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| Concern | What to inspect | Typical failure |
|---|---|---|
| Core behavior | Cascade Layers and Modern Cascade Control | Layer ordering can make a low-specificity utility beat a high-specificity component if the utility layer has later precedence. That is exactly why layers are powerful. |
| Production test | Real content and constraints | The rule works only for the demo values |
| Maintenance | Scope and override path | A later fix creates another exception |
In production, Layer ordering can make a low-specificity utility beat a high-specificity component if the utility layer has later precedence. That is exactly why layers are powerful. That is the kind of bug that survives visual spot checks because the stylesheet is syntactically valid while the layout contract is wrong.
<style>@layer reset, base, components, utilities;</style><main class="demo">Example content</main>
A good CSS change narrows the problem. Use layers to define architecture, not as a replacement for naming. Specificity still matters inside a layer. This keeps the rule understandable when content, theme, or viewport conditions change later.
In production, Layer ordering can make a low-specificity utility beat a high-specificity component if the utility layer has later precedence. That is exactly why layers are powerful. That is the kind of bug that survives visual spot checks because the stylesheet is syntactically valid while the layout contract is wrong.
<style>@layer components { .card { padding:1rem; } }</style><main class="card">Example content</main>
Engineering judgment: Use layers to define architecture, not as a replacement for naming. Specificity still matters inside a layer.
<style>@layer { .legacy { all:unset; } }</style><main class="legacy">Example content</main>
Anonymous layer is useful here because it demonstrates cascade layers and modern cascade control under a concrete input rather than as an abstract property list.
<style>@import url("theme.css") layer(theme);</style><main class="demo">Example content</main>
Import into layer is useful here because it demonstrates cascade layers and modern cascade control under a concrete input rather than as an abstract property list.
Finish the lesson once you have worked through the material. This awards ★ 30 XP.