JSFiddle - React, Tailwind, and code Playground

by 苹果熊

HTML

<div class="bg">信封</div>

CSS

.bg {
  height: 20vh;
  padding: 1em;
  border: 1em solid transparent;
  background: linear-gradient(white, white) padding-box,
              repeating-linear-gradient(-45deg, red 0, red 12.5%, transparent 0, transparent 25%, green 0, green 37.5%, transparent 0, transparent 50%) 0 0 / 5em 5em;
  animation: ant 12s linear infinite;
}
@keyframes ant {
  to {
    background-position: 100%
  }
}