/* ============ 实验梦工场 LabWorks — 前台共享样式 ============ */
:root {
  --primary: #2563eb;
  --primary-dark: #1d4ed8;
  --primary-light: #dbeafe;
  --accent: #f59e0b;
  --success: #16a34a;
  --danger: #dc2626;
  --text: #1e293b;
  --text-secondary: #64748b;
  --bg: #f8fafc;
  --card: #ffffff;
  --border: #e2e8f0;
  --radius: 12px;
  --shadow: 0 1px 3px rgba(15, 23, 42, .08), 0 4px 16px rgba(15, 23, 42, .06);
}
* { margin: 0; padding: 0; box-sizing: border-box; }
body {
  font-family: "PingFang SC", "Microsoft YaHei", "Segoe UI", sans-serif;
  background: var(--bg); color: var(--text); line-height: 1.6;
}
a { color: inherit; text-decoration: none; }
img { max-width: 100%; }
.container { max-width: 1200px; margin: 0 auto; padding: 0 24px; }

/* ---------- 顶部导航（对应草图 header） ---------- */
.navbar {
  background: #fff; border-bottom: 1px solid var(--border);
  position: sticky; top: 0; z-index: 100;
}
.navbar-inner {
  max-width: 1200px; margin: 0 auto; padding: 0 24px;
  height: 64px; display: flex; align-items: center; gap: 32px;
}
.logo { display: flex; align-items: center; gap: 10px; font-size: 20px; font-weight: 700; }
.logo-badge {
  width: 36px; height: 36px; border-radius: 10px;
  background: linear-gradient(135deg, #2563eb, #7c3aed);
  color: #fff; display: flex; align-items: center; justify-content: center;
  font-size: 18px;
}
.nav-menu { display: flex; align-items: center; gap: 8px; flex: 1; }
.nav-item { position: relative; }
.nav-link {
  display: flex; align-items: center; gap: 4px;
  padding: 8px 14px; border-radius: 8px; font-size: 15px; cursor: pointer;
  transition: background .15s;
}
.nav-link:hover, .nav-item.open .nav-link { background: var(--primary-light); color: var(--primary-dark); }
.caret { font-size: 10px; color: var(--text-secondary); }
.dropdown {
  position: absolute; top: calc(100% + 6px); left: 0;
  background: #fff; border: 1px solid var(--border); border-radius: 10px;
  box-shadow: var(--shadow); min-width: 180px; padding: 6px;
  display: none;
}
.nav-item.open .dropdown { display: block; }
.dropdown a {
  display: block; padding: 9px 14px; border-radius: 8px; font-size: 14px;
}
.dropdown a:hover { background: var(--primary-light); color: var(--primary-dark); }

/* 二级菜单：分类分组（一级=菜单，二级=分类分组→具体项目） */
.dropdown { padding-bottom: 8px; }
.menu-group-label {
  font-size: 12px; color: var(--text-secondary); font-weight: 600;
  letter-spacing: .06em; padding: 10px 14px 4px; display: flex; align-items: center; gap: 6px;
}
.menu-group-label::after {
  content: ""; flex: 1; height: 1px; background: var(--border);
}
.menu-group a { display: flex; align-items: center; gap: 8px; padding-left: 26px; font-size: 13.5px; }
.menu-group .price-tag { margin-left: auto; font-size: 11px; color: #b45309; }
.menu-group .free-tag { margin-left: auto; font-size: 11px; color: #15803d; }

/* 大型二级菜单（mega menu）：左侧一级菜单 → 右侧二级分类列表，面板独立显示在导航下方。
   二级只到大类，不出现具体课程/实验与价格标记；点分类进入该分类的列表页 */
.mega {
  position: absolute; top: calc(100% + 6px); left: 0;
  display: none; background: #fff;
  border: 1px solid var(--border); border-radius: 12px;
  box-shadow: 0 16px 40px rgba(15, 23, 42, .14);
  width: 560px; overflow: hidden; z-index: 60;
}
.nav-item.open .mega { display: flex; }
.mega-side {
  width: 190px; flex-shrink: 0;
  background: #f8fafc; border-right: 1px solid var(--border);
  padding: 10px 0;
}
.mega-side-item {
  padding: 12px 16px; font-size: 14.5px; font-weight: 600; cursor: pointer;
  display: block;
  border-left: 3px solid transparent; transition: background .12s;
}
.mega-side-item:hover, .mega-side-item.active {
  background: #eef2ff; border-left-color: var(--primary); color: var(--primary-dark);
}
.mega-body { flex: 1; padding: 16px 20px; min-height: 220px; }
.mega-pane { display: none; }
.mega-pane.active { display: block; }
.mega-pane-title {
  font-size: 13px; color: var(--text-secondary); font-weight: 600;
  padding-bottom: 8px; margin-bottom: 6px; border-bottom: 1px solid var(--border);
  display: flex; align-items: center; gap: 6px;
}
.mega-pane > a {
  display: flex; align-items: center; gap: 8px;
  padding: 10px 10px; border-radius: 8px; font-size: 14.5px;
}
.mega-pane > a:hover { background: var(--primary-light); color: var(--primary-dark); }


