For this we will need to make some small changes to the 
post_macros template.
Instructions
Find the following code block in the 
post_macros template:
	
	
	
		HTML:
	
	
		    <article class="message {{ extension_value('extra_classes') }} js-post js-inlineModContainer {{ $post.isIgnored() ? 'is-ignored' : '' }} {{ $post.isUnread() ? ' is-unread' : '' }}"
        data-author="{{ $post.User.username ?: $post.username }}"
        data-content="post-{$post.post_id}"
        id="js-post-{$post.post_id}"
        {{ $includeMicrodata ? 'itemscope itemtype="https://schema.org/' . $thread.getReplyMicrodataType() . '" itemid="' . $post.getContentUrl(true) . '"' : '' }}>
	 
 
Change this code completely as follows:
	
	
	
		HTML:
	
	
		    <article class="message {{ extension_value('extra_classes') }} js-post js-inlineModContainer {{ $post.isIgnored() ? 'is-ignored' : '' }} {{ $post.isUnread() ? ' is-unread' : '' }}"
        data-author="{{ $post.User.username ?: $post.username }}"
        data-rank="{{ $post.User.is_admin ? 'admin' : 'user' }}"
        data-content="post-{$post.post_id}"
        id="js-post-{$post.post_id}"
        {{ $includeMicrodata ? 'itemscope itemtype="https://schema.org/' . $thread.getReplyMicrodataType() . '" itemid="' . $post.getContentUrl(true) . '"' : '' }}>
	 
 
In the same template, find the following code:
	
	
	
		HTML:
	
	
		            <xf:if is="$post.isUnread()">
                <li><span class="message-newIndicator">{{ phrase('new') }}</span></li>
            <xf:elseif is="$thread.isUnread() && $showThreadUnreadIndicator" />
                <li><span class="message-newIndicator" title="{{ phrase('new_replies')|for_attr }}">{{ phrase('new') }}</span></li>
            </xf:if>
	 
 
Change this code completely as follows:
	
	
	
		HTML:
	
	
		            <xf:if is="$post.isUnread()">
                <li><span class="message-newIndicator">{{ phrase('new') }}</span></li>
            <xf:elseif is="$thread.isUnread() && $showThreadUnreadIndicator" />
                <li><span class="message-newIndicator" title="{{ phrase('new_replies')|for_attr }}">{{ phrase('new') }}</span></li>
            </xf:if>
            <li>
                <xf:if is="$post.User.is_admin">
                    <xf:userbanners user="$post.User" />
                </xf:if>
            </li>
	 
 
And finally, paste this CSS code into the 
extra.less template:
	
	
	
		CSS:
	
	
		[data-rank='admin'] {
  border-color: red !important;
  box-shadow: 0px 0 8px hsla(0deg, 100%, 50%, 42%);
}
	 
 
Let me know if there are any problems.