/* m683 Speech Lab · shared design system (tokens + layout + components). No external fonts or CDNs. */
:root{
  --ink:#14232b;--mute:#566870;--line:#dfe6e3;--bg:#f6f7f3;--card:#ffffff;--field:#ffffff;--field-line:#c9d5d0;
  --acc:#0f6d63;--acc-ink:#ffffff;--acc2:#e6f2ec;--acc3:#123c3a;--acc3-ink:#eef6f1;--acc3-mute:#c6ddd4;
  --warn:#9a4d12;--ok:#17703f;--bad:#a3341b;--hi:#ffe7a3;--hi-ink:#14232b;--note:#fbf6e8;--note-line:#eadfbd;--soft:#f1f5f2;
  --sky:#2f5f8a;--sky2:#e8f0f8;--focus:#d29b2c;
  --r:14px;--shadow:0 1px 2px rgba(20,35,43,.06),0 6px 24px rgba(20,35,43,.05);
  color-scheme:light;
}
@media (prefers-color-scheme:dark){:root:not([data-theme="light"]){
  --ink:#e7eeeb;--mute:#9db0aa;--line:#2a3a39;--bg:#0f1716;--card:#152120;--field:#0f1918;--field-line:#36504c;
  --acc:#4fb8a6;--acc-ink:#05211d;--acc2:#183330;--acc3:#0b2a28;--acc3-ink:#e6f4ef;--acc3-mute:#a9cbc0;
  --warn:#e8a46a;--ok:#6fd39a;--bad:#ff8a73;--hi:#6b5414;--hi-ink:#fff4cf;--note:#2a2516;--note-line:#4a4126;--soft:#132120;
  --sky:#8db8e3;--sky2:#14243a;--focus:#f0c060;--shadow:none;color-scheme:dark;
}}
:root[data-theme="dark"]{
  --ink:#e7eeeb;--mute:#9db0aa;--line:#2a3a39;--bg:#0f1716;--card:#152120;--field:#0f1918;--field-line:#36504c;
  --acc:#4fb8a6;--acc-ink:#05211d;--acc2:#183330;--acc3:#0b2a28;--acc3-ink:#e6f4ef;--acc3-mute:#a9cbc0;
  --warn:#e8a46a;--ok:#6fd39a;--bad:#ff8a73;--hi:#6b5414;--hi-ink:#fff4cf;--note:#2a2516;--note-line:#4a4126;--soft:#132120;
  --sky:#8db8e3;--sky2:#14243a;--focus:#f0c060;--shadow:none;color-scheme:dark;
}
*{box-sizing:border-box}
html{-webkit-text-size-adjust:100%}
body{margin:0;font:16px/1.6 system-ui,-apple-system,"Segoe UI",Roboto,"PingFang SC","Noto Sans CJK SC","Microsoft YaHei",sans-serif;color:var(--ink);background:var(--bg)}
a{color:var(--acc)}a:hover{text-decoration-thickness:2px}
img,svg{max-width:100%;height:auto}
:focus-visible{outline:3px solid var(--focus);outline-offset:2px}
.skip{position:absolute;left:12px;top:-60px;background:var(--card);color:var(--ink);padding:8px 12px;z-index:9;border-radius:8px}.skip:focus{top:10px}
.sr{position:absolute;width:1px;height:1px;overflow:hidden;clip:rect(0 0 0 0);white-space:nowrap}

/* nav */
.site-nav{max-width:1080px;margin:0 auto;padding:14px 16px;display:flex;gap:12px;align-items:center;justify-content:space-between;flex-wrap:wrap}
.brand{display:flex;gap:10px;align-items:center;font-size:19px;color:var(--ink);text-decoration:none;font-weight:650}
.mark{display:inline-flex;gap:3px;align-items:center;height:26px}.mark i{display:block;width:4px;border-radius:3px;background:var(--acc)}
.mark i:nth-child(1){height:9px}.mark i:nth-child(2){height:20px}.mark i:nth-child(3){height:26px}.mark i:nth-child(4){height:13px}
.site-nav ul{list-style:none;margin:0;padding:0;display:flex;gap:4px;flex-wrap:wrap}
.site-nav ul a{display:inline-block;padding:8px 10px;border-radius:8px;color:var(--mute);text-decoration:none;font-size:15px}
.site-nav ul a:hover,.site-nav ul a[aria-current="page"]{background:var(--acc2);color:var(--acc)}

/* layout */
