body {font-family: Arial; margin:0; background:#f5f7fb;}
.nav {position:sticky;top:0;background:#fff;display:flex;overflow-x:auto;padding:10px;gap:8px;border-bottom:1px solid #ddd;}
.nav button{padding:10px 14px;border:none;background:#e3e7f0;border-radius:20px;}
.tab{display:none;padding:15px;}
.tab.active{display:block;}
.add{margin-top:10px;padding:12px;background:#4CAF50;color:white;border:none;border-radius:10px;width:100%;}