<div class="outerBox">
    <div class="innerBox"></div>
</div>

.outerBox {
    height: 400px;
    background-color: rgb(12, 243, 232);
    display: flex;
    justify-content: center;
    align-items: center;
}
.innerBox {
    width: 200px;
    height: 200px;
    background-color: pink;
}

.outerBox {
    height: 400px;
    background-color: rgb(12, 243, 232);
    position: relative;
}
.innerBox {
    width: 200px;
    height: 200px;
    background-color: pink;
    position: absolute;
    top: 0;
    right: 0;
    bottom: 0;
    left: 0;
    margin: auto;
}

.outerBox {
    height: 400px;
    background-color: rgb(12, 243, 232);
    position: relative;
}
.innerBox {
    width: 200px;
    height: 200px;
    background-color: pink;
    position: absolute;
    left: 50%;
    top: 50%;
    margin-left: -100px;
    margin-top: -100px;
}

.outerBox {
    height: 400px;
    background-color: rgb(12, 243, 232);
    position: relative;
}
.innerBox {
    width: 200px;
    height: 200px;
    background-color: pink;
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
}