spacing: 0.3px;
}
.hero-cn { font-size: 24px; font-weight: 600; color: rgba(255,255,255,0.92); }
.hero-desc {
  max-width: 760px; color: rgba(255,255,255,0.88); font-size: 16px; margin: 18px 0 28px;
}
.hero-desc b { color: #ffd9d9; }
.hero-stats { display: flex; gap: 14px; flex-wrap: wrap; }
.stat {
  background: rgba(255,255,255,0.1); border: 1px solid rgba(255,255,255,0.22);
  border-radius: 12px; padding: 12px 22px; text-align: center; min-width: 110px;
}
.stat b { display: block; font-size: 26px; line-height: 1.2; }
.stat span { font-size: 13px; color: rgba(255,255,255,0.8); }

/* ---------- index main ---------- */
.index-main { max-width: 1500px; margin: 0 auto; padding: 44px 24px 60px; }
.sec-title {
  font-size: 26px; margin: 10px 0 22px; padding-bottom: 10px;
  border-bottom: 3px solid var(--cardinal); display: inline-block;
}
.topic { margin: 0 0 34px; }
.topic-head { display: flex; align-items: baseline; gap: 14px; flex-wrap: wrap; margin-bottom: 6px; }
.topic-date {
  background: var(--cardinal); color: #fff; font-size: 13px; font-weight: 700;
  border-radius: 8px; padding: 3px 10px; letter-spacing: 0.5px; align-self: center;
}
.topic-head h2 { margin: 0; font-size: 22px; }
.topic-week { color: var(--ink-soft); font-size: 15px; font-weight: 500; margin-left: 6px; }
.topic-count { color: var(--ink-soft); font-size: 13px; margin-left: auto; }
.mat-list { list-style: none; margin: 0; padding: 0; }
.mat-row {
  background: var(--card); border: 1px solid var(--line); border-radius: 12px;
  padding: 14px 18px; margin-bottom: 10px; transition: box-shadow 0.15s, transform 0.15s;
}
.mat-row:hover { box-shadow: 0 6px 18px rgba(140, 21, 21, 0.08); }
.mat-link { color: var(--ink); display: flex; align-items: center; gap: 8px; flex-wrap: wrap; }
.mat-link:hover { text-decoration: none; }
.mat-link:hover .mat-title { color: var(--cardinal); }
.mat-title { font-size: 16.5px; font-weight: 650; }
.mat-sub { color: var(--ink-soft); font-size: 13px; margin-top: 3px; font-style: italic; }
.mat-summary { color: var(--ink-soft); font-size: 14px; margin-top: 5px; }

/* ---------- badges ---------- */
.badge {
  display: inline-block; font-size: 12px; font-weight: 700; border-radius: 6px;
  padding: 1.5px 8px; white-space: nowrap; line-height: 1.6;
}
.badge-must { background: var(--must-bg); color: var(--cardinal); border: 1px solid #f2c4c4; }
.badge-recommended { background: var(--amber-bg); color: var(--amber); border: 1px solid #f3d9a4; }
.badge-supplementary { background: var(--gray-bg); color: var(--gray); border: 1px solid #e2e4e7; }
.badge-kind { background: #eef4ee; color: #2f6b3a; border: 1px solid #cfe3d2; }

/* ---------- dates & about ---------- */
.dates, .about { margin-top: 48px; }
.dates-table { border-collapse: collapse; width: 100%; background: var(--card); border: 1px solid var(--line); border-radius: 12px; overflow: hidden; font-size: 15px; }
.dates-table th, .dates-table td { padding: 10px 16px; border-bottom: 1px solid var(--line-soft); text-align: left; }
.dates-table th { background: var(--line-soft); color: var(--ink-soft); font-size: 13px; letter-spacing: 1px; }
.dates-table tr:last-child td { border-bottom: none; }
.d-week { color: var(--cardinal); font-weight: 700; white-space: nowrap; }
.d-date { white-space: nowrap; color: var(--ink-soft); }
.footer {
  border-top: 1px solid var(--line); color: var(--ink-soft); font-size: 13px;
  text-align: center; padding: 26px 20px; background: #faf8f6;
}

