如何动画展开/收缩而不是向上/向下

Question

我试图让这条线表现得像一束阳光，沿对角线向下移动(↘)和向左向上移动(↖)。我得到的是up/down，尽管使用了高度降低。

在GIF中预览(使用图像编辑器创建)：

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body {
    background-color: grey;
}

.sunray {
    height: 200px; 
    width: 5px;
    background-color: white;
    opacity: 0.9; 
    filter: blur(5px);  
    transform: rotate(135deg); 
    position: relative;
    left: 60px;
    top: -50px;
} 
   
.sunray {
    animation: ray 1s linear infinite;
    animation-direction: alternate-reverse;
}
   
@keyframes ray {
    from { height: 200px; }
    to   { height: 50px; }
}

<div class="sunray"></div>

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Answer 1

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body {
  background-color: grey;
}

.container {
  height: 200px;
  width: 200px;
  overflow: hidden;
  outline: 1px solid black;
}

.sunray {
  height: 200px;
  width: 5px;
  background-color: white;
  opacity: 0.9;
  filter: blur(5px);
  position: relative;
  left: 60px;
  top: -50px;
}

.sunray {
  animation: ray 1s linear infinite;
  animation-direction: alternate-reverse;
}

@keyframes ray {
  from {
    transform: translate(-50px, -50px) rotate(-45deg);
  }
  to {
    transform: rotate(-45deg);
  }
}

<div class="container">
  <div class="sunray"></div>
</div>

​