Mary Rose Elbambo

BlockGlow adds a “BlockGlow — Custom CSS” panel to the inspector of every block. Use it to scope custom CSS to a single block instance. The plugin stores CSS in the uploads folder (under uploads/blockglow/) and enqueues the generated CSS file when rendering on the front end. If the uploads directory isn’t writable or file write fails, BlockGlow will fall back to outputting inline styles.
Key features:
<ul>
<li>Adds two block attributes to every block: <code>blockglowCustomCSS</code> and <code>blockglowId</code>.</li>
<li>Inspector panel with a CodeMirror-backed code editor (if WordPress provides it) or a fallback textarea supporting Tab and Shift+Tab outdent.</li>
<li>Live preview inside the block editor: custom CSS is scoped to the block in the editor so you can see the effect while editing.</li>
<li>CSS files are saved to <code>wp-content/uploads/blockglow/blockglow-<id>.css</code> and enqueued on the front end as a linked stylesheet; files are removed automatically when you clear the Custom CSS field.</li>
<li>Graceful fallback to inline styles when file writing isn’t possible.</li>
</ul>
How scoping works:
BlockGlow creates a unique <code>blockglowId</code> for each block instance and scopes your CSS with a wrapper selector like:
<pre><code>[data-blockglow-id="bg-xxxxxxx"] { /* your declarations */ }
</code></pre>
For convenience you can use <code>&</code> as the wrapper shorthand in the editor. Example:
<pre><code>& .my-class { color: red; }
</code></pre>
The plugin will replace <code>&</code> with the wrapper selector for both editor preview and front-end output.
<h3>Support</h3>
If you find issues or want improvements (for example: limiting who can edit per-block CSS, collecting styles into a single head include, or adding an admin UI to manage generated CSS files), open an issue in the repository or reply here and I will assist.

BlockGlow — Per-block Custom CSS

Adds a "Custom CSS" inspector panel to every Gutenberg block and saves per-block CSS files to uploads for front-end enqueuing.

SaifuMak

Add custom codes to your wordpress website. You can add custom PHP Functions, HTML, custom CSS, Javascript, Google Analytics, Search Console verification tags or other code snippets to your site.
Features
<ul>
<li>100% free wordpress plugin, no paid upgrades needed!</li>
<li>Add PHP Snippets, Custom CSS, Javascript, Google Analytics, Facebook Scripts, Meta Verification Codes, Search console verification and other codes to your wordpress website easily.</li>
<li>Generate Shortcodes for HTML Snippets and use it anywhere on the site!</li>
<li>Syntax highlighter enabled with Light and Dark Mode Editors</li>
<li>Classify snippets using tags</li>
<li>Add Notes to Snippets</li>
<li>Activate/Inactivate snippets with a single click</li>
<li>Auto-deactivate feature for PHP snippets that causes errors.</li>
<li>Add Custome Codes globally or on individual posts, pages, products and even on custom post types.</li>
<li>Option to select where to put snippets: before </head> or before </body> etc.</li>
<li>Import/Export Snippets to use on other sites.</li>
</ul>

Add Custom Codes – Insert Header, Footer, Custom PHP Snippets, CSS, Javascript

Plugin works faster. Contact support if any problem happens.

Works fast

A completely free plugin to add Custom PHP functions, HTML, CSS, Javascript, any other custom codes to your wordpress website.

BlockGlow — Per-block Custom CSS vs Add Custom Codes – Insert Header, Footer, Custom PHP Snippets, CSS, Javascript