[sksasi]

Is it still ok to use px unit?

[shortcake27]

I use relative units (ems/rems) for font sizes and absolute units (px etc) for everything else such as margins/paddings/borders. I also set the html font size to 62.5% which makes the math easy (1rem = 10px).

This ensures that if a user adjusts their browsers font size for accessibility purposes or uses dynamic type, only the text will scale. You don’t want margins/paddings to scale with font size (at least not linearly) otherwise the layout gets cramped/unusable very quickly.

As others have mentioned CSS pixels have nothing to do with hardware pixels. So there are no issues with the differences in screen densities between devices.

[zamadatix]

px in CSS/web is just shorthand for 1/96th of an inch, regardless how many actual pixels that ends up being. This means it's functionally the same as any other absolute value of measurement on the web, since they are all based in some mapping to physical size as well.

[innocenat]

That's only true on (most) mobile devices. px is still 1 pixel on Desktop with 100% system UI zoom (e.g. non-hidpi monitors).

[system2]

I stick to percent personally. Easier to adjust if I am working on someone else's messed up css. rem/em depends on global values but many sites override these with different classes and manually entered pixel values. I find % to be safer than em/rem.

[dbbk]

I still use it, I have yet to find any actual downside to it.