@keyframes fadeIn {
            from { opacity: 0; transform: translateY(20px); }
            to { opacity: 1; transform: translateY(0); }
        }
        .fade-in { animation: fadeIn 0.5s ease-out; }
        .gradient-bg { background: linear-gradient(135deg, #667eea 0%, #764ba2 100%); }
        .input-focus:focus { border-color: #667eea; box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.1); }
        .btn-hover:hover { transform: translateY(-2px); box-shadow: 0 10px 20px rgba(102, 126, 234, 0.3); }
        .page { display: none; }
        .page.active { display: block; }
        .otp-input { width: 3rem; height: 3rem; text-align: center; font-size: 1.5rem; }
        .strength-weak { background: #ef4444; }
        .strength-medium { background: #f59e0b; }
        .strength-strong { background: #10b981; }