/* === RESET & APP SHELL === */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
    ::-webkit-scrollbar { display: none; }
    * { scrollbar-width: none; }
    html, body {
      height: 100%; height: 100dvh;
      font-family: var(--font);
      background: var(--bg); color: var(--txt);
      overflow: hidden;
      transition: background .25s, color .25s;
    }
    .app { height: 100%; height: 100dvh; display: flex; flex-direction: column; overflow: hidden; }
    .app-body { flex: 1; display: flex; min-height: 0; overflow: hidden; }
    .main-col { flex: 1; min-width: 0; display: flex; flex-direction: column; overflow: hidden; overflow-y: auto; }