DIV水平垂直居中

<div class="father">
        <div class="son"></div>
</div>

   .father {
            margin: 0 auto;
            width: 400px;
            height: 400px;
            background-color: black;
            position: relative;
        }
        
    .son {
            width: 100px;
            height: 100px;
            background-color: hotpink;
            position: absolute;
            left: 50%;
            top: 50%;
            margin-left: -50px;
            margin-top: -50px;
        }

.father {
            margin: 0 auto;
            width: 400px;
            height: 400px;
            background-color: black;
            position: relative;
        }
        
.son {
            width: 100px;
            height: 100px;
            background-color: hotpink;
            position: absolute;
            margin: auto;
            top: 0;
            left: 0;
            right: 0;
            bottom: 0;
        }

        .father {
            margin: 0 auto;
            width: 400px;
            height: 400px;
            background-color: black;
            position: relative;
            text-align: center;
           
        }
        
        .son {
            width: 100px;
            height: 100px;
            background-color: hotpink;
            display: inline-block;
            position: absolute;
            top: 50%;
            margin-left: -50px;
            margin-top: -50px;
        }

        .father {
            margin: 0 auto;
            width: 400px;
            height: 400px;
            background-color: black;
            position: relative;
        }
        
        .son {
            width: 100px;
            height: 100px;
            background-color: hotpink;
            position: absolute;
            top: 50%;
            left: 50%;
            transform: translate(-50%, -50%);
        }

        .father {
            margin: 0 auto;
            width: 400px;
            height: 400px;
            background-color: black;
            display: flex;
            flex-direction: column;
            justify-content: center;
            align-items: center;
        }
        
        .son {
            width: 100px;
            height: 100px;
            background-color: hotpink;
        }