添加区域模式，优化提示

popup.js

@@ -13,6 +13,7 @@ const intensityValue = document.getElementById('intensityValue');
 const statusDiv = document.getElementById('status');
 const modeElementBtn = document.getElementById('modeElement');
 const modeSelectionBtn = document.getElementById('modeSelection');
+const modeAreaBtn = document.getElementById('modeArea');
 const usageTip = document.getElementById('usageTip');
 
 // 从存储中加载模糊强度
@@ -41,7 +42,7 @@ blurIntensitySlider.addEventListener('input', (e) => {
 });
 
 // 模式切换
-[modeElementBtn, modeSelectionBtn].forEach(btn => {
+[modeElementBtn, modeSelectionBtn, modeAreaBtn].forEach(btn => {
   btn.addEventListener('click', () => {
     const mode = btn.dataset.mode;
     currentMode = mode;
@@ -75,7 +76,7 @@ function updateUsageTip(mode) {
       3. 点击元素进行模糊<br>
       4. 再次点击取消模糊
     `;
-  } else {
+  } else if (mode === 'selection') {
     usageTip.innerHTML = `
       <strong>文本选择模式：</strong><br>
       1. 点击"开启模糊模式"<br>
@@ -83,6 +84,14 @@ function updateUsageTip(mode) {
       3. 点击浮动按钮模糊文本<br>
       4. 可多次选择和模糊
     `;
+  } else if (mode === 'area') {
+    usageTip.innerHTML = `
+      <strong>区域模式：</strong><br>
+      1. 点击"开启模糊模式"<br>
+      2. 拖动鼠标绘制矩形区域<br>
+      3. 释放鼠标创建模糊区域<br>
+      4. 点击区域恢复
+    `;
   }
 }