[libadwaita] (30 commits) Non-fast-forward update to branch wip/exalm/flat-switcher

[Alexander Mikhaylenko <alexm src gnome org>]

The branch 'wip/exalm/flat-switcher' was changed in a way that was not a fast-forward update.
NOTE: This may cause problems for people pulling from the branch. For more information,
please see:

 https://wiki.gnome.org/Git/Help/NonFastForward

Commits removed from the branch:

  045032b... stylesheet: Special case colors for all flat buttons in hea
  4a24f30... view-switcher: Use .flat buttons

Commits added to the branch:

  f403dfe... stylesheet: Remove GtkWindowControl margins (*)
  a461cba... stylesheet: fix solid-csd style (*)
  4b633f1... Update Finnish translation (*)
  8d66b98... Update Basque translation (*)
  c4b0ab2... stylesheet: Drop backdrop list styles (*)
  2b0b3b3... stylesheet: Drop searchbar backdrop style (*)
  4ae7778... stylesheet: Remove a redundant backdrop bg color (*)
  b6cfbdc... stylesheet: Remove treeview backdrop styles (*)
  35f780d... stylesheet: Remove redundant popover:backdrop style (*)
  eef0d3e... stylesheet: Remove a backdrop-specific rule for notebook (*)
  02f57b7... stylesheet: Use opacity for caps lock indicator instead of  (*)
  2c3d4e8... stylesheet: Drop status page backdrop style (*)
  de3cc93... stylesheet: Drop unused backdrop overshoot glow (*)
  1231a34... stylesheet: Drop scale backdrop specificity bumps (*)
  2699f13... stylesheet: Remove entry backdrop specificity bumps (*)
  63107ed... stylesheet: Drop backdrop state for selection mode checks (*)
  f05331d... stylesheet: Drop unused backdrop check styles (*)
  de3c297... stylesheet: Drop backdrop style for buttons (*)
  863b79c... stylesheet: Transparentize header bar contents for backdrop (*)
  e9457af... stylesheet: Remove separate header bar border color for bac (*)
  5a0d966... stylesheet: Drop public backdrop colors (*)
  9a987ca... stylesheet: Fix shadow transition in dark variant (*)
  a5b3b03... stylesheet: Fix window shadows (*)
  0e0f981... stylesheet: Inline headerbar_fill() (*)
  ccc62cf... stylesheet: Adjust devel header bar gradient (*)
  555af46... stylesheet: Use a flat gradient for backdrop header bar (*)
  07effd3... stylesheet: Remove redundant header bar rules (*)
  3b8fce9... stylesheet: Make the .devel cog less prominent for backdrop (*)
  8e72f2b... stylesheet: Special case colors for all flat buttons in hea
  13250d7... view-switcher: Use .flat buttons

(*) This commit already existed in another branch; no separate mail sent