/* ====== 全体設定 ====== */
    body {
      font-family: "Hiragino Maru Gothic ProN", "Noto Sans JP", sans-serif;
      background: linear-gradient(135deg, #e0f2fe, #fdf4ff);
      display: flex;
      flex-direction: column;
      align-items: center;
      margin: 0;
      color: #333;
      touch-action: manipulation;
    }

    /* ====== タイトルと説明 ====== */
    h1 {
      margin: 15px 0 5px 0;
      font-size: 2rem;
      color: #ff7f50;
      text-shadow: 2px 2px 0px #fff;
    }

    .description {
      font-size: 1.2rem;
      font-weight: bold;
      color: #0284c7;
      margin-bottom: 10px;
      background: #fff;
      padding: 8px 16px;
      border-radius: 20px;
      box-shadow: 0 4px 6px rgba(0,0,0,0.1);
    }

    .highlight-red { color: #ef4444; font-size: 1.3rem; }

    /* ==========================================
       ✨ 新しく追加した「設定画面」のデザイン
       ========================================== */
    #setup-screen {
      background: #ffffff;
      padding: 20px;
      border-radius: 20px;
      box-shadow: 0 8px 16px rgba(0,0,0,0.1);
      width: 90vw;
      max-width: 500px;
      text-align: center;
      margin-top: 10px;
      border: 4px solid #bae6fd;
    }

    .setting-box {
      margin-bottom: 20px;
      background: #f8fafc;
      padding: 15px;
      border-radius: 15px;
    }

    .setting-title {
      font-size: 1.2rem;
      font-weight: bold;
      color: #334155;
      margin-bottom: 10px;
    }

    .btn-row {
      display: flex;
      justify-content: center;
      gap: 15px;
    }

    /* 選択ボタンのデザイン */
    .setting-btn {
      background: #fff;
      color: #64748b;
      border: 3px solid #cbd5e1;
      padding: 10px 15px;
      border-radius: 12px;
      font-size: 1.1rem;
      font-weight: bold;
      cursor: pointer;
      transition: all 0.2s ease;
    }

    /* 選ばれている状態（active）のデザイン */
    .setting-btn.active {
      background: #3b82f6; /* 青色に光る */
      color: #fff;
      border-color: #2563eb;
      transform: scale(1.1); /* 少し大きくして目立たせる */
      box-shadow: 0 4px 10px rgba(59, 130, 246, 0.4);
    }

    /* 大きなスタートボタン */
    #real-start-btn {
      background: #10b981;
      box-shadow: 0 6px 0 #059669;
      width: 80%;
      margin-top: 10px;
      font-size: 1.5rem;
    }

    /* ====== ゲーム画面（最初は隠しておく） ====== */
    #game-container {
      display: none; /* ← 最初は設定画面を見せるので、ここは消しておく */
      width: 100%;
      display: flex;
      flex-direction: column;
      align-items: center;
    }

    /* ====== ゲームのステータス（点数や時間） ====== */
    #status-bar {
      display: flex;
      gap: 20px;
      font-size: 1.2rem;
      font-weight: bold;
      background: #ffffff;
      padding: 10px 20px;
      border-radius: 15px;
      box-shadow: 0 4px 8px rgba(0,0,0,0.1);
      margin-bottom: 10px;
      flex-wrap: wrap;
      justify-content: center;
    }

    #timer { color: #e11d48; font-size: 1.5rem; }

    /* ====== ゲームエリア ====== */
    #game-area {
      position: relative;
      width: 90vw;
      max-width: 600px;
      height: 400px;
      background: #f0fdf4;
      border: 4px solid #4ade80;
      border-radius: 20px;
      box-shadow: 0 8px 16px rgba(0,0,0,0.1);
      overflow: hidden;
    }

    /* ====== 円（数字の的） ====== */
    .circle {
      position: absolute;
      display: flex;
      align-items: center;
      justify-content: center;
      border-radius: 50%;
      background: radial-gradient(circle at 30% 30%, #60a5fa, #2563eb);
      color: white;
      font-weight: bold;
      font-size: 1.5rem;
      cursor: pointer;
      box-shadow: 0 4px 10px rgba(37, 99, 235, 0.4);
      transition: transform 0.1s;
    }

    .circle:active {
      transform: scale(0.9);
    }

    .circle.correct {
      background: radial-gradient(circle at 30% 30%, #fde047, #f59e0b);
      transform: scale(1.2);
      opacity: 0;
      transition: all 0.3s ease-out;
    }

    /* ====== ボタン群 ====== */
    .button-group {
      display: flex;
      justify-content: center;
      flex-wrap: wrap;
      gap: 15px;
      margin-top: 20px;
      margin-bottom: 30px;
    }

    .btn {
      background: #3b82f6;
      color: #fff;
      border: none;
      border-radius: 15px;
      padding: 15px 30px;
      font-size: 1.2rem;
      font-weight: bold;
      cursor: pointer;
      box-shadow: 0 6px 0 #1d4ed8;
      transition: all 0.1s ease;
    }

    .btn:active {
      transform: translateY(6px);
      box-shadow: 0 0 0 #1d4ed8;
    }

    #sound-toggle { background: #f59e0b; box-shadow: 0 6px 0 #b45309; }
    #end-btn { background: #ef4444; box-shadow: 0 6px 0 #b91c1c; }

    /* ====== 結果表示画面 ====== */
    #result {
      display: none; 
      position: absolute;
      top: 50%;
      left: 50%;
      transform: translate(-50%, -50%);
      text-align: center;
      background: rgba(255, 255, 255, 0.95);
      padding: 30px;
      border-radius: 20px;
      border: 4px solid #ff7f50;
      box-shadow: 0 10px 25px rgba(0, 0, 0, 0.3);
      z-index: 10;
      width: 80%;
      max-width: 300px;
    }

    #result p { margin: 10px 0; }
    #result p:first-child { font-size: 1.8rem; color: #ff7f50; font-weight: bold; }
    #result p:nth-child(2) { font-size: 2.2rem; color: #e11d48; font-weight: bold; }
    
    .result-btns {
      display: flex;
      flex-direction: column;
      gap: 10px;
      margin-top: 20px;
    }
    
    .result-btns .btn {
      padding: 10px 20px;
      font-size: 1.1rem;
    }