website/web/static/css/theme-purple.css

:root {
    --bulma-primary-h: 292deg;
    --bulma-primary-l: 60%;
    --bulma-link-h: 277deg;
    --bulma-link-l: 45%;
    --bulma-scheme-h: 293;
    --bulma-scheme-s: 23%;
}

/*
 * Forum Colors: with all the nested boxes, Bulma's default color scheme is
 * too limited for a good experience.
 */
 .nonshy-forum-box-1 {
    /* Outermost box: Forum or Thread top-level wrappers */
    background-color: #f4d1ff;
}
.nonshy-forum-box-2 {
    /* Nested box: "Latest Post" on Forum-level views */
    background-color: #f1d0ef;
}
.nonshy-forum-box-3 {
    /* Nested box: Topics/Posts/Users/View counters */
    background-color: #d7c2ff;
}