blogger CSS disappeared or can't find

Sometimes in blogger.com, when you try to edit CSS (Theme > Customize > Advanced > Add CSS), you find it missing!

This is usually a result of changes made to your Theme's HTML, such as adding a CSS file or a script.

However, you'll notice that nothing has changed on your site - so clearly your custom CSS is still there.

Whilst I'm not exactly sure what the cause is, my guess it that this is not a bug, but rather a symptom of design. Without being able to see code base of blogger, my guess is when you first select your theme, there an initialisation script that runs which instantiates a reference point for "add CSS" component. However, when you make custom changes to the HTML, this reference point is lost either due to it not being updated, or possibly - it is overwritten to be empty. 

How to fix

When you 'add CSS', blogger just appends it onto the theme's HTML page within the  <b:skin> tag.

So the fix is to grab it back!

(a bit hacky i know but it works)

STEP 1: navigate to Theme > ... > Edit HTML

STEP 2: Click into the code editor, then hit CTRL-F (or CMD-F) and search for </b:skin> 

STEP 3: Select all your custom CSS between }} and </b:skin>, then CUT it (CTRL/CMD-X).

Finaly return to add CSS and paste it back in.

Hopefully this won't happen too often as you won't be needing to edit HTML too much.

It's also useful to keep a backup copy of your CSS in a style sheet locally.

Hope that helps!