Check out example codes for "scss variables". It will help you in understanding the concepts better.

Code Example 1

$base-color: #c6538c;

Code Example 2

$base-color: #c6538c;
$border-dark: rgba($base-color, 0.88);

.alert {
  border: 1px solid $border-dark;
}

Code Example 3

$variable: 1;

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