To create debugger for CSS, there are 2 great ways to do:
Outline
Instead of using border (which taking space and can cause more overflow issues), use outline. It draws a line around every element without affecting the actual layout space.
* {
outline: 1px solid red;
}Background color
Outlines can sometimes get messy if you have a lot of nested elements. A great alternative is applying a semi-transparent background color.
* {
background: rgb(255 0 0 / 10%);
}