body {
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 100vh;
  flex-direction: column;
}

.wrapper {
  width: 450px;
  height: 50px;
  position: relative;
  background: #ccc;
  overflow: hidden;
}

.wrapper::after {
  width: 448px;
  height: 48px;
  content: "";
  position: absolute;
  border: solid 1px white;
}

.box {
  width: 50px;
  height: 50px;
  position: absolute;
  background: red;
  font-size: 25px;
  line-height: 50px;
  text-align: center;
  color: var(--color-just-black);
}

.boxes {
  position: relative;
  left: -50px;
}

.nav {
  position: relative;
  text-align: center;

  color: white;
  font-size: 20px;
  margin: 20px 0;
}