feat: 세션, 세션 종료화면 생성

.gitignore

@@ -39,3 +39,4 @@ yarn-error.log*
 # typescript
 *.tsbuildinfo
 next-env.d.ts
+.idea

.idea/vcs.xml

@@ -1,6 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<project version="4">
-  <component name="VcsDirectoryMappings">
-    <mapping directory="$PROJECT_DIR$" vcs="Git" />
-  </component>
-</project>

.idea/workspace.xml

@@ -1,67 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<project version="4">
-  <component name="AutoImportSettings">
-    <option name="autoReloadType" value="SELECTIVE" />
-  </component>
-  <component name="ChangeListManager">
-    <list default="true" id="9e413d25-a9a8-4d83-9fd6-a4d134df4e1b" name="변경" comment="">
-      <change beforePath="$PROJECT_DIR$/src/app/page.tsx" beforeDir="false" afterPath="$PROJECT_DIR$/src/app/page.tsx" afterDir="false" />
-    </list>
-    <option name="SHOW_DIALOG" value="false" />
-    <option name="HIGHLIGHT_CONFLICTS" value="true" />
-    <option name="HIGHLIGHT_NON_ACTIVE_CHANGELIST" value="false" />
-    <option name="LAST_RESOLUTION" value="IGNORE" />
-  </component>
-  <component name="Git.Settings">
-    <option name="RECENT_GIT_ROOT_PATH" value="$PROJECT_DIR$" />
-  </component>
-  <component name="ProjectColorInfo"><![CDATA[{
-  "associatedIndex": 3
-}]]></component>
-  <component name="ProjectId" id="38yBJdMOvLXJQYiNoTURYc7ZYHL" />
-  <component name="ProjectViewState">
-    <option name="hideEmptyMiddlePackages" value="true" />
-    <option name="showLibraryContents" value="true" />
-  </component>
-  <component name="PropertiesComponent"><![CDATA[{
-  "keyToString": {
-    "ModuleVcsDetector.initialDetectionPerformed": "true",
-    "RunOnceActivity.ShowReadmeOnStart": "true",
-    "dart.analysis.tool.window.visible": "false",
-    "git-widget-placeholder": "main",
-    "last_opened_file_path": "/Users/ijeongmin/Desktop/corpi/hushroom/web",
-    "node.js.detected.package.eslint": "true",
-    "node.js.detected.package.tslint": "true",
-    "node.js.selected.package.eslint": "(autodetect)",
-    "node.js.selected.package.tslint": "(autodetect)",
-    "nodejs_package_manager_path": "npm",
-    "project.structure.last.edited": "프로젝트",
-    "project.structure.proportion": "0.0",
-    "project.structure.side.proportion": "0.0",
-    "ts.external.directory.path": "/Users/ijeongmin/Desktop/corpi/hushroom/web/node_modules/typescript/lib",
-    "vue.rearranger.settings.migration": "true"
-  }
-}]]></component>
-  <component name="SharedIndexes">
-    <attachedChunks>
-      <set>
-        <option value="bundled-jdk-9823dce3aa75-fbdcb00ec9e3-intellij.indexing.shared.core-IU-251.25410.129" />
-        <option value="bundled-js-predefined-d6986cc7102b-6a121458b545-JavaScript-IU-251.25410.129" />
-      </set>
-    </attachedChunks>
-  </component>
-  <component name="TaskManager">
-    <task active="true" id="Default" summary="디폴트 작업">
-      <changelist id="9e413d25-a9a8-4d83-9fd6-a4d134df4e1b" name="변경" comment="" />
-      <created>1769761859967</created>
-      <option name="number" value="Default" />
-      <option name="presentableId" value="Default" />
-      <updated>1769761859967</updated>
-      <workItem from="1769761861354" duration="1935000" />
-    </task>
-    <servers />
-  </component>
-  <component name="TypeScriptGeneratedFilesManager">
-    <option name="version" value="3" />
-  </component>
-</project>

src/app/page.tsx

@@ -9,27 +9,20 @@ type Mode = "freeflow" | "sprint" | "deepwork";
 export default function HomePage() {
   const router = useRouter();
 
