It's the theme css, it's setting a left margin (margin-left: 2.8em ) on the li item, and the calendar uses li for the button structure, and unfortunately does not set it's own css for li.
From your theme css:
li {
margin-bottom: 0.5em;
margin-left: 2.8em; <<< THIS is the problem ****
padding: 0;
}
The following css will reset the margin for the buttons only. Just add it to a css file that is loaded after the theme css (or follow the theme's instructions below):
ai1ec-pagination li {
margin-left: 0;
}
The following is from your theme css file and tells you where/how to add a custom css file.
!!!!!!!!!! DO NOT EDIT THIS FILE !!!!!!!!!!
If you need to make changes to this theme, create a new stylesheet in the wp-content folder then go to the 'Wordpress Admin > Settings > Adventure Journal' and add your new stylesheet under the 'Custom Stylesheet' section. This will prevent your changes from being overwritten when new versions of this theme is released.
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!