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CSS

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JavaScript

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Babel includes JSX processing.

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HTML 

              
                <div id="root"></div>
!

CSS 

              
                /* Google font imports */
/* Open Sans 400 */
@import url("https://fonts.googleapis.com/css2?family=Open+Sans&display=swap");

body {
  box-sizing: border-box;
  padding: 0;
  margin: 0;
}
/* 
Style the root element to showcase the component in this demo. This is just for display purposes, and is non-essential 
*/
#root {
  width: 100vw;
  height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
  background: rgb(131, 58, 180);
  background: linear-gradient(
    38deg,
    rgba(131, 58, 180, 1) 0%,
    rgba(217, 76, 160, 1) 34%,
    rgba(252, 176, 69, 1) 100%
  );
}

/* style the component container */
.accordion_container {
  width: 300px;
  background-color: #efefef;
  box-shadow: 8px 8px 7px #454545;
  border-radius: 5px;
  overflow: hidden;
  border: 3px solid black;
}

/* style the title button of the accordion menu */
.accordion_title {
  width: 100%;
  height: 50px;
  border: none;
  outline: none;
  cursor: pointer;
  display: flex;
  justify-content: left;
  align-items: center;
  padding-left: 10px;
  font-family: "Open Sans", sans-serif;
  font-size: 16px;
  font-weight: 400;
  background-color: #ffda75;
}

.accordion_content {
  height: 0px;
  transition: height 0.3s ease-in;
}

/*  
The .show_content class is added and removed from the accordion_content div in the JSX to achieve the show and hide effect for the content when the accordion is clicked.
*/
.show_content {
  height: 150px;
  opacity: 1;
  visibility: visible;
  transition: height 0.3s ease-out;
}

/* Style the list item container divs */
.list_item_container {
  width: 100%;
  height: 50px;
  padding-left: 15px;
  display: flex;
  justify-content: left;
  align-items: center;
  border-top: 1px solid #a8a8a8;
}

/* Style the first lit item top border, makes the title look encloses without overlapping borders when the accordion is closed */
.accordion_content .list_item_container:first-of-type {
  border-top: 3px solid black;
}

/* Style the list items p text */
.list_item_container p {
  font-family: "Open Sans", sans-serif;
  font-weight: 400;
  font-size: 14px;
}

/* Style list_item text when list_item_container is hovered */
.list_item_container:hover > p {
  color: #0072c9;
}
!

JS 

              
                class AccordionMenu extends React.Component {
  constructor(props) {
    super(props);
    this.state = {
      contentVisible: true
    };
    // bind event handler methods here (defined below) for callback to work
    this.toggleContentVisible = this.toggleContentVisible.bind(this);
  }

  toggleContentVisible() {
    // called at onClick of accordion button
    // toggles contentVisible between true and false
    this.setState((prevState) => {
      return { contentVisible: !prevState.contentVisible };
    });
  }

  render() {
    return (
      <div className="accordion_container">
        <div className="accordion">
          {/* when button clicked, toggle the contentVisible value in our state*/}
          <button
            type="button"
            className="accordion_title"
            onClick={this.toggleContentVisible}
          >
            Accordion Menu
          </button>
        </div>
        {/* For the below Div hide / show:
            Using string literals, and a ternary if check on our states contentVisible value,
            we append the .show_content CSS class if contentVisible === true
            else we append the empty string if contentVisible === false
            Note: We are just combining multiple CSS classes here to create different effects
            Same as how we use CSS class combination in regular web pages to create visuals.
        */}
        <div
          className={`accordion_content ${
            this.state.contentVisible ? "show_content" : ""
          }`}
        >
          <div className="list_item_container">
            <p>Item 1</p>
          </div>
          <div className="list_item_container">
            <p>Item 2</p>
          </div>
          <div className="list_item_container">
            <p>Item 3</p>
          </div>
        </div>
      </div>
    );
  }
}

ReactDOM.render(<AccordionMenu />, document.getElementById("root"));
!
999px

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