/* 1. Reset & Base */
*, *::before, *::after {
    box-sizing: border-box;
    -webkit-tap-highlight-color: transparent;
  }
  
  :root {
    --bg:              #0d0e12;
    --surface:         #151619;
    --text-primary:    #e8e0d0;
    --text-muted:      #8a8070;
    --border:          rgba(255,255,255,0.07);
  
    /* Mode Accents */
    --accent-delta:    #6b4fa0;
    --accent-theta:    #5a3d8a;
    --accent-alpha:    #4a8c6a;
    --accent-beta:     #c2713a;
    --accent:          var(--accent-alpha);
  
    --radius-pill:     999px;
    --radius-card:     1.5rem;
    --transition-slow: 600ms cubic-bezier(0.25, 0.46, 0.45, 0.94);
    --transition-med:  350ms cubic-bezier(0.25, 0.46, 0.45, 0.94);
  }
  
  body {
    margin: 0;
    padding: 0;
    background: var(--bg);
    color: var(--text-primary);
    font-family: system-ui, -apple-system, sans-serif;
    font-size: clamp(14px, 1vw + 12px, 17px);
    line-height: 1.65;
    overflow: hidden; /* Prevent bounce scrolls */
    transition: background-color var(--transition-slow);
  }
  
  /* 2. Mode Switching Logic */
  body[data-mode="delta"] { --accent: var(--accent-delta); }
  body[data-mode="theta"] { --accent: var(--accent-theta); }
  body[data-mode="alpha"] { --accent: var(--accent-alpha); }
  body[data-mode="beta"]  { --accent: var(--accent-beta);  }
  
  /* 3. Canvas & App Shell */
  #main-canvas {
    position: fixed;
    inset: 0;
    z-index: 0;
  }
  
  #app {
    position: relative;
    z-index: 1;
    min-height: 100dvh;
    display: flex;
    flex-direction: column;
    padding: env(safe-area-inset-top) 1rem env(safe-area-inset-bottom);
  }
  
  /* 4. Header & Branding */
  #app-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1.5rem 0;
  }
  
  .logo {
    font-weight: 200;
    letter-spacing: 0.15em;
    text-transform: lowercase;
    font-size: 1.2rem;
  }
  
  /* 5. Components & UI */
  .glass {
    background: rgba(255, 255, 255, 0.05);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border: 1px solid var(--border);
    border-radius: var(--radius-card);
  }
  
  #start-prompt {
    position: fixed;
    inset: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--text-muted);
    font-weight: 300;
    pointer-events: none;
    transition: opacity var(--transition-slow);
  }
  
  /* 6. Mode Indicator (Bottom-Left) */
  .mode-badge {
    position: fixed;
    bottom: 1.5rem;
    left: 1.5rem;
    padding: 0.4rem 1rem;
    border-radius: var(--radius-pill);
    font-size: 0.8rem;
    letter-spacing: 0.05em;
    background: rgba(255, 255, 255, 0.03);
    border: 1px solid var(--border);
    color: var(--text-muted);
  }
  
  /* 7. Auth & Ghost Buttons */
  .btn-ghost {
    background: transparent;
    border: 1px solid var(--border);
    color: var(--text-muted);
    border-radius: var(--radius-pill);
    padding: 0.4rem 1.1rem;
    cursor: pointer;
    font-size: 0.85rem;
    letter-spacing: 0.04em;
    font-family: inherit;
    transition: border-color var(--transition-med), color var(--transition-med);
  }
  .btn-ghost:hover {
    border-color: var(--accent);
    color: var(--text-primary);
  }

  /* 8. Logo subtitle */
  .logo-sub {
    font-size: 0.75rem;
    font-weight: 300;
    color: var(--text-muted);
    letter-spacing: 0.08em;
    display: block;
    margin-top: 0.15rem;
  }

  /* 9. Start prompt sub-hint */
  .start-hint {
    display: block;
    font-size: 0.75rem;
    font-weight: 300;
    color: var(--text-muted);
    letter-spacing: 0.06em;
    margin-top: 0.5rem;
    opacity: 0.7;
  }

  /* 10. Utilities */
  .hidden {
    opacity: 0;
    pointer-events: none;
  }
  
  /* Hide scrollbars but keep functionality */
  * {
    scrollbar-width: none;
    -ms-overflow-style: none;
  }
  *::-webkit-scrollbar {
    display: none;
  }
  
  /* Accessible Focus */
  button:focus-visible, input:focus-visible {
    outline: 2px solid var(--accent);
    outline-offset: 4px;
  }
  
  /* Grain Animation Hook */
  #grain-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    pointer-events: none;
    z-index: 9999;
  }