.collapsible {
    background: transparent;
    cursor: pointer;
    padding: 10px;
    width: 100%;
    border: none;
    text-align: center;
    outline: none;
    font-size: 20px;
}

.active, .collapsible:hover {
    background-color: #27ae60;
    color:white;
}

.collapsible:after {
    content: '\002B';
    font-weight: bold;
    float: right;
    margin-left: 5px;
}

.active:after {
    content: "\2212";
}

.content {
    padding: 0 18px;
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.2s ease-out;
    background-color: #f1f1f1;
}