:root {
  --primary: #1F4E79; --primary-2: #2D6CB5; --accent: #ED7D31;
  --bg: #F6F8FB; --card: #fff; --text: #22344A; --muted: #6B7C93; --line: #E3EAF3;
  --green: #2E8F63; --red: #C0392B; --soft: #EEF3FA;
}
* { margin: 0; padding: 0; box-sizing: border-box; -webkit-tap-highlight-color: transparent; }
body {
  font-family: -apple-system, "PingFang SC", "Microsoft YaHei", sans-serif;
  background: var(--bg); color: var(--text); line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}
a { color: inherit; text-decoration: none; }
.wrap { max-width: 900px; margin: 0 auto; padding: 0 16px 56px; }

/* ---------- 顶部 ---------- */
header.hero { background: linear-gradient(135deg, #1F4E79, #2D6CB5 60%, #3A7BC8); color: #fff; padding: 44px 16px 36px; text-align: center; }
header.hero .logo { font-size: 13px; letter-spacing: 4px; opacity: .8; margin-bottom: 8px; }
header.hero h1 { font-size: clamp(24px, 5.6vw, 36px); font-weight: 800; letter-spacing: 1px; }
header.hero .slogan { margin-top: 10px; font-size: clamp(14px, 3.4vw, 17px); opacity: .93; }
header.hero .slogan b { color: #FFD37A; }
header.hero .meta { display: inline-block; margin-top: 14px; font-size: 12.5px; background: rgba(255,255,255,.15); border-radius: 999px; padding: 5px 15px; }

/* ---------- 搜索 ---------- */
.searchbar { position: sticky; top: 0; z-index: 30; background: rgba(246,248,251,.94); backdrop-filter: blur(8px); padding: 12px 0 10px; border-bottom: 1px solid var(--line); }
.searchbar input { width: 100%; padding: 11px 16px; font-size: 15px; border: 1px solid var(--line); border-radius: 12px; background: #fff; outline: none; color: var(--text); }
.searchbar input:focus { border-color: var(--primary-2); box-shadow: 0 0 0 3px rgba(45,108,181,.12); }

/* ---------- 年级标签 ---------- */
.tabs { display: flex; gap: 8px; overflow-x: auto; padding: 16px 0 6px; scrollbar-width: none; }
.tabs::-webkit-scrollbar { display: none; }
.tab { flex: 0 0 auto; padding: 8px 16px; font-size: 14.5px; border-radius: 999px; border: 1px solid var(--line); background: #fff; color: var(--muted); cursor: pointer; white-space: nowrap; transition: .15s; }
.tab.on { background: var(--primary); border-color: var(--primary); color: #fff; font-weight: 700; }
.tab small { opacity: .7; font-size: 11.5px; margin-left: 4px; }

/* ---------- 章节分组 ---------- */
.vol-title { margin: 30px 0 4px; font-size: 19px; font-weight: 800; color: var(--primary); display: flex; align-items: center; gap: 10px; }
.vol-title span.dot { width: 6px; height: 20px; background: var(--accent); border-radius: 3px; display: inline-block; }
.chapter { margin: 22px 0 6px; }
.chapter h3 { font-size: 15.5px; color: var(--primary); font-weight: 700; padding-left: 12px; border-left: 3px solid var(--primary-2); margin-bottom: 10px; }
.chapter h3 small { color: var(--muted); font-weight: 400; font-size: 12.5px; margin-left: 6px; }

