Search box unusable due to colors

🐛 bug report

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• I have read the Contributing Guidelines for this project.
• [ x I agree to follow the Code of Conduct that this project
  adheres to.
• I have searched the issue tracker for an issue that matches the one I want
  to file, without success.

Description of the problem

At https://codesandbox.io/examples/package/@stencil/core

The text color inside the search box at the top right of the page is a super-light almost-white gray on white background, making it impossible to read.

How has this issue affected you? What are you trying to accomplish?

search for something at https://codesandbox.io/examples/package/@stencil/core

To Reproduce

1. go to https://codesandbox.io/examples/package/@stencil/core
2. Click on the search box at the top right of the screen
3. type something

Expected behavior

I should be able to read what I typed

Observed behavior

It's impossible to read what I typed because the text is almost white on a white background.

Also the blue text of the link just next to it to the right: that's slightly more visible (at least you do see there's something there) but still way too difficult to read.

Link to sandbox: link (optional)

Your Environment

Start by reproducing the search box problem at https://codesandbox.io/examples/package/@stencil/core in Chrome on Linux, then inspect the page's search box and adjacent link styles. Done means typed text and the neighboring link are readable against their background, with the reported reproduction steps no longer showing the contrast problem.