:root{--primary: #1e40af;--primary-dark: #1e3a8a;--accent: #f59e0b;--success: #10b981;--danger: #ef4444;--surface: #ffffff;--background: #f8fafc;--text: #1e293b;--text-muted: #64748b}*{margin:0;padding:0;box-sizing:border-box}body{font-family:Inter,-apple-system,BlinkMacSystemFont,sans-serif;background:linear-gradient(135deg,#0f172a,#1e293b);min-height:100vh;color:var(--text)}.card{background:var(--surface);border-radius:16px;box-shadow:0 4px 6px -1px #0000001a,0 2px 4px -1px #0000000f;padding:1.5rem;transition:transform .2s ease,box-shadow .2s ease}.card:hover{transform:translateY(-2px);box-shadow:0 10px 15px -3px #0000001a,0 4px 6px -2px #0000000d}.btn-primary{background:linear-gradient(135deg,var(--primary) 0%,var(--primary-dark) 100%);color:#fff;padding:.75rem 1.5rem;border-radius:8px;font-weight:600;border:none;cursor:pointer;transition:all .2s ease}.btn-primary:hover{transform:scale(1.02);box-shadow:0 4px 12px #1e40af66}.btn-primary:disabled{opacity:.5;cursor:not-allowed;transform:none}.progress-bar{height:8px;background:#e2e8f0;border-radius:4px;overflow:hidden}.progress-fill{height:100%;background:linear-gradient(90deg,var(--primary) 0%,var(--accent) 100%);transition:width .3s ease}.quiz-option{background:#f8fafc;border:2px solid #e2e8f0;border-radius:12px;padding:1rem 1.25rem;cursor:pointer;transition:all .2s ease}.quiz-option:hover{border-color:var(--primary);background:#eff6ff}.quiz-option.selected{border-color:var(--primary);background:#dbeafe}.quiz-option.correct{border-color:var(--success);background:#d1fae5}.quiz-option.incorrect{border-color:var(--danger);background:#fee2e2}.score-ring{width:120px;height:120px;border-radius:50%;background:conic-gradient(var(--primary) var(--progress),#e2e8f0 0);display:flex;align-items:center;justify-content:center;position:relative}.score-ring:before{content:"";position:absolute;width:100px;height:100px;background:#fff;border-radius:50%}.score-ring span{position:relative;z-index:1;font-size:1.5rem;font-weight:700;color:var(--primary)}@keyframes pulse{0%,to{opacity:1}50%{opacity:.5}}.loading{animation:pulse 2s infinite}.category-card{background:linear-gradient(135deg,var(--primary) 0%,var(--primary-dark) 100%);color:#fff;border-radius:16px;padding:1.5rem;cursor:pointer;transition:all .3s ease}.category-card:hover{transform:translateY(-4px) scale(1.02);box-shadow:0 20px 25px -5px #0003}.badge-beginner{background:#10b981;color:#fff}.badge-intermediate{background:#f59e0b;color:#fff}.badge-advanced{background:#ef4444;color:#fff}.badge-expert{background:#8b5cf6;color:#fff}.badge{padding:.25rem .75rem;border-radius:9999px;font-size:.75rem;font-weight:600;text-transform:uppercase}@media(max-width:768px){.card{padding:1rem}.btn-primary{width:100%}}