APPWTV-45 UI optimizations: fixed CSS mask-images; set a handler for viewport resize event that preserves the ratio of body-font size and client width. Although improvable, this mechanism ensures font-size is larger on high resolution monitors. It works because all the width and font-size properties of CSS are in em or %. Beware: there is no lower limit -> very small screen will get tiny fonts. Same mechanism on the phone UI, but with different ratios