I'm getting weird characters on the Amatic SC Google font

We're aware of this issue and we've contacted the Google fonts team who assured us they will fix it. The easiest fix for now is to switch the font to the unbold version.

Copy and paste this CSS in your Appearance > Customize > Custom CSS Block (or into the style.css if you are using the Ghost theme).

.site-title, h1, h2, h3, h4, h5, h6, .meta, .more-link, .share-overlay, .content-aside, blockquote, .btn, button, .filter, .post-meta, .btn, button, .button, input[type="submit"], header.header nav, .hero, #comments .url, .form-submit input[type="submit"], .widget h4 { font-weight: 400; }

Or if you just want to effect the titles in the posts...

h1, h2, h3, h4, h5, h6 { font-weight: 400; }