/* whetstone docs — shared styles for every page (tokens, base type, nav, footer, timeline, final CTA).
 * Page-specific styles stay inline in each page. Dark-only by design: the "whetstone" look is graphite + ember. */
/* ───────────────────────── tokens ───────────────────────── */
:root {
  color-scheme: dark;
  --bg: #0f1113;
  --bg-2: #13161a;
  --panel: #191d21;
  --panel-2: #20252a;
  --line: #2a3036;
  --line-2: #363d44;
  --text: #ece7de;
  --muted: #a2a7ac;
  --dim: #6e757c;

  --ember: #ff7a3d;
  --ember-2: #ffb06b;
  --refuse: #ff5d6c;
  --ok: #7ad48c;
  --warn: #f2c14e;

  --l1: #8f96ff;
  --l2: #3cc6a8;
  --l3: #e8b54d;
  --l4: #b9a48f;

  --serif: "Iowan Old Style", "Charter", "Palatino Linotype", "Georgia", "Songti SC", "Noto Serif SC", "Source Han Serif SC", serif;
  --sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans SC", system-ui, sans-serif;
  --mono: "SF Mono", "JetBrains Mono", ui-monospace, Menlo, Consolas, "PingFang SC", monospace;

  --gutter: clamp(18px, 4vw, 40px);
  --wrap: 1180px;
  --r: 14px;
  --grain: url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' width='180' height='180'><filter id='n'><feTurbulence type='fractalNoise' baseFrequency='.85' numOctaves='2' stitchTiles='stitch'/><feColorMatrix values='0 0 0 0 1 0 0 0 0 1 0 0 0 0 1 0 0 0 .55 0'/></filter><rect width='100%' height='100%' filter='url(%23n)'/></svg>");
}

/* ───────────────────────── base ───────────────────────── */
*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
body {
  margin: 0; background: var(--bg); color: var(--text);
  font: 16px/1.65 var(--sans); -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}
body::before {               /* stone grain over everything */
  content: ""; position: fixed; inset: 0; pointer-events: none; z-index: 100;
  background-image: var(--grain); opacity: .045; mix-blend-mode: overlay;
}
html[data-lang="en"] .zh { display: none !important; }
html[data-lang="zh"] .en { display: none !important; }
a { color: inherit; }
code, kbd, .mono { font-family: var(--mono); font-size: .9em; }
code { background: rgba(255,255,255,.06); padding: .1em .38em; border-radius: 5px; }
img, svg { max-width: 100%; }
[hidden] { display: none !important; }
:focus-visible { outline: 2px solid var(--ember); outline-offset: 3px; border-radius: 4px; }

.wrap { max-width: var(--wrap); margin: 0 auto; padding-inline: var(--gutter); }
section { position: relative; padding-block: clamp(72px, 10vw, 128px); }
section + section { border-top: 1px solid rgba(255,255,255,.04); }

.kicker {
  display: inline-flex; align-items: center; gap: 10px;
  font: 600 12px/1 var(--mono); letter-spacing: .14em; text-transform: uppercase; color: var(--ember-2);
}
.kicker::before { content: ""; width: 22px; height: 1px; background: currentColor; opacity: .7; }
html[data-lang="zh"] .kicker { letter-spacing: .08em; }
h1, h2, h3 { font-family: var(--serif); font-weight: 500; letter-spacing: -.015em; margin: 0; text-wrap: balance; }
h2 { font-size: clamp(32px, 4.6vw, 54px); line-height: 1.08; margin-top: 18px; max-width: 20ch; }
html[data-lang="zh"] h2 { max-width: 16em; letter-spacing: 0; line-height: 1.22; }
h3 { font-size: 22px; line-height: 1.25; }
.lede { color: var(--muted); font-size: clamp(16px, 1.6vw, 18.5px); max-width: 62ch; margin: 20px 0 0; }
.sec-head { margin-bottom: clamp(36px, 5vw, 60px); }
em.hl { font-style: normal; color: var(--ember); }

