.testHeight1 { height:800px; background:#eee; } .testHeight2 { height:200px; background:#f7ebeb; } .giftTypeBox { width:100%; border-bottom:1px solid #ddd; background:#fff; line-height:2.9rem; font-size:1.23rem; display:flex; } .giftTypeBox span { flex:auto; text-align:center; } .giftTypeBox_posif { position:fixed; left:0; top:0; z-index:9; }