.collapsible {
    background-color: #444;
    color: white;
    cursor: pointer;
    padding: 18px;
    margin-bottom: 25px;
    width: 100%;
    border: none;
    text-align: left;
    outline: none;
    font-size: 15px;
}

.active, .collapsible:hover {
    background-color: #555;
}

.content1 {
    padding: 0 18px;
    padding-bottom: 18px;
    display: none;
    overflow: hidden;
    background-color: white;
    text-align: center;
}