:root{
    --main-bg-color: #191919;
    --main-line-color: #5DBCF9;
}

*{
    box-sizing:border-box;
}
body{
    width:100%;
    height:100vh;
    overflow:hidden;
    display:flex;
    justify-content:center;
    flex-direction:column;
    align-items:center;
    background-color:var(--main-bg-color);
}

.square{
    position:relative;
    width:280px;
    height:280px;
}

.circle-left-top,
.circle-right-top,
.circle-right-bottom,
.circle-left-bottom{
    width:100px;
    height:100px;
    border:solid var(--main-line-color) 15px;
    border-radius:50%;
    border-bottom-right-radius: 0px;
}

.circle-right-top{
    position:absolute;
    right:0;
    top:0;
    transform:rotate(90deg)
}
.circle-right-bottom{
    position:absolute;
    right:0;
    bottom:0;
    transform:rotate(180deg)
}
.circle-left-bottom{
    position:absolute;
    left:0;
    bottom:0;
    transform:rotate(-90deg)
}
.square-center{
  position:absolute;
  left: 50%;
  top:50%;
  transform: translate(-50%,-50%);
  border:solid var(--main-line-color) 15px;
  width:110px;
  height:110px;
}