diff --git a/index.html b/index.html
index 0b37c84..8e2e410 100644
--- a/index.html
+++ b/index.html
@@ -153,10 +153,8 @@ header{display:flex;align-items:center;justify-content:space-between;padding:0 1
 .card-title svg{width:13px;height:13px;color:var(--accent)}
 
 /* Unit header */
-.unit-header{display:flex;align-items:flex-start;gap:10px;margin-bottom:18px;flex-wrap:wrap}
-.unit-back{display:flex;align-items:center;gap:5px;font-size:12px;color:var(--text2);cursor:pointer;padding:6px 10px;border:1px solid var(--border);border-radius:var(--radius-sm);transition:color .15s,border-color .15s;background:var(--surface);backdrop-filter:blur(8px);flex-shrink:0;font-family:inherit}
-.unit-back:hover{color:var(--accent);border-color:var(--accent-border)}
-.unit-meta{flex:1;min-width:0}
+.unit-header{margin-bottom:18px}
+.unit-meta{min-width:0}
 .unit-cat-badge{font-size:10px;font-weight:600;letter-spacing:.07em;text-transform:uppercase;color:var(--accent);background:var(--accent-dim);border:1px solid var(--accent-border);border-radius:20px;padding:3px 9px;display:inline-block;margin-bottom:6px}
 .unit-title{font-size:19px;font-weight:600;letter-spacing:-.01em;line-height:1.3}
 
