body {
    background: #1d3557;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    font-family: Arial;
}

.container {
    background: white;
    padding: 25px;
    width: 350px;
    border-radius: 10px;
    text-align: center;
}

input {
    width: 100%;
    height: 40px;
    margin-bottom: 15px;
    padding: 8px;
}

button {
    width: 100%;
    height: 40px;
    background: #457b9d;
    color: white;
    border: none;
    cursor: pointer;
}

#imgBox {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.5s;
    margin-top: 10px;
}

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

@keyframes shake {
    0% { transform: translateX(0); }
    25% { transform: translateX(-2px); }
    50% { transform: translateX(0); }
    75% { transform: translateX(2px); }
    100% { transform: translateX(0); }
}

.error {
    animation: shake 0.1s linear 10;
    border: 1px solid red;
}