If you are introduced to the website world, you must have heard the three letter word - CSS. It is not one word, but short form of three words. The full form os CSS is Cascading Style Sheets. These are simple files with .css extension that contain some piece of code. The code determines how web pages are formatted and presented to the users.
You can change the color of the background using CSS, or use a background image. Background colors and background images can be applied to the entire page or to individual elements. Changing background colors on individual elements helps to add highlight and color to certain areas of the page.
Responsive web design makes web page look good using many different devices: desktops, tablets, and phones. Responsive web design uses only HTML and CSS. It is called responsive web design when you use CSS and HTML to resize, hide, shrink, enlarge, or move the content to make it look good on any screen.