Improve SVG Icon Visibility in Dark Mode on GitHub Preview Pages

[Axeia]

On the following preview pages:

• Filled Icons
• Light Icons
• Regular Icons

The icons are very hard to see when the OS is set to dark mode, which in turn makes GitHub render in dark mode. Here is an example of the ‘filled’ icons under Windows 11 (in Google Chrome) with Windows’ color mode set to ‘Dark’:

All SVGs have a hardcoded color value of #212121. Setting this to a color with better contrast would make the pages much more accessible for dark mode users.

Alternatively, using currentColor as the fill value might automatically use the font color of the page, ensuring suitable contrast in all situations, although I have not tested this.