:root{--bg:#08090c;--panel:#0d0f14;--line:rgba(255,255,255,0.09);--text:#f2f5fa;--muted:rgba(242,245,250,0.5);--gold:#ffc61a;--good:#57deb6;--bad:#ff9b82;--warn:#ffd76b;--radius:14px;color-scheme:dark}*{box-sizing:border-box}body,html{margin:0;height:100%;background:var(--bg);color:var(--text);font:400 15px/1.6 DM Sans,system-ui,-apple-system,sans-serif;-webkit-font-smoothing:antialiased}h1,h2,h3{font-family:Space Grotesk,system-ui,sans-serif;letter-spacing:-.02em}h1{font-size:28px;margin:6px 0 4px}h2{font-size:18px;margin:0 0 2px}h3{font-size:15px;margin:22px 0 6px}a{color:var(--gold);text-decoration:none}a:hover{color:#ffde6b}.muted{color:var(--muted)}.small{font-size:13px}.spacer{flex:1 1}.centre{min-height:100dvh;display:grid;place-items:center;padding:32px 20px;grid-gap:16px;gap:16px;align-content:center}.wrap{max-width:860px;margin:0 auto;padding:28px 20px 72px}.page-head{margin-bottom:28px}.btn{display:inline-flex;align-items:center;justify-content:center;min-height:40px;padding:0 18px;border:0;border-radius:11px;background:linear-gradient(180deg,#ffde6b,var(--gold) 55%,#dda800);color:#1a1200;font:700 14px Space Grotesk,system-ui,sans-serif;cursor:pointer}.btn:hover{filter:brightness(1.06);color:#1a1200}.btn:disabled{opacity:.45;cursor:not-allowed;filter:none}.btn-quiet{background:rgba(255,255,255,.05);border:1px solid var(--line);color:var(--text)}.btn-quiet:hover{border-color:rgba(255,198,26,.45);color:var(--text)}select{min-height:36px;padding:0 10px;border-radius:10px;border:1px solid var(--line);background:rgba(255,255,255,.03);color:var(--text);font:500 13px DM Sans,sans-serif}.card{width:min(420px,100%);padding:28px;border-radius:22px;border:1px solid var(--line);background:var(--panel);text-align:center}.pair h2{font-size:22px}.qr{width:240px;height:240px;margin:22px auto 14px;padding:10px;border-radius:16px;background:#fff;display:grid;place-items:center}.qr svg{display:block}.qr svg,.qr-skeleton{width:100%;height:100%}.qr-skeleton{background:#e9e9e9;border-radius:8px}.code{margin:4px 0;font:700 26px JetBrains Mono,ui-monospace,monospace;letter-spacing:.12em;color:var(--gold)}.steps{margin:22px 0 0;padding-left:20px;text-align:left;color:var(--muted);font-size:13.5px}.steps li{margin:6px 0}.notice{padding:12px 16px;border-radius:12px;border:1px solid var(--line);background:rgba(255,255,255,.03);font-size:14px}.notice.error{border-color:rgba(255,155,130,.4);color:var(--bad)}.session-bar{position:-webkit-sticky;position:sticky;top:0;z-index:10;gap:16px;padding:10px 20px;border-bottom:1px solid var(--line);background:rgba(8,9,12,.85);-webkit-backdrop-filter:blur(12px);backdrop-filter:blur(12px)}.brand,.session-bar{display:flex;align-items:center}.brand{gap:8px;color:var(--text);font:700 12px JetBrains Mono,monospace;letter-spacing:.24em}.brand-mark{color:var(--gold)}.session-who{margin-left:auto;font-size:13px;color:var(--muted)}.session-who strong{color:var(--text)}.section{margin-bottom:34px}.problems{list-style:none;margin:14px 0 0;padding:0}.problems li{margin-bottom:8px}.problem{display:flex;align-items:center;gap:14px;padding:14px 16px;border:1px solid var(--line);border-radius:var(--radius);background:rgba(255,255,255,.02);color:var(--text)}a.problem:hover{border-color:rgba(255,198,26,.4);color:var(--text)}.problem.locked{opacity:.5}.problem-mark{width:18px;text-align:center;color:var(--gold)}.problem-body{display:flex;flex-direction:column;min-width:0;flex:1 