/* 数学知识地图 · 设计系统
   纸感底 / 墨绿主色 / 宋体标题 / 克制的阴影 */

:root {
  --paper: #faf8f4;
  --paper-2: #f4f0e8;
  --surface: #fffefb;
  --surface-2: #f7f4ed;
  --ink: #1f1d19;
  --ink-2: #57524a;
  --ink-3: #7e776a;
  --line: #e7e1d6;
  --line-2: #f0ebe2;
  --line-strong: #d9d1c3;

  --sage: #2f6b5e;
  --sage-deep: #24544a;
  --sage-soft: #e9f1ed;
  --sage-line: #c9ded4;

  --clay: #b25f3f;
  --clay-soft: #f9ebe4;
  --clay-line: #e4c4b5;

  --junior: #4f6ea8;
  --junior-soft: #ecf0f8;
  --junior-line: #c8d4ea;

  --primary: #5c8f76;
  --primary-soft: #ecf3ef;
  --primary-line: #cfe0d5;

  --gold: #9a7f45;
  --gold-soft: #f7f1e3;

  --ok: #2f6b5e;
  --ok-soft: #e9f1ed;
  --warn: #9a6a1f;
  --warn-soft: #fbf2df;
  --bad: #a8452f;
  --bad-soft: #f9e9e3;

  --r-lg: 20px;
  --r-md: 14px;
  --r-sm: 10px;
  --shadow-1: 0 1px 2px rgba(31, 29, 25, .04), 0 8px 24px -18px rgba(31, 29, 25, .25);
  --shadow-2: 0 2px 4px rgba(31, 29, 25, .05), 0 18px 40px -24px rgba(31, 29, 25, .35);

  --serif: "Songti SC", "Noto Serif SC", "Source Han Serif SC", "STSong", serif;
  --sans: "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans SC", system-ui, sans-serif;
  --mono: "SF Mono", "JetBrains Mono", Menlo, monospace;

  --max: 1160px;
  --header-h: 64px;
}

*, *::before, *::after { box-sizing: border-box; }
[hidden] { display: none !important; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }
body {
  margin: 0;
  display: flex;
  flex-direction: column;
  min-height: 100vh;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 16px;
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
}
main { flex: 1 0 auto; }
::selection { background: #dcebe4; }
a { color: inherit; text-decoration: none; }
button { font: inherit; color: inherit; }
img, svg { display: block; max-width: 100%; }
:focus-visible { outline: 2px solid var(--sage); outline-offset: 3px; border-radius: 4px; }

.serif { font-family: var(--serif); font-weight: 600; }
.wrap { width: min(var(--max), 100%); margin: 0 auto; padding: 0 24px; }
.muted { color: var(--ink-2); }
.small { font-size: 13.5px; color: var(--ink-3); }
.mono { font-family: var(--mono); font-size: 12.5px; }

/* ---------------- header ---------------- */
.site-header {
  flex: none;
  position: sticky; top: 0; z-index: 40;
  height: var(--header-h);
  background: rgba(250, 248, 244, .88);
  backdrop-filter: saturate(180%) blur(12px);
  -webkit-backdrop-filter: saturate(180%) blur(12px);
  border-bottom: 1px solid var(--line);
}
.site-header .wrap { height: 100%; display: flex; align-items: center; gap: 28px; }
.brand { display: flex; align-items: center; gap: 10px; font-weight: 700; letter-spacing: .01em; flex: none; }
.brand .mark { width: 32px; height: 32px; display: flex; align-items: center; justify-content: center; flex: none; }
/* 原图四周为透明留白，放大画布以保持标志本体约 32px。 */
.brand .mark img { width: 43px; height: 43px; max-width: none; flex: none; }
.brand b { font-family: var(--serif); font-size: 18px; font-weight: 600; white-space: nowrap; }
.brand-sub { font-size: 13px; color: var(--ink-3); font-weight: 500; white-space: nowrap; letter-spacing: .01em; }
@media (max-width: 980px) { .brand-sub { display: none; } }
.nav { display: flex; align-items: center; gap: 4px; margin-left: 6px; }
.nav a {
  padding: 7px 12px; border-radius: 999px; font-size: 14.5px; color: var(--ink-2);
  transition: background .16s, color .16s;
}
.nav a:hover { background: var(--paper-2); color: var(--ink); }
.nav a.on { background: var(--sage-soft); color: var(--sage-deep); font-weight: 600; }
.header-right { margin-left: auto; display: flex; align-items: center; gap: 10px; }