/* 搜索框（对应草图 搜索框 + 搜索按钮） */
.search-box { display: flex; align-items: center; gap: 8px; }
.search-box input {
  width: 220px; height: 38px; border: 1px solid var(--border);
  border-radius: 999px; padding: 0 16px; font-size: 14px; outline: none;
  transition: border .15s, box-shadow .15s;
}
.search-box input:focus { border-color: var(--primary); box-shadow: 0 0 0 3px var(--primary-light); }
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 6px;
  border: none; cursor: pointer; font-size: 14px; white-space: nowrap;
  border-radius: 999px; padding: 9px 20px; transition: .15s; font-family: inherit;
}
.btn-primary { background: var(--primary); color: #fff; }
.btn-primary:hover { background: var(--primary-dark); }
.btn-outline { background: transparent; color: var(--primary); border: 1px solid var(--primary); }
.btn-outline:hover { background: var(--primary-light); }
.btn-ghost { background: transparent; color: var(--text-secondary); }
.btn-ghost:hover { background: var(--bg); color: var(--text); }
.btn-round { width: 38px; height: 38px; padding: 0; border-radius: 50%; }
.auth-links { display: flex; gap: 6px; }

/* ---------- 区块 ---------- */
.section { padding: 40px 0; }
.section-header { display: flex; align-items: center; justify-content: space-between; margin-bottom: 22px; }
.section-title { font-size: 24px; font-weight: 700; display: flex; align-items: center; gap: 10px; }
.section-title::before {
  content: ""; width: 5px; height: 24px; border-radius: 3px;
  background: linear-gradient(180deg, var(--primary), #7c3aed);
}
.section-more { color: var(--primary); font-size: 14px; }
.section-more:hover { text-decoration: underline; }

/* 卡片网格（对应草图 图标+文字 卡片） */
.card-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(250px, 1fr)); gap: 20px; }
.card {
  background: var(--card); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 26px 22px; box-shadow: var(--shadow); cursor: pointer;
  transition: transform .18s, box-shadow .18s, border-color .18s;
  display: block; position: relative;
}
.card:hover { transform: translateY(-4px); border-color: var(--primary); box-shadow: 0 8px 24px rgba(37, 99, 235, .12); }
.card-icon {
  width: 52px; height: 52px; border-radius: 14px; display: flex;
  align-items: center; justify-content: center; font-size: 26px; margin-bottom: 14px;
}
.card-title { font-size: 17px; font-weight: 600; margin-bottom: 6px; }
.card-desc { font-size: 13px; color: var(--text-secondary); margin-bottom: 12px; }
.card-meta { display: flex; gap: 14px; font-size: 12px; color: var(--text-secondary); }
/* 卡片封面区（首页 / 实验室列表 / 课程列表共用，labs.html 与 courses.html 也有同值局部定义）：
   后台上传了封面图 → 图片铺满裁切；未上传 → 纯色背景 + emoji 图标 */
.card .cover {
  height: 120px; border-radius: 10px; margin-bottom: 14px;
  display: flex; align-items: center; justify-content: center; font-size: 44px;
}
.tag {
  display: inline-block; font-size: 12px; padding: 2px 10px; border-radius: 999px;
  background: var(--primary-light); color: var(--primary-dark);
}
.tag-green { background: #dcfce7; color: #15803d; }
.tag-orange { background: #fef3c7; color: #b45309; }

