<div class="scan">
  <div class="qrcode"></div>
  <h3>二维码扫描中...</h3>
  <div class="border"></div>
</div>

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: consolas;
}

body {
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
  background: #111;
}

.scan {
  position: relative;
  display: flex;
  flex-direction: column;
  align-items: center;
}

.scan .qrcode {
  position: relative;
  width: 400px;
  height: 400px;
  background: url(https://mankeung.github.io/docs/mk-data/w.jpg);
  background-size: 330px;
  background-position: center;
  background-repeat: no-repeat;
}

.scan .qrcode::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: url(https://mankeung.github.io/docs/mk-data/border.png);
  background-size: 400px;
  overflow: hidden;
  animation: animate 4s ease-in-out infinite;
}

@keyframes animate {

  0%,
  100% {
    height: 20px;
  }

  50% {
    height: calc(100% - 20px);
  }
}

.scan .qrcode::after {
  content: '';
  position: absolute;
  inset: 20px;
  width: calc(100% - 40px);
  height: 2px;
  background: #35fd5c;
  filter: drop-shadow(0 0 20px #35fd5c) drop-shadow(0 0 60px #35fd5c);
  animation: animate_line 4s ease-in-out infinite;
}

@keyframes animate_line {

  0%,
  100% {
    top: 20px;
  }

  50% {
    top: calc(100% - 20px);
  }
}

.border {
  position: absolute;
  inset: 0px;
  background: url(https://mankeung.github.io/docs/mk-data/border.png);
  background-size: 400px;
  background-repeat: no-repeat;
  animation: animate_text 0.5s linear infinite;
}

@keyframes animate_text {

  0%,
  100% {
    opacity: 0;
  }

  50% {
    opacity: 1;
  }
}

.scan h3 {
  text-transform: uppercase;
  font-size: 2em;
  letter-spacing: 2px;
  margin-top: 20px;
  color: #fff;
  filter: drop-shadow(0 0 20px #fff) drop-shadow(0 0 60px #fff);
  animation: animate_text 0.5s steps(1) infinite;
}