As far as I see,

• The visual mode isn’t better: a visual draft is also white-on-white (except for links and when selected).
• The currently not selected tab, as well as all toolbar buttons are black-on-black (unless hovered).

Source mode	Visual mode

In T367432#9889565, @Tacsipacsi wrote:

As far as I see,

• The visual mode isn’t better: a visual draft is also white-on-white (except for links and when selected).
• The currently not selected tab, as well as all toolbar buttons are black-on-black (unless hovered).

Source mode	Visual mode

This should be covered by T366197: VisualEditor should use Codex design tokens for custom colors

As far as I know, the source mode input box is also a VisualEditor (2017WTE) input – unless the source mode toolbar is turned off, in which case it’s an OOUI textbox, and is at least readable:

So then only the preview is a task specific to DiscussionTools?

Yeh looks like it. If you add the following rule it fixes the input areas:

.ve-ui-targetWidget:not(.oo-ui-pendingElement-pending) {background: var(--background-color-base); }

Devs feel this is better estimated when VisualEditor is resolved.