body{margin:0;font-family:system-ui,sans-serif;background:#fff}main{max-width:420px;margin:40px auto;padding:20px}input{width:90%;padding:10px;margin-bottom:10px;font-size:1em}button{padding:10px 14px;cursor:pointer;font-size:1em}.done{text-decoration:line-through;color:#888}.streak{margin-bottom:20px;font-size:1.1em}footer{margin-top:40px;font-size:.85em;color:#777}