:root{--bg-start: #0f172a;--bg-end: #1e293b;--card-bg: #1e293b;--card-border: #334155;--surface: #0f172a;--text-primary: #f1f5f9;--text-secondary: #94a3b8;--text-muted: #64748b;--accent: #38bdf8;--accent-glow: rgba(56, 189, 248, .15);--correct: #4ade80;--correct-bg: rgba(74, 222, 128, .1);--incorrect: #f87171;--incorrect-bg: rgba(248, 113, 113, .1);--tone1: #f87171;--tone2: #fbbf24;--tone3: #4ade80;--tone4: #60a5fa;--radius: 16px;--radius-sm: 10px;--shadow: 0 4px 24px rgba(0, 0, 0, .3)}*{margin:0;padding:0;box-sizing:border-box}body{font-family:DM Sans,Noto Sans SC,sans-serif;background:linear-gradient(160deg,var(--bg-start),var(--bg-end));min-height:100vh;color:var(--text-primary);overflow-x:hidden}body:before{content:"";position:fixed;top:-40%;left:-20%;width:60%;height:80%;background:radial-gradient(circle,rgba(56,189,248,.06) 0%,transparent 70%);pointer-events:none;z-index:0}.app-shell{position:relative;z-index:1;max-width:640px;margin:0 auto;padding:24px 16px 48px}.badge{display:inline-block;padding:4px 14px;background:var(--accent-glow);border:1px solid rgba(56,189,248,.25);border-radius:20px;font-size:.75rem;font-weight:500;color:var(--accent);letter-spacing:.06em;text-transform:uppercase}.card{background:var(--card-bg);border:1px solid var(--card-border);border-radius:var(--radius);padding:32px 24px;box-shadow:var(--shadow)}.btn{display:inline-flex;align-items:center;justify-content:center;gap:6px;padding:14px 24px;border:none;border-radius:var(--radius-sm);font-family:inherit;font-size:.95rem;font-weight:600;cursor:pointer;transition:all .2s ease}.btn:hover{transform:translateY(-2px)}.btn-primary{background:var(--accent);color:#0c1424}.btn-primary:hover{box-shadow:0 8px 24px #38bdf84d}.btn-secondary{background:var(--surface);border:1px solid var(--card-border);color:var(--text-primary)}.btn-lg{padding:16px 48px;font-size:1.05rem;font-weight:700}@keyframes cardIn{0%{opacity:0;transform:translateY(16px) scale(.97)}to{opacity:1;transform:translateY(0) scale(1)}}@keyframes pulse-ring{0%{box-shadow:0 0 #38bdf866}to{box-shadow:0 0 0 24px #38bdf800}}.animate-in{animation:cardIn .4s ease-out}.feedback-toast{position:fixed;top:20px;left:50%;transform:translate(-50%) translateY(-80px);padding:12px 28px;border-radius:40px;font-weight:600;font-size:.95rem;z-index:100;pointer-events:none;opacity:0;transition:all .35s cubic-bezier(.22,1,.36,1);white-space:nowrap}.feedback-toast.show{opacity:1;transform:translate(-50%) translateY(0)}.feedback-toast.correct{background:var(--correct);color:#052e16}.feedback-toast.incorrect{background:var(--incorrect);color:#450a0a}.hidden{display:none!important}.text-center{text-align:center}@media(max-width:480px){.app-shell{padding:16px 12px 40px}.card{padding:24px 16px}}