Help me in solving HTML50 problem

My issue

CSS can be written in-line, as an internal stylesheet within the html file as well as an external stylesheet.
External stylesheets are the preferred method for today’s web development practices
The external stylesheet code is stored in a file with a .css extension
An internal stylesheet is written using the element inside the element of an HTML file
Click on ‘Next’ to continue.

My code

// your code goes here

Learning course: Learn HTML / CSS
Problem Link: Recap Practice Problem in Learn HTML / CSS - CodeChef