https://css-tip.com/
CSS Tip: Learn CSS the easy way
The best place to keep up to date with the new CSS features. Daily CSS tips and tricks to become a better web developer.
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https://www.a11yproject.com/posts/never-remove-css-outlines/
Quick tip: Never remove CSS outlines - The A11Y Project
Removing CSS outlines without proper fallbacks can make it impossible to navigate your site with a keyboard.
the a11y projectquick tipneverremovecss