Fern selectors use Tailwind CSS utilities and CSS custom properties. This page is a reference of all .fern-* selectors for customizing your documentation site.
Selectors for page layout, backgrounds, and headings.
Fixed background image.
Primary page heading (h1).
Page layout container.
Guide page layout.
API Reference layout with two-column grid.
Overview page layout.
Changelog page layout.
Selectors for the site header, tabs, and mobile menu.
Site header container.
Header navigation tabs (desktop only).
Header logo container.
Header search input (desktop only).
Selectors for sidebar navigation and tabs.
Top of sidebar.
Sidebar section heading.
Sidebar heading text.
Sidebar link.
Sidebar link text.
Long title marquee animation.
Grouped sidebar items.
Sidebar tab navigation.
Selectors for breadcrumb navigation.
Breadcrumb navigation.
Breadcrumb link or text.
Breadcrumb separator.
Selectors for buttons.
Button with variants.
Variants:
.minimal - Transparent background with subtle hover.filled - Solid background color.outlined - Border with transparent background.primary - Accent color variant.success - Green color variant.warning - Amber color variant.danger - Red color variantSize modifiers:
.small - Smaller button (height: 1.75rem on desktop, 1.5rem on mobile).large - Larger button (height: 2.75rem on desktop, 2.5rem on mobile).square - Square button with equal width and heightButton content wrapper.
Button text.
Button group.
Copy button for code blocks.
Expand button for maxLines code blocks.
Page action buttons (edit, feedback, share).
Variants:
.fern-toolbar - Removes the border styling for a toolbar-style appearanceSelectors for cards.
Card container.
Variants:
.interactive - Adds hover effects.elevated - Elevated appearance with accent border.active - Active state stylingSelectors for form inputs and controls.
Text input.
Input container with focus ring.
Input icon.
Right-side input element.
Input clear button.
Multi-line text input.
Textarea container.
Checkbox label.
Checkbox input.
Checked indicator.
Radio button group.
Radio label.
Radio button input.
Selected indicator.
Segmented toggle control.
Numeric input with stepper buttons.
Numeric input stepper button.
Selectors for dropdowns and the product selector.
Dropdown menu container.
Dropdown menu item.
Dropdown selection indicator.
Selection item.
Selection item icon.
Selection item title.
Selection item end icon.
Product selector. See styles.css for examples.
Product selector radio group. See styles.css for examples.
Selectors for accordions.
Accordion container.
Accordion item.
Expand/collapse trigger.
Expand/collapse arrow.
Accordion trigger title.
Selectors for scrollable areas.
Scrollable area container.
Scroll viewport.
Scrollbar.
Scrollbar thumb.
Scrollbar corner.
Selectors for badges and HTTP method tags.
Badge for labels, status, and HTTP methods.
Selectors for links, callouts, steps, and tables.
Link with external icon and hover underline.
Callout with intent-matched colors.
Intent variants:
[data-intent="info"] - Gray/neutral (default)[data-intent="warning"] - Amber/yellow[data-intent="success"] - Green[data-intent="error"] - Red[data-intent="note"] - Blue[data-intent="launch"] - Accent color[data-intent="tip"] - Green[data-intent="check"] - GreenIndent with vertical guide line.
Steps container.
Single step.
Anchor for deep linking.
Table container.
Table with .sticky support for sticky headers.
Selectors for changelog filter UI. Only on changelog pages with tags.
Filter dropdown trigger button.
Filter button text.
Filter button chevron.
Filter dropdown item.
Filter badge base class.
Selected filter badge.
Unselected filter badge.
Filter dropdown checkmark.
Selectors for API Reference components.
API property container.
API property header.
API property name.
API property metadata (type, required).
API property constraint.
Selectors for icons, tooltips, and other elements.
Highlighted text.
Inline icon (adapts to theme).
Tooltip trigger with underline.
Tooltip content.
File type icon.
Collapsible child element.
RSS feed button.
Selectors for changelog pages.
Changelog page container.
Variants:
.full-width - Full-width layout with sidebar date displayChangelog entry.
Changelog date.
Changelog content area.
Changelog entry label.