:root{--bg:#0d1117;--card:#161b22;--line:#30363d;--fg:#e6edf3;--mut:#8b949e;--acc:#2f81f7;--ok:#3fb950;--bad:#f85149;--warn:#d29922}
*{box-sizing:border-box}body{margin:0;background:var(--bg);color:var(--fg);font:15px/1.55 -apple-system,Segoe UI,Roboto,"PingFang SC","Microsoft YaHei",sans-serif}
a{color:var(--acc)}header{display:flex;align-items:center;gap:14px;padding:12px 20px;border-bottom:1px solid var(--line);background:#010409;position:sticky;top:0;z-index:5}
header .brand{font-weight:700;font-size:17px;color:var(--fg);text-decoration:none}header nav{display:flex;gap:14px;flex-wrap:wrap;flex:1}header nav a{color:var(--mut);text-decoration:none;font-size:14px}header nav a:hover{color:var(--fg)}
#langBtn{background:none;border:1px solid var(--line);color:var(--fg);border-radius:6px;padding:4px 10px;cursor:pointer}
main{max-width:1060px;margin:0 auto;padding:24px 18px 40px}h1{font-size:30px;margin:10px 0 8px}h2{font-size:21px;margin:30px 0 10px}h3{font-size:16px;margin:16px 0 6px}
.lead{color:var(--mut);font-size:17px;max-width:780px}.card{background:var(--card);border:1px solid var(--line);border-radius:10px;padding:16px 18px;margin:12px 0}
.grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(230px,1fr));gap:12px}.step{background:var(--card);border:1px solid var(--line);border-radius:10px;padding:14px}
.step b{display:block;color:var(--acc);font-size:13px;margin-bottom:4px}label{display:block;font-size:13px;color:var(--mut);margin:10px 0 4px}
input,select,textarea{width:100%;background:#0d1117;border:1px solid var(--line);color:var(--fg);border-radius:6px;padding:8px 10px;font:inherit}textarea{min-height:80px}
.row{display:grid;grid-template-columns:1fr 1fr;gap:12px}@media(max-width:700px){.row{grid-template-columns:1fr}h1{font-size:24px}header nav{display:none}}
button,.btn{background:var(--acc);color:#fff;border:0;border-radius:6px;padding:9px 16px;font:inherit;cursor:pointer;text-decoration:none;display:inline-block;margin:6px 6px 0 0}
button.sec{background:#21262d;border:1px solid var(--line)}button:disabled{opacity:.45;cursor:not-allowed}.mut{color:var(--mut)}.small{font-size:13px}
.ok{color:var(--ok)}.bad{color:var(--bad)}.warn{color:var(--warn)}.pill{display:inline-block;border-radius:999px;padding:1px 10px;font-size:12px;border:1px solid var(--line)}
.pill.ok{border-color:var(--ok)}.pill.bad{border-color:var(--bad)}.pill.warn{border-color:var(--warn)}code,.mono{font-family:ui-monospace,Menlo,Consolas,monospace;font-size:13px;word-break:break-all}
table{width:100%;border-collapse:collapse;font-size:14px}th,td{text-align:left;border-bottom:1px solid var(--line);padding:7px 6px;vertical-align:top}th{color:var(--mut);font-weight:600}
.msg{padding:10px 12px;border-radius:8px;margin:10px 0;border:1px solid var(--line);white-space:pre-wrap}.msg.ok{border-color:var(--ok);background:#3fb95014}.msg.bad{border-color:var(--bad);background:#f8514914}.msg.warn{border-color:var(--warn);background:#d2992214}
.tl{list-style:none;padding:0;margin:0}.tl li{padding:6px 0 6px 18px;border-left:2px solid var(--line);position:relative}.tl li:before{content:"";position:absolute;left:-6px;top:12px;width:10px;height:10px;border-radius:50%;background:var(--acc)}
.prog{display:flex;flex-wrap:wrap;gap:6px;margin:10px 0}.prog span{flex:1;min-width:120px;font-size:12px;padding:6px 8px;border-radius:6px;background:#21262d;border:1px solid var(--line);color:var(--mut)}.prog span.done{border-color:var(--ok);color:var(--ok)}.prog span.cur{border-color:var(--acc);color:var(--fg)}
footer{border-top:1px solid var(--line);color:var(--mut);font-size:13px;padding:18px 20px 28px;text-align:center}footer p{margin:4px auto;max-width:900px}
.hide{display:none!important}@media print{header,footer .links,.noprint{display:none!important}body{background:#fff;color:#000}.card{border-color:#999;background:#fff}a{color:#000}th,td{border-color:#999}.mut{color:#444}}
/* ---------- landing ---------- */
.lp main{max-width:none;padding:0}.wrap{max-width:1120px;margin:0 auto;padding:0 20px}
