visible/hidden css pattern

bulb.css

// bulb is invisible without power
.bulb,
.bulb-inline,
.bulb-inline-block {
  display: none;
}

// bulb is visible with power
.power .bulb { display: block; }
.power .bulb-inline { display: inline; }
.power .bulb-inline-block { display: inline-block; }

// darkness is visible without power, but is invisible with power
.power .darkness { display: none; }