diff options
Diffstat (limited to 'vendor/twbs/bootstrap/site/docs/4.5/content/reboot.md')
| -rw-r--r-- | vendor/twbs/bootstrap/site/docs/4.5/content/reboot.md | 380 |
1 files changed, 380 insertions, 0 deletions
diff --git a/vendor/twbs/bootstrap/site/docs/4.5/content/reboot.md b/vendor/twbs/bootstrap/site/docs/4.5/content/reboot.md new file mode 100644 index 000000000..2f0904f3f --- /dev/null +++ b/vendor/twbs/bootstrap/site/docs/4.5/content/reboot.md @@ -0,0 +1,380 @@ +--- +layout: docs +title: Reboot +description: Reboot, a collection of element-specific CSS changes in a single file, kickstart Bootstrap to provide an elegant, consistent, and simple baseline to build upon. +group: content +redirect_from: "/docs/4.5/content/" +toc: true +--- + +## Approach + +Reboot builds upon Normalize, providing many HTML elements with somewhat opinionated styles using only element selectors. Additional styling is done only with classes. For example, we reboot some `<table>` styles for a simpler baseline and later provide `.table`, `.table-bordered`, and more. + +Here are our guidelines and reasons for choosing what to override in Reboot: + +- Update some browser default values to use `rem`s instead of `em`s for scalable component spacing. +- Avoid `margin-top`. Vertical margins can collapse, yielding unexpected results. More importantly though, a single direction of `margin` is a simpler mental model. +- For easier scaling across device sizes, block elements should use `rem`s for `margin`s. +- Keep declarations of `font`-related properties to a minimum, using `inherit` whenever possible. + +## Page defaults + +The `<html>` and `<body>` elements are updated to provide better page-wide defaults. More specifically: + +- The `box-sizing` is globally set on every element—including `*::before` and `*::after`, to `border-box`. This ensures that the declared width of element is never exceeded due to padding or border. +- No base `font-size` is declared on the `<html>`, but `16px` is assumed (the browser default). `font-size: 1rem` is applied on the `<body>` for easy responsive type-scaling via media queries while respecting user preferences and ensuring a more accessible approach. +- The `<body>` also sets a global `font-family`, `line-height`, and `text-align`. This is inherited later by some form elements to prevent font inconsistencies. +- For safety, the `<body>` has a declared `background-color`, defaulting to `#fff`. + +## Native font stack + +The default web fonts (Helvetica Neue, Helvetica, and Arial) have been dropped in Bootstrap 4 and replaced with a "native font stack" for optimum text rendering on every device and OS. Read more about [native font stacks in this *Smashing Magazine* article](https://www.smashingmagazine.com/2015/11/using-system-ui-fonts-practical-guide/). + +{% highlight sass %} +$font-family-sans-serif: + // Safari for macOS and iOS (San Francisco) + -apple-system, + // Chrome < 56 for macOS (San Francisco) + BlinkMacSystemFont, + // Windows + "Segoe UI", + // Android + Roboto, + // Basic web fallback + "Helvetica Neue", Arial, + // Linux + "Noto Sans", + // Sans serif fallback + sans-serif, + // Emoji fonts + "Apple Color Emoji", "Segoe UI Emoji", "Segoe UI Symbol", "Noto Color Emoji" !default; +{% endhighlight %} + +This `font-family` is applied to the `<body>` and automatically inherited globally throughout Bootstrap. To switch the global `font-family`, update `$font-family-base` and recompile Bootstrap. + +## Headings and paragraphs + +All heading elements—e.g., `<h1>`—and `<p>` are reset to have their `margin-top` removed. Headings have `margin-bottom: .5rem` added and paragraphs `margin-bottom: 1rem` for easy spacing. + +<table> + <thead> + <tr> + <th>Heading</th> + <th>Example</th> + </tr> + </thead> + <tbody> + <tr> + <td> + {{ "`<h1></h1>`" | markdownify }} + </td> + <td><span class="h1">h1. Bootstrap heading</span></td> + </tr> + <tr> + <td> + {{ "`<h2></h2>`" | markdownify }} + </td> + <td><span class="h2">h2. Bootstrap heading</span></td> + </tr> + <tr> + <td> + {{ "`<h3></h3>`" | markdownify }} + </td> + <td><span class="h3">h3. Bootstrap heading</span></td> + </tr> + <tr> + <td> + {{ "`<h4></h4>`" | markdownify }} + </td> + <td><span class="h4">h4. Bootstrap heading</span></td> + </tr> + <tr> + <td> + {{ "`<h5></h5>`" | markdownify }} + </td> + <td><span class="h5">h5. Bootstrap heading</span></td> + </tr> + <tr> + <td> + {{ "`<h6></h6>`" | markdownify }} + </td> + <td><span class="h6">h6. Bootstrap