Fix DownloadSpine button hover showing the blue Arc

[Al12rs]

fix #887
Hover arc color style was applied for all cases, not just the .Progress class.
This moves the style to .Progress:pointerover

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (ca167e8) 0.00% compared to head (b0749cb) 58.32%.
Report is 4 commits behind head on main.

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Additional details and impacted files

@@            Coverage Diff            @@
##           main     #900       +/-   ##
=========================================
+ Coverage      0   58.32%   +58.32%     
=========================================
  Files         0      680      +680     
  Lines         0    22469    +22469     
  Branches      0     1940     +1940     
=========================================
+ Hits          0    13105    +13105     
- Misses        0     8999     +8999     
- Partials      0      365      +365     

Flag	Coverage Δ
Linux	58.28% <ø> (?)
clean_environment_tests	58.28% <ø> (?)

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see 680 files with indirect coverage changes