.search-trigger {
  display: inline-flex; align-items: center; gap: 8px;
  height: 36px; padding: 0 10px 0 12px; border-radius: 999px;
  background: var(--surface); border: 1px solid var(--line);
  color: var(--ink-3); font-size: 13.5px; cursor: pointer;
  transition: border-color .16s, color .16s;
}
.search-trigger:hover { border-color: var(--line-strong); color: var(--ink-2); }
.search-trigger kbd {
  font-family: var(--mono); font-size: 11px; padding: 1px 5px; border-radius: 5px;
  background: var(--paper-2); border: 1px solid var(--line); color: var(--ink-3);
}
@media (max-width: 900px) { .search-trigger span, .search-trigger kbd { display: none; } .search-trigger { width: 36px; justify-content: center; padding: 0; } }

/* ---------------- buttons ---------------- */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  height: 44px; padding: 0 20px; border-radius: 999px;
  border: 1px solid transparent; background: var(--sage); color: #fff;
  font-size: 15px; font-weight: 600; cursor: pointer;
  transition: transform .14s, background .16s, border-color .16s, color .16s;
}
.btn:hover { background: var(--sage-deep); }
.btn:active { transform: translateY(1px); }
.btn.ghost { background: transparent; border-color: var(--line-strong); color: var(--ink); }
.btn.ghost:hover { background: var(--surface); border-color: var(--ink-3); }
.btn.small { height: 36px; padding: 0 14px; font-size: 13.5px; }
.btn.wide { width: 100%; }
.btn:disabled { opacity: .45; cursor: not-allowed; }

.chip {
  display: inline-flex; align-items: center; gap: 6px;
  height: 32px; padding: 0 13px; border-radius: 999px;
  background: var(--surface); border: 1px solid var(--line);
  font-size: 13.5px; color: var(--ink-2); cursor: pointer; white-space: nowrap;
  transition: all .15s;
}
.chip:hover { border-color: var(--line-strong); color: var(--ink); }
.chip.on { background: var(--sage); border-color: var(--sage); color: #fff; }
.chip.soft.on { background: var(--sage-soft); border-color: var(--sage-line); color: var(--sage-deep); }
.chips { display: flex; flex-wrap: wrap; gap: 8px; }

.tag {
  display: inline-flex; align-items: center; gap: 5px;
  padding: 2px 9px; border-radius: 999px; font-size: 12px; line-height: 1.7;
  background: var(--surface-2); color: var(--ink-2); white-space: nowrap;
}
.tag.primary { background: var(--primary-soft); color: #3f6f58; }
.tag.junior { background: var(--junior-soft); color: #3f5c92; }
.tag.clay { background: var(--clay-soft); color: var(--clay); }
.tag.sage { background: var(--sage-soft); color: var(--sage-deep); }

/* ---------------- home ---------------- */
.hero { padding: 56px 0 40px; }
.hero-grid { display: grid; grid-template-columns: minmax(0, 1.15fr) minmax(0, .85fr); gap: 48px; align-items: center; }
.eyebrow {
  display: inline-flex; align-items: center; gap: 10px;
  font-size: 12px; letter-spacing: .16em; color: var(--sage); font-weight: 600;
  margin: 0 0 18px;
}
.eyebrow::before { content: ""; width: 24px; height: 1px; background: var(--sage); }
h1.display {
  font-family: var(--serif); font-weight: 600;
  font-size: clamp(34px, 5vw, 56px); line-height: 1.16; letter-spacing: .005em;
  margin: 0 0 20px;
}
.hero-line { display: block; }
h1.display em { font-style: normal; color: var(--sage); position: relative; white-space: nowrap; }
h1.display em::after {
  content: ""; position: absolute; left: 0; right: 0; bottom: .06em; height: .28em;
  background: var(--sage-soft); z-index: -1; border-radius: 2px;
}
.lede { font-size: 17px; line-height: 1.8; color: var(--ink-2); max-width: 34em; margin: 0 0 26px; }
.hero-actions { display: flex; flex-wrap: wrap; gap: 10px; margin-bottom: 18px; }
.hero-note { font-size: 13px; color: var(--ink-3); margin-bottom: 6px; }
.hero-note a { color: var(--sage); font-weight: 600; border-bottom: 1px solid var(--sage-line); }
.hero-note a:hover { border-bottom-color: var(--sage); }

