找到网站xiunobbs 站点中的/view/css/bootstrap-bbs.css，然后在合适的位置(适合的位置...自己思考)插入如下代码：

/* H6标题 */
.card-body .message h6 {
border-left: 3px solid #6293d4;
text-indent: 8px;
font-weight: bold;
padding: 2px 0px;
margin: 8px 0px;
}
/* H5标题 */
.card-body .message h5 {
border-left: 4px solid #84985a;
text-indent: 8px;
font-weight: bold;
padding: 2px 0px;
margin: 8px 0px;
}
/* H4标题 */
.card-body .message h4 {
border-left: 5px solid #b55594;
text-indent: 8px;
font-weight: bold;
padding: 2px 0px;
margin: 8px 0px;
}
/* H3标题 */
.card-body .message h3 {
border-left: 6px solid #a232de;
text-indent: 8px;
font-weight: bold;
padding: 2px 0px;
margin: 8px 0px;
}
/* H2标题 */
.card-body .message h2 {
border-left: 7px solid #32de5d;
text-indent: 8px;
font-weight: bold;
padding: 2px 0px;
margin: 8px 0px;
}
/* H1标题 */
.card-body .message h1 {
border-left: 8px solid #de3232;
text-indent: 8px;
font-weight: bold;
padding: 2px 0px;
margin: 8px 0px;
}