:root{--bg:#121212;--card:#1e1e1e;--text:#fff;--muted:#2b2b2b;--accent:#4cafef}*{box-sizing:border-box}body{margin:0;background:var(--bg);color:var(--text);font-family:system-ui,Arial,sans-serif}.container{max-width:900px;margin:32px auto;padding:0 16px}.card{background:var(--card);border:1px solid var(--muted);border-radius:16px;padding:16px;margin:12px 0}.row{display:flex;flex-wrap:wrap;gap:8px;margin:8px 0}input,button{padding:10px;border-radius:10px;border:1px solid var(--muted);background:#111;color:#fff}button{cursor:pointer;background:var(--accent);border:none}ul{list-style:none;padding:0;margin:0}li{display:flex;justify-content:space-between;align-items:center;background:#1b1b1b;border:1px solid var(--muted);border-radius:12px;margin:8px 0;padding:10px}.done{opacity:.6;text-decoration:line-through}.small{font-size:.9rem}.error{color:#ff6b6b;margin:6px 0}.success{color:#61d36e;margin:6px 0}.muted{opacity:.8}button[disabled]{opacity:.6;cursor:not-allowed}.inline{display:inline-block;margin-left:8px;font-size:.9rem}input.invalid{border-color:#ff6b6b;outline:1px solid #ff6b6b55}