Changed active link color to beige for mobile nav, since it's otherwise hard to know when you've clicked on it with a touchscreen.
My previous 'viewport' modifications worked. I'm now removing the HTML meta tag version, to see whether the newer CSS '@viewport' was enough.
Viewport experiment revealed that both versions of the viewport instructions are necessary under the current mixed browser standards. I'm adding the HTML meta tag version back now.
Corrected footer background at all viewport sizes.