:root {
  --pointer-x: 50%;
  --pointer-y: 50%;
  --accent-hue: 220;
  --button-scale: 1;
  --accent: hsl(var(--accent-hue), 70%, 48%);
  --bg: #f3f1ec;
  --panel: #fbfaf7;
  --text: #111111;
  --muted: #666666;
  --line: #1a1a1a;
  --soft-line: #d9d5cd;
}

* {
  box-sizing: border-box;
}

body {
  min-height: 100vh;
  margin: 0;
  display: grid;
  place-items: center;
  font-family: Arial, Helvetica, sans-serif;
  color: var(--text);
  background: var(--bg);
}

.app-shell {
  width: min(92vw, 780px);
  padding: 2.25rem 1.25rem;
}

.page-note {
  margin: 0 0 0.75rem;
  font-size: 0.82rem;
  letter-spacing: 0.03em;
  color: var(--muted);
}

h1 {
  margin: 0 0 1rem;
  font-size: clamp(2rem, 4vw, 2.8rem);
  font-weight: 700;
  letter-spacing: -0.03em;
}

.instrument-panel {
  position: relative;
  display: grid;
  place-items: center;
  min-height: 520px;
  padding: 2rem;
  border: 1px solid var(--line);
  background: var(--panel);
  overflow: hidden;
}

.instrument-panel::before {
  content: "";
  position: absolute;
  inset: 18px;
  border: 1px solid var(--soft-line);
  pointer-events: none;
}

.instrument-panel::after {
  content: "";
  position: absolute;
  left: 0;
  top: 0;
  width: 100%;
  height: 6px;
  background: linear-gradient(
    90deg,
    transparent 0,
    transparent calc(var(--pointer-x) - 10%),
    var(--accent) calc(var(--pointer-x) - 10%),
    var(--accent) calc(var(--pointer-x) + 10%),
    transparent calc(var(--pointer-x) + 10%),
    transparent 100%
  );
  opacity: 0.9;
  pointer-events: none;
}

.ambient-glow {
  position: absolute;
  width: 14px;
  height: 14px;
  border: 2px solid var(--accent);
  background: transparent;
  left: calc(var(--pointer-x) - 7px);
  top: calc(var(--pointer-y) - 7px);
  pointer-events: none;
  transition: left 90ms linear, top 90ms linear, border-color 120ms linear;
}

.status-bar {
  position: absolute;
  top: 1rem;
  left: 1rem;
  right: 1rem;
  display: flex;
  justify-content: space-between;
  gap: 0.75rem;
  flex-wrap: wrap;
  z-index: 2;
}

.status-bar p {
  margin: 0;
  padding: 0.55rem 0.75rem;
  border: 1px solid var(--line);
  background: #ffffff;
  font-size: 0.88rem;
}

.label {
  color: var(--muted);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin-right: 0.35rem;
  font-size: 0.72rem;
}

.sound-button {
  position: relative;
  width: min(56vw, 260px);
  min-height: 74px;
  padding: 1rem 1.25rem;
  border: 1px solid var(--line);
  background: #ffffff;
  color: var(--text);
  font-size: clamp(1rem, 2vw, 1.2rem);
  font-weight: 700;
  letter-spacing: 0.02em;
  cursor: pointer;
  transform: scale(var(--button-scale));
  transition: transform 120ms ease, background 120ms ease, color 120ms ease, outline-offset 120ms ease;
  z-index: 2;
}

.sound-button:hover {
  background: #f1efe8;
}

.sound-button:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 4px;
}

.sound-button:active,
.sound-button.is-pressed {
  --button-scale: 0.98;
  background: var(--text);
  color: #ffffff;
}

.button-core {
  position: relative;
  z-index: 2;
}

.button-ring {
  position: absolute;
  inset: -10px;
  border: 1px solid var(--accent);
  pointer-events: none;
  opacity: 0;
}

.sound-button.is-armed .button-ring-one,
.sound-button.is-pressed .button-ring-one {
  animation: ringPulse 1.1s linear infinite;
}

.sound-button.is-pressed .button-ring-two {
  animation: ringPulse 1.1s linear 0.2s infinite;
}

.instructions {
  position: absolute;
  bottom: 1.25rem;
  margin: 0;
  max-width: 560px;
  padding: 0 1rem;
  text-align: center;
  line-height: 1.5;
  font-size: 0.92rem;
  color: var(--muted);
  z-index: 2;
}

body.mode-echo .instrument-panel {
  border-color: var(--accent);
}

body.mode-echo .status-bar p {
  border-color: var(--accent);
}

@keyframes ringPulse {
  0% {
    transform: scale(1);
    opacity: 0.6;
  }
  100% {
    transform: scale(1.12);
    opacity: 0;
  }
}

@media (max-width: 640px) {
  .app-shell {
    width: min(94vw, 780px);
    padding: 1.25rem 0.75rem 2rem;
  }

  .instrument-panel {
    min-height: 500px;
    padding: 1.5rem 1rem 4.75rem;
  }

  .status-bar {
    justify-content: flex-start;
  }

  .status-bar p {
    font-size: 0.84rem;
  }

  .sound-button {
    width: min(72vw, 260px);
  }
}