Declaring variables
:root {
--color-blue-gray-50: #eceff1;
--color-material-button: #70d6ff;
--color-material-button-7: #68c7ed;
--color-material-button-12: #63bce0;
--color-site-background: #d0f4de;
--color-center: #fff;
}
Using variables
.class_name {
background-color: var(--color-material-button-7);
}