Not anymore, as most px units now is based on a reference px, a size determined based on screen density and viewing distance. That's why something rendered at 6

Not anymore, as most px units now is based on a reference px, a size determined based on screen density and viewing distance. That's why something rendered at 600px on an iphone takes almost all the width, even though the screen has more than double that in pixels. And when zooming, the reference px is zoomed. So the old reason for not using px and instead use rem doesn't apply. https://developer.mozilla.org/en-US/docs/Glossary/CSS_pixel https://developer.mozilla.org/en-US/docs/Glossary/CSS_pixel