CSS 중앙정렬

.race-by {
    --uib-size: 80px;
    --uib-speed: 1.4s;
    --uib-color: black;
    --uib-line-weight: 5px;
  
    position: relative;
    display: flex;
    align-items: center;
    justify-content: center;
    height: var(--uib-line-weight);
    width: var(--uib-size);
    border-radius: calc(var(--uib-line-weight) / 2);
    overflow: hidden;
    transform: translate3d(0, 0, 0);
  }
  
  .race-by::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    height: 100%;
    width: 100%;
    background-color: var(--uib-color);
    opacity: 0.1;
  }
  
  .race-by::after {
    content: '';
    height: 100%;
    width: 100%;
    border-radius: calc(var(--uib-line-weight) / 2);
    animation: raceBy var(--uib-speed) ease-in-out infinite;
    transform: translateX(-100%);
    background-color: var(--uib-color);
  }
  
  @keyframes raceBy {
    0% {
      transform: translateX(-100%);
    }
    100% {
      transform: translateX(100%);
    }
  }