Business cases are commonly adopted into the accounting curricula to promote deep learning. However, in practice, case-based learning is often ineffective without facilitation because of accounting students' strong surface-learning tendencies. This study investigates the case-based learning effect of colour-coded digital annotation (CCDA). CCDA requires students to highlight web-based text using prescribed colours and present case responses as annotated comments. Our findings indicate that students who adopt CCDA achieve greater improvement in case assessments. Consistent with findings in the technology-enhanced literature (TEL), CCDA provides greater benefits for students who engage more with the intervention. However, CCDA's effect on learning outcomes is not correlated with the self-reported learning experience. This study contributes to the literature and practice by presenting a cost-effective intervention to operationalise case-based learning in accounting education.