body{font-family:system-ui,-apple-system,Segoe UI,Roboto,"Helvetica Neue",Arial;margin:0;padding:20px;background:#f5f5f5}
.container{max-width:700px;margin:0 auto;background:#fff;padding:20px;border-radius:8px;box-shadow:0 2px 8px rgba(0,0,0,.05)}
h1{margin-top:0}
#addForm{display:flex;gap:8px;margin-bottom:16px}
#addForm input[type=text]{flex:1;padding:8px;border:1px solid #ddd;border-radius:4px}
#addForm button{padding:8px 12px}
#todoList{list-style:none;padding:0;margin:0}
#todoList li{display:flex;align-items:center;gap:12px;padding:8px 0;border-top:1px solid #f0f0f0}
#todoList li:first-child{border-top:0}
.done{text-decoration:line-through;color:#999}
#todoList button{margin-left:auto}