heading</span></td> + </tr> + </tbody> +</table> + +## Lists + +All lists—`<ul>`, `<ol>`, and `<dl>`—have their `margin-top` removed and a `margin-bottom: 1rem`. Nested lists have no `margin-bottom`. + +<div class="bd-example"> +{% capture markdown %} +* Lorem ipsum dolor sit amet +* Consectetur adipiscing elit +* Integer molestie lorem at massa +* Facilisis in pretium nisl aliquet +* Nulla volutpat aliquam velit + * Phasellus iaculis neque + * Purus sodales ultricies + * Vestibulum laoreet porttitor sem + * Ac tristique libero volutpat at +* Faucibus porta lacus fringilla vel +* Aenean sit amet erat nunc +* Eget porttitor lorem + +1. Lorem ipsum dolor sit amet +2. Consectetur adipiscing elit +3. Integer molestie lorem at massa +4. Facilisis in pretium nisl aliquet +5. Nulla volutpat aliquam velit +6. Faucibus porta lacus fringilla vel +7. Aenean sit amet erat nunc +8. Eget porttitor lorem +{% endcapture %} +{{ markdown | markdownify }} +</div> + +For simpler styling, clear hierarchy, and better spacing, description lists have updated `margin`s. `<dd>`s reset `margin-left` to `0` and add `margin-bottom: .5rem`. `<dt>`s are **bolded**. + +<div class="bd-example"> + <dl> + <dt>Description lists</dt> + <dd>A description list is perfect for defining terms.</dd> + <dt>Euismod</dt> + <dd>Vestibulum id ligula porta felis euismod semper eget lacinia odio sem.</dd> + <dd>Donec id elit non mi porta gravida at eget metus.</dd> + <dt>Malesuada porta</dt> + <dd>Etiam porta sem malesuada magna mollis euismod.</dd> + </dl> +</div> + +## Preformatted text + +The `<pre>` element is reset to remove its `margin-top` and use `rem` units for its `margin-bottom`. + +<div class="bd-example"> +<pre> +.example-element { + margin-bottom: 1rem; +} +</pre> +</div> + +## Tables + +Tables are slightly adjusted to style `<caption>`s, collapse borders, and ensure consistent `text-align` throughout. Additional changes for borders, padding, and more come with [the `.table` class]({{ site.baseurl }}/docs/{{ site.docs_version }}/content/tables/). + +<div class="bd-example"> + <table> + <caption> + This is an example table, and this is its caption to describe the contents. + </caption> + <thead> + <tr> + <th>Table heading</th> + <th>Table heading</th> + <th>Table heading</th> + <th>Table heading</th> + </tr> + </thead> + <tbody> + <tr> + <td>Table cell</td> + <td>Table cell</td> + <td>Table cell</td> + <td>Table cell</td> + </tr> + <tr> + <td>Table cell</td> + <td>Table cell</td> + <td>Table cell</td> + <td>Table cell</td> + </tr> + <tr> + <td>Table cell</td> + <td>Table cell</td> + <td>Table cell</td> + <td>Table cell</td> + </tr> + </tbody> + </table> +</div> + +## Forms + +Various form elements have been rebooted for simpler base styles. Here are some of the most notable changes: + +- `<fieldset>`s have no borders, padding, or margin so they can be easily used as wrappers for individual inputs or groups of inputs. +- `<legend>`s, like fieldsets, have also been restyled to be displayed as a heading of sorts. +- `<label>`s are set to `display: inline-block` to allow `margin` to be applied. +- `<input>`s, `<select>`s, `<textarea>`s, and `<button>`s are mostly addressed by Normalize, but Reboot removes their `margin` and sets `line-height: inherit`, too. +- `<textarea>`s are modified to only be resizable vertically as horizontal resizing often "breaks" page layout. +- `<button>`s and `<input>` button elements have `cursor: pointer` when `:not(:disabled)`. + +These changes, and more, are demonstrated below. + +<form class="bd-example"> + <fieldset> + <legend>Example legend</legend> + + <p> + <label for="input">Example input</label> + <input type="text" id="input" placeholder="Example input"> + </p> + + <p> + <label for="select">Example select</label> + <select id="select"> + <option value="">Choose...</option> + <optgroup label="Option group 1"> + <option value="">Option 1</option> + <option value="">Option 2</option> + <option value="">Option 3</option> + </optgroup> + <optgroup label="Option group 2"> + <option value="">Option 4</option> + <option value="">Option 5</option> + <option value="">Option 6</option> + </optgroup> + </select> + </p> + + <p> + <label> + <input type="checkbox" value=""> + Check this checkbox + </label> + </p> + + <p> + <label> + <input type="radio" name="optionsRadios" id="optionsRadios1" value="option1" checked> + Option one is this and that + </label> + <label> + <input type="radio" name="optionsRadios" id="optionsRadios2" value="option2"> + Option two is something