Does Filmot have a dark mode, and what other display settings are available?

Yes. Open the Settings page, set "Dark Mode" to On and click Save Settings.

The same page has these display and behaviour options:

• Delay Video Start: start playback a few seconds before the matched moment.
• Language Indicator: show languages as flags, short language codes or full language names.
• Hide and skip unavailable videos, and Metadata videos filter: control how unavailable videos are shown.
• Autoplay videos on mouse-over: play a video preview when you hover over a thumbnail, or preview image, in subtitle search results.
• Experimental Features: enables or disables experimental site features.
• Show nag message.
• Language: the language of the site interface.

Settings are stored in a cookie in your browser, so they apply only to the browser where you saved them. Reset restores the defaults.