Refreshed course experience on mobile

Question screens, the course introduction, and the completion screen have a cleaner, more consistent look on mobile.

• Consistent question screens — multiple choice, true/false, select all, matching, ordering, image choice, and written answers all share a cleaner look.
• Inline introduction — the course introduction now sits inline in the training flow.
• Redesigned completion screen — clearer pass and fail messaging, a direct link to the certificate, and a simpler way to leave feedback.