Alan Fuller

The new generation og WordPress themes are known as Block Themes, sometime referred to as Full Site Editing (FSE) or Gurenberg Themes.
These themes disable the older customizer, on the presumption that all styling can be done via the editor.
Unfortunately this is not so, and some styles still need custom CSS if you want to perfect your designs.
There are several plugins that allow you to add additional CSS however there is no need to add another plugin as the ability is still within Core WordPress, in the form of the customizer.
All it needs is it to be switched back on – no bloat- just a switch and you can then access the customizer and add additional CSS.
This is a really lightweight plugin that adds back the customizer when hidden by block themes.
The customizer is useful for block themes mainly because of Additional CSS.
Whilst it is still available for block themes, it is hidden. This plugin simply brings back the links.

Add Customizer Back For Block Themes

Nice, simple, and does exactly what it says. 

It's getting the job done.

Simply adds back the hidden customizer for Block Themes such as Twenty Twenty Two and Twenty Twenty Three

dessky

Dessky Custom CSS is the lightweight plugin that allows you to add custom CSS that overrides Plugins and Theme’s default styles. This plugin is built to allow admins to add their own CSS to their WordPress website without editing theme or plugin files. Plugin is specially designed not to drain any resources from your website and to be as simple as possible.
This plugin was developed by <a href="https://dessky.com/" rel="nofollow ugc">Dessky Team</a>.
Dessky Team does not provide support for the Dessky Custom CSS on the WordPress.org forums. In order to get support or make a suggestion from a Dessky Team you will have to Join Our Open Community and <a href="https://discuss.dessky.org/t/dessky-custom-css" rel="nofollow ugc">Start a Discussion</a>.
<a href="https://discuss.dessky.org/t/dessky-custom-css" rel="nofollow ugc">DISCUSS WITH THE DESSKY TEAM</a>
<a href="https://discuss.dessky.org/t/dessky-custom-css" rel="nofollow ugc">JOIN OUR OPEN COMMUNITY</a>: The purpose of this open community is to have a collective place where the community can help each other, and we can get some feedback to improve Dessky Custom CSS as well. Joining the community is also a great way to connect with like-minded people and share your experience.
You can also <a href="https://dessky.me/" rel="nofollow ugc">GET THE PREMIUM SUPPORT</a>
<a href="https://dessky.org/" rel="nofollow ugc">User Documentation</a>: Although Dessky Custom CSS is already easy to set up, we’ve put together tutorials, guides, and some knowledge bases to help you set up and get started with it.
I have further questions, how do I contact you?
Please fill up the <a href="https://dessky.com/contact/" rel="nofollow ugc">contact form</a> and we would be more than happy to assist.
<h4>Features</h4>
<ul>
<li>Lightweight and without any impact on site performance</li>
<li>Simple interface built on WordPress UI</li>
<li>Useful Code Syntax Highlighter</li>
<li>No configuration needed</li>
<li>No complicated database queries</li>
<li>Allows Administrator access on Multisite</li>
</ul>
<h4>Credits</h4>
Dessky Custom CSS is based on the ‘Simple Custom CSS’ plugin developed by <a href="https://profiles.wordpress.org/johnregan3/" rel="nofollow ugc">John Regan</a> and <a href="https://profiles.wordpress.org/dvankooten/" rel="nofollow ugc">Danny van Kooten</a>.
<a href="https://codemirror.net/" rel="nofollow ugc">CodeMirror</a> is an open-source project shared under the <a href="https://codemirror.net/LICENSE" rel="nofollow ugc">MIT license</a>.

Dessky Custom CSS

Lightweight plugin for adding Custom CSS to your WordPress site.

Add Customizer Back For Block Themes vs Dessky Custom CSS