[FR] Optional smaller line-height (name it "Compact text area")

### Description

Default line-height isn't optimal for me on older laptop. Font size and line-height are too large (even if font-size "Small" was selected).

Set this optional line-height 1 em (default seems to be 1.5?). Just tiny CSS hack.

### Impact

More compact text area, more text would be visible.

### Additional Context

Also please implement UI zooming ASAP...