main{max-width:1080px;margin:0 auto;padding:0 16px 48px}
.narrow{max-width:760px}
section{margin:28px 0}
h1{font-size:clamp(30px,5.2vw,52px);line-height:1.08;letter-spacing:-.02em;margin:18px 0 12px}
h1 em,h2 em{font-style:normal;color:var(--acc)}
h2{font-size:clamp(22px,3vw,30px);line-height:1.2;margin:0 0 12px;letter-spacing:-.01em}
h3{font-size:18px;margin:0 0 6px}
.lead{font-size:clamp(17px,2.1vw,20px);color:var(--mute);max-width:720px}
.eyebrow{font-size:13px;letter-spacing:.08em;text-transform:uppercase;color:var(--acc);font-weight:700;margin:0}
.muted,.small{color:var(--mute)}.small{font-size:14px}
.grid{display:grid;gap:16px}
.g2{grid-template-columns:repeat(2,minmax(0,1fr))}.g3{grid-template-columns:repeat(3,minmax(0,1fr))}.g4{grid-template-columns:repeat(4,minmax(0,1fr))}
@media (max-width:860px){.g3,.g4{grid-template-columns:repeat(2,minmax(0,1fr))}}
@media (max-width:620px){.g2,.g3,.g4{grid-template-columns:1fr}}

/* components */
.card{background:var(--card);border:1px solid var(--line);border-radius:var(--r);padding:20px;box-shadow:var(--shadow);min-width:0}
.card.dark{background:var(--acc3);color:var(--acc3-ink);border-color:var(--acc3)}.card.dark p,.card.dark li{color:var(--acc3-mute)}.card.dark a{color:var(--acc3-ink)}
.card.soft{background:var(--soft);box-shadow:none}
.card h3 .tag{margin-left:6px}
.btn{font:inherit;font-size:15px;border:1px solid var(--field-line);background:var(--card);color:var(--ink);border-radius:10px;padding:10px 16px;cursor:pointer;min-height:44px;display:inline-flex;align-items:center;gap:8px;text-decoration:none}
.btn.primary{background:var(--acc);border-color:var(--acc);color:var(--acc-ink)}
.btn.ghost{border-color:transparent;background:transparent;color:var(--acc)}
.btn:disabled{opacity:.45;cursor:default}
.row{display:flex;gap:12px;align-items:center;flex-wrap:wrap}
.tag{display:inline-block;font-size:12px;font-weight:650;padding:3px 8px;border-radius:999px;background:var(--acc2);color:var(--acc);vertical-align:middle}
.tag.sky{background:var(--sky2);color:var(--sky)}.tag.warn{background:var(--note);color:var(--warn)}
.note{background:var(--note);border:1px solid var(--note-line);border-radius:10px;padding:12px 14px;font-size:15px}
.ticks{list-style:none;padding:0;margin:8px 0}.ticks li{padding-left:26px;position:relative;margin:6px 0}
.ticks li::before{content:"";position:absolute;left:4px;top:.55em;width:10px;height:6px;border-left:2px solid var(--acc);border-bottom:2px solid var(--acc);transform:rotate(-45deg)}
.crosses li::before{border:0;width:12px;height:2px;background:var(--bad);transform:none;top:.75em}
table{width:100%;border-collapse:collapse;font-size:15px}td,th{text-align:left;border-bottom:1px solid var(--line);padding:9px 8px;vertical-align:top}th{font-size:13px;color:var(--mute);font-weight:650}
.tablewrap{overflow-x:auto}
.kpi{font-size:34px;font-weight:700;font-variant-numeric:tabular-nums;line-height:1.1}
.steps{counter-reset:s;list-style:none;padding:0;margin:0}.steps>li{counter-increment:s;position:relative;padding:0 0 18px 46px}
