body { margin: 20px; }

.marquee {
  height: 25px;
  width: 420px;
  overflow: hidden;
  position: relative;
  align-items: center;
  justify-content: center;
  white-space: nowrap;
}

.marquee div {
  display: block;
  width: 6076px;
  height: 30px;

  position: absolute;
  overflow: hidden;

  animation: marquee 15s linear infinite;
}

.marquee span {
  float: left;
  width: 50%;
}

@keyframes marquee {
  0% { left: 0; }
  100% { left: -4500px; }
}