一：
要想使用弹性盒子布局，首先就要把这个盒子变为一个弹性盒子，(display:flex)
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<html><head><meta charset="utf-8"><title></title><style>/* 首先将该盒子变为一个弹性盒子 */.box{display: flex;/* 指定盒子的排列方式 列 row是横着排 */flex-direction: row;width: 1200px;height: 100px;background-color: #228B22;/* 水平居中 */justify-content:space-around ;/* justify-content:flex-end是右对齐justify-content:flex-start是左对齐*//* 垂直居中 */align-items: center;}.item{width: 100px;height: 50px;border: 1px solid red;}</style></head><body><div class="box"><div class="item">item1</div><div class="item">item2</div><div class="item">item3</div><div class="item">item4</div><div class="item">item5</div><div class="item">item6</div><div class="item">item7</div><div class="item">item8</div><div class="item">item9</div><div class="item">item10</div></div></body>
</html>