-  const startSession = useCallback(
-    (mode: Mode) => {
-      try {
-        localStorage.setItem("last_mode", mode);
-      } catch {}
-      router.push(`/session?mode=${mode}`);
-    },
+  const go = useCallback(
+    (mode: Mode) => router.push(`/session?mode=${mode}`),
     [router],
   );
 
   return (
     <main className="min-h-screen w-full bg-[#E9EEF6]">
-      {/* Top-left logo */}
       <header className="px-5 pt-6">
-        <div className="select-none text-lg font-bold tracking-tight leading-none text-slate-900">
+        <div className="select-none text-xl font-bold tracking-tight leading-none text-slate-800">
           hushroom
         </div>
       </header>
 
-      <section className="mx-auto flex min-h-[calc(100vh-56px)] max-w-lg flex-col justify-center px-5 pb-10">
-        {/* Section: Freeflow */}
+      <section className="mx-auto flex min-h-[calc(100vh-64px)] max-w-lg flex-col justify-center px-5 pb-10">
         <div className="mb-4">
           <div className="text-sm font-semibold text-slate-600">자유 세션</div>
           <div className="mt-1 text-base leading-relaxed text-slate-700">
@@ -39,15 +32,14 @@ export default function HomePage() {
 
         <button
           type="button"
-          onClick={() => startSession("freeflow")}
+          onClick={() => go("freeflow")}
           className="w-full rounded-3xl bg-[#2F6FED] px-8 py-6 text-left text-white shadow-sm transition active:scale-[0.99] hover:bg-[#295FD1]"
-          aria-label="프리플로우 세션"
+          aria-label="프리플로우"
         >
           <div className="text-2xl font-semibold">프리플로우</div>
           <div className="mt-2 text-lg opacity-90">무제한</div>
         </button>
 
-        {/* Divider + Section: Timed sessions */}
         <div className="my-8 flex items-center gap-3">
           <div className="h-px flex-1 bg-[#D7E0EE]" />
           <div className="text-sm font-semibold text-slate-600">
@@ -61,18 +53,8 @@ export default function HomePage() {
         </div>
 
         <div className="grid grid-cols-2 gap-4">
-          <ModeTile
-            title="스프린트"
-            meta="25분"
-            desc="짧게 한 번"
-            onClick={() => startSession("sprint")}
-          />
-          <ModeTile
-            title="딥워크"
-            meta="90분"
-            desc="길게 한 번"
-            onClick={() => startSession("deepwork")}
-          />
+          <ModeTile title="스프린트" meta="25분" onClick={() => go("sprint")} />
+          <ModeTile title="딥워크" meta="90분" onClick={() => go("deepwork")} />
         </div>
       </section>
     </main>
@@ -82,12 +64,10 @@ export default function HomePage() {
 function ModeTile({
   title,
   meta,
-  desc,
   onClick,
 }: {
   title: string;
   meta: string;
-  desc: string;
   onClick: () => void;
 }) {
   return (
@@ -101,7 +81,6 @@ function ModeTile({
         <div className="text-xl font-semibold text-slate-900">{title}</div>
         <div className="text-lg font-semibold text-blue-700">{meta}</div>
       </div>
-      <div className="mt-3 text-base text-slate-700">{desc}</div>
     </button>
   );
 }

