html {
  height: 100%;
  width: 100%;
}

body {
  background-color: black;
  font-family: Arial, Helvetica, sans-serif;
}

p {
  text-decoration: none;
  color: whitesmoke;
}

a {
  text-decoration: none;
  color: greenyellow;
}

ul {
  list-style-type: none;
  margin: 0;
  padding: 0;
  width: 100%;
}

li a {
  display: block;
  color: #ffffff;
  padding: 0;
  text-decoration: none;
}

/* 鼠标移动到选项上修改背景颜色 */
li a:hover {
  background-color: #555;
  color: white;
}


.button1 {
  background-color: #4CAF50;
  /* Green */
  border: none;
  color: white;
  padding: 15px 32px;
  text-align: center;
  text-decoration: none;
  display: inline-block;
  font-size: 16px;
}

div {
  width: 10px;
  height: 10px;
  background: skyblue;
  animation: myanimation 3s;
  animation-iteration-count: infinite;
}

@keyframes myanimation {
  0% {
    background-color: red;
    width: 5px;
    height: 10px;
  }

  25% {
    background-color: yellow;
    width: 10px;
    height: 10px;
  }

  50% {
    background-color: blue;
    width: 10px;
    height: 5px;
  }

  75% {
    background-color: green;
    width: 10px;
    height: 10px;
  }

  100% {
    background-color: red;
    width: 5px;
    height: 10px;
  }
}

@-moz-keyframes myanimation {
  /* ... (same code as in the standard @keyframes) ... */
}

@-webkit-keyframes myanimation {
  /* ... (same code as in the standard @keyframes) ... */
}

@-o-keyframes myanimation {
  /* ... (same code as in the standard @keyframes) ... */
}