You kept the class my colleague mentioned for the second button, but my another colleague stated that you should remove that from the suggestion he gave.
Anyway, I removed that class and added a simple margin for the buttons in the style option:
The result is:
For the second question you added a Center Class to the button:
That class has a width of 50% so it is natural that it will be that big:
I removed that class and the result is:
I strongly suggest that you get yourself more familiar with simple CSS coding as you will need that in the future:
https://www.w3schools.com/css/
Also, I suggest that you learn how to make use of the Chrome browser to find the correct selectors of your CSS code:
Kindly open up new threads for additional questions as it will help us to focus on each issue and give you a better support which you deserve. Having a long threads makes the maintaining job harder and also it will be harder for the other customers to find the correct information if they have similar issues. You are always welcomed to reply to this thread to follow up the same question.
Thank you.