I decided to fill out this task, as it is planned to resize the content area: T246420: Limit content width, and refine alignment & styling of relevant elements. And in this case, changing the font will even more affect the display of content in the future.
Currently font size in Vector skin ~= 14px. And it seems to me that it needs to be increased to at least 16 px (common practices and our style guide indicates the same size).