Nonidiomatic GSRs page

[adelq]

There are a number of elements on the GSRs fragment that do not fit with Material design / Android ecosystem:

• [x] "Loading..." toast (see progress indicators)
• [ ] Non Material/native buttons (or shadows hidden, I'm not totally sure they just look out of place, buttons reference)
• [ ] Colors not in the Material palette or Labs palette or app palette (see #449, color reference)
• [x] Very small buttons (didn't even know they were clickable at first, buttons reference)
• [x] Very light fonts (I know I'm old, but not that old, the contrast ratio = 1.7, typography minimum is >4.5, recommended 7)
• [x] Back "button" in WebView (all Android phones have back built-in, this isn't iOS, see navigation)