1}.problem-title{font:600 15px Space Grotesk,sans-serif}.chip{padding:4px 9px;border-radius:20px;border:1px solid var(--line);font:500 10px JetBrains Mono,monospace;text-transform:uppercase;letter-spacing:.08em;color:var(--muted)}.chip-hard{color:var(--bad);border-color:rgba(255,155,130,.35)}.chip-medium{color:var(--warn);border-color:rgba(255,215,107,.3)}.split{display:grid;grid-template-columns:minmax(320px,.9fr) minmax(420px,1.1fr);height:calc(100dvh - 53px)}.pane{min-width:0;overflow-y:auto}.statement{padding:0;border-right:1px solid var(--line)}.statement-tabs{position:-webkit-sticky;position:sticky;top:0;z-index:4;display:flex;gap:4px;padding:10px 16px 0;border-bottom:1px solid var(--line);background:rgba(8,9,12,.94);-webkit-backdrop-filter:blur(12px);backdrop-filter:blur(12px)}.statement-tab{position:relative;min-height:38px;padding:0 13px 9px;border:0;background:transparent;color:var(--muted);font:650 13px Space Grotesk,system-ui,sans-serif;cursor:pointer}.statement-tab:hover{color:var(--text)}.statement-tab:after{content:"";position:absolute;left:12px;right:12px;bottom:-1px;height:2px;border-radius:2px 2px 0 0;background:transparent}.statement-tab.active{color:var(--text)}.statement-tab.active:after{background:var(--gold)}.statement-tab-content{padding:18px 26px 60px}.back{font-size:13px}.prose p,.sample{margin:10px 0}.sample{display:grid;grid-template-columns:1fr 1fr;grid-gap:12px;gap:12px;padding:12px;border:1px solid var(--line);border-radius:12px}pre{margin:4px 0 0;padding:10px;border-radius:8px;background:rgba(255,255,255,.03);font:500 12.5px/1.5 JetBrains Mono,ui-monospace,monospace;white-space:pre-wrap;overflow-wrap:anywhere}.editor{display:flex;flex-direction:column;overflow:hidden}.toolbar{display:flex;align-items:center;gap:10px;padding:10px 14px;border-bottom:1px solid var(--line)}.monaco{flex:1 1;min-height:240px}.results{border-top:1px solid var(--line);padding:14px 16px 18px;max-height:42%;overflow-y:auto}.kbd-hint{margin-top:12px}.verdict{display:flex;flex-direction:column;gap:6px}.verdict-line{margin:0;font:700 15px Space Grotesk,sans-serif}.verdict.good .verdict-line{color:var(--good)}.verdict.bad .verdict-line{color:var(--bad)}.verdict.warn .verdict-line{color:var(--warn)}.verdict.pending{flex-direction:row;flex-wrap:wrap;align-items:center;gap:10px;color:var(--muted)}.hint{margin:2px 0;font-size:13px;color:var(--warn)}.reward{margin:0;color:var(--gold);font:650 12.5px Space Grotesk,system-ui,sans-serif}.output{max-height:180px;overflow:auto}.output.error{color:var(--bad)}.diff-grid{display:grid;grid-template-columns:repeat(3,1fr);grid-gap:10px;gap:10px}.solved-actions{margin-top:12px}.spinner{width:14px;height:14px;border:2px solid rgba(255,255,255,.18);border-top:2px solid var(--gold);border-radius:50%;animation:spin .8s linear infinite}@keyframes spin{to{transform:rotate(1turn)}}@media (max-width:900px){.split{grid-template-columns:1fr;height:auto}.statement{border-right:0;border-bottom:1px solid var(--line)}.statement-tabs{position:-webkit-sticky;position:sticky;top:0}.statement-tab-content{padding:18px 18px 