CSS3 实现的加载动画

<h1></h1>
<h3>JB51.net</h3>

<div class='loader loader1'>
  <div>
    <div>
      <div>
        <div>
          <div>
            <div></div>
          </div>
        </div>
      </div>
    </div>
  </div>
</div>

<div class='loader loader2'>
  <div>
    <div>
      <div>
        <div>
          <div>
            <div>
            </div>
          </div>
        </div>
      </div>
    </div>
  </div>
</div>

<div class='loader loader3'>
  <div>
    <div>
      <div>
        <div>
          <div>
            <div></div>
          </div>
        </div>
      </div>
    </div>
  </div>
</div>

<div class='loader loader4'>
  <div>
    <div>
      <div>
        <div>
          <div>
            <div>
              <div>
                <div>
                  <div>
                    <div></div>
                  </div>
                </div>
              </div>
            </div>
          </div>
        </div>
      </div>
    </div>
  </div>
</div>

@-webkit-keyframes rotate {
  0% {
    -webkit-transform: rotate(0deg);
            transform: rotate(0deg);
  }
  50% {
    -webkit-transform: rotate(180deg);
            transform: rotate(180deg);
  }
  100% {
    -webkit-transform: rotate(360deg);
            transform: rotate(360deg);
  }
}
@keyframes rotate {
  0% {
    -webkit-transform: rotate(0deg);
            transform: rotate(0deg);
  }
  50% {
    -webkit-transform: rotate(180deg);
            transform: rotate(180deg);
  }
  100% {
    -webkit-transform: rotate(360deg);
            transform: rotate(360deg);
  }
}
@-webkit-keyframes rotate2 {
  0% {
    -webkit-transform: rotate(0deg);
            transform: rotate(0deg);
    border-top-color: rgba(0, 0, 0, 0.5);
  }
  50% {
    -webkit-transform: rotate(180deg);
            transform: rotate(180deg);
    border-top-color: rgba(0, 0, 255, 0.5);
  }
  100% {
    -webkit-transform: rotate(360deg);
            transform: rotate(360deg);
    border-top-color: rgba(0, 0, 0, 0.5);
  }
}
@keyframes rotate2 {
  0% {
    -webkit-transform: rotate(0deg);
            transform: rotate(0deg);
    border-top-color: rgba(0, 0, 0, 0.5);
  }
  50% {
    -webkit-transform: rotate(180deg);
            transform: rotate(180deg);
    border-top-color: rgba(0, 0, 255, 0.5);
  }
  100% {
    -webkit-transform: rotate(360deg);
            transform: rotate(360deg);
    border-top-color: rgba(0, 0, 0, 0.5);
  }
}
* {
  box-sizing: border-box;
}

body {
  background: #f9f9f9;
  padding-bottom: 100px;
}

h1, h3 {
  display: block;
  margin: 0px auto;
  text-align: center;
  font-family: 'Tahoma';
  font-weight: lighter;
  color: rgba(0, 0, 0, 0.5);
  letter-spacing: 1.5px;
}

h1 {
  margin: 50px auto;
}

.loader {
  position: relative;
  margin: 75px auto;
  width: 150px;
  height: 150px;
  display: block;
  overflow: hidden;
}
.loader div {
  height: 100%;
}

/* loader 1 */
.loader1, .loader1 div {
  border-radius: 50%;
  padding: 8px;
  border: 2px solid transparent;
  -webkit-animation: rotate linear 3.5s infinite;
          animation: rotate linear 3.5s infinite;
  border-top-color: rgba(0, 0, 0, 0.5);
  border-bottom-color: rgba(0, 0, 255, 0.5);
}

/*loader 2  */
.loader2, .loader2 div {
  border-radius: 50%;
  padding: 8px;
  border: 2px solid transparent;
  -webkit-animation: rotate linear 3.5s infinite;
          animation: rotate linear 3.5s infinite;
  border-top-color: rgba(0, 0, 255, 0.5);
  border-left-color: rgba(0, 0, 0, 0.5);
  border-right-color: rgba(0, 0, 0, 0.5);
}

/*loader 3  */
.loader3, .loader3 div {
  border-radius: 50%;
  padding: 8px;
  border: 2px solid transparent;
  -webkit-animation: rotate linear 3.5s infinite;
          animation: rotate linear 3.5s infinite;
  border-top-color: rgba(0, 0, 0, 0.5);
  border-left-color: rgba(0, 0, 255, 0.5);
  -webkit-animation-timing-function: cubic-bezier(0.55, 0.38, 0.21, 0.88);
          animation-timing-function: cubic-bezier(0.55, 0.38, 0.21, 0.88);
  -webkit-animation-duration: 3s;
          animation-duration: 3s;
}

/* loader 4 */
.loader4, .loader4 div {
  border-radius: 50%;
  padding: 8px;
  border: 2px solid transparent;
  -webkit-animation: rotate linear 3.5s infinite;
          animation: rotate linear 3.5s infinite;
  border-radius: 50%;
  padding: 4px;
  -webkit-animation: rotate2 4s infinite linear;
          animation: rotate2 4s infinite linear;
}

div:hover {
  -webkit-animation-play-state: paused;
          animation-play-state: paused;
}

.loader, .loader * {
  will-change: transform;
}