/* ---------- Hero ---------- */
.hero {
  background: linear-gradient(120deg, #1e3a8a 0%, #2563eb 55%, #7c3aed 100%);
  color: #fff; padding: 72px 0 84px; text-align: center;
}
.hero h1 { font-size: 40px; margin-bottom: 14px; }
.hero p { font-size: 17px; opacity: .88; max-width: 620px; margin: 0 auto 30px; }
.hero .search-box input { width: 420px; border: none; }
.hero .btn-outline { border-color: #fff; color: #fff; }
.hero .btn-outline:hover { background: rgba(255,255,255,.15); }
.hero-stats { display: flex; justify-content: center; gap: 56px; margin-top: 44px; }
.hero-stat b { font-size: 26px; display: block; }
.hero-stat span { font-size: 13px; opacity: .8; }

/* ---------- 面包屑 / 页面头 ---------- */
.page-head { background: #fff; border-bottom: 1px solid var(--border); padding: 20px 0; }
.breadcrumb { font-size: 13px; color: var(--text-secondary); }
.breadcrumb a { color: var(--primary); }
.page-head h1, .page-head h2 { font-size: 22px; margin-top: 6px; font-weight: 700; }

/* ---------- 布局：侧栏 + 内容 ---------- */
.layout { display: grid; grid-template-columns: 240px 1fr; gap: 24px; padding: 24px 0 60px; }
.side-panel { background: #fff; border: 1px solid var(--border); border-radius: var(--radius); padding: 16px; height: fit-content; position: sticky; top: 84px; }
.side-title { font-size: 13px; font-weight: 600; color: var(--text-secondary); padding: 6px 10px; letter-spacing: .05em; }
.side-panel a {
  display: flex; align-items: center; gap: 10px; padding: 10px 12px;
  border-radius: 8px; font-size: 14px; margin-bottom: 2px;
}
.side-panel a:hover { background: var(--bg); }
.side-panel a.active { background: var(--primary-light); color: var(--primary-dark); font-weight: 600; }

/* ---------- 通用组件 ---------- */
.panel { background: #fff; border: 1px solid var(--border); border-radius: var(--radius); padding: 24px; box-shadow: var(--shadow); }
.panel + .panel { margin-top: 20px; }
.panel h3 { font-size: 18px; margin-bottom: 14px; }
table.data-table { width: 100%; border-collapse: collapse; font-size: 14px; }
.data-table th, .data-table td { text-align: left; padding: 12px 14px; border-bottom: 1px solid var(--border); }
.data-table th { color: var(--text-secondary); font-weight: 600; font-size: 13px; background: var(--bg); }
.data-table tr:hover td { background: #f1f5f9; }
.pill {
  display: inline-block; padding: 2px 10px; border-radius: 999px; font-size: 12px; font-weight: 500;
}
.pill-green { background: #dcfce7; color: #15803d; }
.pill-red { background: #fee2e2; color: #b91c1c; }
.pill-gray { background: #e2e8f0; color: #475569; }
.pill-blue { background: #dbeafe; color: #1d4ed8; }

/* 终端模拟器 */
.terminal {
  background: #0f172a; border-radius: var(--radius); color: #e2e8f0;
  font-family: Consolas, "Courier New", monospace; font-size: 14px;
  padding: 0; overflow: hidden;
}
.terminal-bar {
  background: #1e293b; padding: 10px 14px; display: flex; align-items: center; gap: 8px;
}
.dot { width: 12px; height: 12px; border-radius: 50%; }
.dot-r { background: #ef4444; } .dot-y { background: #eab308; } .dot-g { background: #22c55e; }
.terminal-bar span.t-title { margin-left: 10px; font-size: 12px; color: #94a3b8; }
.terminal-body { padding: 16px; height: 380px; overflow-y: auto; }
.terminal-body .line { white-space: pre-wrap; margin-bottom: 2px; }
.terminal-input-row { display: flex; gap: 8px; padding: 12px 16px; background: #1e293b; }
.terminal-input-row .prompt { color: #22c55e; font-family: inherit; font-size: 14px; white-space: nowrap; }
.terminal-input-row input {
  flex: 1; background: transparent; border: none; outline: none;
  color: #e2e8f0; font-family: inherit; font-size: 14px;
}
.prompt-user { color: #22c55e; }
.prompt-path { color: #60a5fa; }

/* 进度条 */
.progress { height: 8px; background: var(--border); border-radius: 999px; overflow: hidden; }
.progress > i { display: block; height: 100%; background: var(--primary); border-radius: 999px; }

