#taguzu-board {
      margin: 30px auto;
      border-collapse: collapse;
    }

    #taguzu-board td {
      width: 50px;
      height: 50px;
      text-align: center;
      vertical-align: middle;
      border: 1.5px solid #555;
      font-size: 1.4em;
      background: #fff;
      position: relative;
    }

    #taguzu-board input {
      width: 100%;
      height: 100%;
      border: none;
      text-align: center;
      font-size: 1.2em;
      background: transparent;
    }

    #taguzu-board .fixed {
      background: #e0e0e0;
      font-weight: bold;
    }

    #taguzu-board .error {
      background: #EF9A9A !important;
    }

    #controls {
      margin: 20px auto;
      text-align: center;
    }

    .taguzu {
      color: #1c657d;
      font-family: 'Fredoka', sans-serif;
    }

    .taguzu .board {
      color: #616161;

    }

    .taguzu .msg {
      color: #b00;
    }


    :root {
      --cell-size: 44px;
      --gap: 6px;
      --fixed-bg: #f3f4f6;
      --accent: #2563eb;
      --accent-weak: #c7d2fe;
      --error: #ef4444;
      --ok: #16a34a;
      --hint: #f59e0b;
      --text: #111827;
    }
    * { box-sizing: border-box; }
    body {
      font-family: system-ui, -apple-system, Segoe UI, Roboto, Ubuntu, Cantarell, Noto Sans, Helvetica, Arial, "Apple Color Emoji", "Segoe UI Emoji";
      margin: 0;
      padding: 24px;
      color: var(--text);
      background: #ffffff;
      line-height: 1.4;
    }
    header {
      margin-bottom: 16px;
    }
    h1 {
      font-size: 1.6rem;
      margin: 0 0 4px 0;
    }
    .meta {
      font-size: .9rem;
      color: #6b7280;
      margin-bottom: 12px;
    }
    .board-wrap {
      display: grid;
      grid-template-columns: 1fr;
      gap: 16px;
      align-items: start;
    }
    .board {
      display: grid;
      gap: var(--gap);
      justify-content: start;
      align-items: start;
      background: #fff;
      padding: 8px;
      border-radius: 12px;
      box-shadow: 0 1px 2px rgba(0,0,0,.06), 0 8px 24px rgba(0,0,0,.06);
      width: fit-content;
      max-width: 100%;
      overflow: auto;
      margin:auto;
    }
    .cell {
      width: var(--cell-size);
      height: var(--cell-size);
      border: 1px solid #e5e7eb;
      border-radius: 10px;
      display: grid;
      place-items: center;
      font-weight: 700;
      font-size: 1.1rem;
      cursor: pointer;
      user-select: none;
      transition: transform .06s ease, background-color .2s ease, border-color .2s ease;
      background: #fff;
    }
    .cell:hover { transform: translateY(-1px); }
    .cell.fixed {
      background: var(--fixed-bg);
      cursor: default;
    }
    .cell.error {
      outline: 2px solid var(--error);
      outline-offset: -2px;
      background: #fee2e2;
    }
    .cell.hint {
      outline: 2px dashed var(--hint);
      outline-offset: -2px;
      animation: pulse 1s ease-in-out 3;
    }
    @keyframes pulse {
      0% { background: #fff7ed; }
      50% { background: #ffedd5; }
      100% { background: #fff7ed; }
    }
    .toolbar {
      display: flex;
      flex-wrap: wrap;
      gap: 10px;
      margin:auto;
    }
    .toolbar button {
      border: 1px solid #e5e7eb;
      background: #fff;
      padding: 10px 14px;
      border-radius: 10px;
      font-weight: 600;
      cursor: pointer;
      transition: background .15s ease, border-color .15s ease, transform .06s ease;
    }
    .toolbar button:hover {
      background: #f8fafc;
      border-color: #cbd5e1;
      transform: translateY(-1px);
    }
    .toolbar button.primary {
      background: var(--accent);
      color: white;
      border-color: transparent;
    }
    .toolbar button.primary:hover { background: #1d4ed8; }
    .toolbar button.warn {
      background: #fff7ed;
      border-color: #fed7aa;
    }
    .toolbar button.danger {
      background: #fee2e2;
      border-color: #fecaca;
    }
    .status {
      margin-top: 6px;
      font-size: .98rem;
      min-height: 24px;
    }
    .status .ok { color: var(--ok); font-weight: 700; }
    .status .err { color: var(--error); font-weight: 700; }
    .legend {
      font-size: .92rem;
      color: #374151;
    }
    .legend code { background: #f3f4f6; padding: 0 6px; border-radius: 6px; }
    @media (max-width: 640px) {
      :root { --cell-size: 40px; --gap: 5px; }
    }