feat(Typography): update details block to blue color

What does this MR do and why?

The HTML <details> block is something I use often in comments, MRs, and issues. However, this block does not look interactive, nor does it stand out amongst other text. I usually have to write something like "click here to see..." to make the block more noticeable and signal its interactivity. Example:

Click here to see inside the details block

hehe, there's nothing in here

This MR proposes giving the details block a blue color to solve these issues.

Before	After

How to set up and validate locally

1. Find somewhere you can write text in GitLab (issue body, MR body, comment, etc.)
2. Create a details block and a summary block. (instructions below)
3. Save or preview the text you've written, see that the details block is now blue

How to write a plain details block:

<details>

write some stuff inside

</details>

How to write a details block + summary:

<details><summary> Here is a summary </summary>

write some stuff inside

</details>