/* ============================================================
   統計讀心術 · Stat Literacy Lab — 全站樣式
   血統：cool-dataviz × simulation-lab（dark，科學閱讀殼 + 模擬舞台）
   色值只出現在 :root。元件一律 var(--token)。所有章頁共用，不准各自複製。
   ============================================================ */

:root {
  color-scheme: dark;

  /* ── 底層與面板 ── */
  --bg: #0b0f16;            /* 閱讀殼：深藍黑 */
  --bg2: #0f141d;
  --panel: #141b26;         /* 卡片 */
  --panel-2: #18212e;       /* 卡片第二階 / diff */
  --stage: #0a1220;         /* 模擬舞台（更深一階） */
  --stage-2: #0d1626;
  --border: #24303f;
  --border-strong: #35455c;

  /* ── 三層文字 ── */
  --text: #e8eef6;
  --text-dim: #9aa8ba;
  --text-muted: #647082;
  --stage-text: #f2f7fc;    /* 舞台上文字亮一階 */

  /* ── 主 accent（藍）+ 宣告過的第二語意（紫）── */
  --accent: #5aa2f7;
  --accent-bright: #86bdff;
  --accent-soft: rgba(90, 162, 247, .13);
  --accent-press: #3f86e0;
  --violet: #a78bfa;        /* 第二語意色（僅用於「對照 / 另一組」） */
  --violet-soft: rgba(167, 139, 250, .14);

  /* ── 語意色（dark 亮階）── */
  --good: #34d399;   --good-soft: rgba(52, 211, 153, .13);
  --warn: #fbbf24;   --warn-soft: rgba(251, 191, 36, .13);
  --bad: #fb7185;    --bad-soft: rgba(251, 113, 133, .13);
  --info: #22d3ee;   --info-soft: rgba(34, 211, 238, .13);

  /* ── 圖表分類色（categorical，全站唯一來源）── */
  --c-1: #5aa2f7;   /* 藍 — 主 / 第一組 */
  --c-2: #f472b6;   /* 粉 — 第二組 */
  --c-3: #34d399;   /* 綠 — 對 / 陽性 */
  --c-4: #fbbf24;   /* 黃 — 警示 / 邊界 */
  --c-5: #a78bfa;   /* 紫 — 對照 */
  --c-6: #22d3ee;   /* 青 */
  --c-7: #fb7185;   /* 紅 — 錯 / 陰性 */
  --c-8: #94a3b8;   /* 灰 — 母體 / 背景 */

  --r-container: 14px;
  --r-control: 9px;
  --focus: 0 0 0 3px rgba(90, 162, 247, .4);
  --maxw: 780px;
  --maxw-wide: 1080px;
  --shadow-lab: 0 1px 0 rgba(255,255,255,.02) inset, 0 18px 40px -28px rgba(0,0,0,.9);
}

/* ── reset & base ─────────────────────────────────── */
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  background:
    radial-gradient(1200px 560px at 50% -10%, rgba(90,162,247,.08), transparent 70%),
    var(--bg);
  color: var(--text);
  font-family: 'Noto Sans TC', Inter, system-ui, -apple-system, "PingFang TC", sans-serif;
  font-size: 16.5px;
  line-height: 1.8;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}
.serif { font-family: 'Fraunces', Georgia, serif; }
.mono { font-family: 'JetBrains Mono', ui-monospace, SFMono-Regular, monospace; }
a { color: var(--accent-bright); text-decoration: none; }
a:hover { text-decoration: underline; text-underline-offset: 3px; }
img { max-width: 100%; height: auto; }
::selection { background: var(--accent-soft); }
.num, .tnum { font-variant-numeric: tabular-nums; }

/* ── layout ───────────────────────────────────────── */
.container { max-width: var(--maxw); margin: 0 auto; padding: 0 24px 110px; }
main.container { padding-top: 42px; }
section { margin: 58px 0; }
section:first-of-type { margin-top: 0; }
.wide { max-width: var(--maxw-wide); }

