style(页面样式): 为学校名称字段添加选中和占位符样式

@@ -99,7 +99,7 @@
                         <text class="form-label">所在学校</text>
                     </view>
                     <view class="form-item-right">
-                        <text class="form-value">{{ formData.school_name || '请选择' }}</text>
+                        <text class="form-value" :class="{ 'form-value-selected': formData.school_name, 'form-value-placeholder': !formData.school_name }">{{ formData.school_name || '请选择' }}</text>
                         <Right class="arrow-icon" />
                     </view>
                 </view>