CSS module: box sizing & box model

files/en-us/glossary/intrinsic_size/index.md

@@ -6,12 +6,64 @@ page-type: glossary-definition
 
 {{GlossarySidebar}}
 
-In CSS, the _intrinsic size_ of an element is the size it would be based on its content, if no external factors were applied to it. For example, inline elements are sized intrinsically: `width`, `height`, and vertical margin and padding have no impact, though horizontal margin and padding do.
+In CSS, the _intrinsic size_ of an element is the size it would be based purely on its content without taking into account the effects of the context it appears in. For example, the sizing applied by CSS [box model](/en-US/docs/Learn/CSS/Building_blocks/The_box_model) properties. An element's intrinsic sizes are represented by its {{cssxref("min-content")}} and {{cssxref("max-content")}} sizes.
 
-How intrinsic sizes are calculated is defined in the [CSS Intrinsic and Extrinsic Sizing Specification](https://www.w3.org/TR/css-sizing-3/#intrinsic-sizes).
+Inline elements are sized intrinsically: [sizing](/en-US/docs/Web/CSS/CSS_box_sizing) and [box](/en-US/docs/Web/CSS/CSS_box_model) properties including {{cssxref("height")}}, {{cssxref("width")}}, {{cssxref("block-size")}}, {{cssxref("inline-size")}}, and {{cssxref("padding-block")}} and {{cssxref("margin-block")}} have no impact on them ( though {{cssxref("margin-inline")}} and {{cssxref("padding-inline")}} do).
 
-Intrinsic sizing takes into account the `min-content` and `max-content` size of an element. For text the `min-content` size would be if the text wrapped as small as it can in the inline direction without causing an overflow, doing as much soft-wrapping as possible. For a box containing a string of text, the `min-content` size would be defined by the longest word. The keyword value of `min-content` for the {{cssxref("width")}} property will size an element according to the `min-content` size.
+For example, the minimum intrinsic size of the inline {{htmlelement("span")}} element is the minimum size it would have if it was floated (with no other CSS box properties applied), inside a container with an inline-size of `0px`. The maximum intrinsic size is the opposite. It is the size the same `<span>` would have if its container's inline size were infinite.
 
-The `max-content` size is the opposite — in the case of text, this would have the text display as wide as possible, doing no soft-wrapping, even if an overflow was caused. The keyword value `max-content` exposes this behavior.
+Intrinsic size has the same meaning for images as for text — the size at which the images are displayed if no CSS is applied to change the rendering.
 
-For images the intrinsic size has the same meaning — it is the size that an image would be displayed if no CSS was applied to change the rendering. By default images are assumed to have a "1x" pixel density (1 device pixel = 1 CSS pixel) and so the intrinsic size is simply the pixel height and width. The intrinsic image size and resolution can be explicitly specified in the {{Glossary("EXIF")}} data. The intrinsic pixel density may also be set for images using the [`srcset`](/en-US/docs/Web/HTML/Element/img#srcset) attribute (note that if both mechanisms are used, the `srcset` value is applied "over" the EXIF value).
+Pixel density and resolution affect intrinsic size. By default, images are assumed to have a "1x" pixel density (1 device pixel = 1 CSS pixel), in which case the intrinsic size is simply the pixel height and width. An image's intrinsic size and resolution can be explicitly specified in its {{Glossary("EXIF")}} data. Image pixel density may also be set for images using the [`srcset`](/en-US/docs/Web/HTML/Element/img#srcset) attribute. Note that, if both mechanisms are used, the `srcset` value is applied "over" the EXIF value.
+
+Intrinsic sizes and how they are calculated are defined in the [CSS sizing module](/en-US/docs/Web/CSS/CSS_box_sizing).
+
+#### minimum intrinsic size
+
+To set an element according to its minimum intrinsic size, set the {{cssxref("inline-size")}} (or {{cssxref("width")}} in horizontal writing modes, like English and Hebrew) to {{cssxref("min-content")}}. This sets the element to the size it would be if the text was wrapped as small as possible in the inline direction without causing an overflow, with as much soft-wrapping as possible. For a box containing a string of text, the minimum intrinsic size would be defined by the longest word.
+
+```html hidden
+<p>Text wraps, making the element only as wide as its longest word.</p>
+```
+
+```css
+p {
+  inline-size: min-content;
+  background-color: palegoldenrod;
+}
+```
+
+{{ EmbedLiveSample('minimum intrinsic size', '100%', '220') }}
+
+#### maximum intrinsic size
+
+The maximum intrinsic size is the opposite. It is the element's size if the container's inline size were infinite. Text content would display as wide as possible, with no soft-wrapping, even if it overflowed its container. The keyword value {{cssxref("max-content")}} sets this behavior.
+
+```html hidden
+<p>Element grows as text doesn't wrap.</p>
+<p>
+  This paragraph may be wider than the width of the entire page and yet it won't
+  wrap because <code>width: max-content</code> is set. It therefore may overflow
+  its container.
+</p>
+```
+
+```css
+p {
+  width: max-content;
+  background-color: palegoldenrod;
+}
+```
+
+{{ EmbedLiveSample('maximum intrinsic size', '100%', '200') }}
+
+## Extrinsic sizing
+
+The opposite of _intrinsic size_ is **_extrinsic size_**, which is based on the context of an element, without regard for its contents. Extrinsic sizing is determined by box model property values. With extrinsic sizing, percentages specify the size of a box with respect to the box's containing block.
+
+## See also
+
+- CSS {{cssxref("min-content")}}, {{cssxref("max-content")}}, and {{cssxref("fit-content")}} property values.
+- CSS {{cssxref("aspect-ratio")}} property
+- [CSS box sizing](/en-US/docs/Web/CSS/CSS_box_sizing) module
+- [CSS sizing specification: intrinsic sizes](https://www.w3.org/TR/css-sizing-3/#intrinsic-sizes)

