Drag a letter to move it. The red dot is the origin — sliding it changes the space before the letter without moving the letter itself. The blue dot sets the advance width, the yellow dot stretches width, and the green dot stretches height. Drag the base tag to raise or lower just that letter, or the cap / x tags to set the whole font's cap height and x-height. Arrow keys nudge by 5 units, Shift+arrows by 25, [ ] width, and { } height.