How to add Custom Css within the Editor?

From what you wrote it seems you might need to look at CSS Specificity… Which in short means: the more specific the CSS selector is, it has more value and therefore it will be used instead of the weaker one. (You can learn more about it for example here.) Plugins usually use more complex and … Read more

How to make a function to play only on the home page?

I feel like I’m missing a lot of context from your question. If you are only asking how to execute a script on the homepage (and not on other pages), you can use the is_front_page() function. You can wrap your entire script in an if statement, like below: <?php if ( is_front_page() ) : ?> … Read more