/* ===== 苏州中小学知识点提纲 · 全局样式 ===== */
:root {
  --bg: #f4f6fb;
  --panel: #ffffff;
  --panel-2: #f8fafc;
  --text: #1f2430;
  --muted: #6b7280;
  --border: #e6e9f0;
  --accent: #3b82f6;
  --shadow: 0 1px 3px rgba(16, 24, 40, .06), 0 1px 2px rgba(16, 24, 40, .04);
  --shadow-lg: 0 10px 30px rgba(16, 24, 40, .10);
  --radius: 14px;
  --lv-basic: #64748b;
  --lv-key: #3b82f6;
  --lv-hard: #f59e0b;
  --lv-ext: #10b981;
}
body.dark {
  --bg: #0f141c;
  --panel: #171d29;
  --panel-2: #1c2331;
  --text: #e7eaf0;
  --muted: #98a2b3;
  --border: #2a3342;
  --shadow: 0 1px 3px rgba(0, 0, 0, .4);
  --shadow-lg: 0 10px 30px rgba(0, 0, 0, .5);
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  background: var(--bg);
  color: var(--text);
  font-size: 15px;
  line-height: 1.6;
}
a { color: inherit; text-decoration: none; }
button { font: inherit; cursor: pointer; }

/* ===== 顶部栏 ===== */
.topbar {
  position: sticky; top: 0; z-index: 50;
  display: flex; align-items: center; gap: 12px;
  padding: 10px 16px;
  background: var(--panel);
  border-bottom: 1px solid var(--border);
  box-shadow: var(--shadow);
}
.topbar .brand {
  display: flex; align-items: center; gap: 10px; font-weight: 700; font-size: 16px;
  white-space: nowrap;
}
.topbar .brand .dot {
  width: 12px; height: 12px; border-radius: 4px; flex: 0 0 auto;
}
.topbar .crumb { color: var(--muted); font-size: 13px; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.topbar .spacer { flex: 1; }
.topbar .search {
  display: flex; align-items: center; gap: 8px;
  background: var(--panel-2); border: 1px solid var(--border); border-radius: 999px;
  padding: 6px 14px; width: min(320px, 34vw);
}
.topbar .search input {
  border: 0; outline: 0; background: transparent; color: var(--text); width: 100%; font: inherit;
}
.icon-btn {
  border: 1px solid var(--border); background: var(--panel-2); color: var(--text);
  border-radius: 10px; width: 36px; height: 36px; display: inline-flex; align-items: center; justify-content: center;
}
.icon-btn:hover { border-color: var(--accent); color: var(--accent); }
.subject-select {
  background: var(--panel-2); border: 1px solid var(--border); color: var(--text);
  border-radius: 8px; padding: 6px 8px; font: inherit; font-size: 13px; max-width: 150px; outline: none;
}
.subject-select:focus { border-color: var(--accent); }

/* ===== 布局 ===== */
.layout { display: flex; min-height: calc(100vh - 57px); }
.sidebar {
  width: 264px; flex: 0 0 auto; background: var(--panel);
  border-right: 1px solid var(--border);
  overflow-y: auto; padding: 12px;
  position: sticky; top: 57px; height: calc(100vh - 57px);
}
.main { flex: 1; padding: 20px 24px 80px; max-width: 1000px; }
.sidebar-mask { display: none; }

/* ===== 侧边导航树 ===== */
.tree, .tree ul { list-style: none; margin: 0; padding: 0; }
.tree .node { display: flex; align-items: center; gap: 6px; padding: 5px 8px; border-radius: 8px; cursor: pointer; user-select: none; }
.tree .node:hover { background: var(--panel-2); }
.tree .node .caret { width: 14px; text-align: center; color: var(--muted); font-size: 11px; transition: transform .15s; }
.tree .node.open > .caret { transform: rotate(90deg); }
.tree .node.closed + .children { display: none; }
.tree .node .label { flex: 1; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.tree .node .cnt { color: var(--muted); font-size: 12px; }
.tree .node.unit:hover { color: var(--accent); }
.tree .node.active { background: rgba(59, 130, 246, .12); color: var(--accent); font-weight: 600; }
.tree .children { margin-left: 16px; border-left: 1px dashed var(--border); padding-left: 6px; }
.tree .hidden { display: none; }

/* ===== 统计条 ===== */
.stats {
  display: flex; flex-wrap: wrap; gap: 10px; margin-bottom: 16px;
}
.stat {
  background: var(--panel); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 10px 16px; box-shadow: var(--shadow); min-width: 96px;
}
.stat .num { font-size: 22px; font-weight: 700; }
.stat .lbl { color: var(--muted); font-size: 12px; }
.progress { height: 8px; background: var(--panel-2); border-radius: 99px; overflow: hidden; margin-top: 8px; }
.progress > i { display: block; height: 100%; background: linear-gradient(90deg, var(--accent), #8b5cf6); transition: width .3s; }

