2.HTML+CSS制作一闪一闪亮晶晶的星星（stars）

效果地址：https://codepen.io/flyingliao/pen/NJxbdB?editors=1100

HTML code：

<div class="stars">
　　<span></span><span></span>
　　<span></span><span></span>
　　<span></span><span></span>
　　<span></span><span></span>
　　<span></span><span></span>
　　<span></span><span></span>
　　<span></span><span></span>
　　<span></span><span></span>
　　<span></span><span></span>
　　<span></span><span></span>
</div>

CSS code：

html,body{
　　margin: 0;
　　padding: 0;
}
body{
    height: 100vh;
    background-color: black;
}
.stars{
    position: relative;
    width: 100%;
    height: 100%;
}
.stars span{
    display: inline-block;
    position: absolute;
    width: 5px;
    height: 5px;
    background-color: white;
    transform: rotate(45deg);
    /* 使星星模糊一点 */
    opacity: 0.2;
    /* 动画名称 动画时间  速度  开始时间 次数 */
    animation: blinking 1s linear var(--d) infinite;
}
/* blinking : 闪烁 */
@keyframes blinking{
    0%,100%{
      opacity: 0.2;
    }
    50%{
      /* 星星大小放大 1.5倍 ，旋转45度成菱形 */
      transform: scale(1.5) rotate(45deg);
      opacity: 1;
    }
}
.stars span:nth-child(1){
    top: 10%;
    left: 10%;
    --d: 10s;
}
.stars span:nth-child(2){
    top: 20%;
    left: 20%;
    --d: 6s;
}
.stars span:nth-child(3){
    top: 30%;
    left: 30%;
    --d: 5s;
}
.stars span:nth-child(4){
    top: 10%;
    margin-left: 40%;
    --d: 4s;
}
.stars span:nth-child(5){
    top: 40%;
    left: 60%;
    --d: 7s;
}
.stars span:nth-child(6){
    top: 30%;
    left: 80%;
    --d: 9s;
}
.stars span:nth-child(7){
    top: 40%;
    left: 20%;
    --d: 8s;
}
.stars span:nth-child(8){
    top: 50%;
    left: 40%;
    --d: 15s;
}
.stars span:nth-child(9){
    top: 60%;
    left: 70%;
    --d: 14s;
}
.stars span:nth-child(10){
    top: 80%;
    left: 50%;
    --d: 11s;
}
.stars span:nth-child(11){
    top: 75%;
    left: 23%;
    --d: 20s;
}
.stars span:nth-child(12){
    top: 55%;
    left: 4%;
    --d: 24s;
}
.stars span:nth-child(13){
    top: 36%;
    left: 26%;
    --d: 8s;
}
.stars span:nth-child(14){
    top: 93%;
    left: 18%;
    --d: 3s;
}
.stars span:nth-child(15){
    top: 58%;
    left: 68%;
    --d: 2.6s;
}
.stars span:nth-child(16){
    top: 64%;
    left: 86%;
    --d: 1.5s;
}
.stars span:nth-child(17){
    top: 6%;
    left: 78%;
    --d: 3.5s;
}
.stars span:nth-child(18){
    top: 13%;
    left: 58%;
    --d: 6s;
}
.stars span:nth-child(19){
    top: 50%;
    left: 50%;
    --d: 8s;
}
.stars span:nth-child(20){
    top: 88%;
    left: 88%;
    --d: 7s;
}