.hero-art {
  background: var(--surface); border: 1px solid var(--line); border-radius: var(--r-lg);
  padding: 18px; box-shadow: var(--shadow-1);
}
.hero-art .art-head { display: flex; align-items: center; justify-content: space-between; margin-bottom: 12px; }
.hero-art .art-head span { font-size: 11.5px; letter-spacing: .1em; color: var(--ink-3); }

.stat-strip {
  display: grid; grid-template-columns: repeat(4, 1fr);
  border-top: 1px solid var(--line); border-bottom: 1px solid var(--line);
  margin-top: 8px;
}
.stat-strip div { padding: 20px 8px; text-align: center; border-left: 1px solid var(--line-2); }
.stat-strip div:first-child { border-left: 0; }
.stat-strip b { display: block; font-family: var(--serif); font-size: 28px; font-weight: 600; line-height: 1.2; }
.stat-strip span { font-size: 12.5px; color: var(--ink-3); }

.section { padding: 56px 0; border-top: 1px solid var(--line); }
.section-head { display: flex; align-items: flex-end; justify-content: space-between; gap: 20px; margin-bottom: 26px; }
.section-head h2 { font-family: var(--serif); font-size: 27px; font-weight: 600; margin: 0; line-height: 1.4; }
.section-head p { margin: 6px 0 0; color: var(--ink-3); font-size: 14px; }
.section-head .more { font-size: 13.5px; color: var(--sage); font-weight: 600; white-space: nowrap; }

.steps { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; }
.step-card {
  position: relative; background: var(--surface); border: 1px solid var(--line);
  border-radius: var(--r-lg); padding: 22px 22px 20px;
}
.step-card .n {
  font-family: var(--mono); font-size: 11px; letter-spacing: .12em; color: var(--sage);
  display: inline-flex; align-items: center; gap: 8px; margin-bottom: 12px;
}
.step-card .n::after { content: ""; flex: 1; height: 1px; background: var(--line); }
.step-card h3 { margin: 0 0 6px; font-size: 17px; font-weight: 600; }
.step-card p { margin: 0; font-size: 14px; color: var(--ink-2); line-height: 1.7; }

.grade-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 12px; }
.grade-card {
  display: flex; align-items: center; gap: 14px;
  padding: 16px 18px; background: var(--surface); border: 1px solid var(--line);
  border-radius: var(--r-md); transition: border-color .16s, transform .16s, box-shadow .16s;
}
.grade-card:hover { border-color: var(--line-strong); transform: translateY(-2px); box-shadow: var(--shadow-1); }
.grade-card .num {
  width: 42px; height: 42px; border-radius: 12px; flex: none;
  display: grid; place-items: center; font-family: var(--serif); font-size: 19px;
  background: var(--primary-soft); color: #3f6f58;
}
.grade-card.junior .num { background: var(--junior-soft); color: #3f5c92; }
.grade-card .body { min-width: 0; }
.grade-card strong { display: block; font-size: 15px; font-weight: 600; }
.grade-card span { font-size: 12.5px; color: var(--ink-3); }

.return-card {
  display: flex; align-items: center; gap: 18px;
  padding: 18px 22px; border-radius: var(--r-lg);
  background: linear-gradient(100deg, var(--sage-soft), rgba(233, 241, 237, 0));
  border: 1px solid var(--sage-line);
}
.return-card .body { flex: 1; min-width: 0; }
.return-card b { display: block; font-size: 15px; }
.return-card span { font-size: 13px; color: var(--ink-2); }

