.appear[data-src], .appear[data-bkg], .appear [data-src], .appear [data-bkg] { opacity: 0; -webkit-transition: opacity 1s ease-in; -moz-transition: opacity 1s ease-in; transition: opacity 1s ease-in; } .appeared[data-src], .appeared[data-bkg], .appeared [data-src], .appeared [data-bkg] { opacity: 1; }