.memory-wrapper {
      max-width: 960px;
      margin: 0 auto 40px;
      display: grid;
      gap: 20px;
    }
    .memory-controls {
      display: flex;
      flex-wrap: wrap;
      gap: 12px;
      align-items: center;
      justify-content: space-between;
      background: #fff;
      border-radius: 12px;
      box-shadow: 0 4px 16px rgba(15, 23, 42, 0.08);
      padding: 16px 20px;
    }
    .memory-controls .buttons {
      display: flex;
      gap: 10px;
      flex-wrap: wrap;
      align-items: center;
    }
    .memory-mode {
      display: flex;
      align-items: center;
      gap: 12px;
      background: #eff6ff;
      border-radius: 999px;
      padding: 6px 12px;
    }
    .memory-mode label {
      display: flex;
      align-items: center;
      gap: 6px;
      font-size: 14px;
      color: #0f172a;
      cursor: pointer;
    }
    .memory-deck {
      display: flex;
      align-items: center;
      gap: 8px;
      background: #f8fafc;
      border-radius: 12px;
      padding: 6px 12px;
      font-size: 14px;
      color: #0f172a;
    }
    .memory-deck select {
      border: 1px solid #cbd5e1;
      border-radius: 8px;
      padding: 6px 10px;
      font-size: 14px;
      background: #fff;
      color: #0f172a;
    }
    .memory-buttons {
      display: flex;
      gap: 10px;
      flex-wrap: wrap;
    }
    .memory-controls button {
      background: #2563eb;
      color: #fff;
      border: none;
      border-radius: 10px;
      padding: 10px 18px;
      font-size: 15px;
      cursor: pointer;
      transition: transform 0.1s ease, box-shadow 0.1s ease;
    }
    .memory-controls button:active {
      transform: scale(0.97);
      box-shadow: inset 0 2px 6px rgba(0,0,0,0.15);
    }
    .memory-toggle {
      display: flex;
      align-items: center;
      gap: 8px;
      font-size: 14px;
      color: #0f172a;
    }
    .memory-stats {
      display: flex;
      gap: 16px;
      flex-wrap: wrap;
      font-size: 14px;
      color: #0f172a;
    }
    .memory-board {
      background: #fff;
      border-radius: 12px;
      box-shadow: 0 4px 16px rgba(15, 23, 42, 0.08);
      padding: 20px;
    }
    .memory-grid {
      display: grid;
      grid-template-columns: repeat(4, minmax(64px, 1fr));
      gap: 12px;
    }
    .memory-card {
      position: relative;
      width: 100%;
      padding-bottom: 120%; /* maintain aspect ratio */
      perspective: 900px;
    }
    .memory-card button {
      position: absolute;
      inset: 0;
      width: 100%;
      height: 100%;
      border: none;
      border-radius: 12px;
      background: transparent;
      cursor: pointer;
      transform-style: preserve-3d;
      transition: transform 0.5s ease;
    }
    .memory-card button.flipped {
      transform: rotateY(180deg);
      cursor: default;
    }
    .memory-face {
      position: absolute;
      inset: 0;
      border-radius: 12px;
      backface-visibility: hidden;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      padding: 12px;
      color: #fff;
      font-weight: 600;
    }
    .memory-face.back {
      background: linear-gradient(135deg, #2563eb, #4f46e5);
    }
    .memory-face.front {
      transform: rotateY(180deg);
      background: #f8fafc;
      border: 2px solid rgba(148, 163, 184, 0.45);
      color: #0f172a;
      font-size: 15px;
      text-align: center;
      gap: 6px;
    }
    .memory-face.front span.family {
      font-size: 12px;
      color: #475569;
      font-weight: 500;
    }
    .memory-message {
      min-height: 24px;
      font-size: 15px;
      font-weight: 600;
      color: #2563eb;
      padding: 0 2px;
    }
    @media (max-width: 1024px) {
      .memory-wrapper {
        padding: 0 16px;
      }
      .memory-controls {
        flex-direction: column;
        align-items: stretch;
        gap: 16px;
      }
      .memory-controls .buttons {
        width: 100%;
        justify-content: space-between;
      }
      .memory-mode,
      .memory-deck,
      .memory-buttons {
        width: 100%;
        justify-content: space-between;
      }
      .memory-stats {
        width: 100%;
        justify-content: space-between;
      }
      .memory-board {
        padding: 16px;
      }
      .memory-grid {
        grid-template-columns: repeat(3, minmax(0, 1fr));
        gap: 14px;
      }
      .memory-card {
        padding-bottom: 110%;
      }
    }
    @media (max-width: 640px) {
      .memory-grid {
        grid-template-columns: repeat(3, 1fr);
      }
      .memory-controls {
        flex-direction: column;
        align-items: stretch;
      }
      .memory-controls .buttons {
        width: 100%;
        justify-content: space-between;
        gap: 12px;
      }
      .memory-mode {
        width: 100%;
        justify-content: space-between;
      }
      .memory-deck {
        width: 100%;
        justify-content: space-between;
      }
      .memory-buttons {
        width: 100%;
        justify-content: space-between;
      }
      .memory-stats {
        flex-direction: column;
        align-items: flex-start;
        gap: 8px;
      }
    }