One of the possible reasons that it mess up your website web design, is that you are using not the latest Turn Off the Lights browser extension version on your favorite web browser. And that the “Flash Detection” feature is enabled in the Turn Off the Lights options page. In addition, this can cause some z-level issues with not the latest and modern HTML5 websites.

Fix this messes up the web design
You can experience this messes up the web design if you use not the latest web browser version. Or that you enable the “Flash Detection” feature. To fix this issue go and reinstall the Turn Off the Lights browser extension from the official website. And disable the “Flash Detection” in the options page, tab “Advanced Options”.
Google Chrome, Firefox, Microsoft Edge
If you are a Chromium user (Google Chrome, Opera, Microsoft Edge, Yandex) or a Firefox user. You can follow this instruction steps:
- Click right on the gray lamp button in your web browser toolbar.
- Select Options from the context menu
- From the right sidebar, select the tab Advanced Options
- And select the radio button from the Flash Detection feature to disabled
- Restart your current web page
Safari
For the Safari users on macOS 10.12 or higher can follow this instruction steps:
- Open the “Turn Off the Lights for Safari” from the Launchpad
- And click on the gray button Options
- The Turn Off the Lights Options page window shows up and select the tab Advanced Options
- Select now the radio button to disable the Flash Detection feature
- Refresh your current web page
Did you find technical, factual or grammatical errors on the Turn Off the Lights website?
You can report a technical problem using the Turn Off the Lights online technical error feedback form.