* fix(welcome-page): css tweaks in prep for branded welcome page
- Watermarks should no longer depend on toolbar size. The left watermark made
room for the toolbar when the toolbar was on the left side of the screen, but
the toolbar has been moved to the bottom. The right watermark...well it'll
clash with the vertical filmstrip but at least the margins will be consistent
with the left watermark.
- Apply new font-family so fonts are more likely to be consistent across the
app. Design likes SF UI and keeps requesting it so use it by default.
- Change sizings of welcome page header to be more responsive. This will help
the header be scrollable when there is no additional content and the header
overflows.
- Change colors of the welcome page header and remove background image that
was in the header. Leave in the dom for the background image in case other
deployments need to continue showing an image.
- Add a period to the title of the welcome page.
- Move watermarks dom location as it is not part of the header; it's part of the
whole page.
* [squash] Size and font adjustments. Renaming.