diff --git a/README.md b/README.md
index 6d4e9b0..af8cabe 100644
--- a/README.md
+++ b/README.md
@@ -58,6 +58,7 @@
 - PPT 강의 등록/시청
   - `.pptx` 파일 업로드
   - 상세에서 슬라이드 이미지(PNG)만 표시(XML 텍스트 추출 목록은 표시하지 않음)
+  - PPT/PDF(`.pdf`) 상세: **1단·2단·3단** 보기 전환(그리드), 선택값은 브라우저 `localStorage`에 저장
   - 목록 카드에 PPT 프리뷰(첫 슬라이드 제목 + 장수) 표시
   - macOS 환경에서는 `qlmanage` 기반 실제 썸네일(첫 장 이미지) 자동 생성
 - 썸네일 백그라운드 큐
diff --git a/public/styles.css b/public/styles.css
index 4eaa6f7..5b334a9 100644
--- a/public/styles.css
+++ b/public/styles.css
@@ -1323,11 +1323,73 @@ button.ai-case-inline-link:hover {
   color: #374151;
 }
 
+.ppt-tools-row {
+  display: flex;
+  flex-wrap: wrap;
+  align-items: center;
+  gap: 12px 20px;
+  justify-content: space-between;
+}
+
+.slide-layout-toggle {
+  display: inline-flex;
+  flex-wrap: wrap;
+  align-items: center;
+  gap: 6px;
+}
+
+.slide-layout-toggle-label {
+  font-size: 13px;
+  color: #6b7280;
+  margin-right: 4px;
+}
+
+.slide-layout-btn {
+  padding: 6px 12px;
+  border-radius: 8px;
+  border: 1px solid #d1d5db;
+  background: #fff;
+  color: #374151;
+  font-size: 13px;
+  cursor: pointer;
+  line-height: 1.2;
+}
+
+.slide-layout-btn:hover {
+  background: #f9fafb;
+  border-color: #9ca3af;
+}
+
+.slide-layout-btn.is-active {
+  background: #1f2937;
+  color: #fff;
+  border-color: #1f2937;
+}
+
 .slide-list {
   display: grid;
   gap: 12px;
 }
 
+.slide-list.slide-list--cols-1 {
+  grid-template-columns: minmax(0, 1fr);
+}
+
+.slide-list.slide-list--cols-2 {
+  grid-template-columns: repeat(2, minmax(0, 1fr));
+}
+
+.slide-list.slide-list--cols-3 {
+  grid-template-columns: repeat(3, minmax(0, 1fr));
+}
+
+@media (max-width: 960px) {
+  .slide-list.slide-list--cols-2,
+  .slide-list.slide-list--cols-3 {
+    grid-template-columns: minmax(0, 1fr);
+  }
+}
+
 .slide-card {
   border: 1px solid #e5e7eb;
   border-radius: 12px;
@@ -1340,6 +1402,15 @@ button.ai-case-inline-link:hover {
   font-size: 18px;
 }
 
+.slide-list.slide-list--cols-2 .slide-card h2,
+.slide-list.slide-list--cols-3 .slide-card h2 {
+  font-size: 14px;
+}
+
+.slide-list.slide-list--cols-3 .slide-card {
+  padding: 12px;
+}
+
 .slide-card header p {
   margin: 4px 0 0;
   color: #4b5563;
@@ -1351,6 +1422,13 @@ button.ai-case-inline-link:hover {
   overflow: hidden;
   background: #f3f4f6;
 }
+
+.slide-list.slide-list--cols-1 .slide-image-wrap {
+  max-width: 920px;
+  margin-left: auto;
+  margin-right: auto;
+}
+
 .slide-image {
   display: block;
   max-width: 100%;
diff --git a/views/lecture-ppt.ejs b/views/lecture-ppt.ejs
index 4d0cc35..329f388 100644
--- a/views/lecture-ppt.ejs
+++ b/views/lecture-ppt.ejs
@@ -17,8 +17,14 @@
           <h1><%= lecture.title %></h1>
           <p class="description"><%= lecture.description || "설명이 없습니다." %></p>
 
-          <div class="ppt-tools">
+          <div class="ppt-tools ppt-tools-row">
             <span>총 <b><%= slides.length %></b>장</span>
+            <div class="slide-layout-toggle" role="group" aria-label="슬라이드 한 화면 열 개수">
+              <span class="slide-layout-toggle-label">보기</span>
+              <button type="button" class="slide-layout-btn" data-cols="1" aria-pressed="true">1단</button>
+              <button type="button" class="slide-layout-btn" data-cols="2" aria-pressed="false">2단</button>
+              <button type="button" class="slide-layout-btn" data-cols="3" aria-pressed="false">3단</button>
+            </div>
           </div>
 
           <% if (typeof slidesError !== 'undefined' && slidesError && (!slideImageUrls || slideImageUrls.length === 0)) { %>
@@ -29,7 +35,7 @@
           <p class="empty">슬라이드 내용을 불러올 수 없습니다.</p>
           <% } %>
 
-          <section class="slide-list">
+          <section class="slide-list slide-list--cols-1" id="slide-list">
             <% slides.forEach((slide, index) => { %>
             <article class="slide-card">
               <header>
@@ -46,5 +52,40 @@
         </main>
       </div>
     </div>
+    <script>
+      (function () {
+        var KEY = "learningCenterSlideColumns";
+        var list = document.getElementById("slide-list");
+        var buttons = document.querySelectorAll(".slide-layout-btn");
+        if (!list || !buttons.length) return;
+
+        function applyCols(n) {
+          list.classList.remove("slide-list--cols-1", "slide-list--cols-2", "slide-list--cols-3");
+          list.classList.add("slide-list--cols-" + n);
+          buttons.forEach(function (btn) {
+            var on = btn.getAttribute("data-cols") === String(n);
+            btn.setAttribute("aria-pressed", on ? "true" : "false");
+            btn.classList.toggle("is-active", on);
+          });
+          try {
+            localStorage.setItem(KEY, String(n));
+          } catch (e) {}
+        }
+
+        var saved = null;
+        try {
+          saved = localStorage.getItem(KEY);
+        } catch (e) {}
+        var initial = saved === "2" || saved === "3" ? saved : "1";
+        applyCols(initial);
+
+        buttons.forEach(function (btn) {
+          btn.addEventListener("click", function () {
+            var n = btn.getAttribute("data-cols");
+            if (n === "1" || n === "2" || n === "3") applyCols(n);
+          });
+        });
+      })();
+    </script>
   </body>
 </html>