html, body {
  margin: 0;
  overflow: hidden;
}

.stage {
  box-sizing: border-box;
  min-height: 100vh;
  display: grid;
  place-items: center;
  margin: 0;
  background: #ff4d1f;
  font-family: -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  padding: clamp(8px, 4vw, 24px);
}

.fv7 {
  width: min(240px, 86vw);
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.fv7__input {
  box-sizing: border-box;
  width: 100%;
  padding: 8px 12px;
  border-radius: 8px;
  border: 2px solid #fff7e6;
  background: rgba(255, 255, 255, 0.14);
  color: #fff7e6;
  font-weight: 400;
  font-size: 14px;
  line-height: 1;
  font-family: inherit;
}

.fv7__track {
  position: relative;
  height: 6px;
  border-radius: 4px;
  background: rgba(255, 255, 255, 0.25);
  overflow: hidden;
}

.fv7__fill {
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: 100%;
  border-radius: 4px;
  transform-origin: left center;
  transform: scaleX(0);
  opacity: 0;
}

.fv7__fill--weak {
  background: #ffe0d8;
}

.fv7__fill--mid {
  background: #ffd23f;
}

.fv7__fill--strong {
  background: #4cd4a6;
}

.fv7__track::after {
  content: "";
  position: absolute;
  left: 0;
  top: -3px;
  bottom: -3px;
  width: 100%;
  border-radius: 4px;
  opacity: 0;
  pointer-events: none;
}

@keyframes fv7-weak {
  0%, 6% {
    transform: scaleX(0);
    opacity: 0;
  }
  14%, 30% {
    transform: scaleX(0.32);
    opacity: 1;
  }
  36%, 100% {
    opacity: 0;
  }
}
@keyframes fv7-mid {
  0%, 36% {
    transform: scaleX(0.32);
    opacity: 0;
  }
  44%, 62% {
    transform: scaleX(0.64);
    opacity: 1;
  }
  68%, 100% {
    opacity: 0;
  }
}
@keyframes fv7-strong {
  0%, 68% {
    transform: scaleX(0.64);
    opacity: 0;
  }
  78%, 96% {
    transform: scaleX(1);
    opacity: 1;
  }
  100% {
    opacity: 0;
    transform: scaleX(0);
  }
}
@keyframes fv7-track-pulse {
  0%, 13% {
    transform: scaleY(1);
  }
  14% {
    transform: scaleY(1.15);
  }
  17% {
    transform: scaleY(0.95);
  }
  20% {
    transform: scaleY(1.03);
  }
  23% {
    transform: scaleY(1);
  }
  43% {
    transform: scaleY(1);
  }
  44% {
    transform: scaleY(1.15);
  }
  47% {
    transform: scaleY(0.95);
  }
  50% {
    transform: scaleY(1.03);
  }
  53% {
    transform: scaleY(1);
  }
  77% {
    transform: scaleY(1);
  }
  78% {
    transform: scaleY(1.15);
  }
  81% {
    transform: scaleY(0.95);
  }
  84% {
    transform: scaleY(1.03);
  }
  87% {
    transform: scaleY(1);
  }
  100% {
    transform: scaleY(1);
  }
}
@keyframes fv7-surge {
  0%, 12% {
    opacity: 0;
    box-shadow: 0 0 0 0 rgba(255, 224, 216, 0);
  }
  14% {
    opacity: 0.9;
    box-shadow: 0 0 0 4px rgba(255, 224, 216, 0.55);
  }
  22% {
    opacity: 0;
    box-shadow: 0 0 0 9px rgba(255, 224, 216, 0);
  }
  42% {
    opacity: 0;
    box-shadow: 0 0 0 0 rgba(255, 210, 63, 0);
  }
  44% {
    opacity: 0.9;
    box-shadow: 0 0 0 4px rgba(255, 210, 63, 0.55);
  }
  52% {
    opacity: 0;
    box-shadow: 0 0 0 9px rgba(255, 210, 63, 0);
  }
  76% {
    opacity: 0;
    box-shadow: 0 0 0 0 rgba(76, 212, 166, 0);
  }
  78% {
    opacity: 0.9;
    box-shadow: 0 0 0 4px rgba(76, 212, 166, 0.55);
  }
  86% {
    opacity: 0;
    box-shadow: 0 0 0 9px rgba(76, 212, 166, 0);
  }
  100% {
    opacity: 0;
    box-shadow: 0 0 0 0 rgba(255, 224, 216, 0);
  }
}
.fv7.is-demo .fv7__fill--weak {
  animation: fv7-weak 2s cubic-bezier(0.2, 0.8, 0.2, 1) infinite;
}

.fv7.is-demo .fv7__fill--mid {
  animation: fv7-mid 2s cubic-bezier(0.2, 0.8, 0.2, 1) infinite;
}

.fv7.is-demo .fv7__fill--strong {
  animation: fv7-strong 2s cubic-bezier(0.2, 0.8, 0.2, 1) infinite;
}

.fv7.is-demo .fv7__track {
  animation: fv7-track-pulse 2s cubic-bezier(0.2, 0.8, 0.2, 1) infinite;
}

.fv7.is-demo .fv7__track::after {
  animation: fv7-surge 2s cubic-bezier(0.2, 0.8, 0.2, 1) infinite;
}

@media (prefers-reduced-motion: reduce) {
  .fv7.is-demo .fv7__fill {
    animation: none !important;
    opacity: 0;
  }
  .fv7.is-demo .fv7__fill--strong {
    opacity: 1;
    transform: scaleX(1);
  }
  .fv7.is-demo .fv7__track,
  .fv7.is-demo .fv7__track::after {
    animation: none !important;
  }
  .fv7.is-demo .fv7__track::after {
    opacity: 0;
  }
}