*{box-sizing:border-box;margin:0;padding:0}body{max-width:600px;margin:0 auto;padding:16px;font-family:sans-serif}.auth-container,.todo-container{flex-direction:column;gap:16px;padding-top:40px;display:flex}.auth-container h1{text-align:center}.header{justify-content:space-between;align-items:center;display:flex}form{gap:8px;display:flex}input[type=email],input[type=password],input[type=text]{border:1px solid #ccc;border-radius:4px;flex:1;padding:8px 12px;font-size:16px}button{color:#fff;cursor:pointer;background:#4f46e5;border:none;border-radius:4px;padding:8px 16px;font-size:16px}button:disabled{opacity:.6;cursor:default}button.toggle{color:#4f46e5;text-align:center;background:0 0;padding:0;font-size:14px}.error{color:#dc2626;font-size:14px}ul{flex-direction:column;gap:8px;list-style:none;display:flex}.todo-item{border:1px solid #e5e7eb;border-radius:6px;align-items:center;gap:12px;padding:10px 12px;display:flex}.todo-item span{flex:1;font-size:16px}.todo-item button{background:#ef4444;padding:4px 10px;font-size:14px}.todo-item input[type=checkbox]{cursor:pointer;width:18px;height:18px}