Under the HTML file, we created a header for the menu. under the header created a "checkbox" and "label" for click on a button to open a menu. Menu will open with a slide down effect.
Below is the code for the header:-
In the CSS file create a style for the element by adding a background, colors and other styles. I have used adjacent sibling combinator selector that allows you to select an element that is after another specific element. When you click on a checkbox the label will be clicked automatically. This will help you to create a click function in CSS3.