:root {
  --paper: #fbfaf6;
  --paper-2: #f3f1e9;
  --ink: #17212b;
  --muted: #65717d;
  --line: #d8d8d1;
  --blue: #1859a9;
  --blue-mist: #e6effa;
  --orange: #b95713;
  --orange-mist: #f9eadf;
  --green: #176b4a;
  --green-mist: #e2f2ea;
  --red: #ad302c;
  --red-mist: #f8e6e4;
  --violet: #6d42a1;
  --violet-mist: #eee7f7;
  --v1: #1859a9;
  --v2: #176b4a;
  --v3: #6d42a1;
  --v4: #b95713;
  --v5: #8b3b4d;
  --accent: var(--blue);
  --accent-mist: var(--blue-mist);
  --sans: Inter, ui-sans-serif, -apple-system, BlinkMacSystemFont, "Segoe UI", "Noto Sans SC", "PingFang SC", sans-serif;
  --mono: "SFMono-Regular", Consolas, "Liberation Mono", Menlo, monospace;
  color-scheme: light;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  color: var(--ink);
  background:
    linear-gradient(90deg, transparent 31px, rgba(24,89,169,.05) 32px, transparent 33px),
    var(--paper);
  font-family: var(--sans);
  line-height: 1.78;
  text-rendering: optimizeLegibility;
}
body[data-vol="1"] { --accent: var(--v1); --accent-mist: #e6effa; }
body[data-vol="2"] { --accent: var(--v2); --accent-mist: #e2f2ea; }
body[data-vol="3"] { --accent: var(--v3); --accent-mist: #eee7f7; }
body[data-vol="4"] { --accent: var(--v4); --accent-mist: #f9eadf; }
body[data-vol="5"] { --accent: var(--v5); --accent-mist: #f5e7eb; }

a { color: var(--blue); text-underline-offset: .2em; }
code, pre { font-family: var(--mono); }
code {
  padding: .12em .34em;
  border: 1px solid #d7dce2;
  border-radius: 4px;
  background: #f3f5f7;
  font-size: .9em;
}
strong { color: #0f1720; }

.content { padding: 88px 24px 72px; }
.wrap { width: min(900px, 100%); margin: 0 auto; }
.prose { width: min(760px, 100%); margin: 0 auto; }
.prose > p { margin: 1em 0; }
.prose h2 {
  margin: 2.25em 0 .72em;
  padding-bottom: .3em;
  border-bottom: 1px solid var(--line);
  font-size: clamp(1.28rem, 3vw, 1.65rem);
  line-height: 1.35;
}
.prose h3 { margin: 1.7em 0 .5em; font-size: 1.06rem; }
.prose ul, .prose ol { padding-left: 1.4em; }
.prose li + li { margin-top: .4em; }
.prose blockquote {
  margin: 1.3em 0;
  padding: .2em 0 .2em 1.15em;
  border-left: 4px solid var(--accent);
  color: #35414c;
}

/* 顶栏与「消息往返」进度线 */
.topbar {
  position: fixed;
  inset: 0 0 auto 0;
  z-index: 50;
  height: 62px;
  display: grid;
  grid-template-columns: auto minmax(120px, 1fr) auto auto;
  align-items: center;
  gap: 16px;
  padding: 0 max(18px, calc((100vw - 1080px) / 2));
  border-bottom: 1px solid rgba(23,33,43,.13);
  background: rgba(251,250,246,.94);
  backdrop-filter: blur(12px);
}
.brand { color: var(--ink); font-weight: 850; text-decoration: none; letter-spacing: .08em; }
.brand .mark { color: var(--accent); margin-right: .45em; }
.trk-wrap { min-width: 0; height: 30px; }
.trk-wrap svg { display: block; width: 100%; height: 30px; }
.trk-cell { fill: #e4e5e1; stroke: #d5d6d2; stroke-width: 1; }
.trk-cell.done { fill: #a9b3bc; stroke: #a9b3bc; }
.trk-base { stroke: #bcc2c6; stroke-width: 1; }
.ch-pos { color: var(--muted); font: 12px var(--mono); white-space: nowrap; }
.ch-pos b { color: var(--accent); }
.toc-btn, .close {
  border: 1px solid #cfd3d6;
  border-radius: 999px;
  background: white;
  color: var(--ink);
  padding: 7px 12px;
  font: 700 12px var(--sans);
  cursor: pointer;
}
.toc-btn:hover, .close:hover { border-color: var(--accent); color: var(--accent); }

/* 章节头 */
.chapter-head { width: min(760px, 100%); margin: 0 auto 42px; }
.kicker { color: var(--accent); font: 750 12px/1.4 var(--mono); letter-spacing: .12em; text-transform: uppercase; }
.chapter-head h1 {
  margin: .3em 0 .25em;
  max-width: 18em;
  font-size: clamp(2.25rem, 7vw, 4.25rem);
  line-height: 1.07;
  letter-spacing: -.055em;
}
.chapter-head h1 em { color: var(--accent); font-style: normal; }
.lede { max-width: 42em; color: #44515d; font-size: 1.15rem; }
.tags { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 18px; }
.tags span {
  padding: 4px 9px;
  border: 1px solid color-mix(in srgb, var(--accent) 28%, white);
  border-radius: 4px;
  background: var(--accent-mist);
  color: var(--accent);
  font: 700 11px var(--mono);
}
.relay {
  display: grid;
  grid-template-columns: repeat(7, 1fr);
  gap: 3px;
  margin: 26px 0 0;
}
.relay span { height: 7px; border-radius: 99px; background: #e3e5e4; }
.relay span.on { background: var(--accent); }

