Themes

Themes

A Kotatsu theme is a folder of colors, fonts, layout choices and pictures. There is no code inside it, so a theme can change how Kotatsu looks and nothing else.

Pick a theme

Open Settings (the gear at the top right), then Appearance. In the Theme group, choose from Theme pack.

Six packs come with Kotatsu:

Pack	What it looks like
Natsumikan	The default on a fresh install. Light. Warm cream glass with indigo ink, mikan orange for what matters and periwinkle for what you choose.
Blue Hour	A quiet blue-grey room with a lavender accent and warm rose.
Sparkle	Dark plum, re-tinted all the way through, including Kotatsu's own marks. Italics turn pink.
Natsumikan Classic	The original Natsumikan. Light. A warm cream page with indigo text.
Natsumikan Manga	Light, with a manga frame. A sunlit marigold page, indigo ink and mint at the edges.
Midnight Kissaten	Dark coffee-shop brown, with warm cream text.

A fresh install starts on Natsumikan. If you already use Kotatsu, you keep the theme you chose, and an update never changes it. The list also still holds Blue Hour (Native), the earlier default saved in SillyTavern's older theme format, above the packs. Choose the Blue Hour pack to use the pack version.

The Natsumikan packs were renamed in v0.8. What was called Natsumikan V3 is now Natsumikan. The original is now Natsumikan Classic, and Natsumikan V2 is now Natsumikan Manga. Only the names changed. If you had one of them picked, it is still picked.

Your choice is remembered. Switching themes does not change your chats.

Change how messages look

Themes set colors and surfaces. How a message is laid out is a separate choice, and it is yours. In Settings → Appearance, in the Wardrobe & Shell group, the Messages setting offers:

• Card
• Flat
• Bubble
• Script
• Split bubbles
• Portrait
• Portrait column
• Broadcast
• Sprites (visual novel): your characters stand on a stage beside the chat. See Sprites.

The same group has a Nameplate setting (inline or above the message) and a Metadata setting (always, on hover or on click).

Some themes pin a message look on purpose. When one does, your own choice is greyed out while that theme is on.

Install a theme someone sent you

1. Unzip it into your Kotatsu folder, inside data/default-user/theme-packs/. On a Windows install that is Documents\Kotatsu\data\default-user\theme-packs\. You should end up with theme-packs/their-theme/theme.json.
2. Reload Kotatsu (F5).
3. Pick it in Settings → Appearance → Theme pack.

Themes are safe to share. A theme is data only: colors, sizes, fonts and pictures from its own folder. Kotatsu refuses any theme that tries to load something from the internet or from outside its folder. The worst a theme can do is look bad.

The Import button next to the theme list is for old SillyTavern theme files. It is not for these theme folders.

Make your own

You do not need to be a programmer. If you can edit a text file and copy a color code, you can make a theme.

You need a terminal open in the Kotatsu folder and a text editor. On Windows, open the Kotatsu folder in File Explorer, click the address bar, type cmd and press Enter.

1. Make a theme. rainy-day becomes the folder name, so use lowercase letters, numbers and dashes.

   npm run theme:new -- rainy-day --name "Rainy Day"
   

   The folder appears at data/default-user/theme-packs/rainy-day/. Updates never touch it. To start from a theme you like instead, add --from midnight-kissaten (or any other pack's id). The ids did not change with the names: natsumikan is Natsumikan Classic, natsumikan-v2 is Natsumikan Manga and natsumikan-v3 is Natsumikan.

2. Open theme.json in the new folder and change two colors, background and accent. Colors are a # and six characters, such as #1a1410. The rest of the colors follow those two.

3. Check it.

   npm run theme:check -- rainy-day
   

   Every line starts with PASS, INFO, WARN or FAIL. Fix every FAIL before you share. The check also measures that your text is readable against its background.

4. In Kotatsu, press F5, then pick your theme under Theme pack.

5. Edit, save, press F5. No restart is needed. Your latest edit shows on reload.

To share a theme, zip its folder and send it.

Go further

The theme authoring guide covers everything else: how the palette grows into the full set of colors, every setting by name, adding fonts and pictures, making a theme comfortable for long sessions, and fixing common check messages. It also takes apart Kissaten Showcase, an example theme in docs/theme-examples/kissaten-showcase/. The example is not in the theme list; copy it into your own theme with npm run theme:new -- my-showcase --from kissaten-showcase.

If something goes wrong

• My theme isn't in the list. Reload with F5. Check that the folder sits directly inside data/default-user/theme-packs/ and has a theme.json in it, not inside another folder from the zip.
• I picked my theme and everything went back to Blue Hour, with a red message. Kotatsu refuses a broken theme rather than half-applying it. The message names the problem. npm run theme:check explains it in more detail.
• My edit doesn't show. Save the file, then press F5.

More are in the authoring guide's last section.

Next

• Coming from SillyTavern for what else is different.
• Glossary