* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Helvetica Neue', sans-serif;
}

body {
    background: #e9ecef;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    margin: 0;
}

.container {
    width: 100%;
    max-width: 360px;
    padding: 20px;
    background: #ffffff;
    border-radius: 8px;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
    text-align: center;
}

.container h1 {
    font-size: 22px;
    color: #333;
    margin-bottom: 20px;
}

.container p {
    font-size: 14px;
    color: #666;
    margin-bottom: 12px;
}

.container input {
    width: 100%;
    padding: 12px;
    margin: 10px 0 20px;
    border: 1px solid #ced4da;
    border-radius: 5px;
    font-size: 16px;
    transition: border 0.3s;
}

.container input:focus {
    border-color: #007bff;
}

.container button {
    width: 100%;
    padding: 12px;
    background: #007bff;
    color: #fff;
    border: none;
    border-radius: 5px;
    font-size: 16px;
    cursor: pointer;
    transition: background 0.3s, transform 0.3s;
    margin-bottom: 10px;
}

.container button:hover {
    background: #0056b3;
    transform: translateY(-2px);
}

#imgBox {
    width: 100%;
    max-width: 200px;
    margin: 20px auto 0;
    border-radius: 5px;
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.5s ease-in-out;
}

#imgBox img {
    width: 100%;
    padding: 10px;
}

#imgBox.show-img {
    max-height: 300px;
}

.error {
    animation: shake 0.2s ease-in-out 2;
    border-color: #ff0000;
}

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

@media (max-width: 480px) {
    .container {
        padding: 15px;
    }

    .container h1 {
        font-size: 20px;
    }

    .container input, .container button {
        font-size: 14px;
    }
}