Howl.css — A loyal companion for your HTML

Howl is a loyal, classless CSS framework that follows your HTML wherever it goes. Named after my Shih Tzu, it's designed to bark at the complexity of modern web dev—giving you a beautiful, semantic site using nothing but the tags you already know.

Howl styles the content, not the layout. Howl provides 100% semantic coverage for every MDN tag. Howl does not touch broad containers like <div>, <section>, or <main> — layout is your business, the details are mine.

Howl is perfect for prototyping and honing your semantic HTML skills. However, please avoid using it in production, as classless CSS has inherent scaling limitations. It’s a great way to rediscover the power of native HTML elements.


Content sectioning

Content sectioning elements allow you to organize the document content into logical pieces. Use the sectioning elements to create a broad outline for your page content, including header and footer navigation, and heading elements to identify sections of content.

<article> (Unstyled)

Represents a self-contained composition in a document, page, application, or site, which is intended to be independently distributable or reusable (e.g., in syndication). Examples include a forum post, a magazine or newspaper article, a blog entry, a product card, a user-submitted comment, an interactive widget or gadget, or any other independent item of content.

<aside> (Unstyled)

Represents a portion of a document whose content is only indirectly related to the document's main content. Asides are frequently presented as sidebars or call-out boxes.

<footer> (Unstyled)

Represents a footer for its nearest ancestor sectioning content or sectioning root element. A <footer> typically contains information about the author of the section, copyright data, or links to related documents.

<header> (Unstyled)

Represents introductory content, typically a group of introductory or navigational aids. It may contain some heading elements but also a logo, a search form, an author name, and other elements.

<h1>, <h2>, <h3>, <h4>, <h5>, <h6>

Represent six levels of section headings. <h1> is the highest section level and <h6> is the lowest.

The Alpha Wolf (H1)

This is the primary heading for the page or a major section.

The Pack Leader (H2)

Used for major sub-sections of your content.

The Beta Member (H3)

Perfect for sub-topics within an H2 section.

The Scout (H4)

Grouping related items or smaller sub-points.

The Prowler (H5)

Often used for sidebar headers or small utility headings.

The Omega (H6)

The smallest level of heading, used for very specific fine-print sections.

<hgroup>

Represents a heading grouped with any secondary content, such as subheadings, an alternative title, or a tagline.

The Howl Project

A minimalist design system for the modern web

This is a standard paragraph. In a classless system, the goal is to let the natural flow of the document dictate the spacing. Because the max-width is limited, the line length remains comfortable for the eyes.

<main> (Unstyled)

Represents the dominant content of the body of a document. The main content area consists of content that is directly related to or expands upon the central topic of a document, or the central functionality of an application.

<nav> (Unstyled)

Represents a section of a page whose purpose is to provide navigation links, either within the current document or to other documents. Common examples of navigation sections are menus, tables of contents, and indexes.

<section> (Unstyled)

Represents a generic standalone section of a document, which doesn't have a more specific semantic element to represent it. Sections should always have a heading, with very few exceptions.

<search> (Unstyled)

Represents a part that contains a set of form controls or other content related to performing a search or filtering operation.


Text content

Use HTML text content elements to organize blocks or sections of content placed between the opening <body> and closing </body> tags. Important for accessibility and SEO, these elements identify the purpose or structure of that content.

<blockquote>

Indicates that the enclosed text is an extended quotation. Usually, this is rendered visually by indentation. A URL for the source of the quotation may be given using the cite attribute, while a text representation of the source can be given using the <cite> element.

For 50 years, WWF has been protecting the future of nature. The world's leading conservation organization, WWF works in 100 countries and is supported by 1.2 million members in the United States and close to 5 million globally.

<dd>

Provides the description, definition, or value for the preceding term (<dt>) in a description list (<dl>).

Architect
Howl Design Collective
Location
The High Sierras
Year Completed
2026

<div> (Unstyled)

The generic container for flow content. It has no effect on the content or layout until styled in some way using CSS (e.g., styling is directly applied to it, or some kind of layout model like flexbox is applied to its parent element).

<dl>

Represents a description list. The element encloses a list of groups of terms (specified using the <dt> element) and descriptions (provided by <dd> elements). Common uses for this element are to implement a glossary or to display metadata (a list of key-value pairs).

