diff --git a/web/src/app/_components/input-box.tsx b/web/src/app/_components/input-box.tsx
index f8a6b12..5f9c1b9 100644
--- a/web/src/app/_components/input-box.tsx
+++ b/web/src/app/_components/input-box.tsx
@@ -13,8 +13,14 @@ import {
 
 import { Button } from "~/components/ui/button";
 import type { Option } from "~/core/messages";
+import {
+  setEnableBackgroundInvestigation,
+  useSettingsStore,
+} from "~/core/store";
 import { cn } from "~/lib/utils";
 
+import { Detective } from "../_icons/detective";
+
 import { Tooltip } from "./tooltip";
 
 export function InputBox({
@@ -37,6 +43,9 @@ export function InputBox({
   const [message, setMessage] = useState("");
   const [imeStatus, setImeStatus] = useState<"active" | "inactive">("inactive");
   const [indent, setIndent] = useState(0);
+  const backgroundInvestigation = useSettingsStore(
+    (state) => state.general.enableBackgroundInvestigation,
+  );
   const textareaRef = useRef<HTMLTextAreaElement>(null);
   const feedbackRef = useRef<HTMLDivElement>(null);
 
@@ -137,7 +146,37 @@ export function InputBox({
         />
       </div>
       <div className="flex items-center px-4 py-2">
-        <div className="flex grow"></div>
+        <div className="flex grow">
+          <Tooltip
+            className="max-w-60"
+            title={
+              <div>
+                <h3 className="mb-2 font-bold">
+                  Investigation Mode: {backgroundInvestigation ? "On" : "Off"}
+                </h3>
+                <p>
+                  When enabled, DeerFlow will perform a quick search before
+                  planning. This is useful for researches related to ongoing
+                  events and news.
+                </p>
+              </div>
+            }
+          >
+            <Button
+              className={cn(
+                "rounded-2xl",
+                backgroundInvestigation && "!border-brand !text-brand",
+              )}
+              variant="outline"
+              size="lg"
+              onClick={() =>
+                setEnableBackgroundInvestigation(!backgroundInvestigation)
+              }
+            >
+              <Detective /> Investigation
+            </Button>
+          </Tooltip>
+        </div>
         <div className="flex shrink-0 items-center gap-2">
           <Tooltip title={responding ? "Stop" : "Send"}>
             <Button
diff --git a/web/src/app/_icons/detective.tsx b/web/src/app/_icons/detective.tsx
new file mode 100644
index 0000000..7226ad5
--- /dev/null
+++ b/web/src/app/_icons/detective.tsx
@@ -0,0 +1,26 @@
+export function Detective({ className }: { className?: string }) {
+  return (
+    <svg
+      className={className}
+      version="1.1"
+      width="800px"
+      height="800px"
+      viewBox="0 0 512 512"
+    >
+      <g fill="currentcolor">
+        <path
+          d="M392.692,257.322c-1.172-8.125-2.488-16.98-3.807-25.984c-5.856-39.012-12.59-81.688-14.86-87.832
+		c-4.318-11.715-18.371-44.723-68.217-25.984c-15.738,5.926-18.812,11.93-41.648,8.93c-17.273-2.27-28.326-15.59-52.336-24.668
+		c-49.844-18.883-71.584,11.711-75.902,23.422c-2.27,6.148-9.004,67.121-14.86,106.133c-1.39,8.86-2.633,17.566-3.804,25.621
+		c37.256,7.535,84.174,12.879,138.705,12.879C309.541,269.837,355.801,264.716,392.692,257.322z"
+        />
+        <path
+          d="M443.707,306.509c-8.051-2.196-16.834-4.246-26.057-6.148c-1.83-0.805-3.66-1.535-5.49-2.27h-0.072
+		c-46.918,10.394-102.254,15.664-156.125,15.664c-53.652,0-108.768-5.27-155.541-15.516c-1.316,0.512-2.707,1.098-4.098,1.684
+		c-8.858,1.828-17.348,3.73-25.106,5.781l-0.148,0.074C27.008,317.49,0,333.372,0,350.939c0,36.012,114.549,65.289,256.035,65.289
+		c141.34,0,255.965-29.278,255.965-65.289C512,333.74,486.016,318.22,443.707,306.509z"
+        />
+      </g>
+    </svg>
+  );
+}
diff --git a/web/src/app/page.tsx b/web/src/app/page.tsx
index 3613d0c..9950124 100644
--- a/web/src/app/page.tsx
+++ b/web/src/app/page.tsx
@@ -124,21 +124,20 @@ function Jumbotron() {
         flickerChance={0.12}
       />
       <div className="relative z-10 flex flex-col items-center justify-center gap-12">
-        <h1 className="text-center text-6xl font-bold">
+        <h1 className="text-center text-4xl font-bold md:text-6xl">
           <span className="bg-gradient-to-r from-white via-gray-200 to-gray-400 bg-clip-text text-transparent">
             Deep Research{" "}
           </span>
           <AuroraText>at Your Fingertips</AuroraText>
         </h1>
-        <p className="hidden max-w-4xl text-center text-2xl font-light opacity-75 md:block">
-          Discover the revolutionary Multi-Agent Research Assistant that
-          empowers you to dive deeper and wider into any subject. Equipped with
-          the powerful tools like search engines, crawlers, Python, and MCP
-          services, DeerFlow provides instant insights, in-depth reports and
-          even captivating podcasts.
+        <p className="max-w-4xl p-2 text-center text-sm font-light opacity-80 md:text-2xl">
+          Meet <span className="font-medium">DeerFlow</span>, your ultimate Deep
+          Research assistant. With powerful tools like search engines, web
+          crawlers, Python and MCP services, it provides instant insights,
+          comprehensive reports, or even captivating podcasts.
         </p>
         <div className="flex gap-6">
-          <Button className="w-42 text-lg" size="lg" asChild>
+          <Button className="hidden text-lg md:flex md:w-42" size="lg" asChild>
             <Link href="/chat">
               Get Started <ChevronRight />
             </Link>
@@ -211,7 +210,7 @@ const caseStudies = [
 
