diff --git a/npm/scripts/postinstall.js b/npm/scripts/postinstall.js
index ff1ad06..da4a2f3 100644
--- a/npm/scripts/postinstall.js
+++ b/npm/scripts/postinstall.js
@@ -1,6 +1,8 @@
 const { spawnSync } = require("node:child_process");
 const fs = require("node:fs");
 const path = require("node:path");
+const https = require("node:https");
+const os = require("node:os");
 
 const packageRoot = path.resolve(__dirname, "..", "..");
 const venvDir = path.join(packageRoot, ".smart-search-python");
@@ -16,7 +18,7 @@ function run(command, args, options = {}) {
   if (result.error) {
     return { ok: false, error: result.error };
   }
-  return { ok: result.status === 0, status: result.status, stdout: result.stdout || "" };
+  return { ok: result.status === 0, status: result.status, stdout: result.stdout || "", stderr: result.stderr || "" };
 }
 
 function pythonCandidates() {
@@ -54,34 +56,192 @@ function venvPython() {
     : path.join(venvDir, "bin", "python");
 }
 
-const python = findPython();
-if (!python) {
-  console.error("smart-search requires Python 3.10 or newer.");
-  console.error("Install Python, then run: npm install -g @konbakuyomu/smart-search@latest");
-  process.exit(1);
+/**
+ * Download a URL to a temporary file and return the file path.
+ */
+function downloadToTempFile(url) {
+  return new Promise((resolve, reject) => {
+    const tmpFile = path.join(os.tmpdir(), `smart-search-get-pip-${Date.now()}.py`);
+    const file = fs.createWriteStream(tmpFile);
+    https.get(url, (response) => {
+      if (response.statusCode >= 300 && response.statusCode < 400 && response.headers.location) {
+        file.close();
+        fs.unlinkSync(tmpFile);
+        downloadToTempFile(response.headers.location).then(resolve).catch(reject);
+        return;
+      }
+      if (response.statusCode !== 200) {
+        file.close();
+        fs.unlinkSync(tmpFile);
+        reject(new Error(`HTTP ${response.statusCode} downloading ${url}`));
+        return;
+      }
+      response.pipe(file);
+      file.on("finish", () => {
+        file.close();
+        resolve(tmpFile);
+      });
+    }).on("error", (err) => {
+      file.close();
+      if (fs.existsSync(tmpFile)) fs.unlinkSync(tmpFile);
+      reject(err);
+    });
+  });
 }
 
-if (!fs.existsSync(venvPython())) {
-  console.log("Creating smart-search Python runtime...");
-  const created = run(python.command, [...python.args, "-m", "venv", venvDir]);
-  if (!created.ok) {
-    console.error("Failed to create the smart-search Python virtual environment.");
-    process.exit(created.status || 1);
+/**
+ * Strategy 1: python3 -m venv (works on most systems)
+ */
+function tryVenv(python) {
+  console.log("  Trying: python3 -m venv ...");
+  const result = run(python.command, [...python.args, "-m", "venv", venvDir], { stdio: "pipe" });
+  if (result.ok) return true;
+
+  const stderr = result.stderr || result.stdout || "";
+  if (stderr.includes("ensurepip") || stderr.includes("pip") || stderr.includes("venv")) {
+    console.log("  venv creation failed (likely missing ensurepip/python3-venv).");
+  } else {
+    console.log("  venv creation failed.");
   }
+  return false;
 }
 
-const py = venvPython();
+/**
+ * Strategy 2: install virtualenv via pip --user, then use it
+ */
+function tryVirtualenv(python) {
+  console.log("  Trying: virtualenv fallback ...");
 
-console.log("Installing smart-search Python package...");
-const install = run(py, [
-  "-m",
-  "pip",
-  "install",
-  "--disable-pip-version-check",
-  packageRoot
-]);
+  // Check if virtualenv is already available
+  let hasVirtualenv = run(python.command, [...python.args, "-m", "virtualenv", "--version"], { stdio: "pipe" });
+
+  if (!hasVirtualenv.ok) {
+    console.log("  virtualenv not found, installing via pip --user ...");
+    const installVenv = run(python.command, [...python.args, "-m", "pip", "install", "--user", "virtualenv"], { stdio: "pipe" });
+    if (!installVenv.ok) {
+      console.log("  Failed to install virtualenv.");
+      return false;
+    }
+  }
 