Architect
Howl Design Collective
Location
The High Sierras
Year Completed
2026

<dt>

Specifies a term in a description or definition list, and as such must be used inside a <dl> element. It is usually followed by a <dd> element; however, multiple <dt> elements in a row indicate several terms that are all defined by the immediate next <dd> element.

Architect
Howl Design Collective
Location
The High Sierras
Year Completed
2026

<figcaption>

Represents a caption or legend describing the rest of the contents of its parent <figure> element.

A snowy mountain peak during sunset.
The view from the base camp at dusk, 2026.

<figure>

Represents self-contained content, potentially with an optional caption, which is specified using the <figcaption> element. The figure, its caption, and its contents are referenced as a single unit.

A snowy mountain peak during sunset.
A placeholder image, 2026.

<hr>

Represents a thematic break between paragraph-level elements: for example, a change of scene in a story, or a shift of topic within a section.

This is the end of the first section.


The horizontal rule above provides a clean break.

<li>

Represents an item in a list. It must be contained in a parent element: an ordered list (<ol>), an unordered list (<ul>), or a menu (<menu>). In menus and unordered lists, list items are usually displayed using bullet points. In ordered lists, they are usually displayed with an ascending counter on the left, such as a number or letter.

  • Neil Armstrong
  • Alan Bean
  • Peter Conrad
  • Edgar Mitchell
  • Alan Shepard
  1. Neil Armstrong
  2. Alan Bean
  3. Peter Conrad
  4. Edgar Mitchell
  5. Alan Shepard

<menu>

A semantic alternative to <ul>, but treated by browsers (and exposed through the accessibility tree) as no different than <ul>. It represents an unordered list of items (which are represented by <li> elements).

  • Neil Armstrong
  • Alan Bean
  • Peter Conrad
  • Edgar Mitchell
  • Alan Shepard
  • <ol>

    Represents an ordered list of items — typically rendered as a numbered list.

    1. Neil Armstrong
    2. Alan Bean
    3. Peter Conrad
    4. Edgar Mitchell
    5. Alan Shepard

    <p>

    Represents a paragraph. Paragraphs are usually represented in visual media as blocks of text separated from adjacent blocks by blank lines and/or first-line indentation, but HTML paragraphs can be any structural grouping of related content, such as images or form fields.

    Lorem ipsum dolor, sit amet consectetur adipisicing elit. Esse vel eos facilis iusto voluptatem, expedita sint quae beatae temporibus aliquid delectus ipsam dolor repellendus repudiandae eius commodi quo corporis accusamus?

    <pre>

    Represents preformatted text which is to be presented exactly as written in the HTML file. The text is typically rendered using a non-proportional, or monospaced font. Whitespace inside this element is displayed as written.

    body {
    	font-family: "Nunito";
    	background-color: var(--howl-warm-white);
    	tab-size: 4;
    }

    <ul>

    Represents an unordered list of items, typically rendered as a bulleted list.

    • Neil Armstrong
    • Alan Bean
    • Peter Conrad
    • Edgar Mitchell
    • Alan Shepard

    Inline text semantics

    Use the HTML inline text semantic to define the meaning, structure, or style of a word, line, or any arbitrary piece of text.

    <a>

    Together with its href attribute, creates a hyperlink to web pages, files, email addresses, locations within the current page, or anything else a URL can address.

    Our latest project focuses on Sustainable Urbanism and the integration of Natural Light in brutalist structures.

    <abbr>

    Represents an abbreviation or acronym.

    You can use CSS (Cascading Style Sheets) to style your HTML (HyperText Markup Language). Using style sheets, you can keep your CSS presentation layer and HTML content layer separate. This is called "separation of concerns."

    <b>

    Used to draw the reader's attention to the element's contents, which are not otherwise granted special importance. This was formerly known as the Boldface element, and most browsers still draw the text in boldface. However, you should not use <b> for styling text or granting importance. If you wish to create boldface text, you should use the CSS font-weight property. If you wish to indicate an element is of special importance, you should use the <strong> element.

    The two most popular science courses offered by the school are chemistry (the study of chemicals and the composition of substances) and physics (the study of the nature and properties of matter and energy).

    <bdi>

    Tells the browser's bidirectional algorithm to treat the text it contains in isolation from its surrounding text. It's particularly useful when a website dynamically inserts some text and doesn't know the directionality of the text being inserted.