/* ── type ramp ────────────────────────────────────── */
.kicker {
  font-family: 'JetBrains Mono', ui-monospace, monospace;
  font-size: 10.5px; letter-spacing: .2em; text-transform: uppercase;
  color: var(--accent); display: inline-block; margin: 0 0 14px;
}
h1 {
  font-family: 'Fraunces', Georgia, serif;
  font-size: 41px; line-height: 1.18; font-weight: 600; letter-spacing: -.015em;
  margin: 0 0 20px; color: var(--text);
}
h1 em { color: var(--accent); font-style: italic; font-weight: 500; }
h2 {
  font-family: 'Fraunces', Georgia, serif;
  font-size: 27px; line-height: 1.3; font-weight: 600; margin: 0 0 15px; letter-spacing: -.01em;
}
h3 { font-size: 19px; line-height: 1.45; font-weight: 650; margin: 30px 0 10px; color: var(--text); }
p { margin: 15px 0; }
.lead { font-size: 18.5px; color: var(--text-dim); line-height: 1.75; margin: 0 0 8px; }
.lead b { color: var(--text); font-weight: 600; }
strong, b { font-weight: 650; color: var(--text); }
.dim { color: var(--text-dim); }
.muted { color: var(--text-muted); }
.en { font-family: Inter, system-ui, sans-serif; font-style: normal; color: var(--text-dim); }
.term { color: var(--accent-bright); font-weight: 600; }
code, .kbd {
  font-family: 'JetBrains Mono', ui-monospace, monospace; font-size: .88em;
  background: var(--accent-soft); color: var(--accent-bright);
  padding: 1px 6px; border-radius: 5px;
}
ul, ol { padding-left: 22px; }
li { margin: 7px 0; color: var(--text-dim); }
li b, li strong { color: var(--text); }
hr { border: 0; border-top: 1px solid var(--border); margin: 34px 0; }

/* ── site header ──────────────────────────────────── */
.site-header {
  position: sticky; top: 0; z-index: 40;
  background: color-mix(in srgb, var(--bg) 90%, transparent);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--border);
}
.site-header-in {
  max-width: 1100px; margin: 0 auto; padding: 13px 24px;
  display: flex; align-items: center; justify-content: space-between; gap: 16px; flex-wrap: wrap;
}
.site-brand { display: flex; align-items: baseline; gap: 10px; text-decoration: none; color: inherit; }
.site-brand:hover { text-decoration: none; }
.site-brand .mark {
  font-family: 'Fraunces', Georgia, serif; font-size: 19px; font-weight: 600; color: var(--text); letter-spacing: -.01em;
}
.site-brand .mark em { color: var(--accent); font-style: italic; font-weight: 500; }
.site-brand .sub {
  font-family: 'JetBrains Mono', ui-monospace, monospace; font-size: 10px;
  letter-spacing: .16em; text-transform: uppercase; color: var(--text-muted);
}
.site-header-right { display: flex; align-items: center; gap: 14px; flex-wrap: wrap; }
.site-header a.tolink {
  font-family: 'JetBrains Mono', ui-monospace, monospace; font-size: 11px;
  letter-spacing: .1em; text-transform: uppercase; color: var(--text-dim); transition: color .15s;
}
.site-header a.tolink:hover { color: var(--accent-bright); text-decoration: none; }
.toc-progress {
  display: inline-flex; align-items: center; gap: 9px;
  font-family: 'JetBrains Mono', ui-monospace, monospace; font-size: 11px; letter-spacing: .06em;
  color: var(--text-dim); border: 1px solid var(--border); background: var(--panel);
  padding: 5px 12px; border-radius: 999px;
}
.toc-progress .sep { color: var(--text-muted); }
.toc-progress .xp { color: var(--accent-bright); font-weight: 500; }
.toc-progress .xp .num { color: var(--accent-bright); }

/* ── hero ─────────────────────────────────────────── */
.hero { margin-bottom: 40px; }
.hero .promise { font-size: 18.5px; line-height: 1.75; color: var(--text-dim); margin: 0; max-width: 62ch; }
.hero .promise b { color: var(--text); }
.level-line { display: flex; align-items: center; gap: 10px; margin: 0 0 16px; flex-wrap: wrap; }

/* ── level-pill 級別膠囊（6 級，用 accent 濃淡不搞彩虹）── */
.level-pill {
  display: inline-flex; align-items: center; gap: 7px;
  font-family: 'JetBrains Mono', ui-monospace, monospace; font-size: 10.5px;
  letter-spacing: .12em; text-transform: uppercase;
  padding: 4px 11px 4px 9px; border-radius: 999px;
  border: 1px solid var(--border-strong); color: var(--text-dim); background: var(--panel);
}
.level-pill::before {
  content: ""; width: 9px; height: 9px; border-radius: 2px;
  background: var(--accent); border: 1px solid rgba(0,0,0,.3);
}
.level-pill.l0 { color: var(--text-dim); }
.level-pill.l0::before { background: color-mix(in srgb, var(--accent) 30%, var(--text-muted)); }
.level-pill.l1::before { background: color-mix(in srgb, var(--accent) 55%, var(--text-muted)); }
.level-pill.l2 { border-color: color-mix(in srgb, var(--accent) 40%, var(--border)); }
.level-pill.l2::before { background: color-mix(in srgb, var(--accent) 75%, var(--text-muted)); }
.level-pill.l3 { border-color: color-mix(in srgb, var(--accent) 55%, var(--border)); }
.level-pill.l3::before { background: var(--accent); }
.level-pill.l4 { color: var(--accent-bright); border-color: color-mix(in srgb, var(--accent) 70%, var(--border)); }
.level-pill.l4::before { background: var(--accent-bright); }
.level-pill.l5 { color: var(--accent-bright); border-color: var(--accent); }
.level-pill.l5::before { background: var(--accent-bright); box-shadow: 0 0 8px var(--accent); }
.level-pill.l6 { color: var(--violet); border-color: color-mix(in srgb, var(--violet) 55%, var(--border)); }
.level-pill.l6::before { background: var(--violet); }

