The light grey text used to display the date under thread titles is a little difficult so see it would be better i think if it was a bit darker
Agreed, the size is incredibly small and contrast ratio is 2.93 (should be closer to 4.0 but less than if the "muted" style is preferred), still a lot of small improvements can be made.
For windows machines you can change font size by holding down the control key and advancing the scroller on your mouse.