:root{--canvas:#0a0a0a;--soft:#1a1c20;--card:#191919;--mid:#363a3f;--hair:#212327;--ink:#fff;--body:#dadbdf;--mute:#7d8187;
--pill:rgba(255,255,255,.25);--ok:#6ee7b7;--warn:#ff7a17;--sunset:#ffc285;--twilight:#c4b5fd;--breeze:#a0c3ec}
*{box-sizing:border-box;margin:0;padding:0}
html{background:var(--canvas);color:var(--ink);-webkit-font-smoothing:antialiased;text-rendering:optimizeLegibility;overflow-x:clip}
body{font:400 16px/1.6 Inter,system-ui,sans-serif;background:var(--canvas);min-height:100vh;overflow-x:clip}
a{color:inherit;text-decoration:none}
.wrap{max-width:1200px;margin:0 auto;padding:0 24px}
.mono{font-family:'Geist Mono',ui-monospace,monospace;text-transform:uppercase;letter-spacing:1.4px;font-size:12px;color:var(--mute)}
nav{display:flex;align-items:center;justify-content:space-between;height:72px;border-bottom:1px solid var(--hair)}
nav .brand{display:flex;align-items:center;gap:12px;font-size:15px;letter-spacing:-.01em}
nav .dot{width:9px;height:9px;border-radius:50%;background:var(--ink);box-shadow:0 0 0 4px rgba(255,255,255,.08)}
.pill{display:inline-flex;align-items:center;gap:8px;height:36px;padding:0 16px;border:1px solid var(--pill);border-radius:9999px;font-size:14px;color:var(--ink);transition:background .15s,border-color .15s;white-space:nowrap}
.pill:hover{background:var(--soft);border-color:rgba(255,255,255,.45)}
.pill.solid{background:var(--ink);color:#0a0a0a;border-color:var(--ink)}
.pill.solid:hover{background:#e9e9e6}
.tag{display:inline-flex;align-items:center;gap:7px;height:24px;padding:0 10px;border-radius:9999px;border:1px solid var(--hair);font:400 11px/1 'Geist Mono',monospace;letter-spacing:1.1px;text-transform:uppercase;color:var(--body)}
.tag i{width:6px;height:6px;border-radius:50%;background:var(--mute)}
.tag.ok i{background:var(--ok);box-shadow:0 0 10px var(--ok)}.tag.warn i{background:var(--warn)}
.hero{position:relative;padding:120px 0 72px;isolation:isolate}
.hero::before{content:"";position:absolute;inset:-1px -50vw;z-index:-1;
background:radial-gradient(60% 70% at 70% 0%,rgba(124,58,237,.18),transparent 70%),radial-gradient(40% 50% at 15% 20%,rgba(255,122,23,.10),transparent 70%);
mask:linear-gradient(#000 40%,transparent)}
.hero::after{content:"";position:absolute;inset:0 -50vw;z-index:-1;opacity:.35;
background-image:linear-gradient(var(--hair) 1px,transparent 1px),linear-gradient(90deg,var(--hair) 1px,transparent 1px);background-size:64px 64px;
mask:radial-gradient(70% 80% at 50% 0%,#000,transparent 75%)}
h1{font-weight:400;font-size:clamp(48px,9vw,104px);line-height:1.04;letter-spacing:-.045em;margin:20px 0 24px;max-width:14ch}
h1 em{font-style:normal;color:var(--mute)}
.lead{font-size:clamp(17px,2vw,20px);line-height:1.55;color:var(--body);max-width:60ch}
.stats{display:grid;grid-template-columns:repeat(4,1fr);border:1px solid var(--hair);border-radius:8px;margin:56px 0 0;overflow:hidden}
.stats div{padding:22px 24px;border-left:1px solid var(--hair)}.stats div:first-child{border-left:0}
.stats b{display:block;font-weight:400;font-size:40px;line-height:1.1;letter-spacing:-.03em;margin-top:8px}
section.blk{padding:72px 0;border-top:1px solid var(--hair)}
h2{font-weight:400;font-size:clamp(30px,4vw,48px);line-height:1.12;letter-spacing:-.03em;margin:12px 0 40px}
/* Cây: mỗi cấp là một cột, đường nối mảnh */
.tree,.tree ul{list-style:none}
.tree li{position:relative;display:flex;align-items:center}
.tree ul{position:relative;padding-left:56px;display:flex;flex-direction:column}
.tree ul>li{padding:7px 0}
.tree ul>li::before{content:"";position:absolute;left:-28px;top:50%;width:28px;border-top:1px solid var(--mid)}
.tree ul>li::after{content:"";position:absolute;left:-28px;top:0;bottom:0;border-left:1px solid var(--mid)}
.tree ul>li:first-child::after{top:50%}.tree ul>li:last-child::after{bottom:50%}
.tree ul>li:only-child::after{display:none}
.tree li>.node+ul::before{content:"";position:absolute;left:0;top:50%;width:28px;border-top:1px solid var(--mid)}
.node{flex:none;border:1px solid var(--hair);border-radius:8px;background:var(--card)}
.node.root{padding:18px 22px;border-color:var(--pill);border-radius:9999px;background:transparent;display:flex;align-items:center;gap:12px;font-size:17px;letter-spacing:-.01em}
