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CSS

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CSS preprocessors help make authoring CSS easier. All of them offer things like variables and mixins to provide convenient abstractions.

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CSS Base

About CSS Base

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JavaScript

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Babel includes JSX processing.

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HTML 

              
                <div class="circle-1"></div>
<div class="circle-2"></div>
<div class="circle-3"></div>
<div class="circle-4"></div>
<div class="circle-5"></div>
<div class="circle-6"></div>
<div class="circle-7"></div>
<div class="circle-8"></div>
<div class="circle-9"></div>
<div class="circle-10"></div>
<div class="circle-11"></div>
!

CSS 

              
                .circle-1 {
  width: 65px;
  display: grid;
  --mask: 
    radial-gradient(12px at left 15px top 50%, #0000 95%, #000),
    radial-gradient(12px at right 15px top 50%, #0000 95%, #000);
  -webkit-mask: var(--mask);
          mask: var(--mask);
  -webkit-mask-composite: source-in;
          mask-composite: intersect;
  animation: c1 1s infinite alternate;
}
.circle-1:before,
.circle-1:after {
  content: "";
  grid-area: 1/1;
  height: 30px;
  aspect-ratio: 1;
  background: #fff;
  border-radius: 50%;
}
.circle-1:after {
  margin-left: auto;
}
@keyframes c1 {
  to {
    width: 40px;
  }
}

.circle-2 {
  width: 100px;
  display: grid;
  background: radial-gradient(farthest-side, #fff 98%, #0000) center/30px 100%
    no-repeat;
  --mask: 
    radial-gradient(12px at left 15px top 50%, #0000 95%, #000),
    radial-gradient(12px at center, #0000 95%, #000),
    radial-gradient(12px at right 15px top 50%, #0000 95%, #000);
  -webkit-mask: var(--mask);
          mask: var(--mask);
  -webkit-mask-composite: source-in;
          mask-composite: intersect;
  animation: c2 1s infinite alternate;
}
.circle-2:before,
.circle-2:after {
  content: "";
  grid-area: 1/1;
  height: 30px;
  aspect-ratio: 1;
  background: #fff;
  border-radius: 50%;
}
.circle-2:after {
  margin-left: auto;
}
@keyframes c2 {
  to {
    width: 50px;
  }
}

.circle-3 {
  width: 65px;
  height: 30px;
  position: relative;
}
.circle-3:before {
  content: "";
  position: absolute;
  border-radius: 50px;
  box-shadow: 0 0 0 3px inset #fff;
  animation: c3 0.75s infinite alternate;
}
@keyframes c3 {
  0% {
    inset: 0 35px 0 0;
  }
  50% {
    inset: 0 0 0 0;
  }
  100% {
    inset: 0 0 0 35px;
  }
}

.circle-4 {
  width: 65px;
  aspect-ratio: 1;
  position: relative;
}
.circle-4:before,
.circle-4:after {
  content: "";
  position: absolute;
  border-radius: 50px;
  box-shadow: 0 0 0 3px inset #fff;
  animation: c4 2.5s infinite;
}
.circle-4:after {
  animation-delay: -1.25s;
}
@keyframes c4 {
  0% {
    inset: 0 35px 35px 0;
  }
  12.5% {
    inset: 0 35px 0 0;
  }
  25% {
    inset: 35px 35px 0 0;
  }
  37.5% {
    inset: 35px 0 0 0;
  }
  50% {
    inset: 35px 0 0 35px;
  }
  62.5% {
    inset: 0 0 0 35px;
  }
  75% {
    inset: 0 0 35px 35px;
  }
  87.5% {
    inset: 0 0 35px 0;
  }
  100% {
    inset: 0 35px 35px 0;
  }
}

.circle-5 {
  width: 65px;
  aspect-ratio: 1;
  position: relative;
}
.circle-5:before,
.circle-5:after {
  content: "";
  position: absolute;
  inset: 0 auto auto 0;
  aspect-ratio: 1;
  border-radius: 50px;
  box-shadow: 0 0 0 3px inset #fff;
  animation: c5 1s infinite linear alternate;
}
.circle-5:after {
  inset: auto 0 0 auto;
  animation-delay: -1s;
}
@keyframes c5 {
  0% {
    width: 20px;
  }
  100% {
    width: 50px;
  }
}

.circle-6 {
  width: 50px;
  aspect-ratio: 1;
  box-shadow: 0 0 0 3px #fff inset;
  border-radius: 50%;
  position: relative;
  animation: c6 1.5s linear infinite;
}
.circle-6:before {
  content: "";
  position: absolute;
  top: 100%;
  box-shadow: inherit;
  width: 25px;
  aspect-ratio: 1;
  border-radius: 50%;
}
@keyframes c6 {
  to {
    transform: rotate(360deg);
  }
}

