diff --git a/index.html b/index.html
index 0b08969..86aa673 100644
--- a/index.html
+++ b/index.html
@@ -107,7 +107,6 @@
       </main>
 
       <main class="grid plan" id="view-plan" hidden>
-        <div class="viewer-slot" id="slot-plan"></div>
         <aside class="panel piers" aria-labelledby="plan-pier-title">
           <p id="plan-pier-title" class="lbl">교각 목록</p>
           <div class="phead" aria-hidden="true"><span></span><span>교각</span><span>변경</span></div>
@@ -116,6 +115,8 @@
           <ul id="members" class="members"></ul>
         </aside>
 
+        <div class="center-col">
+          <div class="viewer-slot" id="slot-plan"></div>
         <section class="panel viewer" aria-labelledby="member-title">
           <div class="viewer-head">
             <h2 id="member-title">코핑</h2>
@@ -126,6 +127,7 @@
           <p id="member-note" class="muted small"></p>
           <button id="member-regen" class="btn primary" type="button" disabled>다시 생성 · 변경 0</button>
         </section>
+        </div>
 
         <aside class="panel results" aria-labelledby="changes-title">
           <h2 id="changes-title">기본값 대비 변경</h2>
@@ -136,7 +138,6 @@
       </main>
 
       <main class="grid rebar" id="view-rebar" hidden>
-        <div class="viewer-slot" id="slot-rebar"></div>
         <aside class="panel piers" aria-labelledby="rebar-pier-title">
           <p id="rebar-pier-title" class="lbl">교각 목록</p>
           <div class="phead" aria-hidden="true"><span></span><span>교각</span><span>배근</span></div>
@@ -150,11 +151,14 @@
           <ul id="rebar-tabs" class="members"></ul>
           <p class="pnote">형상은 ② 형상계획 기준입니다. 형상이 바뀌면 "형상 바뀜"으로 표시합니다.</p>
         </aside>
+        <div class="center-col">
+          <div class="viewer-slot" id="slot-rebar"></div>
         <section class="panel viewer" aria-labelledby="rebar-title">
           <div class="viewer-head"><h2 id="rebar-title">철근표</h2></div>
           <p id="rebar-note" class="num"></p>
           <div id="rebar-table"></div>
         </section>
+        </div>
         <aside class="panel results" aria-labelledby="rebar-issues-title">
           <h2 id="rebar-issues-title">알림</h2>
           <ul id="rebar-issues" class="issues"></ul>
diff --git a/src/style.css b/src/style.css
index b165a56..6ab5d23 100644
--- a/src/style.css
+++ b/src/style.css
@@ -661,7 +661,6 @@ body { background: #eef1f4; font-family: 'Noto Sans KR', system-ui, sans-serif;
 .member[aria-pressed='true'] { background: #e3edf8; color: #123e70; font-weight: 700; }
 #member-fields { margin-top: 10px; }
 #member-summary { color: #55606e; margin: 4px 0 8px; }
-.plan .viewer { flex: 1 1 380px; }
 .plan .results { flex: 1 1 300px; max-width: 360px; }
 /* 형상 선택칩 (C5) and the scrolling pier list (C6) */
 .shape-options { display: grid; gap: 6px; margin: 6px 0 10px; }
@@ -688,6 +687,9 @@ body { background: #eef1f4; font-family: 'Noto Sans KR', system-ui, sans-serif;
 .rebar-table th:nth-child(10) { text-align: right; }
 .rebar-table td:nth-child(12) { white-space: normal; min-width: 240px; }
 /* 3D viewer shared by ①, ②, ③: the slot takes the full width above the other columns */
-.viewer-slot { flex: 1 1 100%; min-width: 0; }
+.viewer-slot { flex: none; width: 100%; min-width: 0; }
 .viewer-slot > .viewer { width: 100%; }
+/* ② and ③ use the ① layout: list | model above the table | results */
+.center-col { flex: 999 1 560px; min-width: 0; display: flex; flex-direction: column; gap: 16px; }
+.center-col > .viewer { flex: none; }