:root{color-scheme:dark;font-family:Inter,system-ui,sans-serif;--bg:#08090b;--panel:#14161a;--line:#30343b;--text:#f5f2ed;--muted:#a9a6a1;--red:#e21d38;--green:#6bd6a0}*{box-sizing:border-box}body{margin:0;background:var(--bg);color:var(--text);line-height:1.55}header,main,footer{max-width:1040px;margin:auto;padding:24px}header{display:flex;justify-content:space-between;border-bottom:1px solid var(--line)}a{color:inherit}.brand{text-decoration:none}.brand strong{letter-spacing:.1em}.eyebrow{color:var(--red);text-transform:uppercase;letter-spacing:.14em;font-size:.74rem}h1{font-size:clamp(2.5rem,7vw,5.8rem);line-height:.94;letter-spacing:-.055em;margin:64px 0 24px;overflow-wrap:anywhere}.lead{font-size:1.2rem;color:var(--muted);max-width:760px}.grid{display:grid;grid-template-columns:1fr 1fr;gap:20px;margin:48px 0}.panel{border:1px solid var(--line);background:var(--panel);padding:24px}.step{display:grid;grid-template-columns:42px 1fr;gap:12px;padding:14px 0;border-bottom:1px solid var(--line)}.step b{color:var(--red)}textarea{width:100%;min-height:250px;background:#0b0c0e;color:var(--text);border:1px solid var(--line);padding:15px;font:14px ui-monospace,monospace}button{background:var(--red);color:white;border:0;padding:12px 18px;font:inherit;font-weight:700;margin-top:12px;cursor:pointer}.result{padding:12px;border-left:3px solid var(--line)}.pass{border-color:var(--green)}.fail{border-color:var(--red)}footer{border-top:1px solid var(--line);color:var(--muted)}@media(max-width:700px){header,main,footer{padding:20px}.grid{grid-template-columns:1fr}h1{font-size:clamp(2.2rem,13vw,4rem);margin-top:44px}}