else that's also super long to demonstrate the wrapping of these fancy form controls. + </label> + <label> + <input type="radio" name="optionsRadios" id="optionsRadios3" value="option3" disabled> + Option three is disabled + </label> + </p> + + <p> + <label for="textarea">Example textarea</label> + <textarea id="textarea" rows="3"></textarea> + </p> + + <p> + <label for="date">Example date</label> + <input type="date" id="date"> + </p> + + <p> + <label for="time">Example time</label> + <input type="time" id="time"> + </p> + + <p> + <label for="output">Example output</label> + <output name="result" id="output">100</output> + </p> + + <p> + <button type="submit">Button submit</button> + <input type="submit" value="Input submit button"> + <input type="reset" value="Input reset button"> + <input type="button" value="Input button"> + </p> + + <p> + <button type="submit" disabled>Button submit</button> + <input type="submit" value="Input submit button" disabled> + <input type="reset" value="Input reset button" disabled> + <input type="button" value="Input button" disabled> + </p> + </fieldset> +</form> + +### Pointers on buttons + +Reboot includes an enhancement for `role="button"` to change the default cursor to `pointer`. Add this attribute to elements to help indicate elements are interactive. This role isn't necessary for `<button>` elements, which get their own `cursor` change. + +{% capture example %} +<span role="button">Non-button element button</span> +{% endcapture %} +{% include example.html content=example %} + +## Misc elements + +### Address + +The `<address>` element is updated to reset the browser default `font-style` from `italic` to `normal`. `line-height` is also now inherited, and `margin-bottom: 1rem` has been added. `<address>`s are for presenting contact information for the nearest ancestor (or an entire body of work). Preserve formatting by ending lines with `<br>`. + +<div class="bd-example"> + <address> + <strong>Twitter, Inc.</strong><br> + 1355 Market St, Suite 900<br> + San Francisco, CA 94103<br> + <abbr title="Phone">P:</abbr> (123) 456-7890 + </address> + + <address> + <strong>Full Name</strong><br> + <a href="mailto:first.last@example.com">first.last@example.com</a> + </address> +</div> + +### Blockquote + +The default `margin` on blockquotes is `1em 40px`, so we reset that to `0 0 1rem` for something more consistent with other elements. + +<div class="bd-example"> + <blockquote class="blockquote"> + <p>Lorem ipsum dolor sit amet, consectetur adipiscing elit. Integer posuere erat a ante.</p> + <footer>Someone famous in <cite title="Source Title">Source Title</cite></footer> + </blockquote> +</div> + +### Inline elements + +The `<abbr>` element receives basic styling to make it stand out amongst paragraph text. + +<div class="bd-example"> + Nulla <abbr title="attribute">attr</abbr> vitae elit libero, a pharetra augue. +</div> + +### Summary + +The default `cursor` on summary is `text`, so we reset that to `pointer` to convey that the element can be interacted with by clicking on it. + +<div class="bd-example"> + <details> + <summary>Some details</summary> + <p>More info about the details.</p> + </details> + + <details open> + <summary>Even more details</summary> + <p>Here are even more details about the details.</p> + </details> +</div> + +## HTML5 `[hidden]` attribute + +HTML5 adds [a new global attribute named `[hidden]`](https://developer.mozilla.org/en-US/docs/Web/HTML/Global_attributes/hidden), which is styled as `display: none` by default. Borrowing an idea from [PureCSS](https://purecss.io/), we improve upon this default by making `[hidden] { display: none !important; }` to help prevent its `display` from getting accidentally overridden. While `[hidden]` isn't natively supported by IE10, the explicit declaration in our CSS gets around that problem. + +{% highlight html %} +<input type="text" hidden> +{% endhighlight %} + +{% capture callout %} +##### jQuery incompatibility + +`[hidden]` is not compatible with jQuery's `$(...).hide()` and `$(...).show()` methods. Therefore, we don't currently especially endorse `[hidden]` over other techniques for managing the `display` of elements. +{% endcapture %} +{% include callout.html content=callout type="warning" %} + +To merely toggle the visibility of an element, meaning its `display` is not modified and the element can still affect the flow of the document, use [the `.invisible` class]({{ site.baseurl }}/docs/{{ site.docs_version }}/utilities/visibility/) instead. |