.hero{background:radial-gradient(1200px 500px at 15% -10%,#1f6feb55,transparent 60%),radial-gradient(900px 500px at 95% 10%,#8957e533,transparent 60%),#0d1117;border-bottom:1px solid var(--line);padding:70px 0 60px}
.hero .eyebrow{display:inline-block;font-size:13px;letter-spacing:.3px;color:#a5d6ff;border:1px solid #1f6feb88;background:#1f6feb1f;border-radius:999px;padding:4px 12px;margin-bottom:18px}
.hero h1{font-size:46px;line-height:1.12;margin:0 0 16px;max-width:820px;letter-spacing:-.5px}.hero p.sub{font-size:19px;color:#c9d1d9;max-width:720px;margin:0 0 26px}
.hero .btn{padding:13px 26px;font-size:16px;border-radius:8px;font-weight:600}.btn.ghost{background:transparent;border:1px solid var(--line);color:var(--fg)}
.trust{display:flex;flex-wrap:wrap;gap:10px 22px;margin-top:30px;color:var(--mut);font-size:13px}.trust span:before{content:"✓ ";color:var(--ok)}
.sec2{padding:64px 0;border-bottom:1px solid var(--line)}.sec2.alt{background:#0b0f15}.sec2 h2{font-size:32px;margin:0 0 10px;letter-spacing:-.3px}.sec2 .intro{color:var(--mut);font-size:17px;max-width:720px;margin:0 0 32px}
.cards{display:grid;grid-template-columns:repeat(auto-fit,minmax(240px,1fr));gap:16px}.cardx{background:var(--card);border:1px solid var(--line);border-radius:14px;padding:22px;transition:border-color .2s,transform .2s}.cardx:hover{border-color:#1f6feb;transform:translateY(-2px)}
.cardx h3{margin:12px 0 8px;font-size:18px}.cardx p{margin:0;color:#c9d1d9;font-size:15px}.ico{width:42px;height:42px;border-radius:10px;display:flex;align-items:center;justify-content:center;background:#1f6feb22;border:1px solid #1f6feb66}.ico svg{width:22px;height:22px;stroke:#58a6ff;fill:none;stroke-width:2;stroke-linecap:round;stroke-linejoin:round}
.steps4{display:grid;grid-template-columns:repeat(auto-fit,minmax(220px,1fr));gap:16px;counter-reset:s}.steps4 div{position:relative;background:var(--card);border:1px solid var(--line);border-radius:14px;padding:22px 20px 20px}.steps4 div:before{counter-increment:s;content:counter(s);display:flex;align-items:center;justify-content:center;width:34px;height:34px;border-radius:50%;background:linear-gradient(135deg,#2f81f7,#8957e5);font-weight:700;margin-bottom:12px}
.steps4 h3{margin:0 0 6px;font-size:17px}.steps4 p{margin:0;color:#c9d1d9;font-size:15px}
.uc{display:grid;grid-template-columns:repeat(auto-fit,minmax(250px,1fr));gap:16px}.uc .cardx .tag{font-size:12px;color:#a5d6ff}
.demo{display:grid;grid-template-columns:repeat(auto-fit,minmax(300px,1fr));gap:14px}.demo .cardx{padding:18px}.demo .k{font-size:12px;color:var(--mut);text-transform:uppercase;letter-spacing:.4px}.demo .v{margin-top:6px}
.comp{display:grid;grid-template-columns:1.2fr 1fr;gap:18px}@media(max-width:800px){.comp{grid-template-columns:1fr}.hero h1{font-size:32px}.hero p.sub{font-size:17px}.sec2 h2{font-size:26px}.hero{padding:44px 0 40px}}
.badge2{display:flex;gap:14px;align-items:center;background:var(--card);border:1px solid var(--line);border-radius:14px;padding:18px;margin-bottom:12px}.badge2 b{font-size:16px}.badge2 small{display:block;color:var(--mut)}
details{background:var(--card);border:1px solid var(--line);border-radius:12px;padding:14px 18px;margin:10px 0}summary{cursor:pointer;font-weight:600;font-size:16px}details p{color:#c9d1d9;margin:10px 0 2px}
.ctaband{background:linear-gradient(135deg,#1f6feb,#8957e5);border-radius:18px;padding:42px 30px;text-align:center;margin:0 auto}.ctaband h2{margin:0 0 8px;font-size:30px}.ctaband p{margin:0 0 20px;color:#eef}.ctaband .btn{background:#fff;color:#0d1117;font-weight:700;padding:13px 28px;border-radius:8px}
.herogrid{display:grid;grid-template-columns:1.25fr .95fr;gap:36px;align-items:center}@media(max-width:900px){.herogrid{grid-template-columns:1fr}}
.livecard{background:linear-gradient(180deg,#161b22,#0d1117);border:1px solid #30363d;border-radius:18px;padding:20px;box-shadow:0 20px 60px #0008}
.livecard .lh{display:flex;justify-content:space-between;align-items:center;margin-bottom:12px}.livecard .lh b{font-size:16px}.livecard .live{font-size:12px;color:var(--ok)}.livecard .live:before{content:"● "}
