//源码
table {
 background-color: transparent;
}
caption {
 padding-top: 8px;
 padding-bottom: 8px;
 color: #777;
 text-align: left;
}
th {
 text-align: left;
}
.table {
 width: 100%;
 max-width: 100%;
 margin-bottom: 20px;
}
.table > thead > tr > th,
.table > tbody > tr > th,
.table > tfoot > tr > th,
.table > thead > tr > td,
.table > tbody > tr > td,
.table > tfoot > tr > td {
 padding: 8px;
 line-height: 1.42857143;
 vertical-align: top;
 border-top: 1px solid #ddd;
}
.table > thead > tr > th {
 vertical-align: bottom;
 border-bottom: 2px solid #ddd;
}
.table > caption + thead > tr:first-child > th,
.table > colgroup + thead > tr:first-child > th,
.table > thead:first-child > tr:first-child > th,
.table > caption + thead > tr:first-child > td,
.table > colgroup + thead > tr:first-child > td,
.table > thead:first-child > tr:first-child > td {
 border-top: 0;
}
.table > tbody + tbody {
 border-top: 2px solid #ddd;
}
.table .table {
 background-color: #fff;
}

//源码
.table-striped > tbody > tr:nth-of-type(odd) {
 background-color: #f9f9f9;
}

//源码
.table-bordered {
 border: 1px solid #ddd;
}
.table-bordered > thead > tr > th,
.table-bordered > tbody > tr > th,
.table-bordered > tfoot > tr > th,
.table-bordered > thead > tr > td,
.table-bordered > tbody > tr > td,
.table-bordered > tfoot > tr > td {
 border: 1px solid #ddd;
}
.table-bordered > thead > tr > th,
.table-bordered > thead > tr > td {
 border-bottom-width: 2px;
}

//源码
.table-condensed > thead > tr > th,
.table-condensed > tbody > tr > th,
.table-condensed > tfoot > tr > th,
.table-condensed > thead > tr > td,
.table-condensed > tbody > tr > td,
.table-condensed > tfoot > tr > td {
 padding: 5px;
}

//源码
.table > thead > tr > td.active,
.table > tbody > tr > td.active,
.table > tfoot > tr > td.active,
.table > thead > tr > th.active,
.table > tbody > tr > th.active,
.table > tfoot > tr > th.active,
.table > thead > tr.active > td,
.table > tbody > tr.active > td,
.table > tfoot > tr.active > td,
.table > thead > tr.active > th,
.table > tbody > tr.active > th,
.table > tfoot > tr.active > th {
 background-color: #f5f5f5;
}
.table-hover > tbody > tr > td.active:hover,
.table-hover > tbody > tr > th.active:hover,
.table-hover > tbody > tr.active:hover > td,
.table-hover > tbody > tr:hover > .active,
.table-hover > tbody > tr.active:hover > th {
 background-color: #e8e8e8;
}
.table > thead > tr > td.success,
.table > tbody > tr > td.success,
.table > tfoot > tr > td.success,
.table > thead > tr > th.success,
.table > tbody > tr > th.success,
.table > tfoot > tr > th.success,
.table > thead > tr.success > td,
.table > tbody > tr.success > td,
.table > tfoot > tr.success > td,
.table > thead > tr.success > th,
.table > tbody > tr.success > th,
.table > tfoot > tr.success > th {
 background-color: #dff0d8;
}
.table-hover > tbody > tr > td.success:hover,
.table-hover > tbody > tr > th.success:hover,
.table-hover > tbody > tr.success:hover > td,
.table-hover > tbody > tr:hover > .success,
.table-hover > tbody > tr.success:hover > th {
 background-color: #d0e9c6;
}
.table > thead > tr > td.info,
.table > tbody > tr > td.info,
.table > tfoot > tr > td.info,
.table > thead > tr > th.info,
.table > tbody > tr > th.info,
.table > tfoot > tr > th.info,
.table > thead > tr.info > td,
.table > tbody > tr.info > td,
.table > tfoot > tr.info > td,
.table > thead > tr.info > th,
.table > tbody > tr.info > th,
.table > tfoot > tr.info > th {
 background-color: #d9edf7;
}
.table-hover > tbody > tr > td.info:hover,
.table-hover > tbody > tr > th.info:hover,
.table-hover > tbody > tr.info:hover > td,
.table-hover > tbody > tr:hover > .info,
.table-hover > tbody > tr.info:hover > th {
 background-color: #c4e3f3;
}
.table > thead > tr > td.warning,
.table > tbody > tr > td.warning,
.table > tfoot > tr > td.warning,
.table > thead > tr > th.warning,
.table > tbody > tr > th.warning,
.table > tfoot > tr > th.warning,
.table > thead > tr.warning > td,
.table > tbody > tr.warning > td,
.table > tfoot > tr.warning > td,
.table > thead > tr.warning > th,
.table > tbody > tr.warning > th,
.table > tfoot > tr.warning > th {
 background-color: #fcf8e3;
}
.table-hover > tbody > tr > td.warning:hover,
.table-hover > tbody > tr > th.warning:hover,
.table-hover > tbody > tr.warning:hover > td,
.table-hover > tbody > tr:hover > .warning,
.table-hover > tbody > tr.warning:hover > th {
 background-color: #faf2cc;
}
.table > thead > tr > td.danger,
.table > tbody > tr > td.danger,
.table > tfoot > tr > td.danger,
.table > thead > tr > th.danger,
.table > tbody > tr > th.danger,
.table > tfoot > tr > th.danger,
.table > thead > tr.danger > td,
.table > tbody > tr.danger > td,
.table > tfoot > tr.danger > td,
.table > thead > tr.danger > th,
.table > tbody > tr.danger > th,
.table > tfoot > tr.danger > th {
 background-color: #f2dede;
}
.table-hover > tbody > tr > td.danger:hover,
.table-hover > tbody > tr > th.danger:hover,
.table-hover > tbody > tr.danger:hover > td,
.table-hover > tbody > tr:hover > .danger,
.table-hover > tbody > tr.danger:hover > th {
 background-color: #ebcccc;
}

