Is there a way to change height of rows from css?
By default grid works in mode where height of row fixed, you can switch to flexible row height mode by
grid.enableMultiline(true);
If you need to have fixed row height, just with another size, you can update it in dhtmlxGrid.css
div.gridbox table.row20px tr td{
height:Npx;
Please beware that in SmartRendering mode few additional steps required to have correct functionality with changed row height