.btn {
  display: inline-flex; align-items: center; gap: 10px; text-decoration: none;
  font: 600 15px/1 var(--sans); padding: 14px 22px; border-radius: 999px;
  border: 1px solid transparent; transition: transform .2s, background .2s, border-color .2s, box-shadow .2s;
}
.btn--hot { background: var(--ember); color: #1a0d05; box-shadow: 0 0 0 0 rgba(255,122,61,.5), 0 10px 30px -10px rgba(255,122,61,.7); }
.btn--hot:hover { transform: translateY(-2px); box-shadow: 0 0 0 6px rgba(255,122,61,.14), 0 16px 34px -12px rgba(255,122,61,.8); }
.btn--ghost { border-color: var(--line-2); color: var(--text); }
.btn--ghost:hover { border-color: var(--muted); transform: translateY(-2px); }

/* reveal on scroll (only when JS is running) */
.js .rv { opacity: 0; transform: translateY(18px); transition: opacity .8s cubic-bezier(.2,.7,.2,1), transform .8s cubic-bezier(.2,.7,.2,1); }
.js .rv.in { opacity: 1; transform: none; }
.js .rv.d1 { transition-delay: .08s; } .js .rv.d2 { transition-delay: .16s; } .js .rv.d3 { transition-delay: .24s; } .js .rv.d4 { transition-delay: .32s; }

/* ───────────────────────── nav ───────────────────────── */
.nav {
  position: sticky; top: 0; z-index: 50;
  padding-top: env(safe-area-inset-top, 0px);
  background: rgba(15,17,19,.72); backdrop-filter: blur(14px) saturate(140%); -webkit-backdrop-filter: blur(14px) saturate(140%);
  border-bottom: 1px solid rgba(255,255,255,.06);
}
.nav .wrap { display: flex; align-items: center; gap: 28px; height: 64px; }
.brand { display: flex; align-items: center; gap: 10px; text-decoration: none; font: 600 16px/1 var(--sans); white-space: nowrap; }
.brand small { color: var(--dim); font-weight: 500; }
.nav-links { display: flex; gap: 20px; margin-left: auto; }
.nav-links a { text-decoration: none; color: var(--muted); font-size: 14px; transition: color .2s; white-space: nowrap; }
.nav-links a:hover { color: var(--text); }
.nav-links a[aria-current="page"] { color: var(--ember-2); }
.nav-act { display: flex; gap: 10px; align-items: center; }
.lang {
  background: transparent; color: var(--muted); border: 1px solid var(--line-2); border-radius: 999px;
  font: 600 12px/1 var(--mono); padding: 8px 12px; cursor: pointer; letter-spacing: .06em; white-space: nowrap;
}
.lang:hover { color: var(--text); border-color: var(--muted); }
.gh { display: inline-flex; align-items: center; gap: 8px; text-decoration: none; font: 600 13px/1 var(--sans);
  padding: 9px 14px; border-radius: 999px; background: var(--text); color: var(--bg); }
@media (max-width: 1080px) { .nav-links { display: none; } .nav-act { margin-left: auto; } }
@media (max-width: 480px) { .brand small { display: none; } .nav .wrap { gap: 12px; } }

.banner { border-bottom: 1px solid rgba(255,255,255,.05); background: linear-gradient(90deg, rgba(255,122,61,.10), transparent 60%); }
.banner .wrap { display: flex; gap: 12px; align-items: center; padding-block: 10px; font-size: 13.5px; color: var(--muted); flex-wrap: wrap; }
.banner b { color: var(--text); font-weight: 600; }
.tag { font: 700 10.5px/1 var(--mono); letter-spacing: .1em; padding: 5px 8px; border-radius: 6px; background: var(--ember); color: #1a0d05; }

