feat: 修改字母描红逻辑，添加字母手写字体

miniprogram/supportPages/mathIndex/mathIndex.wxml

@@ -0,0 +1,46 @@
+<view class="page-container">
+    <!-- 页面标题和描述 -->
+    <view class="math-page-header">
+        <!-- <view class="math-page-title">数感启蒙</view> -->
+        <view class="math-page-subtitle">
+            选择功能，生成可打印的数感启蒙涂鸦卡
+        </view>
+    </view>
+
+    <!-- 功能列表 -->
+    <view class="math-functions-list">
+        <view
+            class="math-function-item"
+            wx:for="{{functionList}}"
+            wx:key="id"
+            data-function="{{item.id}}"
+            bind:tap="openMathFunction"
+        >
+            <view class="function-item-img-wrapper">
+                <image
+                    class="function-item-img"
+                    src="{{item.img}}"
+                    mode="aspectFill"
+                ></image>
+            </view>
+            <view class="function-item-title">{{item.title}}</view>
+            <view class="function-item-desc">{{item.desc}}</view>
+        </view>
+    </view>
+
+    <!-- 使用提示 -->
+    <view class="usage-hint">
+        <view class="hint-icon">💡</view>
+        <view class="hint-text">
+            <view class="hint-title">使用提示</view>
+            <view class="hint-desc">
+                <view>1. 点击上方功能卡片选择要生成的涂鸦卡类型</view>
+                <view>2. 选择数字等参数</view>
+                <view>3. 预览生成的涂鸦卡效果</view>
+                <view>4. 下载A4格式PNG图片，打印后使用</view>
+            </view>
+        </view>
+    </view>
+    <view class="empty"></view>
+    <add-to-miniprogram-tip />
+</view>