// API呼び出し関数
async function callGemini(apiKey, model, prompt) {
  const API_URL = `https://generativelanguage.googleapis.com/v1beta/${model}:generateContent?key=${apiKey}`;
  const response = await fetch(API_URL, {
    method: "POST",
    headers: { "Content-Type": "application/json" },
    body: JSON.stringify({
      contents: [{ parts: [{ text: prompt }] }]
    })
  });
  return await response.json();
}