Use a new CSS file to override current website's CSS

Question

My website has currently 3 CSS files that are automatically included as a part of the website and I do not have access to the source i.e. index.html

Answer 1

In your new CSS file, add !important to the block of code, for instance:

if you have this on css1.css:

 h2{
 color:#000;
 }

In css4.css put the same element, but with !important, as follows;

 h2{
 color:#ccc !important;
 }

Therefor, !important will force that this style will be by all means the style set for the element to which it's applied.