<div class="bar">
   <span class="bar_content">
     Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s
   </span>
 </div>

@import url("https://fonts.googleapis.com/css?family=Gelasio&display=swap");

* { box-sizing: border-box; }

body,
html { overflow-x: hidden; }

.bar {
  position: absolute;
  top: 0;
  left: 0;

  width: 100%;
  padding: 25px 0;

  background-color: #e74c3c;
  color: white;

  font-family: Gelasio;
  font-size: 18px;
}

.bar_content {
  display: block; /* Important to give the content a width */

  width: 100%;
  transform: translateX(100%); /* Animation start out of the screen */

  /* Add the animation */
  animation: move 30s linear infinite /* infinite make reapeat the animation indefinitely */;
}

/* Create the animation */
@keyframes move {
  to { transform: translateX(-100%); }
}