/* 算法可视化 */
.algo-stage {
  background: #fff; border: 1px solid var(--border); border-radius: var(--radius);
  padding: 30px 20px; display: flex; align-items: flex-end; justify-content: center;
  gap: 6px; height: 300px;
}
.algo-bar {
  width: 34px; background: var(--primary); border-radius: 6px 6px 0 0;
  position: relative; transition: height .25s, background .15s;
  display: flex; justify-content: center;
}
.algo-bar span {
  position: absolute; top: -22px; font-size: 12px; color: var(--text-secondary);
}
.algo-bar.compare { background: #f59e0b; }
.algo-bar.swap { background: #dc2626; }
.algo-bar.sorted { background: #16a34a; }
.algo-controls { display: flex; gap: 10px; align-items: center; flex-wrap: wrap; margin-top: 18px; }
.log-panel {
  background: #0f172a; color: #a5b4fc; border-radius: 10px; padding: 14px;
  font-family: Consolas, monospace; font-size: 13px; height: 150px; overflow-y: auto; margin-top: 16px;
}

/* 课程详情 */
.video-placeholder {
  background: linear-gradient(135deg, #1e293b, #334155); border-radius: var(--radius);
  height: 420px; display: flex; align-items: center; justify-content: center;
  color: #94a3b8; font-size: 16px; position: relative;
}
.play-btn {
  width: 72px; height: 72px; border-radius: 50%; background: rgba(255,255,255,.12);
  border: 2px solid rgba(255,255,255,.4); display: flex; align-items: center;
  justify-content: center; font-size: 26px; color: #fff; cursor: pointer;
}
.chapter-list li {
  display: flex; align-items: center; gap: 12px; padding: 13px 10px;
  border-bottom: 1px solid var(--border); cursor: pointer; border-radius: 8px;
}
.chapter-list li:hover { background: var(--bg); }
.chapter-list li.active { background: var(--primary-light); }
.chapter-list .no {
  width: 26px; height: 26px; border-radius: 50%; background: var(--border);
  display: flex; align-items: center; justify-content: center; font-size: 12px; flex-shrink: 0;
}
.chapter-list li.active .no { background: var(--primary); color: #fff; }

/* 文档中心 */
.doc-item { display: flex; gap: 14px; padding: 18px 6px; border-bottom: 1px solid var(--border); }
.doc-item:last-child { border-bottom: none; }
.doc-icon {
  width: 42px; height: 42px; border-radius: 10px; flex-shrink: 0;
  display: flex; align-items: center; justify-content: center; font-size: 20px;
}
.doc-item h4 { font-size: 16px; }
.doc-item p { font-size: 13px; color: var(--text-secondary); margin: 4px 0 8px; }
.doc-item .meta { font-size: 12px; color: var(--text-secondary); display: flex; gap: 16px; }

/* 登录页 */
.auth-wrap {
  min-height: calc(100vh - 64px); display: flex; align-items: center; justify-content: center;
  background: linear-gradient(120deg, #eff6ff, #f5f3ff);
}
.auth-card {
  background: #fff; border-radius: 16px; box-shadow: var(--shadow);
  width: 420px; padding: 40px 36px;
}
.auth-card h2 { text-align: center; margin-bottom: 6px; }
.auth-card .sub { text-align: center; color: var(--text-secondary); font-size: 14px; margin-bottom: 26px; }
.form-group { margin-bottom: 18px; }
.form-group label { display: block; font-size: 13px; margin-bottom: 6px; color: var(--text-secondary); }
.form-group input, .form-group select, .form-group textarea {
  width: 100%; height: 42px; border: 1px solid var(--border); border-radius: 10px;
  padding: 0 14px; font-size: 14px; outline: none; font-family: inherit;
  transition: border .15s, box-shadow .15s;
}
.form-group textarea { height: auto; padding: 10px 14px; }
.form-group input:focus, .form-group select:focus, .form-group textarea:focus {
  border-color: var(--primary); box-shadow: 0 0 0 3px var(--primary-light);
}
.form-row { display: flex; justify-content: space-between; align-items: center; font-size: 13px; margin-bottom: 20px; }
.form-row a { color: var(--primary); }
.btn-block { width: 100%; height: 44px; border-radius: 10px; font-size: 15px; }
.auth-switch { text-align: center; font-size: 13px; color: var(--text-secondary); margin-top: 18px; }
.auth-switch a { color: var(--primary); }

/* 页脚 */
.footer { background: #0f172a; color: #94a3b8; padding: 36px 0; margin-top: 60px; }
.footer-inner { max-width: 1200px; margin: 0 auto; padding: 0 24px; display: flex; justify-content: space-between; flex-wrap: wrap; gap: 20px; }
.footer a { color: #cbd5e1; margin-right: 18px; font-size: 14px; }
.footer a:hover { color: #fff; }
.footer .copyright { font-size: 13px; margin-top: 10px; }