    • Evil Steven: 1st place
    • François fatale: 2nd place
    • 이지훈: 4th place

    <bdo>

    Overrides the current directionality of text, so that the text within is rendered in a different direction.

    The English song "Oh I do like to be beside the seaside"

    Looks like this in Hebrew: אה, אני אוהב להיות ליד חוף הים

    In the computer's memory, this is stored as אה, אני אוהב להיות ליד חוף הים

    <br>

    Produces a line break in text (carriage-return). It is useful for writing a poem or an address, where the division of lines is significant.

    Lorem ipsum dolor sit amet consectetur adipisicing elit. <br>
    Eveniet maiores excepturi, nihil nemo enim labore eum eos incidunt saepe similique, molestiae autem sequi quae non aliquam nam error neque laudantium!

    <cite>

    Used to mark up the title of a creative work. The reference may be in an abbreviated form according to context-appropriate conventions related to citation metadata.

    The design principles for this studio were heavily influenced by The Poetics of Space by Gaston Bachelard.

    Form follows function—that has been misunderstood. Form and function should be one, joined in a spiritual union.
    — Frank Lloyd Wright, An Organic Architecture

    <code>

    Displays its contents styled in a fashion intended to indicate that the text is a short fragment of computer code. By default, the content text is displayed using the user agent's default monospace font.

    To change the site accent, simply update the --howl-golden-brown variable in your root stylesheet.

    body {
    	font-family: "Nunito";
    	background-color: var(--howl-warm-white);
    	tab-size: 4;
    }

    <data>

    Links a given piece of content with a machine-readable translation. If the content is time- or date-related, the <time> element must be used.

    New Products:

    • Mini Ketchup
    • Jumbo Ketchup
    • Mega Jumbo Ketchup

    <dfn>

    Used to indicate the term being defined within the context of a definition phrase or sentence. The ancestor <p> element, the <dt>/<dd> pairing, or the nearest section ancestor of the <dfn> element, is considered to be the definition of the term.

    In structural engineering, Tensegrity is a design principle based on a system of isolated components under compression inside a network of continuous tension.

    <em>

    Marks text that has stress emphasis. The <em> element can be nested, with each nesting level indicating a greater degree of emphasis.

    It is essential that the foundation is laid before the structural steel arrives on site.

    <i>

    Represents a range of text that is set off from the normal text for some reason, such as idiomatic text, technical terms, and taxonomical designations, among others. Historically, these have been presented using italicized type, which is the original source of the <i> naming of this element.

    The term trompe-l'œil is often used to describe architectural details that create an optical illusion of three-dimensionality.

    <kbd>

    Represents a span of inline text denoting textual user input from a keyboard, voice input, or any other text entry device. By convention, the user agent defaults to rendering the contents of a <kbd> element using its default monospace font, although this is not mandated by the HTML standard.

    To view the wireframe overlay, press Ctrl + Shift + W.

    Please press Ctrl + Shift + R to re-render an MDN page.

    <mark>

    Represents text which is marked or highlighted for reference or notation purposes due to the marked passage's relevance in the enclosing context.

    The primary goal of the renovation was to maximize natural light without compromising the structural integrity of the original 1920s frame.

    <q>

    Indicates that the enclosed text is a short inline quotation. Most modern browsers implement this by surrounding the text in quotation marks. This element is intended for short quotations that don't require paragraph breaks; for long quotations use the <blockquote> element.

    When Dave asks HAL to open the pod bay door, HAL answers: I'm sorry, Dave. I'm afraid I can't do that.

    <rp>

    Used to provide fall-back parentheses for browsers that do not support the display of ruby annotations using the <ruby> element. One <rp> element should enclose each of the opening and closing parentheses that wrap the <rt> element that contains the annotation's text.

    (kan)(ji)

    <rt>

    Specifies the ruby text component of a ruby annotation, which is used to provide pronunciation, translation, or transliteration information for East Asian typography. The <rt> element must always be contained within a <ruby> element.

    (kan)(ji)

    <ruby>

    Represents small annotations that are rendered above, below, or next to base text, usually used for showing the pronunciation of East Asian characters. It can also be used for annotating other kinds of text, but this usage is less common.

    (kan)(ji)

    <s>

    Renders text with a strikethrough, or a line through it. Use the <s> element to represent things that are no longer relevant or no longer accurate. However, <s> is not appropriate when indicating document edits; for that, use the <del> and <ins> elements, as appropriate.

