diff --git a/static/src/components/chat/MarkdownRenderer.vue b/static/src/components/chat/MarkdownRenderer.vue
index 238c1837..9e0ea153 100644
--- a/static/src/components/chat/MarkdownRenderer.vue
+++ b/static/src/components/chat/MarkdownRenderer.vue
@@ -23,7 +23,7 @@
 </template>
 
 <script setup lang="ts">
-import { computed, inject, nextTick, onMounted, onUpdated, ref, watch } from 'vue';
+import { computed, inject, nextTick, onBeforeUnmount, onMounted, onUpdated, ref, watch } from 'vue';
 import CodeBlock from './CodeBlock.vue';
 import {
   parseMarkdownSegments,
@@ -32,6 +32,7 @@ import {
   type MarkdownSegment
 } from '@/composables/useMarkdownRenderer';
 import { chunkRenderedHtml, type HtmlChunk } from '@/utils/htmlChunks';
+import { classifyMarkdownTables, observeMarkdownTables } from '@/utils/tableLayout';
 import { enhanceCitationChips, type CitationAnnotation } from './citationChips';
 
 defineOptions({ name: 'MarkdownRenderer' });
@@ -105,6 +106,27 @@ function enhanceCitations() {
 onMounted(enhanceCitations);
 onUpdated(enhanceCitations);
 watch(() => [props.citations, props.citationsFinal], enhanceCitations);
+
+// 表格布局模式（换行/横向滚动）：渲染后按内容自然宽度判定，并监听容器宽度变化重判
+let stopTableObserver: (() => void) | null = null;
+
+function classifyTables() {
+  nextTick(() => {
+    const el = containerRef.value;
+    if (!el) return;
+    classifyMarkdownTables(el);
+    stopTableObserver?.();
+    stopTableObserver = observeMarkdownTables(el);
+  });
+}
+
+onMounted(classifyTables);
+onUpdated(classifyTables);
+watch(() => props.content, classifyTables);
+onBeforeUnmount(() => {
+  stopTableObserver?.();
+  stopTableObserver = null;
+});
 </script>
 
 <style scoped>
diff --git a/static/src/styles/components/chat/_chat-area.scss b/static/src/styles/components/chat/_chat-area.scss
index 0509155f..ac128c61 100644
--- a/static/src/styles/components/chat/_chat-area.scss
+++ b/static/src/styles/components/chat/_chat-area.scss
@@ -872,17 +872,22 @@
   background: transparent;
 }
 
+/* 与正文表格同一横线风格：无外框/无竖线/无底色块；
+   布局模式（换行/横向滚动）由 utils/tableLayout.ts 判定 */
 .user-message.user-message--multi-agent .bubble-text .md-table-scroll,
 .user-message.user-message--multi-agent .bubble-text [data-md-table-scroll='1'] {
   display: block;
   width: auto;
   max-width: none;
   margin: 10px 0;
+  overflow: hidden;
+}
+
+.user-message.user-message--multi-agent .bubble-text .md-table-scroll[data-md-table-mode='scroll'],
+.user-message.user-message--multi-agent .bubble-text [data-md-table-scroll='1'][data-md-table-mode='scroll'] {
   overflow-x: auto;
   overflow-y: hidden;
-  border: 1px solid var(--border-default);
-  border-radius: 8px;
-  background: color-mix(in srgb, var(--text-primary) 4%, var(--chip-bg));
+  -webkit-overflow-scrolling: touch;
 }
 
 .user-message.user-message--multi-agent .bubble-text .md-table-scroll > table,
@@ -890,18 +895,38 @@
   margin: 0;
 }
 
+.user-message.user-message--multi-agent .bubble-text [data-md-table-mode='scroll'] > table {
+  width: max-content;
+  min-width: 100%;
+}
+
+.user-message.user-message--multi-agent .bubble-text [data-md-table-mode='scroll'] > table td {
+  white-space: nowrap;
+}
+
 .user-message.user-message--multi-agent .bubble-text th,
 .user-message.user-message--multi-agent .bubble-text td {
-  border: 1px solid var(--border-default);
-  padding: 6px 10px;
+  border: none;
+  padding: 8px 14px 8px 0;
   text-align: left;
-  vertical-align: middle;
+  vertical-align: top;
   font-size: 14px;
 }
 
