CSS @layer 样式层级与冲突治理实践

概览`@layer` 可显式控制样式的级联顺序。分层架构能在大规模 CSS 中减少覆盖、提升可维护性，与 `@scope`、设计令牌共同构建稳定样式系统。层级定义@layer reset, base, components, utilities;

@layer reset {

*, *::before, *::after { box-sizing: border-box; }

}

@layer base {

html { color-scheme: light dark; }

body { margin: 0; font: 1rem/1.6 system-ui; }

}

@layer components {

.btn { padding: .5rem .75rem; border-radius: 8px; }

}

@layer utilities {

.mt-2 { margin-top: .5rem; }

.text-muted { color: #666; }

}

层内与层间策略@layer components {

.card { padding: 1rem; border: 1px solid #eee; }

}

@layer utilities {

.border-none { border: none; }

}

治理要点严格限制跨层覆盖，优先在同层内调整。公共样式放在 base，组件样式放在 components，工具类在 utilities。与 `@scope` 组合在组件内限定影响范围。验证与指标浏览器：Chrome 120+、Safari 17+、Firefox 120+大型页面样式冲突显著减少，覆盖链条清晰