-if (!install.ok) {
-  console.error("Failed to install the bundled smart-search Python package.");
-  process.exit(install.status || 1);
+  const result = run(python.command, [...python.args, "-m", "virtualenv", venvDir], { stdio: "pipe" });
+  if (result.ok) return true;
+
+  console.log("  virtualenv failed to create the environment.");
+  return false;
 }
+
+/**
+ * Strategy 3: python3 -m venv --without-pip, then bootstrap pip
+ */
+async function tryVenvWithoutPipAsync(python) {
+  console.log("  Trying: venv --without-pip + pip bootstrap ...");
+
+  // Remove any partial venv from earlier attempts
+  if (fs.existsSync(venvDir)) {
+    fs.rmSync(venvDir, { recursive: true, force: true });
+  }
+
+  const result = run(python.command, [...python.args, "-m", "venv", "--without-pip", venvDir], { stdio: "pipe" });
+  if (!result.ok) {
+    console.log("  venv --without-pip also failed.");
+    return false;
+  }
+
+  const py = venvPython();
+
+  // Try ensurepip.bootstrap() first
+  console.log("  Bootstrapping pip via ensurepip ...");
+  const bootstrap = run(py, ["-m", "ensurepip", "--upgrade"], { stdio: "pipe" });
+  if (bootstrap.ok) return true;
+
+  // Fall back to get-pip.py
+  console.log("  ensurepip unavailable, downloading get-pip.py ...");
+  let tmpFile;
+  try {
+    tmpFile = await downloadToTempFile("https://bootstrap.pypa.io/get-pip.py");
+  } catch (err) {
+    console.log(`  Failed to download get-pip.py: ${err.message}`);
+    return false;
+  }
+
+  try {
+    const getPipResult = run(py, [tmpFile], { stdio: "pipe" });
+    if (getPipResult.ok) return true;
+    console.log("  get-pip.py failed to install pip.");
+    return false;
+  } finally {
+    if (fs.existsSync(tmpFile)) fs.unlinkSync(tmpFile);
+  }
+}
+
+/**
+ * Create a virtual environment using the best available method.
+ * Tries: venv -> virtualenv -> venv --without-pip + pip bootstrap
+ */
+async function createVenv(python) {
+  if (tryVenv(python)) return true;
+
+  // Clean up failed attempt
+  if (fs.existsSync(venvDir)) {
+    fs.rmSync(venvDir, { recursive: true, force: true });
+  }
+
+  if (tryVirtualenv(python)) return true;
+
+  // Clean up failed attempt
+  if (fs.existsSync(venvDir)) {
+    fs.rmSync(venvDir, { recursive: true, force: true });
+  }
+
+  if (await tryVenvWithoutPipAsync(python)) return true;
+
+  return false;
+}
+
+// --- Main ---
+
+async function main() {
+  const python = findPython();
+  if (!python) {
+    console.error("smart-search requires Python 3.10 or newer.");
+    console.error("Install Python, then run: npm install -g @konbakuyomu/smart-search@latest");
+    process.exit(1);
+  }
+
+  if (!fs.existsSync(venvPython())) {
+    console.log("Creating smart-search Python runtime...");
+    const created = await createVenv(python);
+    if (!created) {
+      console.error("");
+      console.error("Failed to create the smart-search Python virtual environment.");
+      console.error("");
+      console.error("On Debian/Ubuntu, install the required package:");
+      console.error("  sudo apt install python3-venv");
+      console.error("");
+      console.error("Then retry: npm install -g @konbakuyomu/smart-search@latest");
+      process.exit(1);
+    }
+  }
+
+  const py = venvPython();
+
+  console.log("Installing smart-search Python package...");
+  const install = run(py, [
+    "-m",
+    "pip",
+    "install",
+    "--disable-pip-version-check",
+    packageRoot
+  ]);
+
+  if (!install.ok) {
+    console.error("Failed to install the bundled smart-search Python package.");
+    process.exit(install.status || 1);
+  }
+}
+
+main().catch((err) => {
+  console.error("Unexpected error during postinstall:", err.message);
+  process.exit(1);
+});