Dark Mode Support Checker
Paste a complete HTML document or a fragment with styles. The browser checks common dark mode signals and renders isolated light and dark previews without uploading your code.
A QUICK WALKTHROUGH
How to use this tool
- Paste HTML/CSS up to 500 KiB.
- Run the local dark mode checklist.
- Review findings and compare the isolated light and dark previews.
Signals, not a full audit
The checklist looks for common implementation signals such as prefers-color-scheme, CSS variables, color-scheme, adaptive SVGs, image handling, transitions, and a manual theme hook. It does not prove every component is accessible.
Local previews
The browser renders the pasted document in isolated light and dark preview frames. No code is uploaded, stored, or sent to a service.
Bounded input
Input is limited to 500 KiB. Scripts are removed before preview rendering so the preview remains a passive visual check.
GOOD TO KNOW
Common questions
Does this change my website?
No. It only inspects pasted text and creates temporary local previews in this browser.
Does a passing score prove dark mode is accessible?
No. Review actual content, focus states, contrast, images, and interaction states as well.