gecko-dev/browser/components/newtab/content-src/styles/_theme.scss

@function textbox-shadow($color) {
  @return 0 0 0 1px $color, 0 0 0 $textbox-shadow-size rgba($color, 0.3);
}

@mixin textbox-focus($color) {
  --newtab-textbox-focus-color: #{$color};
  --newtab-textbox-focus-boxshadow: #{textbox-shadow($color)};
}

// scss variables related to the theme.
$border-primary: 1px solid var(--newtab-border-primary-color);
$border-secondary: 1px solid var(--newtab-border-secondary-color);
$inner-box-shadow: 0 0 0 1px var(--newtab-inner-box-shadow-color);
$input-border: 1px solid var(--newtab-textbox-border);
$input-border-active: 1px solid var(--newtab-textbox-focus-color);
$input-error-border: 1px solid $red-60;
$input-error-boxshadow: textbox-shadow($red-60);
$shadow-primary: 0 0 0 5px var(--newtab-card-active-outline-color);
$shadow-secondary: 0 1px 4px 0 $grey-90-20;

// Default theme
body {
  // General styles
  --newtab-background-color: #{$grey-10};
  --newtab-border-primary-color: #{$grey-40};
  --newtab-border-secondary-color: #{$grey-30};
  --newtab-element-active-color: #{$grey-30-60};
  --newtab-element-hover-color: #{$grey-20};
  --newtab-icon-primary-color: #{$grey-90-80};
  --newtab-icon-secondary-color: #{$grey-90-60};
  --newtab-icon-tertiary-color: #{$grey-30};
  --newtab-inner-box-shadow-color: #{$black-10};
  --newtab-link-primary-color: #{$blue-60};
  --newtab-link-secondary-color: #{$teal-70};
  --newtab-text-conditional-color: #{$grey-60};
  --newtab-text-primary-color: #{$grey-90};
  --newtab-text-secondary-color: #{$grey-50};
  --newtab-textbox-background-color: #{$white};
  --newtab-textbox-border: #{$grey-90-20};
  @include textbox-focus($blue-60); // sass-lint:disable-line mixins-before-declarations

  // Buttons
  --newtab-button-primary-color: #{$blue-60};
  --newtab-button-secondary-color: inherit;
  // Feed buttons
  --newtab-feed-button-background: #{$grey-20};
  --newtab-feed-button-text: #{$grey-90};
  --newtab-feed-button-background-faded: #{$grey-20-60};
  --newtab-feed-button-text-faded: #{$grey-90-00};
  --newtab-feed-button-spinner: #{$grey-50};


  // Context menu
  --newtab-contextmenu-background-color: #{$grey-10};
  --newtab-contextmenu-button-color: #{$white};

  // Modal + overlay
  --newtab-modal-color: #{$white};
  --newtab-overlay-color: #{$grey-20-80};

  // Sections
  --newtab-section-header-text-color: #{$grey-50};
  --newtab-section-navigation-text-color: #{$grey-50};
  --newtab-section-active-contextmenu-color: #{$grey-90};

  // Search
  --newtab-search-border-color: transparent;
  --newtab-search-dropdown-color: #{$white};
  --newtab-search-dropdown-header-color: #{$grey-10};
  --newtab-search-header-background-color: #{$grey-10-95};
  --newtab-search-icon-color: #{$grey-90-40};
  --newtab-search-wordmark-color: #{$firefox-wordmark-default-color};

  // Top Sites
  --newtab-topsites-background-color: #{$white};
  --newtab-topsites-icon-shadow: inset #{$inner-box-shadow};
  --newtab-topsites-label-color: inherit;

  // Cards
  --newtab-card-active-outline-color: #{$grey-30};
  --newtab-card-background-color: #{$white};
  --newtab-card-hairline-color: #{$black-10};
  --newtab-card-placeholder-color: #{$grey-30};
  --newtab-card-shadow: 0 1px 4px 0 #{$grey-90-10};

