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

:root {
  --bg-start: #0f1c2e; /* Midnight Blue */
  --bg-end: #050a10; /* Deep Navy/Black */
  --text-color: #e0e0e0;
  --text-muted: #8a8a8a;
  --font-main: "Merriweather", "Georgia", serif;
}

body {
  font-family: var(--font-main);
  background: linear-gradient(to bottom, var(--bg-start), var(--bg-end));
  color: var(--text-color);
  min-height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
  line-height: 1.8;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
}

/* Texture overlay (subtle noise) */
body::before {
  content: "";
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 200 200' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='noiseFilter'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.65' numOctaves='3' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23noiseFilter)' opacity='0.03'/%3E%3C/svg%3E");
  pointer-events: none;
  z-index: -1;
}

/* Layout */
.container {
  width: 90%;
  max-width: 600px;
  padding: 2rem;
  text-align: left; /* Keep text left aligned for readability or center if preferred, requirement says "Centered or gently vertically offset" - text alignment usually better left for paragraphs */
}

/* Typography & Animation */
.message {
  font-size: 1.125rem;
  font-weight: 300;
  opacity: 0;
  animation: fadeIn 2.5s ease-out forwards;
  animation-delay: 0.5s;
}

.message p {
  margin-bottom: 1.5rem;
}

@keyframes fadeIn {
  from {
    opacity: 0;
    transform: translateY(10px);
  } /* Subtle movement allowed? Req says "No movement-based animation" broadly, but "Only opacity-based fade-in". I will stick to PURE opacity as per "Only opacity-based fade-in". */
  to {
    opacity: 1;
  }
}

/* Strict check on animation: "Only opacity-based fade-in". Removing transform. */
/* Strict check on animation: "Only opacity-based fade-in". Removing transform. */
@keyframes fadeIn {
  from {
    opacity: 0;
  }
  to {
    opacity: 1;
  }
}

.signature {
  margin-top: 3rem;
  font-style: italic;
  font-size: 0.9em;
  opacity: 0.8;
}

/* Audio Toggle */
.audio-control {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  background: none;
  border: 1px solid var(--text-muted);
  color: var(--text-muted);
  padding: 0.5rem 1rem;
  font-family: sans-serif; /* Clean UI font */
  font-size: 0.8rem;
  border-radius: 20px;
  cursor: pointer;
  opacity: 0.5;
  transition: opacity 0.3s ease, border-color 0.3s ease, color 0.3s ease;
  z-index: 10;
}

.audio-control:hover,
.audio-control:focus {
  opacity: 1;
  border-color: var(--text-color);
  color: var(--text-color);
  outline: none;
}

/* Selection */
::selection {
  background: rgba(255, 255, 255, 0.1);
  color: #fff;
}

/* Responsive */
@media (max-width: 480px) {
  .message {
    font-size: 1rem;
  }
  .container {
    padding: 1.5rem;
  }
  .audio-control {
    bottom: 1.5rem;
    right: 1.5rem;
  }
}