.square_contents {
display: flex;
flex-wrap: wrap;
max-width: 600px;
}
.square_contents div {
position: relative;
width: 31%;
background: #ffb6c1;
margin: 1%;
}
.square_contents div::before {
content: "";
display: block;
padding-top: 100%;
}
.square_contents p {
position: absolute;
top: 50%;
left: 50%;
transform: translate(-50%,-50%);
}