スタック重なり遷移

<div class="d08-04-05-stage">
          <div class="d08-04-05-page d08-04-05-a">
            <strong>マイページ</strong>
            <p>アカウント情報</p>
          </div>
          <div class="d08-04-05-page d08-04-05-b">
            <strong>設定画面</strong>
            <p>プロフィール編集</p>
          </div>
          <button type="button" class="d08-04-05-btn">設定を開く</button>
        </div>

.prev.d08-04-05{padding:0;}
        .d08-04-05-stage{position:absolute;inset:0;overflow:hidden;font-family:sans-serif;}
        .d08-04-05-page{position:absolute;inset:0;display:flex;flex-direction:column;align-items:center;justify-content:center;gap:6px;color:#fff;}
        .d08-04-05-a{background:linear-gradient(135deg,#334155,#1e293b);}
        .d08-04-05-b{background:linear-gradient(135deg,#fb923c,#ea580c);transform:translateY(100%);box-shadow:0 -8px 24px rgba(0,0,0,.25);transition:transform .5s cubic-bezier(.22,1,.36,1);z-index:2;border-radius:16px 16px 0 0;}
        .d08-04-05-stage.is-b .d08-04-05-b{transform:translateY(0);}
        .d08-04-05-page strong{font-size:18px;}
        .d08-04-05-page p{font-size:12px;margin:0;opacity:.85;}
        .d08-04-05-btn{position:absolute;left:50%;bottom:14px;transform:translateX(-50%);z-index:3;border:none;border-radius:999px;padding:6px 16px;font-size:12px;background:#fff;color:#333;cursor:pointer;}

(function(){
          var box=document.currentScript.closest('.item').querySelector('.d08-04-05');
          var stage=box.querySelector('.d08-04-05-stage');
          var btn=box.querySelector('.d08-04-05-btn');
          var on=false;
          btn.addEventListener('click',function(){
            on=!on;
            stage.classList.toggle('is-b',on);
            btn.textContent=on?'閉じる':'設定を開く';
          });
        })();