gnome-shell/data/theme/gnome-shell-sass/widgets/_app-grid.scss

/* App Grid */

$app_icon_size: 96px;
$app_icon_padding: 24px;

// app icons
.icon-grid {
  -shell-grid-horizontal-item-size: $app_icon_size + $app_icon_padding * 2;
  -shell-grid-vertical-item-size: $app_icon_size + $app_icon_padding * 2;
  spacing: $base_spacing * 6;

  .overview-icon {
    icon-size: $app_icon_size;
    StIcon { margin-bottom: $base_margin; } // margin on icon so label isn't close
  }
}

//.app-display { spacing: 20px; }

/* App Icons */

$app_grid_fg_color: #fff;

// Outline for low res icons
.lowres-icon {
  icon-shadow: 0 1px 2px rgba(0,0,0,0.3);
}

// Dropshadow for large icons
.icon-dropshadow {
  icon-shadow: 0 1px 2px rgba(0,0,0,0.4);
}

// Icon tiles in the app grid
.app-well-app,
.app-folder {

  .overview-icon {
    @extend %icon_tile;
    color: $app_grid_fg_color !important;
  }

  &:selected {
    .overview-icon {
      background-color: transparentize($osd_bg_color,0.7);
      color: $app_grid_fg_color;
    }
  }

  &:hover,
  &:focus,
  &:selected {
    .overview-icon {
      background-color: transparentize($osd_fg_color,0.9);
      color: $osd_fg_color;
    }
  }

  &:focus {
    .overview-icon {
      background-color: transparentize($osd_fg_color,0.7  );
      // border-color: $selected_bg_color;
      color: $app_grid_fg_color;
    }
  }

  &:drop {
    .overview-icon {
      background-color: transparentize($selected_bg_color,.15);
    }
  }

  &:active,
  &:checked {
    .overview-icon {
      background-color: transparentize(darken($osd_bg_color,10%), 0.5);
    }
  }
}

/* App Folders */
.app-folder {
  .overview-icon {
    @extend %icon_tile;
  }
}

// expanded folder
.app-folder-popup {
  -arrow-border-radius: 8px;
  -arrow-background-color: transparentize(darken($osd_bg_color,10%), 0.5);
  -arrow-base: 24px;
  -arrow-rise: 11px;
}

.app-folder-popup-bin { padding: $base_padding - 1px; }

.app-folder-icon {
  padding: $base_padding;
  spacing-rows: $base_spacing;
  spacing-columns: $base_spacing;
}


// Running app indicator (also shown in dash)
.app-well-app-running-dot {
  height: 5px;
  width: 5px;
  border-radius:5px;
  background-color: $osd_fg_color;
  margin-bottom: 1px;
}

// Rename popup for app folders
.rename-folder-popup {
  .rename-folder-popup-item {
    spacing: $base_spacing;
    &:ltr, &:rtl { padding: 0 $base_padding * 2; }
  }
}

// right-click app menu
.app-menu,
.app-well-menu {
  max-width: 27.25em;
}

// App Grid pagination indicators
.page-indicator {
  padding: 15px 20px;

  .page-indicator-icon {
    width: 10px;
    height: 10px;
    border-radius: 10px; // the same as height&width
    background-color: white;
  }
}

// Some hacks I don't even know
.all-apps,
.frequent-apps > StBoxLayout {
  // horizontal padding to make sure scrollbars or dash don't overlap content
  padding: 0px 88px 10px 88px;
}

.app-well-app > .overview-icon.overview-icon-with-label {
  padding: 10px 8px 5px 8px;
  spacing: $base_spacing;
}

// Label when no frequent apps
.no-frequent-applications-label { @extend %status_text; }

// shutdown and other actions in the grid
.system-action-icon {
  background-color: rgba(0,0,0,0.8);
  color: #fff;
  border-radius: 99px;
  icon-size: $app_icon_size * 0.5;
}

/* Frequent | All toggle */

// container
.app-view-controls { 
  padding-bottom: 32px;
}

// buttons
.app-view-control { 
  padding: $base_padding $base_padding*5;
  margin: 0;
  background-color: transparentize($osd_bg_color, 0.5);
  border-width: 1px;
  color: darken($osd_fg_color, 25%);

  &:hover {
    background-color: transparentize($osd_bg_color, 0.5) !important;
    box-shadow:none !important;
    color: darken($osd_fg_color, 25%);
  }

  &:active {
    box-shadow: none;
    background-color: $selected_bg_color !important;
    &:hover {
      background-color: lighten($selected_bg_color, 11%) !important;
    }
  }

  &:checked {
    background-color: $selected_bg_color !important;
    color: $selected_fg_color;
    box-shadow: none;
    &:active { background-color: darken($selected_bg_color, 4%) !important; }
    &:hover { background-color: lighten($selected_bg_color, 7%) !important; }
  }

  &:first-child {
    border-right-width: 0 !important;
    border-radius: $base_border_radius 0 0 $base_border_radius;
  }

  &:last-child {
    border-radius: 0 $base_border_radius $base_border_radius 0;
  }
}