/* ── card / callout ───────────────────────────────── */
.card { background: var(--panel); border: 1px solid var(--border); border-radius: var(--r-container); padding: 20px 22px; }
.card .t { font-size: 15px; font-weight: 650; margin: 0 0 8px; color: var(--text); }
.card p, .card li { color: var(--text-dim); }
.card p:first-child { margin-top: 0; }
.card p:last-child { margin-bottom: 0; }

.callout {
  background: var(--panel); border: 1px solid var(--border); border-left: 4px solid var(--accent);
  border-radius: var(--r-control); padding: 16px 18px 16px 20px; margin: 22px 0;
}
.callout .t {
  font-family: 'JetBrains Mono', ui-monospace, monospace; font-size: 10.5px;
  letter-spacing: .14em; text-transform: uppercase; color: var(--accent); margin: 0 0 8px;
}
.callout p { margin: 0; color: var(--text-dim); font-size: 15.5px; }
.callout p + p { margin-top: 10px; }
.callout.warn { border-left-color: var(--warn); }
.callout.warn .t { color: var(--warn); }
.callout.bad { border-left-color: var(--bad); }
.callout.bad .t { color: var(--bad); }
.callout.good { border-left-color: var(--good); }
.callout.good .t { color: var(--good); }
.callout.info { border-left-color: var(--info); }
.callout.info .t { color: var(--info); }
.callout.violet { border-left-color: var(--violet); }
.callout.violet .t { color: var(--violet); }

.grid2 { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }
.grid3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; }

/* ── 白話盒 / 一句話 / paper 盒 ─────────────────────── */
.plain {
  background: linear-gradient(180deg, var(--panel-2), var(--panel));
  border: 1px solid var(--border-strong); border-radius: var(--r-container); padding: 20px 22px; margin: 24px 0;
}
.plain::before {
  content: "白話講"; display: inline-block;
  font-family: 'JetBrains Mono', ui-monospace, monospace; font-size: 10.5px;
  letter-spacing: .14em; text-transform: uppercase; color: var(--accent); margin: 0 0 10px;
}
.plain p { margin: 8px 0; color: var(--text); font-size: 16px; }
.plain p:last-child { margin-bottom: 0; }

.oneline {
  border: 1px dashed var(--border-strong); border-radius: var(--r-control);
  padding: 14px 18px; margin: 20px 0; color: var(--text);
  font-size: 16.5px; background: var(--accent-soft);
}
.oneline b { color: var(--accent-bright); }

.paperbox {
  background: var(--panel); border: 1px solid var(--border); border-radius: var(--r-container);
  padding: 0; margin: 24px 0; overflow: hidden;
}
.paperbox .cap {
  font-family: 'JetBrains Mono', ui-monospace, monospace; font-size: 10.5px;
  letter-spacing: .12em; text-transform: uppercase; color: var(--text-muted);
  padding: 9px 18px; border-bottom: 1px solid var(--border); background: var(--bg2);
  display: flex; align-items: center; gap: 8px;
}
.paperbox .cap::before { content: "PAPER"; color: var(--accent); }
.paperbox .body { padding: 16px 20px; }
.paperbox .quote {
  font-family: Inter, Georgia, serif; font-size: 15px; line-height: 1.7;
  color: var(--text-dim); border-left: 2px solid var(--accent); padding-left: 14px; margin: 0 0 12px;
}
.paperbox .decode { color: var(--text); font-size: 15px; margin: 0; }
.paperbox .decode b { color: var(--accent-bright); }

/* ── high-yield / freq 標記 ─────────────────────────── */
.hy { font-family: 'JetBrains Mono', ui-monospace, monospace; font-size: 12px; letter-spacing: .06em; color: var(--warn); }
.hy.lo { color: var(--text-muted); }

