知识点 justify-content: center//子项在flex容器水平居中 align-items: center//子项在flex容器垂直居中
代码块
<div class="main"> <div class="maincon"> </div> </div> .main{ width: 100vw; height: 100vh; display: flex; align-items: center; justify-content: center; } .maincon{ width:400px; height:200px; background: #314057; }