Customizing Slack’s themes and appearance allows users to personalize their workspace for better visual comfort, organization, and branding. While Slack’s recent redesign has limited some legacy customization options, there are still multiple ways to adjust themes, colors, and accessibility settings across desktop and mobile platforms. The most effective methods include using Slack’s built-in theme presets, creating custom color schemes with hex codes, and leveraging third-party tools like Chrome extensions or CSS edits for advanced modifications. Users can also organize workspaces by assigning distinct themes to each, improving navigation efficiency.

Key takeaways from the sources:

• Slack now offers preset themes (light/dark modes) and limited custom color options after its redesign, replacing the older fully customizable system ^[2][5][10].
• Third-party tools like Chrome extensions or direct CSS edits enable deeper customization, including dark themes and background modifications ^[6].
• Mobile customization is more restricted but includes accessibility adjustments like text size and haptic feedback ^[7].
• Workspace organization can be enhanced by assigning unique themes to different workspaces, using hex color codes for branding or visual distinction ^[5][9].

Customizing Slack’s Themes and Appearance

Using Slack’s Built-In Theme Settings

Slack’s native theme customization options are accessible through the desktop app’s preferences menu, though recent updates have reduced some flexibility. Users can still select from preset themes or create limited custom color schemes, which is particularly useful for differentiating between multiple workspaces or aligning with company branding.

To access these settings:

1. Click your profile picture in the top-right corner of the Slack desktop app.
2. Select Preferences, then navigate to the Themes tab ^[10].
3. Choose between basic light/dark themes or explore additional presets like "Arc," "Atom One Dark," or "Arizona State University" ^[1][8].

For custom themes:

• Click "Create a custom theme" and input hex color codes for the sidebar, active items, and message hover states ^[5][9].
• Example: A custom theme might use 3D3D3D for the sidebar and FF6B6B for active items, as shown in GitHub’s theme repository ^[9].
• Changes apply immediately, and themes can be shared with teammates by exporting the hex values ^[4].

Limitations:

• The 2023 redesign removed full RGB color sliders, replacing them with hex-code inputs only ^[2][3].
• Some users report that legacy custom themes no longer work, though presets remain available ^[3].
• Mobile apps offer no theme customization beyond accessibility settings like text size ^[7].

Advanced Customization with Third-Party Tools

For users seeking deeper personalization, third-party methods like Chrome extensions or direct CSS modifications provide workarounds to restore or enhance Slack’s appearance. These approaches are technical but enable features like true dark mode, custom backgrounds, and sidebar styling that Slack’s native settings no longer support.

Chrome Extensions:

• The Stylus extension (or similar tools) allows users to inject custom CSS into Slack’s web app. A popular script by Bill Hedworth, available on GitHub, enables a true dark theme and other visual tweaks ^[6].
• Steps to apply: 1. Install Stylus for Chrome or Firefox. 2. Add the Slack dark theme CSS from Hedworth’s GitHub repository. 3. Refresh Slack to see changes, which include adjusted contrast and reduced eye strain ^[6].

Direct CSS Editing (Desktop App):

• Advanced users can modify Slack’s app.asar file to alter the interface: 1. Locate Slack’s resources folder (path varies by OS). 2. Edit the CSS file to change elements like the sidebar background or message bubbles ^[6]. 3. Example: Adding background: 1a1a1a; to the sidebar class forces a darker shade.
• Risks: This method may break with Slack updates and requires backing up files before editing ^[6].

Community Resources:

• GitHub repositories like sachinh19/slack-themes offer pre-made themes with hex codes for easy application ^[9].
• Websites like slackthemes.net provide previews of 100+ themes, though some may not be fully compatible with the latest Slack version ^[1].

Mobile Customization: While Slack’s mobile apps lack theme options, users can adjust:

• Text size under Accessibility settings (iOS/Android) ^[7].
• Home tab layout to prioritize threads, drafts, or recaps ^[7].
• Haptic feedback (iOS only) for notifications ^[7].

Organizing Workspaces with Themes

Assigning unique themes to different Slack workspaces improves visual organization, especially for users managing multiple teams or projects. This method leverages Slack’s custom theme feature to create distinct color schemes for each workspace, reducing confusion and speeding up navigation.

Steps to implement:

1. Open Slack Preferences > Themes for a specific workspace.
2. Create a custom theme using hex codes (e.g., 4CAF50 for green accents in a "Marketing" workspace) ^[5].
3. Repeat for other workspaces with contrasting colors (e.g., 2196F3 for "Development") ^[10].

Benefits:

• Visual cues help quickly identify workspaces in the sidebar ^[5].
• Brand alignment for company-specific workspaces (e.g., using brand colors) ^[4].
• Reduced cognitive load when switching between contexts ^[8].

Example workflow from ZDNET:

• Workspace 1 (Client A): Dark blue theme (1565C0).
• Workspace 2 (Internal Team): Warm orange theme (FF9800).
• Workspace 3 (Personal): Soft purple theme (9C27B0) ^[5].

Tools to streamline this:

• Slack’s theme presets for quick setup ^[1].
• Hex color generators (e.g., Coolors.co) to create cohesive palettes ^[9].
• Team sharing by documenting hex codes in a shared document ^[4].