Grid: make font smaller

How to make font, that is leveraged in grid smaller ?

If you want set font size for the whole Grid, you can set style name for Grid

grid.setStyleName("my-grid");

and apply css rule in your theme mixin (usually in mytheme.scss):

.my-grid {
   font-size: 20px;
}

Alternatively you can use grid.setStyleGenerator(…) (or respectively for a Column) in order to have smaller font only in selected cells.