CSS居中

不用float的多个div的水平居中

    <div class="parent">
        <div class="child">
            1
        </div>
        <div class="child">
            2
        </div>
        <div class="child">
            3
        </div>
    </div>

.parent {
            text-align: center;
            font-size: 0;//去除display: inline-flex;产生的间隙
        }

.child {
            font-size: 1rem;//去除display: inline-flex;产生的间隙
            width: 10rem;
            height: 10rem;
            background-color: pink;
            display: inline-flex;
            -webkit-text-size-adjust:none;
        }

image.png

        .parent {
            display: flex;
            align-items:center;
        }
        
        .child {
            margin: 0 auto;
            width: 10rem;
            height: 10rem;
            background-color: pink;
            
        }

image.png

div的垂直居中
1.display:flex;

<div class="parent">
        <div class="myself">
            <div class="child">
                1
            </div>
            <div class="child">
                2
            </div>
            <div class="child">
                3
            </div>
        </div>
    </div>

.parent {
            height: 50rem;
            background-color: yellow;
            display: flex;
            justify-content: center;
            align-items: center;
        }
        
        .child {
            /*margin: 0 auto;*/
            width: 10rem;
            height: 10rem;
            background-color: pink;
        }

image.png

2. position:absolute;+transform

.parent {
            height: 50rem;
            background-color: yellow;
            position: relative;
        }
        
        .child {
            width: 10rem;
            height: 10rem;
            background-color: pink;
        }
        .myself{
            position: absolute;
            top: 50%;
            transform: translateY(-50%) translateX(-50%);
            left: 50%;
        }

image.png