Specifically, most frontend developers have an abysmal knowledge of CSS, even though it& #39;s a crucial part of building fast, responsive, and smooth user interfaces.
I cannot count to number of times I& #39;ve seen offensively bad UI transitions because they were relying on expensive properties like `width` or `margin`, or all the terrible touch-based sliders performing poorly because they were not using CSS Snap Points, …
Or all the custom form elements being totally inaccessible because the devs didn& #39;t know how to override default styles, or all the jarring sticky navs not using native positioning, …
Or all the janky custom JS anchor scrolling because the devs didn& #39;t know about CSS scroll-behavior, or all the massive reflows and resize handlers because viewport units and CSS grid weren& #39;t used for layout, and a gazillion of other terrifying examples.
It matters a lot, because this lack of knowledge of CSS makes it impossible to build native-like user experiences on the web, even though the platform is very much capable to deliver these results nowadays.