* {
  box-sizing: border-box;
}

html {
  color-scheme: dark;
}

body {
  margin: 0;
  background: #000;
  color: #fff;
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
}

main {
  min-height: 100dvh;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 32px 20px;
  text-align: center;
}

h1 {
  margin: 0 0 16px;
  font-size: clamp(2rem, 8vw, 3.5rem);
  line-height: 1.1;
}

.lead {
  max-width: 34rem;
  margin: 0 0 clamp(28px, 5vh, 44px);
  font-size: clamp(1rem, 3.2vw, 1.2rem);
  line-height: 1.6;
  color: rgb(255 255 255 / 0.85);
  text-wrap: balance;
}

.buttons {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: clamp(20px, 4vh, 32px);
}

/* Círculo básico: apagado por defecto; anillo y brillo suave mientras suena su audio */
.btn {
  --size: clamp(64px, 11vh, 88px);

  width: var(--size);
  height: var(--size);
  padding: 0;
  border: 0;
  border-radius: 50%;
  background: var(--tone);
  opacity: 0.6;
  cursor: pointer;
  transition: opacity 0.25s, transform 0.1s, box-shadow 0.25s;
  -webkit-tap-highlight-color: transparent;
}

@media (hover: hover) {
  .btn:hover {
    opacity: 0.8;
  }
}

.btn:active {
  transform: scale(0.94);
}

.btn:focus-visible {
  outline: 2px solid #fff;
  outline-offset: 6px;
}

.btn.is-active {
  opacity: 1;
  box-shadow: 0 0 0 5px #000, 0 0 0 7px var(--tone), 0 0 36px 6px var(--glow);
  animation: breathe 1.8s ease-in-out infinite;
}

@keyframes breathe {
  50% {
    transform: scale(1.05);
  }
}

.btn--rose {
  --tone: #c47a8a;
  --glow: rgb(196 122 138 / 0.35);
}

.btn--sand {
  --tone: #c9ab74;
  --glow: rgb(201 171 116 / 0.35);
}

.btn--blue {
  --tone: #7490c4;
  --glow: rgb(116 144 196 / 0.35);
}

@media (prefers-reduced-motion: reduce) {
  .btn {
    transition: none;
  }

  .btn.is-active {
    animation: none;
  }
}