src/app/session/end/page.tsx

@@ -0,0 +1,93 @@
+// app/session/end/page.tsx
+"use client";
+
+import { useRouter, useSearchParams } from "next/navigation";
+import { useMemo } from "react";
+
+type Mode = "freeflow" | "sprint" | "deepwork";
+
+const BG = "#E9EEF6";
+const BORDER = "#C9D7F5";
+const PRIMARY = "#2F6FED";
+const PRIMARY_HOVER = "#295FD1";
+
+function clampMode(v: string | null): Mode {
+  if (v === "sprint" || v === "deepwork" || v === "freeflow") return v;
+  return "freeflow";
+}
+
+function modeLabel(mode: Mode) {
+  if (mode === "sprint") return "스프린트";
+  if (mode === "deepwork") return "딥워크";
+  return "프리플로우";
+}
+
+function hhmmss(total: number) {
+  const s = Math.max(0, Math.floor(total));
+  const hh = String(Math.floor(s / 3600)).padStart(2, "0");
+  const mm = String(Math.floor((s % 3600) / 60)).padStart(2, "0");
+  const ss = String(s % 60).padStart(2, "0");
+  return `${hh}:${mm}:${ss}`;
+}
+
+export default function SessionEndPage() {
+  const router = useRouter();
+  const params = useSearchParams();
+
+  const mode = useMemo(() => clampMode(params.get("mode")), [params]);
+  const elapsed = useMemo(() => {
+    const v = Number(params.get("elapsed") ?? "0");
+    return Number.isFinite(v) ? v : 0;
+  }, [params]);
+
+  return (
+    <main className="min-h-screen w-full" style={{ backgroundColor: BG }}>
+      <header className="px-5 pt-6">
+        <div className="select-none text-xl font-bold tracking-tight leading-none text-slate-800">
+          hushroom
+        </div>
+      </header>
+
+      <section className="mx-auto flex min-h-[calc(100vh-64px)] max-w-lg flex-col justify-center px-5 pb-10 pt-6">
+        <div
+          className="rounded-3xl border bg-white px-6 py-6 shadow-sm"
+          style={{ borderColor: BORDER }}
+        >
+          <div className="text-sm font-semibold text-slate-600">
+            {modeLabel(mode)}
+          </div>
+          <div className="mt-3 text-[44px] font-semibold leading-none text-slate-900 tabular-nums">
+            {hhmmss(elapsed)}
+          </div>
+          <div className="mt-3 text-base text-slate-700">세션이 종료됐어요</div>
+        </div>
+
+        <div className="mt-5 grid grid-cols-2 gap-3">
+          <button
+            type="button"
+            onClick={() => router.push("/")}
+            className="rounded-3xl border bg-white px-5 py-4 text-base font-semibold text-slate-800 shadow-sm transition active:scale-[0.99]"
+            style={{ borderColor: BORDER }}
+          >
+            홈
+          </button>
+
+          <button
+            type="button"
+            onClick={() => router.push(`/session?mode=${mode}`)}
+            className="rounded-3xl px-5 py-4 text-base font-semibold text-white shadow-sm transition active:scale-[0.99]"
+            style={{ backgroundColor: PRIMARY }}
+            onMouseEnter={(e) =>
+              (e.currentTarget.style.backgroundColor = PRIMARY_HOVER)
+            }
+            onMouseLeave={(e) =>
+              (e.currentTarget.style.backgroundColor = PRIMARY)
+            }
+          >
+            다시
+          </button>
+        </div>
+      </section>
+    </main>
+  );
+}

