Acquia FE Specialist (D10) key terms

A browser-built tree representation of an HTML page, where every element, attribute, and text node is an object that scripts can read and modify after the page loads.

A weighting system browsers use to decide which conflicting CSS rule wins, based on counts of IDs, classes, attributes, and element selectors in each selector.

The rules that determine which declared styles apply to an element: source order, specificity, and importance resolve conflicts, while inheritable properties flow from parent to child.

Markup that uses elements matching the meaning of the content, such as header, nav, main, and article, giving structure that assistive technology and search engines can interpret.

A build strategy that starts with working semantic HTML and layers styling and scripting on top, so core content and tasks remain usable when CSS or JavaScript fails.

A strategy that builds a full-featured experience first and then adds fallbacks so older browsers or failed features still deliver something usable.

The exchange in which a browser sends a request with a method, URL, and headers, and the server returns a status code, headers, and a body such as an HTML page.

An approach that uses fluid grids, flexible images, and media queries so one codebase adapts layout and typography to different viewport sizes and devices.

A CSS at-rule that applies a block of styles only when conditions about viewport width, orientation, resolution, or user preferences are met.

A chosen viewport width or condition at which a layout switches to a different arrangement, usually defined in CSS media queries or a theme's configuration.

A meta element in the document head that tells mobile browsers how to scale the page, commonly set to width=device-width, initial-scale=1 for responsive layouts.

A named entry in a theme's hook definitions, such as hook_node or hook_block, that declares variables and a template suggestion so Drupal can render a specific piece of output.

The Drupal hook where a module or theme registers theme hooks, declaring which variables they accept and which Twig template or render element implements them.

An ordered list of more specific template filenames, such as node--article--teaser.html.twig, that Drupal tries before falling back to a base template.

A Drupal alter hook that lets a module or theme add, remove, or reorder Twig template suggestions for a given theme hook before Drupal selects a template.

A theme or module function named for a theme hook, such as mytheme_preprocess_node, that prepares or adds variables before the matching Twig template renders.

A theme another theme declares as its parent, inheriting its templates, libraries, and assets so the child theme only overrides what it needs.

A theme whose info file names a base theme, allowing it to inherit templates and assets while overriding selected files and configuration for a specific site.

The required metadata file in a Drupal theme that declares its name, type, core version compatibility, base theme, libraries, and regions.

A THEME.libraries.yml entry that names a bundle of CSS and JavaScript assets with dependencies, versions, and loading options so Drupal can attach it to pages or components.

A structured PHP array describing output to be rendered, with keys for the element type, properties, child elements, and cache metadata.

The cacheability information attached to a render array, including cache tags, contexts, and max-age, which tells Drupal when cached output must be invalidated.

The PHP templating engine Drupal uses for front-end output, offering a concise syntax for printing variables, control structures, filters, and template inheritance.

The double-curly-brace syntax that outputs a variable or expression into the rendered template, for example printing a node's label.

A pipe-applied modifier in Twig that transforms a value, such as converting text with the t filter for translation or joining items with the join filter.

A Twig safety feature that HTML-escapes printed output by default, preventing injected markup from executing unless output is explicitly marked safe.

A Twig mechanism where a template extends a parent and fills named blocks, letting child templates override parts of a shared layout without duplicating markup.

A Twig tag that renders another template inside the current one, optionally passing variables, so reusable fragments can be shared across templates.

A Twig tag that includes another template while also allowing the including template to override blocks defined inside it, combining inclusion with inheritance.

The practice of wrapping user-facing strings in Twig's t filter or trans tag so Drupal's interface translation system can localize the text.

A Drupal development setting that adds HTML comments listing candidate template suggestions and active templates, helping developers identify which Twig file to override.

Drupal's cache of theme hook definitions and discovered template files, rebuilt when hooks or templates change so rendering can resolve templates efficiently.

A copy of a base or module Twig template placed in a theme, named to match a suggestion, so the theme controls markup without altering contributed code.

A Drupal performance setting that combines multiple CSS or JavaScript files into fewer bundles, reducing the number of HTTP requests a page makes.

A target limit on metrics such as page weight, request count, or load time that guides development decisions and flags regressions before release.

Deferring the loading of offscreen resources, such as images or iframes, until they approach the viewport, reducing initial bytes and improving perceived load speed.

Serving appropriately sized image files for each device using srcset and sizes attributes or picture elements, so small screens avoid downloading oversized images.

The minimal styles needed to render above-the-fold content, which can be inlined in the document head so the first paint does not wait for a full stylesheet.

The sequence of steps a browser takes to turn HTML, CSS, and JavaScript into painted pixels, including building the DOM and CSSOM and computing layout.

Response headers such as Cache-Control and ETag that tell browsers and proxies how long a resource may be reused and how to validate it later.

An identifier attached to cached output or a cache entry so that Drupal can invalidate everything depending on changed content when that content is updated.

Extra HTML attributes that describe roles, states, and properties for assistive technology when native semantic elements cannot express the needed meaning.

Page areas identified by semantic elements or ARIA roles, such as banner, navigation, main, and contentinfo, that let screen reader users jump between sections.

A numeric measure of luminance difference between foreground and background colors, used to check whether text meets accessibility thresholds such as WCAG AA.

The visible styling a browser or theme applies to the currently focused element, which must remain perceivable so keyboard users can track their position.

A vulnerability where untrusted input reaches the page as executable markup or script, which Drupal mitigates through output escaping and Twig's default autoescaping.