CSS - I would like to understand and learn

[Giamma]

I would like to learn how to write a CSS class without constantly asking for your help, as long as this does not mean revealing your professional "secrets" acquired in your professional activity.

Example:
I searched in the source code ...

of a dashboard information about the various components, but I can't find what I need, but Is it the right thing to do?

Example:
A few days ago, an user asked how to make the background of a group transparent, and @hotNipi replied:

.bg-group-background {
    background-color:transparent !important;
}

Where this information (.bg-group-background) can be found?
and again, I would like to be able to change the background color and size of the text of the list of dashboard...

Where this information can be found to create a class?
Let's start from here, if it's possibile ....

Thank you in advance for the help and patience.

[hotNipi]

First you do inspect the element of the interest

If it is selected/highlighted then you can see full cascade of the CSS which alters that element.

Then you can play with applied CSS rules to see what changes if you alter the CSS rules. You can turn on an off current rules and you can add your rules to some classes right inside the styles tab.

Those changes are temporary. If you find what you want that way, you can write your own classes to apply or override current rules.

From this point everything about the CSS gets complicated but adding and removing classes or rules is as easy as you already know.

[jbudd]

I believe the styling of the left hand sidebar is defined in the theme (?), so best not to try and change this with custom CSS.

[Giamma]

After a bit of test ....

Thank you .....