body{
    font-family: Arial, sans-serif;
    background: #f8f8f8;
    margin: 0;
    padding: 0;
}
.container{
    max-width: 500px;
    margin: 50px auto;
    padding: 20px;
    background: #fff;
    border-radius: 8px;
    box-shadow: 0 0 10px rgba(0,0,0,0.1);
}
input[type=number]{
    width: calc(100% - 20px);
    padding: 10px;
    margin-bottom: 10px;
}
button{
    padding: 10px 20px;
    background: #007bff;
    color: #fff;
    border: none;
    border-radius: 4px;
    cursor: pointer;
}
button:hover{
    background: #0056b3;
}
.error{
    color: red;
}
.order-details{
    margin-top: 20px;
    padding: 15px;
    background: #f1f1f1;
    border-radius: 6px;
}