title: CSS fade-in on page load, fade-out on hover
body: <p>Anybody know how to make a thumbnail fade in on page load and fade out to half opacity upon hover? </p>
  
  <p>I'm new to CSS transitions and animation. Many thanks in advance for your help! </p>
  
  <p>Here is my CSS for the fade-ins of the thumbnails:</p>
  
  <pre><code>/* make keyframes that tell the start state and the end state of our object */
  @-webkit-keyframes fadeIn { from { opacity:0; } to { opacity:1; } }
  @-moz-keyframes fadeIn { from { opacity:0; } to { opacity:1; } }
  @keyframes fadeIn { from { opacity:0; } to { opacity:1; } }
  
  .fade-in {
      opacity:0;  /* make things invisible upon start */
      -webkit-animation:fadeIn ease-in 1;  /* call our keyframe named fadeIn, use animattion ease-in and repeat it only 1 time */
      -moz-animation:fadeIn ease-in 1;
      animation:fadeIn ease-in 1;
  
      -webkit-animation-fill-mode:forwards;  /* this makes sure that after animation is done we remain at the last keyframe value (opacity: 1)*/
      -moz-animation-fill-mode:forwards;
      animation-fill-mode:forwards;
  
      -webkit-animation-duration:0.5s;
      -moz-animation-duration:0.5s;
      animation-duration:0.5s;
  }
  .fade-in.one {
  -webkit-animation-delay: 0.3s;
  -moz-animation-delay: 0.3s;
  animation-delay: 0.3s;
  }
  .fade-in.two {
  -webkit-animation-delay: 0.4s;
  -moz-animation-delay:0.4s;
  animation-delay: 0.4s;
  }
  .fade-in.three {
  -webkit-animation-delay: 0.5s;
  -moz-animation-delay: 0.5s;
  animation-delay: 0.5s;
  }
  .fade-in.four {
  -webkit-animation-delay: 0.6s;
  -moz-animation-delay: 0.6s;
  animation-delay: 0.6s;
  }
  .fade-in.five {
  -webkit-animation-delay: 0.7s;
  -moz-animation-delay: 0.7s;
  animation-delay: 0.7s;
  } 
  .fade-in.six {
  -webkit-animation-delay: 0.8s;
  -moz-animation-delay: 0.8s;
  animation-delay: 0.8s;
  }
  </code></pre>