@font-face{font-family:"Noto Sans";src:url('/font.ttf') format('truetype');font-weight:100 900;font-display:swap}
:root{--ground:#f0f5f6;--surface:#fff;--raised:#f4f6f8;--border:#e8eaec;--rule:#f0f1f2;--control:#a7adb0;--text:#131416;--muted:#5d5f60;--accent:#1b6c80;--negative:#b4232b;--radius:8px;--gap:24px;--font:"Noto Sans",sans-serif}
*{box-sizing:border-box}body{margin:0;background:var(--ground);color:var(--text);font:14px/1.6 var(--font)}a{color:inherit;text-underline-offset:4px}button,input{font:inherit}button,a,input{outline-offset:4px}:focus-visible{outline:2px solid var(--accent)}button{cursor:pointer;min-height:44px;padding:10px 18px;background:var(--text);color:var(--surface);border:1px solid var(--text);border-radius:6px;font-weight:600;transition:transform .12s}button:active{transform:translateY(1px)}button:hover{background:var(--muted)}.secondary{background:var(--surface);color:var(--text);border-color:var(--control)}.secondary:hover{background:var(--raised)}.skip{position:absolute;left:12px;top:-60px;background:var(--surface);padding:8px;z-index:5}.skip:focus{top:8px}.frame{max-width:1256px;margin:auto;padding:0 8px 8px}header{display:flex;align-items:center;justify-content:space-between;min-height:72px;padding:0 24px;gap:24px}.brand{display:flex;align-items:center;gap:10px;font-size:20px;font-weight:600;text-decoration:none}.brand svg{width:23px;height:23px;fill:var(--accent)}nav{display:flex;gap:24px}nav a{display:inline-flex;align-items:center;min-height:44px;padding:9px 0;text-decoration:none}nav [aria-current]{box-shadow:inset 0 -2px var(--text)}.sheet{background:var(--surface);border:1px solid var(--border);border-radius:16px;padding:32px;min-width:0}.title{display:flex;align-items:center;justify-content:space-between;gap:24px;margin-bottom:24px}h1{font-size:24px;line-height:1.3;font-weight:600;margin:0 0 6px}h2{font-size:16px;font-weight:600;margin:0 0 16px}h3{font-size:14px;font-weight:600;margin:24px 0 12px}p{margin:0 0 10px}.title p,.local,.hint{color:var(--muted)}.local{font-size:12px;white-space:nowrap}form{max-width:640px;margin-bottom:24px}label{display:block;font-weight:600;margin-bottom:8px}.input-row{display:flex;gap:12px}input{width:100%;min-width:0;min-height:46px;border:1px solid var(--control);border-radius:6px;padding:10px 12px;font-variant-numeric:tabular-nums;font-size:16px}.hint{font-size:12px;margin-top:8px}.error{color:var(--negative);margin-top:8px}.answer{display:flex;align-items:center;justify-content:space-between;gap:24px;padding:20px 0;border-bottom:1px solid var(--border)}.answer h2{margin-bottom:2px;color:var(--muted);font-size:14px;font-weight:400}.answer output{display:block;font-size:30px;line-height:1.5;font-weight:400;font-variant-numeric:tabular-nums}.columns{display:grid;grid-template-columns:1fr 1fr;gap:var(--gap);margin-top:24px;align-items:start}.panel{border:1px solid var(--border);border-radius:var(--radius);padding:20px;min-width:0}dl{margin:0}dl>div{display:flex;justify-content:space-between;gap:16px;padding:10px 0;border-bottom:1px solid var(--rule)}dl>div:last-child{border:0}dt{color:var(--muted)}dd{margin:0;text-align:right;font-variant-numeric:tabular-nums;white-space:nowrap}.bits{display:grid;grid-template-columns:repeat(16,1fr);gap:4px;font-variant-numeric:tabular-nums;margin:12px 0}.bit{height:28px;display:grid;place-items:center;background:var(--raised);border-radius:2px;font-size:12px}.bit.net{background:var(--accent);color:var(--surface)}.bit-key{display:flex;gap:24px;color:var(--muted);font-size:12px}.bit-key span{display:flex;align-items:center;gap:5px}.bit-key i{width:9px;height:9px;display:inline-block}.network-bit{background:var(--accent)}.host-bit{background:var(--control)}.split{display:flex;justify-content:space-between;gap:12px;font-variant-numeric:tabular-nums}.reference{max-width:800px;margin-top:32px}.reference p{color:var(--muted)}footer{display:flex;justify-content:space-between;gap:24px;color:var(--muted);font-size:12px;margin-top:32px}.prose{max-width:780px;margin:32px auto}.prose p{font-size:16px;margin:16px 0}.prose h2{margin-top:28px}.prose .back{display:inline-block;margin-bottom:24px}
/* Desktop: two equal columns plus one 24px gutter; both align to the sheet edges. */
@media(max-width:800px){.columns{grid-template-columns:1fr}.sheet{padding:24px}.local{display:none}header{padding:0 20px}.panel{padding:20px}.bits{grid-template-columns:repeat(16,1fr)}}
@media(max-width:480px){body{font-size:14px}.frame{padding:0}.sheet{border-radius:0;border-left:0;border-right:0;padding:24px 18px}header{min-height:64px;padding:0 18px;gap:12px}.brand{font-size:18px}.brand svg{width:20px}nav{gap:14px;font-size:12px}.input-row{flex-wrap:wrap}.input-row input,.input-row button{width:100%}.title{margin-bottom:24px}h1{font-size:22px}.answer{align-items:start;flex-direction:column;gap:12px}.answer output{font-size:28px}.answer .secondary{width:100%}.columns{gap:24px}.panel{padding:16px}dl>div{gap:8px;font-size:13px}dt{max-width:48%}.bits{gap:3px}.bit{font-size:11px;height:25px}.split{flex-direction:column;gap:0}footer{margin-top:24px}.prose{padding:0 18px}}
@media(prefers-reduced-motion:reduce){*{transition:none!important;scroll-behavior:auto!important}}