bookstack/resources/assets/sass/_comments.scss

.comment-box {
    border: 1px solid #DDD;
    margin-bottom: $-s;
    border-radius: 3px;
    .content {
        padding: $-s;
    }
    .content p {
        margin-bottom: 1em;
    }
}

.comment-box .header {
    padding: $-xs $-s;
    background-color: #f8f8f8;
    border-bottom: 1px solid #DDD;
    img, a, span {
        display: inline-block;
        vertical-align: top;
    }
    a, span {
        padding: $-xxs 0 $-xxs 0;
        line-height: 1.6;
    }
    a { color: #666; }
    span {
        color: #888;
        padding-left: $-xxs;
    }
    .text-muted {
        color: #999;
    }
}