$designWidth : 720 !default;
$designHeight : 1280 !default;
$fontSize: calc(100vw / 3.6);
html {
  font-size: $fontSize;
}
@function px2vw($px) {
  @return ($px / $designWidth)*100vw;
}
@function px2vh($px) {
  @return ($px / $designHeight)*100vh;
}
@function px2rem($px) {
  @return $px / 100 * 1rem;
}