/* ── data / stat table ────────────────────────────── */
.tbl-wrap { overflow-x: auto; margin: 22px 0; border: 1px solid var(--border); border-radius: var(--r-container); }
table.stat { width: 100%; border-collapse: collapse; font-size: 14.5px; }
table.stat th {
  font-family: 'JetBrains Mono', ui-monospace, monospace; font-size: 10.5px;
  letter-spacing: .1em; text-transform: uppercase; color: var(--text-muted); font-weight: 500;
  text-align: left; padding: 11px 14px; border-bottom: 1px solid var(--border); background: var(--bg2); white-space: nowrap;
}
table.stat td { padding: 11px 14px; border-bottom: 1px solid var(--border); color: var(--text-dim); vertical-align: top; }
table.stat tr:last-child td { border-bottom: 0; }
table.stat td.num, table.stat th.num { text-align: right; font-variant-numeric: tabular-nums; }
table.stat td b { color: var(--text); }
table.stat tr:hover td { background: color-mix(in srgb, var(--accent) 5%, transparent); }

/* ── code-block ───────────────────────────────────── */
.code-block { background: var(--bg2); border: 1px solid var(--border); border-left: 2px solid var(--accent); border-radius: var(--r-control); margin: 20px 0; overflow: hidden; }
.code-block .cap {
  font-family: 'JetBrains Mono', ui-monospace, monospace; font-size: 10.5px; letter-spacing: .1em;
  text-transform: uppercase; color: var(--text-muted); padding: 8px 16px; border-bottom: 1px solid var(--border); background: var(--panel);
}
.code-block pre { margin: 0; padding: 16px; overflow-x: auto; font-family: 'JetBrains Mono', ui-monospace, monospace; font-size: 13.5px; line-height: 1.75; color: var(--text); white-space: pre; tab-size: 2; }
.code-block pre .cm { color: var(--text-muted); }
.code-block pre .st { color: var(--good); }
.code-block pre .kw { color: var(--accent-bright); }
.code-block pre .nm { color: var(--violet); }

/* ============================================================
   互動實驗室外殼 interactive-stage / lab
   ============================================================ */
.interactive-stage, .lab {
  background:
    radial-gradient(700px 240px at 50% -20%, rgba(90,162,247,.06), transparent 70%),
    var(--stage);
  border: 1px solid var(--border-strong); border-radius: var(--r-container);
  padding: 20px 22px 22px; margin: 26px 0; box-shadow: var(--shadow-lab);
  transition: border-color .2s;
}
.interactive-stage.done, .lab.done { border-color: color-mix(in srgb, var(--accent) 60%, var(--border-strong)); }
.lab-head { display: flex; align-items: baseline; justify-content: space-between; gap: 12px; flex-wrap: wrap; margin-bottom: 3px; }
.lab-kicker {
  font-family: 'JetBrains Mono', ui-monospace, monospace; font-size: 10.5px;
  letter-spacing: .16em; text-transform: uppercase; color: var(--accent);
}
.lab-tag {
  font-family: 'JetBrains Mono', ui-monospace, monospace; font-size: 10px; letter-spacing: .1em;
  text-transform: uppercase; color: var(--text-muted); border: 1px solid var(--border); border-radius: 999px; padding: 2px 9px;
}
.lab h3, .lab .lab-title { font-size: 18px; font-weight: 650; margin: 8px 0 6px; color: var(--stage-text); }
.lab-desc { font-size: 14.5px; color: var(--text-dim); margin: 0 0 16px; }

/* canvas / svg 舞台 */
.lab-canvas-wrap {
  position: relative; background: var(--stage-2); border: 1px solid var(--border);
  border-radius: var(--r-control); overflow: hidden;
}
.lab-canvas-wrap canvas, .lab-canvas-wrap svg { display: block; width: 100%; height: auto; }
.lab-svg { display: block; width: 100%; height: auto; background: var(--stage-2); border: 1px solid var(--border); border-radius: var(--r-control); }

/* 控制面板 */
.lab-controls { display: flex; flex-wrap: wrap; gap: 14px 20px; align-items: flex-end; margin: 16px 0 4px; }
.control { display: flex; flex-direction: column; gap: 6px; min-width: 150px; flex: 1 1 170px; }
.control > .clabel {
  font-family: 'JetBrains Mono', ui-monospace, monospace; font-size: 10.5px; letter-spacing: .08em;
  text-transform: uppercase; color: var(--text-muted); display: flex; justify-content: space-between; gap: 8px; align-items: baseline;
}
.control > .clabel .cval { color: var(--accent-bright); font-size: 12px; letter-spacing: 0; font-variant-numeric: tabular-nums; }

/* range slider（跨瀏覽器） */
input[type=range] {
  -webkit-appearance: none; appearance: none; width: 100%; height: 4px; border-radius: 999px;
  background: var(--border-strong); outline: none; cursor: pointer; margin: 8px 0;
}
input[type=range]::-webkit-slider-thumb {
  -webkit-appearance: none; appearance: none; width: 16px; height: 16px; border-radius: 50%;
  background: var(--accent); border: 2px solid var(--stage); box-shadow: 0 0 0 1px var(--accent); transition: transform .1s, background .15s;
}
input[type=range]::-webkit-slider-thumb:hover { background: var(--accent-bright); transform: scale(1.12); }
input[type=range]::-moz-range-thumb { width: 16px; height: 16px; border-radius: 50%; background: var(--accent); border: 2px solid var(--stage); }
input[type=range]:focus-visible { box-shadow: var(--focus); }