/* Toast */
.toast {
  position: fixed; top: 80px; left: 50%; transform: translateX(-50%) translateY(-16px);
  background: #1e293b; color: #fff; padding: 10px 22px; border-radius: 999px;
  font-size: 14px; opacity: 0; pointer-events: none; transition: .25s; z-index: 999;
}
.toast.show { opacity: 1; transform: translateX(-50%) translateY(0); }

/* 移动端汉堡按钮（由 main.js 注入 .navbar-inner；桌面端隐藏） */
.nav-toggle { display:none; }

@media (max-width: 900px) {
  .layout { grid-template-columns: 1fr; }

  /* ---------- 顶部导航：折叠为两行布局，菜单收进汉堡按钮 ---------- */
  .navbar-inner {
    height: auto; flex-wrap: wrap; gap: 10px 12px; padding: 10px 14px;
  }
  .logo { flex: 1; min-width: 0; font-size: 17px; white-space: nowrap; }
  .logo-badge { width: 30px; height: 30px; font-size: 15px; flex: none; }
  /* 小屏隐藏 "LabWorks" 副标（注意要用 :not() 排除 .logo-badge，
     否则连左上角的 ⚗ 图标一起被干掉） */
  .logo > span:not(.logo-badge) { display: none; }
  .nav-toggle {
    display: inline-flex; align-items: center; justify-content: center;
    width: 38px; height: 38px; flex: none;
    border: 1px solid var(--border); border-radius: 10px; background: #fff;
    color: var(--text); font-size: 18px; cursor: pointer;
  }
  .auth-links { flex: none; }
  .auth-links .btn { padding: 8px 14px; font-size: 13px; }
  /* 顶部搜索框独占一行（search.html 的搜索功能依赖它，不能隐藏；输入框弹性占满、按钮不变形） */
  .navbar .search-box { order: 4; flex-basis: 100%; }
  .navbar .search-box input { flex: 1; width: auto; min-width: 0; }
  /* 首页已有 Hero 大搜索框，顶部搜索行属重复，支持的浏览器上隐藏（:has 渐进增强，不支持则照常显示） */
  body:has(.hero) .navbar .search-box { display: none; }

  /* 菜单区：默认收起，点汉堡后纵向铺满第二行 */
  .nav-menu {
    display: none; order: 5; flex-basis: 100%;
    flex-direction: column; align-items: stretch; gap: 2px; padding-bottom: 6px;
  }
  .navbar.open .nav-menu { display: flex; }
  .nav-item { width: 100%; }
  .nav-link { padding: 11px 12px; font-size: 15px; }

  /* mega 大菜单：小屏改为普通堆叠面板（不再绝对定位、不再左右两栏） */
  .mega {
    position: static; width: 100%; flex-direction: column;
    border: none; border-radius: 0; box-shadow: none;
    border-top: 1px solid var(--border); overflow: visible;
  }
  .nav-item.open .mega { display: flex; }
  .mega-side {
    width: 100%; display: flex; flex-wrap: wrap; gap: 4px;
    padding: 8px; border-right: none; border-bottom: 1px solid var(--border);
  }
  .mega-side-item { border-left: none; border-radius: 8px; padding: 8px 12px; font-size: 13.5px; }
  .mega-body { padding: 10px 12px; min-height: 0; }
  .mega-pane > a { padding: 10px 8px; }

  /* ---------- Hero ---------- */
  .hero { padding: 44px 16px 56px; }
  .hero h1 { font-size: 26px; }
  .hero p { font-size: 15px; }
  /* 搜索框整体一行：输入框弹性占满、按钮保持自然宽度（修复按钮被挤成竖条） */
  .hero .search-box { width: 100%; max-width: 460px; margin: 0 auto; }
  .hero .search-box input { flex: 1; width: auto; min-width: 0; }
  .hero-stats { gap: 26px; margin-top: 32px; flex-wrap: wrap; }

  /* ---------- 区块 / 卡片 / 容器 ---------- */
  .container { padding: 0 16px; }
  .section { padding: 28px 0; }
  .section-title { font-size: 20px; }
  .card { padding: 18px 16px; }

  /* ---------- 登录卡 / 页脚 ---------- */
  .auth-wrap { padding: 24px 14px; }
  .auth-card { width: 100%; max-width: 420px; padding: 28px 22px; }
  .footer-inner { flex-direction: column; }

