.semicircle,
.semicircle div {
  /*  Adjust the size of the entire animation here.
      (Remove max size below to go above 300px.) */
  width: 40vw;
  height: 40vw;

  /* Adjust the speed or timing function of the animation here. */
  animation: 8s rotate infinite linear;

  /*  Max size set because slower machines
      tend to struggle with the nested animations. */
  max-width: 40px;
  max-height: 40px;

  background-repeat: no-repeat;
  border-radius: 50%;
  position: relative;
  overflow: hidden;
}

.semicircle div {
  position: absolute;
  top: 5%;
  left: 5%;
  width: 90%;
  height: 90%;
}

.semicircle:before,
.semicircle div:before {
  content: '';
  width: 100%;
  height: 50%;
  display: block;
  background: radial-gradient(transparent, transparent 65%, rgb(255, 255, 255, 0.5) 65%, rgb(255, 255, 255, 0.5));
  background-size: 100% 200%;
}

@keyframes rotate {
  to {
    transform: rotate(360deg);
  }
}

.navbar-dark .navbar-nav .nav-link {
  color: rgb(255, 255, 255, 0.7) !important;
}