我的第一个html计算器_html/css_WEB-ITnose

<style type="text/css">body,#content,#te,#sa,#main-content,ul,li{margin:0 auto;padding:0;font-weight:bold;font-size:50px;}#content{width:300px;height:400px;border:1px solid gray;padding:0px;}.main-content{width:300px;height:250px;border:1px solid red;overflow:hidden;background-color:#BC8F8F;}#te{width:300px;height:80px;border:1px solid black;background:#FFD700;text-align:right;}.main-content ul li{list-style:none;                    width:60px;                    height:50px;                    border:1px solid black;                    border-radius:10px;                    display:block;                    float:left;                    text-align:center;                    cursor:pointer;margin:4px;background-color:#C0C0C0;}#mybtn{width:80px;height:40px;}</style><label></label><div id="content"> <div id="te"><p id="sa"></p> </div> <div class="main-content">   <ul class="ulclass">    <li>7</li>    <li>8</li>    <li>9</li>    <li>+</li>    <li>4</li>    <li>5</li>    <li>6</li>    <li>-</li>    <li>1</li>    <li>2</li>    <li>3</li>    <li>*</li>    <li>0</li>    <li>.</li>    <li>=</li>    <li>/</li>   </ul></div><input type="button" value="清除" id="mybtn"></div>