[CSS] 모바일 스크롤바 항상 보이게 하기 (mobile scrollbar style with -webkit-scoll-)

::-webkit-scrollbar {
    width: 3px;
}
::-webkit-scrollbar-thumb {
    background: #a9a9a9;
}

[참고]

http://stackoverflow.com/questions/7492062/css-overflow-scroll-always-show-vertical-scroll-bar

https://css-tricks.com/examples/WebKitScrollbars/

http://circlash.tistory.com/610