.lrow{display:flex;gap:12px;align-items:flex-start;padding:11px 0;border-top:1px solid #21262d}.lrow .dot{flex:none;width:26px;height:26px;border-radius:50%;display:flex;align-items:center;justify-content:center;font-size:14px;font-weight:700}
.lrow .dot.ok{background:#3fb95022;color:var(--ok);border:1px solid #3fb95066}.lrow .dot.bad{background:#f8514922;color:var(--bad);border:1px solid #f8514966}.lrow .t{font-size:14px}.lrow .s{font-size:12px;color:var(--mut)}.lrow a{font-size:12px}
/* v4 (2026-09-30): concrete hero list and contact line */
.hlist{list-style:none;padding:0;margin:0 0 26px;max-width:720px}.hlist li{position:relative;padding-left:28px;margin:0 0 10px;font-size:17px;line-height:1.5;color:#c9d1d9}.hlist li:before{content:"✓";position:absolute;left:0;top:0;color:var(--ok);font-weight:700}
.contactline{margin:22px 0 0;color:#c9d1d9;font-size:15px}.contactline a{white-space:nowrap}
@media(max-width:800px){.hlist li{font-size:15.5px}}
/* chain references (2026-09-30): label + tooltip + tap-to-open info button */
.cref{position:relative;display:inline-flex;flex-wrap:wrap;align-items:center;gap:2px 6px;max-width:100%;vertical-align:middle}
.cref-l{font-size:12px;color:var(--mut);white-space:nowrap}
.cref a{overflow-wrap:anywhere;word-break:break-all;min-width:0}
.cref .cref-i{all:unset;box-sizing:border-box;display:inline-flex;align-items:center;justify-content:center;width:18px;height:18px;border-radius:50%;border:1px solid var(--line);color:var(--mut);font:italic 700 11px/1 Georgia,serif;cursor:help;flex:none}
.cref .cref-i:hover,.cref .cref-i:focus-visible,.cref.open .cref-i{color:#fff;border-color:var(--acc);background:var(--acc)}
.cref-tip{display:none;position:absolute;left:0;top:calc(100% + 6px);z-index:60;width:max-content;max-width:min(320px,86vw);background:#161b22;color:#e6edf3;border:1px solid var(--acc);border-radius:8px;padding:8px 10px;font:13px/1.45 -apple-system,"Segoe UI",Roboto,"PingFang SC","Microsoft YaHei",sans-serif;white-space:normal;box-shadow:0 6px 24px #0008;font-style:normal}
@media(hover:hover){.cref:hover .cref-tip{display:block}}
.cref.open .cref-tip{display:block}
/* v3: plain-language proofs, names instead of hex, technical details */
.cref a.proof{font-size:13px;font-weight:600;text-decoration:none;white-space:nowrap}.cref a.proof:hover{text-decoration:underline}
.cref a.named{font-weight:600;text-decoration:none}.cref a.named:after{content:" ↗";font-weight:400;color:var(--mut)}.cref a.named:hover{text-decoration:underline}
details.tech{margin-top:12px;border:1px solid var(--line);border-radius:8px;padding:6px 12px;background:#0d1117}details.tech summary{cursor:pointer;color:var(--mut);font-size:13px}
details.tech dl{margin:8px 0 4px;display:grid;grid-template-columns:minmax(120px,max-content) 1fr;gap:4px 12px;font-size:12px}details.tech dt{color:var(--mut)}details.tech dd{margin:0;overflow-wrap:anywhere;word-break:break-all;color:#c9d1d9}
@media(max-width:600px){details.tech dl{grid-template-columns:1fr}details.tech dd{margin-bottom:6px}}
.steplist{list-style:none;padding:0;margin:0;display:grid;gap:12px}.steplist li{display:flex;gap:12px;align-items:flex-start;background:var(--card);border:1px solid var(--line);border-radius:12px;padding:14px 16px}
.steplist .si{flex:none;font-size:18px;line-height:1.3}.steplist .st{font-weight:600;color:#e6edf3;margin:0 0 3px}.steplist .sd{margin:0 0 6px;color:#c9d1d9;font-size:14.5px;line-height:1.55}
#act{display:block;overflow-x:auto;max-width:100%}

/* plans (2026-09-30) */
.plans{display:grid;grid-template-columns:repeat(auto-fit,minmax(280px,1fr));gap:18px}.plan{display:flex;flex-direction:column}.plan h3{margin:6px 0 2px;font-size:20px}.plan .pp{font-size:17px;font-weight:700;color:#e6edf3;margin:0 0 8px}
.plan ul{padding-left:18px;color:#c9d1d9;margin:6px 0 12px}.plan .btn{margin-top:auto;align-self:flex-start;white-space:normal;text-align:center}.plan.paid{border-color:#8957e5aa;background:linear-gradient(180deg,#8957e51a,transparent 60%),var(--card)}
.plan .tag{align-self:flex-start}
@media(max-width:600px){.cref-tip{position:fixed;left:12px;right:12px;top:auto;bottom:16px;width:auto;max-width:none;z-index:1000;font-size:14px;padding:12px 14px}}