🐛[BUG]输入框周围颜色不同

### 🐛 bug 描述

输入框周围颜色不同

### 💻 复现代码

div className="rounded-box full-height" >

div>
.rounded-box {
border: 1px solid #1890ff; /* 淡蓝色边框 */
border-radius: 10px; /* 圆角效果 */
padding: 20px; /* 内边距 */
background: #ffffff; /* 白色背景 */
box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1); /* 轻微阴影效果 */
/* display: flex;
flex-direction: column;
justify-content: center; */
}

/* 卡片高度适配 */
.full-height {
height: 100%;
}

### © 版本信息

- @ant-design/pro-chat 版本: pro-chat@1.15.3
- 浏览器环境
- 开发环境 [e.g. mac OS]

Start by reproducing the reported input-area color difference with @ant-design/pro-chat 1.15.3 using the supplied ProChat example and its inputAreaProps styles. Compare the surrounding .rounded-box styles with the input area and determine the intended consistent colors; done when the discrepancy is resolved and the example renders consistently.

Written by the indexing model from the issue text.