CSS만 사용하여 투명한 배경으로 부드럽게 움직이는 원 그리기 효과를 만드는 방법은 무엇입니까?

<code class="css">body {
  background: repeating-linear-gradient(45deg, white 0px, lightblue 100px);
  height: 500px;
  background-size: 500px 500px;
  background-repeat: no-repeat;
}

#container {
  position: absolute;
  width: 400px;
  height: 400px;
  border: solid red 1px;
  animation: colors 4s infinite;
}

#halfclip {
  width: 50%;
  height: 100%;
  right: 0px;
  position: absolute;
  overflow: hidden;
  transform-origin: left center;
  animation: cliprotate 16s steps(2) infinite;
  -webkit-animation: cliprotate 16s steps(2) infinite;
}

.halfcircle {
  box-sizing: border-box;
  height: 100%;
  right: 0px;
  position: absolute;
  border: solid 25px transparent;
  border-top-color: blue;
  border-left-color: blue;
  border-radius: 50%;
}

#clipped {
  width: 200%;
  animation: rotate 8s linear infinite;
  -webkit-animation: rotate 8s linear infinite;
}

#fixed {
  width: 100%;
  transform: rotate(135deg);
  animation: showfixed 16s steps(2) infinite;
  -webkit-animation: showfixed 16s linear infinite;
}

@-webkit-keyframes cliprotate {
  0% { transform: rotate(0deg); }
  100% { transform: rotate(360deg); }
}

@keyframes cliprotate {
  0% { transform: rotate(0deg); }
  100% { transform: rotate(360deg); }
}

@-webkit-keyframes rotate {
  0% { transform: rotate(-45deg); }
  100% { transform: rotate(135deg); }
}

@keyframes rotate {
  0% { transform: rotate(-45deg); }
  100% { transform: rotate(135deg); }
}

@-webkit-keyframes showfixed {
  0% { opacity: 0; }
  49.9% { opacity: 0; }
  50% { opacity: 1; }
  100% { opacity: 1; }
}
</code>