:root { --bg: #2b2f36; --bar: rgba(10, 14, 20, .85); --fg: #fff; }
* { box-sizing: border-box; }
html, body { margin: 0; height: 100%; background: var(--bg); color: var(--fg); font-family: system-ui, -apple-system, "Segoe UI", Roboto, sans-serif; }
.fb { position: relative; height: 100vh; display: flex; flex-direction: column; background: radial-gradient(circle at 50% 40%, #4a505a, var(--bg)); }
.fb__stage { flex: 1; display: flex; align-items: center; justify-content: center; padding: 24px 16px 84px; overflow: hidden; }
#fb-book { width: 100%; max-width: 1400px; }
.fb__loading { position: absolute; inset: 0; display: flex; flex-direction: column; align-items: center; justify-content: center; gap: 12px; z-index: 3; }
.fb__loading a { color: #9cc3ff; }
.fb__spinner { width: 44px; height: 44px; border: 3px solid rgba(255,255,255,.25); border-top-color: #fff; border-radius: 50%; animation: spin 1s linear infinite; }
@keyframes spin { to { transform: rotate(360deg); } }
.fb__bar { position: fixed; left: 50%; bottom: 16px; transform: translateX(-50%); display: flex; align-items: center; gap: 4px; background: var(--bar); padding: 6px 10px; border-radius: 999px; z-index: 4; }
.fb__bar button, .fb__bar a { background: none; border: 0; color: var(--fg); width: 40px; height: 40px; border-radius: 50%; display: inline-flex; align-items: center; justify-content: center; cursor: pointer; font-size: 16px; text-decoration: none; }
.fb__bar button:hover, .fb__bar a:hover { background: rgba(255,255,255,.12); }
#fb-count { min-width: 72px; text-align: center; font-size: 14px; font-variant-numeric: tabular-nums; }
.fb__sep { width: 1px; height: 22px; background: rgba(255,255,255,.2); margin: 0 6px; }