node_modules/@angular/material/slide-toggle/_slide-toggle-theme.scss

@import '../core/style/private';
@import '../core/theming/palette';
@import '../core/theming/theming';
@import '../core/typography/typography-utils';

@mixin _mat-slide-toggle-checked($palette, $thumb-checked-hue) {
  &.mat-checked {
    .mat-slide-toggle-thumb {
      background-color: mat-color($palette, $thumb-checked-hue);
    }

    .mat-slide-toggle-bar {
      // Opacity is determined from the specs for the selection controls.
      // See: https://material.io/design/components/selection-controls.html#specs
      background-color: mat-color($palette, $thumb-checked-hue, 0.54);
    }

    .mat-ripple-element {
      // Set no opacity for the ripples because the ripple opacity will be adjusted dynamically
      // based on the type of interaction with the slide-toggle (e.g. for hover, focus)
      background-color: mat-color($palette, $thumb-checked-hue);
    }
  }
}

@mixin mat-slide-toggle-color($config-or-theme) {
  $config: mat-get-color-config($config-or-theme);
  $is-dark: map-get($config, is-dark);
  $primary: map-get($config, primary);
  $accent: map-get($config, accent);
  $warn: map-get($config, warn);
  $background: map-get($config, background);
  $foreground: map-get($config, foreground);

  // Color hues are based on the specs which briefly show the hues that are applied to a switch.
  // The 2018 specs no longer describe how dark switches should look like. Due to the lack of
  // information for dark themed switches, we partially keep the old behavior that is based on
  // the previous specifications. For the checked color we always use the `default` hue because
  // that follows MDC and also makes it easier for people to create a custom theme without needing
  // to specify each hue individually.
  $thumb-unchecked-hue: if($is-dark, 400, 50);
  $thumb-checked-hue: default;

  $bar-unchecked-color: mat-color($foreground, disabled);
  $ripple-unchecked-color: mat-color($foreground, base);

  .mat-slide-toggle {
    @include _mat-slide-toggle-checked($accent, $thumb-checked-hue);

    &.mat-primary {
      @include _mat-slide-toggle-checked($primary, $thumb-checked-hue);
    }

    &.mat-warn {
      @include _mat-slide-toggle-checked($warn, $thumb-checked-hue);
    }

    &:not(.mat-checked) .mat-ripple-element {
      // Set no opacity for the ripples because the ripple opacity will be adjusted dynamically
      // based on the type of interaction with the slide-toggle (e.g. for hover, focus)
      background-color: $ripple-unchecked-color;
    }
  }

  .mat-slide-toggle-thumb {
    @include mat-private-theme-elevation(1, $config);
    background-color: mat-color($mat-grey, $thumb-unchecked-hue);
  }

  .mat-slide-toggle-bar {
    background-color: $bar-unchecked-color;
  }
}

@mixin mat-slide-toggle-typography($config-or-theme) {
  $config: mat-get-typography-config($config-or-theme);
  .mat-slide-toggle-content {
    font-family: mat-font-family($config);
  }
}

@mixin _mat-slide-toggle-density($config-or-theme) {}

@mixin mat-slide-toggle-theme($theme-or-color-config) {
  $theme: mat-private-legacy-get-theme($theme-or-color-config);
  @include mat-private-check-duplicate-theme-styles($theme, 'mat-slide-toggle') {
    $color: mat-get-color-config($theme);
    $density: mat-get-density-config($theme);
    $typography: mat-get-typography-config($theme);

    @if $color != null {
      @include mat-slide-toggle-color($color);
    }
    @if $density != null {
      @include _mat-slide-toggle-density($density);
    }
    @if $typography != null {
      @include mat-slide-toggle-typography($typography);
    }
  }
}