src/app/session/page.tsx

@@ -0,0 +1,465 @@
+// app/session/page.tsx
+"use client";
+
+import { useRouter, useSearchParams } from "next/navigation";
+import { useEffect, useMemo, useRef, useState } from "react";
+
+type Mode = "freeflow" | "sprint" | "deepwork";
+type PresenceStatus = "focus" | "away";
+
+type Participant = {
+  id: string;
+  status: PresenceStatus;
+  lastSeen: number; // ms
+  isSelf: boolean;
+};
+
+const BG = "#E9EEF6";
+const BORDER = "#C9D7F5";
+const PRIMARY = "#2F6FED";
+const PRIMARY_HOVER = "#295FD1";
+const HOVER = "#F1F5FF";
+
+function clampMode(v: string | null): Mode {
+  if (v === "sprint" || v === "deepwork" || v === "freeflow") return v;
+  return "freeflow";
+}
+
+function modeLabel(mode: Mode) {
+  if (mode === "sprint") return "스프린트";
+  if (mode === "deepwork") return "딥워크";
+  return "프리플로우";
+}
+
+function modeDurationSeconds(mode: Mode) {
+  if (mode === "sprint") return 25 * 60;
+  if (mode === "deepwork") return 90 * 60;
+  return null; // freeflow
+}
+
+function formatHHMMSS(totalSeconds: number) {
+  const s = Math.max(0, Math.floor(totalSeconds));
+  const hh = String(Math.floor(s / 3600)).padStart(2, "0");
+  const mm = String(Math.floor((s % 3600) / 60)).padStart(2, "0");
+  const ss = String(s % 60).padStart(2, "0");
+  return `${hh}:${mm}:${ss}`;
+}
+
+/**
+ * 로컬 Presence (Supabase 교체 전용)
+ * - 같은 브라우저에서 여러 탭/창을 열면 "인원 점"이 늘어남
+ * - BroadcastChannel 미지원 환경은 localStorage 이벤트로 fallback
+ *
+ * 교체 포인트:
+ *   const { participants } = useLocalPresence(roomKey, status)
+ * 를
+ *   const { participants } = useSupabasePresence(roomKey, status)
+ * 같은 형태로 바꾸면 UI는 그대로 유지 가능
+ */
+function useLocalPresence(roomKey: string, status: PresenceStatus) {
+  const selfId = useMemo(() => {
+    // 탭 단위 고유 ID
+    const key = `hushroom:selfId:${roomKey}`;
+    const existing = sessionStorage.getItem(key);
+    if (existing) return existing;
+
+    // 짧고 충돌 확률 낮은 ID
+    const id = (crypto?.randomUUID?.() ?? `${Date.now()}-${Math.random()}`)
+      .replace(/[^a-zA-Z0-9]/g, "")
+      .slice(0, 16);
+
+    sessionStorage.setItem(key, id);
+    return id;
+  }, [roomKey]);
+
+  const [participants, setParticipants] = useState<Participant[]>(() => [
+    { id: selfId, status, lastSeen: Date.now(), isSelf: true },
+  ]);
+
+  const participantsRef = useRef<Map<string, Omit<Participant, "isSelf">>>(
+    new Map([[selfId, { id: selfId, status, lastSeen: Date.now() }]]),
+  );
+
+  const channelRef = useRef<BroadcastChannel | null>(null);
+  const heartbeatRef = useRef<number | null>(null);
+  const cleanupRef = useRef<number | null>(null);
+
+  const publish = (payload: any) => {
+    // BroadcastChannel 우선
+    if (channelRef.current) {
+      channelRef.current.postMessage(payload);
+      return;
+    }
+    // fallback: localStorage event
+    try {
+      localStorage.setItem(
+        `hushroom:presence:${roomKey}`,
+        JSON.stringify({ ...payload, _nonce: Math.random() }),
+      );
+    } catch {}
+  };
+
+  const syncStateToReact = () => {
+    const now = Date.now();
+    const arr: Participant[] = [];
+    participantsRef.current.forEach((p, id) => {
+      arr.push({
+        id,
+        status: p.status,
+        lastSeen: p.lastSeen,
+        isSelf: id === selfId,
+      });
+    });
+    // 안정적으로 정렬(자기 자신 먼저, 그 다음 최근 순)
+    arr.sort((a, b) => {
+      if (a.isSelf && !b.isSelf) return -1;
+      if (!a.isSelf && b.isSelf) return 1;
+      return b.lastSeen - a.lastSeen;
+    });
+
+    // self 상태 최신화(React state 변경 시 반영)
+    const self = participantsRef.current.get(selfId);
+    if (self) self.lastSeen = now;
+
+    setParticipants(arr);
+  };
+
+  useEffect(() => {
+    // 채널 세팅
+    if ("BroadcastChannel" in window) {
