textarea组件和input组件设置一样的placeholder-class，textarea组件渲染的字体效果不一致，比较粗。

.g-placeholder {   color: #A7A7A7;   font-size: 28rpx;   font-weight: 200;   font-family: -apple-system-font, "PingFang SC", "Helvetica Neue", Helvetica, sans-serif; }

CSS样式

<textarea class="input" value="{{deman}}" type="text" placeholder="如：我想了解产品细节；我想知道产品价格等"                 placeholder-class="g-placeholder"                 maxlength="100"                 cursor-spacing="50"                 class="deman"                 bindinput="handleInputDemand"/>

textarea代码

<input class="input" value="{{mobile}}" type="number" placeholder="请填写您的手机号"                 placeholder-class="g-placeholder"                 maxlength="11"                 bindinput="handleInputMobile"/>

input的代码

环境信息：

iOS 11.0.1 系统

微信版本：6.5.20