@mixin transition($transition...) {
  -webkit-transition: $transition;
       -o-transition: $transition;
          transition: $transition;
}

// Placeholder text
@mixin placeholder($color: $input-color-placeholder) {
  // Firefox
  &::-moz-placeholder {
    color: $color;
    opacity: 1; // Override Firefox's unusual default opacity; see https://github.com/twbs/bootstrap/pull/11526
  }
  &:-ms-input-placeholder { color: $color; } // Internet Explorer 10+
  &::-webkit-input-placeholder  { color: $color; } // Safari and Chrome
}

@mixin form-control-focus($color: $input-border-focus) {
  $color-rgba: rgba(red($color), green($color), blue($color), .6);
  &:focus {
    border-color: $color;
    outline: 0;
    box-shadow: inset 0 1px 1px rgba(0,0,0,.075), 0 0 8px $color-rgba;
  }
}