-.user-message.user-message--multi-agent .bubble-text th {
+.user-message.user-message--multi-agent .bubble-text th:last-child,
+.user-message.user-message--multi-agent .bubble-text td:last-child {
+  padding-right: 0;
+}
+
+.user-message.user-message--multi-agent .bubble-text thead th {
   font-weight: 600;
-  background: color-mix(in srgb, var(--text-primary) 7%, var(--chip-bg));
+  white-space: nowrap;
+  border-bottom: 1.5px solid var(--border-strong);
+}
+
+.user-message.user-message--multi-agent .bubble-text tbody td {
+  border-bottom: 1px solid var(--border-default);
+  overflow-wrap: break-word;
 }
 
 .message-block--last
@@ -2187,12 +2212,14 @@ show-html[data-rendered='1'] {
   animation: none !important; /* 防止外部动画样式影响代码块，导致视觉抖动 */
 }
 
+/* 表格：清爽横线风格（无外框/无竖线/无底色块）。
+   布局模式由 utils/tableLayout.ts 按内容自然宽度判定：
+   默认换行模式（表格占满内容区、单元格折行）；
+   自然宽度超过阈值时容器打 data-md-table-mode='scroll'，退化为整表横向滚动。 */
 .text-output .text-content table {
-  width: max-content;
-  min-width: 100%;
+  width: 100%;
   border-collapse: collapse;
   margin: 0;
-  background: var(--theme-surface-soft);
 }
 
 .text-output .text-content .md-table-scroll,
@@ -2200,14 +2227,16 @@ show-html[data-rendered='1'] {
   display: block;
   width: auto;
   max-width: none;
-  margin: 16px calc(var(--chat-content-x) * -1);
+  margin: 12px calc(var(--chat-content-x) * -1);
+  padding: 0 var(--chat-content-x);
+  overflow: hidden;
+}
+
+.text-output .text-content .md-table-scroll[data-md-table-mode='scroll'],
+.text-output .text-content [data-md-table-scroll='1'][data-md-table-mode='scroll'] {
   overflow-x: auto;
   overflow-y: hidden;
   -webkit-overflow-scrolling: touch;
-  border: 1px solid var(--border-default);
-  border-radius: 12px;
-  background: var(--theme-surface-soft);
-  box-shadow: none;
 }
 
 .text-output .text-content .md-table-scroll > table,
@@ -2215,47 +2244,62 @@ show-html[data-rendered='1'] {
   margin: 0;
 }
 
-.text-output .text-content .md-table-scroll::-webkit-scrollbar,
-.text-output .text-content [data-md-table-scroll='1']::-webkit-scrollbar {
-  height: 10px;
+.text-output .text-content [data-md-table-mode='scroll'] > table {
+  width: max-content;
+  min-width: 100%;
 }
 
-.text-output .text-content .md-table-scroll::-webkit-scrollbar-track,
-.text-output .text-content [data-md-table-scroll='1']::-webkit-scrollbar-track {
-  background: color-mix(in srgb, var(--theme-surface-muted) 70%, transparent);
-  border-radius: 999px;
-  margin: 0 8px 6px;
+.text-output .text-content [data-md-table-mode='scroll'] > table td {
+  white-space: nowrap;
 }
 
-.text-output .text-content .md-table-scroll::-webkit-scrollbar-thumb,
-.text-output .text-content [data-md-table-scroll='1']::-webkit-scrollbar-thumb {
-  background: color-mix(in srgb, var(--text-secondary) 55%, transparent);
+/* 细滚动条仅在滚动模式出现 */
+.text-output .text-content .md-table-scroll[data-md-table-mode='scroll']::-webkit-scrollbar,
+.text-output .text-content [data-md-table-scroll='1'][data-md-table-mode='scroll']::-webkit-scrollbar {
+  height: 8px;
+}
+
+.text-output .text-content .md-table-scroll[data-md-table-mode='scroll']::-webkit-scrollbar-track,
+.text-output .text-content [data-md-table-scroll='1'][data-md-table-mode='scroll']::-webkit-scrollbar-track {
+  background: transparent;
+}
+
+.text-output .text-content .md-table-scroll[data-md-table-mode='scroll']::-webkit-scrollbar-thumb,
+.text-output .text-content [data-md-table-scroll='1'][data-md-table-mode='scroll']::-webkit-scrollbar-thumb {
+  background: color-mix(in srgb, var(--text-secondary) 45%, transparent);
   border-radius: 999px;
 }
 
