diff --git a/static/src/app/methods/message.ts b/static/src/app/methods/message.ts
index c042f60..7037ecd 100644
--- a/static/src/app/methods/message.ts
+++ b/static/src/app/methods/message.ts
@@ -132,6 +132,14 @@ export const messageMethods = {
     if (this.streamingUi) {
       return;
     }
+    if (!this.isConnected) {
+      this.uiPushToast({
+        title: '连接已断开',
+        message: '当前无法发送消息，请等待连接恢复后重试',
+        type: 'warning'
+      });
+      return;
+    }
     if (this.mediaUploading) {
       this.uiPushToast({
         title: '上传中',
diff --git a/static/src/components/input/InputComposer.vue b/static/src/components/input/InputComposer.vue
index ca7a632..3f96fc9 100644
--- a/static/src/components/input/InputComposer.vue
+++ b/static/src/components/input/InputComposer.vue
@@ -60,11 +60,15 @@
               +
             </button>
             <textarea
+              :key="composerInputKey"
               ref="stadiumInput"
               class="stadium-input"
               rows="1"
               :value="inputMessage"
               :disabled="!isConnected || streamingMessage || inputLocked"
+              autocomplete="off"
+              autocorrect="off"
+              autocapitalize="off"
               placeholder="输入消息... (Ctrl+Enter 发送)"
               @input="onInput"
               @focus="$emit('input-focus')"
@@ -306,12 +310,15 @@ const applyLineMetrics = (lines: number, multiline: boolean) => {
   inputStore.setInputMultiline(multiline);
 };
 
+const composerInputKey = computed(
+  () => `${props.currentConversationId || 'new'}:${props.isConnected ? 'online' : 'offline'}`
+);
+
 const adjustTextareaSize = () => {
   const textarea = stadiumInput.value;
   if (!textarea) {
     return;
   }
-  const previousHeight = textarea.offsetHeight;
   textarea.style.height = 'auto';
   const computedStyle = window.getComputedStyle(textarea);
   const lineHeight = parseFloat(computedStyle.lineHeight || '20') || 20;
@@ -320,20 +327,15 @@ const adjustTextareaSize = () => {
   const lines = Math.max(1, Math.round(targetHeight / lineHeight));
   const multiline = targetHeight > lineHeight * 1.4;
   applyLineMetrics(lines, multiline);
-
-  if (Math.abs(targetHeight - previousHeight) <= 0.5) {
-    textarea.style.height = `${targetHeight}px`;
-    return;
-  }
-  textarea.style.height = `${previousHeight}px`;
-  void textarea.offsetHeight;
-  requestAnimationFrame(() => {
-    textarea.style.height = `${targetHeight}px`;
-  });
+  textarea.style.height = `${targetHeight}px`;
 };
 
 const onInput = (event: Event) => {
   const target = event.target as HTMLTextAreaElement;
+  if (!props.isConnected || props.streamingMessage || props.inputLocked) {
+    target.value = props.inputMessage || '';
+    return;
+  }
   emit('update:input-message', target.value);
   emit('input-change');
   adjustTextareaSize();
@@ -435,6 +437,17 @@ watch(
   }
 );
 
+watch(
+  () => props.isConnected,
+  async (connected) => {
+    if (!connected && stadiumInput.value) {
+      stadiumInput.value.blur();
+    }
+    await nextTick();
+    adjustTextareaSize();
+  }
+);
+
 onMounted(() => {
   adjustTextareaSize();
 });
diff --git a/static/src/styles/components/input/_composer.scss b/static/src/styles/components/input/_composer.scss
index f958cbd..bb8555d 100644
--- a/static/src/styles/components/input/_composer.scss
+++ b/static/src/styles/components/input/_composer.scss
@@ -232,8 +232,6 @@
     display: flex;
     gap: 12px;
     transition:
-        padding 0.2s ease,
-        min-height 0.2s ease,
         box-shadow 0.45s cubic-bezier(0.4, 0, 0.2, 1),
         border-color 0.45s cubic-bezier(0.4, 0, 0.2, 1);
 }
@@ -327,8 +325,7 @@
     outline: none;
     overflow-y: auto;
     scrollbar-width: none;
-    transition: height 0.28s cubic-bezier(0.4, 0, 0.2, 1);
-    will-change: height;
+    transition: none;
 }
 
 .stadium-input:disabled {