【Liquid】theme.liquidのブロック要素追加

## ベタ書き

下記を追加して確認しました。
```theme.liquid
<!-- 雨のCSSアニメーション用 -->
  <div class="container">
  <div class="rains">
    <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>
  <p>テストストア</p>
  </div>
  ```

  ```rain.css
  /* 雨のアニメーション */
 .container{
  display:flex;
  justify-content: center;
  align-items: center;
  position:relative;
  width: 100%;
  height:200px;
  background: #0c0c33;
  overflow: hidden;
}
.container p{
  padding:20px;
  margin:0;
  font-size:40px;
  font-weight: bold;
  color:#FFF;
}
.rains{
  position: absolute;
  left:0;
  top:0;
  width: 100%;
  height:100%;
}

.rains span{
  position: absolute;
  width:3px;
  height:180px;
  background:#FFF;
  opacity:0.4;
}

.rains span:nth-child(1){left:5%; top:-190px; animation: rain-anim 10s infinite;}
.rains span:nth-child(2){left:10%; top:-180px; animation: rain-anim 11s infinite;}
.rains span:nth-child(3){left:15%; top:-170px; animation: rain-anim 8s infinite;}
.rains span:nth-child(4){left:20%; top:-160px; animation: rain-anim 12s infinite;}
.rains span:nth-child(5){left:25%; top:-150px; animation: rain-anim 10s infinite;}
.rains span:nth-child(6){left:30%; top:-150px; animation: rain-anim 11s infinite;}
.rains span:nth-child(7){left:35%; top:-160px; animation: rain-anim 13s infinite;}
.rains span:nth-child(8){left:40%; top:-170px; animation: rain-anim 7s infinite;}
.rains span:nth-child(9){left:45%; top:-180px; animation: rain-anim 9s infinite;}
.rains span:nth-child(10){left:50%; top:-190px; animation: rain-anim 11s infinite;}
.rains span:nth-child(11){left:55%; top:-190px; animation: rain-anim 10s infinite;}
.rains span:nth-child(12){left:60%; top:-180px; animation: rain-anim 6s infinite;}
.rains span:nth-child(13){left:65%; top:-170px; animation: rain-anim 14s infinite;}
.rains span:nth-child(14){left:70%; top:-160px; animation: rain-anim 12s infinite;}
.rains span:nth-child(15){left:75%; top:-150px; animation: rain-anim 10s infinite;}
.rains span:nth-child(16){left:80%; top:-150px; animation: rain-anim 14s infinite;}
.rains span:nth-child(17){left:85%; top:-160px; animation: rain-anim 8s infinite;}
.rains span:nth-child(18){left:90%; top:-170px; animation: rain-anim 9s infinite;}
.rains span:nth-child(19){left:95%; top:-180px; animation: rain-anim 11s infinite;}
.rains span:nth-child(20){left:100%; top:-190px; animation: rain-anim9 13s infinite;}

@keyframes rain-anim {
  0% { transform: translate(0px,0px);}
  4% { transform: translate(0px,600px);}
  5% { transform: translate(200px,0px);}
  9% { transform: translate(200px,600px);}
  10% { transform: translate(-100px,0px);}
  14% { transform: translate(-100px,600px);}
  15% { transform: translate(-200px,0px);}
  19% { transform: translate(-200px,600px);}
  20% { transform: translate(100px,0px);}
  24% { transform: translate(100px,600px);}
  25% { transform: translate(-150px,0px);}
  29% { transform: translate(-150px,600px);}
  30% { transform: translate(-80px,0px);}
  34% { transform: translate(-80px,600px);}
  35% { transform: translate(150px,0px);}
  39% { transform: translate(150px,600px);}
  40% { transform: translate(-60px,0px);}
  44% { transform: translate(-60px,600px);}
  45% { transform: translate(90px,0px);}
  49% { transform: translate(90px,600px);}
  50% { transform: translate(60px,0px);}
  54% { transform: translate(60px,600px);}
  55% { transform: translate(-60px,0px);}
  59% { transform: translate(-60px,600px);}
  60% { transform: translate(-40px,0px);}
  64% { transform: translate(-40px,600px);}
  65% { transform: translate(40px,0px);}
  69% { transform: translate(40px,600px);}
  70% { transform: translate(-20px,0px);}
  74% { transform: translate(-20px,600px);}
  75% { transform: translate(-110px,0px);}
  79% { transform: translate(-110px,600px);}
  80% { transform: translate(20px,0px);}
  84% { transform: translate(20px,600px);}
  85% { transform: translate(-20px,0px);}
  89% { transform: translate(-20px,600px);}
  90% { transform: translate(50px,0px);}
  99% { transform: translate(50px,600px);}
  100% { transform: translate(0px,0px);}
}
```


  ![Videotogif.gif](https://qiita-image-store.s3.ap-northeast-1.amazonaws.com/0/680582/10426c6d-d5ad-b193-79a1-ae42d452d910.gif)