SASS warning due to bad contrast ratio

[willdurand]

Output of the CSS build:

WARNING: Contrast ratio of #f9f9f9 on #fefefe is pretty bad, just 1
Backtrace:
	node_modules/foundation-sites/scss/util/_color.scss:75, in function `color-pick-contrast`
	node_modules/foundation-sites/scss/components/_callout.scss:70, in mixin `callout-style`
	node_modules/foundation-sites/scss/components/_callout.scss:85, in mixin `callout`
	node_modules/foundation-sites/scss/components/_callout.scss:90, in mixin `foundation-callout`
	stdin:12

WARNING: Contrast ratio of #fefefe on #2fe2bf is pretty bad, just 1.6
Backtrace:
	node_modules/foundation-sites/scss/util/_color.scss:75, in function `color-pick-contrast`
	node_modules/foundation-sites/scss/components/_callout.scss:70, in mixin `callout-style`
	node_modules/foundation-sites/scss/components/_callout.scss:94, in mixin `foundation-callout`
	stdin:12

WARNING: Contrast ratio of #fefefe on #ededed is pretty bad, just 1.2
Backtrace:
	node_modules/foundation-sites/scss/util/_color.scss:75, in function `color-pick-contrast`
	node_modules/foundation-sites/scss/components/_callout.scss:70, in mixin `callout-style`
	node_modules/foundation-sites/scss/components/_callout.scss:94, in mixin `foundation-callout`
	stdin:12

WARNING: Contrast ratio of #f9f9f9 on #61e291 is pretty bad, just 1.6
Backtrace:
	node_modules/foundation-sites/scss/util/_color.scss:75, in function `color-pick-contrast`
	node_modules/foundation-sites/scss/components/_callout.scss:70, in mixin `callout-style`
	node_modules/foundation-sites/scss/components/_callout.scss:94, in mixin `foundation-callout`
	stdin:12

WARNING: Contrast ratio of #f9f9f9 on #ffbe33 is pretty bad, just 1.6
Backtrace:
	node_modules/foundation-sites/scss/util/_color.scss:75, in function `color-pick-contrast`
	node_modules/foundation-sites/scss/components/_callout.scss:70, in mixin `callout-style`
	node_modules/foundation-sites/scss/components/_callout.scss:94, in mixin `foundation-callout`
	stdin:12

WARNING: Contrast ratio of #fefefe on #f07966 is pretty bad, just 2.7
Backtrace:
	node_modules/foundation-sites/scss/util/_color.scss:75, in function `color-pick-contrast`
	node_modules/foundation-sites/scss/components/_callout.scss:70, in mixin `callout-style`
	node_modules/foundation-sites/scss/components/_callout.scss:94, in mixin `foundation-callout`
	stdin:12

WARNING: Contrast ratio of #f9f9f9 on #fefefe is pretty bad, just 1
Backtrace:
	node_modules/foundation-sites/scss/util/_color.scss:75, in function `color-pick-contrast`
	node_modules/foundation-sites/scss/components/_callout.scss:70, in mixin `callout-style`
	node_modules/foundation-sites/scss/components/_callout.scss:85, in mixin `callout`
	app/scss/components/_message_box.scss:9

WARNING: Contrast ratio of #f9f9f9 on #ffbe33 is pretty bad, just 1.6
Backtrace:
	node_modules/foundation-sites/scss/util/_color.scss:75, in function `color-pick-contrast`
	node_modules/foundation-sites/scss/components/_callout.scss:70, in mixin `callout-style`
	app/scss/components/_message_box.scss:25

WARNING: Contrast ratio of #fefefe on #f07966 is pretty bad, just 2.7
Backtrace:
	node_modules/foundation-sites/scss/util/_color.scss:75, in function `color-pick-contrast`
	node_modules/foundation-sites/scss/components/_callout.scss:70, in mixin `callout-style`
	app/scss/components/_message_box.scss:31

WARNING: Contrast ratio of #f9f9f9 on #61e291 is pretty bad, just 1.6
Backtrace:
	node_modules/foundation-sites/scss/util/_color.scss:75, in function `color-pick-contrast`
	node_modules/foundation-sites/scss/components/_callout.scss:70, in mixin `callout-style`
	app/scss/components/_message_box.scss:36

WARNING: Contrast ratio of #fefefe on #41e5c4 is pretty bad, just 1.6
Backtrace:
	node_modules/foundation-sites/scss/util/_color.scss:75, in function `color-pick-contrast`
	node_modules/foundation-sites/scss/components/_callout.scss:70, in mixin `callout-style`
	app/scss/components/_message_box.scss:41