setting defaultTheme has no effect

[mikefarmer01]

Setting params.defaultTheme in ./config/_default/config.toml has no effect. No matter whether set to "dark" or "light", the theme is always dark.

On the other hand, setting params.themeColor and params.themeContrast have the desired effects.

[schnerring]

Theme selection is a bit convoluted, I probably should add some explanations somewhere.

When the site initially loads, it will set theme attribute of the html properly:

https://github.com/schnerring/hugo-theme-gruvbox/blob/dbf1af452041c500e276dd6589963b081769c849/layouts/_default/baseof.html#L2-L5

Inside dark-mode.js this behavior is overriden by the following logic:

https://github.com/schnerring/hugo-theme-gruvbox/blob/dbf1af452041c500e276dd6589963b081769c849/assets/js/dark-mode.js#L1-L31

1. Check whether a preferred theme is stored inside local storage. This will always have a value after the page loaded for the first time (Initial Load). So if you debugged the page and set defaultTheme after, you'll have to delete cookies/site data.
2. Also, if the browser supports it, the OS theme-preference is checked which overrides defaultTheme. If you want to test this, disable JavaScript.
3. If neither (1) and (2) (Undefined) are true, the defaultTheme will be displayed.

[mikefarmer01]

Understood.
So in my case, it's because the brower's default theme.

Thanks for the detailed explanation. Where should it be documented?

[schnerring]

The README or the code/config file.