/* ---------- 知识点卡片 ---------- */
.kp-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(255px, 1fr)); gap: 10px; }
.kp-card { background: #fff; border: 1px solid var(--line); border-radius: 13px; padding: 13px 15px; transition: .16s; display: block; position: relative; }
.kp-card:hover { border-color: var(--primary-2); transform: translateY(-2px); box-shadow: 0 8px 20px rgba(31,78,121,.10); }
.kp-card .no { font-size: 11.5px; color: #9FB0C4; letter-spacing: .5px; }
.kp-card h4 { font-size: 15.5px; color: var(--text); font-weight: 700; margin: 2px 0 4px; }
.kp-card p { font-size: 13px; color: var(--muted); line-height: 1.6; display: -webkit-box; -webkit-line-clamp: 2; -webkit-box-orient: vertical; overflow: hidden; }
.flags { display: flex; flex-wrap: wrap; gap: 5px; margin: 3px 0 5px; }
.kp-card .badge { font-size: 10.5px; padding: 2px 7px; border-radius: 999px; background: #FDEEDF; color: #C05A10; font-weight: 700; white-space: nowrap; }
.kp-card .badge.fbk { background: #FDECEA; color: #B03A2E; border: 1px solid #F3C6C0; }
.kp-card .badge.fbk::before { content: "◆ "; font-size: 8px; }
.kp-card.fbk-card { box-shadow: inset 3px 0 0 #E4572E; }

/* ---------- 分班考标记（详情页） ---------- */
.fbk-strip { display: flex; flex-wrap: wrap; align-items: center; gap: 10px; margin-top: 14px; background: #FFF6F4; border: 1px solid #F6D5CF; border-left: 4px solid #E4572E; border-radius: 12px; padding: 11px 15px; font-size: 13.5px; color: #8C3A22; }
.fbk-strip .lb { font-weight: 800; color: #B03A2E; letter-spacing: .5px; }
.fbk-strip b { color: #B03A2E; font-variant-numeric: tabular-nums; }
.fbk-strip a { margin-left: auto; color: #B03A2E; font-weight: 700; white-space: nowrap; }

/* ---------- 分班考报告页 ---------- */
.stats { display: grid; grid-template-columns: repeat(auto-fit, minmax(120px, 1fr)); gap: 10px; margin-top: 18px; }
.stat { background: #fff; border: 1px solid var(--line); border-radius: 14px; padding: 14px 16px; text-align: center; }
.stat b { display: block; font-size: 26px; color: var(--primary); font-weight: 800; font-variant-numeric: tabular-nums; line-height: 1.2; }
.stat span { font-size: 12.5px; color: var(--muted); }
.rank { background: #fff; border: 1px solid var(--line); border-radius: 16px; overflow: hidden; margin-top: 16px; }
.rank .row { display: grid; grid-template-columns: 34px 1fr 74px; gap: 10px; align-items: center; padding: 11px 14px; border-top: 1px solid var(--line); }
.rank .row:first-child { border-top: none; background: var(--soft); font-size: 12.5px; color: var(--muted); font-weight: 700; }
.rank .row .rk { font-size: 13px; color: #A8B6C8; font-weight: 800; text-align: center; font-variant-numeric: tabular-nums; }
.rank .row .tt { font-size: 14.5px; font-weight: 700; color: var(--text); }
.rank .row .tt small { display: block; font-size: 11.5px; color: var(--muted); font-weight: 400; margin-top: 1px; }
.rank .row .barwrap { height: 7px; background: #EEF2F7; border-radius: 4px; margin-top: 6px; overflow: hidden; }
.rank .row .bar { height: 100%; border-radius: 4px; background: linear-gradient(90deg, #2D6CB5, #4E96DE); }
.rank .row.hot .bar { background: linear-gradient(90deg, #E4572E, #F09055); }
.rank .row .num { text-align: right; font-size: 12.5px; color: var(--muted); font-variant-numeric: tabular-nums; }
.rank .row .num b { display: block; font-size: 15px; color: var(--primary); }
.lv { display: inline-block; font-size: 10.5px; padding: 1px 6px; border-radius: 999px; margin-left: 6px; vertical-align: 1px; font-weight: 700; }
.lv.高频 { background: #FDECEA; color: #B03A2E; }
.lv.中频 { background: #FDF1E3; color: #B06A12; }
.lv.低频 { background: #EDF2F8; color: #5B6B80; }
.volbars { background: #fff; border: 1px solid var(--line); border-radius: 16px; padding: 16px 18px; margin-top: 16px; }
.volbar { display: grid; grid-template-columns: 54px 1fr 42px; gap: 10px; align-items: center; margin: 7px 0; font-size: 13px; }
.volbar .vb { height: 16px; border-radius: 4px; background: linear-gradient(90deg, #2D6CB5, #7FB2E5); min-width: 4px; }
.volbar .vn { text-align: right; color: var(--muted); font-variant-numeric: tabular-nums; }
.volbar.on .vb { background: linear-gradient(90deg, #E4572E, #F4A26B); }
.note { font-size: 13px; color: var(--muted); margin-top: 8px; }

