feat: 更改对话输入框样式，黑暗模式适配；更改对话首页标题描述；更改快速开始标语，扩大了grid容器的width10px大小；

src/components/chat/ChatMain.vue

@@ -384,6 +384,7 @@ watch(
   background: #ffffff;
   overflow: hidden;
   border-radius: 15px;
+  min-height: 0;
 
   .dark & {
     background: #11111b;

src/components/chat/MessageList.vue

@@ -1,5 +1,5 @@
 <template>
-  <div ref="boxRef" style="flex: 1; position: relative">
+  <div ref="boxRef" class="message-list-container">
     <div ref="containerRef" class="message-list" @scroll="handleScroll">
       <!-- 欢迎界面 -->
       <WelcomeScreen
@@ -102,9 +102,7 @@ const newMessageCount = ref(0);
 const isAutoScrolling = ref(true);
 const lastScrollTop = ref(0);
 
-onMounted(() => {
-  containerRef.value.style.height = boxRef.value?.clientHeight + "px";
-});
+// 高度通过 CSS flex 布局自适应，不需要手动设置
 
 // 滚动处理
 function handleScroll() {
@@ -229,8 +227,14 @@ onMounted(() => {
 </script>
 
 <style lang="scss" scoped>
+.message-list-container {
+  flex: 1;
+  position: relative;
+  min-height: 0;
+}
+
 .message-list {
-  height: 500px;
+  height: 100%;
   overflow-y: auto;
   overflow-x: hidden;
   position: relative;

src/components/chat/WelcomeScreen.vue

@@ -9,7 +9,9 @@
         <div class="logo-glow"></div>
       </div>
       <h1 class="title">Kexue AI 智能助手</h1>
-      <p class="subtitle">我可以帮助你解答问题、生成内容、分析数据等</p>
+      <p class="subtitle">
+        大学生用GPT，把自己学废了? Study模式拒绝直接给答案，引导学生思考。
+      </p>
     </div>
 
     <!-- 功能卡片 -->
@@ -108,19 +110,27 @@ const features = computed(() => [
 const suggestions = computed(() => [
   {
     icon: Lightbulb,
-    text: "帮我写一个 Vue 3 组件示例",
+    text: "让可学 AI 成为我的全科学习导师",
   },
   {
     icon: Globe,
-    text: "解释一下什么是机器学习",
+    text: "让AI帮助我调试代码 (但不直接写代码)",
   },
   {
     icon: PenTool,
-    text: "帮我写一封商务邮件",
+    text: "使用 AI 提升我的创意写作技巧",
   },
   {
     icon: Code,
-    text: "如何优化 React 应用性能",
+    text: "与 AI 进行沉浸式语言对话练习",
+  },
+  {
+    icon: Code,
+    text: '让 AI 成为我的"梦想职业引路人"',
+  },
+  {
+    icon: Code,
+    text: "让 AI 扮演一位严谨的学术论文写作导师",
   },
 ]);
 </script>
@@ -265,7 +275,7 @@ const suggestions = computed(() => [
 }
 
 .quick-start {
-  max-width: 700px;
+  max-width: 710px;
   width: 100%;
   margin-bottom: 40px;
 

src/components/input/ChatInput.vue

@@ -450,8 +450,8 @@ onMounted(() => {
 
 <style lang="scss" scoped>
 .chat-input-container {
-  background: white;
-  border: 2px solid #e2e8f0;
+  background: #f3f4f5;
+  // border: 2px solid #e2e8f0;
   border-radius: 20px;
   overflow: hidden;
   transition: all 0.2s ease;
@@ -461,10 +461,10 @@ onMounted(() => {
     border-color: #374151;
   }
 
-  &.is-focused {
-    border-color: #3b82f6;
-    box-shadow: 0 0 0 4px rgba(59, 130, 246, 0.1);
-  }
+  // &.is-focused {
+  //   border-color: #3b82f6;
+  //   box-shadow: 0 0 0 4px rgba(59, 130, 246, 0.1);
+  // }
 
   &.is-expanded {
     .textarea-wrapper textarea {
@@ -509,7 +509,7 @@ onMounted(() => {
   transition: all 0.2s ease;
 
   &:hover {
-    background: #f3f4f6;
+    background: #9f9fa05c;
     color: #374151;
 
     .dark & {
@@ -593,7 +593,7 @@ onMounted(() => {
   justify-content: space-between;
   padding: 8px 16px;
   border-top: 1px solid #f3f4f6;
-  background: #fafbfc;
+  // background: #fafbfc;
 
   .dark & {
     border-top-color: #2d2d3d;
@@ -621,7 +621,7 @@ onMounted(() => {
   transition: all 0.2s ease;
 
   &:hover {
-    background: #f3f4f6;
+    background: #9f9fa05c;
     color: #374151;
 
     .dark & {