:root{--ink:#17364f;--blue:#0c64a6;--dark:#10456f;--line:#c7e0f4;--soft:#eaf6ff;--bg:#f5faff}*{box-sizing:border-box}body{margin:0;font:16px/1.7 system-ui,-apple-system,"Segoe UI",Arial,sans-serif;background:var(--bg);color:var(--ink)}a{color:#0863a8}main{max-width:1100px;margin:0 auto;padding:28px 20px 80px}.course-hero{background:linear-gradient(125deg,#d6eeff,#f6fbff);border:1px solid var(--line);padding:38px;border-radius:22px;box-shadow:0 14px 35px #0e5b8f12}.eyebrow,.step-label{font-size:.82rem;letter-spacing:.1em;text-transform:uppercase;color:#176ca8;font-weight:850}h1{font-size:clamp(2rem,5vw,3.3rem);line-height:1.15;margin:8px 0;color:var(--dark)}h2{color:#0e558b;line-height:1.25;margin:.3em 0 .55em}h3{color:#135b92}.lead{font-size:1.15rem;max-width:820px;margin-bottom:12px}.meta{color:#4f6982}.course-nav,.actions{display:flex;gap:10px;flex-wrap:wrap;margin:18px 0}.course-nav a,.actions a{display:inline-block;text-decoration:none;border:1px solid #a7d0ed;border-radius:12px;background:white;color:#075995;padding:9px 14px;font-weight:750}.course-nav a[aria-current],.actions a.primary{background:#0c66a9;color:white;border-color:#0c66a9}.lesson-panel,.roadmap,.challenge,.resource,.start-grid>a{background:white;border:1px solid var(--line);padding:25px;border-radius:18px;margin:20px 0;box-shadow:0 7px 25px #0e5b8f0b}.lesson-panel p:first-of-type{margin-top:0}.example{border:1px solid #bed8ee;border-radius:14px;overflow:hidden;margin:16px 0}.example-bar{display:flex;justify-content:space-between;align-items:center;gap:12px;background:#e3f1fc;padding:9px 12px;font-size:.82rem;font-weight:800;color:#164e78}.example-bar button{padding:5px 11px;border:1px solid #85b9df;border-radius:8px;background:white;color:#0c5790;font:inherit;cursor:pointer}.example pre{white-space:pre;overflow:auto;background:#102638;color:#f5fcff;margin:0;padding:19px;font:14px/1.65 Consolas,Monaco,monospace}.tip{background:#edf9ff;border-left:4px solid #1682ca;padding:12px 15px;border-radius:8px}.challenge{background:#f6fbff}.challenge details{margin:12px 0}.challenge summary{cursor:pointer;color:#095a99;font-weight:800}.start-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:16px;margin-top:20px}.start-grid>a{display:block;text-decoration:none;color:inherit;margin:0}.start-grid>a:hover{border-color:#579ecd;transform:translateY(-2px)}.start-grid strong{display:block;color:#105d97;font-size:1.1rem}.start-grid small{display:block;color:#557289;margin-top:8px}.roadmap ol{padding-left:25px}.roadmap li{margin:7px 0}.roadmap .future{color:#637b90}.responsive-table{overflow-x:auto}.responsive-table table{width:100%;border-collapse:collapse;background:white;min-width:520px}.responsive-table th,.responsive-table td{border:1px solid var(--line);padding:8px 12px;text-align:left}.responsive-table th{background:#e1f1ff}.resource{background:#e9f6ff}.resource ul{margin:0}.checkpoint{border-left:4px solid #0c7dbc;padding-left:17px}.muted{color:#59718a}.callout{border-radius:13px;background:#fff5de;border:1px solid #ead09a;padding:16px}.footer-note{font-size:.9rem;color:#59718a;margin:30px 0}@media(max-width:720px){main{padding:18px 12px 60px}.course-hero{padding:22px}.lesson-panel,.roadmap,.challenge,.resource{padding:18px}.start-grid{grid-template-columns:1fr}.example pre{font-size:12.5px;padding:14px}}