summary {
    position: relative;
    list-style: none;
}

/* remove default arrow */
summary::marker {
    content: "";
}

/* default = PLUS */
summary::after {
    content: "\f067"; /* fa-plus */
    font-family: "Font Awesome 6 Free";
    font-weight: 900;

    position: absolute;
    right: 0;
    top: 50%;
    transform: translateY(-50%);
}

/* when open = MINUS */
details[open] summary::after {
    content: "\f068"; /* fa-minus */
}