*, *::after, *::before {
 box-sizing: border-box;
}

:root {
    --cell-size: 100px;
    --mark-size: calc(var(--cell-size) * .9);
}

body{
    margin: 0;
}

.board{
    width: 100vw;
    height: 100vh;
    display: grid;
    justify-content: center;
    align-content: center;
    justify-items: center;
    align-items: center;
    grid-template-columns: repeat(3, auto);
}

.cell {
    width: var(--cell-size);
    height: var(--cell-size);
    border: 1px solid black;
    display: flex;
    justify-content: center;
    align-items: center;
    position: relative;
    cursor: pointer;
}

.cell:first-child,
.cell:nth-child(2),
.cell:nth-child(3){
    border-top: none;
}

.cell:nth-child(3n+1){
    border-left: none;
}

.cell:nth-child(3n+3){
    border-right: none;
}

.cell:nth-child(3n+1){
    border-left: none;
}

.cell:last-child,
.cell:nth-child(8),
.cell:nth-child(7){
    border-bottom: none;
}

.cell.x,
.cell.circle{
    cursor: not-allowed;
}

.cell.x::before,
.cell.x::after{
    background-color: orange;
}

.cell.circle::before{
background-color: skyblue;
}


.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: lightgray;
}


.cell.x::before,
.cell.x::after,
.board.x .cell:not(.x):not(.circle):hover::before,
.board.x .cell:not(.x):not(.circle):hover::after{
    content: '';
    position: absolute;
    width: calc(var(--mark-size) * .15);
    height: var(--mark-size);
   
}

.cell.x::before,
.board.x .cell:not(.x):not(.circle):hover::before{
    transform: rotate(45deg);
}

.cell.x::after,
.board.x .cell:not(.x):not(.circle):hover::after{
    transform: rotate(-45deg);
}



.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: calc(var(--mark-size)  * .7);
    height: calc(var(--mark-size) * .7);
    background-color: white;
}

.winning-message{
    display: none;
   position: fixed; 
   top: 0;
   left: 0;
   right: 0;
   bottom: 0;
   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;

}

.winning-message.show{
    display: flex;
}