/* ───────────────────────── scenario ───────────────────────── */
.tl-list { list-style: none; margin: 0; padding: 0; position: relative; max-width: 860px; }
.tl-list::before { content: ""; position: absolute; left: 21px; top: 10px; bottom: 10px; width: 2px; background: linear-gradient(var(--ember), var(--l2), var(--l1)); opacity: .5; }
.tl-list li { position: relative; display: grid; grid-template-columns: 44px 1fr; gap: 22px; padding-bottom: 34px; }
.tl-list li:last-child { padding-bottom: 0; }
.tl-list li > div { min-width: 0; }
.tl-list .k { width: 44px; height: 44px; border-radius: 50%; display: grid; place-items: center; background: var(--bg); border: 2px solid var(--ember); font: 600 15px/1 var(--mono); color: var(--ember-2); position: relative; z-index: 1; }
.tl-list h3 { font-size: 21px; padding-top: 8px; }
.tl-list p { margin: 8px 0 0; color: var(--muted); }

/* ───────────────────────── final + footer ───────────────────────── */
.final { text-align: center; overflow: hidden; }
.final::before { content: ""; position: absolute; left: 50%; top: 50%; width: 1000px; height: 600px; transform: translate(-50%, -50%); background: radial-gradient(closest-side, rgba(255,122,61,.14), transparent); pointer-events: none; }
.final h2 { margin: 18px auto 0; max-width: 16ch; font-size: clamp(40px, 6vw, 76px); position: relative; }
.final .lede { margin: 22px auto 0; position: relative; }
.final .cta { justify-content: center; position: relative; }
footer { border-top: 1px solid var(--line); padding-block: 48px calc(48px + env(safe-area-inset-bottom, 0px)); color: var(--dim); font-size: 13.5px; }
.foot { display: grid; grid-template-columns: 1.4fr repeat(3, 1fr); gap: 28px; }
.foot h5 { margin: 0 0 12px; font: 600 12px/1 var(--mono); letter-spacing: .1em; text-transform: uppercase; color: var(--muted); }
.foot a { display: block; text-decoration: none; padding: 4px 0; color: var(--dim); }
.foot a:hover { color: var(--text); }
.foot p { margin: 12px 0 0; max-width: 40ch; }
@media (max-width: 760px) { .foot { grid-template-columns: 1fr 1fr; } }

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { animation: none !important; transition: none !important; scroll-behavior: auto !important; }
}

