一响应式布局
@media
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>Title</title> <style> .c1 { background-color: red; height: 50px; } /*大于700宽度生效*/ @media (min-width: 700px) { .c2 { background-color: blue; } } </style> </head> <body> <div class="c1 c2"></div> </body> </html>