/* reset */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

/* full screen center */
body {
  height: 100vh;
  background: linear-gradient(135deg, #0f172a 0%, #1e293b 100%);
  font-family: system-ui, -apple-system, sans-serif;

  display: flex;
  align-items: center;
  justify-content: center;

  overflow: hidden;
  position: relative;
}

/* ambient background */
body::before {
  content: '';
  position: absolute;
  inset: 0;
  background: radial-gradient(
    circle at 30% 70%,
    rgba(59, 130, 246, 0.08),
    transparent 40%
  );
  pointer-events: none;
}

/* breathing glow */
body::after {
  content: '';
  position: absolute;
  inset: -50%;
  background: radial-gradient(
    circle at 50% 50%,
    rgba(255, 255, 255, 0.06),
    transparent 40%
  );
  animation: bg-wave 8s ease-in-out infinite;
  pointer-events: none;
}

/* text container */
.container {
  display: flex;
  align-items: center;
  justify-content: center;

  gap: 0.3rem;
  white-space: nowrap;
  flex-wrap: nowrap;

  z-index: 1;
}

/* letters */
.letter {
  /* 🔥 확 줄인 값 */
  font-size: clamp(1.4rem, 4.5vw, 5.5rem);

  font-weight: 800;
  color: #60a5fa;

  text-shadow:
    0 0 18px rgba(96, 165, 250, 0.7),
    0 0 40px rgba(96, 165, 250, 0.3);

  display: inline-block;
  transform-origin: bottom center;
  animation: wave 3.8s ease-in-out infinite;
}

/* spacing */
.letter.space {
  animation: none;
  width: 0.5em;
}

/* wave delay */
.letter:nth-child(1)  { animation-delay: 0s; }
.letter:nth-child(2)  { animation-delay: 0.08s; }
.letter:nth-child(3)  { animation-delay: 0.16s; }
.letter:nth-child(5)  { animation-delay: 0.24s; }
.letter:nth-child(6)  { animation-delay: 0.32s; }
.letter:nth-child(7)  { animation-delay: 0.4s; }
.letter:nth-child(9)  { animation-delay: 0.48s; }
.letter:nth-child(10) { animation-delay: 0.56s; }
.letter:nth-child(11) { animation-delay: 0.64s; }
.letter:nth-child(12) { animation-delay: 0.72s; }
.letter:nth-child(13) { animation-delay: 0.8s; }
.letter:nth-child(14) { animation-delay: 0.88s; }
.letter:nth-child(15) { animation-delay: 0.96s; }

/* wave */
@keyframes wave {
  0%, 100% {
    transform: translateY(0) rotateX(0deg);
  }
  50% {
    transform: translateY(-10px) rotateX(10deg);
  }
}

/* background motion */
@keyframes bg-wave {
  0% {
    transform: translate(-10%, -10%) scale(1);
    opacity: 0.4;
  }
  50% {
    transform: translate(10%, 10%) scale(1.1);
    opacity: 0.6;
  }
  100% {
    transform: translate(-10%, -10%) scale(1);
    opacity: 0.4;
  }
}