Observation Details
Keyboard focus of Magenta button changes background color. Difference between default and focused state does not meet minimum contrast ratio (3:1). Instead, the difference is barely visible at 1.1:1.
"Jetzt buchen / Jetzt dazubuchen" buttons in tariff card and also in the following dialog window.
Remediation Notes
Ensure enough contrast (3:1) between different button states (default, focused, active, ...).