/* ── Outer combined container ── */
  .game-container {
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 20px;
    border: 2px solid #2a2a2a;
    border-radius: 0;
    overflow: hidden;
    height: 500px;
    width:730px;
  }

  /* ── Info sidebar ── */
  .sidebar {
    background: #f0f0f0;
    border-right: 2px solid #2a2a2a;
    padding: 20px 16px;
    width: 180px;
    flex-shrink: 0;
    display: flex;
    flex-direction: column;
    gap: 0;
    height: 500px;
  }

/*  h1 {
    font-family: 'Playfair Display', serif;
    font-size: 1.15rem;
    color: #c0001a;
    margin-bottom: 16px;
    letter-spacing: 0.02em;
  }  */

  .level-row {
    display: flex;
    align-items: center;
    gap: 8px;
    margin-bottom: 16px;
  }

  .level-row label {
    font-size: 0.85rem;
    color: #444;
    white-space: nowrap;
  }

  .level-row select {
    background: #fff;
    color: #222;
    border: 1px solid #999;
    border-radius: 4px;
    padding: 3px 6px;
    font-size: 0.95rem;
    cursor: pointer;
    flex: 1;
  }

  .info-block {
    background: #fff;
    border: 1px solid #ccc;
    border-radius: 4px;
    padding: 10px 12px;
    margin-bottom: 14px;
    font-size: 0.85rem;
    line-height: 2;
  }

  .info-block .label { color: black; }
  .info-block .value { color: #111; font-weight: 600; }

  .moves-history {
    font-size: 0.85rem;
    color: #b06000;
    letter-spacing: 0.1em;
    margin: 4px 0 0;
    word-break: break-all;
  }

  .result-msg {
    font-family: 'Playfair Display', serif;
    font-size: 1.15rem; //0.95rem;
    font-weight: 700;
    margin: 10px 0 4px;
    display: none;
    line-height: 1.3;
  }
  .result-msg.win   { color: #1a8a3a; }
  .result-msg.close { color: #b06000; }
  .result-msg.border { color: #555555; }

  .btn {
    color: white;
    border: none;
    border-radius: 4px;
    padding: 8px 12px;
    font-size: 1rem; // 0.72rem;
    cursor: pointer;
    margin-top: 8px;
    width: 100%;
    transition: background 0.2s;
  }
  .btn-new   { background: #0B6623; } //#c0001a; }
  .btn-new:hover   { background: #900013; }
  .btn-retry { background: #555; }
  .btn-retry:hover { background: #333; }

  /* ── Game canvas area ── */
  .game-area {
    background: #ffffff;
    width: 550px;
    height: 500px;
    flex-shrink: 0;
    position: relative;
    overflow: hidden;
  }

  /* Canvas is drawn at 700×680 internally, CSS-scaled to fit 550×500 */
  .canvas-wrapper {
    position: absolute;
    top: 0; left: 0;
    width: 550px;
    height: 500px;
  }

  #gameCanvas {
    display: block;
    /* Scale the 700×680 canvas down to 550×500 */
    width: 550px;
    height: 500px;
  }

  /* ── Vertex buttons overlaid on canvas ── */
  .vbtn {
    position: absolute;
    background: #2a2a2a;
    color: #ffffff;
    border: 2px solid #555;
    border-radius: 50%;
    width: 26px;
    height: 26px;
    font-family: 'Playfair Display', serif;
    font-size: 1rem;
    font-weight: 700;
    cursor: pointer;
    transition: all 0.15s;
    display: flex;
    align-items: center;
    justify-content: center;
    transform: translate(-50%, -50%);
    z-index: 10;
  }
  .vbtn:hover {
    background: #c0001a;
    border-color: #c0001a;
    transform: translate(-50%, -50%) scale(1.15);
    box-shadow: 0 0 10px rgba(192,0,26,0.4);
  }
  .vbtn:active  { transform: translate(-50%, -50%) scale(0.93); }
  .vbtn:disabled {
    opacity: 0.35;
    cursor: not-allowed;
    transform: translate(-50%, -50%);
  }