<!-- 游戏主区域 -->
<div class="game-area">
  <!-- 棋盘区域 -->
  <div class="board-container">
    <canvas id="chessBoard" width="450" height="500"></canvas>
  </div>

  <!-- 侧边控制面板 -->
  <div class="side-panel">
    <!-- 控制按钮 -->
    <div class="control-panel">
      <button class="btn btn-primary" onclick="newGame()">新游戏</button>
      <button class="btn btn-success" onclick="toggleAI()" id="aiToggle">AI：开启</button>
      <button class="btn btn-warning" onclick="undoMove()">悔棋</button>
      <button class="btn btn-danger" onclick="resetGame()">重置</button>
    </div>

    <!-- 难度选择 -->
    <div class="difficulty-selector">
      <label>AI难度设置：</label>
      <div class="difficulty-buttons">
        <button class="difficulty-btn" onclick="setDifficulty(2, this)">简单</button>
        <button class="difficulty-btn active" onclick="setDifficulty(3, this)">中级</button>
        <button class="difficulty-btn" onclick="setDifficulty(4, this)">困难</button>
        <button class="difficulty-btn" onclick="setDifficulty(6, this)">专家</button>
      </div>
    </div>

    <!-- AI信息 -->
    <div class="ai-info">
      <h3>🤖 AI思考信息</h3>
      <div class="ai-stats" id="aiStats">
        <div class="stat-item">
          <span class="stat-label">搜索深度：</span>
          <span class="stat-value" id="searchDepth">3</span>
        </div>
        <div class="stat-item">
          <span class="stat-label">搜索节点：</span>
          <span class="stat-value" id="searchNodes">0</span>
        </div>
        <div class="stat-item">
          <span class="stat-label">评估分值：</span>
          <span class="stat-value" id="evalScore">0</span>
        </div>
        <div class="stat-item">
          <span class="stat-label">思考时间：</span>
          <span class="stat-value" id="thinkTime">0ms</span>
        </div>
      </div>
    </div>

    <!-- 历史记录 -->
    <div class="move-history">
      <h3>📜 走棋记录</h3>
      <ul id="historyList"></ul>
    </div>
  </div>
</div>