:root{--ink:#171717;--muted:#4a4a4a;--line:#767676;--line-strong:#333;--soft:#f2f2f2;--paper:#fff;--game:#090909;--ud-red:#ff4b00;--ud-orange:#f6aa00;--ud-green:#03af7a;--ud-blue:#005aff;--ud-sky:#4dc4ff;--interactive:var(--ud-blue);--error-text:#8a2600;--mono:ui-monospace, "SFMono-Regular", Consolas, monospace;--sans:Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif}*{box-sizing:border-box}html{scroll-behavior:smooth}body{min-width:320px;color:var(--ink);background:var(--paper);font-family:var(--sans);-webkit-font-smoothing:antialiased;margin:0;font-size:18px;line-height:1.6}button,textarea{font:inherit}button{color:inherit}a{color:var(--interactive);text-underline-offset:3px;font-weight:650;text-decoration-thickness:1.5px}a:hover{text-decoration-thickness:3px}a:focus-visible,button:focus-visible,textarea:focus-visible{outline:3px solid var(--interactive);outline-offset:3px}.skip-link{z-index:100;color:#fff;background:var(--interactive);border:2px solid #fff;padding:10px 14px;position:fixed;top:8px;left:8px;transform:translateY(-150%)}.skip-link:focus{transform:translateY(0)}.connection-bar{border-bottom:2px solid var(--line-strong);justify-content:space-between;align-items:center;min-height:64px;padding:10px 0;display:flex}.brand{color:var(--interactive);letter-spacing:0;font-size:16px;font-weight:800}.connection-actions,.connection-pill{align-items:center;display:flex}.connection-actions{flex-wrap:wrap;justify-content:flex-end;gap:8px 14px;display:flex}.connection-pill{min-height:34px;color:var(--ink);background:var(--soft);border:1px solid var(--line);border-radius:3px;gap:7px;padding:3px 9px;font-size:16px;font-weight:650}.header-link{color:var(--interactive);font-size:16px}.status-symbol{color:#fff;width:20px;height:20px;font:800 15px/1 var(--sans);background:#5f5f5f;border-radius:2px;place-items:center;display:grid}.connection-pill[data-state=connecting]{border-style:dashed}.connection-pill[data-state=connecting] .status-symbol{color:var(--ink);background:var(--ud-orange);animation:1s infinite pulse}.connection-pill[data-state=connected]{border-color:#007a55}.connection-pill[data-state=connected] .status-symbol{color:var(--ink);background:var(--ud-green)}.connection-pill[data-state=error]{border:2px solid var(--ud-red)}.connection-pill[data-state=error] .status-symbol{background:var(--error-text)}.text-button{min-height:34px;color:var(--interactive);background:var(--paper);border:1px solid var(--interactive);cursor:pointer;text-underline-offset:3px;border-radius:3px;padding:3px 10px;font-size:16px;font-weight:650;text-decoration:underline}.text-button:hover{color:#fff;background:var(--interactive)}main{width:min(100% - 32px,960px);margin:0 auto}.setup-shell{padding:clamp(56px,10vw,100px) 0 72px}.intro{text-align:center;margin-bottom:38px}.intro h1{letter-spacing:-.025em;margin:0;font-size:clamp(30px,6vw,46px);line-height:1.25}.intro p{color:var(--muted)}.intro-description{max-width:560px;margin:16px auto 0;font-size:clamp(18px,2.1vw,20px);line-height:1.75}.intro-instruction{margin:20px 0 0;font-size:17px;font-weight:700}.role-grid{grid-template-columns:1fr 1fr;gap:12px;width:min(100%,620px);margin:0 auto;display:grid}.role-card{background:var(--paper);border:2px solid var(--line-strong);min-height:150px;box-shadow:0 3px 0 var(--line-strong);cursor:pointer;text-align:left;border-radius:4px;flex-direction:column;justify-content:center;gap:8px;padding:24px;display:flex}.role-card:hover{border-color:var(--interactive);box-shadow:0 3px 0 var(--interactive);background:#edf5ff}.role-card strong{font-size:20px}.role-card span{color:var(--muted);font-size:16px}.role-card .role-action{color:var(--interactive);text-underline-offset:3px;margin-top:8px;font-weight:750;text-decoration:underline}.wizard-panel{width:min(100%,760px);margin:0 auto}.steps{grid-template-columns:repeat(3,1fr);gap:8px;margin:0 0 36px;padding:0;list-style:none;display:grid}.steps li{min-height:74px;color:var(--muted);background:var(--paper);border:1px solid var(--line);text-align:center;flex-direction:column;justify-content:center;align-items:center;gap:4px;padding:10px 8px;font-size:16px;display:flex}.steps li.active{color:var(--ink);border:2px solid var(--interactive);background:#edf5ff}.steps li.done{color:var(--ink);background:var(--soft);border-color:var(--line-strong)}.step-marker{color:#fff;background:var(--muted);border-radius:50%;place-items:center;width:24px;height:24px;font-size:15px;font-weight:800;display:grid}.steps li.active .step-marker{background:var(--interactive)}.steps li.done .step-marker{color:var(--ink);background:var(--ud-green);border-radius:2px}.code-layout{grid-template-columns:260px 1fr;align-items:center;gap:30px;display:grid}.qr-column{text-align:center}.qr-column p{color:var(--muted);margin:9px 0 0;font-size:16px;line-height:1.6}.qr-frame{border:2px solid var(--line-strong);background:#fff;place-items:center;width:240px;height:240px;margin:0 auto;display:grid;position:relative}.qr-frame canvas{object-fit:contain;width:100%;height:100%}.qr-loading{color:var(--muted);font-size:16px;font-weight:700;position:absolute}label{margin-bottom:8px;font-size:16px;font-weight:750;display:block}textarea{resize:vertical;width:100%;color:var(--ink);background:var(--paper);border:2px solid var(--line-strong);font:16px/1.6 var(--mono);border-radius:3px;padding:12px}textarea::placeholder{color:#595959;opacity:1}textarea:read-only{background:var(--soft);border-style:dashed}textarea:focus{border-color:var(--interactive)}.button-row{justify-content:flex-end;gap:8px;margin-top:10px;display:flex}.button{border:2px solid var(--interactive);cursor:pointer;border-radius:3px;min-height:48px;padding:0 18px;font-size:16px;font-weight:750}.button.primary{color:#fff;background:var(--interactive)}.button.secondary{color:var(--interactive);background:var(--paper)}.button.primary:hover{background:#003fba}.button.secondary:hover{color:#fff;background:var(--interactive)}.button.full{width:100%;margin-top:8px}.button:disabled,.serve-button:disabled{color:#595959;opacity:1;cursor:not-allowed;background:#e5e5e5;border-color:#8a8a8a}.next-step{border-top:1px solid var(--line);margin-top:34px;padding-top:30px}.next-step.first{border-top:0;margin-top:0;padding-top:0}.inline-status{min-height:48px;color:var(--ink);background:var(--soft);border:1px solid var(--line);justify-content:space-between;align-items:center;gap:12px;margin:22px 0 0;padding:10px 12px;font-size:16px;line-height:1.7;display:flex}.inline-status.error{color:var(--error-text);border:2px solid var(--ud-red);background:#fff4ef}.inline-retry{color:#fff;background:var(--error-text);border:2px solid var(--error-text);cursor:pointer;border-radius:3px;flex:none;min-height:40px;padding:5px 12px;font-size:15px;font-weight:750}.inline-retry:hover{color:var(--error-text);background:#fff}.game-shell{color:#f5f5f5;padding:40px 0 64px}.game-topline{justify-content:space-between;align-items:center;margin-bottom:16px;display:flex}.game-topline h1{color:var(--ink);letter-spacing:-.03em;margin:0;font-size:20px}.latency{color:var(--ink);font:16px var(--mono);gap:7px;display:flex}.latency span{color:var(--muted)}.scoreboard{color:#fff;background:var(--game);grid-template-columns:1fr auto 1fr;align-items:center;padding:14px 22px;display:grid}.scoreboard>div:last-child{text-align:right}.scoreboard small{color:#d0d0d0;font:15px var(--mono);display:block}.scoreboard