body{
    margin:0;
    padding:0;
    display: flex;
    justify-content: center;
    align-items: center;
    flex-direction: column;
    height: 100vh;
    background-image: url("images/bg.jpg");
}
#gameboard{
    width: 300px;
    height: 300px;
    background-color: black; 
    display: flex;
    flex-wrap: wrap;
    border:solid 1px green;
}
.square{ 
    width: 100px;
    height: 100px;
    background-color: aqua;
    border : solid 2px green;
    box-sizing: border-box;
    display: flex;
    justify-content: center;
    align-items: center;
} 
.circle{
    height: 90px;
    width: 90px;
    border-radius: 50%;
    border: 15px solid blue;
    box-sizing: border-box;
}
.cross{
    height: 90px;
    width: 90px;
    position: relative;
    transform: rotate(45deg);
}
.cross::before ,.cross::after{
   content: "";
   position: absolute;
   background-color: red;
}
.cross::before{
    left:50%;
    width:30%;
    margin-left: -15%;
    height: 100%;
}
.cross::after{
    top:50%;
    height:30%;
    margin-top: -15%;
    width: 100%;
}