The margin property with value auto is used to horizontally center the element within its container. You can try to run the following code to implement margin: auto;
Example
<!DOCTYPE html> <html> <head> <style> div { width: 200px; margin: auto; border: 2px dashed blue; } </style> </head> <body> <p>This is demo text</p> <div> This is horizontally centered because it has margin: auto; </div> </body> </html>