style.css

body {
    text-align: center;
}

.score_title{
  font-size: xxx-large;  
}

canvas.board {
    background-color: lightslategrey;
    border: 1px solid ;
    border-color: black;
}

#game_over_modal {
    display: none; /* Hidden by default */
    position: fixed; /* Stay in place front is invalid - may break your css so removed */  
    padding-top: 100px; /* Location of the box - don't know what this does?  If it is to move your modal down by 100px, then just change top below to 100px and remove this*/
    left: 0;
    right:0; /* Full width (left and right 0) */
    top: 0;
    bottom: 0; /* Full height top and bottom 0 */
    overflow: auto; /* Enable scroll if needed */
    background-color: rgb(184, 21, 21); /* Fallback color */
    z-index: 1; /* Sit on top - higher than any other z-index in your site*/
}

.game_over_title {
  font-size: 120px;
  font-family: 'Black Ops One', cursive;
  line-height: 120px;
  text-align: center;
  text-shadow: 5px 5px #000000;
  color: #ffffff;
  
}


.start_over {
  margin-top: 60px;
    padding: 15px 32px;
    text-align: center;
    font-size: 40px;
    font-weight: bold;
    font-family: corbel;
    color: #ffffff;
    text-shadow: 2.5px 2.5px #000000;
    background-color: black;
    border: 2px solid;
    text-align: center;
    text-decoration: none;
    display: inline-block;
    width: 320px;
    height: 100px;
    border-radius: 32px;
    cursor: pointer;

}