body {
    font-family: Arial, sans-serif;
    background-color: #f0f8ff;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
}

#form-container {
    background-color: #ffffff;
    padding: 20px;
    border-radius: 10px;
    box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
}

form {
    display: flex;
    flex-direction: column;
}

label {
    margin-top: 10px;
    font-weight: bold;
}

input {
    padding: 10px;
    margin-top: 5px;
    border: 2px solid #cccccc;
    border-radius: 5px;
    font-size: 16px;
    transition: border-color 0.3s;
}

input:focus {
    border-color: #66afe9;
    outline: none;
    box-shadow: 0 0 8px rgba(102, 175, 233, 0.6);
}

button {
    margin-top: 20px;
    padding: 10px;
    background-color: #4CAF50;
    color: white;
    border: none;
    border-radius: 5px;
    font-size: 16px;
    cursor: pointer;
    transition: background-color 0.3s;
}

button:hover {
    background-color: #45a049;
}

.error {
    color: red;
    margin-top: 5px;
    font-size: 14px;
}

.shake {
    animation: shake 0.5s;
    border-color: red;
}

@keyframes shake {
    0% { transform: translateX(0); }
    25% { transform: translateX(-5px); }
    50% { transform: translateX(5px); }
    75% { transform: translateX(-5px); }
    100% { transform: translateX(0); }
}