DeepSeek Harness (DSH) Web UI provides a basic agent development environment. With the default configuration, the interface style is relatively consistent. If you want to adjust the color scheme, fonts, or layout depth of the interface, you can use the DSH Pretty Extension plugin. It provides theme editing capabilities through a native settings page, rather than relying on external CSS overrides.

Plugin Purpose

This is a DSH plugin maintained by Rheasilvia, specifically designed for beautifying the theme of the DeepSeek Harness Web UI. It leverages DSH’s plugin, settings, slot, and theme APIs to add an independent editing entry point in the Web UI settings, supporting interface appearance changes from both preset and custom perspectives.

Core Features

The plugin provides the following available configuration options:

  • 28 theme presets: Includes common styles such as Ayu, Catppuccin, Dracula, GitHub, Nord, and Tokyo Night.
  • Independent palettes: You can separately configure accent color, background color, foreground color, and sidebar color in light and dark modes.
  • Live preview: While modifying settings, the sidebar, chat area, and session selection state update in real time, allowing you to preview effects without saving.
  • Typography and depth controls: Supports selecting UI and code fonts separately, and adjusting interface hierarchy (surface, borders, secondary text, hover states), with sidebar rendering at 82% opacity.
  • Accessibility fixes: Automatically makes minimal adjustments to low-contrast foreground colors to maintain at least a 4.5:1 text contrast ratio.
  • Native integration: Uses DSH’s menu system and semantic theme tokens, supporting settings persistence and version protection.

Installation and Enablement

Before installing, ensure your environment meets the following conditions:

  • DeepSeek Harness is installed and the web profile is configured.
  • pnpm is available in the system PATH (because dsh plugin relies on pnpm to manage dependencies).

Run the following command to install the plugin:

dsh plugin --profile web add github:Rheasilvia/dsh-pretty-extension

After installation, the plugin is disabled by default. You need to restart the DSH Web process to make it take effect:

dsh web

Usage Steps

  1. Start DSH Web and access its loopback address (usually http://127.0.0.1:3080).
  2. Open the Settings menu and select Pretty.
  3. Turn on the Enable Pretty theme switch.
  4. Switch to Light or Dark mode, choose a preset theme, or manually adjust colors, fonts, and interface effects.
  5. After confirming the desired effect in the preview area, click Save and apply.

Notes and Configuration

  • Disabled by default: The plugin does not immediately change the interface after installation; it must be manually enabled in the settings.
  • Persistent storage: Configuration information is stored under the ui-pretty.theme namespace in the $DSH_HOME/settings.yaml file. Clicking “Restore defaults” removes this configuration override and restores the native DSH theme.
  • Local font limitations: To load system fonts, the browser must support this feature and either run on a loopback address or in a secure context (HTTPS), with explicit authorization required.
  • Read-only limitation: If the browser does not access DSH through a loopback address (such as 127.0.0.1), Pretty settings will be read-only in the current session. This is a security design, and remote sessions only use in-memory settings.

Summary

DSH Pretty Extension extends the customization capabilities of the DSH Web UI through a plugin-based approach. It is suitable for developers who need to adjust the visual experience during extended use of DSH, providing a complete workflow from quick preset application to fine-grained pixel-level tuning.