WordPress Sticky Posts
However if you “stick” a post, it will always display at the top of the list of blog posts, even if there are more recently published blog posts.
To “stick” a post, edit the blog post using the WordPress dashboard. In the “Publish” meta box (top right), click the edit link next to Visibility Public, then tick the “Stick this post to the front page” checkbox. (See screenshot to right).
Advanced: Styling Sticky Posts using Custom CSS
Sticky posts are displayed using a class of sticky.
This means that you can write Custom CSS rules to style sticky posts.
For example:
.sticky { background-color: #CCCCCC; }
would display all sticky posts with a grey background colour.