 function CaseStudySection() {
   return (
-    <section className="relative container flex flex-col items-center justify-center">
+    <section className="relative container hidden flex-col items-center justify-center md:flex">
       <SectionHeader
         title="Case Studies"
         description="See DeerFlow in action through replays."
diff --git a/web/src/core/api/chat.ts b/web/src/core/api/chat.ts
index 3f25edc..0a95fa2 100644
--- a/web/src/core/api/chat.ts
+++ b/web/src/core/api/chat.ts
@@ -17,6 +17,7 @@ export async function* chatStream(
     max_plan_iterations: number;
     max_step_num: number;
     interrupt_feedback?: string;
+    enable_background_investigation: boolean;
     mcp_settings?: {
       servers: Record<
         string,
diff --git a/web/src/core/store/settings-store.ts b/web/src/core/store/settings-store.ts
index d42d60b..d568f9c 100644
--- a/web/src/core/store/settings-store.ts
+++ b/web/src/core/store/settings-store.ts
@@ -10,6 +10,7 @@ const SETTINGS_KEY = "deerflow.settings";
 const DEFAULT_SETTINGS: SettingsState = {
   general: {
     autoAcceptedPlan: false,
+    enableBackgroundInvestigation: false,
     maxPlanIterations: 1,
     maxStepNum: 3,
   },
@@ -21,6 +22,7 @@ const DEFAULT_SETTINGS: SettingsState = {
 export type SettingsState = {
   general: {
     autoAcceptedPlan: boolean;
+    enableBackgroundInvestigation: boolean;
     maxPlanIterations: number;
     maxStepNum: number;
   };
@@ -48,9 +50,10 @@ export const loadSettings = () => {
   const json = localStorage.getItem(SETTINGS_KEY);
   if (json) {
     const settings = JSON.parse(json);
-    for (const key in DEFAULT_SETTINGS) {
-      if (!(key in settings)) {
-        settings[key] = DEFAULT_SETTINGS[key as keyof SettingsState];
+    for (const key in DEFAULT_SETTINGS.general) {
+      if (!(key in settings.general)) {
+        settings.general[key as keyof SettingsState["general"]] =
+          DEFAULT_SETTINGS.general[key as keyof SettingsState["general"]];
       }
     }
 
@@ -71,14 +74,14 @@ export const saveSettings = () => {
 export const getChatStreamSettings = () => {
   let mcpSettings:
     | {
-      servers: Record<
-        string,
-        MCPServerMetadata & {
-          enabled_tools: string[];
-          add_to_agents: string[];
-        }
-      >;
-    }
+        servers: Record<
+          string,
+          MCPServerMetadata & {
+            enabled_tools: string[];
+            add_to_agents: string[];
+          }
+        >;
+      }
     | undefined = undefined;
   const { mcp, general } = useSettingsStore.getState();
   const mcpServers = mcp.servers.filter((server) => server.enabled);
@@ -120,4 +123,13 @@ export const getChatStreamSettings = () => {
   };
 };
 
+export function setEnableBackgroundInvestigation(value: boolean) {
+  useSettingsStore.setState((state) => ({
+    general: {
+      ...state.general,
+      enableBackgroundInvestigation: value,
+    },
+  }));
+  saveSettings();
+}
 loadSettings();
diff --git a/web/src/core/store/store.ts b/web/src/core/store/store.ts
index d8272ac..13af2f0 100644
--- a/web/src/core/store/store.ts
+++ b/web/src/core/store/store.ts
@@ -50,7 +50,9 @@ export const useStore = create<{
     }));
   },
   updateMessage(message: Message) {
-    set(state => ({ messages: new Map(state.messages).set(message.id, message) }));
+    set((state) => ({
+      messages: new Map(state.messages).set(message.id, message),
+    }));
   },
   updateMessages(messages: Message[]) {
     set((state) => {
@@ -67,7 +69,7 @@ export const useStore = create<{
   },
   setOngoingResearch(researchId: string | null) {
     set({ ongoingResearchId: researchId });
-  }
+  },
 }));
 
 export async function sendMessage(
@@ -96,6 +98,8 @@ export async function sendMessage(
       thread_id: THREAD_ID,
       interrupt_feedback: interruptFeedback,
       auto_accepted_plan: settings.autoAcceptedPlan,
+      enable_background_investigation:
+        settings.enableBackgroundInvestigation ?? true,
       max_plan_iterations: settings.maxPlanIterations,
       max_step_num: settings.maxStepNum,
       mcp_settings: settings.mcpSettings,