    The initial material for the cladding was Brushed Aluminum but has been updated to Copper for better weathering.

    <samp>

    Used to enclose inline text which represents sample (or quoted) output from a computer program. Its contents are typically rendered using the browser's default monospaced font (such as Courier or Lucida Console).

    After running the structural analysis, the console returned Error: Load-bearing limit exceeded on Axis B.

    Initializing structural analysis...
    Checking load-bearing Axis B: [OK]
    Checking load-bearing Axis C: [FAIL]
    Error: Stress limit exceeded.

    <small>

    Represents side-comments and small print, like copyright and legal text, independent of its styled presentation. By default, it renders text within it one font size smaller, such as from small to x-small.

    MDN Web Docs is a learning platform for Web technologies and the software that powers the Web.

    The content is licensed under a Creative Commons Attribution-ShareAlike 2.5 Generic License.

    <span> (Unstyled)

    A generic inline container for phrasing content, which does not inherently represent anything. It can be used to group elements for styling purposes (using the class or id attributes), or because they share attribute values, such as lang. It should be used only when no other semantic element is appropriate. <span> is very much like a <div> element, but <div> is a block-level element whereas a <span> is an inline-level element.

    <strong>

    Indicates that its contents have strong importance, seriousness, or urgency. Browsers typically render the contents in bold type.

    Before proceeding, make sure you put on your safety goggles.

    <sub>

    Specifies inline text which should be displayed as subscript for solely typographical reasons. Subscripts are typically rendered with a lowered baseline using smaller text.

    Almost every developer's favorite molecule is C8H10N4O2, also known as "caffeine."

    <sup>

    Specifies inline text which is to be displayed as superscript for solely typographical reasons. Superscripts are usually rendered with a raised baseline using smaller text.

    The total floor area of the mezzanine is 120m2, located on the 4th floor.

    <time>

    Represents a specific period in time. It may include the datetime attribute to translate dates into machine-readable format, allowing for better search engine results or custom features such as reminders.

    The concert starts at .

    <u>

    Represents a span of inline text which should be rendered in a way that indicates that it has a non-textual annotation. This is rendered by default as a single solid underline but may be altered using CSS.

    You could use this element to highlight speling mistakes, so the writer can corect them.

    <var>

    Represents the name of a variable in a mathematical expression or a programming context. It's typically presented using an italicized version of the current typeface, although that behavior is browser-dependent.

    The volume of a box is l × w × h, where l represents the length, w the width and h the height of the box.

    <wbr>

    Represents a word break opportunity—a position within text where the browser may optionally break a line, though its line-breaking rules would not otherwise create a break at that location.

    Fernstraßenbauprivatfinanzierungsgesetz

    Fernstraßenprivatfinanzierungsgesetz


    Image and multimedia

    HTML supports various multimedia resources such as images, audio, and video.

    <area> (Unstyled)

    Defines an area inside an image map that has predefined clickable areas. An image map allows geometric areas on an image to be associated with hyperlink.

    <audio>

    Used to embed sound content in documents. It may contain one or more audio sources, represented using the src attribute or the <source> element: the browser will choose the most suitable one. It can also be the destination for streamed media, using a MediaStream.

    <img>

    Embeds an image into the document.

    Placeholder image.

    <map> (Unstyled)

    Used with <area> elements to define an image map (a clickable link area).

    <track>

    Used as a child of the media elements, <audio> and <video>. It lets you specify timed text tracks (or time-based data), for example to automatically handle subtitles. The tracks are formatted in WebVTT format (.vtt files)—Web Video Text Tracks.

    <video>

    Embeds a media player which supports video playback into the document. You can also use <video> for audio content, but the <audio> element may provide a more appropriate user experience.


    Embedded content

    In addition to regular multimedia content, HTML can include a variety of other content, even if it's not always easy to interact with.

    <embed>

    Embeds external content at the specified point in the document. This content is provided by an external application or other source of interactive content such as a browser plug-in.

    <fencedframe> (Unstyled)

    Represents a nested browsing context, like <iframe> but with more native privacy features built in.

    <iframe>

    Represents a nested browsing context, embedding another HTML page into the current one.

    <object>

    Represents an external resource, which can be treated as an image, a nested browsing context, or a resource to be handled by a plugin.

    <picture>

    Contains zero or more <source> elements and one <img> element to offer alternative versions of an image for different display/device scenarios.