/* ---------------- footer ---------------- */

/* ---------------- map ---------------- */
.map-shell {
  display: grid; grid-template-columns: 300px minmax(0, 1fr) 336px;
  height: calc(100vh - var(--header-h));
  min-height: 560px;
}
.sidebar { border-right: 1px solid var(--line); display: flex; flex-direction: column; min-height: 0; background: var(--paper); }
.sidebar-top { padding: 16px 16px 12px; border-bottom: 1px solid var(--line-2); }
.search-box { position: relative; }
.search-box input {
  width: 100%; height: 40px; padding: 0 12px 0 34px;
  border: 1px solid var(--line); border-radius: var(--r-sm);
  background: var(--surface); font-size: 14px; color: var(--ink);
}
.search-box input::placeholder { color: var(--ink-3); }
.search-box svg { position: absolute; left: 11px; top: 50%; transform: translateY(-50%); color: var(--ink-3); }
.filters { display: flex; flex-wrap: wrap; gap: 6px; margin-top: 10px; }
.filters .chip { height: 28px; padding: 0 10px; font-size: 12.5px; }
.list { overflow-y: auto; flex: 1; padding: 6px 8px 40px; }
.sidebar-foot { flex: none; padding: 9px 16px; border-top: 1px solid var(--line-2); font-size: 11.5px; color: var(--ink-3); }
.sidebar-foot a { border-bottom: 1px solid var(--line); }
.list-meta { display: flex; justify-content: space-between; padding: 10px 8px 6px; font-size: 12px; color: var(--ink-3); }
.group { margin-bottom: 2px; }
.group > summary {
  list-style: none; cursor: pointer; padding: 9px 10px; border-radius: 8px;
  display: flex; align-items: center; gap: 8px; font-size: 13px; color: var(--ink-2);
}
.group > summary::-webkit-details-marker { display: none; }
.group > summary:hover { background: var(--paper-2); }
.group > summary .count { margin-left: auto; font-size: 11.5px; color: var(--ink-3); font-family: var(--mono); }
.group[open] > summary { color: var(--ink); font-weight: 600; }
.list-item {
  display: block; padding: 9px 10px 9px 18px; border-radius: 8px;
  font-size: 13.5px; color: var(--ink-2); cursor: pointer; line-height: 1.5;
  position: relative; border-left: 2px solid transparent;
}
.list-item:hover { background: var(--paper-2); color: var(--ink); }
.list-item.on { background: var(--sage-soft); color: var(--sage-deep); font-weight: 600; border-left-color: var(--sage); }
.list-item .dot { display: inline-block; width: 6px; height: 6px; border-radius: 50%; margin-right: 7px; vertical-align: 2px; }
.list-item .dot.p { background: var(--primary); }
.list-item .dot.j { background: var(--junior); }

.graph-pane { position: relative; min-width: 0; background: var(--paper); display: flex; flex-direction: column; }
.graph-toolbar {
  display: flex; align-items: center; gap: 8px; padding: 12px 16px;
  border-bottom: 1px solid var(--line-2); flex-wrap: wrap;
}
.seg { display: inline-flex; background: var(--surface); border: 1px solid var(--line); border-radius: 999px; padding: 2px; }
.seg button {
  border: 0; background: transparent; height: 28px; padding: 0 11px; border-radius: 999px;
  font-size: 12.5px; color: var(--ink-2); cursor: pointer;
}
.seg button.on { background: var(--sage); color: #fff; }
.toolbar-label { font-size: 12px; color: var(--ink-3); margin-right: 2px; }
.graph-tools { margin-left: auto; display: flex; gap: 4px; }
.icon-btn {
  width: 32px; height: 32px; border-radius: 8px; border: 1px solid var(--line);
  background: var(--surface); display: grid; place-items: center; cursor: pointer; color: var(--ink-2);
}
.icon-btn:hover { border-color: var(--line-strong); color: var(--ink); }
.graph-stage { position: relative; flex: 1; overflow: hidden; }
.graph-stage svg { width: 100%; height: 100%; cursor: grab; touch-action: none; }
.graph-stage svg.dragging { cursor: grabbing; }
.graph-empty {
  position: absolute; inset: 0; display: grid; place-items: center; text-align: center; padding: 30px;
}
.graph-empty .inner { max-width: 360px; }
.graph-empty h3 { font-family: var(--serif); font-size: 20px; margin: 0 0 8px; }
.graph-empty p { color: var(--ink-2); font-size: 14px; margin: 0 0 16px; }
.legend { display: flex; flex-wrap: wrap; gap: 14px; padding: 10px 16px 12px; font-size: 12px; color: var(--ink-3); border-top: 1px solid var(--line-2); }
.legend i { display: inline-block; width: 10px; height: 10px; border-radius: 3px; margin-right: 5px; vertical-align: -1px; }
.legend .line { width: 16px; height: 0; border-top: 1.5px solid var(--ink-3); vertical-align: 3px; }
.legend .line.dash { border-top-style: dashed; }