44px}.monaco{height:50vh}.results{max-height:none}.diff-grid,.sample{grid-template-columns:1fr}}@media (prefers-reduced-motion:reduce){.spinner{animation:none}}.current-result{padding-bottom:14px}.result-section-label{display:flex;align-items:baseline;justify-content:space-between;gap:12px;margin-bottom:8px;color:var(--muted);font:700 10px JetBrains Mono,ui-monospace,monospace;letter-spacing:.12em;text-transform:uppercase}.submission-history{margin:0;padding:0}.submission-history-head{display:flex;align-items:flex-start;justify-content:space-between;gap:16px;margin-bottom:14px}.submission-history-head h3{margin:0;font-size:15px}.submission-history-head p{margin:2px 0 0}.history-refresh{flex:0 0 auto;border:0;background:transparent;color:var(--muted);padding:3px 0;font:600 12px DM Sans,sans-serif;cursor:pointer}.history-refresh:hover{color:var(--text)}.history-refresh:disabled{opacity:.5;cursor:default}.submission-history-empty{display:flex;flex-direction:column;gap:2px;padding:16px;border:1px dashed var(--line);border-radius:12px;background:rgba(255,255,255,.015)}.submission-list{display:flex;flex-direction:column;gap:7px}.submission-entry{overflow:hidden;border:1px solid var(--line);border-radius:12px;background:rgba(255,255,255,.018);transition:border-color .12s ease,background .12s ease}.submission-entry.open,.submission-entry:hover{border-color:rgba(255,198,26,.24);background:rgba(255,255,255,.025)}.submission-summary{width:100%;min-height:58px;display:grid;grid-template-columns:10px minmax(0,1fr) auto 18px;align-items:center;grid-gap:11px;gap:11px;padding:10px 12px;border:0;background:transparent;color:var(--text);text-align:left;cursor:pointer}.submission-summary:hover{background:rgba(255,255,255,.02)}.submission-dot{width:8px;height:8px;border-radius:50%;background:var(--muted);box-shadow:0 0 0 3px rgba(255,255,255,.025)}.submission-dot.good{background:var(--good)}.submission-dot.bad{background:var(--bad)}.submission-dot.warn{background:var(--warn)}.submission-dot.pending{background:var(--gold)}.submission-summary-main{min-width:0;display:flex;flex-direction:column;gap:1px}.submission-verdict-label{font:650 13.5px Space Grotesk,sans-serif}.submission-meta,.submission-verdict-label{overflow:hidden;text-overflow:ellipsis;white-space:nowrap}.submission-runtime{white-space:nowrap;font-family:JetBrains Mono,ui-monospace,monospace}.submission-chevron{color:var(--muted);font-size:14px;text-align:center}.submission-expanded{padding:14px;border-top:1px solid var(--line);background:rgba(0,0,0,.12)}.submission-loading{display:flex;align-items:center;gap:9px;padding:5px 0}.submission-result-block{padding-bottom:14px}.submission-result-after-code{margin-top:14px;padding-top:14px;padding-bottom:0;border-top:1px solid var(--line)}.eyebrow{display:block;margin-bottom:7px;color:var(--muted);font:700 10px JetBrains Mono,ui-monospace,monospace;letter-spacing:.12em;text-transform:uppercase}.submission-code-head{display:flex;align-items:center;justify-content:space-between;gap:12px;margin-top:2px;margin-bottom:8px}.submission-code-head>div{min-width:0}.submission-code-language{display:block;margin-top:-3px}.submission-use-code{min-height:34px;padding:0 12px;white-space:nowrap;font-size:12px}.submission-code{max-height:320px;overflow:auto;margin:0;padding:13px;border:1px solid