Arun,
First I would check to see if they know HTML or if they say they do. A lot of students are just good at school and following directions and I had a couple students say they “knew” it, but could just play around and get it to work, not really understanding the structure and syntax. Using other tutorial sites like Khan Academy and General Assembly Dash, I could put students on those to test knowledge because they don’t let you advance until you get it “right” vs the student choice our students have in Code.org curriculum.
If they truly know HTML, awesome. I’ve had students move ahead and create Screencast tutorials to help classmates, and also go out into the community to make a website for local businesses. It’s a great opportunity for real life practice with feedback that isn’t from peers or a teacher - a business is going to have very precise needs. If you don’t have any businesses around or school is a closed campus, think about making fake businesses with customer bases that are outside the norm OR have students re-design existing webpages.
In the CSS lessons in Unit 2, they give a reference to CSS Zen Garden which is my favorite website to use because it shows the same content over and over but with radically different stylings, so you might be able to use that as inspiration.
Let me know if this helped!
Brad