/* ---------- 知识点详情页 ---------- */
.topbar { background: #fff; border-bottom: 1px solid var(--line); position: sticky; top: 0; z-index: 40; }
.topbar .inner { max-width: 900px; margin: 0 auto; padding: 11px 16px; display: flex; align-items: center; gap: 12px; }
.topbar a.back { font-size: 14px; color: var(--muted); }
.topbar a.back:hover { color: var(--primary); }
.topbar .crumb { font-size: 12.5px; color: #9FB0C4; margin-left: auto; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }

.kp-head { padding: 26px 0 6px; }
.kp-head .tagline { font-size: 12.5px; color: var(--accent); font-weight: 700; letter-spacing: 1px; }
.kp-head h1 { font-size: clamp(24px, 5.5vw, 31px); color: var(--primary); font-weight: 800; margin: 6px 0 10px; line-height: 1.35; }
.kp-head .essence { font-size: 16px; color: var(--text); background: linear-gradient(180deg, transparent 62%, #FFF0D9 62%); display: inline; }

.block { background: #fff; border: 1px solid var(--line); border-radius: 16px; padding: 20px 22px; margin-top: 16px; }
.block > h2 { font-size: 16px; color: var(--primary); font-weight: 800; margin-bottom: 12px; display: flex; align-items: center; gap: 8px; }
.block > h2::before { content: ""; width: 4px; height: 16px; background: var(--accent); border-radius: 2px; }
.block ul.pts { list-style: none; }
.block ul.pts li { position: relative; padding-left: 22px; margin: 9px 0; font-size: 15px; }
.block ul.pts li::before { content: ""; position: absolute; left: 4px; top: 10px; width: 7px; height: 7px; border-radius: 50%; background: var(--primary-2); }
.block ul.pts li b { color: var(--primary); }

.formula { background: var(--soft); border-radius: 12px; padding: 16px 18px; text-align: center; font-size: 18px; color: var(--primary); font-weight: 700; letter-spacing: .5px; line-height: 1.9; word-break: break-word; }
.formula small { display: block; font-size: 12.5px; color: var(--muted); font-weight: 400; margin-top: 6px; letter-spacing: 0; }

.ex-q { font-size: 15px; margin-bottom: 12px; }
.ex-q b { color: var(--accent); }
.btn { display: inline-block; padding: 9px 20px; font-size: 14px; border-radius: 10px; border: 1px solid var(--primary-2); color: var(--primary-2); background: #fff; cursor: pointer; font-weight: 700; transition: .15s; }
.btn:hover { background: var(--soft); }
.btn.solid { background: var(--primary); border-color: var(--primary); color: #fff; }
.btn.solid:hover { background: var(--primary-2); }
.ex-a { display: none; margin-top: 14px; padding-top: 14px; border-top: 1px dashed var(--line); }
.ex-a.on { display: block; animation: fade .28s ease; }
.ex-a ol { margin-left: 20px; }
.ex-a li { font-size: 14.5px; margin: 7px 0; color: var(--text); }
.ex-a .ans { margin-top: 10px; font-size: 15px; font-weight: 700; color: var(--green); background: #EAF6F0; padding: 9px 14px; border-radius: 9px; }
@keyframes fade { from { opacity: 0; transform: translateY(4px); } to { opacity: 1; transform: none; } }

