css3实现跳动/呼吸效果

跳动效果：

body{
    background:#ccc;
    margin: 0;
    height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
}

.box{
    height: 50px;
    width: 50px;
    position: relative;
}
.box::before{
    content: '';
    height: 8px; width: 50px; background: #000; opacity: .2; border-radius: 50%;
    position: absolute;
    top: 67px;
    left: 0;
    animation: shadow .5s linear infinite;
}
.box::after{
    border-radius: 5px;
    background: #fff;
    animation: rotate .5s linear infinite;
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    width: 50px;
    height: 50px;
}
@keyframes shadow {
    0%, 100% {transform: scaleX(1);}
    50% {transform: scaleX(1.2);}
}

@keyframes rotate {
    0% {
    	transform: translateY(0) ;
 	}
    25% {
        transform: translateY(10px);
    }
    50% {
        transform: translateY(20px) scale(1.1, 0.9);

    }
    75% {
        ransform: translateY(10px) ;
    }
    100% {
        transform: translateY(0) ;
    }
}

呼吸效果：

.heart {
  animation: breathe .5s linear infinite;
}
@keyframes breathe {
  0%{ transform: scale(.97); }
  50%{ transform: scale(1.1); }
  100%{ transform: scale(.97); }
}