body {
    font-family: Arial, Helvetica, sans-serif;
}

table,
td {
    border: 1px solid black;
}

.sel {
    padding: 5px
}

canvas {
    outline: 2px solid black;
}

.container {
    width: 200px;
}

.collapsible {
    background-color: #ccc;
    cursor: pointer;
    padding: 18px;
    width: 100%;
    border: none;
    text-align: left;
    outline: none;
    font-size: 15px;
}

.active,
.collapsible:hover {
    background-color: #ddd;
}

.content {
    padding: 0px 0px;
    display: none;
    overflow: hidden;
    background-color: #f1f1f1;
}