/* ---------- reading page ---------- */
.read-layout {
  max-width: 1720px; margin: 0 auto; padding: 30px 28px 60px;
  display: grid; grid-template-columns: 250px minmax(0, 1fr); gap: 48px;
}
.read-toc { position: sticky; top: 76px; align-self: start; max-height: calc(100vh - 100px); overflow: auto; font-size: 13.5px; }
.read-toc-title { font-weight: 700; color: var(--ink-soft); font-size: 12px; letter-spacing: 1.5px; margin-bottom: 8px; }
.read-toc ul { list-style: none; margin: 0; padding: 0; border-left: 2px solid var(--line); }
.read-toc li { margin: 0; }
.read-toc a { display: block; padding: 4px 0 4px 14px; color: var(--ink-soft); border-left: 2px solid transparent; margin-left: -2px; }
.read-toc ul ul a { padding-left: 28px; font-size: 12.5px; }
.read-toc a:hover { color: var(--cardinal); text-decoration: none; }
.crumb { font-size: 13px; color: var(--ink-soft); margin-bottom: 18px; }
.crumb a { color: var(--ink-soft); }
.read-article { background: var(--card); border: 1px solid var(--line); border-radius: 16px; padding: 44px 56px 34px; }
.read-title { font-size: 30px; line-height: 1.35; margin: 0 0 6px; }
.read-title-en { color: var(--ink-soft); font-size: 15.5px; font-style: italic; margin: 0 0 10px; }
.read-meta { color: var(--ink-soft); font-size: 14px; margin: 0 0 12px; }
.read-badges { display: flex; align-items: center; gap: 8px; margin: 0 0 8px; padding-bottom: 18px; border-bottom: 1px solid var(--line-soft); flex-wrap: wrap; }
.orig-link { font-size: 13.5px; margin-left: auto; font-weight: 600; }

.pager { display: flex; gap: 12px; margin-top: 20px; }
.pager a {
  flex: 1; background: var(--card); border: 1px solid var(--line); border-radius: 12px;
  padding: 12px 16px; color: var(--ink); font-size: 14.5px;
}
.pager a:hover { border-color: var(--cardinal); text-decoration: none; }
.pager a span { display: block; font-size: 12px; color: var(--ink-soft); margin-bottom: 2px; }
.pager-next { text-align: right; }

/* ---------- markdown body ---------- */
.markdown-body { font-size: 16px; line-height: 1.85; }
.markdown-body h2 {
  font-size: 21px; margin: 34px 0 14px; padding: 8px 0 8px 14px;
  border-left: 4px solid var(--cardinal); background: linear-gradient(90deg, #faf1f0, transparent 70%);
  border-radius: 2px;
}
.markdown-body h3 { font-size: 17.5px; margin: 26px 0 10px; color: var(--cardinal-ink); }
.markdown-body h4 { font-size: 16px; margin: 20px 0 8px; }
.markdown-body p { margin: 12px 0; }
.markdown-body ul, .markdown-body ol { padding-left: 1.6em; margin: 12px 0; }
.markdown-body li { margin: 5px 0; }
.markdown-body blockquote {
  margin: 16px 0; padding: 10px 18px; border-left: 4px solid var(--line);
  background: var(--line-soft); border-radius: 0 8px 8px 0; color: var(--ink-soft);
}
.markdown-body code {
  font-family: var(--mono); font-size: 0.88em; background: var(--gray-bg);
  border-radius: 5px; padding: 1.5px 6px; color: #b3403f;
}
.markdown-body pre {
  background: #23272e; color: #e6edf3; border-radius: 12px; padding: 18px 20px;
  overflow-x: auto; line-height: 1.6; font-size: 13.5px; margin: 16px 0;
}
.markdown-body pre code { background: none; padding: 0; color: inherit; font-size: inherit; }
.markdown-body table { border-collapse: collapse; width: 100%; margin: 16px 0; font-size: 14.5px; display: block; overflow-x: auto; }
.markdown-body th, .markdown-body td { border: 1px solid var(--line); padding: 8px 12px; text-align: left; }
.markdown-body th { background: var(--line-soft); }
.markdown-body hr { border: none; border-top: 1px solid var(--line); margin: 28px 0; }
.markdown-body strong { color: var(--cardinal-ink); }

/* ---------- responsive ---------- */
@media (max-width: 960px) {
  .read-layout { grid-template-columns: 1fr; gap: 0; }
  .read-toc { display: none; }
  .hero h1 { font-size: 34px; }
  .hero-cn { font-size: 19px; }
  .searchbox input { width: 150px; }
  .searchbox input:focus { width: 190px; }
  .read-article { padding: 26px 22px; }
  .topnav { display: none; }
}
@media print {
  .topbar, .read-toc, .pager, .searchbox { display: none !important; }
  .read-article { border: none; padding: 0; }
  .read-layout { display: block; }
}

/* ---------- 中英对照 ---------- */
.en-orig {
  background: #f4f5f7; border-left: 3px solid #b0b6bf; border-radius: 0 8px 8px 0;
  padding: 10px 16px 12px; margin: 16px 0 4px; color: #4a5160;
  font-family: Georgia, "Times New Roman", "Source Serif 4", serif;
  font-size: 14.5px; line-height: 1.65;
}
.en-orig .en-tag {
  display: inline-block; font-size: 10.5px; font-weight: 700; color: #6b7280;
  border: 1px solid #ccd1d8; border-radius: 4px; padding: 0 6px;
  letter-spacing: 1.5px; margin-bottom: 4px; font-family: var(--sans);
}
.en-orig p { margin: 2px 0 0; }
.markdown-body .en-orig + p { margin-top: 4px; font-weight: 500; }
body.zh-only .en-orig { display: none; }
.lang-toggle {
  font-size: 12.5px; font-weight: 600; color: var(--cardinal); background: #fff;
  border: 1px solid #e5b8b8; border-radius: 999px; padding: 2px 12px; cursor: pointer;
  font-family: var(--sans); transition: background 0.15s;
}
.lang-toggle:hover { background: var(--must-bg); }

