滚动条默认样式修改自定义

          &::-webkit-scrollbar {
              width: 5px;
              background-color: #fff;
          }

          &::-webkit-scrollbar-track {
              background-color: transparent;
              -webkit-border-radius: 2px;
              -moz-border-radius: 2px;
              border-radius: 2px;
          }

          &::-webkit-scrollbar-track-piece {
              background-color: transparent;
              -webkit-border-radius: 2px;
              -moz-border-radius: 2px;
              border-radius: 2px;
          }

          &::-webkit-scrollbar-thumb {
              background-color: #B1B9CE;
              -webkit-border-radius: 2px;
              -moz-border-radius: 2px;
              border-radius: 2px;
          }