:root{--ink:#111629;--blue:#4c7dff;--cyan:#22d3ee;--mut:#5a6180;--bg:#f6f8ff}
*{box-sizing:border-box}body{margin:0;font:15px/1.5 system-ui,-apple-system,Segoe UI,Inter,sans-serif;color:var(--ink);background:var(--bg)}
header{display:flex;justify-content:space-between;align-items:center;padding:14px 24px;background:var(--ink);color:#fff;border-bottom:3px solid var(--blue)}
.brand{font-weight:700;letter-spacing:.3px}#who{color:#c3c8dc;font-size:13px}
main{max-width:980px;margin:28px auto;padding:0 20px}h1{font-size:24px;margin:0 0 10px}h2{font-size:17px;margin:26px 0 8px}h3{font-size:14px;margin:0 0 6px}
input,textarea{width:100%;font:13px ui-monospace,Menlo,monospace;padding:9px;border:1px solid #c3c8dc;border-radius:6px;background:#fff}
input{font-size:15px;margin:6px 0 12px}textarea{height:260px}
button{background:var(--blue);color:#fff;border:0;border-radius:6px;padding:9px 16px;font-size:14px;cursor:pointer;margin-top:8px}button.secondary{background:#8b93b0}
.msg{min-height:1.4em;font-size:14px}.msg.err{color:#c0392b}.msg.ok{color:#1a7a40}.small{color:var(--mut);font-size:13px}
.facts{display:flex;gap:18px;flex-wrap:wrap;font-size:14px;color:var(--mut)}.facts b{color:var(--ink)}
table{width:100%;border-collapse:collapse;font-size:13px;background:#fff}th{background:var(--ink);color:#fff;text-align:left;padding:7px}td{padding:7px;border-bottom:1px solid #e4e8ec}
.halves{display:grid;grid-template-columns:1fr 1fr;gap:18px}@media(max-width:760px){.halves{grid-template-columns:1fr}}
pre.example{background:#eef2ff;border-left:3px solid var(--blue);padding:10px;font-size:12px;overflow:auto}code{background:#eef2ff;padding:1px 4px;border-radius:3px}