.fade-in {
            animation: fadeIn 0.5s ease-in;
        }
        .shake {
            animation: shake 0.3s ease-in-out;
        }
        @keyframes fadeIn {
            from { opacity: 0; transform: translateY(10px); }
            to { opacity: 1; transform: translateY(0); }
        }
        @keyframes shake {
            0%, 100% { transform: translateX(0); }
            25% { transform: translateX(-5px); }
            75% { transform: translateX(5px); }
        }
        .toggle-password {
            cursor: pointer;
            position: absolute;
            right: 10px;
            top: 50%;
            transform: translateY(-50%);
        }