JEDWare comes in a light and a dark theme. The wallboards are always dark, so they read well on a TV. The rest of the app follows your choice.
Switch the theme
Click the switch with the sun and moon at the top right of the app, next to the help icon. The change is immediate. Click it again to go back.
On a phone, the switch sits in the user menu instead: tap your user icon at the top right and tap Switch between light and dark mode.
The choice is stored in the browser, not on your user. On another computer, or after clearing the browser data, the app opens in the light theme again.