@mixin placeholder {
  &.placeholder { @content }
  &:-ms-input-placeholder { @content }
  &:-moz-placeholder { @content }
  &::-moz-placeholder { @content }
  &::-webkit-input-placeholder { @content }
}

@mixin flex($grow: 1, $shrink: 1, $basis: auto) {
  -webkit-flex: $grow $shrink $basis;
  -moz-flex: $grow $shrink $basis;
  -ms-flex: $grow $shrink $basis;
  flex: $grow $shrink $basis;
}

@mixin flex-flow($values: (row wrap)) {
  -webkit-flex-flow: $values;
  -moz-flex-flow: $values;
  -ms-flex-flow: $values;
  flex-flow: $values;
}

@mixin justify-content($pos: center) {
  -webkit-justify-content: $pos;
  justify-content: $pos;
}

@mixin align-items($align: center) {
  -webkit-align-items: $align;
  align-items: $align;
}