flex的全部使用-526互联

<!DOCTYPE html>
<html>
    <head>
        <meta charset="utf-8">
        <title></title>
        <style>
            .w{
                display: flex;
                flex-direction: row;
                justify-content: center;
                width: 600px;
                height: 600px;
                background-color: aqua;
                /* align-items: center; //子元素 不换行 的时候使用 */
                /* align-content: space-between; /*子元素 换行 的时候使用 */ */
                /* flex-wrap: wrap; */
                
            }
            .w span{
                width: 100px;
                height: 100px;
                background-color: blueviolet;
                flex: 1;
                display: flex;
                flex-direction: row;
                justify-content: center;/*主轴 居中*/
                align-items: center;/*侧轴 居中*/
            } 
            .w span:nth-child(2){
                 flex: 3; /*占多少份*/
                    background-color: firebrick;
                    align-self: flex-end;   /* 侧轴 单独定义位置*/
            }
            .w span:nth-child(3){
                order: -1; /* 把位置提到前面 越小越靠前*/
            }
            
        </style>
    </head>
    <body>
        <div class="w">
            <span>1</span>
            <span>2</span>
            <span>3</span>
            
            <span>4</span>
            <span>5</span>
            <span>6</span>
            <span>7</span>
        </div>
    </body>
</html>