On desktops the comment submit button is misaligned

Prerequisites

[ ] Can you reproduce the behavior you wish to address with all plugins except Pressbooks deactivated?
[ ] Are you running the latest version of Pressbooks, the latest version of Aldine, and the latest version of WordPress?
[ ] Are you experiencing the issue while using Aldine as your network's root theme?
[ ] Did you perform a cursory search to see if your bug or enhancement is already listed?

Description

comment_submitt_button

System Information

Book Info

Book ID: 16 Book URL: http://localhost/wordpress/pwlo00117r4/ Book Privacy: Public

Browser

Platform: OS X Browser Name: Chrome Browser Version: 63.0.3239.132 User Agent String: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_13_3) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/63.0.3239.132 Safari/537.36

WordPress Configuration

Network URL: http://localhost/wordpress/ Network Type: Subdirectory Version: 4.9.4 Language: en_US WP_ENV: developer WP_DEBUG: Enabled Memory Limit: 64M

Pressbooks Configuration

Version: 4.5.0 Book Theme: McLuhan Book Theme Version: 2.0.0-beta.2 Root Theme: Aldine Root Theme Version: 1.0.0-alpha.6

Pressbooks Dependencies

Epubcheck: Installed Kindlegen: Installed xmllint: Installed PrinceXML: Installed Saxon-HE: Installed

Must-Use Plugins

hm-autoloader.php: n/a

Network Active Plugins

Hypothesis: 0.5.0 Pressbooks: 5.0.0-dev

Book Active Plugins

Inactive Plugins

Server Configuration

PHP Version: 7.1.12 MySQL Version: 5.6.38 Webserver Info: Apache/2.2.34 (Unix) mod_wsgi/3.5 Python/2.7.13 PHP/7.1.12 mod_ssl/2.2.34 OpenSSL/1.0.2j DAV/2 mod_fastcgi/2.4.6 mod_perl/2.0.9 Perl/v5.24.0

PHP Configuration

Safe Mode: Disabled Memory Limit: 256M Upload Max Size: 32M Post Max Size: 32M Upload Max Filesize: 32M Time Limit: 30 Max Input Vars: 1000 URL-aware fopen: On (1) Display Errors: On (1)

PHP Extensions

OPcache: Disabled XDebug: Disabled cURL: Supported cURL Version: 7.52.1 imagick: Not Installed xsl: Installed

pressbooks / pressbooks-aldine