方向で高さが縮むタブナビゲーション

<div class="d08-13-11-stage">
          <div class="d08-13-11-tabs">
            <span class="d08-13-11-tab is-active">概要</span>
            <span class="d08-13-11-tab">詳細</span>
            <span class="d08-13-11-tab">レビュー</span>
          </div>
          <div class="d08-13-11-scroll">
            <div class="d08-13-11-body">
              <p>↓ 下スクロールでタブが縮小 / ↑ 上スクロールで通常表示</p>
              <div class="d08-13-11-block"></div>
              <div class="d08-13-11-block"></div>
              <div class="d08-13-11-block"></div>
              <div class="d08-13-11-block"></div>
            </div>
          </div>
        </div>

.prev.d08-13-11{padding:0;display:block}
        .d08-13-11-stage{position:relative;width:100%;height:100%;min-height:260px;overflow:hidden;background:#fefce8}
        .d08-13-11-tabs{
          position:absolute;top:0;left:0;right:0;z-index:2;height:46px;
          display:flex;align-items:center;justify-content:center;gap:14px;
          background:#fff;box-shadow:0 2px 8px rgba(0,0,0,.08);
          transition:height .3s ease;
        }
        .d08-13-11-stage.is-down .d08-13-11-tabs{height:30px}
        .d08-13-11-tab{font-size:12px;font-weight:700;color:#a16207;transition:font-size .3s ease,opacity .3s ease}
        .d08-13-11-tab.is-active{color:#854d0e;border-bottom:2px solid #ca8a04;padding-bottom:2px}
        .d08-13-11-stage.is-down .d08-13-11-tab{font-size:9.5px}
        .d08-13-11-scroll{position:absolute;inset:0;overflow-y:auto;padding-top:46px;transition:padding-top .3s ease}
        .d08-13-11-stage.is-down .d08-13-11-scroll{padding-top:30px}
        .d08-13-11-body{padding:16px}
        .d08-13-11-body p{font-size:11.5px;color:#a16207;margin:0 0 12px;text-align:center}
        .d08-13-11-block{height:70px;border-radius:8px;margin-bottom:12px;background:linear-gradient(135deg,#fef9c3,#fde047)}

(function(){
        var stage=document.querySelector('.d08-13-11-stage');
        if(!stage)return;
        var scroller=stage.querySelector('.d08-13-11-scroll');
        var last=0;
        scroller.addEventListener('scroll',function(){
          var top=scroller.scrollTop;
          if(top>last+2){stage.classList.add('is-down');}
          else if(top<last-2){stage.classList.remove('is-down');}
          last=top<=0?0:top;
        });
      })();