rgba(255,255,255,.055);background:#090b0f;white-space:pre;overflow-wrap:normal;-moz-tab-size:4;tab-size:4}@media (max-width:640px){.submission-history-head{align-items:center}.submission-summary{grid-template-columns:10px minmax(0,1fr) 18px}.submission-runtime{display:none}.submission-code-head{align-items:flex-start}}.statement{background:radial-gradient(circle at 12% 0,rgba(255,198,26,.035),transparent 30%),#090a0e}.statement-tabs{padding:8px 18px 0;background:rgba(9,10,14,.92);box-shadow:0 10px 30px rgba(0,0,0,.12)}.statement-tab{min-height:36px;padding:0 12px 8px;font-size:12.5px;letter-spacing:-.01em}.statement-tab-content{padding:0 0 68px}.statement-tab-content>div[role=tabpanel]{padding:22px 28px 60px}.problem-document{width:min(100%,820px);margin:0 auto;padding:26px 30px 72px}.problem-document-head{padding-bottom:28px;border-bottom:1px solid rgba(255,255,255,.085)}.problem-breadcrumb-row{display:flex;align-items:center;justify-content:space-between;gap:18px;margin-bottom:12px}.problem-back{color:rgba(242,245,250,.56);font:600 12.5px DM Sans,system-ui,sans-serif}.problem-back:hover{color:var(--text)}.problem-slug{min-width:0;overflow:hidden;text-overflow:ellipsis;white-space:nowrap;color:rgba(242,245,250,.3);font:500 10px JetBrains Mono,ui-monospace,monospace;letter-spacing:.04em}.problem-document-head h1{margin:0;font-size:clamp(27px,3vw,34px);line-height:1.16;letter-spacing:-.035em}.problem-meta{display:flex;flex-wrap:wrap;align-items:center;gap:9px 14px;margin-top:18px}.difficulty-pill{display:inline-flex;align-items:center;min-height:27px;padding:0 10px;border:1px solid rgba(255,255,255,.1);border-radius:999px;background:rgba(255,255,255,.035);font:700 9px JetBrains Mono,ui-monospace,monospace;letter-spacing:.11em;text-transform:uppercase}.difficulty-easy{color:#78e7c7;border-color:rgba(87,222,182,.25);background:rgba(87,222,182,.06)}.difficulty-medium{color:#ffe08d;border-color:rgba(255,215,107,.24);background:rgba(255,215,107,.055)}.difficulty-hard{color:#ffad99;border-color:rgba(255,155,130,.26);background:rgba(255,155,130,.055)}.meta-item{display:inline-flex;align-items:baseline;gap:6px;min-height:27px;padding-left:13px;border-left:1px solid rgba(255,255,255,.08)}.meta-item>span{color:rgba(242,245,250,.38);font:600 9px JetBrains Mono,ui-monospace,monospace;letter-spacing:.09em;text-transform:uppercase}.meta-item strong{color:rgba(242,245,250,.83);font:600 11px JetBrains Mono,ui-monospace,monospace}.problem-section{padding-top:28px}.problem-section+.problem-section{margin-top:6px;border-top:1px solid rgba(255,255,255,.06)}.problem-section-heading{display:flex;align-items:center;gap:10px;margin-bottom:14px}.problem-section-rule{width:16px;height:2px;flex:none;border-radius:999px;background:linear-gradient(90deg,var(--gold),rgba(255,198,26,.28));box-shadow:0 0 16px rgba(255,198,26,.18)}.problem-section-heading h2{margin:0;color:rgba(242,245,250,.92);font-size:16px;letter-spacing:-.018em}.problem-section-body,.prose{color:rgba(242,245,250,.76)}.prose{font-size:14.5px;line-height:1.75}.prose p{margin:0 0 13px}.prose p:last-child{margin-bottom:0}.prose strong{color:rgba(255,255,255,.96);font-weight:650}.constraint-row code,.prose code{padding:2px 6px;border:1px solid rgba(255,198,26,.14);border-radius:6px;background:rgba(255,198,26,.055);color:#ffe07d;font:500 .9em/1.5 JetBrains Mono,ui-monospace,monospace}.prose-heading{margin:18px 0 8px;color:rgba(255,255,255,.92);font:650 14px Space Grotesk,system-ui,sans-serif}.problem-list{margin:10px 0 12px;padding-left:20px}.problem-list li{margin:5px 0;padding-left:3px}.problem-list li::marker{color:rgba(255,198,26,.7)}.problem-code-block{margin:14px 0;padding:14px 16px;border:1px solid rgba(255,255,255,.07);border-radius:11px;background:#07090c;color:#e8edf5;white-space:pre;overflow:auto;overflow-wrap:normal;font:500 12.5px/1.65 JetBrains Mono,ui-monospace,monospace}.problem-code-block code{padding:0;border:0;background:transparent;color:inherit}.problem-figure{margin:20px 0 6px;overflow:hidden;border:1px solid rgba(255,255,255,.09);border-radius:15px;background:linear-gradient(180deg,rgba(255,255,255,.03),rgba(255,255,255,.015)),#0b0d12;box-shadow:0 18px 42px rgba(0,0,0,.2)}.problem-figure img{display:block;width:100%;max-height:520px;object-fit:contain;background:#08090d}.problem-figure figcaption{padding:9px 12px 10px;border-top:1px solid rgba(255,255,255,.06);color:rgba(242,245,250,.46);font-size:11.5px;text-align:center}.constraint-list{overflow:hidden;border:1px solid rgba(255,255,255,.075);border-radius:12px;background:rgba(255,255,255,.018)}.constraint-row{display:grid;grid-template-columns:10px minmax(0,1fr);grid-gap:10px;gap:10px;align-items:start;padding:10px 13px;color:rgba(242,245,250,.76);font:500 12.5px/1.65 JetBrains Mono,ui-monospace,monospace}.constraint-row+.constraint-row{border-top:1px solid rgba(255,255,255,.05)}.constraint-mark{width:4px;height:4px;margin-top:8px;border-radius:50%;background:var(--gold);box-shadow:0 0 9px rgba(255,198,26,.32)}.samples-list{display:grid;grid-gap:14px;gap:14px}.sample-card{overflow:hidden;border:1px solid rgba(255,255,255,.08);border-radius:13px;background:#0a0c10;box-shadow:inset 0 1px rgba(255,255,255,.025)}.sample-card-head{display:flex;align-items:center;min-height:35px;padding:0 13px;border-bottom:1px solid rgba(255,255,255,.06);background:rgba(255,255,255,.018)}.sample-card-head span,.sample-label,.sample-note>span{color:rgba(242,245,250,.44);font:700 9px JetBrains Mono,ui-monospace,monospace;letter-spacing:.12em;text-transform:uppercase}.sample-grid{display:grid;grid-template-columns:1fr 1fr}.sample-pane{min-width:0;padding:12px 13px 14px}.sample-pane+.sample-pane{border-left:1px solid rgba(255,255,255,.055)}.sample-pane pre{margin:6px 0 0;padding:0;border-radius:0;background:transparent;color:rgba(245,248,252,.92);white-space:pre;overflow:auto;overflow-wrap:normal;font:500 12.5px/1.6 JetBrains Mono,ui-monospace,monospace}.sample-note{padding:11px 13px 13px;border-top:1px solid rgba(255,255,255,.055);background:rgba(255,255,255,.012)}.sample-note .prose{margin-top:5px;font-size:13px}@media (max-width:900px){.statement-tab-content{padding-bottom:0}.statement-tab-content>div[role=tabpanel]{padding:18px 18px 44px}.problem-document{padding:22px 20px 52px}}@media (max-width:620px){.problem-document{padding-inline:16px}.problem-document-head h1{font-size:26px}.problem-meta{gap:8px 10px}.meta-item{padding-left:10px}.sample-grid{grid-template-columns:1fr}.sample-pane+.sample-pane{border-left:0;border-top:1px solid rgba(255,255,255,.055)}.problem-figure{border-radius:12px}}