/* Calculator App UI - making it look fancy and proper */
    #calc-display {
      background: transparent;
      border-radius: var(--radius); /* smooth display */
      padding: 20px 10px;
      font-size: 42px;
      font-weight: 300;
      text-align: right;
      margin-bottom: 15px;
      color: var(--text);
      font-family: var(--font);
      word-break: break-all;
      line-height: 1;
    }
    #calc-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 12px;
    }
    #calc-grid button {
      background: rgba(255, 255, 255, 0.15);
      border: 1px solid rgba(255, 255, 255, 0.1);
      padding: 18px 0;
      border-radius: 50%; /* smooth circular buttons */
      font-size: 20px;
      font-weight: 500;
      color: var(--text);
      cursor: pointer;
      transition: all 0.2s cubic-bezier(0.2, 0.8, 0.2, 1);
      aspect-ratio: 1/1;
      display: flex;
      align-items: center;
      justify-content: center;
      backdrop-filter: blur(10px);
    }
    .dark-theme #calc-grid button { background: rgba(0, 0, 0, 0.2); border-color: rgba(0,0,0,0.1); }
    #calc-grid button:hover { background: rgba(255, 255, 255, 0.3); transform: scale(0.92); }
    .dark-theme #calc-grid button:hover { background: rgba(255, 255, 255, 0.1); }
    #calc-grid button:active { transform: scale(0.85); }
    
    /* speical buttons */
    #calc-grid button.calc-op { background: #FF9F0A; color: white; border: none; font-size: 24px; font-weight: 600; }
    #calc-grid button.calc-op:hover { background: #FFB340; }
    #calc-grid button.calc-top { background: rgba(200, 200, 200, 0.3); color: var(--text); font-weight: 600; }
    #calc-grid button.calc-zero { grid-column: span 2; aspect-ratio: auto; border-radius: 40px; justify-content: flex-start; padding-left: 30px; }

    /* iframe apps */
    .app-iframe { width: 100%; height: 100%; border: none; border-radius: 0 0 var(--radius) var(--radius); background: var(--bg); flex: 1; }

    body.dark-theme .app-iframe { background: var(--bg); }
    body.dark-theme #settings-name-input { background: rgba(255,255,255,0.06); color: var(--text); }
    body.dark-theme .folder-app:hover { background: rgba(255,255,255,0.06); }

    /* Folder Apps inside the Games/Tools groups */
    .folder-app {
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      width: 76px;
      cursor: pointer;
      padding: 10px;
      border-radius: var(--radius);
      transition: transform 0.15s cubic-bezier(0.2, 0.8, 0.2, 1), background 0.15s;
    }
    .folder-app:hover {
      background: rgba(128, 128, 128, 0.1);
      transform: scale(1.08); /* slight pop effect */
    }
    .folder-icon {
      width: 54px;
      height: 54px;
      border-radius: var(--radius);
      display: flex;
      align-items: center;
      justify-content: center;
      font-size: 28px;
      box-shadow: var(--shadow);
      margin-bottom: 10px;
    }
    .folder-name {
      font-size: 12px;
      color: var(--text);
      font-weight: 500;
      text-align: center;
      line-height: 1.2;
    }