files/en-us/web/css/css_box_model/index.md

@@ -2,77 +2,137 @@
 title: CSS box model
 slug: Web/CSS/CSS_box_model
 page-type: css-module
-spec-urls: https://drafts.csswg.org/css-box/
+spec-urls:
+  - https://drafts.csswg.org/css-box-4/
+  - https://drafts.csswg.org/css-box-3/
 ---
 
 {{CSSRef}}
 
-The **CSS box model** module defines the rectangular boxes, including their padding and margin, that are generated for elements and laid out according to the [visual formatting model](/en-US/docs/Web/CSS/Visual_formatting_model).
+The **CSS box model** module defines the `height`, `width`, `margin`, and `padding` properties, which along with [border properties](/en-US/docs/Web/CSS/CSS_backgrounds_and_borders) make up the CSS [box model](/en-US/docs/Web/CSS/CSS_box_model/Introduction_to_the_CSS_box_model).
 
-## Box model overview
+Every visible element on a webpage is a box laid out according to the [visual formatting model](/en-US/docs/Web/CSS/Visual_formatting_model). CSS properties define their size, position, and stacking level, with the box model properties (and others) defining the extrinsic size of each box, and the space around them.
 
-A box in CSS consists of a content area, which is where any text, images, or other HTML elements are displayed. This is optionally surrounded by padding, a border, and a margin, on one or more sides. The box model describes how these elements work together to create a box as displayed by CSS. To learn more about it read [Introduction to the CSS box model](/en-US/docs/Web/CSS/CSS_box_model/Introduction_to_the_CSS_box_model).
+Each box has a rectangular content area, inside which any text, images, and other content is displayed. The content may be surrounded by padding, a border, and a margin, on one or more sides. The padding is around the content, the border is around the padding, and the margin sits outside the border. The box model describes how these features — the content, padding, border, and margin — work together to create a box as displayed by CSS.
 
