
Getting Started
Widget Styling
Other Frontend Libraries
Custom Styling Guide
This guide provides the complete default CSS used by the FastComments commenting widget (v2) and some instructions for overriding the styles.
Understanding the default CSS allows you to:
- Customize the appearance by overriding specific styles
- Troubleshoot styling issues by seeing which classes and selectors are available
- Build custom themes that work with the widget's structure
- Use with AI assistants to generate custom CSS modifications.
How to Override Styles
Overriding styles varies based on the widget. For the comment widget, you have to use the customCSS config parameter to
pass the CSS into the iframe, or specify the CSS in the Customization page in the admin dashboard which will serve the CSS
from our CDN.
How to Customize Styles 
How to Customize Comment Widget Styles
You can customize the comment widget styling in two ways:
Option 1: Via customCSS Parameter
Pass your custom CSS as a string to the customCSS parameter when initializing the widget:
window.FastCommentsUI(document.getElementById('fastcomments-widget'), {
tenantId: 'your-tenant-id',
customCSS: `
.fast-comments .comment {
background-color: #f0f0f0 !important;
border-radius: 8px !important;
}
`
});
Option 2: Via Admin Dashboard
- Go to the Widget Customization page in your admin dashboard
- Scroll to the "Custom CSS" section under "Advanced"
- Enter your custom CSS
- Click "Save"
Your custom CSS will be applied to all comment widgets on your site.
Tips
- Use
!importantto override default styles if needed - Target specific selectors to avoid affecting other parts of your site
- Test your CSS in different browsers for compatibility
- The widget uses standard CSS - no special preprocessors required
Comment Widget Styling Reference (v2, latest) 

Recent Comments Widget Styling 
The Recent Comments widget displays a list of the most recent comments across your site or for a specific page.
This widget includes minimal default styling and is designed to be easily customized with your own CSS.
Widget Structure
The widget renders with the following HTML structure:
<div class="fastcomments-recent-comments">
<div class="comment">
<div class="user-details">
<img src="..." alt="Avatar" class="avatar" />
<span class="user-name">Username</span>
<span class="reply-date-time">2 hours ago</span>
</div>
<div class="comment-text">Comment content...</div>
<div class="link-wrapper">
<a class="link" href="...">Page Title</a>
</div>
</div>
<!-- More comments... -->
</div>
Recent Comments Default CSS Reference
The widget includes the following minimal default styling:

Customization Examples
Change Avatar Size
.fastcomments-recent-comments .comment .user-details img {
width: 32px !important;
height: 32px !important;
border-radius: 50%;
}
Change Comment Text Truncation
The default styling uses CSS tricks to truncate long comments with "...". To disable:
.fastcomments-recent-comments .comment .comment-text:before,
.fastcomments-recent-comments .comment .comment-text:after {
display: none !important;
}
Add Border to Comments
.fastcomments-recent-comments .comment {
border-bottom: 1px solid #eee !important;
padding-bottom: 10px !important;
}
Top Pages Widget Styling 
The Top Pages widget displays a list of your most commented pages.
This widget includes minimal default styling and is designed to be easily customized with your own CSS.
Widget Structure
The widget renders with the following HTML structure:
<div class="fastcomments-top-pages">
<div class="page">
<a class="title-link" href="...">Page Title (42)</a>
</div>
<!-- More pages... -->
</div>
Top Pages Default CSS Reference
The widget includes the following minimal default styling:

Customization Examples
Add Styling to Links
.fastcomments-top-pages .title-link {
color: #0066cc !important;
text-decoration: none !important;
font-size: 14px !important;
}
.fastcomments-top-pages .title-link:hover {
text-decoration: underline !important;
}
Add Borders Between Pages
.fastcomments-top-pages .page {
border-bottom: 1px solid #eee !important;
padding: 10px 0 !important;
}
.fastcomments-top-pages .page:last-child {
border-bottom: none !important;
}
Style the Comment Count
.fastcomments-top-pages .title-link {
display: flex !important;
justify-content: space-between !important;
}