Mailspring/docs-atom/upgrading/upgrading-your-syntax-theme.md
Ben Gotow df38008c56 fix(*): Small fixes from Lake Tahoe. See Summary.
Summary:
This diff includes a few small things:

- Menu: Don't select the first item until the user taps down arrow, and allow the user to use the arrow keys to move up and down through Menu items.

- Menu: Make scroll code from MultiselectList re-usable, use in Menu. Now if you use the keys to move to an item that is offscreen it will follow.

- Popover: Tapping the button that opened popover should close it

- Make sure buttons in toolbars are at least standard height

- Re-enable Markdown processing via `grunt docs`

- A bit of initial inline documentation for crosjdoc. Need to evaluate whether this is worth doing everywhere.

- New `search-playground` package for experimenting with search and search weights.

- Swap itemClassProvider for more generic itemPropProvider

- Add crojsdoc config file

- Export React, because third party packages can't require things from our app

- [FEATURE] Bring back static file support in third party packages via `nylas://translate/IMG_20150417_124142.jpg`

- Fix invariant error with search bar

- [FEATURE] "Show Original" under Message actions

- Fix DatabaseView so that many archives at once don't cause problems

Test Plan: Run specs

Reviewers: evan

Reviewed By: evan

Differential Revision: https://review.inboxapp.com/D1426
2015-04-22 16:41:29 -07:00

1.7 KiB

Upgrading Your Syntax Theme

Text editor content is now rendered in the shadow DOM, which shields it from being styled by global style sheets to protect against accidental style pollution. For more background on the shadow DOM, check out the Shadow DOM 101 on HTML 5 Rocks.

Syntax themes are specifically intended to style only text editor content, so they are automatically loaded directly into the text editor's shadow DOM when it is enabled. This happens automatically when the the theme's package.json contains a theme: "syntax" declaration, so you don't need to change anything to target the appropriate context.

When theme style sheets are loaded into the text editor's shadow DOM, selectors intended to target the editor from the outside no longer make sense. Styles targeting the .editor and .editor-colors classes instead need to target the :host pseudo-element, which matches against the containing atom-text-editor node. Check out the Shadow DOM 201 article for more information about the :host pseudo-element.

Here's an example from Atom's light syntax theme. Note that the atom-text-editor selector intended to target the editor from the outside has been retained to allow the theme to keep working during the transition phase when it is possible to disable the shadow DOM.

atom-text-editor, :host { /* :host added */
  background-color: @syntax-background-color;
  color: @syntax-text-color;

  .invisible-character {
    color: @syntax-invisible-character-color;
  }
  /* more nested selectors... */
}