/* ===== Reset & Base ===== */
*,
*::before,
*::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html,
body {
  width: 100%;
  height: 100%;
  overflow: hidden;
  font-family: 'Helvetica Neue', Arial, sans-serif;
}

body {
  background: linear-gradient(180deg,
      #c6e7f0 0%,
      #d4f0e0 30%,
      #f0e6f0 60%,
      #e8c8d8 100%);
  transition: background 0.05s;
}

/* ===== Strobe Classes ===== */
body.bg-a {
  background: hsl(var(--strobe-hue, 0), 100%, 50%) !important;
}

body.bg-b {
  background: #fff !important;
}

/* ===== Mute Button ===== */
.mute-btn {
  position: fixed;
  top: 15px;
  left: 20px;
  z-index: 200;
  font-size: 26px;
  cursor: pointer;
  opacity: 0.3;
  transition: opacity 0.2s ease;
  user-select: none;
}

.mute-btn:hover {
  opacity: 0.8;
}

.mute-btn.muted {
  opacity: 0.15;
  filter: grayscale(1);
}

/* ===== Canvas ===== */
#canvas {
  display: block;
  width: 100%;
  height: 100%;
  position: absolute;
  top: 0;
  left: 0;
}

/* ===== Splash Screen ===== */
#splash {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: 1000;
  background: rgba(0, 0, 0, 0.75);
  display: flex;
  align-items: center;
  justify-content: center;
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
}

.splash-box {
  background: rgba(20, 20, 30, 0.92);
  border: 1px solid rgba(255, 255, 255, 0.12);
  border-radius: 16px;
  padding: 48px 56px;
  max-width: 460px;
  text-align: center;
  color: #eee;
  box-shadow:
    0 25px 60px rgba(0, 0, 0, 0.5),
    0 0 80px rgba(100, 140, 200, 0.08);
}

.splash-box h1 {
  font-size: 28px;
  margin-bottom: 16px;
  font-weight: 700;
  letter-spacing: -0.5px;
}

.splash-box p {
  font-size: 15px;
  line-height: 1.6;
  color: #bbb;
  margin-bottom: 32px;
}

.splash-box p strong {
  color: #f77;
}

#accept {
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  color: #fff;
  border: none;
  padding: 14px 40px;
  border-radius: 10px;
  font-size: 16px;
  font-weight: 600;
  cursor: pointer;
  transition: transform 0.15s ease, box-shadow 0.15s ease;
  letter-spacing: 0.2px;
}

#accept:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 25px rgba(102, 126, 234, 0.45);
}

#accept:active {
  transform: translateY(0);
}

/* ===== Shake Hint ===== */
#shake {
  display: none;
  position: fixed;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  z-index: 100;
  color: rgba(0, 0, 0, 0.18);
  font-size: 22px;
  font-weight: 600;
  letter-spacing: 2px;
  text-transform: uppercase;
  pointer-events: none;
  animation: pulse 2.5s ease-in-out infinite;
}

@keyframes pulse {

  0%,
  100% {
    opacity: 0.3;
  }

  50% {
    opacity: 0.7;
  }
}

/* ===== Warning Label ===== */
#warning-label {
  position: fixed;
  bottom: 10px;
  left: 10px;
  z-index: 200;
  background: #000;
  color: #fff;
  font-size: 10px;
  padding: 6px 10px;
  line-height: 1.4;
  pointer-events: none;
  opacity: 0.6;
}