Insufficient contrast in zed search bar option buttons on/off

When searching in zed, there are option buttons for case sensitivity, whole word, and regex. They all always look inactive to me. In other words, I don't think the background color for the enabled variant of this button has enough contrast in relation to the background color of the search input box itself.

In the below screenshot, regex is enabled, but it looks disabled to me. The only thing I can clearly see is there is a highlight color on hover, but that is only for hover.

No file, test, or entry point is named. Start by locating the Zed theme definitions for the search bar's case-sensitivity, whole-word, and regex option buttons, then compare enabled and inactive states against the input background. Done means the enabled state is visibly distinct and the contrast concern shown in the screenshot is resolved.

Written by the indexing model from the issue text.