深色浅色主题切换；去掉新浪行情徽章；科技感卡片样式

Co-authored-by: Cursor <cursoragent@cursor.com>

templates/keys.html

@@ -34,7 +34,7 @@
                     <button type="submit" class="btn-primary">添加</button>
                 </div>
             </form>
-            <h3 style="font-size:.9rem;color:#a9a9ff;margin:.75rem 0 .5rem">监控列表</h3>
+            <h3 class="section-label">监控列表</h3>
             <div class="list card-scroll">
                 {% for k in keys %}
                 <div class="list-item" style="padding:.75rem;font-size:.85rem">
@@ -46,7 +46,7 @@
                     <a href="{{ url_for('del_key', pid=k.id) }}" class="btn-del" onclick="return confirm('移入历史？')">删</a>
                 </div>
                 {% else %}
-                <div style="color:#888;padding:.75rem;font-size:.85rem">暂无监控</div>
+                <div class="empty-hint">暂无监控</div>
                 {% endfor %}
             </div>
         </div>
@@ -68,7 +68,7 @@
                         <td>{{ k.archived_at[:16] if k.archived_at else '' }}</td>
                     </tr>
                     {% else %}
-                    <tr><td colspan="6" style="color:#888">暂无历史</td></tr>
+                    <tr><td colspan="6" class="text-muted">暂无历史</td></tr>
                     {% endfor %}
                 </tbody>
             </table>