内容来自对《CSS世界》学习代码的理解简化：
<!DOCTYPE html> <html> <head> <style> div { padding-top: 20px; padding-bottom: 20px; text-align: center; } dot { display: inline-block; height: 1em; line-height: 1; text-align: left; vertical-align: -.25em; overflow: hidden; } dot::before { display: block; content: '...A..A.'; white-space: pre-wrap; animation: dot 3s infinite step-start both; } @keyframes dot { 33% { transform: translateY(-2em); } 66% { transform: translateY(-1em); } } </style> </head> <body> <div>正在加载中<dot>...</dot></div> </body> </html>