Search controls: inconsistent text-wrapping in responsive design mode

[jayaddison]

Describe the bug
The application is intended to follow responsive design principles, and should be usable and elegant on devices with constrained viewports.

Currently some of the text wrapping on the homepage is not ideal; particularly related to the dietary property checkboxes; sometimes the label text for a checkbox appears horizontically adjacent (inline) with the checkbox, and sometimes the text may wrap onto a different vertical plane from the checkbox.

To Reproduce
Steps to reproduce the behavior:

1. Visit the homepage
2. Enable responsive design mode in your browser and/or use a device with a suitably constrained viewport
3. Observe inconsistent checkbox/label-text wrapping

Expected behavior
It would be preferable for the the text labels always to appear inline to their corresponding checkbox - that is, at the same vertical position on the page.

Screenshots

[jayaddison]

Pull request #281 seemed to improve this on some devices, but not all; some further investigation could be helpful.