/* 中小学数学知识图谱：全站配色、字号、导航。浏览页与诊断页共用。 */

:root {
  color-scheme: light;
  --bg: #f3f7fb;
  --bg-elev: #ffffff;
  --bg-muted: #e7eef6;
  --text: #162033;
  --muted: #5c6d82;
  --line: #d5e0eb;
  --brand: #0f766e;
  --brand-strong: #115e59;
  --brand-soft: #d5f3ee;
  --on-brand: #ffffff;
  --junior: #1d4ed8;
  --junior-soft: #dbe7ff;
  --focus: #0f766e;
  --shadow: 0 10px 28px rgba(22, 40, 70, 0.07);
  --radius: 16px;
  --radius-sm: 12px;
  --font: "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans CJK SC", "Noto Sans SC", "Source Han Sans SC", sans-serif;
  --fs: 17px;
  --ok: #157a3a;
  --ok-bg: #dcfce7;
  --on-ok: #ffffff;
  --bad: #b91c1c;
  --bad-bg: #fee2e2;
  --on-bad: #ffffff;
  --warn: #9a3412;
  --warn-bg: #ffedd5;
  --unk: #475569;
  --unk-bg: #e8eef6;
  --accent: #0f766e;
  --panel: #ffffff;
  --node-primary: #0f766e;
  --node-primary-bg: #d5f3ee;
  --node-junior: #1d4ed8;
  --node-junior-bg: #dbe7ff;
  --node-senior: #a21caf;
  --node-senior-bg: #fae8ff;
  --node-current-bg: #fff4e5;
  --node-current-border: #ea580c;
  --node-text: #162033;
  --edge: #526274;
  --edge-soft: #8aa0b4;
  --hard-bg: #ffedd5;
  --hard-fg: #9a3412;
  --soft-bg: #e7eef6;
  --soft-fg: #475569;
  --diagram-ok-bg: #dcfce7;
  --diagram-ok: #157a3a;
  --diagram-bad-bg: #fee2e2;
  --diagram-bad: #b91c1c;
  --diagram-unk-bg: #f1f5f9;
  --diagram-unk: #64748b;
  --diagram-shaky-bg: #fef3c7;
  --diagram-shaky: #b45309;
  --diagram-text: #162033;
  --diagram-edge: #64748b;
}

@media (prefers-color-scheme: dark) {
  :root {
    color-scheme: dark;
    --bg: #0e1520;
    --bg-elev: #172232;
    --bg-muted: #223044;
    --text: #e7eef8;
    --muted: #a4b4c6;
    --line: #2d3e54;
    --brand: #2dd4bf;
    --brand-strong: #5eead4;
    --brand-soft: #134e4a;
    --on-brand: #042f2e;
    --junior: #93c5fd;
    --junior-soft: #1e3a8a;
    --focus: #5eead4;
    --shadow: 0 10px 28px rgba(0, 0, 0, 0.35);
    --ok: #4ade80;
    --ok-bg: #14532d;
    --on-ok: #052e16;
    --bad: #fca5a5;
    --bad-bg: #7f1d1d;
    --on-bad: #450a0a;
    --warn: #fdba74;
    --warn-bg: #7c2d12;
    --unk: #cbd5e1;
    --unk-bg: #223044;
    --accent: #2dd4bf;
    --panel: #172232;
    --node-primary: #5eead4;
    --node-primary-bg: #115e59;
    --node-junior: #93c5fd;
    --node-junior-bg: #1e3a8a;
    --node-senior: #f0abfc;
    --node-senior-bg: #4a044e;
    --node-current-bg: #7c2d12;
    --node-current-border: #fdba74;
    --node-text: #f8fafc;
    --edge: #94a3b8;
    --edge-soft: #64748b;
    --hard-bg: #7c2d12;
    --hard-fg: #ffedd5;
    --soft-bg: #223044;
    --soft-fg: #cbd5e1;
  }
}

@media print {
  :root {
    --bg: #fff;
    --bg-elev: #fff;
    --bg-muted: #f4f7fb;
    --text: #162033;
    --muted: #475569;
    --line: #d5dde6;
    --panel: #fff;
    --shadow: none;
  }
}

*, *::before, *::after { box-sizing: border-box; }
[hidden] { display: none !important; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  font-family: var(--font);
  font-size: var(--fs);
  line-height: 1.65;
  color: var(--text);
  background: var(--bg);
}
img { max-width: 100%; height: auto; }
.node-tip {
  position: absolute;
  z-index: 6;
  max-width: min(280px, calc(100% - 16px));
  padding: 6px 10px;
  border-radius: 10px;
  background: var(--text);
  color: var(--bg);
  font-size: 0.92rem;
  font-weight: 700;
  line-height: 1.45;
  pointer-events: none;
  box-shadow: var(--shadow);
  overflow-wrap: anywhere;
}
code { overflow-wrap: anywhere; }
:focus-visible { outline: 3px solid var(--focus); outline-offset: 2px; }
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { transition: none !important; scroll-behavior: auto !important; }
}

.site-header {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px 16px;
  padding: 10px 16px;
  background: var(--bg-elev);
  border-bottom: 1px solid var(--line);
  max-width: 100%;
}
.brand {
  display: flex;
  align-items: center;
  gap: 8px;
  min-height: 44px;
  min-width: 0;
  color: inherit;
  text-decoration: none;
  font-weight: 800;
}
.logo { color: var(--brand); flex: none; display: block; }
.brand-name { overflow-wrap: anywhere; }
.site-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 4px;
  margin-left: auto;
  min-width: 0;
  max-width: 100%;
}
.nav-link {
  display: inline-flex;
  align-items: center;
  min-height: 44px;
  padding: 8px 12px;
  border-radius: 999px;
  color: var(--text);
  text-decoration: none;
  font-weight: 700;
}
.nav-link:hover { background: var(--bg-muted); }
.nav-link.active, .nav-link[aria-current="page"] {
  background: var(--brand-soft);
  color: var(--brand-strong);
}
@media (max-width: 720px) {
  .site-nav { flex: 1 1 100%; margin-left: 0; }
}

