body {
    font-family: Arial;
    max-width: 800px;
    margin: 40px auto;
    background: linear-gradient(to bottom, #e6f3ff, #ffffff);
}

.seat {
    width: 60px;
    height: 60px;
    margin: 5px;
    display: inline-block;
    text-align: center;
    line-height: 60px;
    background: lightgreen;
    cursor: pointer;
    border-radius: 6px;
}

.reserved {
    background: crimson;
    color: white;
}

.row {
    margin-bottom: 10px;
}

.gap {
    display: inline-block;
    width: 30px;
}

#receipt {
    margin-top: 20px;
    padding: 15px;
    background: #e8ffe8;
    border-radius: 8px;
}