- Box Model: profile cards, alerts, buttons instead of generic boxes - Flexbox: navigation bars, headers, toolbars, card layouts - Grid: photo gallery with SVG images, product cards, dashboard layout - Colors: notification alerts, buttons, badges with visible changes - Units/Variables: article width, brand variables, sidebar calc, hero vh - Responsive: feature cards grid instead of numbered divs - Added missing solutions to enable "Show Expected" feature - Fixed barely visible border color change in colors lesson 🤖 Generated with [Claude Code](https://claude.com/claude-code)
- Replace single quotes with <kbd> tags in validation messages - German and English lessons updated for consistent formatting - Move task instruction before description in UI (index.html)
- Shorten verbose lesson titles for better sidebar display - Minor content improvements across lessons