First of all good job. Nice, clean layout. I have a few suggestions:
Aesthetics:
A very slight enlargement of the Whonix logo.
I feel the light blue backdrop of the top banner is a bit over used by software sites in general see: https://syncthing.net/. Can you please try a mock-up with a light green gradient? The download button is good as it is.
The light brown bottom banner in the bottom can benefit from changing to a shade of green matching the top banner - solid fill not gradient.
The icon for “isolation” can look like a vault door.
The compatibility icon can have a miniature Debian logo on it cut out like stencil on the puzzle piece.
Wording:
“Keep your anonymity with Whonix” can be better read “Protect your privacy with Whonix”
Avoid the word free because its ambiguous →
“A libre software and open network…”