Spreadsheet border design

[juliusknorr]

Describe the Bug

Comparing spreadsheets with other solutions i noticed some small changes that could improve the overall look:

• The border size of columns seem to be 2px while all other solutions as well as Libreoffice on the desktop uses 1px

Collabora Online	Libreoffice Desktop	Microsoft Excel

• The border color seems to be not consistent, i though I reported this already but cannot find the issue (maybe it was just during a call)
  • Most visible in dark mode, but also the case in light mode. Every nth row is slightly changed in color

• The focus outline seems to have a slight blur, compared to other solutions where it is full color with increased size

Collabora Online	Libreoffice Desktop

cc @pedropintosilva @jancborchardt

[jancborchardt]

Agree with everything except the cell highlight color for LibreOffice Desktop is probably too light for accessibility, should probably be our color-primary-element?

[timur-g]

If this was tested in Firefox, then there is a bug there from version 115, menitoned also in #7316. Bisected and reported.

[juliusknorr]

You're right, sorry I somehow missed to test this in other browsers. Hoping for a quick upstream fix 🤞 Let me close this then as a duplicate of #7316