CSS类选择器 ·类选择器以一个点号显示 ..center {text-align:center} <h1 class="center">This heading will be center-aligned </h1> <p class="center"> This paragraph will also be center-aligned. </p>• 类选择器以一个点号显示 • .center {text-align: center} <h1 class="center"> This heading will be center-aligned </h1> <p class="center"> This paragraph will also be center-aligned. </p> CSS 类选择器