gtk.css

@define-color window_bg_color #fafafa;
@define-color window_fg_color #000000;
@define-color view_bg_color #ffffff;
@define-color view_fg_color @window_fg_color;
@define-color accent_bg_color #0d47a1;
@define-color accent_fg_color #ffffff;
@define-color accent_color @accent_bg_color;
@define-color headerbar_bg_color #ebebeb;
@define-color headerbar_backdrop_color @window_bg_color;
@define-color headerbar_fg_color @window_fg_color;
@define-color popover_bg_color @view_bg_color;
@define-color popover_fg_color @view_fg_color;
@define-color card_bg_color @view_bg_color;
@define-color card_fg_color @view_fg_color;
.dim-label {
  opacity: 0.9;
}

windowcontrols > button > image:not(:backdrop),
button.titlebutton:not(:backdrop) {
  color: @window_fg_color;
  box-shadow: inset 0 0 0 1px alpha(currentColor,0.15);
}
windowcontrols > button > image:backdrop,
button.titlebutton:backdrop {
  background-color: transparent;
}
windowcontrols > button > image:backdrop:hover,
button.titlebutton:backdrop:hover {
  box-shadow: inset 0 0 0 1px alpha(currentColor,0.15);
}

switch {
  background-color: alpha(currentColor,0.3);
}
switch:hover:not(:checked) {
  background-color: alpha(currentColor,0.4);
}
switch:checked {
  color: @window_fg_color;
  background-color: @accent_bg_color;
}
switch:checked:hover {
  background-image: image(alpha(currentColor,0.1));
}
switch:checked:hover:active {
  background-image: image(rgba(0, 0, 0, 0.2));
}

scale trough:not(:backdrop),
progressbar trough:not(:backdrop) {
  background-color: alpha(currentColor,0.3);
  color: @window_fg_color;
}

scrollbar slider {
  color: @window_fg_color;
  background-color: alpha(currentColor,0.6);
}
scrollbar slider:hover {
  background-color: alpha(currentColor,0.8);
}
scrollbar slider:active {
  background-color: @accent_bg_color;
}
scrollbar.overlay-indicator {
  opacity: 1;
}

notebook > header tab:checked.reorderable-page,
tabbar tab:checked {
  background-color: @view_bg_color;
  box-shadow: inset 0 -3px @accent_bg_color;
}
notebook > header tab:checked.reorderable-page:backdrop,
tabbar tab:checked:backdrop {
  background-color: @window_bg_color;
  box-shadow: inset 0 -3px shade(@window_bg_color,0.9);
}

.nautilus-list-view .view:selected, .nautilus-list-view .view:selected:hover {
  background-color: @accent_bg_color;
  color: @accent_fg_color;
}