Changing the default behaviour of `.is-fluid` container: removing media breakpoint from the rule, so the behaviour is consistent with described in docs:
```
This container is fluid: it will have a 32px gap on either side, on any viewport size.
```
* fieldset disabled styles
* Added disabled styles to button elements included inside a disabled fieldset
* Added comma, and fieldset element reset
* fieldset doesn't need display block
* #2091 remove css rule which causes has-addons to not work correctly
* #2091 remove css rule which causes has-addons to not work correctly
* #2091 Don't include compiled css
* #2091 Don't include compiled css
* Extract input placeholder colors to variables
This makes it easier to override the color colour of the placeholder text in an input.
* Remove semicolon, because SASS.
This is SASS, not SCSS.
If there is only one child inside a field with addons, the current first and last child selectors remove any radius. Since a single control would be both a first and last child at the same time, it gets canceled out. This leverages the :only-child property to not apply this rule if there is only one control.
* <!-- PLEASE READ THE FOLLOWING INSTRUCTIONS -->
<!-- DO NOT REBUILD THE CSS OUTPUT IN YOUR PR -->
<!-- Choose one of the following: -->
This is a bugfix
<!-- New feature? Update the CHANGELOG.md too, and eventually the Docs. -->
<!-- Improvement? Explain how and why. -->
<!-- Bugfix? Reference that issue as well. -->
If a form field is disabled and that form field uses has add-on element ( has-addons ), hover state is overlapping to add-on element.
### Proposed solution
<!-- Which specific problem does this PR solve and how? -->
<!-- If it fixes a particular Issue, add "Fixes #ISSUE_NUMBER" in your title -->
This solution excludes disabled form elements hover state which is used within has-addons fields wrapper.
Fixes#1992
### Tradeoffs
<!-- What are the drawbacks of this solution? Are there alternative ones? -->
<!-- Think of performance, build time, usability, complexity, coupling…) -->
No tradeoffs.
### Testing Done
I checkout out master and changed the lines.
* Disabled form elements hover state is overlapping, if control has add-ons elements
If a form field is disabled and that form field uses has add-on element ( has-addons ), hover state is overlapping to add-on element.
* Disabled form elements hover state is overlapping, if control has add-ons elements
If a form field is disabled and that form field uses has add-on element ( has-addons ), hover state is overlapping to add-on element.
Corrects the problem of the .has-icon-left / .has-icon-right fields floating out of the input area when a .help element is floated to the right of a preceding input