.detail { border-left: 1px solid var(--line); background: var(--surface); overflow-y: auto; }
.detail-inner { padding: 20px 22px 40px; }
.detail h2 { font-family: var(--serif); font-size: 22px; font-weight: 600; line-height: 1.4; margin: 0 0 8px; }
.meta-row { display: flex; flex-wrap: wrap; gap: 6px; margin-bottom: 16px; }
.detail h4 { font-size: 12px; letter-spacing: .1em; color: var(--ink-3); font-weight: 600; margin: 22px 0 8px; }
.detail p { margin: 0 0 10px; font-size: 14px; color: var(--ink-2); line-height: 1.75; }
.criteria { margin: 0; padding-left: 18px; font-size: 14px; color: var(--ink-2); }
.criteria li { margin-bottom: 4px; }
.rel { display: flex; flex-direction: column; gap: 2px; }
.rel a { display: flex; align-items: flex-start; gap: 8px; padding: 7px 8px; margin: 0 -8px; border-radius: 8px; font-size: 13.5px; color: var(--ink-2); }
.rel a:hover { background: var(--surface-2); color: var(--ink); }
.rel .badge { flex: none; font-size: 10.5px; padding: 1px 6px; border-radius: 4px; margin-top: 2px; }
.rel .badge.hard { background: var(--clay-soft); color: var(--clay); }
.rel .badge.soft { background: var(--surface-2); color: var(--ink-3); }
.detail-actions { display: grid; gap: 8px; margin-top: 24px; }

/* ---------------- topic ---------------- */
.topic-head { padding: 28px 0 26px; border-bottom: 1px solid var(--line); }
.crumb { display: flex; flex-wrap: wrap; align-items: center; gap: 6px; font-size: 12.5px; color: var(--ink-3); margin-bottom: 14px; }
.crumb a:hover { color: var(--sage); }
.crumb .sep { color: var(--line-strong); }
.topic-title { font-family: var(--serif); font-size: clamp(28px, 4vw, 40px); font-weight: 600; line-height: 1.3; margin: 0 0 12px; }
.topic-layout { display: grid; grid-template-columns: minmax(0, 1fr) 320px; gap: 48px; padding: 36px 0 64px; align-items: start; }
.prose h2 { font-family: var(--serif); font-size: 22px; font-weight: 600; margin: 34px 0 12px; }
.prose h2:first-child { margin-top: 0; }
.prose p { margin: 0 0 14px; color: var(--ink-2); }
.lead-quote {
  font-family: var(--serif); font-size: 20px; line-height: 1.7; color: var(--ink);
  padding: 4px 0 4px 20px; border-left: 2px solid var(--sage); margin: 0 0 24px;
}
.checklist { list-style: none; margin: 0; padding: 0; display: grid; gap: 10px; }
.checklist li { display: flex; gap: 10px; font-size: 15px; color: var(--ink-2); }
.checklist li::before {
  content: ""; width: 18px; height: 18px; border-radius: 50%; flex: none; margin-top: 3px;
  background: var(--sage-soft) url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 16 16'%3E%3Cpath d='M4 8.5l2.5 2.5L12 5.5' fill='none' stroke='%232f6b5e' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'/%3E%3C/svg%3E") center/13px no-repeat;
}
.aside-card { background: var(--surface); border: 1px solid var(--line); border-radius: var(--r-md); padding: 18px; margin-bottom: 14px; }
.aside-card h3 { font-size: 12px; letter-spacing: .1em; color: var(--ink-3); font-weight: 600; margin: 0 0 10px; }
.aside-card .path-item { display: flex; gap: 10px; padding: 7px 0; font-size: 13.5px; color: var(--ink-2); border-bottom: 1px dashed var(--line-2); }
.aside-card .path-item:last-child { border-bottom: 0; }
.aside-card .path-item .g { flex: none; width: 38px; font-size: 11px; color: var(--ink-3); font-family: var(--mono); }
.aside-card .path-item a:hover { color: var(--sage); }
.empty-note { font-size: 13px; color: var(--ink-3); margin: 0; }

/* 题目 */
.qa { border: 1px solid var(--line); border-radius: var(--r-md); background: var(--surface); padding: 18px 20px; margin-bottom: 12px; }
.qa .qhead { display: flex; align-items: center; gap: 8px; margin-bottom: 10px; font-size: 11.5px; color: var(--ink-3); letter-spacing: .06em; }
.qa .qhead .d { margin-left: auto; font-family: var(--mono); }
.qa .stem { font-size: 15.5px; line-height: 1.8; margin-bottom: 12px; white-space: pre-wrap; }
.qa .opts { display: grid; gap: 8px; margin-bottom: 12px; }
.qa .opt { display: flex; gap: 10px; font-size: 14px; color: var(--ink-2); }
.qa .opt b { flex: none; width: 20px; height: 20px; border-radius: 6px; background: var(--surface-2); display: grid; place-items: center; font-size: 11px; font-weight: 600; }
.qa details summary { cursor: pointer; font-size: 13px; color: var(--sage); font-weight: 600; list-style: none; }
.qa details summary::-webkit-details-marker { display: none; }
.qa details[open] summary { margin-bottom: 8px; }
.qa .ans { font-size: 14px; color: var(--ink); background: var(--sage-soft); border-radius: 8px; padding: 10px 12px; }
.qa .exp { font-size: 13.5px; color: var(--ink-2); margin-top: 8px; }

