Cernocky

The Custom Post Styles plugin is an easy way to customize css of your posts individualy using CSS code. 
Plugin adds css editor box in your post editor.
See it in action: 
https://vimeo.com/179525212
Improve the user experience for your readers without having to change theme code.
<h4>Possible upcoming features</h4>
<ul>
<li>Better CSS editor</li>
<li>Custom webfonts</li>
<li>Supporting more post types</li>
<li>Custom styles for posts by categories, authors etc.</li>
<li>Visual editor</li>
</ul>

Custom Post Styles

Allows you to add custom css styles to posts.

shazdeh

Just like the way you can create custom page templates, this plugin enables you to build category archive templates by adding this bit to the top of your file:
<pre><code><?php
/**
 * Category Template: Grid
 */
?>
</code></pre>
and when you’re adding or editing categories, you can choose the desired template file.
This plugin is maintained solely for backward compatibility. Try the new <a href="https://wordpress.org/plugins/custom-taxonomy-templates/" rel="ugc">Custom Taxonomy Templates</a> instead, it supports all taxonomies and also uses the new term meta feature in WP 4.4.

Custom Category Templates

Define custom templates for category views.

Custom Post Styles vs Custom Category Templates