Why top solutions not accurate ?

[FranckSix]

For example:
Daily challenge for october 7, 2025

Is what I see in Firefox
Score: 706.34 {139}, 100% match ???

Players should at least be given the option to filter out results that benefit from browser flaws, so that only the real CSS solutions are displayed. For training and learning purposes.

[ludviglindblom]

CSS Battle is not for training and learning CSS, it's for code golfing.
And it's made abundantly clear from the FAQ that the scoring is done on Chromium, so using Firefox is not a good idea for CSS Battle.

https://cssbattle.dev/faqs

Submitted code solutions are rendered in a headless Chromium browser on a Ubuntu 18.04 server.

Your code is rendered as it is without any modification and the browser settings are all set on default.

There might be slight differences in how different browsers render your code in the game preview. Hence till the time we find a way a reliable way to normalize these differences, we recommend playing on Chrome, Chromium, Brave or Safari browser (these are the ones we have tested).