.site-footer {
  padding: 14px 16px 18px;
  text-align: center;
  color: var(--muted);
  font-size: 0.92rem;
  border-top: 1px solid var(--line);
  max-width: 100%;
}
.site-footer p { margin: 0; overflow-wrap: anywhere; }
.site-footer a { color: var(--brand-strong); font-weight: 700; }

button, .btn {
  font: inherit;
  font-weight: 700;
  min-height: 44px;
  padding: 10px 16px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--line);
  background: var(--bg-elev);
  color: var(--text);
  cursor: pointer;
}
button.primary, .btn-primary {
  background: var(--brand);
  border-color: transparent;
  color: var(--on-brand);
}
button.primary:hover, .btn-primary:hover { filter: brightness(0.96); }
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  text-decoration: none;
  text-align: center;
}
.btn-lg { min-height: 52px; padding: 12px 20px; font-size: 1.05rem; }
.btn-block { width: 100%; }

input[type="search"], input[type="text"], input[type="number"], select, textarea {
  font: inherit;
  color: var(--text);
  background: var(--bg-elev);
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  padding: 10px 12px;
  min-height: 44px;
  max-width: 100%;
}
textarea { min-height: 96px; }
.search-lg { width: 100%; font-size: 1.08rem; min-height: 52px; }

.stage-tabs { display: flex; flex-wrap: wrap; gap: 8px; }
.stage-tab { border-radius: 999px; }
.stage-tab.on, .stage-tab[aria-selected="true"] {
  background: var(--brand);
  color: var(--on-brand);
  border-color: transparent;
}

.badge {
  display: inline-flex;
  align-items: center;
  min-height: 24px;
  padding: 0 8px;
  border-radius: 999px;
  font-size: 0.78rem;
  font-weight: 800;
  white-space: nowrap;
}
.badge.hard { background: var(--hard-bg); color: var(--hard-fg); }
.badge.soft { background: var(--soft-bg); color: var(--soft-fg); }

/* 首页 */
.home { width: min(1080px, 100%); margin: 0 auto; padding: 18px 16px 40px; }
.hero {
  background:
    radial-gradient(820px 240px at 0% -20%, rgba(15, 118, 110, 0.16), transparent 60%),
    radial-gradient(640px 220px at 100% 0%, rgba(29, 78, 216, 0.12), transparent 55%),
    var(--bg-elev);
  border: 1px solid var(--line);
  border-radius: 24px;
  padding: 28px 22px 22px;
  box-shadow: var(--shadow);
}
.eyebrow { margin: 0 0 8px; color: var(--brand-strong); font-weight: 800; }
.hero h1 { margin: 0 0 10px; font-size: clamp(1.7rem, 4vw, 2.35rem); line-height: 1.25; }
.lede { margin: 0 0 18px; font-size: 1.12rem; max-width: 40em; }
.hero-actions { display: flex; flex-wrap: wrap; gap: 10px; }
.hero-actions .btn { flex: 1 1 200px; }
.quiet-link { margin: 12px 0 0; }
.quiet-link a { color: var(--brand-strong); font-weight: 700; }

.section-title { margin: 28px 0 12px; font-size: 1.3rem; }
.steps {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 12px;
}
.steps li {
  background: var(--bg-elev);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 16px;
  box-shadow: var(--shadow);
  min-width: 0;
}
.step-no {
  display: inline-flex;
  width: 36px;
  height: 36px;
  border-radius: 50%;
  align-items: center;
  justify-content: center;
  background: var(--brand);
  color: var(--on-brand);
  font-weight: 800;
}
.steps h3 { margin: 8px 0 4px; font-size: 1.12rem; }
.steps p { margin: 0; color: var(--muted); }

.stat-grid, .grade-grid {
  display: grid;
  gap: 12px;
}
.stat-grid { grid-template-columns: repeat(4, minmax(0, 1fr)); }
.grade-grid { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.stat-card, a.grade-card {
  background: var(--bg-elev);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  min-width: 0;
}
.stat-card { padding: 14px 16px; }
.stat-num { font-size: 2rem; font-weight: 800; line-height: 1.1; color: var(--brand-strong); }
.stat-label { color: var(--muted); font-weight: 700; }
.stat-note { color: var(--muted); margin: 8px 0 0; }
a.grade-card {
  display: flex;
  flex-direction: column;
  gap: 2px;
  padding: 14px;
  min-height: 104px;
  text-decoration: none;
  color: inherit;
  box-shadow: inset 0 4px 0 var(--node-primary), var(--shadow);
}
a.grade-card.is-junior { box-shadow: inset 0 4px 0 var(--node-junior), var(--shadow); }
a.grade-card.is-senior { box-shadow: inset 0 4px 0 var(--node-senior), var(--shadow); }
a.grade-card:hover { border-color: var(--brand); }
a.grade-card strong { font-size: 1.15rem; }
.grade-stage { color: var(--muted); font-size: 0.88rem; font-weight: 700; }
.grade-count { font-weight: 800; }
.load-error {
  background: var(--bad-bg);
  color: var(--text);
  border-radius: var(--radius-sm);
  padding: 12px 14px;
  margin-top: 12px;
}
@media (max-width: 800px) {
  .steps { grid-template-columns: 1fr; }
  .stat-grid, .grade-grid { grid-template-columns: 1fr 1fr; }
}