@wordpress/block-editor/build-style/default-editor-styles.css

Generic block editor.

/**
 * SCSS Variables.
 *
 * Please use variables from this sheet to ensure consistency across the UI.
 * Don't add to this sheet unless you're pretty sure the value will be reused in many places.
 * For example, don't add rules to this sheet that affect block visuals. It's purely for UI.
 */
/**
 * Colors
 */
/**
 * Fonts & basic variables.
 */
/**
 * Typography
 */
/**
 * Grid System.
 * https://make.wordpress.org/design/2019/10/31/proposal-a-consistent-spacing-system-for-wordpress/
 */
/**
 * Radius scale.
 */
/**
 * Elevation scale.
 */
/**
 * Dimensions.
 */
/**
 * Mobile specific styles
 */
/**
 * Editor styles.
 */
/**
 * Block & Editor UI.
 */
/**
 * Block paddings.
 */
/**
 * React Native specific.
 * These variables do not appear to be used anywhere else.
 */
/**
 * Default editor styles.
 *
 * These styles are shown if a theme does not register its own editor style,
 * a theme.json file, or has toggled off "Use theme styles" in preferences.
 */
body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen-Sans, Ubuntu, Cantarell, "Helvetica Neue", sans-serif;
  font-size: 18px;
  line-height: 1.5;
  --wp--style--block-gap: 2em;
}

p {
  line-height: 1.8;
}

.editor-post-title__block {
  margin-top: 2em;
  margin-bottom: 1em;
  font-size: 2.5em;
  font-weight: 800;
}