.option-btn{background:#f5f5f5;border:2px solid #e0e0e0;border-radius:20px;padding:15px 20px;text-align:center;cursor:pointer;transition:all .3s;font-size:1rem;font-weight:500;color:#555}.option-btn:hover{background:#e8e8ff;border-color:#667eea;transform:translateY(-2px)}.option-btn.selected{background:linear-gradient(135deg,#667eea,#764ba2);color:white;border-color:transparent}.option-btn.correct{background:#4caf50;color:white;border-color:transparent}.option-btn.wrong{background:#f44336;color:white;border-color:transparent}