/* ---------------- diagnose ---------------- */
.diag-wrap { width: min(760px, 100%); margin: 0 auto; padding: 44px 24px 80px; }
.diag-head { text-align: center; margin-bottom: 32px; }
.diag-head h1 { font-family: var(--serif); font-size: clamp(28px, 4vw, 38px); font-weight: 600; margin: 0 0 10px; }
.diag-head p { color: var(--ink-2); margin: 0; }

.pick-card { background: var(--surface); border: 1px solid var(--line); border-radius: var(--r-lg); padding: 20px; box-shadow: var(--shadow-1); }
.pick-card .search-box input { height: 48px; font-size: 15px; }
.results { margin-top: 8px; max-height: 280px; overflow-y: auto; }
.result-row { display: flex; align-items: center; gap: 10px; padding: 10px 8px; border-radius: 8px; cursor: pointer; font-size: 14px; }
.result-row:hover, .result-row.on { background: var(--sage-soft); }
.result-row .meta { margin-left: auto; font-size: 12px; color: var(--ink-3); }

.grade-picker { margin-top: 18px; }
.grade-picker .label { font-size: 12px; letter-spacing: .1em; color: var(--ink-3); margin-bottom: 8px; }
.grade-row { display: flex; flex-wrap: wrap; gap: 6px; }
.grade-row button { min-width: 44px; }

.recent { margin-top: 18px; }

.quiz-top { display: flex; align-items: center; gap: 12px; margin-bottom: 18px; }
.progress { flex: 1; height: 5px; background: #ebe5da; border-radius: 4px; overflow: hidden; }
.progress i { display: block; height: 100%; background: var(--sage); border-radius: 4px; transition: width .3s; }
.quiz-count { font-size: 12px; color: var(--ink-3); font-family: var(--mono); }

.quiz-card { background: var(--surface); border: 1px solid var(--line); border-radius: var(--r-lg); padding: 26px 26px 22px; box-shadow: var(--shadow-1); }
.quiz-topic { display: flex; align-items: center; gap: 8px; font-size: 12.5px; color: var(--ink-3); margin-bottom: 14px; }
.quiz-topic b { color: var(--ink-2); font-weight: 600; }
.stem { font-size: 19px; line-height: 1.7; margin: 0 0 18px; font-weight: 500; white-space: pre-wrap; }
.opts { display: grid; gap: 10px; }
.opt-btn {
  display: flex; align-items: center; gap: 12px; width: 100%; text-align: left;
  padding: 13px 14px; border: 1px solid var(--line); border-radius: var(--r-md);
  background: var(--surface); font-size: 15px; cursor: pointer; transition: all .15s;
}
.opt-btn:hover { border-color: var(--sage-line); background: var(--sage-soft); }
.opt-btn .key {
  width: 26px; height: 26px; border-radius: 8px; flex: none;
  display: grid; place-items: center; background: var(--surface-2); font-size: 12px; font-weight: 600;
}
.opt-btn.on { border-color: var(--sage); background: var(--sage-soft); }
.opt-btn.on .key { background: var(--sage); color: #fff; }
.opt-btn.correct { border-color: var(--ok); background: var(--ok-soft); }
.opt-btn.wrong { border-color: var(--bad); background: var(--bad-soft); }
.opt-btn:disabled { cursor: default; }

.answer-row { display: flex; gap: 8px; margin-top: 6px; }
.answer-row input {
  flex: 1; height: 48px; padding: 0 16px; border: 1px solid var(--line); border-radius: var(--r-md);
  font-size: 16px; background: var(--surface);
}
.answer-row input:focus, .search-box input:focus { border-color: var(--sage); outline: none; box-shadow: 0 0 0 3px var(--sage-soft); }
.answer-row input::placeholder, .search-box input::placeholder { color: #a9a196; }