  // Snippets
  --newtab-snippets-background-color: #{$white};
  --newtab-snippets-hairline-color: transparent;

  // Trailhead
  --trailhead-header-text-color: #{$trailhead-purple};
  --trailhead-cards-background-color: #{$grey-20};
  --trailhead-card-button-background-color: #{$grey-90-10};
  --trailhead-card-button-background-hover-color: #{$grey-90-20};
  --trailhead-card-button-background-active-color: #{$grey-90-30};

  &[lwt-newtab-brighttext] {
    // General styles
    --newtab-background-color: #{$grey-80};
    --newtab-border-primary-color: #{$grey-10-80};
    --newtab-border-secondary-color: #{$grey-10-10};
    --newtab-button-primary-color: #{$blue-60};
    --newtab-button-secondary-color: #{$grey-70};
    --newtab-element-active-color: #{$grey-10-20};
    --newtab-element-hover-color: #{$grey-10-10};
    --newtab-icon-primary-color: #{$grey-10-80};
    --newtab-icon-secondary-color: #{$grey-10-40};
    --newtab-icon-tertiary-color: #{$grey-10-40};
    --newtab-inner-box-shadow-color: #{$grey-10-20};
    --newtab-link-primary-color: #{$blue-40};
    --newtab-link-secondary-color: #{$pocket-teal};
    --newtab-text-conditional-color: #{$grey-10};
    --newtab-text-primary-color: #{$grey-10};
    --newtab-text-secondary-color: #{$grey-10-80};
    --newtab-textbox-background-color: #{$grey-70};
    --newtab-textbox-border: #{$grey-10-20};
    @include textbox-focus($blue-40); // sass-lint:disable-line mixins-before-declarations

    // Feed buttons
    --newtab-feed-button-background: #{$grey-70};
    --newtab-feed-button-text: #{$grey-10};
    --newtab-feed-button-background-faded: #{$grey-70-60};
    --newtab-feed-button-text-faded: #{$grey-10-00};
    --newtab-feed-button-spinner: #{$grey-30};

    // Context menu
    --newtab-contextmenu-background-color: #{$grey-60};
    --newtab-contextmenu-button-color: #{$grey-80};

    // Modal + overlay
    --newtab-modal-color: #{$grey-80};
    --newtab-overlay-color: #{$grey-90-80};

    // Sections
    --newtab-section-header-text-color: #{$grey-10-80};
    --newtab-section-navigation-text-color: #{$grey-10-80};
    --newtab-section-active-contextmenu-color: #{$white};

    // Search
    --newtab-search-border-color: #{$grey-10-20};
    --newtab-search-dropdown-color: #{$grey-70};
    --newtab-search-dropdown-header-color: #{$grey-60};
    --newtab-search-header-background-color: #{$grey-80-95};
    --newtab-search-icon-color: #{$grey-10-60};
    --newtab-search-wordmark-color: #{$firefox-wordmark-darktheme-color};

    // Top Sites
    --newtab-topsites-background-color: #{$grey-70};
    --newtab-topsites-icon-shadow: none;
    --newtab-topsites-label-color: #{$grey-10-80};

    // Cards
    --newtab-card-active-outline-color: #{$grey-60};
    --newtab-card-background-color: #{$grey-70};
    --newtab-card-hairline-color: #{$grey-10-10};
    --newtab-card-placeholder-color: #{$grey-60};
    --newtab-card-shadow: 0 1px 8px 0 #{$grey-90-20};

    // Snippets
    --newtab-snippets-background-color: #{$grey-70};
    --newtab-snippets-hairline-color: #{$white-10};

    // Trailhead
    --trailhead-header-text-color: #{$white-60};
    --trailhead-cards-background-color: #{$grey-90-10};
    --trailhead-card-button-background-color: #{$grey-90-30};
    --trailhead-card-button-background-hover-color: #{$grey-90-50};
    --trailhead-card-button-background-active-color: #{$grey-90-70};
  }
}