Product landing page advice plus feedback very welcomed

So everything passes. But I am not ready to turn it in. I still need to work on some of the styling. Plus this is all new to me still. I feel like a cook who just through everything in a pot hoping to come out with something good. So I will look to clean up and adjust some stuff. But my buttons on the bottom I am having trouble trying to align them well. So they have a better appearance.
I am open to all advice, criticism, and feedback.
And it is much appreciated.

,https://codepen.io/gabeskates/pen/LMGWMb

I agree about the submission buttons, they need a little more styling and to be centered. But overall the design looks good.

thank you. I am trying to figure out centering the buttons. Fingers crossed

You are closing wrong way the .box1.

It should be like:

.box1 {

    border-color: black;
    border-width: 2px;
    border-style: solid;
} 
  #btn1 {
   
  font-weight:bold;
  font-size: 1em;
    padding: 4px;
    display: block;
    margin: 10px auto;
 } 

similar for the other boxes.
Happy coding