/* 固定栏目 */
.co, .lab, .takeaway {
  margin: 1.55em 0;
  padding: 18px 20px;
  border: 1px solid var(--line);
  border-left-width: 5px;
  border-radius: 7px;
  background: white;
}
.co p:first-of-type, .lab p:first-of-type { margin-top: .55em; }
.co p:last-child, .lab p:last-child { margin-bottom: 0; }
.co-t, .lab-title { font: 850 12px/1.4 var(--mono); letter-spacing: .045em; }
.predict { border-left-color: var(--orange); background: var(--orange-mist); }
.predict .co-t { color: var(--orange); }
.real { border-left-color: var(--green); background: var(--green-mist); }
.real .co-t { color: var(--green); }
.wrong { border-left-color: var(--red); background: var(--red-mist); }
.wrong .co-t { color: var(--red); }
.settle { border-left-color: var(--violet); background: var(--violet-mist); }
.settle .co-t { color: var(--violet); }
.bad, .good { display: block; padding-left: 1.55em; position: relative; }
.bad::before, .good::before { position: absolute; left: 0; font-weight: 900; }
.bad::before { content: "×"; color: var(--red); }
.good::before { content: "✓"; color: var(--green); }
.lab { border-left-color: var(--accent); background: #f7f8f9; }
.lab-title { color: var(--accent); }
.run { color: var(--muted); font-size: .92rem; }
.run a { font-weight: 700; }
.takeaway { border-left-color: var(--ink); background: #eef1f3; font-weight: 750; }
.interview {
  display: grid;
  grid-template-columns: 112px 1fr;
  gap: 12px;
  align-items: start;
  margin: 1.25em 0;
  padding: 14px 16px;
  border: 1px dashed #b9bec3;
  border-radius: 6px;
  background: #fff;
}
.interview b { color: var(--accent); font: 800 12px/1.5 var(--mono); }

/* 代码 */
pre {
  position: relative;
  overflow: auto;
  margin: 1.25em 0;
  padding: 20px 18px 17px;
  border: 1px solid #d5d9dc;
  border-radius: 7px;
  background: #f4f5f6;
  color: #1d2730;
  font-size: 13px;
  line-height: 1.62;
  tab-size: 2;
  white-space: pre;
}
pre.out { background: #eef2f4; }
pre.manifest { background: #f4f0f8; }
pre.gradle { background: #eef5f0; }
.tag-corner {
  position: absolute;
  top: 5px;
  right: 8px;
  color: #7c8791;
  font: 700 9px var(--mono);
  text-transform: uppercase;
  letter-spacing: .09em;
}
.tk-co { color: #72808c; font-style: italic; }
.tk-kw { color: #7040a0; font-weight: 750; }
.tk-st { color: #176b4a; }
.tk-fn { color: #1859a9; }
.tk-ty { color: #9a4b0f; font-weight: 700; }
.tk-nu { color: #a63131; }
.tk-an { color: #8b3b4d; font-weight: 700; }
.ook { color: var(--green); }
.oerr { color: var(--red); }
.odim { color: #7b8790; }

.table-scroll { overflow-x: auto; margin: 1.25em 0; }
table { width: 100%; border-collapse: collapse; font-size: .93rem; }
th, td { padding: 10px 12px; border: 1px solid var(--line); text-align: left; vertical-align: top; }
th { background: #eceeea; font-weight: 800; }
td code { white-space: nowrap; }