.circle-7 {
  width: 50px;
  aspect-ratio: 1;
  box-shadow: 0 0 0 3px #fff inset;
  border-radius: 50%;
  position: relative;
}
.circle-7:before,
.circle-7:after {
  content: "";
  position: absolute;
  top: 5px;
  left: calc(50% - 12.5px);
  box-shadow: inherit;
  width: 25px;
  aspect-ratio: 1;
  border-radius: 50%;
  transform-origin: 50% calc(100% - 5px);
  animation: c7 1.5s linear infinite;
}
.circle-7:after {
  top: calc(100% + 2px);
  transform-origin: 50% -27px;
  animation-delay: -0.75s;
}
@keyframes c7 {
  to {
    transform: rotate(360deg);
  }
}

.circle-8 {
  width: 50px;
  aspect-ratio: 1;
  box-shadow: 0 0 0 3px #fff inset;
  border-radius: 50%;
  position: relative;
  animation: c8-0 1.5s linear infinite;
}
.circle-8:before {
  content: "";
  position: absolute;
  top: 50%;
  left: calc(100% + 2px);
  box-shadow: inherit;
  width: 25px;
  aspect-ratio: 1;
  border-radius: 50%;
  animation: c8-1 1.5s linear infinite;
}
@keyframes c8-1 {
  0% {
    transform-origin: -27px 50%;
    width: 20px;
    transform: translateY(-50%) rotate(0);
  }
  100% {
    transform-origin: -12px 50%;
    width: 50px;
    transform: translateY(-50%) rotate(180deg);
  }
}
@keyframes c8-0 {
  0% {
    width: 50px;
    transform: translate(0);
  }
  100% {
    width: 20px;
    transform: translate(37px);
  }
}

.circle-9 {
  width: 100px;
  height: 40px;
  --g1: radial-gradient(farthest-side,#0000 calc(95% - 3px),#fff calc(100% - 3px) 98%,#0000 101%) no-repeat;
  background: var(--g1), var(--g1), var(--g1);
  background-size: 30px 30px;
  animation: c9 1s infinite alternate;
}
@keyframes c9 {
  0% {
    background-position: 0 50%, 50% 50%, 100% 50%;
  }
  20% {
    background-position: 0 0, 50% 50%, 100% 50%;
  }
  40% {
    background-position: 0 100%, 50% 0, 100% 50%;
  }
  60% {
    background-position: 0 50%, 50% 100%, 100% 0;
  }
  80% {
    background-position: 0 50%, 50% 50%, 100% 100%;
  }
  100% {
    background-position: 0 50%, 50% 50%, 100% 50%;
  }
}

.circle-10 {
  width: 65px;
  aspect-ratio: 1;
  --g1: radial-gradient(farthest-side,#0000 calc(95% - 3px),#fff calc(100% - 3px) 98%,#0000 101%) no-repeat;
  background: var(--g1), var(--g1), var(--g1);
  background-size: 30px 30px;
  animation: c10 1.5s infinite;
}
@keyframes c10 {
  0% {
    background-position: 0 0, 0 100%, 100% 100%;
  }
  25% {
    background-position: 100% 0, 0 100%, 100% 100%;
  }
  50% {
    background-position: 100% 0, 0 0, 100% 100%;
  }
  75% {
    background-position: 100% 0, 0 0, 0 100%;
  }
  100% {
    background-position: 100% 100%, 0 0, 0 100%;
  }
}

.circle-11 {
  width: 50px;
  aspect-ratio: 1;
  box-shadow: 0 0 0 3px #fff inset;
  border-radius: 50%;
  position: relative;
  animation: c11 7s infinite;
}
.circle-11:before,
.circle-11:after {
  content: "";
  position: absolute;
  top: calc(100% + 3px);
  left: calc(50% - 12.5px);
  box-shadow: inherit;
  width: 25px;
  aspect-ratio: 1;
  border-radius: 50%;
  transform-origin: 50% -28px;
  animation: c11 1.5s infinite;
}
.circle-11:after {
  animation-delay: -0.75s;
}
@keyframes c11 {
  100% {
    transform: rotate(360deg);
  }
}
/**/
body {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  grid-auto-rows: 130px;
  place-items: center;
  background: #000;
}

* {
  box-sizing: border-box;
}
!

JS
!
999px

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