.node.root .dot{width:9px;height:9px;border-radius:50%;background:#fff;box-shadow:0 0 18px rgba(255,255,255,.6)}
.node.kind{padding:10px 16px;border-radius:9999px;background:transparent}
.card{display:block;width:min(600px,calc(100vw - 420px));padding:20px 22px;transition:border-color .15s,background .15s,transform .2s}
.card:hover{border-color:rgba(255,255,255,.35);background:#1d1d1d;transform:translateX(3px)}
.card .top{display:flex;justify-content:space-between;align-items:center;gap:12px}
.card h3{font-weight:400;font-size:22px;letter-spacing:-.02em;line-height:1.2}
.card p{color:var(--body);font-size:14px;line-height:1.5;margin:6px 0 14px}
.card .meta{display:flex;flex-wrap:wrap;gap:6px 18px}
.card .meta span b{color:var(--ink);font-weight:400;margin-left:6px}
.card .go{color:var(--mute);font-size:13px;margin-top:14px;display:flex;justify-content:space-between}
.card:hover .go span:last-child{color:var(--ink)}
/* Trang chi tiết */
.back{display:inline-flex;margin:32px 0 0}
.d-hero{padding:72px 0 40px}
.d-hero h1{max-width:18ch}
.actions{display:flex;flex-wrap:wrap;gap:10px;margin-top:32px}
.three{display:grid;grid-template-columns:200px 1fr;gap:40px;padding:56px 0;border-top:1px solid var(--hair)}
.three .k{position:sticky;top:24px;align-self:start}
.three>*{min-width:0}
.three .k b{display:block;font-weight:400;font-size:28px;letter-spacing:-.02em;color:var(--ink);margin-top:10px;text-transform:none;font-family:Inter,sans-serif;line-height:1.2}
.prose{color:var(--body);max-width:72ch}
.prose p,.prose ul,.prose ol,.prose .tbl{margin:0 0 16px}
.prose ul,.prose ol{padding-left:20px}.prose li{margin:4px 0}.prose li::marker{color:var(--mute)}
.prose h4{font-weight:400;font-size:20px;letter-spacing:-.01em;color:var(--ink);margin:28px 0 10px}
.prose strong{color:var(--ink);font-weight:400}
.prose code{font-family:'Geist Mono',monospace;font-size:.86em;background:var(--soft);border:1px solid var(--hair);border-radius:4px;padding:1px 6px;color:var(--ink);word-break:break-word}
.prose a{border-bottom:1px solid var(--pill)}
.tbl{overflow-x:auto;border:1px solid var(--hair);border-radius:8px}
table{border-collapse:collapse;width:100%;font-size:14px}
th{font:400 11px/1.4 'Geist Mono',monospace;letter-spacing:1.1px;text-transform:uppercase;color:var(--mute);text-align:left}
th,td{padding:10px 14px;border-bottom:1px solid var(--hair);vertical-align:top}tr:last-child td{border-bottom:0}
.flow{display:grid;grid-template-columns:repeat(6,1fr);gap:0;margin:8px 0 32px;border:1px solid var(--hair);border-radius:8px;overflow:hidden}
.flow div{padding:16px;border-left:1px solid var(--hair);min-height:110px}.flow div:first-child{border-left:0}
.flow div.on{background:linear-gradient(180deg,rgba(255,255,255,.04),transparent)}
.flow b{display:block;font-weight:400;color:var(--ink);font-size:15px;margin:8px 0 4px;letter-spacing:-.01em}
.flow small{color:var(--mute);font-size:13px;line-height:1.4;display:block}
.empty{color:var(--mute)}
footer{border-top:1px solid var(--hair);padding:32px 0 48px;margin-top:40px;display:flex;justify-content:space-between;gap:16px;flex-wrap:wrap}
@media (max-width:860px){
 .stats{grid-template-columns:repeat(2,1fr)}.stats div:nth-child(3){border-left:0}.stats div:nth-child(n+3){border-top:1px solid var(--hair)}
 .tree li{display:block}.tree ul{padding-left:20px;margin-top:8px}
 .tree ul>li::before{left:-12px;width:12px;top:36px}.tree ul>li::after{left:-12px}
 .tree ul>li:first-child::after{top:0}.tree ul>li:last-child::after{bottom:auto;height:36px}
 .tree ul>li:only-child::after{display:block;top:0;bottom:auto;height:36px}
 .tree li>.node+ul::before{display:none}
 .node.root,.node.kind{display:inline-flex}.card{width:100%;padding:18px}.card .meta{gap:4px 14px}
 .prose code{white-space:normal}.tbl table{min-width:520px}
 .three{grid-template-columns:1fr;gap:16px}.three .k{position:static}
 .flow{grid-template-columns:repeat(2,1fr)}.flow div:nth-child(odd){border-left:0}.flow div:nth-child(n+3){border-top:1px solid var(--hair)}
 .hero{padding:72px 0 48px}
}
@media (prefers-reduced-motion:reduce){*{transition:none!important}}