When I edit css with Custom CSS/JS where do I add styles?

Question

css

For some reason, changes made to the css of a theme or a child theme were not displayed on the product (product) page, the problem was solved by editing css through the top panel - "Customize" / Custom CSS / JS
In general, css was applied and earned, but I don’t understand where they are physically saved .

Answer 1

Most likely in the database. And that's bad. Then they are taken from there and inserted into the header inline.
And if you have a lot of such styles - it's very bad. This garbage should not be stored in the database. The options table bloats and the site starts working a little slower.
Inline styles take precedence over normal css files.
In order for styles to work out in a child theme - you must understand - they must be lower in the code (load later), because if they "weigh" (specificity) the same - then they should go later than the parent css. If they go earlier, then they need to make an "overweight" - for example, by adding :root or body before the class. More or less like this: :root .need-class {margin:2px;}