修正

frontend/css/mobile.css

@@ -323,4 +323,58 @@ html {
     width: 100% !important;
     box-sizing: border-box !important;
   }
+
+  /* ── split-layout: PC は左右分割、モバイルは上下積み ── */
+  /* 左リスト・右明細を縦方向に並べ直す */
+  .split-layout {
+    flex-direction: column !important;
+  }
+
+  .split-left {
+    flex: none !important;
+    width: 100% !important;
+    max-width: none !important;
+    min-width: 0 !important;
+    max-height: none !important;
+    overflow-y: visible !important;
+    position: static !important;
+  }
+
+  .split-right {
+    width: 100% !important;
+    min-width: 0 !important;
+    border-left: none !important;
+    border-top: 2px solid #e0e8f0 !important;
+    padding-left: 0 !important;
+    padding-top: 16px !important;
+    margin-top: 8px !important;
+    max-height: none !important;
+    overflow-y: visible !important;
+    position: static !important;
+  }
+
+  /* ── タブ（給与計算・賞与計算・帳票出力）を折り返し ── */
+  .nav-tabs-calc {
+    flex-wrap: wrap !important;
+    gap: 6px !important;
+    border-bottom: none !important;
+  }
+
+  .nav-tab-calc {
+    padding: 8px 14px !important;
+    font-size: 0.9rem !important;
+    border-radius: 6px !important;
+  }
+
+  /* ── 新規計算モーダル（inline style の width:800px を上書き） ── */
+  #calculateModal,
+  #bonusModal {
+    width: 92vw !important;
+    left: 4vw !important;
+    transform: none !important;
+    max-width: 92vw !important;
+    padding: 20px 16px !important;
+    box-sizing: border-box !important;
+  }
+
 }