  /* ---------- 页面头（面包屑可能较长，字号收紧） ---------- */
  .page-head { padding: 14px 0; }
  .page-head h1, .page-head h2 { font-size: 19px; }
  .breadcrumb { font-size: 12.5px; }

  /* ---------- 侧栏（文档分类 / 课程章节）----------
     小屏单列后侧栏会跑到内容上方，若仍 sticky 就会变成一条通栏吸顶块，
     一直挂在屏幕上遮挡内容，所以小屏一律取消吸顶与最小高度限制 */
  .side-panel { position: static; top: auto; }
  .layout { gap: 16px; padding: 16px 0 44px; }

  /* ---------- 内容面板：24px 内边距在 360px 屏上只剩约 310px，收紧一档 ---------- */
  .panel { padding: 18px 16px; }
  .panel h3 { font-size: 17px; }

  /* ---------- 模拟终端 ----------
     固定 380px 高度在手机上会顶掉大半个屏幕；标题栏改为可换行，
     长标题按可用宽度省略，不再把「重置实验环境」按钮挤出容器 */
  .terminal-body { height: 300px; max-height: 52vh; }
  .terminal-bar { flex-wrap: wrap; row-gap: 6px; }
  .terminal-bar span.t-title {
    flex: 1; min-width: 0; margin-left: 6px;
    overflow: hidden; text-overflow: ellipsis; white-space: nowrap;
  }
  .terminal-input-row .prompt { font-size: 13px; }

  /* ---------- 课程详情视频占位（420px 固定高度小屏过高） ---------- */
  .video-placeholder { height: auto; min-height: 210px; padding: 24px 14px; }

  /* ---------- 文档列表条目 ---------- */
  .doc-item { gap: 10px; padding: 14px 0; }
  .doc-item .meta { flex-wrap: wrap; gap: 4px 14px; }
}

/* ---------- 更窄的手机（≤560px）：进一步收紧尺寸 ---------- */
@media (max-width: 560px) {
  .container { padding: 0 14px; }
  .logo { font-size: 16px; }

  .section { padding: 24px 0; }
  .section-title { font-size: 18px; }
  .section-title::before { height: 20px; }
  .section-more { font-size: 13px; }

  .card-grid { gap: 14px; }
  .card { padding: 16px 14px; }
  .card .cover { height: 104px; font-size: 38px; }
  .card-title { font-size: 16px; }

  .hero { padding: 34px 14px 42px; }
  .hero h1 { font-size: 23px; }
  .hero p { font-size: 14px; margin-bottom: 22px; }
  .hero-stats { gap: 18px 26px; margin-top: 26px; }
  .hero-stat b { font-size: 22px; }
  .hero-stat span { font-size: 12px; }

  .panel { padding: 16px 14px; }
  .auth-card { padding: 26px 18px; }
  .footer { padding: 26px 0; margin-top: 40px; }
  .toast { max-width: calc(100vw - 28px); text-align: center; white-space: normal; }

  .data-table { font-size: 13px; }
  .data-table th, .data-table td { padding: 9px 10px; }
}

/* ---------- 极窄屏（≤380px，如 iPhone SE / 老安卓）----------
   首页导航行是「logo + 登录 + 注册 + 汉堡」，按 390px 算刚好放得下，
   再窄 20px 就会把 logo 文字挤到溢出，这里再收紧一档 */
@media (max-width: 380px) {
  .logo { font-size: 15px; gap: 7px; }
  .logo-badge { width: 27px; height: 27px; font-size: 14px; }
  .auth-links { gap: 4px; }
  .auth-links .btn { padding: 7px 10px; font-size: 12.5px; }
  .nav-toggle { width: 34px; height: 34px; font-size: 16px; }
  .hero h1 { font-size: 21px; }
  .hero-stats { gap: 14px 20px; }
}

/* 卡片封面背景图（后台创建/编辑课程与实验室时可上传，建议 16:9 如 640×360）：
   有图时整块以图片铺满裁切显示，隐藏 emoji；无图时保持纯色背景 + emoji */
.cover.cover-img,
.card-icon.cover-img {
  background-size: cover;
  background-position: center;
  font-size: 0;
  color: transparent;
}