/* ───────────────────────── sub-pages: header, prose, code, tables, cards ───────────────────────── */
.page-hero { padding-block: clamp(56px, 8vw, 104px) clamp(40px, 5vw, 64px); position: relative; overflow: hidden; }
.page-hero::before { content: ""; position: absolute; width: 760px; height: 760px; right: -240px; top: -300px; pointer-events: none; background: radial-gradient(closest-side, rgba(255,122,61,.13), transparent); }
.page-hero h1 { position: relative; font-size: clamp(38px, 5.4vw, 68px); line-height: 1.06; letter-spacing: -.025em; margin-top: 20px; max-width: 18ch; }
html[data-lang="zh"] .page-hero h1 { letter-spacing: 0; line-height: 1.2; max-width: 15em; }
.page-hero .lede { position: relative; }
.prose { max-width: 720px; }
.prose p { margin: 0 0 22px; font-size: 17.5px; line-height: 1.8; color: #d9d4cb; }
.prose h2 { font-size: clamp(26px, 3vw, 34px); margin: 64px 0 20px; max-width: none; }
.prose ul, .prose ol { margin: 0 0 22px; padding-left: 1.3em; font-size: 17px; line-height: 1.75; color: #d9d4cb; }
.prose li { margin-bottom: 10px; }
.prose strong, .prose b { color: var(--text); }
.pull { margin: 8px 0 28px; padding: 22px 26px; border-left: 3px solid var(--ember); background: linear-gradient(90deg, rgba(255,122,61,.10), transparent); border-radius: 0 12px 12px 0; font: 400 clamp(19px, 2vw, 23px)/1.5 var(--serif); color: var(--text); }
.note { font-size: 14.5px !important; color: var(--muted) !important; }
.codeblock { margin: 0 0 18px; background: #0b0d0f; border: 1px solid var(--line); border-radius: 14px; overflow: hidden; }
.codeblock .bar { display: flex; gap: 7px; align-items: center; padding: 11px 14px; background: #14171a; border-bottom: 1px solid var(--line); font: 12px/1 var(--mono); color: var(--dim); }
.codeblock .bar i { width: 10px; height: 10px; border-radius: 50%; background: #3a3f45; }
.codeblock .bar i:nth-child(1) { background: #ff6159; } .codeblock .bar i:nth-child(2) { background: #ffbd2e; } .codeblock .bar i:nth-child(3) { background: #28c941; }
.codeblock .bar span { margin-left: 8px; }
.codeblock pre { margin: 0; padding: 18px 20px; overflow-x: auto; font: 13px/1.75 var(--mono); color: #c9cdd1; }
.codeblock pre code { background: none; padding: 0; font-size: inherit; }
.codeblock .cm { color: var(--dim); } .codeblock .fl { color: var(--ember-2); } .codeblock .p { color: var(--ok); }
.codeblock .e { color: #ff8c97; } .codeblock .w { color: var(--warn); } .codeblock .s { color: var(--text); font-weight: 700; }
.tbl-wrap { overflow-x: auto; border: 1px solid var(--line); border-radius: 16px; background: var(--panel); }
.tbl { width: 100%; border-collapse: collapse; font-size: 15px; }
.tbl th, .tbl td { text-align: left; padding: 16px 18px; border-bottom: 1px solid var(--line); vertical-align: top; }
.tbl th { font: 600 11.5px/1.2 var(--mono); letter-spacing: .1em; text-transform: uppercase; color: var(--dim); }
html[data-lang="zh"] .tbl th { letter-spacing: .04em; }
.tbl tbody tr:last-child td { border-bottom: 0; }
.tbl td:not(.tag-lv) { color: #d9d4cb; }
.tag-lv { font: 700 13px/1 var(--mono); white-space: nowrap; }
.c-hi { color: var(--ok); } .c-md { color: #6fb3e0; } .c-lo { color: #8d939a; }
.c-l1 { color: var(--l1); } .c-l2 { color: var(--l2); } .c-l3 { color: var(--l3); } .c-l4 { color: var(--l4); } .c-em { color: var(--ember-2); }
figcaption.cap { margin-top: 12px; font-size: 13.5px; color: var(--dim); }
.cards { display: grid; grid-template-columns: repeat(auto-fit, minmax(260px, 1fr)); gap: 16px; }
.card { background: var(--panel); border: 1px solid var(--line); border-radius: 16px; padding: 24px; }
.card .k { font: 700 11.5px/1 var(--mono); letter-spacing: .12em; text-transform: uppercase; color: var(--cc, var(--ember-2)); }
html[data-lang="zh"] .card .k { letter-spacing: .04em; }
.card h3 { margin-top: 12px; font-size: 21px; }
.card p { margin: 10px 0 0; color: var(--muted); font-size: 14.5px; line-height: 1.65; }
.card .foot-l3 { display: block; margin-top: 14px; padding-top: 12px; border-top: 1px dashed var(--line-2); font: 12px/1.5 var(--mono); color: var(--l3); }
.callout { display: flex; gap: 16px; align-items: flex-start; padding: 22px 24px; border-radius: 16px; border: 1px solid rgba(255,122,61,.45); background: linear-gradient(90deg, rgba(255,122,61,.12), rgba(255,122,61,.03)); }
.callout b { color: var(--ember-2); }
.callout p { margin: 0; font-size: 16px; line-height: 1.7; }
.back { display: inline-flex; gap: 8px; color: var(--ember-2); text-underline-offset: 4px; margin-top: 32px; }

