codecov_colors_bookmarklet.js

javascript:(function(){
  const set_color = (cls, col) => document.querySelectorAll(cls).forEach(el => {
    el.parentNode.style.backgroundColor = col;
    el.parentNode.querySelectorAll('td').forEach(td => {td.style.backgroundColor = col});
  });
  set_color('.bg-ds-coverage-partial', '#ffa');
  set_color('.bg-ds-coverage-uncovered', '#fdd');
})();

Usage:

• Create a new bookmark
• copy the above js into the "link"
• call it some like "Codecov Colors" (or "Colours" if you come from a country that spells properly)
• click it when viewing code in codecov to apply easier to view colors

They could have easily implemented a color-blind settings that was fully client-side without much effort, but someone needs to think about that.

I've updated this script to work with the new horrid theme.