body {
    font-family: Arial, sans-serif;
    background: #f5f5f5;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
}

.container {
    background: white;
    padding: 20px;
    border-radius: 8px;
    box-shadow: 0px 0px 10px rgba(0, 0, 0, 0.1);
    text-align: center;
    width: 300px;
}

input, button {
    width: 100%;
    padding: 8px;
    margin: 5px 0;
    border: 1px solid #ddd;
    border-radius: 5px;
}

button {
    background: #3498db;
    color: white;
    cursor: pointer;
}

button:hover {
    background: #2980b9;
}

.receipt {
    margin-top: 20px;
    padding: 10px;
    border: 1px solid #ddd;
    text-align: left;
    background: #fff;
}

.error {
    color: red;
    margin-top: 10px;
}