CSSソースは外部ファイル(sample.css)に記述 div.sample { background-color:blue; width:200px; height:50px; transition-property: background-color, width, height; transition-duration:1s; transition-timing-function:ease-in-out; transition-delay:3s; } div.sample:hover { background-color:aqua; width:300px; height:100px; } HTMLソース <html> <head> <link rel="stylesheet" href="sample.css" type="text/css"> </head> <body> <d