add a gradient background to the menu button
Remove debuggin leftover + remove redundant </input>
Merge pull request #336 from ussuri/minor-fixes

Remove debuggin leftover + remove redundant </input>
Replaced remaining <button> -> <spark-button>
Merge pull request #337 from ussuri/switch-buttons-to-spark-button

Replaced remaining <button> -> <spark-button>
convert to using css margins
Merge pull request #334 from dart-lang/menu-background

add a gradient background to the menu button