/* ---------- Markdown 渲染样式（参考答案等） ---------- */
.md-body { font-size: 14px; color: var(--text-secondary); line-height: 1.8; }
/* lwMD 输出配套样式（2026-10-28 收敛）：lwMD 现在统一把输出包在 <div class="lwmd"> 里，
   以下规则一律用 .lwmd 作用域，页面容器（.md-body/.lesson-md/.doc-view）只负责字号行距
   等页面级排版，Markdown 元素样式在此处一处维护。 */
.lwmd h3, .lwmd h4, .lwmd h5, .lwmd h6 { color: var(--text); margin: 12px 0 6px; }
.lwmd h3 { font-size: 16px; }
.lwmd h4 { font-size: 15px; }
.lwmd p { margin: 6px 0; }
.lwmd ul, .lwmd ol { margin: 6px 0 6px 20px; }
.lwmd li { margin: 3px 0; }
.lwmd code {
  background: var(--bg); border: 1px solid var(--border); border-radius: 5px;
  padding: 1px 6px; font-size: 13px; color: #be185d; font-family: Menlo, Consolas, monospace;
}
.lwmd .md-pre {
  background: #0f172a; color: #e2e8f0; border-radius: 10px;
  padding: 12px 14px; overflow-x: auto; margin: 8px 0; font-size: 13px; line-height: 1.6;
}
.lwmd .md-pre code { background: none; border: none; color: inherit; padding: 0; }
/* 水平分割线（此前全站无样式，靠浏览器默认） */
.lwmd hr { border: none; border-top: 1px solid var(--border); margin: 14px 0; }
/* ---------- 左侧菜单收起/展开（实验页通用） ---------- */
/* 展开时：按钮吸附在侧栏右缘（位置由 JS 计算）；收起时：固定在屏幕左缘 */
.side-toggle-btn {
  position: fixed; top: 50%; transform: translateY(-50%);
  z-index: 60; width: 18px; height: 56px; padding: 0;
  border: 1px solid var(--border); border-left: none;
  border-radius: 0 8px 8px 0; background: #fff; color: var(--text-secondary);
  cursor: pointer; font-size: 11px; line-height: 1;
  box-shadow: 2px 0 10px rgba(15, 23, 42, .08); transition: color .15s;
}
.side-toggle-btn:hover { color: var(--primary); border-color: var(--primary); }
.side-toggle-btn.at-edge {
  left: 0 !important; width: 24px; height: 60px;
  border-radius: 0 10px 10px 0;
}
.layout.side-collapsed { grid-template-columns: 1fr; }
.layout.side-collapsed .side-panel { display: none; }
/* ---------- 实验拓扑画布 ---------- */
.topo-canvas {
  background: #f8fafc; border: 1px solid var(--border); border-radius: 12px; padding: 12px;
}
.topo-canvas svg { width: 100%; height: auto; display: block; }
/* 拓扑图：透明区域用浅棋盘格衬底（白底/透明底的导出图铺在白面板上会“看不见”，易被误判为破图）；
   小图按原始尺寸居中显示，不被拉伸放大成模糊块 */
.topo-canvas img {
  max-width: 100%; height: auto; margin: 0 auto; display: block; border-radius: 8px;
  background-color: #fff;
  background-image:
    linear-gradient(45deg, #eef2f7 25%, transparent 25%, transparent 75%, #eef2f7 75%),
    linear-gradient(45deg, #eef2f7 25%, transparent 25%, transparent 75%, #eef2f7 75%);
  background-size: 16px 16px;
  background-position: 0 0, 8px 8px;
  min-height: 40px;
}
/* ============================================================
   内容运营：置顶 / 分级 徽标 + 列表筛选条（migrations/018）
   实验室 / 课程 / 文档三类内容共用（首页与三个列表页）。
   ============================================================ */

/* 卡片左上角运营徽标：置顶（红）/ 精选（紫）/ 推荐（青） */
.card-badges { position: absolute; top: 10px; left: 10px; display: flex; gap: 6px; z-index: 2; }
.card-badge {
  font-size: 11px; line-height: 1; padding: 4px 8px; border-radius: 6px;
  color: #fff; font-weight: 600; letter-spacing: .3px;
  box-shadow: 0 2px 6px rgba(15, 23, 42, .18);
}
.card-badge.pin  { background: #dc2626; }
.card-badge.best { background: #7c3aed; }
.card-badge.reco { background: #0891b2; }
/* 置顶卡片加一圈浅红描边，列表里一眼可辨 */
.card.is-pinned { border-color: #fecaca; }

