Add tags.css to vault/.obsidian/snippets/ and then activate in Obsidian > Settings > Appearance

tags.css

.cm-tag-new,
.cm-tag-added,
.cm-tag-changed,
.cm-tag-deprecated,
.cm-tag-removed,
.cm-tag-fixed,
.cm-tag-security,
.cm-tag-meeting,
.cm-tag-support {
    position: relative;
    top: -2px;
    border: 0!important;
    background: #6A7082;
    font-size: 0.7rem;
    text-transform: uppercase;
    color: white;
    padding-top: 2px;
    padding-bottom: 1.5px;
    font-weight: 400;
}

.cm-tag-new,
.cm-tag-added {
    background: #47AE83;
}

.cm-tag-changed {
    background: #4569C4;
}

.cm-tag-fixed {
    background: #C23D45;
}

.cm-tag-removed {
    background: #3555A7;
}

.cm-tag-security {
    background: #EC8741;
}

.cm-tag-meeting {
    background: #7B55CA;
}

.cm-tag-support {
    background: #CE5CBC;
}