strong{font:500 clamp(34px, 7vw, 58px)/1 var(--mono)}.match-state{color:#e0e0e0;max-width:250px;font:15px/1.5 var(--mono);text-align:center}.canvas-frame{background:var(--game);position:relative}#gameCanvas{aspect-ratio:16/9;width:100%;display:block}.canvas-overlay{text-align:center;background:#090909d6;flex-direction:column;justify-content:center;align-items:center;gap:7px;display:flex;position:absolute;inset:0}.canvas-overlay small{color:#ddd}.game-controls{color:#fff;background:var(--game);font:16px var(--mono);border-top:2px solid #767676;grid-template-columns:1fr auto 1fr;align-items:center;gap:12px;padding:14px 18px;display:grid;position:relative}.afk-toggle{color:#fff;cursor:pointer;min-width:84px;min-height:44px;font:700 14px/1.1 var(--mono);background:#222;border:1px solid #aaa;border-radius:3px;padding:4px 10px;position:absolute;bottom:12px;right:12px}.afk-toggle small{color:#bbb;font:11px var(--sans);margin-top:3px;display:block}.afk-toggle.active{color:var(--ink);background:var(--ud-green);border-color:#fff}.afk-toggle.active small{color:var(--ink)}.serve-button{color:#fff;background:var(--interactive);cursor:pointer;border:2px solid #fff;border-radius:3px;min-height:48px;padding:0 20px;font-weight:750}.serve-button:hover:not(:disabled){background:#003fba}.touch-controls{justify-content:flex-end;gap:7px;display:none}.touch-controls button{width:52px;height:48px;color:var(--ink);touch-action:none;background:#fff;border:2px solid #fff;border-radius:3px;font-size:20px}.touch-controls button:active{color:#fff;background:var(--interactive)}.scanner-dialog{color:#fff;background:var(--game);border:3px solid #fff;border-radius:3px;width:min(92vw,560px);padding:20px}.scanner-dialog::backdrop{background:#000000b8}.scanner-header{justify-content:space-between;align-items:center;margin-bottom:16px;display:flex}.scanner-header h2{margin:0;font-size:18px}.scanner-header button{color:#fff;cursor:pointer;background:0 0;border:2px solid #fff;border-radius:3px;width:44px;height:44px;font-size:24px}.camera-frame{aspect-ratio:4/3;background:#000;position:relative;overflow:hidden}.camera-frame video{object-fit:cover;width:100%;height:100%}.scan-guide{border:2px solid #fff;position:absolute;inset:14%;box-shadow:0 0 0 999px #00000038}.scanner-dialog p{color:#fff;text-align:center;margin:14px 0 0;font-size:16px}.technical-explanation{border-top:2px solid var(--line-strong);margin:24px 0 0;padding:clamp(72px,11vw,112px) 0 96px}.article-lead{margin-bottom:48px}.article-lead h2{letter-spacing:-.025em;margin:0;font-size:clamp(27px,5vw,42px);line-height:1.25}.article-lead>p{color:var(--ink);margin:24px 0 0;font-size:18px;line-height:1.9}.glossary-jump{color:var(--interactive);text-underline-offset:4px;margin-top:20px;font-size:17px;display:inline-block}.handshake-figure{margin:0 0 72px}.handshake-diagram{width:100%;height:auto;color:var(--ink);background:var(--soft);border:2px solid var(--line-strong);display:block}.handshake-diagram-mobile{display:none}.handshake-figure figcaption{color:var(--muted);margin-top:12px;font-size:16px;line-height:1.7}.diagram-peer{fill:#fff;stroke:#767676;stroke-width:2px}.diagram-kicker{fill:#4a4a4a;font:700 14px var(--mono);letter-spacing:.1em}.diagram-title{fill:#111;font:650 17px var(--sans)}.diagram-life{stroke:#767676;stroke-dasharray:4 7}.diagram-arrow{stroke:currentColor;stroke-width:2px}.diagram-step{fill:#111;font:650 15px var(--sans)}.diagram-detail{fill:#4a4a4a;font:15px var(--sans)}.diagram-channel{fill:#111}.diagram-channel-line{stroke:#fff;stroke-width:1.4px;opacity:.65}.diagram-channel-label{fill:#fff;font:650 15px var(--sans)}.diagram-channel-detail{fill:#ddd;font:14px var(--mono)}.article-section{grid-template-columns:84px