*{box-sizing:border-box;margin:0;padding:0;font-family:Segoe UI,Roboto,Helvetica,Arial,sans-serif}body{color:#333;background-color:#eef2f6;padding:20px 10px}.quiz-container{background:#fff;border-radius:16px;max-width:1100px;margin:0 auto;padding:40px;box-shadow:0 10px 30px #00000014}.header{border-bottom:2px solid #f0f0f0;flex-wrap:wrap;justify-content:space-between;align-items:center;gap:15px;margin-bottom:30px;padding-bottom:20px;display:flex}.header h1{color:#1a237e;font-size:2.2rem;font-weight:800}.score-display{color:#c62828;background:#ffebee;border:1px solid #ffcdd2;border-radius:50px;padding:10px 24px;font-size:1.1rem;font-weight:700}.grid-layout{grid-template-columns:7fr 3fr;gap:40px;display:grid}.main-panel{border-right:1px solid #eee;padding-right:20px}.question-header h2{color:#666;margin-bottom:10px;font-size:1.1rem;font-weight:400}.question-text{color:#111;margin-bottom:30px;font-size:1.35rem;font-weight:700;line-height:1.5}.options-list{flex-direction:column;gap:12px;display:flex}.option-btn{color:#333;text-align:left;cursor:pointer;background-color:#fff;border:2px solid #e0e0e0;border-radius:12px;width:100%;padding:16px 20px;font-size:1.1rem;font-weight:500;line-height:1.4;transition:all .2s}.option-btn:hover:not(:disabled){background-color:#f8fbff;border-color:#90caf9}.option-btn.selected{color:#0d47a1;background-color:#e3f2fd;border-color:#2196f3;font-weight:700}.option-btn.correct{color:#1b5e20;background-color:#e8f5e9;border-color:#4caf50;font-weight:700}.option-btn.wrong{color:#b71c1c;background-color:#ffebee;border-color:#f44336;font-weight:700;text-decoration:line-through}.option-btn.disabled{opacity:.5;cursor:not-allowed;background-color:#f5f5f5}.rationale-box{color:#1b5e20;background:#e8f5e9;border-left:6px solid #4caf50;border-radius:0 8px 8px 0;margin-top:25px;padding:20px;font-size:1.05rem;line-height:1.6}.nav-buttons{justify-content:space-between;gap:15px;margin-top:30px;display:flex}.nav-buttons button{color:#455a64;cursor:pointer;background:#eceff1;border:none;border-radius:8px;flex:1;padding:12px 25px;font-size:1rem;font-weight:700;transition:all .2s}.nav-buttons button:hover:not(:disabled){background:#cfd8dc}.nav-buttons button:disabled{opacity:.4;cursor:not-allowed}.side-panel{background:#fafafa;border:1px solid #eee;border-radius:12px;flex-direction:column;height:fit-content;padding:25px;display:flex}.side-panel h3{color:#444;text-align:center;margin-bottom:20px;font-size:1.2rem}.nav-grid{grid-template-columns:repeat(5,1fr);gap:10px;display:grid}.nav-cell{aspect-ratio:1;color:#555;cursor:pointer;background:#fff;border:2px solid #ddd;border-radius:8px;justify-content:center;align-items:center;padding:0;font-size:1rem;font-weight:700;transition:all .2s;display:flex}.nav-cell:hover{background:#f0f0f0}.nav-cell.active{border-color:#2196f3;box-shadow:0 0 0 3px #2196f333}.nav-cell.answered{color:#fff;background:#2196f3;border-color:#1976d2}.nav-cell.review-correct{color:#fff;background:#4caf50;border-color:#388e3c}.nav-cell.review-wrong{color:#fff;background:#f44336;border-color:#d32f2f}.nav-cell.review-skipped{color:#fff;background:#9e9e9e;border-color:#757575}.panel-actions{margin-top:30px}.submit-btn,.reset-btn{color:#fff;cursor:pointer;text-transform:uppercase;letter-spacing:.5px;border:none;border-radius:8px;width:100%;padding:16px;font-size:1.1rem;font-weight:700;transition:all .2s}.submit-btn{background:#2196f3;box-shadow:0 4px 10px #2196f34d}.submit-btn:hover{background:#1976d2}.reset-btn{background:#ff9800;box-shadow:0 4px 10px #ff98004d}.reset-btn:hover{background:#f57c00}.welcome-screen{justify-content:center;align-items:center;min-height:80vh;display:flex}.welcome-card{text-align:center;background:#fff;border-radius:16px;max-width:600px;padding:40px;box-shadow:0 10px 40px #0000001a}.welcome-card h1{color:#1a237e;margin-bottom:20px;font-size:2rem}.welcome-card p{color:#555;margin-bottom:25px;font-size:1.1rem;line-height:1.6}.welcome-card ul{text-align:left;background:#f8fbff;border:1px solid #e3f2fd;border-radius:12px;margin-bottom:30px;padding:20px;list-style:none}.welcome-card ul li{color:#333;margin-bottom:10px;font-size:1rem;line-height:1.5}.start-btn{color:#fff;cursor:pointer;text-transform:uppercase;background:#4caf50;border:none;border-radius:50px;padding:16px 35px;font-size:1.2rem;font-weight:700;transition:all .3s;box-shadow:0 6px 15px #4caf5066}.start-btn:hover{background:#388e3c;transform:translateY(-2px);box-shadow:0 8px 20px #4caf5080}@media (width<=900px){.grid-layout{flex-direction:column;gap:30px;display:flex}.main-panel{border-bottom:2px solid #eee;border-right:none;padding-bottom:30px;padding-right:0}}@media (width<=600px){.quiz-container{border-radius:12px;padding:20px 15px}.header h1{font-size:1.6rem}.question-text{font-size:1.15rem}.option-btn{padding:14px 16px;font-size:1rem}.side-panel{padding:15px}.nav-grid{gap:8px}.nav-cell{border-radius:6px;font-size:.9rem}.welcome-card{padding:25px 15px}.welcome-card h1{font-size:1.5rem}.start-btn{width:100%;padding:15px 20px;font-size:1.1rem}}