/* toggle / segmented / scenario buttons */
.seg { display: inline-flex; border: 1px solid var(--border-strong); border-radius: var(--r-control); overflow: hidden; background: var(--panel); }
.seg button {
  font-family: 'Noto Sans TC', Inter, sans-serif; font-size: 13px; font-weight: 500;
  padding: 7px 13px; border: 0; background: transparent; color: var(--text-dim); cursor: pointer; transition: background .15s, color .15s;
  border-right: 1px solid var(--border);
}
.seg button:last-child { border-right: 0; }
.seg button:hover { color: var(--text); }
.seg button.on { background: var(--accent); color: #08101d; font-weight: 600; }
.seg button:focus-visible { outline: none; box-shadow: var(--focus); z-index: 1; }

/* readout 指標（帶單位，tabular） */
.readout { display: grid; grid-template-columns: repeat(auto-fit, minmax(120px, 1fr)); gap: 10px; margin-top: 16px; }
.metric {
  background: var(--panel); border: 1px solid var(--border); border-radius: var(--r-control); padding: 11px 13px;
}
.metric .k {
  font-family: 'JetBrains Mono', ui-monospace, monospace; font-size: 9.5px; letter-spacing: .1em;
  text-transform: uppercase; color: var(--text-muted); display: block; margin-bottom: 4px;
}
.metric .v {
  font-family: 'JetBrains Mono', ui-monospace, monospace; font-size: 21px; font-weight: 500;
  color: var(--stage-text); font-variant-numeric: tabular-nums; line-height: 1.1;
}
.metric .v .u { font-size: 11px; color: var(--text-muted); margin-left: 3px; font-weight: 400; }
.metric.accent .v { color: var(--accent-bright); }
.metric.good .v { color: var(--good); }
.metric.warn .v { color: var(--warn); }
.metric.bad .v { color: var(--bad); }
.metric.violet .v { color: var(--violet); }

/* legend */
.legend { display: flex; flex-wrap: wrap; gap: 8px 16px; margin-top: 12px; font-size: 12.5px; color: var(--text-dim); }
.legend .li { display: inline-flex; align-items: center; gap: 6px; }
.legend .sw { width: 12px; height: 12px; border-radius: 3px; flex: none; }

/* done banner */
.lab-done {
  display: none; align-items: center; gap: 10px; margin-top: 16px; padding: 11px 15px; border-radius: var(--r-control);
  background: var(--accent-soft); border: 1px solid color-mix(in srgb, var(--accent) 55%, var(--border));
  color: var(--accent-bright); font-size: 13.5px;
}
.lab.done .lab-done, .interactive-stage.done .lab-done { display: flex; }
.lab-done .chk { font-family: 'JetBrains Mono', ui-monospace, monospace; font-weight: 600; }

/* ── buttons ──────────────────────────────────────── */
.btn {
  font-family: 'Noto Sans TC', Inter, sans-serif; font-size: 14px; font-weight: 500; line-height: 1;
  padding: 9px 16px; border-radius: var(--r-control); border: 1px solid var(--border-strong);
  background: var(--panel); color: var(--text); cursor: pointer;
  transition: border-color .15s, background .15s, transform .1s, color .15s;
  display: inline-flex; align-items: center; gap: 6px;
}
.btn:hover { border-color: var(--accent); color: var(--accent-bright); text-decoration: none; }
.btn:active { transform: translateY(1px); }
.btn:focus-visible { outline: none; box-shadow: var(--focus); }
.btn:disabled { opacity: .45; cursor: not-allowed; }
.btn:disabled:hover { border-color: var(--border-strong); color: var(--text); }
.btn-primary { background: var(--accent); border-color: var(--accent); color: #08101d; font-weight: 600; }
.btn-primary:hover { background: var(--accent-bright); border-color: var(--accent-bright); color: #08101d; }
.btn-ghost { background: transparent; border-color: transparent; color: var(--text-dim); }
.btn-ghost:hover { color: var(--accent-bright); border-color: var(--border); }
.btn-sm { font-size: 12.5px; padding: 7px 12px; }
.btn-row { display: flex; flex-wrap: wrap; gap: 8px; }