-### Box-edge keywords
+![The components of the CSS box model](boxmodel.png)
 
-The Box Model specification defines a set of keywords that refer to the edges of each part of the box, these are used as keyword values in CSS including as a value for the {{cssxref("box-sizing")}} property, to control how the box model calculates its size.
-
-- `content-box`
-  - : The edge of the content area of the box.
-- `padding-box`
-  - : The edge of the padding of the box, if there is no padding on a side then this is the same as `content-box`.
-- `border-box`
-  - : The edge of the border of the box, if there is no border on a side then this is the same as `padding-box`.
-- `margin-box`
-  - : The edge of the margin of the box, if there is no margin on a side then this is the same as `border-box`.
-- `stroke-box`
-  - : In SVG refers to the stroke bounding box, in CSS treated as `content-box`.
-- `view-box`
-  - : In SVG refers to the nearest SVG viewport element's origin box, which is a rectangle with the width and height of the initial SVG user coordinate system established by the {{svgattr("viewBox")}} attribute for that element. In CSS treated as `border-box`.
+The CSS box model module defines physical (or "page relative") properties such as `width` and `margin-top`. Flow-relative properties such as `inline-size` and `margin-block-start` (which relate to text direction) are defined in [Logical Properties and Values](/en-US/docs/Web/CSS/CSS_logical_properties_and_values). The box model module is extended by the [CSS box sizing module](/en-US/docs/Web/CSS/CSS_box_sizing), which introduces the {{glossary("intrinsic size")}} value and enables defining aspect ratios for elements that are auto-sized in at least one dimension.
 
 ## Reference
 
-> **Note:** This specification defines the physical padding and margin properties. Flow-relative properties, which relate to text direction, are defined in [Logical Properties and Values](/en-US/docs/Web/CSS/CSS_logical_properties_and_values).
-
-### Properties for controlling the margin of a box
-
-Margins surround the border edge of a box, and provide spacing between boxes.
-
-- {{CSSxRef("margin")}}
-- {{CSSxRef("margin-bottom")}}
-- {{CSSxRef("margin-left")}}
-- {{CSSxRef("margin-right")}}
-- {{CSSxRef("margin-top")}}
-- {{CSSxRef("margin-trim")}}
-
-### Properties for controlling the padding for a box
-
-Padding is inserted between the content edge and border edge of a box.
-
-- {{CSSxRef("padding")}}
-- {{CSSxRef("padding-bottom")}}
-- {{CSSxRef("padding-left")}}
-- {{CSSxRef("padding-right")}}
-- {{CSSxRef("padding-top")}}
-
-### Other properties
-
-There are other properties that relate to the box model, that are defined elsewhere.
-
-- [Borders](/en-US/docs/Web/CSS/CSS_backgrounds_and_borders)
-  - : The border properties specify the thickness of the border, drawing style and color.
-- [Overflow](/en-US/docs/Web/CSS/overflow)
-  - : Controls what happens when there is too much content to fit into a box.
+### Properties
+
+- {{cssxref("box-sizing")}}
+- {{cssxref("height")}}
+- {{cssxref("margin")}}
+- {{cssxref("margin-bottom")}}
+- {{cssxref("margin-left")}}
+- {{cssxref("margin-right")}}
+- {{cssxref("margin-top")}}
+- {{cssxref("margin-trim")}}
+- {{cssxref("max-height")}}
+- {{cssxref("max-width")}}
+- {{cssxref("min-height")}}
+- {{cssxref("min-width")}}
+- {{cssxref("padding")}}
+- {{cssxref("padding-bottom")}}
+- {{cssxref("padding-left")}}
+- {{cssxref("padding-right")}}
+- {{cssxref("padding-top")}}
+- {{cssxref("width")}}
+
+### Data types
+
+- [`<box>`](/en-US/docs/Web/CSS/box-edge)
+  - [`<visual-box>`](/en-US/docs/Web/CSS/box-edge#visual_box)
+  - [`<layout-box>`](/en-US/docs/Web/CSS/box-edge#layout_box)
+  - [`<paint-box>`](/en-US/docs/Web/CSS/box-edge#paing_box)
+  - [`<coord-box>`](<(/en-US/docs/Web/CSS/box-edge#coord_box)>)
 
 ## Guides
 
 - [Introduction to the CSS box model](/en-US/docs/Web/CSS/CSS_box_model/Introduction_to_the_CSS_box_model)
-  - : Explains one of the fundamental concept of CSS: the box model. This model defines how CSS lays out elements, including their content, padding, border, and margin areas.
+
+  - : Explains one of the fundamental concepts of CSS: the box model. This model defines how CSS lays out elements, including their content, padding, border, and margin areas.
+
 - [Mastering margin collapsing](/en-US/docs/Web/CSS/CSS_box_model/Mastering_margin_collapsing)
+
   - : Sometimes, two adjacent margins are collapsed into one. This article describes the rules that govern when and why this happens, and how to control it.
+
 - [Visual formatting model](/en-US/docs/Web/CSS/Visual_formatting_model)
+
   - : Explains the visual formatting model.
 
