:root{
  --bg:#f5f7fb;
  --card:#fff;
  --text:#1f2937;
  --muted:#6b7280;
  --primary:#0ea5e9;
  --primary-hover:#0284c7;
  --danger:#ef4444;
  --border:#e5e7eb;
}

*{ box-sizing: border-box; }
body{ margin:0; font-family:system-ui,-apple-system,Segoe UI,Roboto,Arial; background:var(--bg); color:var(--text); }

.container{ max-width:820px; margin:48px auto; background:var(--card); border-radius:14px; padding:24px; box-shadow:0 8px 28px rgba(0,0,0,.06); }

.hero h1{ margin:0 0 6px; text-align:center; }
.hero .sub{ margin:0 0 16px; text-align:center; color:var(--muted); }

.msg{ margin:10px 0 14px; padding:10px 12px; border-radius:10px; border:1px solid #ffd0cf; background:#fff2f2; color:#7a0b0b; }

.tabs{ display:flex; gap:8px; flex-wrap:wrap; margin-bottom:16px; }
.tab{ padding:8px 12px; border:1px solid var(--border); background:#f3f4f6; border-radius:10px; cursor:pointer; }
.tab.active{ background:#e0f2fe; border-color:#bae6fd; color:#075985; }

.panel{ display:none; }
.panel.active{ display:block; }

.form{ display:flex; gap:8px; margin-bottom:10px; }
.form input{ flex:1; padding:10px 12px; border:1px solid var(--border); border-radius:10px; font-size:15px; }

.row{ display:flex; align-items:center; justify-content:space-between; gap:10px; margin-bottom:10px; }
.muted{ color:var(--muted); font-size:12px; }

.btn{ padding:10px 14px; border:none; border-radius:10px; background:#f3f4f6; cursor:pointer; }
.btn.primary{ background:var(--primary); color:#fff; }
.btn.primary:hover{ background:var(--primary-hover); }
.btn.danger{ background:var(--danger); color:#fff; }
.btn:disabled{ opacity:.6; cursor:not-allowed; }

.list{ list-style:none; margin:0; padding:0; }
.item{ display:flex; align-items:center; gap:12px; border:1px solid var(--border); border-radius:12px; padding:12px; margin-bottom:8px; }
.item .title{ flex:1; }
.item.completed .title{ text-decoration:line-through; color:var(--muted); }

.code{ background:#0b1220; color:#d1e1ff; padding:12px; border-radius:10px; overflow:auto; min-height:48px; }
.card{ border:1px solid var(--border); border-radius:12px; padding:12px; }

.switch{ display:flex; align-items:center; gap:8px; }