*, *::after, *::before {
    box-sizing: border-box;
  }
  
  /* root vars */
  :root {
      /* cell size for both width and height */
    --cell-size: 100px; 
    /* mark size for X's and O's, we want it to be 60% of the cell size*/
    --mark-size: calc(var(--cell-size) * .6);
  }
  
  body {
    margin: 0;
    background: #e0e0e0;

  }

  .board {
    width: 30rem;
    height: 60vh;
    display: grid;
    justify-content: center;
    align-content: center;
    justify-items: center;
    align-items: center;
    grid-template-columns: repeat(3, auto);
    border-radius: 50px;
    background: #e0e0e0;
    margin: auto;
    margin-top: 10em;
    box-shadow: 11px 11px 37px #b3b3b3, -11px -11px 37px #ffffff;
  }
  
  .cell {
    width: var(--cell-size);
    height: var(--cell-size);
    display: flex;
    justify-content: center;
    align-items: center;
    position: relative;
    cursor: pointer;
    border-radius: 20px;
    background: #e0e0e0;
    box-shadow: inset 9px 9px 21px #a8a8a8, inset -9px -9px 21px #ffffff;
    margin: 5px;
  }
  
/* if you hover over an x-cell or a circle-cell ie a cell that already has an element in it the cursor will be- not allowed  */
  .cell.x,
  .cell.circle {
    cursor: not-allowed;
  }
  
  /* setting actual color of x b4 and after and the outer circle(b4) to black */
  .cell.x::before,
  .cell.x::after,
  .cell.circle::before {
    background-color: black;
  }
  
  /* changing the color of hover x and o to lightgrey */
  .board.x .cell:not(.x):not(.circle):hover::before,
  .board.x .cell:not(.x):not(.circle):hover::after,
  .board.circle .cell:not(.x):not(.circle):hover::before {
    background-color: lightgrey;
  }
  
  /* creating the X mark ( not-hover = only apply this hover effect on x and circle cells when we do not have an x or a circle inside ) */
  .cell.x::before,
  .cell.x::after,
  .board.x .cell:not(.x):not(.circle):hover::before,
  .board.x .cell:not(.x):not(.circle):hover::after {

    /* make content empty */
    content: '';

    /* position it absolute to make it look better after the transformation */
    position: absolute;

    /* make the x mark width 15% of the mark size */
    width: calc(var(--mark-size) * .15);

    /* height = marksize */
    height: var(--mark-size);
  }
  
  /* rotating on part of X */
  .cell.x::before,
  .board.x .cell:not(.x):not(.circle):hover::before {
    transform: rotate(45deg);
  }
  
  /* rotating other part of X */
  .cell.x::after,
  .board.x .cell:not(.x):not(.circle):hover::after {
    transform: rotate(-45deg);
  }
  

  /* getting the circle shape (not-circle-hover =  when we're on a board that has the circle class we wanna get the cells inside that re not already a circle ) */
  .cell.circle::before,
  .cell.circle::after,
  .board.circle .cell:not(.x):not(.circle):hover::before,
  .board.circle .cell:not(.x):not(.circle):hover::after {
    content: '';
    position: absolute;
    border-radius: 50%;
  }
  
  .cell.circle::before,
  .board.circle .cell:not(.x):not(.circle):hover::before {
    width: var(--mark-size);
    height: var(--mark-size);
  }
  
  .cell.circle::after,
  .board.circle .cell:not(.x):not(.circle):hover::after {

    /* width and heigh of the after pseudo will be 70% of the mark size */
    width: calc(var(--mark-size) * .7);
    height: calc(var(--mark-size) * .7);
    background-color: white;
  }
  

  /* winning modal */
  .winning-message {
      /* display will be visible when game ends */
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    /* black with 90% transparency */
    background-color: rgba(0, 0, 0, .9);
    justify-content: center;
    align-items: center;
    color: white;
    font-size: 5rem;
    flex-direction: column;
  }
  
  .winning-message button {
    font-size: 3rem;
    background-color: white;
    border: 1px solid black;
    padding: .25em .5em;
    cursor: pointer;
  }
  
  .winning-message button:hover {
    background-color: black;
    color: white;
    border-color: white;
  }
  
  /* class of show will be applied at the end of game */
  .winning-message.show {
    display: flex;
  }