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Get Started Free →Use when reviewing rendered HTML, interactive components, or design-system patterns related to Use exactly one main landmark. Check native semantics first, then inspect keyboard behavior, focus flow, accessible names, and screen-reader output where relevant.
.claude/skills/thedaviddias-landmark-one-main/SKILL.md| Test case | Without → With | Effect | Δ tokens | Δ turns |
|---|---|---|---|---|
| case-05 | ✓→✗ | ▼ Worse | -14% | 0% |
| case-01 | ✓→✓ | ＝ Same ✓ | -10% | 0% |
| case-02 | ✓→✓ | ＝ Same ✓ | 8% | 0% |
| case-03 | ✓→✓ | ＝ Same ✓ | -4% | 0% |
| case-04 | ✓→✓ | ＝ Same ✓ | 20% | 0% |
A single main landmark allows keyboard and screen reader users to jump directly to the primary content of the page, bypassing repetitive navigation.
<main> elementrole='main'Count the number of <main> elements or elements with role='main' on the page to ensure there is exactly one.
Combine multiple main content areas into a single <main> element or remove the 'role=main' attribute from extra containers.
Explain how the main landmark acts as a primary navigation target for assistive technologies, and why multiple main areas cause confusion.
Review the rendered markup and interactive states that affect Use exactly one main landmark. Flag exact elements, roles, labels, focus behavior, or keyboard interactions that violate the rule, and note how to verify the fix with browser accessibility tooling or assistive tech.
For full implementation details, code examples, and framework-specific guidance, see references/rule.md.
Rule page: https://frontendchecklist.io/en/rules/accessibility/landmark-one-main
| Case | Status | Duration (ms) | Turns | Tokens | Tool calls | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Without | With | Δ | Without | With | Δ | Without | With | Δ | Without | With | Δ | ||
case-01 | pass→pass | 17,372 | 6,890 | -60% | 1 | 1 | 0% | 1,870 | 1,675 | -10% | 0 | 0 | — |
case-02 | pass→pass | 13,908 | 15,159 | +9% | 1 | 1 | 0% | 1,233 | 1,331 | +8% | 0 | 0 | — |
case-03 | pass→pass | 16,710 | 17,256 | +3% | 1 | 1 | 0% | 1,731 | 1,660 | -4% | 0 | 0 | — |
case-04 | pass→pass | 9,684 | 9,150 | -6% | 1 | 1 | 0% | 1,591 | 1,903 | +20% | 0 | 0 | — |
case-05 | pass→fail | 12,167 | 9,854 | -19% | 1 | 1 | 0% | 2,068 | 1,783 | -14% | 0 | 0 | — |
case-06 | pass→pass | 10,933 | 9,839 | -10% | 1 | 1 | 0% | 1,850 | 1,852 | +0% | 0 | 0 | — |
case-07 | pass→pass | 13,753 | 5,632 | -59% | 1 | 1 | 0% | 1,981 | 1,084 | -45% | 0 | 0 | — |
case-13 | pass→pass | 15,220 | 11,638 | -24% | 1 | 1 | 0% | 2,251 | 2,001 | -11% | 0 | 0 | — |
case-08 | pass→pass | 9,348 | 11,759 | +26% | 1 | 1 | 0% | 1,605 | 2,146 | +34% | 0 | 0 | — |
case-09 | pass→pass | 7,875 | 5,686 | -28% | 1 | 1 | 0% | 1,193 | 1,205 | +1% | 0 | 0 | — |
case-10 | pass→pass | 9,939 | 7,875 | -21% | 1 | 1 | 0% | 1,681 | 1,509 | -10% | 0 | 0 | — |
case-11 | pass→pass | 9,800 | 9,575 | -2% | 1 | 1 | 0% | 1,382 | 1,674 | +21% | 0 | 0 | — |
case-12 | pass→pass | 13,010 | 12,513 | -4% | 1 | 1 | 0% | 2,370 | 2,240 | -5% | 0 | 0 | — |
case-14 | pass→pass | 13,727 | 10,507 | -23% | 1 | 1 | 0% | 1,973 | 1,903 | -4% | 0 | 0 | — |
case-15 | pass→pass | 9,510 | 5,535 | -42% | 1 | 1 | 0% | 1,342 | 958 | -29% | 0 | 0 | — |
case-16 | pass→pass | 8,804 | 8,277 | -6% | 1 | 1 | 0% | 1,322 | 1,444 | +9% | 0 | 0 | — |
case-17 | pass→pass | 8,935 | 6,576 | -26% | 1 | 1 | 0% | 1,483 | 1,352 | -9% | 0 | 0 | — |
case-18 | pass→pass | 10,079 | 8,813 | -13% | 1 | 1 | 0% | 1,816 | 1,595 | -12% | 0 | 0 | — |
case-19 | pass→pass | 13,269 | 10,258 | -23% | 1 | 1 | 0% | 1,856 | 1,651 | -11% | 0 | 0 | — |
case-20 | pass→pass | 15,029 | 9,826 | -35% | 1 | 1 | 0% | 2,019 | 1,572 | -22% | 0 | 0 | — |
case-21 | pass→pass | 13,740 | 9,945 | -28% | 1 | 1 | 0% | 2,085 | 1,689 | -19% | 0 | 0 | — |
case-22 | pass→pass | 13,458 | 8,514 | -37% | 1 | 1 | 0% | 1,917 | 1,400 | -27% | 0 | 0 | — |
DecimalAI ran this skill against gemini-3.6-flash twice over the same eval suite — once with the skill loaded and once without — and compared the two runs case by case. 22 cases were attempted. The headline lift of -100 percentage points is the difference between those two pass rates over the 22 comparable cases. 1 case got worse with the skill loaded, and it is included in that figure.
Other measured skills in the registry, with their headline benchmark lift.