.trap { border-left: 4px solid var(--accent); background: #FFF8F1; }
.trap h2::before { background: var(--accent); }
.trap p { font-size: 14.7px; }
.trap p b { color: #C05A10; }

.keynote { background: linear-gradient(135deg, #1F4E79, #2D6CB5); color: #fff; border: none; }
.keynote h2 { color: #fff; }
.keynote h2::before { background: #FFD37A; }
.keynote p { font-size: 16px; line-height: 1.9; }

.pager { display: flex; gap: 12px; margin-top: 24px; }
.pager a { flex: 1; background: #fff; border: 1px solid var(--line); border-radius: 13px; padding: 14px 16px; font-size: 14px; transition: .15s; }
.pager a:hover { border-color: var(--primary-2); }
.pager a span { display: block; font-size: 11.5px; color: #9FB0C4; margin-bottom: 3px; }
.pager a b { color: var(--primary); font-size: 14.5px; }
.pager a.next { text-align: right; }

/* ---------- 可视化舞台 ---------- */
.viz { background: #fff; border: 1px solid var(--line); border-radius: 16px; padding: 16px; margin-top: 16px; }
.viz .viz-head { display: flex; align-items: baseline; gap: 10px; margin-bottom: 10px; }
.viz .viz-head h2 { font-size: 16px; color: var(--primary); font-weight: 800; }
.viz .viz-head span { font-size: 12px; color: var(--muted); }
.viz svg { display: block; width: 100%; height: auto; overflow: visible; }
.viz .ctrl { display: flex; flex-wrap: wrap; gap: 10px 16px; align-items: center; margin-top: 12px; padding-top: 12px; border-top: 1px dashed var(--line); font-size: 13.5px; color: var(--muted); }
.viz .ctrl label { display: flex; align-items: center; gap: 8px; }
.viz .ctrl input[type=range] { width: 110px; accent-color: var(--primary-2); }
.viz .ctrl .val { color: var(--accent); font-weight: 800; font-variant-numeric: tabular-nums; min-width: 34px; display: inline-block; }
.viz .readout { margin-top: 12px; background: var(--soft); border-radius: 10px; padding: 10px 14px; font-size: 14.5px; color: var(--primary); font-weight: 700; text-align: center; }
.viz .seg { display: inline-flex; border: 1px solid var(--line); border-radius: 9px; overflow: hidden; }
.viz .seg button { padding: 6px 13px; font-size: 13px; border: none; background: #fff; color: var(--muted); cursor: pointer; }
.viz .seg button.on { background: var(--primary); color: #fff; font-weight: 700; }
.viz text { font-family: -apple-system, "PingFang SC", "Microsoft YaHei", sans-serif; }
.viz .mini-note { margin-top: 10px; font-size: 12.5px; color: var(--muted); }

/* ---------- 其他 ---------- */
.empty { text-align: center; color: var(--muted); font-size: 14.5px; padding: 40px 0; }
footer { text-align: center; margin-top: 44px; font-size: 12.5px; color: #A8B6C8; line-height: 2; }
footer .brand { font-weight: 700; color: var(--primary); letter-spacing: 1px; }

@media (max-width: 480px) {
  .block { padding: 17px 16px; border-radius: 14px; }
  .kp-grid { grid-template-columns: 1fr; }
  .viz { padding: 13px; }
}

/* ---------- 真题库横条 ---------- */
.pp-strip { display: flex; flex-wrap: wrap; align-items: center; gap: 10px; margin-top: 10px; background: #F2F7FF; border: 1px solid #D3E2F7; border-left: 4px solid #2D6CB5; border-radius: 12px; padding: 11px 15px; font-size: 13.5px; color: #22456E; }
.pp-strip .lb { font-weight: 800; color: #1F4E79; letter-spacing: .5px; }
.pp-strip b { color: #1F4E79; font-variant-numeric: tabular-nums; }
.pp-strip .go { margin-left: auto; color: #1F4E79; font-weight: 700; white-space: nowrap; }

