Infinite Marquee using just HTML and CSS.

HTML

<div class="marquee-horizontal2">
    <div class="track-horizontal2">
        <div class="marquee-text">Marquee</div>
        <div class="marquee-text">Marquee</div>
        <div class="marquee-text">Marquee</div>
        <div class="marquee-text">Marquee</div>
        <div class="marquee-text">Marquee</div>
        <div class="marquee-text">Marquee</div>
    </div>
</div>

CSS

.marquee-horizontal2 {
  display: flex;
  overflow: hidden;
  width: 100%;
  white-space: nowrap;
  justify-content: flex-start;
  -webkit-box-align: center;
  align-items: center;
}

.track-horizontal2 {
  position: relative;
  display: flex;
  justify-content: flex-start;
  align-items: center;
  white-space: nowrap;
  will-change: transform;
  animation: marquee-horizontal 20s linear infinite;
}

.marquee-text {
  -webkit-text-size-adjust: 100%;
  -webkit-box-direction: normal;
  white-space: nowrap;
  box-sizing: border-box;
  padding-right: 0.3em;
  padding-left: 0.3em;
  -webkit-box-flex: 0;
  flex: 0 0 auto;
  font-family: 'Helvetica', sans-serif;
  color: #1d4130;
  font-size: 6.25em;
  font-weight: 700;
  text-transform: uppercase;
}

@keyframes marquee-horizontal {
  from {
    transform: translateX(0);
  }

  to {
    transform: translateX(-50%);
  }
}