Empty menu messes with content visibility

[ithacasnowman]

To reproduce, take out the menu by doing one of these:

• Comment out the menu in _config.yml
• Comment out all the menu options in _config.yml
• Comment out site-nav in header.html
• Remove class menu-item from <li class="menu-item menu-item-{{ itemName }}"> in header.html

The associated content (posts etc) in index.html disappear (they're still around but you can't see them).

[Simpleyyt]

You can set use_motion: false to temporary fix this.