-.text-output .text-content .md-table-scroll,
-.text-output .text-content [data-md-table-scroll='1'] {
-  scrollbar-color: color-mix(in srgb, var(--text-secondary) 55%, transparent)
-    color-mix(in srgb, var(--theme-surface-muted) 70%, transparent);
+.text-output .text-content .md-table-scroll[data-md-table-mode='scroll'],
+.text-output .text-content [data-md-table-scroll='1'][data-md-table-mode='scroll'] {
+  scrollbar-color: color-mix(in srgb, var(--text-secondary) 45%, transparent) transparent;
   scrollbar-width: thin;
 }
 
-.text-output .text-content thead {
-  background: var(--theme-chip-bg);
-}
-
 .text-output .text-content th,
 .text-output .text-content td {
-  border: 1px solid var(--border-default);
-  padding: 10px 14px;
+  border: none;
+  padding: 11px 18px 11px 0;
   text-align: left;
-  vertical-align: middle;
+  vertical-align: top;
   font-size: 14px;
 }
 
-.text-output .text-content th {
+.text-output .text-content th:last-child,
+.text-output .text-content td:last-child {
+  padding-right: 0;
+}
+
+.text-output .text-content thead th {
   font-weight: 600;
   color: var(--text-primary);
+  white-space: nowrap;
+  border-bottom: 1.5px solid var(--border-strong);
+}
+
+.text-output .text-content tbody td {
+  border-bottom: 1px solid var(--border-default);
+  overflow-wrap: break-word;
 }
 
 .text-output .text-content hr {
@@ -2690,14 +2734,7 @@ body[data-theme='dark'] {
     color: var(--text-primary);
   }
 
-  /* 表格 */
-  .text-output .text-content table {
-    background: var(--badge-bg);
-  }
-
-  .text-output .text-content thead {
-    background: var(--surface-panel);
-  }
+  /* 表格为无底色横线风格，三主题通用，无需覆盖 */
 
   /* 滚动锁定按钮 */
   .scroll-lock-btn {
@@ -2748,9 +2785,10 @@ body[data-theme='dark'] {
 
