css设置正方形动态背景

.wrapper {
    background: #50a3a2;
    background: -webkit-linear-gradient(top left, #50a3a2 0%, #53e3a6 100%);
    background: linear-gradient(to bottom right, #127c7b 0, #50a3a2);
    opacity: 0.8;
    position: absolute;
    left: 0;
    width: 100%;
    height: 100%;
    overflow: hidden;
}

.wrapper.form-success .containerLogin h1 {
    -webkit-transform: translateY(85px);
    -ms-transform: translateY(85px);
    transform: translateY(85px);
}

.bg-bubbles {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: 1;
}

.bg-bubbles li, .bg-bubbles ol {
    position: absolute;
    list-style: none;
    display: block;
    width: 40px;
    height: 40px;
    background-color: rgba(255, 0, 0, 0.15);
    bottom: -160px;
    -webkit-animation: square 25s infinite;
    animation: square 25s infinite;
    -webkit-transition-timing-function: linear;
    transition-timing-function: linear;
}

ol {
    padding: 0 !important;
}

.bg-bubbles ol:nth-child(11) {
    left: 10%;
    top: 10%;
    width: 20px;
    height: 20px;
}

.bg-bubbles ol:nth-child(12) {
    left: 20%;
    top: 40%;

    width: 60px;
    height: 60px;
}

.bg-bubbles ol:nth-child(13) {
    left: 65%;
    top: 30%;

    width: 100px;
    height: 60px;
}

.bg-bubbles ol:nth-child(14) {
    left: 70%;
    top: 30%;
    width: 100px;
    height: 150px;
}

.bg-bubbles ol:nth-child(15) {
    left: 50%;
    top: 70%;

    width: 40px;
    height: 60px;
}

.bg-bubbles li:nth-child(1) {
    left: 10%;
}

.bg-bubbles li:nth-child(2) {
    left: 20%;
    width: 80px;
    height: 80px;
    -webkit-animation-delay: 2s;
    animation-delay: 2s;
    -webkit-animation-duration: 17s;
    animation-duration: 17s;
}

.bg-bubbles li:nth-child(3) {
    left: 25%;
    -webkit-animation-delay: 4s;
    animation-delay: 4s;
}

.bg-bubbles li:nth-child(4) {
    left: 40%;
    width: 60px;
    height: 60px;
    -webkit-animation-duration: 22s;
    animation-duration: 22s;
    background-color: rgba(255, 0, 255, 0.25);
}

.bg-bubbles li:nth-child(5) {
    left: 70%;
}

.bg-bubbles li:nth-child(6) {
    left: 80%;
    width: 120px;
    height: 120px;
    -webkit-animation-delay: 3s;
    animation-delay: 3s;
    background-color: rgba(255, 255, 0, 0.2);
}

.bg-bubbles li:nth-child(7) {
    left: 32%;
    width: 160px;
    height: 160px;
    -webkit-animation-delay: 7s;
    animation-delay: 7s;
}

.bg-bubbles li:nth-child(8) {
    left: 55%;
    width: 20px;
    height: 20px;
    -webkit-animation-delay: 15s;
    animation-delay: 15s;
    -webkit-animation-duration: 40s;
    animation-duration: 40s;
}

.bg-bubbles li:nth-child(9) {
    left: 25%;
    width: 10px;
    height: 10px;
    -webkit-animation-delay: 2s;
    animation-delay: 2s;
    -webkit-animation-duration: 40s;
    animation-duration: 40s;
    background-color: rgba(255, 255, 0, 0.3);
}

.bg-bubbles li:nth-child(10) {
    left: 90%;
    width: 160px;
    height: 160px;
    -webkit-animation-delay: 11s;
    animation-delay: 11s;
}

@-webkit-keyframes square {
    0% {
        -webkit-transform: translateY(0);
        transform: translateY(0);
    }

    100% {
        -webkit-transform: translateY(-700px) rotate(600deg);
        transform: translateY(-700px) rotate(600deg);
    }
}

@keyframes square {
    0% {
        -webkit-transform: translateY(0);
        transform: translateY(0);
    }

    100% {
        -webkit-transform: translateY(-700px) rotate(600deg);
        transform: translateY(-700px) rotate(600deg);
    }
}

      <div className='wrapper'>
        <ul class="bg-bubbles">
          <li v-for="n in 10" :key="n+'n'"></li>
          <ol v-for="m in 5"  :key="m+'m'"></ol>
        </ul>
      </div >