We should not hardcode a default text colour to white, especially in light
mode. This is the (temporary) cause of many issues like containers#7708 where we
hadn't yet set a light mode color so you get white on light.

We don't have a 'default text color' and none of the existing palette
entries fit, so I talked to Emma and decided to create a new variable.

Unfortunately, even though this is a 'correct' change, setting it right
now has the reverse problem: anything that is still missing light mode
support will see the default text color change from white to dark and
have problems on dark backgrounds. A quick test showed the following:

- some forms (containers#7214)
- containers#7727
- containers#7728

So we should not move this out of draft until most of these are fixed,
and definitely not immediately before a release. In the meantime, it's
handy to set this to something really obvious (e.g. amber) to see what
still needs light mode support.

Fixes containers#7724.

Signed-off-by: Tim deBoer <[email protected]>

Initial light mode support for container and Kubernetes details screens.

Just removed two hardcoded dark mode colors: charcoal header and zinc
summary page. Set the same text color as other Summary pages to make the
text visible.

For editing there is no great place to set the text color until containers#7214
and containers#7547 are in, so for now the text color is set 'manually' using a
div.

Fixes containers#7731.

Signed-off-by: Tim deBoer <[email protected]>