🎨 Alignment of proof header

[rowanc1]

Thanks @tavin for pointing it out!

[rowanc1]

The screenshots are below. The dark mode is 4px more indented (but now aligned!), but I think it is more balanced than going to a smaller margin to account for the 4px border. I really like how the light-mode has turned out, and with the changes that @tavin suggested, I think that the dark mode is a bunch nicer now as well!

Curious @tavin if you have strong thoughts on direction here, I think this is an improvement. :)

@mmcky -- also if you have thoughts on color, I didn't give it to much thought beyond copying the general scheme you put together in sphinx proof.

[tavin]

I like this although I find the red a bit on the "high contrast" side. But I have my own local tweaks anyway :)

[mmcky]

thanks @rowanc1 and @tavin -- these look like nice changes.

I will take note of this PR and try and push some of these improvements into sphinx-proof as well.

[mmcky]

@rowanc1

I tend to agree with this. What if the line in dark mode is the same as the background colour in light mode (for consistency?)

I like this although I find the red a bit on the "high contrast" side.

[rowanc1]

Knocking it back a bit, much better -- good call. :)

[rowanc1]

Ok -- people on twitter also like the full border.

Merging this in!