You have a lot of syntax errors in your HTML (you can check them with the dropdown button in the upper right corner of the HTML panel and codepen will highlight them for you). This might cause weird behaviour of the CSS, especially with missing closing tags.
Also, in codepen you can’t put your whole HTML inside the HTML panel. You only put there what’s inside the <body> tag. If you want to add external scripts or other stuff that belongs in the <head>, you do that by clicking on the little cogwheel in the upper left corner.
Sorry, I put all the scripts there 'cause I didn’t want to forget them when uploading to github. And concerning the html. I saw the errors and it display this "Tag must be paired, no start tag: hr" Pls what does it mean
The code isn’t working as I expected. Pls help me implement the code and save it. Then I’ll see whether it’s nice. I want the whatsapp to still be on one line even after reducing the browser’s width. Thanks
Just use media queries for smaller screens…
remove the margin and increase width to 100%…
Play around with margin, padding and width to customize for different screen sizes.