/* ── quiz ─────────────────────────────────────────── */
.quiz-block { display: grid; gap: 18px; }
.quiz-q { border: 1px solid var(--border); border-radius: var(--r-container); background: var(--panel); padding: 18px 20px; }
.quiz-q .qhead { display: flex; gap: 10px; align-items: baseline; margin-bottom: 14px; }
.quiz-q .qnum { font-family: 'JetBrains Mono', ui-monospace, monospace; font-size: 11px; letter-spacing: .1em; color: var(--accent); flex: none; }
.quiz-q .qtext { font-size: 16px; font-weight: 600; color: var(--text); line-height: 1.6; }
.quiz-opts { display: grid; gap: 8px; }
.quiz-opt {
  display: flex; gap: 12px; align-items: flex-start; width: 100%; text-align: left; padding: 11px 14px;
  border: 1px solid var(--border); border-radius: var(--r-control); background: var(--bg2); color: var(--text-dim);
  font-size: 14.5px; line-height: 1.55; cursor: pointer; font-family: inherit; transition: border-color .15s, background .15s, color .15s;
}
.quiz-opt:hover:not(:disabled) { border-color: var(--accent); color: var(--text); }
.quiz-opt:focus-visible { outline: none; box-shadow: var(--focus); }
.quiz-opt .mk { flex: none; font-family: 'JetBrains Mono', ui-monospace, monospace; font-size: 12px; color: var(--text-muted); width: 18px; }
.quiz-opt:disabled { cursor: default; }
.quiz-opt.correct { border-color: var(--good); background: var(--good-soft); color: var(--text); }
.quiz-opt.correct .mk { color: var(--good); }
.quiz-opt.wrong { border-color: var(--bad); background: var(--bad-soft); color: var(--text); }
.quiz-opt.wrong .mk { color: var(--bad); }
.quiz-explain { margin-top: 14px; padding: 12px 16px; border-radius: var(--r-control); background: var(--bg2); border-left: 3px solid var(--accent); font-size: 14px; color: var(--text-dim); line-height: 1.7; }
.quiz-explain b { color: var(--text); }
.quiz-explain .verdict { font-weight: 600; }
.quiz-explain .verdict.ok { color: var(--good); }
.quiz-explain .verdict.no { color: var(--bad); }
.quiz-score { margin-top: 4px; padding: 16px 20px; border: 1px solid var(--accent); border-radius: var(--r-container); background: var(--accent-soft); text-align: center; }
.quiz-score .big { font-family: 'Fraunces', Georgia, serif; font-size: 30px; font-weight: 700; color: var(--accent-bright); font-variant-numeric: tabular-nums; }
.quiz-score p { margin: 4px 0 0; color: var(--text-dim); font-size: 14px; }

/* ── chapter-nav ──────────────────────────────────── */
.chapter-nav {
  display: grid; grid-template-columns: 1fr auto 1fr; gap: 14px; align-items: stretch;
  margin: 66px 0 0; border-top: 1px solid var(--border); padding-top: 28px;
}
.chapter-nav a, .chapter-nav span.nav-empty {
  border: 1px solid var(--border); border-radius: var(--r-container); padding: 14px 18px;
  color: var(--text); transition: border-color .15s, transform .1s; display: flex; flex-direction: column; gap: 3px; justify-content: center;
}
.chapter-nav a:hover { border-color: var(--accent); transform: translateY(-2px); text-decoration: none; }
.chapter-nav .dir { font-family: 'JetBrains Mono', ui-monospace, monospace; font-size: 10px; letter-spacing: .14em; text-transform: uppercase; color: var(--text-muted); }
.chapter-nav .ttl { font-size: 14.5px; font-weight: 600; }
.chapter-nav a.next { text-align: right; align-items: flex-end; }
.chapter-nav a.toc { text-align: center; align-items: center; justify-content: center; color: var(--accent-bright); }
.chapter-nav span.nav-empty { border-style: dashed; opacity: .4; }

/* ── footer ───────────────────────────────────────── */
.site-footer { border-top: 1px solid var(--border); margin-top: 44px; }
.site-footer-in {
  max-width: 1100px; margin: 0 auto; padding: 22px 24px; display: flex; justify-content: space-between; flex-wrap: wrap; gap: 8px;
  font-family: 'JetBrains Mono', ui-monospace, monospace; font-size: 10px; letter-spacing: .14em; text-transform: uppercase; color: var(--text-muted);
}

/* ── index-only 元件 ──────────────────────────────── */
.home-hero { text-align: center; padding: 60px 0 24px; max-width: 680px; margin: 0 auto; }
.home-hero h1 { font-size: 46px; margin: 16px 0 18px; }
.home-hero .tagline { font-size: 18.5px; color: var(--text-dim); margin: 0 auto 12px; }
.home-hero .claim { font-size: 15.5px; color: var(--text-muted); max-width: 48ch; margin: 0 auto 26px; line-height: 1.75; }
.cta-row { display: flex; justify-content: center; gap: 10px; flex-wrap: wrap; }
.promo-band { text-align: center; font-family: 'JetBrains Mono', monospace; font-size: 11px; letter-spacing: .14em; text-transform: uppercase; color: var(--text-muted); margin-top: 24px; }

