my-component.tsx

import { Component } from '@stencil/core';

@Component({
  tag: 'my-component',
  styleUrl: 'my-component.css',
  shadow: true
})
export class MyComponent {
  render() {
    return <div class="overlay">
      <div class="modal-window">
        <div class="modal-window__content">
          <slot></slot>
        </div>
      </div>
    </div>;
  }
}