# Dark Mode Every page in the Heartbeat web UI supports light mode, dark mode, and automatic (follows the OS/browser setting). Each user picks their preference independently; it is stored in the browser and takes effect immediately without a page reload. --- ## Choosing a theme Open your profile page (`/profile`) and scroll to the **Appearance** section. Click one of the three buttons: | Button | Behaviour | |--------|-----------| | **Auto** | Follows the OS or browser dark-mode preference. Updates live if the system setting changes. | | **Light** | Always light, regardless of system setting. | | **Dark** | Always dark, regardless of system setting. | The preference is stored in `localStorage` under the key `hbd_theme` and applies to the current browser only. Clearing browser storage resets it to **Auto**. --- ## Implementation notes ### No flash of unstyled content A small synchronous `