<div class="container">
  <div class="box">
  </div>
</div>

html,
body {
  height: 100vh;
  width: 100%;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  background: #00136c;
}

p {
  font-size: 24px;
  color: #fff;
}

.container {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.box {
  animation: loader 1.25s infinite;
  background-color: red;
  width: 50px;
  height: 50px;
  color: #00136c;
  display: flex;
  justify-content: center;
  align-items: center;
}

@keyframes loader {
  0% {
    rotate: 0deg;
  }
  100% {
    border-radius: 50%;
    rotate: 180deg;
  }
}