header { background: #fff;position: fixed; top: 0; left: 0; width: 100%; z-index: 9999; border-bottom: 1px solid #e7e7e7;}
header .back { position: absolute; left: 1.5rem; top: 50%; transform: translateY(-50%); }
header .back img { max-height: 1.5rem;}
header p { padding: 1.5rem 0; text-align: center; font-size: 1.8rem; font-weight: 600;}