Write maintainable CSS with variables, nesting, mixins, modules, maps, and compiled output.
Lessons
Use null to skip declarations and optional values.
The null Value is easiest to learn by reading the example, changing it, and observing the result.
$brand: #4f46e5;
$space: 1rem;
@mixin card {
border-radius: 8px;
padding: $space;
box-shadow: 0 10px 30px rgb(15 23 42 / .12);
}
.lesson-card {
@include card;
border-color: $brand;
&:hover {
box-shadow: 0 14px 40px rgb(15 23 42 / .18);
}
}Practice the The null Value example in a small scratch file, then explain what changed and why.