Hi Maeda,
Let me check if this is working. As a heads up, I would also recommend using V2, which you can find here!
https://beta.developers.miro.com/docs/ui_boardui
Keep in mind, that you are not able to customize the width in V2 yet.
Can I ask what you are trying to do that needs a wider viewport?
@Addison Schultz
Thank you for your answer! I will also try V2.
On my laptop, the width of the leftsidebar is wide and the space for working on the board is small, so I want to narrow it.
Right now, the panels are set at a certain size and cannot be changed, but this is a great idea for a future improvement!
We also do have a public roadmap that you can submit your own ideas to. If you’re interested, feel free to submit it here!
https://beta.developers.miro.com/page/roadmap