/* 中考真题标记条 */
.zk-strip { background: #EFF5FC; border-color: #C9DCF3; }
.zk-strip .lb { background: #1F4E79; }
.zk-strip a { margin-left: auto; }

/* ===== 名师视频课 ===== */
.vid-strip { background: #F5F0FF; border-color: #DCCDF5; border-left-color: #6B46C1; color: #44337A; }
.vid-strip .lb { color: #553C9A; }
.vid-strip b { color: #553C9A; font-variant-numeric: tabular-nums; }
.vid-strip .go { margin-left: auto; color: #553C9A; font-weight: 700; white-space: nowrap; }

/* 知识点页视频讲解区块 */
.vidblock video { width: 100%; max-height: 430px; border-radius: 10px; background: #000; display: block; }
.vid-list { display: flex; flex-direction: column; gap: 6px; margin-top: 10px; max-height: 260px; overflow-y: auto; }
.vid-item { display: flex; align-items: center; gap: 8px; padding: 9px 12px; border-radius: 9px; border: 1px solid #E3E8F0; background: #FAFBFD; cursor: pointer; font-size: 13.5px; color: #2C3E50; line-height: 1.45; }
.vid-item:hover { border-color: #6B46C1; background: #F7F3FF; }
.vid-item.on { border-color: #6B46C1; background: #F1EAFD; font-weight: 700; color: #44337A; }
.vid-item .ext { flex: none; font-size: 11px; font-weight: 700; color: #7C5CBF; background: #EDE6FA; border-radius: 6px; padding: 1px 7px; }
.vid-item::before { content: "▶"; flex: none; font-size: 11px; color: #6B46C1; }
.vid-note { margin-top: 8px; font-size: 12.5px; color: #7A8494; }

/* 视频课页面 */
.vidlib-player video { width: 100%; max-height: 62vh; border-radius: 12px; background: #000; display: block; }
.vidlib-now { margin-top: 10px; font-size: 15px; font-weight: 700; color: #22303F; }
.vidlib-meta { margin-top: 2px; font-size: 12.5px; color: #7A8494; }
.vidlib-tools { display: flex; flex-wrap: wrap; gap: 10px; margin: 16px 0 6px; align-items: center; }
.vidlib-tools input { flex: 1; min-width: 200px; }
.vidlib-tabs { display: flex; gap: 8px; flex-wrap: wrap; }
.vidlib-tabs a { padding: 6px 14px; border-radius: 999px; border: 1px solid #D7DEE9; font-size: 13px; color: #44546A; cursor: pointer; background: #fff; }
.vidlib-tabs a.on { background: #553C9A; border-color: #553C9A; color: #fff; font-weight: 700; }
.vlib-ch { margin-top: 20px; }
.vlib-ch h3 { display: flex; align-items: baseline; gap: 8px; margin: 0 0 10px; }
.vlib-ch h3 small { font-weight: 400; color: #8A94A6; }
.vlib-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(230px, 1fr)); gap: 10px; }
.vlib-item { display: flex; gap: 9px; align-items: flex-start; padding: 10px 12px; border: 1px solid #E3E8F0; border-radius: 10px; background: #fff; cursor: pointer; font-size: 13px; line-height: 1.5; color: #2C3E50; text-align: left; }
.vlib-item:hover { border-color: #6B46C1; background: #F9F6FF; }
.vlib-item.on { border-color: #6B46C1; background: #F1EAFD; font-weight: 700; }
.vlib-item .no { flex: none; width: 26px; height: 26px; border-radius: 8px; background: #EFEAF8; color: #6B46C1; font-size: 12px; font-weight: 800; display: flex; align-items: center; justify-content: center; margin-top: 1px; }
.vlib-empty { padding: 40px 0; text-align: center; color: #8A94A6; }