我添加了自定义主题文件，我想减少整个网站的字体大小。我不知道如何通过自定义主题更改字体大小，因为没有适当的文档。
@import '~@angular/material/theming';
// Plus imports for other components in your app.
// Include the common styles for Angular Material. We include this here so that you only
// have to load a single css file for Angular Material in your app.
// Be sure that you only ever include this mixin once!
@include mat-core();
// Define the palettes for your theme using the Material Design palettes available in palette.scss
// (imported above). For each palette, you can optionally specify a default, lighter, and darker
// hue.
$candy-app-primary: mat-palette($mat-indigo);
$candy-app-accent: mat-palette($mat-pink, A200, A100, A400);
// The warn palette is optional (defaults to red).
$candy-app-warn: mat-palette($mat-red);
// Create the theme object (a Sass map containing all of the palettes).
$candy-app-theme: mat-light-theme($candy-app-primary, $candy-app-accent, $candy-app-warn);
// Include theme styles for core and each component used in your app.
// Alternatively, you can import and @include the theme mixins for each component
// that you are using.
@include angular-material-theme($candy-app-theme);