<div class="table-responsive">
 <table class="table">
 </table>
</div>

//源码
.table-responsive {
 min-height: .01%;
 overflow-x: auto;
}
//把原有.table样式得底部外边距margin-bottom从20px改成了0px，目的是消除滚动条带来的上下高度差
//并在.table-responsive样式上设置了一个margin-bottom:15px,避免和容器外部的下一个元素重叠
@media screen and (max-width: 767px) {
 .table-responsive {
 width: 100%;
 margin-bottom: 15px;
 overflow-y: hidden;
 -ms-overflow-style: -ms-autohiding-scrollbar;
 border: 1px solid #ddd;
 }
 .table-responsive > .table {
 margin-bottom: 0;
 }
 .table-responsive > .table > thead > tr > th,
 .table-responsive > .table > tbody > tr > th,
 .table-responsive > .table > tfoot > tr > th,
 .table-responsive > .table > thead > tr > td,
 .table-responsive > .table > tbody > tr > td,
 .table-responsive > .table > tfoot > tr > td {
 white-space: nowrap;
 }
 .table-responsive > .table-bordered {
 border: 0;
 }
 //可以看到table-responsive给自己加了一个1px的外边框，如果在table上在使用table-bordered样式得话，就会和表格的外边框重合，就会变粗，所以进行了以下代码的编写
 .table-responsive > .table-bordered > thead > tr > th:first-child,
 .table-responsive > .table-bordered > tbody > tr > th:first-child,
 .table-responsive > .table-bordered > tfoot > tr > th:first-child,
 .table-responsive > .table-bordered > thead > tr > td:first-child,
 .table-responsive > .table-bordered > tbody > tr > td:first-child,
 .table-responsive > .table-bordered > tfoot > tr > td:first-child {
 border-left: 0;//所有tr的第一个单元格(最左边的一列)的左边框设置为0px
 }
 .table-responsive > .table-bordered > thead > tr > th:last-child,
 .table-responsive > .table-bordered > tbody > tr > th:last-child,
 .table-responsive > .table-bordered > tfoot > tr > th:last-child,
 .table-responsive > .table-bordered > thead > tr > td:last-child,
 .table-responsive > .table-bordered > tbody > tr > td:last-child,
 .table-responsive > .table-bordered > tfoot > tr > td:last-child {
 border-right: 0;//所有tr的最后一个单元格(最右边的一列)的左边框设置为0px
 }
 .table-responsive > .table-bordered > tbody > tr:last-child > th,
 .table-responsive > .table-bordered > tfoot > tr:last-child > th,
 .table-responsive > .table-bordered > tbody > tr:last-child > td,
 .table-responsive > .table-bordered > tfoot > tr:last-child > td {
 border-bottom: 0;//最后一行tr里的单元格的底部边框设置为0px
 }
}