Making our site accessible is very important to us. We regularly update and monitor the site for potential issues, if you encounter an issue please email us and we will seek to remedy the issue as soon as possible. While written music notation is not inherently accessible, hence the need for Braille notation for blind or visually impaired students (which we can't do at present), we do our best to make our music notation in both exercises and lessons, our site user interface, videos, and images as accessible of possible. This includes captions on all videos, alt tags on visual elements, maintaining proper contrast ratios, and proper DOM navigation for those with screen readers and those who require keyboard navigation.
When it comes to music notation displayed on the screen, we use SVG images so that images can be scaled without loss of resolution. We are currently in the process of placing written descriptions in aria-labelledby tags on all musical elements used on the notated score, such as clef names, notes locations in relation to staff lines, accidentals, etc. Furthermore, text placed in SVG images is also read as regular text, therefore no text on the site should present an issue with WCAG 2.0 1.4.5 "Images of Text."