@@ -353,10 +351,12 @@ header{display:flex;align-items:center;justify-content:space-between;padding:0 1
 .step-pip{height:4px;flex:1;border-radius:2px;background:var(--border);transition:background .3s}
 .step-pip.s-active{background:var(--accent)}
 .step-pip.s-done{background:rgba(74,222,128,.5)}
-.flash-card{background:var(--surface2);border:2px solid var(--border);border-radius:var(--radius);padding:22px 18px;text-align:center;min-height:120px;display:flex;flex-direction:column;align-items:center;justify-content:center;cursor:pointer;transition:border-color .2s,background .15s;margin-bottom:14px;user-select:none}
+.flash-card{background:var(--surface2);border:2px solid var(--border);border-radius:var(--radius);padding:22px 18px;text-align:center;min-height:120px;display:flex;flex-direction:column;align-items:center;justify-content:center;cursor:pointer;transition:border-color .2s,background .15s;margin-bottom:14px;user-select:none;-webkit-tap-highlight-color:transparent}
 .flash-card:hover{border-color:var(--accent-border);background:var(--accent-dim)}
-.flash-card-front{font-size:12px;color:var(--text3);letter-spacing:.04em;margin-bottom:4px}
-.flash-card-back{font-size:13px;color:var(--text);line-height:1.75;padding-top:12px;border-top:1px solid var(--border);width:100%;margin-top:10px}
+.flash-card-front{display:flex;flex-direction:column;align-items:center;gap:10px;width:100%}
+.flash-card-term{font-size:15px;font-weight:600;color:var(--text);line-height:1.45;letter-spacing:-.01em}
+.flash-card-hint{font-size:11px;color:var(--text3);letter-spacing:.04em}
+.flash-card-back{font-size:13px;color:var(--text);line-height:1.75;padding-top:12px;border-top:1px solid var(--border);width:100%;margin-top:0;text-align:left}
 .step-count{font-size:10px;color:var(--text3);text-align:center;margin-bottom:10px;letter-spacing:.04em}
 .s2choice{display:flex;gap:10px;margin-bottom:10px}
 .s2btn{flex:1;padding:16px 10px;border-radius:var(--radius);border:2px solid var(--border);background:var(--surface);font-size:14px;font-weight:600;color:var(--text2);cursor:pointer;transition:border-color .2s,background .15s,color .15s;font-family:'Geist',sans-serif;line-height:1.35}
@@ -590,10 +590,6 @@ header{display:flex;align-items:center;justify-content:space-between;padding:0 1
       <!-- UNIT VIEW -->
       <div x-show="currentUnit && !weakDrillActive">
         <div class="unit-header">
-          <button class="unit-back sidebar-toggle" @click="goHome()">
-            <i data-lucide="arrow-left" style="width:12px;height:12px"></i>
-            ホーム
-          </button>
           <div class="unit-meta" x-show="currentUnit">
             <div class="badge-row">
               <div class="unit-cat-badge" x-text="currentUnit?.catLabel"></div>
@@ -638,13 +634,14 @@ header{display:flex;align-items:center;justify-content:space-between;padding:0 1
               Step 1 — 用語確認
             </div>
             <div class="step-count" x-text="(stepKpIdx+1) + ' / ' + (currentUnit?.keypoints?.length||0) + ' ポイント'"></div>
-            <div class="flash-card" @click="revealFlash()">
-              <div class="flash-card-front">タップして確認</div>
+            <div class="flash-card" role="button" tabindex="0" :aria-expanded="stepFlashRevealed"
+              @click="revealFlash()" @keydown.enter.prevent="revealFlash()" @keydown.space.prevent="revealFlash()">
+              <div class="flash-card-front" x-show="!stepFlashRevealed && keypointHasFlip(stepKpIdx)">
+                <div class="flash-card-term" x-text="keypointTerm(stepKpIdx)"></div>
+                <div class="flash-card-hint">タップして全文を表示</div>
+              </div>
               <div class="flash-card-back" x-show="stepFlashRevealed"
                 x-html="currentUnit?.keypoints?.[stepKpIdx]"></div>
-              <div x-show="!stepFlashRevealed" style="font-size:11px;color:var(--text3);margin-top:8px">
-                ポイント <span x-text="stepKpIdx+1"></span>
-              </div>
             </div>
             <div class="step-action-row">
               <button class="btn-sm btn-accent" @click="nextStepFlash()" x-show="stepFlashRevealed">
@@ -1547,7 +1544,7 @@ function bokiApp(){
       this.stepMode=true;
       this.stepStep=1;
       this.stepKpIdx=0;
-      this.stepFlashRevealed=false;
+      this.resetFlashRevealState();
       this.stepDrillIdx=0;
       this.stepDrillAnswered=false;
       this.stepDrillSelected=-1;
@@ -1567,14 +1564,42 @@ function bokiApp(){
       if(this.stepStep>n) return 's-done';
       return '';
     },
+    _kpDelimiterIndex(kp){
+      if(!kp||typeof kp!=='string') return -1;
+      const iw=kp.indexOf('：');
+      const ia=kp.indexOf(':');
+      if(iw<0&&ia<0) return -1;
+      if(iw<0) return ia;
+      if(ia<0) return iw;
+      return Math.min(iw,ia);
+    },
+    keypointHasFlip(idx){
+      const kp=(this.currentUnit?.keypoints||[])[idx];
+      const i=this._kpDelimiterIndex(kp);
+      return i>0;
+    },
+    keypointTerm(idx){
+      const kp=(this.currentUnit?.keypoints||[])[idx];
+      const i=this._kpDelimiterIndex(kp);
+      return i>0 ? kp.slice(0,i).trim() : '';
+    },
+    resetFlashRevealState(){
+      this.stepFlashRevealed=!this.keypointHasFlip(this.stepKpIdx);
+    },
     revealFlash(){
+      if(!this.keypointHasFlip(this.stepKpIdx)){
+        return;
+      }
+      if(this.stepFlashRevealed){
+        return;
+      }
       this.stepFlashRevealed=true;
     },
     nextStepFlash(){
       const kps=this.currentUnit?.keypoints||[];
       if(this.stepKpIdx<kps.length-1){
         this.stepKpIdx++;
-        this.stepFlashRevealed=false;
+        this.resetFlashRevealState();
       } else {
         // All keypoints done — go to step 2 (or 3 if no drills)
         const drills=DRILLS[this.currentUnit?.id]||[];
diff --git a/sw.js b/sw.js
index 64e558c..6ee6b5d 100644
--- a/sw.js
+++ b/sw.js
@@ -1,5 +1,5 @@
 // posimai-boki SW — stale-while-revalidate + skipWaiting
-const CACHE = 'posimai-boki-v10';
+const CACHE = 'posimai-boki-v12';
 const STATIC = ['/', '/index.html', '/manifest.json', '/logo.png'];
 
 self.addEventListener('install', e => {