:root {
    color-scheme: light dark;
    --bg: #0b0c0f;
    --fg: #e7e9ee;
    --muted: #9aa3b2;
    --card: #12141a;
    --border: #1f2330;
    --accent: #2563eb;
    --accent-600: #1d4ed8;
  }
  
  * { box-sizing: border-box; }
  
  html, body {
    height: 100%;
    margin: 0;
    font-family: ui-sans-serif, system-ui, -apple-system, Segoe UI, Roboto, Helvetica, Arial, "Apple Color Emoji", "Segoe UI Emoji";
    background: var(--bg);
    color: var(--fg);
  }
  
  .vh-center {
    min-height: 100vh;
    display: grid;
    place-items: center;
    padding: 1rem;
  }
  
  .card {
    width: 100%;
    max-width: 640px;
    background: var(--card);
    border: 1px solid var(--border);
    border-radius: 16px;
    padding: 1.25rem;
    box-shadow: 0 10px 30px rgba(0,0,0,0.35);
  }
  
  h1 {
    margin: 0 0 0.5rem 0;
    font-size: clamp(1.35rem, 2.5vw, 1.75rem);
  }
  
  .lead {
    margin: 0 0 1rem 0;
    color: var(--muted);
  }
  
  .btn {
    appearance: none;
    border: none;
    background: var(--accent);
    color: white;
    padding: 0.8rem 1.1rem;
    border-radius: 10px;
    font-weight: 600;
    cursor: not-allowed;
    opacity: 0.85;
    width: 100%;
    transition: background 0.2s ease, transform 0.05s ease, opacity 0.2s ease;
  }
  
  .btn.enabled {
    cursor: pointer;
    opacity: 1;
  }
  
  .btn.enabled:hover {
    background: var(--accent-600);
  }
  
  .btn.enabled:active {
    transform: translateY(1px);
  }
  
  .player-container {
    width: min(100%, 560px);
    height: 64px;
    background: var(--accent);
    border: none;
    border-radius: 12px;
    overflow: hidden;
    box-shadow: 0 6px 18px rgba(0, 0, 0, 0.35);
    display: block;
    cursor: pointer;
    transition: background 0.2s ease, transform 0.05s ease, box-shadow 0.2s ease;
  }
  
  .player-container:hover {
    background: var(--accent-600);
    box-shadow: 0 8px 22px rgba(0, 0, 0, 0.4);
  }
  
  .player-container:active {
    transform: translateY(1px);
  }
  
  .player-container iframe {
    width: 100%;
    height: 100%;
    border: 0;
  }
  
  /* Ensure [hidden] works despite other display rules */
  [hidden] {
    display: none !important;
  }
  
  /* Small screens */
  @media (max-width: 420px) {
    .card { padding: 1rem; border-radius: 12px; }
  }
  
  /* Accessibility: respect reduced motion */
  @media (prefers-reduced-motion: reduce) {
    *, *::before, *::after {
      animation: none !important;
      transition: none !important;
      scroll-behavior: auto !important;
    }
  }