#showdiv { border:solid 1px; border-radius:10px; width:320px; height:400px; text-align:center; margin:auto; margin-top:50px; background-color:whitesmoke; } input[type=text] { margin-top:20px; width:290px; height:34px; font-size:20px; font-family:"微软雅黑"; } input[type=button] { width:60px; height:60px; margin-top:20px; margin-left:5px; margin-right:5px; border-radius:90px; font-size:20px; } input[type=button]:hover { width:60px; height:60px; margin-top:20px; margin-left:5px; margin-right:5px; border-radius:90px; font-size:20px; border-color:blue; }
计算器的简单使用加减乘除的使用