优化 table 在末行展开单元格后，出现的固定列水平未对其的问题

src/css/layui.css

@@ -1176,6 +1176,7 @@ select.layui-table-edit{padding: 0 0 0 10px; border-color: #d2d2d2;}
 .layui-table-cell-c{position: absolute; bottom: -10px; right: 50%; margin-right: -9px; width: 20px; height: 20px; line-height: 18px; cursor: pointer; text-align: center; background-color: #fff; border: 1px solid #eee; border-radius: 50%; z-index: 1000; transition: 0.3s all; font-size: 14px;}
 .layui-table-cell-c:hover{border-color: #16b777;}
 .layui-table-expanded td:hover .layui-table-cell{overflow: auto;}
+.layui-table-main > .layui-table > tbody > tr:last-child > td > .layui-table-cell-c{bottom: 0;}
 
 /* 单元格 TIPS 展开风格  */
 body .layui-table-tips .layui-layer-content{background: none; padding: 0; box-shadow: 0 1px 6px rgba(0,0,0,.12);}