/* 全译进度提示 */
.bi-progress {
  background: #eef4ee; border: 1px solid #cfe3d2; border-radius: 10px;
  padding: 10px 16px; font-size: 14px; color: #33503a; margin: 0 0 26px;
}
.bi-progress b { font-size: 16px; }

/* 数学公式 */
.math-display { text-align: center; margin: 14px 0; overflow-x: auto; }
.math-inline code, .math-inline { white-space: normal; }

/* ---------- 中英对照:宽屏左右分栏 ---------- */
@media (min-width: 1240px) {
  .pair {
    display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
    gap: 26px; align-items: start; margin: 14px 0;
  }
  .pair .en-orig { margin: 0; }
  .pair > p {
    margin: 0; padding: 10px 2px 10px 18px; font-weight: 500;
    border-left: 3px solid #e3d5c6; border-radius: 0 2px 2px 0;
  }
  .read-article { padding: 44px 64px 34px; }
  .markdown-body { font-size: 16.5px; }
}

/* ---------- 主题大类导航与分组 ---------- */
.cat-nav { position: sticky; top: 56px; z-index: 40; background: rgba(253,252,251,0.95); backdrop-filter: blur(8px); border-bottom: 1px solid var(--line); }
.cat-nav-inner { max-width: 1500px; margin: 0 auto; padding: 10px 24px; display: flex; flex-wrap: wrap; gap: 8px; }
.cat-nav a { font-size: 13.5px; color: var(--ink-soft); background: #fff; border: 1px solid var(--line); border-radius: 999px; padding: 3px 14px; white-space: nowrap; }
.cat-nav a:hover { color: var(--cardinal); border-color: var(--cardinal); text-decoration: none; }
.cat-section { margin: 40px 0 10px; }
.cat-head { display: flex; gap: 16px; align-items: center; padding: 14px 18px; background: linear-gradient(90deg, #faf1f0, #fbf8f5 70%); border: 1px solid #efdcdc; border-radius: 14px; margin-bottom: 16px; }
.cat-no { font-size: 22px; font-weight: 800; color: var(--cardinal); opacity: .55; font-variant-numeric: tabular-nums; }
.cat-title { margin: 0; font-size: 22px; }
.cat-desc { margin: 2px 0 0; color: var(--ink-soft); font-size: 13.5px; }
.all-mats { font-size: 14px; font-weight: 600; margin-left: 18px; vertical-align: middle; }

/* ---------- 材料总目录页 ---------- */
.hero-compact { padding: 40px 20px 36px; }
.materials-main { max-width: 1500px; margin: 0 auto; padding: 26px 24px 60px; }
.filter-bar { background: #fff; border-bottom: 1px solid var(--line); }
.filter-bar > div { max-width: 1500px; margin: 0 auto; padding: 10px 24px; display: flex; align-items: center; gap: 8px; flex-wrap: wrap; }
.fb-group b { font-size: 13px; color: var(--ink-soft); margin-right: 4px; }
.filter-bar button { font-size: 13px; font-family: var(--sans); border: 1px solid var(--line); background: #fff; color: var(--ink-soft); border-radius: 999px; padding: 3px 14px; cursor: pointer; }
.filter-bar button.on { background: var(--cardinal); border-color: var(--cardinal); color: #fff; }
.mat-cat { margin: 28px 0; }
.mat-cat-title { font-size: 19px; margin: 0 0 10px; display: flex; align-items: center; gap: 10px; }
.mat-cat-count { font-size: 13px; color: var(--ink-soft); font-weight: 400; }
.mat-table { width: 100%; border-collapse: collapse; background: var(--card); border: 1px solid var(--line); border-radius: 12px; overflow: hidden; font-size: 14.5px; }
.mat-table th { text-align: left; background: var(--line-soft); color: var(--ink-soft); font-size: 12.5px; letter-spacing: 1px; padding: 8px 14px; }
.mat-table td { padding: 9px 14px; border-top: 1px solid var(--line-soft); vertical-align: top; }
.mat-table a { font-weight: 600; }
.mt-sub { color: var(--ink-soft); font-size: 12.5px; font-style: italic; margin-top: 2px; }
.mt-week { color: var(--ink-soft); font-size: 13px; white-space: nowrap; }