(() => {
  const root = document.documentElement;
  const storageKey = "vapor_shell";
  const queryKey = "vapor_shell";
  const fallbackPreset = "miami-sunset";
  const allowed = new Set([
    "miami-sunset",
    "neon-grid",
    "laser-flamingo",
    "synth-lagoon",
    "mall-soft",
    "hologram-sky",
    "peach-drive",
    "ultraviolet-plaza",
    "cyber-mint",
  ]);

  const normalizePreset = (value) => {
    const trimmed = (value || "").trim().toLowerCase();
    if (!trimmed || !allowed.has(trimmed)) {
      return "";
    }
    return trimmed;
  };

  const setPreset = (value) => {
    const preset = normalizePreset(value);
    if (!preset) {
      return false;
    }
    root.setAttribute("data-vapor-shell", preset);
    return true;
  };

  root.classList.add("js");
  root.setAttribute("data-theme-mode", "auto");

  const url = new URL(window.location.href);
  const fromQuery = normalizePreset(url.searchParams.get(queryKey));
  if (fromQuery) {
    setPreset(fromQuery);
    try {
      window.localStorage.setItem(storageKey, fromQuery);
    } catch (_err) {
      // Keep behavior deterministic even when storage is blocked.
    }
    return;
  }

  const fromMarkup = normalizePreset(root.getAttribute("data-vapor-shell"));
  if (fromMarkup) {
    return;
  }

  try {
    const fromStorage = normalizePreset(window.localStorage.getItem(storageKey));
    if (fromStorage) {
      setPreset(fromStorage);
      return;
    }
  } catch (_err) {
    // Fallback handled below.
  }

  setPreset(fallbackPreset);
})();