.os-fab {
  position: fixed;
  right: 18px;
  bottom: 18px;
  z-index: 99999;
  display: flex;
  flex-direction: column;
  gap: 10px;
  align-items: flex-end;
  pointer-events: none;
}

.os-fab__btn {
  pointer-events: auto;
  border: 0;
  cursor: pointer;
  padding: 12px 14px;
  border-radius: 999px;
  display: inline-flex;
  align-items: center;
  gap: 10px;

  color: #eaf6ff;
  font-weight: 800;
  font-size: 14px;
  letter-spacing: 0.01em;

  background: linear-gradient(135deg, rgba(59,130,246,.95), rgba(34,197,94,.85));
  box-shadow: 0 18px 45px rgba(0,0,0,.45), 0 0 0 1px rgba(255,255,255,.12) inset;
  backdrop-filter: blur(8px);

  transform: translateY(0);
  transition: transform .18s ease, filter .18s ease, box-shadow .18s ease, opacity .18s ease;
}

.os-fab__btn:hover {
  transform: translateY(-2px);
  filter: brightness(1.05);
  box-shadow: 0 22px 55px rgba(0,0,0,.55), 0 0 0 1px rgba(255,255,255,.18) inset;
}

.os-fab__icon {
  width: 30px;
  height: 30px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border-radius: 999px;
  background: rgba(2, 6, 23, 0.35);
  box-shadow: 0 0 0 1px rgba(255,255,255,.14) inset;
}

.os-fab__hint {
  pointer-events: none;
  max-width: 340px;
  padding: 10px 12px;
  border-radius: 14px;
  color: #cfe7ff;
  font-size: 12px;
  line-height: 1.35;
  background: rgba(2, 6, 23, 0.72);
  border: 1px solid rgba(148, 163, 184, 0.25);
  box-shadow: 0 16px 40px rgba(0,0,0,.35);
  display: none;
}

.os-fab--hidden { display: none; }
.os-fab__btn[disabled] { cursor: not-allowed; }