nav { position: fixed; bottom:0; width: 100%; background: #f1f2f6; z-index: 9999;}
nav ul { display: flex; justify-content: space-around; }
nav ul li { width: 20%; text-align: center;}
nav ul li a { display: block; font-weight: 500; padding-top: 4rem; padding-bottom: 1rem; color: #b1bbcd; font-size: 1.6rem; position: relative;}
nav ul li a:before {background-size: cover; position: absolute; width: 2.5rem; height: 2.5rem; left: 50%; top: 0.7rem; transform: translateX(-50%);}
nav ul li:nth-child(1) a:before { content: ''; background-image: url(../img/menu1_off.png);}
nav ul li:nth-child(2) a:before { content: ''; background-image: url(../img/menu2_off.png);}
nav ul li:nth-child(3) a:before { content: ''; background-image: url(../img/menu3_off.png);}
nav ul li.on a { color: #30415e;}
nav ul li.on:nth-child(1) a:before { background-image: url(../img/menu1.png) ;}
nav ul li.on:nth-child(2) a:before { background-image: url(../img/menu2.png) ;}
nav ul li.on:nth-child(3) a:before { background-image: url(../img/menu3.png) ;}


#wrap { padding-bottom: 6.5rem;}

header { border-bottom: 1px solid #ddd; display: flex; align-items: center; justify-content: center; padding: 1.5rem; position: relative;}
header a.home_btn img { width: 12rem;}
header a.prev_btn img { width: 1.2rem; position: absolute; top: 50%; left: 1.5rem; transform: translateY(-50%);}
header p { font-size: 1.8rem; font-weight: 500;}

main { min-height: calc(100vh - 13rem); padding-bottom:1.5rem;}