/* ───────────────────────── feature pages (routing / use-time check) ───────────────────────── */
.feat-tag { display: inline-flex; align-items: center; gap: 8px; font: 700 11.5px/1 var(--mono); letter-spacing: .12em; text-transform: uppercase; color: #1a0d05; background: var(--ember); padding: 7px 10px; border-radius: 6px; }
html[data-lang="zh"] .feat-tag { letter-spacing: .04em; }
.page-hero .cta { position: relative; display: flex; gap: 12px; flex-wrap: wrap; margin-top: 30px; }
.stats3 { display: grid; grid-template-columns: repeat(3, 1fr); border: 1px solid var(--line); border-radius: var(--r); background: rgba(25,29,33,.6); margin-top: 44px; position: relative; }
.stats3 > div { padding: 22px 24px; }
.stats3 > div + div { border-left: 1px solid var(--line); }
.stats3 b { display: block; font: 500 clamp(34px, 4vw, 50px)/1 var(--serif); letter-spacing: -.02em; color: var(--text); }
.stats3 b.hot { color: var(--ember); }
.stats3 span { display: block; margin-top: 10px; color: var(--muted); font-size: 13.5px; line-height: 1.5; }
@media (max-width: 720px) { .stats3 { grid-template-columns: 1fr; } .stats3 > div + div { border-left: 0; border-top: 1px solid var(--line); } }
.sec { padding-block: clamp(64px, 9vw, 112px); border-top: 1px solid rgba(255,255,255,.04); }
.sec.alt { background: var(--bg-2); }
.fig { margin: 0; background: var(--panel); border: 1px solid var(--line); border-radius: 20px; padding: clamp(18px, 3vw, 30px); }
.fig + .cap, .fig figcaption { margin-top: 14px; font-size: 13.5px; line-height: 1.6; color: var(--dim); max-width: 88ch; }
.pill { display: inline-flex; align-items: center; gap: 6px; font: 600 11px/1 var(--mono); padding: 5px 8px; border-radius: 999px; border: 1px solid var(--cc, var(--line-2)); color: var(--cc, var(--muted)); background: color-mix(in srgb, var(--cc, #fff) 12%, transparent); white-space: nowrap; }
.dot { display: inline-block; width: 8px; height: 8px; border-radius: 50%; background: var(--dc, var(--muted)); flex: none; }
.kcards { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; }
.kcard { display: flex; flex-direction: column; gap: 10px; background: var(--panel); border: 1px solid var(--line); border-radius: 16px; padding: 22px; }
.kcard .k { display: flex; align-items: center; gap: 8px; font: 700 11.5px/1.2 var(--mono); letter-spacing: .1em; text-transform: uppercase; color: var(--dc, var(--ember-2)); }
html[data-lang="zh"] .kcard .k { letter-spacing: .03em; }
.kcard h3 { font-size: 20px; }
.kcard p { margin: 0; color: var(--muted); font-size: 14.5px; line-height: 1.65; }
.kcard .act { margin-top: auto; padding-top: 12px; border-top: 1px dashed var(--line-2); color: var(--text); font-size: 13.5px; }
.kcard.muted { background: transparent; border-style: dashed; }
@media (max-width: 960px) { .kcards { grid-template-columns: repeat(2, 1fr); } }
@media (max-width: 640px) { .kcards { grid-template-columns: 1fr; } }
.split { display: grid; grid-template-columns: 2fr 3fr; gap: clamp(24px, 4vw, 48px); align-items: start; }
.split > * { min-width: 0; }
@media (max-width: 960px) { .split { grid-template-columns: 1fr; } }
.blist { list-style: none; margin: 22px 0 0; padding: 0; display: grid; gap: 14px; }
.blist li { position: relative; padding-left: 20px; color: #d9d4cb; font-size: 15.5px; line-height: 1.65; }
.blist li::before { content: ""; position: absolute; left: 0; top: 10px; width: 7px; height: 7px; border-radius: 2px; background: var(--ember); transform: rotate(45deg); }
.blist strong { color: var(--text); }
