SharePoint site theme: Add a custom theme using PowerShell

In this blog, we will be learning how to create a custom theme for SharePoint Online.

Now SharePoint has a Site theming feature for applying custom styles and colors to the site. There are six light and two dark themes available by default. This feature provides the ability to define custom themes and make them available to site owners. Creating a custom theme in SharePoint is a quick and easy way to give your site a unique look and feel.

Currently, no theme is available under the "From your organization" option.

The steps to add a custom theme to SharePoint Online.

Step 1: Create a new color theme in SharePoint Online.

Themes are defined in a JSON schema that stores color settings and related metadata for each theme. Create a new custom theme for SharePoint Online using Microsoft Fluent UI Theme Designer, an online tool. Customize the theme as per your needs and click on the Export theme button. Copy and save the PowerShell output for later use.

Light Theme sample:

Dark Theme sample:

Step 2: Add a custom theme to SharePoint Online using PowerShell

First, connect to the SPO admin site using the Connect-SPOService cmdlet. The custom theme can be added to the SharePoint online tenant using the Add-SPOTheme cmdlet. This cmdlet creates a new theme or updates an existing theme. The color palette settings can be passed as either a hash table or a dictionary.

Execute the command for the light theme.

Now go to Site Settings, gear icon (⚙️) > Change the look > Theme and you'll find the newly added color theme listed under "From your organization".

Execute the same command for the dark theme.

Again, go to Site Settings gear icon (⚙️) > Change the look > Theme and you'll find the new added color theme listed under "From your organization".

When you choose a theme, color settings are instantly applied to the site so that you can see what the selected theme will look like. Select the desired theme, click Save to save your selection, or choose Cancel to revert to your current theme.

Our "Maroon - Light theme" output looks like

Our "Orange - Dark theme" output looks like

Update SP Theme
To update an existing theme (to modify some of its color settings, for example), add the -Overwrite flag to the Add-SPOTheme cmdlet.

I hope this will help all of you! 🧲
Feel free to provide feedback.

🚀 "Happy Coding" 🚀