Why is this button so long in a mobile browser?

Hi,

If you want to change the size of that button you’ll need to add a custom css in Newspaper>Theme panel>Custom code>Advance css in phone
https://www.screencast.com/t/hBOAKujif
.comments .comment-form .submit {
width: 60%;
}

Normally that button should look like this, but you have set to all p { text-indent: 2.1em; } so if you want to look like this you can set this code
.comments #respond p {
text-indent: 0;
}
in Newspaper>Theme panel>Custom code>Advance css in phone

Thank you!