css: Do not "cut through" a recipient's name too much

[nilmerg]

This is an attempt to solve the problem of the now indicator to cut through a recipient's name. In dark mode this isn't too obvious, but in light mode the line makes characters hard to read if they overlap.

[flourish86]

We figured, that if mixing the entry colors without transparency would prevent the hand from overlapping text.

CSS color-mix() looks promising for this and is supported widely enough.
https://caniuse.com/?search=color-mix

A text-shadow on the separate text node ("… to override rotations above") would prevent the handle from obscuring it.

To keep the now handle prominent enough the red line should overlay the gray background of the .new-rotation-content container.

All in all, I don't see a critical impact on legibility anyway. Since the handle is only 1px wide, the meaning could still be deduced from surrounding letters.

This is actually how reading works, e.g. shown by the missing letter effect