    Change the browser window width to see the image change.

    Placeholder image.

    <source>

    Specifies multiple media resources for the <picture>, the <audio> element, or the <video> element. It is a void element, meaning that it has no content and does not have a closing tag. It is commonly used to offer the same media content in multiple file formats in order to provide compatibility with a broad range of browsers given their differing support for image file formats and media file formats.

    Change the browser window width to see the image change.

    Placeholder image.

    SVG and MathML

    You can embed SVG and MathML content directly into HTML documents, using the <svg> and <math> elements.

    <svg>

    Container defining a new coordinate system and viewport. It is used as the outermost element of SVG documents, but it can also be used to embed an SVG fragment inside an SVG or HTML document.

    <math>

    The top-level element in MathML. Every valid MathML instance must be wrapped in it. In addition, you must not nest a second <math> element in another, but you can have an arbitrary number of other child elements in it.

    E = m c 2
    Mass-energy equivalence, Albert Einstein
    x = b b 2 4 a c 2 a
    The Quadratic Formula

    Scripting

    To create dynamic content and Web applications, HTML supports the use of scripting languages, most prominently JavaScript. Certain elements support this capability.

    <canvas> (Unstyled)

    Container element to use with either the canvas scripting API or the WebGL API to draw graphics and animations.

    <noscript> (Unstyled)

    Defines a section of HTML to be inserted if a script type on the page is unsupported or if scripting is currently turned off in the browser.

    <script> (Unstyled)

    Used to embed executable code or data; this is typically used to embed or refer to JavaScript code. The <script> element can also be used with other languages, such as WebGL's GLSL shader programming language and JSON.


    Demarcating edits

    These elements let you provide indications that specific parts of the text have been altered.

    <del>

    Represents a range of text that has been deleted from a document. This can be used when rendering "track changes" or source code diff information, for example. The <ins> element can be used for the opposite purpose: to indicate text that has been added to the document.

    The final site survey shows the foundation is 40 meters 42 meters from the north boundary.

    <ins>

    Represents a range of text that has been added to a document. You can use the <del> element to similarly represent a range of text that has been deleted from the document.

    Project Status: In Review Approved for Construction


    Table content

    The elements here are used to create and handle tabular data.

    <caption>

    Specifies the caption (or title) of a table.

    Project Material Schedule
    ID Material Description Supplier Status
    ST-01 Structural Steel - Grade 50 On-Site
    CON-04 High-Performance Concrete Delayed
    Total Line Items 2 Units

    <col>

    Defines one or more columns in a column group represented by its implicit or explicit parent <colgroup> element. The <col> element is only valid as a child of a <colgroup> element that has no span attribute defined.

    Mark Dimensions Status
    W-01 1200 x 1500 Ordered
    W-02 1800 x 2100 On-Site
    W-03 600 x 600 Backordered

    <colgroup>

    Defines a group of columns within a table.

    Hardware Specifications
    Component Material Finish
    Door Lever Solid Brass Brushed Chrome
    Hinges Stainless Steel Satin
    Strike Plate Steel Zinc Plated

    <table>

    Represents tabular data—that is, information presented in a two-dimensional table comprised of rows and columns of cells containing data.

    Task Lead Deadline
    Site Survey J. Wright Feb 15
    Soil Test M. Chen Feb 18
    Permit Filing S. Rossi Feb 20 Feb 22

    <tbody>

    Encapsulates a set of table rows (<tr> elements), indicating that they comprise the body of a table's (main) data.

    Concrete Strength Grades
    Grade C20 20 N/mm² Domestic Floors
    Grade C30 30 N/mm² Pavement & Drives
    Grade C40 40 N/mm² Commercial Foundations

    <td>

    A child of the <tr> element, it defines a cell of a table that contains data.

    Floor Finish Schedule
    Room Finish Installation Notes
    101 Polished Conc. Sealant to be applied in two coats minimum.
    102 Oak Timber Acclimatize on-site for 48 hours prior to install.

    <tfoot>

    Encapsulates a set of table rows (<tr> elements), indicating that they comprise the foot of a table with information about the table's columns. This is usually a summary of the columns, e.g., a sum of the given numbers in a column.

    Labour Hours: Feb 12
    Trade Hours
    Carpentry 16
    Electrical 8
    Total 24

    <th>

    A child of the <tr> element, it defines a cell as the header of a group of table cells. The nature of this group can be explicitly defined by the scope and headers attributes.