.steps>li::before{content:counter(s);position:absolute;left:0;top:0;width:32px;height:32px;border-radius:50%;background:var(--acc2);color:var(--acc);display:flex;align-items:center;justify-content:center;font-weight:700}
.timeline{list-style:none;padding:0;margin:0;border-left:2px solid var(--line)}.timeline li{position:relative;padding:0 0 16px 20px}
.timeline li::before{content:"";position:absolute;left:-7px;top:.45em;width:12px;height:12px;border-radius:50%;background:var(--card);border:2px solid var(--acc)}
.timeline li.hot::before{background:var(--warn);border-color:var(--warn)}
.timeline time{font-weight:700;font-variant-numeric:tabular-nums}
details{border:1px solid var(--line);border-radius:10px;padding:10px 14px;background:var(--card);margin:8px 0}summary{cursor:pointer;font-weight:650}
code,kbd,pre{font-family:ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;font-size:.92em}
pre{background:var(--soft);border:1px solid var(--line);border-radius:10px;padding:12px;overflow-x:auto}
.hero{padding:16px 0 8px}
.cta{display:flex;gap:12px;flex-wrap:wrap;margin-top:18px}
footer.site{max-width:1080px;margin:0 auto;padding:24px 16px 40px;color:var(--mute);font-size:14px;border-top:1px solid var(--line)}
footer.site a{color:var(--mute)}
.theme-toggle{font-size:13px}
@media print{.site-nav,footer.site,.noprint{display:none!important}body{background:#fff;color:#000}.card{box-shadow:none;break-inside:avoid}}
@media (prefers-reduced-motion:reduce){*{transition:none!important;animation:none!important;scroll-behavior:auto!important}}

/* airplane parts diagram */
.plane{width:100%;max-width:760px;display:block;margin:0 auto}
.plane .body{fill:var(--acc2);stroke:var(--acc);stroke-width:2}
.plane .wing{fill:var(--soft);stroke:var(--acc);stroke-width:2}
.plane .engine{fill:var(--acc);stroke:none}
.plane .part{fill:var(--card);stroke:var(--acc);stroke-width:2}
.plane .dot{fill:var(--acc)}.plane .dot-t{fill:var(--acc-ink);font:700 15px system-ui,sans-serif;text-anchor:middle;dominant-baseline:central}
.plane .lbl{fill:var(--ink);font:600 14px system-ui,sans-serif}
.plane .sub{fill:var(--mute);font:13px system-ui,sans-serif}
.plane .lead{stroke:var(--mute);stroke-width:1;stroke-dasharray:3 3;fill:none}
.parts{counter-reset:p;list-style:none;padding:0;margin:0;display:grid;gap:10px;grid-template-columns:repeat(2,minmax(0,1fr))}
.parts li{counter-increment:p;position:relative;padding:10px 12px 10px 48px;border:1px solid var(--line);border-radius:10px;background:var(--card)}
.parts li::before{content:counter(p);position:absolute;left:12px;top:10px;width:26px;height:26px;border-radius:50%;background:var(--acc);color:var(--acc-ink);display:flex;align-items:center;justify-content:center;font-weight:700;font-size:14px}
@media (max-width:620px){.parts{grid-template-columns:1fr}}
.line-card{display:flex;flex-direction:column;gap:8px}
.line-card .cta{margin-top:auto}
.bignum{font-size:13px;font-weight:700;letter-spacing:.06em;color:var(--mute);text-transform:uppercase}
.mt{margin-top:16px}.mt0{margin-top:0}