.term-out { margin: 0; background: #0b0d0f; border: 1px solid var(--line); border-radius: 14px; overflow: hidden; }
.term-out .bar { display: flex; gap: 7px; align-items: center; padding: 11px 14px; background: #14171a; border-bottom: 1px solid var(--line); }
.term-out .bar i { width: 10px; height: 10px; border-radius: 50%; background: #ff6159; } .term-out .bar i + i { background: #ffbd2e; } .term-out .bar i + i + i { background: #28c941; }
.term-out pre { margin: 0; padding: 18px 20px; font: 12.5px/1.7 var(--mono); color: #c9cdd1; white-space: pre-wrap; overflow-wrap: anywhere; }
.term-out code { background: none; padding: 0; font-size: inherit; }
.term-out .t-dim { color: var(--dim); } .term-out .t-hi { color: var(--ember-2); } .term-out .t-ok { color: var(--ok); font-weight: 600; }
.refs { display: grid; grid-template-columns: repeat(2, 1fr); gap: 16px; }
.ref { background: var(--panel); border: 1px solid var(--line); border-radius: 16px; padding: 22px 24px; }
.ref .no { font: 700 11px/1 var(--mono); letter-spacing: .12em; text-transform: uppercase; color: var(--rc, var(--ember-2)); }
html[data-lang="zh"] .ref .no { letter-spacing: .04em; }
.ref h3 { margin-top: 10px; font-size: 18px; }
.ref h3 a { text-decoration-color: var(--line-2); text-underline-offset: 4px; }
.ref h3 a:hover { text-decoration-color: var(--ember); }
.ref p { margin: 8px 0 0; color: var(--muted); font-size: 14.5px; line-height: 1.65; }
@media (max-width: 760px) { .refs { grid-template-columns: 1fr; } }
.caveat { max-width: 860px; border: 1px solid rgba(255,122,61,.4); border-radius: 20px; padding: clamp(22px, 3vw, 34px); background: linear-gradient(135deg, rgba(255,122,61,.10), transparent 60%); }
.caveat .kicker { margin-bottom: 4px; }
.caveat h3 { font-size: clamp(24px, 2.6vw, 30px); margin: 10px 0 16px; }
.caveat p { margin: 0 0 14px; color: #d9d4cb; font-size: 16px; line-height: 1.75; }
.caveat p:last-child { margin-bottom: 0; }
.details { max-width: 860px; }
.drow { display: grid; grid-template-columns: 170px 1fr; gap: 20px; padding: 18px 0; border-bottom: 1px solid var(--line); }
.drow:last-child { border-bottom: 0; }
.drow > span { font: 700 11.5px/1.6 var(--mono); letter-spacing: .1em; text-transform: uppercase; color: var(--ember-2); }
html[data-lang="zh"] .drow > span { letter-spacing: .04em; }
.drow p { margin: 0; color: #d9d4cb; font-size: 15.5px; line-height: 1.7; }
.drow code { white-space: nowrap; }
@media (max-width: 720px) { .drow { grid-template-columns: 1fr; gap: 6px; } }
.endcard { max-width: 860px; margin-top: 48px; padding: 28px; border-radius: 20px; border: 1px solid var(--line); background: linear-gradient(135deg, rgba(255,122,61,.10), var(--panel) 55%); }
.endcard p { margin: 0 0 18px; color: #d9d4cb; font-size: 16px; line-height: 1.7; }
.endcard .cta { display: flex; gap: 12px; flex-wrap: wrap; }
.quote { margin: 30px 0 0; padding: 0 0 0 24px; border-left: 3px solid var(--ember); }
.quote p { margin: 0; font: 400 clamp(21px, 2.4vw, 27px)/1.45 var(--serif); color: var(--text); }
.quote cite { display: block; margin-top: 12px; font-style: normal; font-size: 13.5px; color: var(--dim); }
.legend-row { display: flex; flex-wrap: wrap; gap: 8px 20px; margin-top: 16px; font-size: 12.5px; color: var(--muted); }
.legend-row span { display: inline-flex; align-items: center; gap: 8px; }
.js .grow { transform: scaleY(0); transform-origin: bottom; transition: transform 1s cubic-bezier(.2,.8,.2,1); }
.js .in .grow { transform: none; }
.js .growx { transform: scaleX(0); transform-origin: left; transition: transform 1.1s cubic-bezier(.2,.8,.2,1); }
.js .in .growx { transform: none; }