+      const bc = new BroadcastChannel(`hushroom-presence:${roomKey}`);
+      channelRef.current = bc;
+      bc.onmessage = (ev) => {
+        const msg = ev.data;
+        if (!msg || msg.roomKey !== roomKey) return;
+        if (!msg.from) return;
+
+        if (msg.type === "ping") {
+          participantsRef.current.set(msg.from, {
+            id: msg.from,
+            status: msg.status as PresenceStatus,
+            lastSeen: msg.ts ?? Date.now(),
+          });
+          syncStateToReact();
+        }
+
+        if (msg.type === "leave") {
+          participantsRef.current.delete(msg.from);
+          syncStateToReact();
+        }
+      };
+    } else {
+      // fallback: storage event
+      const onStorage = (e: StorageEvent) => {
+        if (e.key !== `hushroom:presence:${roomKey}` || !e.newValue) return;
+        try {
+          const msg = JSON.parse(e.newValue);
+          if (!msg || msg.roomKey !== roomKey) return;
+
+          if (msg.type === "ping") {
+            participantsRef.current.set(msg.from, {
+              id: msg.from,
+              status: msg.status as PresenceStatus,
+              lastSeen: msg.ts ?? Date.now(),
+            });
+            syncStateToReact();
+          }
+          if (msg.type === "leave") {
+            participantsRef.current.delete(msg.from);
+            syncStateToReact();
+          }
+        } catch {}
+      };
+      window.addEventListener("storage", onStorage);
+      return () => window.removeEventListener("storage", onStorage);
+    }
+
+    return () => {
+      channelRef.current?.close();
+      channelRef.current = null;
+    };
+    // eslint-disable-next-line react-hooks/exhaustive-deps
+  }, [roomKey]);
+
+  useEffect(() => {
+    // 내 상태 업데이트 + ping
+    const now = Date.now();
+    participantsRef.current.set(selfId, { id: selfId, status, lastSeen: now });
+    publish({ type: "ping", roomKey, from: selfId, status, ts: now });
+    syncStateToReact();
+    // eslint-disable-next-line react-hooks/exhaustive-deps
+  }, [status, roomKey, selfId]);
+
+  useEffect(() => {
+    // heartbeat: 2초마다 ping
+    heartbeatRef.current = window.setInterval(() => {
+      const now = Date.now();
+      participantsRef.current.set(selfId, {
+        id: selfId,
+        status,
+        lastSeen: now,
+      });
+      publish({ type: "ping", roomKey, from: selfId, status, ts: now });
+      syncStateToReact();
+    }, 2000);
+
+    // cleanup: 4초마다 오래된 참가자 제거(탭 닫힘 대비)
+    cleanupRef.current = window.setInterval(() => {
+      const now = Date.now();
+      const STALE_MS = 9000; // 9초 이상 ping 없으면 제거
+      let changed = false;
+
+      participantsRef.current.forEach((p, id) => {
+        if (id === selfId) return;
+        if (now - p.lastSeen > STALE_MS) {
+          participantsRef.current.delete(id);
+          changed = true;
+        }
+      });
+
+      if (changed) syncStateToReact();
+    }, 4000);
+
+    const onBeforeUnload = () => {
+      publish({ type: "leave", roomKey, from: selfId, ts: Date.now() });
+    };
+    window.addEventListener("beforeunload", onBeforeUnload);
+
+    return () => {
+      if (heartbeatRef.current) window.clearInterval(heartbeatRef.current);
+      if (cleanupRef.current) window.clearInterval(cleanupRef.current);
+      window.removeEventListener("beforeunload", onBeforeUnload);
+      publish({ type: "leave", roomKey, from: selfId, ts: Date.now() });
+    };
+    // eslint-disable-next-line react-hooks/exhaustive-deps
+  }, [roomKey, selfId, status]);
+
+  return { participants, selfId };
+}
+
+export default function SessionPage() {
+  const router = useRouter();
+  const params = useSearchParams();
+  const mode = useMemo(() => clampMode(params.get("mode")), [params]);
