CSS class starting with number is not getting applied

Question

I\'m trying to create a webpage that contains images. However, I want all the images to be the same size and in the same format. I have the following CSS class which applies

Answer 1

CSS class names should not begin with a number (unless you're willing to do what @torazaburo's answer describes). So perhaps change that, i.e. the class name from "200-200" to "s200-200".

.200 {
  color: red;
}
.s200 {
  color: red;
}

I'm not red :(
I am red :)