.marquee-container {
  width: 100%;
  overflow: hidden;
  white-space: nowrap;
  box-sizing: border-box;
}

.marquee-content {
  color: red;
  font-weight: bold;
  font-size: 20px;
  display: inline-block;
  animation: marquee 10s linear infinite;
}

@keyframes marquee {
  0%   { transform: translateX(100%); }
  100% { transform: translateX(-100%); }
}