BlueprintJS is a React-based UI toolkit for the web. This library is very optimized and popular for building interfaces that are complex and data-dense for desktop applications. 

Menu Component provides a way for users to display lists of interactive items. A Menu is a list of interactive items and a menu item is an interactive item inside the menu. A menu item can be rendered using the MenuItem Component and under the hood, it uses an <a> element wrapped in a <li> tag.

React.js Blueprint Menu Component CSS Section headers:

• bp4-menu-header: This class is used to denote the heading of menu items. 

Approach: Let us create a React project and install React Blueprint module. Then we will create a UI that will showcase React.js BluePrint Menu Component CSS Section headers

Syntax:

<ul class="bp4-menu">
    <li class="bp4-menu-header">
        <h6 class="bp4-heading">**Heading**</h6>
    </li>
    <li><button type="button" 
        class="bp4-menu-item">Item 1</button></li>
    ...
</ul>

Creating React Project:

Step 1: To create a react app, you need to install react modules through the npx command. “npx” is used instead of “npm” because you will be needing this command in your app’s lifecycle only once.

npx create-react-app project_name

Step 2: After creating your react project, move into the folder to perform different operations.

cd project_name

Step 3: After creating the ReactJS application, Install the required module using the following command:

npm install @blueprintjs/core

Project Structure: After running the commands mentioned in the above steps, if you open the project in an editor you can see a similar project structure as shown below. The new component user makes or the code changes, we will be performing will be done in the source folder. 

Project Structure

Step to Run Application: Run the application using the following command from the root directory of the project:

npm start

Example 1: We are creating a UI that shows Menu Component CSS Section headers.

Output: Now open your browser and go to http://localhost:3000/, you will see the following output:

 

Example 2: We are creating a UI that shows Menu Component CSS Section headers.

Output: Now open your browser and go to http://localhost:3000/, you will see the following output:

 

Reference: https://blueprintjs.com/docs/#core/components/menu.section-headers