以下为HTML代码，非常简单，只需一行

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

以下为部分CSS代码

.container::before {
  content: "";
  position: absolute;
  inset: -145%;
  rotate: -45deg;
  background: #000;
  background-image: radial-gradient(4px 100px at 0px 235px, #0f0, #0000),
    radial-gradient(4px 100px at 300px 235px, #0f0, #0000),
    radial-gradient(1.5px 1.5px at 150px 117.5px, #0f0 100%, #0000 150%),