/* ===== 筛选 chips ===== */
.chips { display: flex; flex-wrap: wrap; gap: 8px; margin-bottom: 16px; }
.chip {
  border: 1px solid var(--border); background: var(--panel); color: var(--muted);
  padding: 5px 13px; border-radius: 999px; font-size: 13px;
}
.chip.on { color: #fff; border-color: transparent; }
.chip[data-lv="基础"].on { background: var(--lv-basic); }
.chip[data-lv="重点"].on { background: var(--lv-key); }
.chip[data-lv="难点"].on { background: var(--lv-hard); }
.chip[data-lv="拓展"].on { background: var(--lv-ext); }

/* ===== 单元区块 ===== */
.unit-block { margin-bottom: 28px; scroll-margin-top: 70px; }
.unit-head {
  display: flex; align-items: baseline; gap: 10px; margin: 0 0 12px;
  padding-bottom: 8px; border-bottom: 1px solid var(--border);
}
.unit-head h2 { font-size: 17px; margin: 0; }
.unit-head .sub { color: var(--muted); font-size: 13px; }
.grade-head {
  margin: 28px 0 16px; font-size: 14px; color: var(--muted);
  text-transform: none; letter-spacing: .5px;
}
.grade-head strong { color: var(--text); font-size: 18px; }

/* ===== 知识点卡片 ===== */
.cards { display: grid; grid-template-columns: 1fr; gap: 10px; }
.card {
  background: var(--panel); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 12px 14px; box-shadow: var(--shadow); position: relative;
  display: flex; gap: 12px; align-items: flex-start;
}
.card:hover { border-color: var(--accent); }
.card .fav {
  position: absolute; top: 8px; right: 8px; border: 0; background: transparent; font-size: 18px; line-height: 1;
  color: var(--muted); padding: 4px;
}
.card .fav.on { color: #f43f5e; }
.card .body { flex: 1; min-width: 0; padding-right: 20px; }
.card .pname { font-weight: 600; font-size: 15px; margin: 0 0 4px; }
.card .psummary { color: var(--muted); font-size: 13.5px; margin: 0; }
.badge {
  display: inline-block; font-size: 11px; padding: 1px 7px; border-radius: 6px; color: #fff; margin-right: 6px; vertical-align: 1px;
}
.badge.basic { background: var(--lv-basic); }
.badge.key { background: var(--lv-key); }
.badge.hard { background: var(--lv-hard); }
.badge.ext { background: var(--lv-ext); }
.tags { margin-top: 6px; display: flex; flex-wrap: wrap; gap: 5px; }
.tag { font-size: 11px; color: var(--muted); background: var(--panel-2); border: 1px solid var(--border); padding: 0 7px; border-radius: 5px; }

.empty { color: var(--muted); text-align: center; padding: 60px 0; }
.back-top { color: var(--muted); font-size: 13px; }

/* ===== 首页 ===== */
.home-hero { padding: 28px 4px 8px; }
.home-hero h1 { margin: 0 0 8px; font-size: 26px; }
.home-hero p { color: var(--muted); margin: 0; }
.stage-tabs { display: flex; gap: 8px; margin: 20px 0 18px; }
.stage-tab {
  border: 1px solid var(--border); background: var(--panel); color: var(--text);
  padding: 8px 22px; border-radius: 999px; font-weight: 600;
}
.stage-tab.on { background: var(--accent); color: #fff; border-color: transparent; }
.subject-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(230px, 1fr)); gap: 14px; }
.subject-card {
  background: var(--panel); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 16px; box-shadow: var(--shadow); display: flex; flex-direction: column; gap: 8px;
  transition: transform .12s, box-shadow .12s;
}
.subject-card:hover { transform: translateY(-2px); box-shadow: var(--shadow-lg); border-color: var(--accent); }
.subject-card .head { display: flex; align-items: center; gap: 10px; }
.subject-card .head .ic {
  width: 40px; height: 40px; border-radius: 11px; color: #fff; font-weight: 700; font-size: 18px;
  display: flex; align-items: center; justify-content: center; flex: 0 0 auto;
}
.subject-card .name { font-size: 17px; font-weight: 700; }
.subject-card .edition { color: var(--muted); font-size: 12px; }
.subject-card .meta { color: var(--muted); font-size: 12.5px; margin-top: auto; }

/* ===== 移动端 ===== */
.menu-btn { display: none; }
@media (max-width: 820px) {
  .sidebar {
    position: fixed; left: 0; top: 57px; bottom: 0; z-index: 60;
    transform: translateX(-100%); transition: transform .2s; height: auto; width: 280px;
    box-shadow: var(--shadow-lg);
  }
  .sidebar.open { transform: translateX(0); }
  .sidebar-mask { display: block; position: fixed; inset: 57px 0 0 0; background: rgba(0,0,0,.35); z-index: 55; }
  .menu-btn { display: inline-flex; }
  .subject-select { display: none; }
  .main { padding: 14px 14px 70px; }
  .topbar .crumb { display: none; }
  .topbar .search { width: auto; flex: 1; }
}

@media print {
  .topbar, .sidebar, .chips, .fav, .back-top, .sidebar-mask { display: none !important; }
  .main { max-width: 100%; padding: 0; }
  body { background: #fff; }
  .card { break-inside: avoid; box-shadow: none; }
}