 /* ========== 明亮主题变体（对话区组件） ========== */
 /* 背景：浅色主题表面 token 阶梯近乎纯平（base/card/raised 全为 #ffffff），
-   基础样式中代码块白底落白底、表格 #f9f9f9 落白底均不可见；
+   基础样式中代码块白底落白底不可见；
    参照上方深色覆盖块的做法，按用户确认的方向做组件级补偿：
-   代码块仅头部着色、代码区与对话底保持同色；表格白体+浅灰表头+可见边框。 */
+   代码块仅头部着色、代码区与对话底保持同色。
+   表格为无底色横线风格，三主题通用，无需补偿。 */
 body[data-theme='light'] {
   /* 代码块 - 头部浅灰、代码区与对话底同为白色，外框加强到可见 */
   .code-block-wrapper {
@@ -2761,24 +2799,4 @@ body[data-theme='light'] {
     background: var(--surface-muted);
     border-bottom-color: var(--border-strong);
   }
-
-  /* 表格 - 白体 + 浅灰表头 + 可见边框 */
-  .text-output .text-content table {
-    background: var(--surface-raised);
-  }
-
-  .text-output .text-content thead {
-    background: var(--surface-muted);
-  }
-
-  .text-output .text-content th,
-  .text-output .text-content td {
-    border-color: var(--border-strong);
-  }
-
-  .text-output .text-content .md-table-scroll,
-  .text-output .text-content [data-md-table-scroll='1'] {
-    border-color: var(--border-strong);
-    background: var(--surface-raised);
-  }
 }
diff --git a/static/src/utils/tableLayout.ts b/static/src/utils/tableLayout.ts
new file mode 100644
index 00000000..104af891
--- /dev/null
+++ b/static/src/utils/tableLayout.ts
@@ -0,0 +1,87 @@
+/**
+ * Markdown 表格布局模式判定（换行 / 横向滚动）。
+ *
+ * 测量表格内容的自然宽度（所有单元格单行不折行时的宽度），与滚动容器可用宽度比较：
+ * - 自然宽度 ≤ 可用宽度 × 阈值 → 换行模式（默认，单元格折行、表格占满内容区）
+ * - 自然宽度 > 可用宽度 × 阈值 → 容器打 data-md-table-mode="scroll"，退化为整表横向滚动
+ *
+ * 样式侧见 styles/components/chat/_chat-area.scss 的表格段。
+ */
+
+/** 自然宽度超出可用宽度的该倍数以内时，仍用换行模式吸收（避免略宽一点的表被迫滚动） */
+const SCROLL_RATIO_THRESHOLD = 1.35;
+
+const MODE_ATTR = 'data-md-table-mode';
+
+const TABLE_SCROLLER_SELECTOR = '.md-table-scroll, [data-md-table-scroll="1"]';
+
+function measureNaturalWidth(table: HTMLTableElement): number {
+  // 同一帧内临时切到「自然宽度 + 全部不折行」布局测量，读完立即恢复——
+  // 浏览器不会在两次样式变更之间绘制，无闪烁
+  const prevWidth = table.style.width;
+  table.style.width = 'max-content';
+  const cells = table.querySelectorAll('th, td');
+  const savedWhiteSpace: string[] = [];
+  cells.forEach((cell, i) => {
+    const el = cell as HTMLElement;
+    savedWhiteSpace[i] = el.style.whiteSpace;
+    el.style.whiteSpace = 'nowrap';
+  });
+  const width = table.offsetWidth;
+  table.style.width = prevWidth;
+  cells.forEach((cell, i) => {
+    (cell as HTMLElement).style.whiteSpace = savedWhiteSpace[i];
+  });
+  return width;
+}
+
+function availableWidth(scroller: HTMLElement): number {
+  const style = getComputedStyle(scroller);
+  return (
+    scroller.clientWidth -
+    parseFloat(style.paddingLeft || '0') -
+    parseFloat(style.paddingRight || '0')
+  );
+}
+
+function classifyOne(scroller: HTMLElement): void {
+  const table = scroller.querySelector('table');
+  if (!table) return;
+  const avail = availableWidth(scroller);
+  // 容器不可见（折叠块/未激活标签页内）时宽度为 0，跳过，等可见后由 ResizeObserver 补判
+  if (avail <= 0) return;
+  const natural = measureNaturalWidth(table);
+  const mode = natural <= avail * SCROLL_RATIO_THRESHOLD ? 'wrap' : 'scroll';
+  if (scroller.getAttribute(MODE_ATTR) !== mode) {
+    scroller.setAttribute(MODE_ATTR, mode);
+  }
+}
+
+/** 扫描 root 下所有 markdown 表格滚动容器，按当前可用宽度重新判定布局模式（幂等） */
+export function classifyMarkdownTables(root: ParentNode): void {
+  root.querySelectorAll<HTMLElement>(TABLE_SCROLLER_SELECTOR).forEach(classifyOne);
+}
+
+/**
+ * 监听 root 下所有表格滚动容器的宽度变化（窗口缩放 / 侧栏开合），宽度变化时自动重判。
+ * 返回停止函数。仅宽度变化触发，折行引起的高度变化不会重复测量。
+ */
+export function observeMarkdownTables(root: ParentNode): () => void {
+  if (typeof ResizeObserver === 'undefined') return () => {};
+  const scrollers = Array.from(root.querySelectorAll<HTMLElement>(TABLE_SCROLLER_SELECTOR));
+  if (!scrollers.length) return () => {};
+  const lastWidths = new WeakMap<HTMLElement, number>();
+  const observer = new ResizeObserver((entries) => {
+    for (const entry of entries) {
+      const el = entry.target as HTMLElement;
+      const width = entry.contentRect.width;
+      const last = lastWidths.get(el);
+      if (last === undefined || Math.abs(width - last) > 1) {
+        lastWidths.set(el, width);
+        classifyOne(el);
+      }
+    }
+  });
+  scrollers.forEach((el) => observer.observe(el));
+  return () => observer.disconnect();
+}