+  const duration = useMemo(() => modeDurationSeconds(mode), [mode]);
+
+  const [goal, setGoal] = useState("");
+  const [isAway, setIsAway] = useState(false);
+
+  // presence (로컬)
+  const presenceStatus: PresenceStatus = isAway ? "away" : "focus";
+  const roomKey = "lounge"; // 나중에 방 분리하면 여기만 바꾸면 됨
+  const { participants } = useLocalPresence(roomKey, presenceStatus);
+
+  // time
+  const [elapsed, setElapsed] = useState(0);
+  const [remaining, setRemaining] = useState(duration ?? 0);
+
+  // toast
+  const [toast, setToast] = useState<string | null>(null);
+  const toastTimerRef = useRef<number | null>(null);
+
+  // freeflow checkpoint every 60 minutes
+  const lastCheckpointRef = useRef<number>(0);
+
+  const showToast = (msg: string) => {
+    setToast(msg);
+    if (toastTimerRef.current) window.clearTimeout(toastTimerRef.current);
+    toastTimerRef.current = window.setTimeout(() => setToast(null), 8000);
+  };
+
+  useEffect(() => {
+    setElapsed(0);
+    if (duration) setRemaining(duration);
+    lastCheckpointRef.current = 0;
+    setIsAway(false);
+    setToast(null);
+    if (toastTimerRef.current) window.clearTimeout(toastTimerRef.current);
+  }, [duration]);
+
+  useEffect(() => {
+    const id = window.setInterval(() => {
+      setElapsed((prev) => prev + 1);
+
+      if (duration) {
+        setRemaining((prev) => {
+          const next = Math.max(0, prev - 1);
+          if (next === 0 && prev !== 0) {
+            router.push(`/session/end?mode=${mode}&elapsed=${duration}`);
+          }
+          return next;
+        });
+      }
+    }, 1000);
+
+    return () => window.clearInterval(id);
+  }, [duration, mode, router]);
+
+  useEffect(() => {
+    if (mode !== "freeflow") return;
+    const mins = Math.floor(elapsed / 60);
+    if (mins > 0 && mins % 60 === 0 && mins !== lastCheckpointRef.current) {
+      lastCheckpointRef.current = mins;
+      showToast(`${mins}분 지났어요`);
+    }
+  }, [elapsed, mode]);
+
+  const timeMain = useMemo(() => {
+    if (mode === "freeflow") return formatHHMMSS(elapsed);
+    return formatHHMMSS(remaining);
+  }, [elapsed, remaining, mode]);
+
+  const onCheckIn = () => showToast("체크인 기록됨");
+  const onEnd = () =>
+    router.push(`/session/end?mode=${mode}&elapsed=${elapsed}`);
+
+  return (
+    <main className="min-h-screen w-full" style={{ backgroundColor: BG }}>
+      <header className="px-5 pt-6">
+        <div className="select-none text-xl font-bold tracking-tight leading-none text-slate-800">
+          hushroom
+        </div>
+      </header>
+
+      <section className="mx-auto flex min-h-[calc(100vh-64px)] max-w-lg flex-col px-5 pb-10 pt-6">
+        {toast && (
+          <div className="mb-4 rounded-2xl border border-[#D7E0EE] bg-white px-4 py-3 text-sm text-slate-700 shadow-sm">
+            {toast}
+          </div>
+        )}
+
+        <div className="mb-4">
+          <div className="text-sm font-semibold text-slate-600">
+            {modeLabel(mode)}
+          </div>
+          <div className="mt-1 text-base leading-relaxed text-slate-700">
+            {mode === "freeflow"
+              ? "원할 때 종료"
+              : "한 번 실행되고 끝나면 요약으로 이동"}
+          </div>
+        </div>
+
+        {/* Timer */}
+        <div
+          className="rounded-3xl border bg-white px-6 py-6 shadow-sm"
+          style={{ borderColor: BORDER }}
+        >
+          <div className="text-[44px] font-semibold leading-none text-slate-900 tabular-nums">
+            {timeMain}
+          </div>
+
+          <div className="mt-6">
+            <label className="text-sm font-semibold text-slate-600">
+              목표(선택)
+            </label>
+            <input
+              value={goal}
+              onChange={(e) => setGoal(e.target.value)}