+## Related concepts
+
+- [CSS backgrounds and borders](/en-US/docs/Web/CSS/CSS_backgrounds_and_borders) module
+  - {{cssxref("border-width")}} shorthand
+  - {{cssxref("border-bottom-width")}}
+  - {{cssxref("border-left-width")}}
+  - {{cssxref("border-right-width")}}
+  - {{cssxref("border-top-width")}}
+- [CSS logical properties](/en-US/docs/Web/CSS/CSS_logical_properties_and_values) module
+  - {{CSSxRef("block-size")}}
+  - {{CSSxRef("inline-size")}}
+  - {{CSSxRef("max-block-size")}}
+  - {{CSSxRef("max-inline-size")}}
+  - {{CSSxRef("min-block-size")}}
+  - {{CSSxRef("min-inline-size")}}
+  - {{CSSxRef("margin-block")}}
+  - {{CSSxRef("margin-block-end")}}
+  - {{CSSxRef("margin-block-start")}}
+  - {{CSSxRef("margin-inline")}}
+  - {{CSSxRef("margin-inline-end")}}
+  - {{CSSxRef("margin-inline-start")}}
+  - {{CSSxRef("padding-block")}}
+  - {{CSSxRef("padding-block-end")}}
+  - {{CSSxRef("padding-block-start")}}
+  - {{CSSxRef("padding-inline")}}
+  - {{CSSxRef("padding-inline-end")}}
+  - {{CSSxRef("padding-inline-start")}}
+  - {{CSSxRef("border-block")}}
+  - {{CSSxRef("border-block-end")}}
+  - {{CSSxRef("border-block-end-width")}}
+  - {{CSSxRef("border-block-start")}}
+  - {{CSSxRef("border-block-start-width")}}
+  - {{CSSxRef("border-block-style")}}
+  - {{CSSxRef("border-block-width")}}
+  - {{CSSxRef("border-inline")}}
+  - {{CSSxRef("border-inline-end")}}
+  - {{CSSxRef("border-inline-end-width")}}
+  - {{CSSxRef("border-inline-start")}}
+  - {{CSSxRef("border-inline-start-width")}}
+  - {{CSSxRef("border-inline-width")}}
+- [CSS box sizing](/en-US/docs/Web/CSS/CSS_box_sizing) module
+  - {{cssxref("aspect-ratio")}}
+  - {{cssxref("contain-intrinsic-block-size")}}
+  - {{cssxref("contain-intrinsic-height")}}
+  - {{cssxref("contain-intrinsic-inline-size")}}
+  - {{cssxref("contain-intrinsic-size")}}
+  - {{cssxref("contain-intrinsic-width")}}
+  - {{cssxref("max-height")}}
+  - {{cssxref("max-width")}}
+  - {{cssxref("min-height")}}
+  - {{cssxref("min-width")}}
+- [CSS overflow](/en-US/docs/Web/CSS/CSS_overflow) module
+  - {{CSSxRef("overflow")}} shorthand
+  - {{CSSxRef("overflow-block")}}
+  - {{CSSxRef("overflow-clip-margin")}}
+  - {{CSSxRef("overflow-inline")}}
+  - {{CSSxRef("overflow-x")}}
+  - {{CSSxRef("overflow-y")}}
+  - {{CSSxRef("text-overflow")}}
+
 ## Specifications
 
 {{Specifications}}
+
+## See also
+
+- [CSS display](/en-US/docs/Web/CSS/CSS_display) module
+- [CSS flex layout](/en-US/docs/Web/CSS/CSS_flexible_box_layout) module
+- [CSS grid layout](/en-US/docs/Web/CSS/CSS_grid_layout) module
+- [CSS table](/en-US/docs/Web/CSS/CSS_table) module
+- [CSS positioned layout](/en-US/docs/Web/CSS/CSS_positioned_layout) module
+- [CSS fragmentation](/en-US/docs/Web/CSS/CSS_fragmentation) module