Answers for "css animate opacity"

how to make animation stay on 100%

animation-fill-mode:forwards;

css opacity animation

<style>
.myelement{
  animation: fade-out;
}

@keyframes fade-out{
  0%{
    opacity: 1.0
  }
  100{
    opacity: 0.0
  }
}
</style>

opacity animation css

<style>
	.element-class {
		opacity: 0.5;
      	transition: opacity 0.5s ease-in-out;
	}
</style>