/* PC端最大宽度限制 - 居中显示 */
@media (min-width: 768px) {
    body {
        max-width: 540px !important;
        margin: 0 auto !important;
        box-shadow: 0 0 30px rgba(0,0,0,0.08);
        min-height: 100vh;
        position: relative;
        background: #f7f7f7;
    }
    /* 底部导航居中 */
    .bottom-nav {
        max-width: 540px !important;
        left: 50% !important;
        transform: translateX(-50%) !important;
    }
    /* 聊天页底部输入框居中 */
    .input-area {
        max-width: 540px !important;
        left: 50% !important;
        right: auto !important;
        transform: translateX(-50%) !important;
    }
    /* 聊天页功能面板居中 */
    .more-panel, .emoji-panel {
        max-width: 540px !important;
        left: 50% !important;
        right: auto !important;
        transform: translateX(-50%) !important;
    }
    /* 弹窗居中 */
    .modal, .share-modal, .date-picker-modal, .share-mask {
        max-width: 540px !important;
        left: 50% !important;
        transform: translateX(-50%) !important;
    }
    /* 聊天区域底部留白 */
    #chatArea {
        padding-bottom: 70px !important;
    }
}