add OpenType features section

fix drop hint for failed drop

fix font flickering when adding font, add drop hint

update dependencies

fix textarea cutoff

change sidebar margin

Update README.md

styles

Merge pull request #3 from grimmle/feature/color-picker

handle error for uploading invalid file types

Merge branch 'main' into feature/color-picker

clean up mui-overrides

Merge pull request #4 from grimmle/fix/presets

fix preset placeholder behaviour

Merge pull request #2 from grimmle/feature/dropzone