Write maintainable CSS with variables, nesting, mixins, modules, maps, and compiled output.
Lessons
Let modules be configured while keeping safe defaults.
Default Values with !default is easiest to learn by reading the example, changing it, and observing the result.
// _button.scss
$radius: 4px !default; // only used if not already set
.button { border-radius: $radius; }
// Override when importing the module
// @use 'button' with ($radius: 12px);Practice the Default Values with !default example in a small scratch file, then explain what changed and why.