👉 CSS Demystified: https://thecascade.dev/courses/css-demystified/

🔗 Links
✅ The Bramus article on viewport units that I mentioned: https://www.bram.us/2026/01/15/100vw-horizontal-overflow-no-more/
✅ How I decide when to use Flexbox or Grid: https://youtu.be/3elGSZSWTbM

✉ Keep up to date with everything I'm up to  https://www.kevinpowell.co/newsletter
💬 Come hang out with other devs in my Discord Community https://discord.gg/nTYCvrK
⭐ Are you a beginner? HTML & CSS for absolute beginners is for you: https://learn.kevinpowell.co
🎓 Start writing CSS with confidence with CSS Demystified: [https://cssdemystified.com](https://cssdemystified.com/)
🚀 Already mastered CSS? Check out my advanced course, Beyond CSS: https://www.beyondcss.dev/

⌚ Timestamps
00:00 - Useless declarations
02:00 - work with the browser, not against it
05:05 - staying organized and refactoring
08:40 - don’t remove outlines
11:25 - using the right tool for the right job

#css

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If you'd like a behind the scenes and previews of what's coming up on my YouTube channel:

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And whatever you do, don't forget to keep on making your corner of the internet just a little bit more awesome!

Kevin Powell

Five common CSS mistakes that even experienced developers make: (1) Useless declarations like unnecessary `width: 100%` that can cause overflow issues with margins or in flex/grid contexts. (2) Being overly prescriptive with fixed heights instead of using `min-height` or `max-width` to work with browser defaults. (3) Poor code organization and failing to refactor duplicated styles. (4) Removing focus outlines with `outline: none` instead of using `:focus-visible`, which breaks keyboard navigation accessibility. (5) Overusing flexbox or grid when the other layout tool would be more appropriate, a pattern increasingly seen in AI-generated CSS.

5 CSS fouls that I see way too often