node_modules/@angular/material/chips/_chips-theme.scss

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

$mat-chip-remove-font-size: 18px;

@mixin _mat-chip-element-color($foreground, $background) {
  background-color: $background;
  color: $foreground;

  .mat-chip-remove {
    color: $foreground;
    opacity: 0.4;
  }
}


// Applies the background color for a ripple element.
// If the color value provided is not a Sass color,
// we assume that we've been given a CSS variable.
// Since we can't perform alpha-blending on a CSS variable,
// we instead add the opacity directly to the ripple element.
@mixin _mat-chips-ripple-background($palette, $default-contrast, $opacity) {
  $background-color: mat-color($palette, $default-contrast, $opacity);
  background-color: $background-color;
  @if (type-of($background-color) != color) {
    opacity: $opacity;
  }
}

@mixin _mat-chip-theme-color($palette) {
  @include _mat-chip-element-color(mat-color($palette, default-contrast), mat-color($palette));

  .mat-ripple-element {
    @include _mat-chips-ripple-background($palette, default-contrast, 0.1);
  }
}

@mixin mat-chips-color($config-or-theme) {
  $config: mat-get-color-config($config-or-theme);
  $is-dark-theme: map-get($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);

  $unselected-background: mat-color($background, unselected-chip);
  $unselected-foreground: mat-color($foreground, text);

  .mat-chip.mat-standard-chip {
    @include _mat-chip-element-color($unselected-foreground, $unselected-background);

    &:not(.mat-chip-disabled) {
      &:active {
        @include mat-private-theme-elevation(3, $config);
      }

      .mat-chip-remove:hover {
        opacity: 0.54;
      }
    }

    &.mat-chip-disabled {
      opacity: 0.4;
    }

    &::after {
      background: map-get($foreground, base);
    }
  }

  .mat-chip.mat-standard-chip.mat-chip-selected {
    &.mat-primary {
      @include _mat-chip-theme-color($primary);
    }

    &.mat-warn {
      @include _mat-chip-theme-color($warn);
    }

    &.mat-accent {
      @include _mat-chip-theme-color($accent);
    }
  }
}

@mixin mat-chips-typography($config-or-theme) {
  $config: mat-get-typography-config($config-or-theme);
  .mat-chip {
    font-size: mat-font-size($config, body-2);
    font-weight: mat-font-weight($config, body-2);

    .mat-chip-trailing-icon.mat-icon,
    .mat-chip-remove.mat-icon {
      font-size: $mat-chip-remove-font-size;
    }
  }
}

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

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

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