.feedback { margin-top: 18px; border-radius: var(--r-md); padding: 14px 16px; font-size: 14px; line-height: 1.7; }
.feedback.ok { background: var(--ok-soft); color: #24544a; }
.feedback.bad { background: var(--bad-soft); color: #7f3322; }
.feedback.manual { background: var(--warn-soft); color: #7a531a; }
.feedback b { display: block; margin-bottom: 4px; }
.feedback .ref { font-family: var(--mono); font-size: 13px; margin: 6px 0; }
.feedback .act { display: flex; gap: 8px; margin-top: 10px; flex-wrap: wrap; }

.quiz-foot { display: flex; align-items: center; justify-content: space-between; margin-top: 18px; gap: 12px; }
.quiz-foot .hint { font-size: 12px; color: var(--ink-3); }

/* 报告 */
.report-head { margin-bottom: 24px; }
.report-head .kicker { font-size: 12px; letter-spacing: .14em; color: var(--sage); margin-bottom: 10px; }
.report-head h1 { font-family: var(--serif); font-size: clamp(26px, 4vw, 34px); line-height: 1.4; margin: 0 0 10px; font-weight: 600; }
.report-stats { display: grid; grid-template-columns: repeat(5, 1fr); gap: 10px; margin: 22px 0; }
.report-stats div { background: var(--surface); border: 1px solid var(--line); border-radius: var(--r-md); padding: 14px; text-align: center; }
.report-stats b { display: block; font-family: var(--serif); font-size: 26px; font-weight: 600; line-height: 1.2; }
.report-stats span { font-size: 12px; color: var(--ink-3); }

.focus-card {
  border: 1px solid var(--sage-line); background: linear-gradient(150deg, var(--sage-soft), #fffefb 60%);
  border-radius: var(--r-lg); padding: 22px 24px; margin: 20px 0;
}
.focus-card .k { font-size: 11.5px; letter-spacing: .12em; color: var(--sage); margin-bottom: 8px; }
.focus-card h3 { font-family: var(--serif); font-size: 24px; margin: 0 0 8px; font-weight: 600; }
.focus-card p { margin: 0 0 12px; color: var(--ink-2); font-size: 14.5px; }
.focus-card .why { font-size: 13.5px; color: var(--ink-2); background: rgba(255,255,255,.6); border-radius: 8px; padding: 10px 12px; margin-bottom: 14px; }

.path-list { display: grid; gap: 8px; }
.path-row {
  display: flex; align-items: center; gap: 12px; padding: 12px 14px;
  background: var(--surface); border: 1px solid var(--line); border-radius: var(--r-md);
}
.path-row .idx { font-family: var(--mono); font-size: 11px; color: var(--ink-3); width: 18px; flex: none; }
.path-row .body { flex: 1; min-width: 0; }
.path-row .body b { display: block; font-size: 14.5px; font-weight: 600; }
.path-row .body span { font-size: 12px; color: var(--ink-3); }
.path-row .st { font-size: 11.5px; padding: 2px 8px; border-radius: 999px; white-space: nowrap; }
.st.weak { background: var(--bad-soft); color: var(--bad); }
.st.shaky { background: var(--warn-soft); color: var(--warn); }
.st.mastered { background: var(--ok-soft); color: var(--ok); }
.st.unknown { background: var(--surface-2); color: var(--ink-3); }

.path-graph { background: var(--surface); border: 1px solid var(--line); border-radius: var(--r-md); padding: 10px; margin-top: 10px; overflow: hidden; }
.path-graph svg { width: 100%; height: auto; }

.report-actions { display: flex; flex-wrap: wrap; gap: 10px; margin-top: 26px; }
details.more-block { border-top: 1px solid var(--line); padding: 14px 0; }
details.more-block summary { cursor: pointer; list-style: none; font-size: 14px; color: var(--ink-2); display: flex; align-items: center; gap: 8px; }
details.more-block summary::-webkit-details-marker { display: none; }
details.more-block summary::before { content: "+"; font-family: var(--mono); color: var(--ink-3); }
details.more-block[open] summary::before { content: "−"; }
details.more-block .rows { padding: 10px 0 0 18px; display: flex; flex-wrap: wrap; gap: 6px; }

