@each $key, $value in $opacity {
  .u-opacity#{capitalize($key)} {
    opacity: $value;
  }
  .hover\:u-opacity#{capitalize($key)}:hover {
    @media (hover: hover) {
      opacity: $value;
    }
  }
}

.u-visibilityVisible {
  visibility: visible;
}

.u-visibilityHidden {
  visibility: hidden;
}