Themeing appears is broken.

[im-sky]

Prerequisites

• Put an X between the brackets on this line if you have done all of the following:
  • Checked that your issue isn't already filed: https://github.com/cliffordfajardo/cato/issues

Description

Any changes to background colors are completely ignored.

Steps to Reproduce (including a GIF is helpful)

1. Open Cato extension's options page.
2. Change any of the color settings.

Expected behavior: The tool's preview should update based on the new color settings, and the tool itself must also reflect the new colors.

Actual behavior: The tool's preview as well as tool itself remain unchanged.

Reproduces how often: 100%

Versions & Operating System of Browser

• Version: Google Chrome Version 79.0.3945.88 (Official Build) (64-bit)
• Operating System: Windows 10 1809

Additional Information

Any additional information, configuration or data that might be necessary to reproduce the issue.