.what-cards { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; }
.what-card { border: 1px solid var(--border); border-radius: var(--r-container); background: var(--panel); padding: 22px 20px; }
.what-card .n { font-family: 'JetBrains Mono', ui-monospace, monospace; font-size: 11px; letter-spacing: .14em; color: var(--accent); }
.what-card .t { font-family: 'Fraunces', Georgia, serif; font-size: 20px; font-weight: 600; margin: 8px 0 8px; }
.what-card p { margin: 0; font-size: 14.5px; color: var(--text-dim); }

.level-section { margin: 46px 0; }
.level-section-head { display: flex; align-items: center; gap: 14px; margin: 0 0 20px; flex-wrap: wrap; }
.level-section-head .theme { font-family: 'Fraunces', Georgia, serif; font-size: 22px; font-weight: 600; color: var(--text); }
.level-section-head .line { height: 1px; flex: 1; min-width: 20px; background: var(--border); }

.chap-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 14px; }
.chap-card { display: block; border: 1px solid var(--border); border-radius: var(--r-container); background: var(--panel); padding: 16px 18px; color: inherit; transition: border-color .15s, transform .1s; }
.chap-card:hover { border-color: var(--accent); transform: translateY(-2px); text-decoration: none; }
.chap-card .cnum { font-family: 'JetBrains Mono', ui-monospace, monospace; font-size: 10.5px; letter-spacing: .1em; color: var(--text-muted); }
.chap-card .ctitle { font-size: 15.5px; font-weight: 650; color: var(--text); margin: 4px 0 5px; line-height: 1.4; }
.chap-card .cinter { font-size: 12.5px; color: var(--text-muted); font-family: 'JetBrains Mono', ui-monospace, monospace; letter-spacing: .02em; }
.chap-dots { display: flex; gap: 6px; margin-top: 12px; }
.chap-dots .dot { display: inline-flex; align-items: center; gap: 5px; font-family: 'JetBrains Mono', ui-monospace, monospace; font-size: 9.5px; letter-spacing: .08em; text-transform: uppercase; color: var(--text-muted); }
.chap-dots .dot::before { content: ""; width: 8px; height: 8px; border-radius: 50%; background: transparent; border: 1.5px solid var(--border-strong); }
.chap-dots .dot.on { color: var(--accent-bright); }
.chap-dots .dot.on::before { background: var(--accent); border-color: var(--accent); }

.xp-panel { border: 1px solid var(--border); border-radius: var(--r-container); background: linear-gradient(180deg, var(--panel-2), var(--panel)); padding: 24px 26px; }
.xp-panel .grid2 { align-items: start; }
.xp-stat { display: flex; align-items: baseline; gap: 8px; }
.xp-stat .v { font-family: 'Fraunces', Georgia, serif; font-size: 34px; font-weight: 700; color: var(--accent-bright); font-variant-numeric: tabular-nums; }
.xp-stat .k { font-size: 13px; color: var(--text-muted); }
.level-ladder { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 12px; }


/* ── 深化模組（v2）：統計史 / 案例檔案 / 審稿人 / 回呼 ── */
.history {
  background: var(--panel); border: 1px solid var(--border); border-left: 4px solid var(--violet);
  border-radius: var(--r-control); padding: 16px 18px 16px 20px; margin: 22px 0;
}
.history .t {
  font-family: 'JetBrains Mono', ui-monospace, monospace; font-size: 10.5px;
  letter-spacing: .14em; text-transform: uppercase; color: var(--violet); margin: 0 0 8px;
}
.history p { margin: 0; color: var(--text-dim); font-size: 15.5px; }
.history p + p { margin-top: 10px; }
.history b { color: var(--text); }

.casefile {
  background: linear-gradient(180deg, var(--panel-2), var(--panel));
  border: 1px solid var(--border-strong); border-radius: var(--r-container);
  padding: 18px 20px; margin: 24px 0;
}
.casefile .t {
  font-family: 'JetBrains Mono', ui-monospace, monospace; font-size: 10.5px;
  letter-spacing: .14em; text-transform: uppercase; color: var(--warn); margin: 0 0 10px;
}
.casefile p { margin: 8px 0 0; color: var(--text-dim); font-size: 15.5px; }
.casefile b { color: var(--text); }

