Angular Material removes previous styling after installation

Question

I made a Homepage for my company and i wanted to add a contact form with angular material. After i installed Angular Material all my h1 and h2 an p stylings are like removed or overwritten. When i remove the Angular Material code in the global styles.scss file the headlines and texts are back to normal but the material components are not styled.

Here are some screenshots:

This is without the material code in the styles.scss - this is how it should look

And this is how it looks with the code

and here is the code thats added to styles.scss:

// Custom Theming for Angular Material
// For more information: https://material.angular.io/guide/theming
@use '@angular/material' as mat;
// 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. Available color palettes: https://material.io/design/color/
$website-primary: mat.define-palette(mat.$indigo-palette);
$website-accent: mat.define-palette(mat.$pink-palette, A200, A100, A400);

// The warn palette is optional (defaults to red).
$website-warn: mat.define-palette(mat.$red-palette);

// Create the theme object. A theme consists of configurations for individual
// theming systems such as "color" or "typography".
$website-theme: mat.define-light-theme((
  color: (
    primary: $website-primary,
    accent: $website-accent,
    warn: $website-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 mat.all-component-themes($website-theme);