How and through which extension can I create rules with adding styles to certain page elements in my browser?

Question

Google Chrome

For example, on a certain site there are divs with the class class = "blablablablock"
I need to check the contents of the div, and if inside the code of this div and everything that is nested in it, for example, "Peter Sidorov" is found, then the style attribute must be added to such a block with the entire div filled with red.
And also add my html code inside this div, which will contain my comment, which Peter Sidorov did not please me.

Of course, I do not expect that the html code will be saved on the server - I need these changes to occur only in my browser every time I visit that particular site.

How to implement this with what? In ad blockers, such rules are possible or what browser extension can be achieved for whom?

Answer 1

If anyone is interested, I'll answer my own question - the Tampermonkey extension and the like allow you to run custom Java scripts on certain pages. So you can do whatever you want with the html code.

Answer 2

there are 2-3 norms of the styler
this
https://chrome.google.com/webstore/detail/stylebot...
and look next to it
with more complicated comments, but there are also, most likely separate extensions
on stackoverflow it is convenient to highlight the dates as you say, right away it's clear how old the advice is