few suggestions

[vujovicigor]

Great work guys, milligram is fantastic.
Here is few suggestions:

• when select element is open, default browser color is used, it can be fixed:

option:checked
    background: linear-gradient($color-primary, $color-primary)

• onclick effect:

.button:active, button:active, input[type="button"]:active, input[type="submit"]:active, input[type="reset"]:active
    transition: none
    opacity: 0.7

• some transitions:

.button, button, input, textarea, select
    transition: border 0.3s, background-color 0.3s, color 0.3s

• responsive img:

img
    height: auto
    max-width: 100%

• media query to reset max-width on small screen devices:

// Smaller than mobile screen
@media (max-width: 40.0rem)
    .row
        flex-direction: column
        .column
            max-width: 100%

        .column
            &.column-10, &.column-20, &.column-33, &.column-34, &.column-40, &.column-50, &.column-60, &.column-66, &.column-67, &.column-75, &.column-80, &.column-90
                max-width: 100%

here is example:
http://codepen.io/vujovichigor/pen/NxvoOR
(try resizing browser)

Thank you for milligram :)

[cjpatoilo]

@vujovicigor Thanks for the suggestions, some have already been submitted, I will be providing other and they become available in the next update. =D