/* 列表页筛选条：上下两排 —— 第一排分类按钮，第二排排序/筛选维度 */
.filter-bar { display: flex; flex-direction: column; gap: 10px; margin-bottom: 22px; }
.filter-bar .filter-row { display: flex; gap: 10px; flex-wrap: wrap; align-items: center; }
.filter-bar .btn.active { background: var(--primary); color: #fff; border-color: var(--primary); }
.filter-bar .filter-label { font-size: 13px; color: var(--text-secondary); }

@media (max-width: 560px) {
  .card-badges { top: 8px; left: 8px; gap: 4px; }
  .card-badge { font-size: 10px; padding: 3px 6px; }
  .filter-bar { gap: 8px; margin-bottom: 16px; }
  .filter-bar .filter-row { gap: 8px; }
  .filter-bar .filter-label { width: 100%; }
}

/* ---------- lwMD 表格（GFM Markdown 表格语法，2026-10-20；2026-10-28 收敛到 .lwmd） ---------- */
.lwmd .md-table {
  border-collapse: collapse;
  margin: 8px 0 12px;
  max-width: 100%;
  font-size: 13.5px;
  line-height: 1.6;
}
.lwmd .md-table th,
.lwmd .md-table td {
  border: 1px solid var(--border);
  padding: 6px 12px;
  text-align: left;
}
.lwmd .md-table th {
  background: var(--bg);
  color: var(--text);
  font-weight: 600;
  white-space: nowrap;
}
.lwmd .md-table tbody tr:nth-child(even) { background: #f8fafc; }
.lwmd .md-table tbody tr:hover { background: #eef2ff; }
.lwmd .md-table td code { white-space: nowrap; }
/* 窄屏：宽表格横向滚动，避免撑破容器 */
@media (max-width: 560px) {
  .lwmd .md-table { display: block; overflow-x: auto; }
}

/* ---------- 首页 footer：ICP 备案列在窄屏恢复左对齐（2026-10-20） ---------- */
/* 桌面端右列 flex-direction:column + align-items:flex-end 让 ICP 与「文档」右缘对齐；
   ≤900px footer 变上下堆叠后仍右对齐会很怪，恢复左对齐 */
@media (max-width: 900px) {
  .footer-inner > div:last-child { align-items: flex-start; }
}

/* lwMD 引用块（> 与 | 两种写法；2026-10-28 收敛到 .lwmd 作用域） */
.lwmd blockquote {
  margin: 14px 0; padding: 10px 14px;
  border-left: 4px solid #f59e0b; background: #fffbeb;
  border-radius: 0 8px 8px 0; color: #92400e;
}
.lwmd blockquote p { margin: 4px 0; }

/* lwMD [TOC] 自动目录（2026-10-26）：mdh-N 标题锚点 + md-toc 目录框 */
.md-toc { margin: 14px 0; padding: 10px 16px; background: #f8fafc;
  border: 1px solid #e2e8f0; border-radius: 10px; font-size: 14px; }
.md-toc-title { font-weight: 700; color: #334155; margin-bottom: 6px; }
.md-toc a { color: #2563eb; text-decoration: none; }
.md-toc a:hover { text-decoration: underline; }
.md-toc-l1 { margin: 2px 0; font-weight: 600; }
.md-toc-l2 { margin: 2px 0 2px 16px; }
.md-toc-l3 { margin: 2px 0 2px 32px; }
.md-toc-l4 { margin: 2px 0 2px 48px; color: #64748b; }
h3[id], h4[id], h5[id], h6[id] { scroll-margin-top: 70px; }
/* ---------- lwMD 收敛说明（2026-10-28） ----------
   此处原来的 .doc-view / .md-body 补丁段已删除：lwMD 输出现在统一包 <div class="lwmd">，
   表格/引用块/代码块/标题/列表/分割线样式全部在上方 .lwmd 作用域一处维护。
   新增 Markdown 渲染特性时只写 .lwmd 选择器，不再按页面容器逐个补丁。 */

/* lwMD mermaid 图形（2026-10-28）：```mermaid 围栏先输出源码块，页面插入 DOM 后
   lwRenderMermaid() 懒加载 mermaid.js 并替换为 SVG。样式只写 .lwmd 作用域。 */
.lwmd .lwmd-mermaid {
  background: #fff;
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 12px;
  margin: 8px 0;
  overflow-x: auto;
  text-align: center;
}
.lwmd .lwmd-mermaid-svg svg { max-width: 100%; height: auto; }