/* ---------------- search overlay ---------------- */
.overlay {
  position: fixed; inset: 0; z-index: 80; background: rgba(31, 29, 25, .32);
  display: flex; justify-content: center; padding-top: 12vh;
  backdrop-filter: blur(2px);
}
.overlay .panel {
  width: min(620px, calc(100% - 32px)); height: fit-content; max-height: 70vh;
  background: var(--surface); border-radius: var(--r-lg); border: 1px solid var(--line);
  box-shadow: var(--shadow-2); overflow: hidden; display: flex; flex-direction: column;
}
.overlay .panel input {
  height: 56px; border: 0; border-bottom: 1px solid var(--line-2); padding: 0 18px;
  font-size: 16px; background: transparent; outline: none;
}
.overlay .hits { overflow-y: auto; padding: 8px; }
.hit { display: flex; align-items: center; gap: 10px; padding: 10px 12px; border-radius: 10px; cursor: pointer; font-size: 14px; }
.hit:hover, .hit.on { background: var(--sage-soft); }
.hit .meta { margin-left: auto; font-size: 12px; color: var(--ink-3); }
.hit mark { background: none; color: var(--sage); font-weight: 600; }
.overlay .tip { padding: 10px 16px; border-top: 1px solid var(--line-2); font-size: 12px; color: var(--ink-3); display: flex; gap: 14px; }

/* ---------------- misc ---------------- */
.loading { padding: 80px 0; text-align: center; color: var(--ink-3); font-size: 14px; }
.error-box { padding: 24px; border: 1px solid var(--clay-line); background: var(--clay-soft); border-radius: var(--r-md); color: #7f3322; font-size: 14px; }
.divider { height: 1px; background: var(--line); margin: 24px 0; }
.skip-link { position: absolute; left: -9999px; }
.skip-link:focus { left: 12px; top: 12px; background: #fff; padding: 8px 12px; border-radius: 8px; z-index: 100; }

@media (max-width: 1080px) {
  .hero-grid { grid-template-columns: 1fr; gap: 32px; }
  .map-shell { grid-template-columns: 260px minmax(0, 1fr); }
  .detail { position: fixed; right: 0; top: var(--header-h); bottom: 0; width: min(380px, 88vw); z-index: 50; box-shadow: var(--shadow-2); transform: translateX(100%); transition: transform .25s; }
  .detail.open { transform: none; }
  .detail-close { display: grid !important; }
  .topic-layout { grid-template-columns: 1fr; gap: 30px; }
}
@media (max-width: 860px) {
  .header-right .btn { display: none; }
  .site-header .wrap { gap: 10px; }
  .nav a { padding: 6px 9px; font-size: 13.5px; }
  .detail-inner { padding-top: 54px; }
  .hero { padding: 34px 0 28px; }
  .stat-strip { grid-template-columns: repeat(2, 1fr); }
  .stat-strip div:nth-child(3) { border-left: 0; }
  .stat-strip div:nth-child(n+3) { border-top: 1px solid var(--line-2); }
  .steps { grid-template-columns: 1fr; }
  .grade-grid { grid-template-columns: 1fr 1fr; }
  .section { padding: 40px 0; }
  .map-shell { display: block; height: auto; }
  .sidebar { border-right: 0; height: auto; }
  .list { max-height: none; overflow: visible; }
  .graph-pane { display: none; border-top: 1px solid var(--line); }
  .graph-pane.show { display: flex; height: 62vh; }
  .mobile-bar { display: flex !important; }
  .detail { width: 100%; }
  .report-stats { grid-template-columns: repeat(3, 1fr); }
  .report-stats div { padding: 12px 8px; }
  .diag-wrap { padding: 28px 18px 60px; }
  .quiz-card { padding: 20px 18px; }
}
@media (max-width: 520px) {
  .hero h1.display { font-size: clamp(28px, 8vw, 38px); }
  .grade-grid { grid-template-columns: 1fr; }
  .report-stats { grid-template-columns: 1fr 1fr; }
  .report-stats div:last-child { grid-column: span 2; }
  .brand b { font-size: 15px; }
  .hero-actions .btn { flex: 1; }
  .topic-layout { padding-top: 24px; }
  .section-head { flex-direction: column; align-items: flex-start; gap: 6px; }
}
.mobile-bar { display: none; position: sticky; bottom: 0; z-index: 30; gap: 8px; padding: 10px 14px; background: rgba(250,248,244,.94); border-top: 1px solid var(--line); backdrop-filter: blur(8px); }
.detail-close { display: none; position: absolute; top: 10px; right: 10px; width: 34px; height: 34px; border-radius: 8px; border: 1px solid var(--line); background: var(--surface); place-items: center; cursor: pointer; z-index: 2; }

@media print {
  .site-header, .report-actions, .mobile-bar, .path-graph { display: none !important; }
  body { background: #fff; }
  .diag-wrap { width: 100%; padding: 0; }
  .focus-card, .path-row { break-inside: avoid; }
}