details.faq-category summary {
    list-style: none;
    cursor: pointer;

    font-size: 1.4em;
    font-weight: bold;

    padding: 0.7em;
    text-align: center;

    background-color: #FFFFF;
    border: 1px solid #DDDDDD;
}

details.faq-category summary {

    background-color:#FFFFFF;
    border:1px solid #DDDDDD;

}

/* 開いている時 */
details[open] summary {

    background-color:#F7F7F7;

}

/* 標準の▶を消す */
details.faq-category summary::-webkit-details-marker {
    display: none;
}

details.faq-category summary::marker {
    display: none;
}

/* ＋表示 */
.accordion-icon::before {
    content: "+";
    font-weight: bold;
    color: #666;
    margin-left: 0.3em;
}

/* 開いたら－表示 */
details[open] .accordion-icon::before {
    content: "−";
}