:root{color-scheme:dark;--background:#07111f;--card:rgba(13,29,49,0.82);--border:rgba(148,163,184,0.2);--text:#f8fafc;--muted:#a8b5c7;--accent:#38bdf8}*{box-sizing:border-box}body{margin:0;color:var(--text);background:radial-gradient(circle at 20% 20%,rgba(14,165,233,.18),transparent 36%),radial-gradient(circle at 80% 75%,rgba(99,102,241,.16),transparent 34%),var(--background);font-family:Arial,Helvetica,sans-serif}main{display:grid;min-height:100vh;place-items:center;padding:24px}.card{width:min(680px,100%);padding:clamp(32px,7vw,64px);border:1px solid var(--border);border-radius:28px;background:var(--card);box-shadow:0 32px 80px rgba(0,0,0,.35);-webkit-backdrop-filter:blur(18px);backdrop-filter:blur(18px)}.eyebrow{margin:0 0 18px;color:var(--accent);font-size:.78rem;font-weight:700;letter-spacing:.16em}h1{margin:0;font-size:clamp(2.3rem,7vw,4.5rem);line-height:.98;letter-spacing:-.06em}.course-name{display:block;margin-top:20px;color:var(--accent);font-size:clamp(1.25rem,3vw,1.8rem);line-height:1.2;letter-spacing:-.02em}.intro{margin:26px 0;color:var(--muted);font-size:1.08rem;line-height:1.65}.status{display:flex;align-items:center;min-height:52px;margin-bottom:20px;padding:14px 16px;border:1px solid var(--border);border-radius:14px;background:rgba(2,8,23,.42);gap:12px}.dot{width:9px;height:9px;flex:0 0 auto;border-radius:50%;background:#4ade80;box-shadow:0 0 18px #4ade80}button{width:100%;padding:15px 20px;border:0;border-radius:14px;color:#00131f;background:var(--accent);cursor:pointer;font-size:1rem;font-weight:700}button:disabled{cursor:wait;opacity:.65}button:focus-visible{outline:3px solid white;outline-offset:3px}