Themes
Themes let you change the structural appearance of your forum — layout, typography, spacing, component shape, custom fonts, and anything else CSS can express. They are installed from GitHub releases and managed from Admin → Themes.
How themes work
Section titled “How themes work”A theme is a GitHub repository containing a theme.json manifest and a theme.css stylesheet. When a theme is activated for a mode, Nexus injects theme.css as a stylesheet into every page.
Colors are not controlled by themes. The forum’s accent color and surface tints are always set by the admin from Admin → Appearance and apply on top of everything else. This means a theme looks correct regardless of which color scheme the admin has chosen — themes and colors are independent.
Themes are assigned per mode — you can set one theme for dark mode and a different one for light mode, or assign the same theme to both.
What themes can change
Section titled “What themes can change”Themes work through theme.css — a stylesheet injected into every page. There are no restrictions on what it can contain:
- Layout — sidebar width, topbar height, feed column width, right panel position
- Typography — custom fonts via
@import, font sizes, line heights, letter spacing - Spacing and shape — border radius, padding, card sizes
- Component styling — post cards, reply threads, composer, navigation, modals
- Animations and transitions — hover effects, page transitions, focus states
- Mode-specific rules — using
[data-theme="dark"]and[data-theme="light"]selectors
What themes cannot do:
- Override the admin’s accent color or surface tints — those always apply last
- Run JavaScript or server-side code
The theme store
Section titled “The theme store”Admin → Themes shows the theme store — themes listed in the shared Nexus registry. The store is fetched live from GitHub each time you open the panel.
Store entries show a banner image, the theme’s logo, name, author, version, and description. A green Installed badge appears on themes you’ve already installed.
Use the search field to filter by name or description. If categories are defined in the registry, category filter pills appear above the grid.
Installing a theme
Section titled “Installing a theme”From the store
Section titled “From the store”Click Install on any theme card. Nexus downloads the latest release from GitHub, validates theme.json, copies theme.css, and adds the theme to your installed list.
From a URL
Section titled “From a URL”Click the Install from URL tab, paste a GitHub repository URL, and click Install:
https://github.com/someone/my-nexus-themeActivating a theme
Section titled “Activating a theme”After installation, the theme card shows Dark and Light mode buttons. Click either to assign the theme to that mode. Clicking an already-active button deactivates the theme for that mode, returning to the default Nexus appearance.
Only one theme can be active per mode at a time. Changes take effect immediately.
Theme settings
Section titled “Theme settings”Some themes declare configurable settings — font choices, spacing options, layout variants. When a theme has settings, they appear on the theme card below the mode buttons. Save after changing any settings.
Updating a theme
Section titled “Updating a theme”When a newer release exists on GitHub, an Update button appears on the theme card. The theme’s mode assignments are preserved after an update.
Uninstalling a theme
Section titled “Uninstalling a theme”Click Uninstall on the theme card. If the theme was active for either mode, the forum reverts to the default appearance for that mode immediately.
Tarball cache
Section titled “Tarball cache”Like extensions, themes cache their downloaded release tarballs. After the first install, the theme loads from the local cache on server restarts — no GitHub request needed. The cache is cleared on uninstall.