<!DOCTYPE html> <html> head> meta charset="utf-8" /> name="viewport" content="width=device-width,initial-scale=1"title>我是中国人</> <!-- 新 Bootstrap 核心 CSS 文件 --> link href="css/bootstrap.min.css" rel="stylesheet" 最新的 Bootstrap 核心 JavaScript 文件 script src="js/bootstrap.min.js"></script="https://cdn.staticfile.org/popper.js/1.15.0/umd/popper.min.js"style type="text/css"> .pull-left { width: 200px; height background-color red; } .pull-right yellow} stylebodydiv id="" class="container"> ="pull-left"> pull-left div="pull-right" pull-right >