weseek__growi/packages/presentation/src/client/components/Presentation.global.scss

:root[data-bs-theme='light'] {
  .reveal-viewport {
    // adjust marp default theme
    background-color: #fff;
  }
}

:root[data-bs-theme='dark'] {
  .reveal-viewport {
    // adjust marp default theme
    background-color: #0d1117;
  }
}