I am writing an application in react and there was such a problem - the font-weight does not change only for the select tag (well, for its options, respectively, too). The pictures below show that for the text input the style 300 is applied, but for the select it does not. You can see from the top input that font-weight: 300 is loaded into the project. If you change to thicker ones, then everything works correctly. But thinner styles don't work.
The font is connected to the project in this way
<link href="https://fonts.googleapis.com/css?family=Raleway:300,500,700&display=swap" rel="stylesheet"/>
font-weight for the select is correct (300px), but it isn't shown