.reviewer {
  background: var(--panel); border: 1px dashed var(--border-strong); border-radius: var(--r-container);
  padding: 18px 20px; margin: 24px 0;
}
.reviewer .t {
  font-family: 'JetBrains Mono', ui-monospace, monospace; font-size: 10.5px;
  letter-spacing: .14em; text-transform: uppercase; color: var(--info); margin: 0 0 10px;
}
.reviewer .claim {
  font-family: Inter, Georgia, serif; color: var(--text); font-size: 15.5px; line-height: 1.7;
  border-left: 2px solid var(--info); padding-left: 14px; margin: 0 0 12px;
}
.reviewer details { margin: 0; }
.reviewer summary {
  cursor: pointer; color: var(--accent-bright); font-size: 14px; font-weight: 500;
  padding: 8px 12px; border: 1px solid var(--border); border-radius: var(--r-control);
  display: inline-block; transition: border-color .15s;
  list-style: none;
}
.reviewer summary::-webkit-details-marker { display: none; }
.reviewer summary:hover { border-color: var(--accent); }
.reviewer summary:focus-visible { outline: none; box-shadow: var(--focus); }
.reviewer details[open] summary { color: var(--text-muted); border-color: var(--border); }
.reviewer details p { margin: 12px 0 0; color: var(--text-dim); font-size: 15px; }
.reviewer details b { color: var(--text); }

.recall {
  background: var(--accent-soft); border: 1px solid color-mix(in srgb, var(--accent) 35%, var(--border));
  border-radius: var(--r-control); padding: 14px 18px; margin: 22px 0;
}
.recall .t {
  font-family: 'JetBrains Mono', ui-monospace, monospace; font-size: 10.5px;
  letter-spacing: .14em; text-transform: uppercase; color: var(--accent); margin: 0 0 6px;
}
.recall p { margin: 0; color: var(--text); font-size: 15px; }
.recall details { display: inline; }
.recall summary { cursor: pointer; color: var(--accent-bright); display: inline; list-style: none; }
.recall summary::-webkit-details-marker { display: none; }

/* ── motion ───────────────────────────────────────── */
@keyframes rise { from { opacity: 0; transform: translateY(10px); } to { opacity: 1; transform: none; } }
.rise { animation: rise .5s ease both; }
@media (prefers-reduced-motion: reduce) {
  * { animation: none !important; transition: none !important; scroll-behavior: auto !important; }
}

/* ── responsive ───────────────────────────────────── */
@media (max-width: 720px) {
  body { font-size: 16px; }
  .container { padding: 0 18px 84px; }
  h1 { font-size: 32px; }
  .home-hero h1 { font-size: 34px; }
  h2 { font-size: 23px; }
  .grid2, .grid3, .what-cards, .chap-grid { grid-template-columns: 1fr; }
  .interactive-stage, .lab, .card, .plain, .xp-panel { padding-left: 15px; padding-right: 15px; }
  .lab-controls { gap: 12px; }
  .control { flex-basis: 100%; min-width: 0; }
  .chapter-nav { grid-template-columns: 1fr; }
  .chapter-nav a.next { text-align: left; align-items: flex-start; }
  .site-header-in { padding: 12px 18px; }
  .home-hero { padding-top: 40px; }
}

/* ── print / light fallback ───────────────────────── */
@media print {
  :root {
    --bg: #ffffff; --bg2: #f4f7fb; --panel: #ffffff; --panel-2: #f4f7fb; --stage: #f8fafc; --stage-2: #eef3f9;
    --border: #d8e0ea; --border-strong: #c2cdda;
    --text: #16202c; --text-dim: #48566a; --text-muted: #6b7788; --stage-text: #16202c;
    --accent: #2563eb; --accent-bright: #1d4ed8;
  }
  body { background: #fff; }
  .site-header, .chapter-nav, .lab-controls { break-inside: avoid; }
}

/* ============================================================
   國考 T1 實驗室 — 章末「接回其他資源」整合元件 + 閉書重建清單
   ============================================================ */
.integrate { border-top: 1px solid var(--border); padding-top: 8px; }
.linkgrid { display: grid; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); gap: 14px; margin-top: 14px; }
.linkcard {
  background: var(--panel); border: 1px solid var(--border); border-radius: 12px;
  padding: 16px 18px; display: flex; flex-direction: column; gap: 8px;
}
.linkcard .lk-tag {
  font-family: 'JetBrains Mono', monospace; font-size: 10.5px; letter-spacing: .12em;
  text-transform: uppercase; color: var(--text-muted);
}
.linkcard p { margin: 0; font-size: 14px; color: var(--text-dim); }
.linkcard a { color: var(--accent); text-decoration: none; font-size: 14.5px; font-weight: 600; }
.linkcard a:hover { color: var(--accent-bright); text-decoration: underline; }
.linkcard code { font-family: 'JetBrains Mono', monospace; font-size: 13px; color: var(--text-dim); }
.recall-list { margin: 8px 0 0; padding-left: 20px; color: var(--text-dim); }
.recall-list li { margin: 10px 0; line-height: 1.7; }