#topLevelContainer{
    display: flex;
    position: absolute;
    flex-direction: column;
    justify-content: center;
    align-items: center;

    background-image:url('./thinker16x9.jpg');
    background-position: center;
    background-size:cover;
    background-repeat: no-repeat;
    /*background-attachment: fixed;*/
    height: 100vh;
    width:100%;
    z-index:2;
    
   
}

#instructions{
    text-align: center;
    width: 50%;
    z-index: 3;
    margin: 1vh auto;
}

#darkOverlay{
    position:absolute;
    top: 0px;
    left: 0px;
    width: 100vw;
    height: 100vh;
    background: rgba(40,40,40,.5);
    z-index:1;
}


.btn{
    width:20vw;
    margin: 5px;
    z-index: 3;
}

#sudoku-grid{
    padding: 2vw;
    background: rgba(200,200,200,.5);
    -webkit-backdrop-filter: blur(10px);
    backdrop-filter: blur(10px);
    border-radius: 1vw;
    z-index: 3;
    
}

.C1, .C2, .C3, .C4, .C5, .C6, .C7, .C8, .C9, .F1, .F2, .F3, .F4, .F5, .F6, .F7, .F8, .F9 {
    border-bottom: 3px solid black !important;
    
  }
  
  
  .A3, .B3, .C3, .D3, .E3, .F3, .G3, .H3, .I3, .A6, .B6, .C6, .D6, .E6, .F6, .G6, .H6, .I6 {
    border-right: 3px solid  black !important;;
  }