How to change format of [code][/code] and [spoiler][/spoiler], etc.

I would like to know how to change the format of the spoiler boxes and the code boxes.
On the default phpbb2 format, the boxes are very small and can be unreadable, but on phpbb3 there is padding around the boxes, the font is bigger, and the color is different.

Shown here:

Spoiler:

Code:

hi

Another thing is that there is a border around the whole box.

How could I manage the format of those boxes?

Via css, what exactly do you want to change?

Sanket wrote:Via css, what exactly do you want to change?

I want to change the padding around the text, the color of the box, and make a border around it as well.
I know it seems like it alot, but I just want to make it just like the format on this site.

Take a look at this for code box
https://help.forumotion.com/script-code-problems-f43/code-box-help-t61299.htm#399282