/* 首页 */
.home .content { padding-top: 42px; }
.hero { padding: 60px 0 44px; border-bottom: 1px solid var(--line); }
.eyebrow { color: var(--blue); font: 800 12px var(--mono); letter-spacing: .13em; }
.hero h1 { margin: .12em 0 0; font-size: clamp(5rem, 17vw, 9rem); line-height: .92; letter-spacing: -.1em; }
.hero h1 .sig { color: var(--orange); }
.en { margin: 10px 0 28px; color: var(--muted); font: 750 12px var(--mono); letter-spacing: .46em; }
.pitch { max-width: 48em; font-size: clamp(1.05rem, 2.5vw, 1.3rem); }
.hero-route {
  margin: 34px 0 24px;
  padding: 20px;
  border: 1px solid var(--line);
  border-radius: 9px;
  background: white;
}
.hero-route svg { display: block; width: 100%; height: auto; }
.meta-row { display: flex; flex-wrap: wrap; gap: 8px; }
.meta-row span { padding: 5px 9px; border-radius: 4px; background: #e9ecee; color: #53606a; font: 700 11px var(--mono); }
.meta-row b { color: var(--blue); }
.lens-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1px;
  margin: 1.4em 0;
  border: 1px solid var(--line);
  background: var(--line);
}
.lens-grid > div { padding: 14px 16px; background: white; }
.lens-grid .old { color: var(--red); }
.lens-grid .new { color: var(--green); font-weight: 750; }
.lens-grid small { display: block; margin-bottom: 4px; color: var(--muted); font: 700 10px var(--mono); }
.audience {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
  margin: 1.5em 0;
}
.audience > div { padding: 18px; border: 1px solid var(--line); border-radius: 7px; background: white; }
.audience h3 { margin-top: 0; }
.vol-block { margin: 2.4em 0; border-top: 5px solid var(--vc); }
.vh { display: flex; align-items: baseline; gap: 13px; padding: 13px 0 5px; }
.vh .vno { color: var(--vc); font: 850 11px var(--mono); }
.vh h2 { margin: 0; border: 0; font-size: 1.55rem; }
.vh .ven { margin-left: auto; color: #8a949c; font: 700 10px var(--mono); letter-spacing: .16em; }
.vd { margin-top: 0; color: var(--muted); }
.chs { padding: 0 !important; list-style: none; border-top: 1px solid var(--line); }
.chs li { margin: 0 !important; border-bottom: 1px solid var(--line); }
.chs a {
  display: grid;
  grid-template-columns: 44px 1fr auto;
  gap: 12px;
  align-items: center;
  padding: 13px 8px;
  color: var(--ink);
  text-decoration: none;
}
.chs a:hover { background: color-mix(in srgb, var(--vc) 7%, white); }
.chs .no { color: var(--vc); font: 800 12px var(--mono); }
.ct2 b, .ct2 em { display: block; }
.ct2 em { margin-top: 2px; color: var(--muted); font-size: .85rem; font-style: normal; }
.demo-tag { color: var(--vc); font: 700 10px var(--mono); white-space: nowrap; }
.source-note { color: var(--muted); font-size: .87rem; }

/* 全屏目录 */
.toc-overlay {
  position: fixed;
  inset: 0;
  z-index: 100;
  display: none;
  overflow: auto;
  padding: 28px;
  background: rgba(22,29,35,.38);
}
.toc-overlay.open { display: block; }
.toc-inner { width: min(820px, 100%); margin: 0 auto; padding: 24px; border-radius: 10px; background: var(--paper); box-shadow: 0 20px 70px rgba(0,0,0,.2); }
.toc-head { display: flex; justify-content: space-between; align-items: center; gap: 16px; }
.toc-head h2 { margin: 0; font-size: 2rem; }
.toc-sub { margin: .35em 0 1.3em; color: var(--muted); }
.toc-vol { margin-top: 22px; border-top: 4px solid var(--vc); }
.vol-name { padding-top: 8px; color: var(--vc); font-weight: 850; }
.vol-desc { color: var(--muted); font-size: .88rem; }
.toc-vol ol { padding: 0; list-style: none; }
.toc-vol li { border-top: 1px solid var(--line); }
.toc-vol a { display: grid; grid-template-columns: 38px 1fr auto; gap: 10px; padding: 9px 5px; color: var(--ink); text-decoration: none; }
.toc-vol a:hover, .toc-vol a.cur { background: color-mix(in srgb, var(--vc) 9%, white); }
.toc-vol .no { color: var(--vc); font: 700 11px var(--mono); }

.pager { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; width: min(760px, 100%); margin: 58px auto 0; }
.pager a { min-height: 88px; padding: 15px; border: 1px solid var(--line); border-radius: 7px; background: white; color: var(--ink); text-decoration: none; }
.pager a:hover { border-color: var(--accent); }
.pager .next { text-align: right; }
.pager .dir { display: block; color: var(--accent); font: 800 11px var(--mono); }
.pager .t { display: block; margin-top: 5px; font-weight: 750; }
.pager .none { visibility: hidden; }
.foot { width: min(760px, 100%); margin: 28px auto 0; padding-top: 18px; border-top: 1px solid var(--line); color: var(--muted); font-size: .82rem; }

@media (max-width: 720px) {
  .content { padding: 78px 17px 54px; }
  .topbar { grid-template-columns: auto 1fr auto; gap: 9px; padding: 0 12px; }
  .ch-pos { display: none; }
  .relay { grid-template-columns: repeat(7, 1fr); }
  .lens-grid, .audience { grid-template-columns: 1fr; }
  .interview { grid-template-columns: 1fr; gap: 3px; }
  .chs a { grid-template-columns: 34px 1fr; }
  .chs .demo-tag { grid-column: 2; }
  .toc-overlay { padding: 10px; }
  .toc-inner { padding: 18px 14px; }
  .toc-vol a { grid-template-columns: 30px 1fr; }
  .toc-vol .demo-tag { display: none; }
  .pager { grid-template-columns: 1fr; }
  .pager .next { text-align: left; }
  pre { margin-left: -6px; margin-right: -6px; font-size: 12px; }
}

@media print {
  .topbar, .toc-overlay, .pager { display: none !important; }
  body { background: white; }
  .content { padding-top: 24px; }
  .co, .lab, pre { break-inside: avoid; }
}