+              placeholder="이번 세션 목표(선택)"
+              className="mt-2 w-full rounded-2xl border px-4 py-3 text-base text-slate-900 outline-none"
+              style={{ borderColor: BORDER }}
+            />
+          </div>
+        </div>
+
+        {/* Presence */}
+        <div
+          className="mt-4 rounded-3xl border bg-white px-6 py-5 shadow-sm"
+          style={{ borderColor: BORDER }}
+        >
+          <div className="flex items-center justify-between">
+            <div className="text-sm font-semibold text-slate-700">방</div>
+            <div className="text-sm text-slate-600">{roomKey}</div>
+          </div>
+
+          <div className="mt-4 flex items-center justify-between">
+            <div className="text-sm font-semibold text-slate-700">인원</div>
+            <div className="text-sm text-slate-600">{participants.length}</div>
+          </div>
+
+          <div className="mt-4">
+            <PresenceDots participants={participants} />
+          </div>
+        </div>
+
+        {/* Actions */}
+        <div className="mt-5 grid grid-cols-3 gap-3">
+          <button
+            type="button"
+            onClick={() => setIsAway((v) => !v)}
+            className="rounded-3xl border bg-white px-4 py-4 text-base font-semibold text-slate-800 shadow-sm transition active:scale-[0.99]"
+            style={{ borderColor: BORDER }}
+            onMouseEnter={(e) =>
+              (e.currentTarget.style.backgroundColor = HOVER)
+            }
+            onMouseLeave={(e) =>
+              (e.currentTarget.style.backgroundColor = "#FFFFFF")
+            }
+          >
+            {isAway ? "복귀" : "자리비움"}
+          </button>
+
+          <button
+            type="button"
+            onClick={onCheckIn}
+            className="rounded-3xl border bg-white px-4 py-4 text-base font-semibold text-slate-800 shadow-sm transition active:scale-[0.99]"
+            style={{ borderColor: BORDER }}
+            onMouseEnter={(e) =>
+              (e.currentTarget.style.backgroundColor = HOVER)
+            }
+            onMouseLeave={(e) =>
+              (e.currentTarget.style.backgroundColor = "#FFFFFF")
+            }
+          >
+            체크인
+          </button>
+
+          <button
+            type="button"
+            onClick={onEnd}
+            className="rounded-3xl px-4 py-4 text-base font-semibold text-white shadow-sm transition active:scale-[0.99]"
+            style={{ backgroundColor: PRIMARY }}
+            onMouseEnter={(e) =>
+              (e.currentTarget.style.backgroundColor = PRIMARY_HOVER)
+            }
+            onMouseLeave={(e) =>
+              (e.currentTarget.style.backgroundColor = PRIMARY)
+            }
+          >
+            종료
+          </button>
+        </div>
+      </section>
+    </main>
+  );
+}
+
+function PresenceDots({ participants }: { participants: Participant[] }) {
+  const MAX = 12;
+  const visible = participants.slice(0, MAX);
+  const extra = Math.max(0, participants.length - visible.length);
+
+  return (
+    <div className="flex items-center gap-2">
+      {visible.map((p) => (
+        <Dot key={p.id} status={p.status} isSelf={p.isSelf} />
+      ))}
+      {extra > 0 && (
+        <div className="text-sm font-semibold text-slate-600">+{extra}</div>
+      )}
+    </div>
+  );
+}
+
+function Dot({ status, isSelf }: { status: PresenceStatus; isSelf: boolean }) {
+  const base = status === "away" ? "bg-slate-900/20" : "bg-slate-900/60";
+  const ring = isSelf ? "ring-2 ring-[#2F6FED]" : "ring-0";
+
+  return (
+    <div
+      className={`h-3 w-3 rounded-full ${base} ${ring}`}
+      aria-label={isSelf ? "나" : status === "away" ? "자리비움" : "집중"}
+      title={isSelf ? "나" : status === "away" ? "자리비움" : "집중"}
+    />
+  );
+}