修改配色，修改功能

codes/minipro/calculation/miniprogram/pages/date-calc/date-calc.wxml

@@ -1,11 +1,49 @@
 <!--pages/date-calc/date-calc.wxml-->
 <view class="container">
+
+  <!-- 帮助说明面板 -->
+  <view class="history-panel {{showHelp ? 'show' : ''}}" catchtouchmove="preventTouchMove" style="z-index: 200;">
+    <view class="history-mask" bindtap="toggleHelp"></view>
+    <view class="history-content help-content">
+      <view class="history-header">
+        <text class="history-title">功能说明</text>
+        <text class="history-clear" bindtap="toggleHelp">关闭</text>
+      </view>
+      <scroll-view scroll-y class="history-list help-list">
+        <view class="help-section">
+            <view class="help-item">
+                <text class="help-icon">📅</text>
+                <view class="help-text">
+                    <text class="help-h1">日期推算</text>
+                    <text class="help-p">设定一个开始日期，输入往后(+)或往前(-)推算的天数，即可计算出目标日期。底部提供常用快捷按钮。</text>
+                </view>
+            </view>
+            <view class="help-item">
+                <text class="help-icon">⏳</text>
+                <view class="help-text">
+                    <text class="help-h1">间隔计算</text>
+                    <text class="help-p">选择两个日期，计算它们之间相差多少天，并自动换算为周数和月数。</text>
+                </view>
+            </view>
+            <view class="help-item">
+                <text class="help-icon">🌙</text>
+                <view class="help-text">
+                    <text class="help-h1">农历转换</text>
+                    <text class="help-p">支持公历（阳历）与农历（阴历）互转，并显示干支纪年、生肖、节气等传统信息。</text>
+                </view>
+            </view>
+             <button class="share-btn-large" open-type="share">分享给好友</button>
+        </view>
+      </scroll-view>
+    </view>
+  </view>
   
   <!-- 顶部 Tab 切换 -->
   <view class="tab-header">
     <view class="tab-pill {{currentTab === 0 ? 'active' : ''}}" hover-class="tab-hover" bindtap="switchTab" data-index="{{0}}">日期推算</view>
     <view class="tab-pill {{currentTab === 1 ? 'active' : ''}}" hover-class="tab-hover" bindtap="switchTab" data-index="{{1}}">间隔计算</view>
     <view class="tab-pill {{currentTab === 2 ? 'active' : ''}}" hover-class="tab-hover" bindtap="switchTab" data-index="{{2}}">农历转换</view>
+    <view class="help-btn" bindtap="toggleHelp">❓</view>
   </view>
 
   <!-- ========== 模式1: 日期推算 ========== -->