minmax(0,620px);gap:28px;margin-top:56px;display:grid}.section-number{color:var(--muted);font:16px var(--mono);border-top:2px solid var(--line-strong);padding-top:5px}.article-section h3,.network-note h3{letter-spacing:-.02em;margin:0 0 16px;font-size:19px}.article-section p,.network-note p{color:var(--ink);margin:0;font-size:18px;line-height:1.9}.article-section p+p{margin-top:18px}.article-section code{background:var(--soft);border:1px solid var(--line);font:16px var(--mono);border-radius:3px;padding:2px 5px}.network-note{background:var(--soft);border:2px solid var(--line-strong);max-width:732px;margin:64px 0 0 112px;padding:26px 28px}.network-note h3{font-size:18px}.network-note p{font-size:17px;line-height:1.8}.glossary{border-top:2px solid var(--line-strong);margin-top:88px;padding-top:72px;scroll-margin-top:24px}.glossary-header{max-width:620px}.glossary-header h2{letter-spacing:-.035em;margin:0;font-size:clamp(26px,4vw,36px)}.glossary-header>p:last-child{color:var(--muted);margin:16px 0 0;font-size:17px;line-height:1.8}.glossary-list{border-top:2px solid var(--line-strong);margin:40px 0 0}.glossary-item{border-bottom:1px solid var(--line);grid-template-columns:190px minmax(0,1fr);gap:32px;padding:24px 0;display:grid}.glossary-item dt{font:750 17px/1.6 var(--mono)}.glossary-item dd{color:var(--ink);margin:0;font-size:17px;line-height:1.8}.glossary-item a{width:fit-content;color:var(--interactive);text-underline-offset:3px;margin-top:8px;font-weight:650;display:block}.toast{z-index:40;color:#fff;opacity:0;pointer-events:none;background:#111;border-radius:5px;padding:10px 14px;font-size:16px;transition:all .2s;position:fixed;bottom:22px;left:50%;transform:translate(-50%,10px)}.toast.show{opacity:1;transform:translate(-50%)}.hidden{display:none!important}@keyframes pulse{50%{opacity:.3}}@media (width<=620px){.connection-bar{padding:10px 0}main{width:min(100% - 24px,880px)}.setup-shell{padding-top:44px}.intro{margin-bottom:28px}.intro-description{max-width:330px;line-height:1.7}.intro-instruction{max-width:260px;margin-inline:auto;line-height:1.5}.role-grid{grid-template-columns:1fr}.role-card{min-height:96px;padding:20px}.steps li{min-height:88px;padding-inline:4px;font-size:15px}.code-layout{grid-template-columns:1fr;gap:24px}.qr-column{order:-1}.game-shell{padding-top:24px}.scoreboard{padding-inline:14px}.match-state{max-width:150px;font-size:14px}.control-guide{display:none}.game-controls{grid-template-columns:1fr 1fr}.touch-controls{display:flex}.technical-explanation{padding:64px 0 72px}.article-lead{margin-bottom:34px}.article-lead>p{font-size:17px;line-height:1.9}.handshake-figure{margin-inline:-4px;margin-bottom:56px}.handshake-diagram:not(.handshake-diagram-mobile){display:none}.handshake-diagram-mobile{display:block}.article-section{grid-template-columns:34px minmax(0,1fr);gap:16px;margin-top:46px}.article-section p{font-size:17px;line-height:1.9}.network-note{margin:52px 0 0;padding:22px}.glossary{margin-top:64px;padding-top:56px}.glossary-list{margin-top:30px}.glossary-item{grid-template-columns:1fr;gap:8px;padding:21px 0}}@media (width<=480px){.connection-bar{flex-direction:column;align-items:flex-start;gap:10px}.connection-actions{justify-content:flex-start;width:100%}.status-prefix{clip-path:inset(50%);white-space:nowrap;width:1px;height:1px;position:absolute;overflow:hidden}.button-row{flex-direction:column}.button-row .button{width:100%}.inline-status{flex-direction:column;align-items:stretch}.inline-retry{width:100%}.steps{gap:4px}.steps li{font-size:15px}}@media (prefers-reduced-motion:reduce){*,:before,:after{scroll-behavior:auto!important;transition:none!important;animation:none!important}}