a.表格边框
table,th,td{
    border:  1px black solid;
}
b.折叠边框(边款细线)
table,th,td{
    border:  1px black solid;
}
table
{
    border-collapse:collapse;
}
c.表格宽度和高度
/*表格宽度和高度*/
table
{
    width:100%;
}
th
{
    height:50px;
}
d.表格文字对齐
td
{
    text-align:right;
}
td
{
    height:50px;
    vertical-align:bottom;
}
e.表格填充
td
{
    padding:15px;
}
f.表格颜色
table, td, th
{
    border:1px solid green;
}
th
{
    background-color:green;
    color:white;
}

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>表格</title>
    <link rel="stylesheet" href="demo.css">
</head>
<body>
<table>
   <tr>
       <th>序号</th>
   </tr>
    <tr>
        <td>1</td>
    </tr>
</table>
</body>
</html>
/*表格边框*/
table,th,td{
    border:  1px black solid;
}
/*折叠边框(边款细线)*/
table
{
    border-collapse:collapse;
}
/*表格宽度和高度*/
table
{
    width:100%;
}
th
{
    height:50px;
}
/*表格文字对齐*/

/*td*/
/*{*/
    /*text-align:right;*/
/*}*/
td
{
    height:50px;
    vertical-align:bottom;
}
/*表格填充*/
td
{
    padding:15px;
}
/*表格颜色*/
table, td, th
{
    border:1px solid green;
}
th
{
    background-color:green;
    color:white;
}