Update style.css

[gabrieldesousah]

Gitlab was broken the text "Start Timer" on collapsed right sidebar

Please remember the Contributing Guidelines :heart:

:star2: What does this PR do?

Fix the position of "Start Timer" button on gitlab with the right sidebar collapsed

:bug: Recommendations for testing

All changes should be tested across Chrome and Firefox.

:memo: Links to relevant issues or information

[glensc]

@gabrieldesousah include a screenshot for "after" as well?