@Kassatay if you just change the background color it will be fine . Additionally, you may add {resize : none } in your textarea css. It will prevent resizing the textarea. Rest of your project is looking fine.
Your form looks good @Kassatay. Some things to revisit;
When using codepen it only expects the code you’d put within the <body> </body> element in HTML. (No need to include the body tags). For anything you want to add to <head> click on the ‘Settings’ button, then HTML and add it into the ‘Stuff for <head>’ box.
The link to your font would go in the box labeled ‘Stuff for <head>’
Don’t use <br> to force spacing. Use margin and/or padding in CSS.
Codepen provides validators for HTML, CSS and JS. Click on the down arrow in the upper right of each section and then click on the respective ‘Analyze’ link.
The HTML one misses a lot of errors which is why I recommend W3C
The CSS one is good. Run it, you have a typo you need to correct.