.column {
  width: 100%;
}

@media (min-width: 600px) {
  .column {
    width: 50%;
  }
}

<div class="grid-container">
    .item1 { grid-area: header; }
	.item2 { grid-area: math; }
    .item3 { grid-area: Three; }
    .item4 { grid-area: Retrieve; }
    .item5 { grid-area: clear; }
    .item6 { grid-area: textBox; }
    .item7 { grid-area: footer; }
    .item8 { grid-area: mySQL1; }
    .item9 { grid-area: BlogAttempt; }
    .btn1 {background: green; color: black; font-size: 48px; width: 95%; height: 95%; }
    .btn2 {background: black; color: yellow; font-size: 48px; width: 95%; height: 95%; }

    .grid-container 
	{
      display: grid;
      /*    width: 1200px;    */
      grid-template-columns: 1fr 1fr 1fr 1fr;
      grid-template-areas:
	  'header header header header'
      'Three Retrieve BlogAttempt BlogAttempt'
      'clear math BlogAttempt BlogAttempt'
      'footer footer footer footer';
      gap: 5px;
      background-color: #2196F3;
      padding: 20px;
    }

    .grid-container > div 
	{
      background-color: rgba(255, 255, 255, 0.8);
      text-align: center;
      padding: 1% 0;
      font-size: 24px;
    }

    #hoop-canvas 
	{
	  border: 2px dotted #000000;
      background-color: #FFFDAF;  /*light yellow*/
			/*border-radius: 5px; */
			cursor: crosshair;
      /*width: 100%;
      height: 100%;*/
    }

	#header {background-color:black; color:green; clear:both; text-align:center; padding:5px; }
	#submitBtn {background-color: #ff0000; font-size: 60px; width: 90%; height: 95%; } 
	#math {background-color: yellow; color: blue; }
	#clear {background-color: #ff0000; font-size: 48px; width: 95%; height: 95%; } 
	#postData {background-color: #ff0000; font-size: 48px; width: 90%; height: 95%; } 
	#transf {background-color:black; color:green; clear:both; text-align:center; padding:5px; }

	#tens 
    {
      font-size: 48px
    }
	#ones 
	{
      font-size: 48px
    }

	#data
    {
	  width: 95%;
	}

</div>