CSS Best Practices

Make selector intent explicit, keep controls truthful across states, and verify the rendered result. Apply the relevant checks to the changed behavior; do not turn a local fix into a reset, framework migration, or whole-product audit.

Establish the contract

Inspect the actual styling engine and version, compiler/plugins, browser support targets, design tokens, component markup, and repository validation workflow. Identify which element owns each state and whether the control is native, ARIA-disabled, or driven by a library data attribute. Preserve existing product contracts and visual direction unless the task changes them.

Separate three kinds of rule:

• Standards: cite the applicable specification, criterion, level, and exceptions.
• Team conventions: explicit & and guarded native-button states below.
• Conditional remedies: adopt only after reproducing the relevant failure.