    Formula Name Notation Primary Variable
    Mass-Energy E = mc² Energy (E)

    <thead>

    Encapsulates a set of table rows (<tr> elements), indicating that they comprise the head of a table with information about the table's columns. This is usually in the form of column headers (<th> elements).

    Unit 04
    Width Height Depth
    1200mm 2400mm 450mm

    <tr>

    Defines a row of cells in a table. The row's cells can then be established using a mix of <td> (data cell) and <th> (header cell) elements.

    Consultant Contact
    Lead Arch Ext. 402
    Structural Ext. 509

    Forms

    HTML provides several elements that can be used together to create forms that the user can fill out and submit to the website or application. Further information about this available in the HTML forms guide.

    <button>

    An interactive element activated by a user with a mouse, keyboard, finger, voice command, or other assistive technology. Once activated, it performs an action, such as submitting a form or opening a dialog.

    <datalist>

    Contains a set of <option> elements that represent the permissible or recommended options available to choose from within other controls.

    <fieldset>

    Used to group several controls as well as labels (<label>) within a web form.

    Choose your favorite monster

    <form>

    Represents a document section containing interactive controls for submitting information.

    Project Details
    System Specs

    <input>

    Used to create interactive controls for web-based forms to accept data from the user; a wide variety of types of input data and control widgets are available, depending on the device and user agent. The <input> element is one of the most powerful and complex in all of HTML due to the sheer number of combinations of input types and attributes.

    checkbox
    color
    radio:

    <label>

    Represents a caption for an item in a user interface.

    <legend>

    Represents a caption for the content of its parent <fieldset>.

    Mathematical Constraints

    <meter>

    Represents either a scalar value within a known range or a fractional value.

    <optgroup>

    Creates a grouping of options within a <select> element.

    <option>

    Used to define an item contained in a <select>, an <optgroup>, or a <datalist> element. As such, <option> can represent menu items in popups and other lists of items in an HTML document.

    <output> (Unstyled)

    Container element into which a site or app can inject the results of a calculation or the outcome of a user action.

    <progress>

    Displays an indicator showing the completion progress of a task, typically displayed as a progress bar.

    <select>

    Represents a control that provides a menu of options.

    <selectedcontent> (Unstyled)

    Displays the content of the currently selected <option> inside a closed <select> element.

    <textarea>

    Represents a multi-line plain-text editing control, useful when you want to allow users to enter a sizeable amount of free-form text, for example, a comment on a review or feedback form.


    Interactive elements

    HTML offers a selection of elements that help to create interactive user interface objects.

    <details>

    Creates a disclosure widget in which information is visible only when the widget is toggled into an "open" state. A summary or label must be provided using the <summary> element.

    Advanced Structural Calculations

    These values are calculated based on the 2026 Architectural Standards.

    Load Distribution
    Details

    Something small enough to escape casual notice.

    File Properties
    File Properties
    Created 2026-02-14
    Author Chief Architect
    Revision v2.4.0
    Export Blueprint

    <dialog> (Unstyled)

    Represents a dialog box or other interactive component, such as a dismissible alert, inspector, or subwindow.

    <geolocation> (Unstyled)

    Creates an interactive control for the user to share their geolocation data with the page.

    <summary>

    Specifies a summary, caption, or legend for a <details> element's disclosure box. Clicking the <summary> element toggles the state of the parent <details> element open and closed.

    What is classless CSS?

    It is a CSS file that styles standard HTML elements (like h1, p, and table) automatically without requiring you to add classes to your HTML tags.

    Documentation Status
    • Installation: Complete
    • Configuration: Pending
    • Deployment: Not started
    View technical logs
    v1.0.4: Database handshake verified.
    v1.0.5: SSL certificates renewed.
    v1.0.6: Assets symlinked to production.

    Web Components

    Web Components is an HTML-related technology that makes it possible to, essentially, create and use custom elements as if it were regular HTML. In addition, you can create custom versions of standard HTML elements.

    <slot> (Unstyled)

    Part of the Web Components technology suite, this element is a placeholder inside a web component that you can fill with your own markup, which lets you create separate DOM trees and present them together.

    <template> (Unstyled)

    A mechanism for holding HTML that is not to be rendered immediately when a page is loaded but may be instantiated subsequently during runtime using JavaScript.