Version: 4.6.0

UI Page Theming

Horizon Design System theming reference for ServiceNow UI Pages, covering design foundations, layout patterns, controls, and component styling.

Theming: Horizon Design System Foundations

The Horizon Design System defines foundational rules for generating ServiceNow-compliant UIs using HTML, CSS, and design tokens (CSS custom properties).

Core Principles

Fluid: UIs MUST adapt seamlessly to varying contexts. Use relative units (rem, %, auto) and spacing tokens, not fixed pixels.
Symphonic: Components MUST visually harmonize. Consistent radius, shadows, and typography ensure unified experience.
Accessible: All UIs MUST comply with WCAG 2.1 AA: text contrast >= 4.5:1, visible focus states, keyboard navigation, semantic HTML.

Color Roles

primary -- intended for primary actions or important UI elements
secondary -- complementary color to the primary colors
primary background -- default theme background
secondary background -- strong division between sections (use sparingly)
text variables -- palette for written content like sentences, paragraphs, or captions
Semantic colors: alert, warning, positive -- convey feedback, status, or urgency

Accessibility Standards

All interactive elements MUST have distinct states: base, hover, active, focus-visible, disabled
Focus rings MUST use inset shadows or outlines (no layout reflow)
Screen-reader labels MUST exist for all actionable elements
Landmarks (<header>, <nav>, <main>, <footer>) SHOULD be used

Foundation Token Patterns

Property	Token Pattern	Available Values
Spacing	`--now-static-space--{size}`	xxs (0.125rem), xs (0.25rem), sm (0.5rem), md (0.75rem), lg (1rem), xl (1.5rem), xxl (2rem), 3xl (2.5rem)
Drop Shadows	`--now-static-drop-shadow--{size}`	sm, md, lg, xl, xxl
Border Radius	`--now-static-border-radius--{size}`	sm (0.125rem), md (0.25rem), lg (0.5rem)
Font Sizes	`--now-static-font-size--{size}`	sm (0.75rem), md (1rem), lg (1.25rem), xl (1.5rem)
Line Height	`--now-static-line-height`	1.25 (unitless)
Font Family	`--now-font-family`	Lato, Arial, sans-serif

Semantic Token Categories

Element Type	Token Category	Example
Buttons, CTAs	`actionable`	`--now-actionable--primary--background-color`
Inputs, Checkboxes	`form-control`	`--now-form-control-input--primary--border-color`
Containers, Cards	`container`	`--now-container-card--background-color-alpha`
Windows, Modals	`window`	`--now-window--border-color`
Menus, Lists	`menu`	`--now-menu-list--primary--background-color`
Navigation	`navigation`	`--now-navigation-page_tabs--primary--background-color`
Alerts, Banners	`messaging`	`--now-messaging--primary_warning--border-color`
Status Indicators	`indicator`	`--now-indicator--primary_critical--background-color`
Typography	`display-type`	`--now-display-type_label--font-weight`

Token Integrity Rules

Each visual property MUST use a valid design token
Tokens MUST belong to correct semantic category
Fallbacks MUST follow chained var() structure
Colors MUST be wrapped with rgb() or rgba()
No hard-coded color values -- use tokens

/* Correct fallback chain */
var(--now-actionable--primary--background-color, var(--now-color--primary-1, 0,128,163))

/* Correct color wrapping */
background-color: rgb(var(--now-color_background--primary, 255, 255, 255));

Alias Layer

Provide stable, reusable names mapping to instance tokens:

:root {
  /* Surfaces & borders */
  --snx-color-surface: rgb(var(--now-container--color, 255, 255, 255));
  --snx-color-surface-alt: rgb(var(--now-heading--header-primary--color, 245, 247, 249));
  --snx-color-border: rgb(var(--now-container--border-color, 207, 213, 215));

  /* Text */
  --snx-color-text: rgb(var(--now-color_text--primary, 16, 23, 26));
  --snx-color-text-muted: rgb(var(--now-color_text--secondary, 75, 85, 89));

  /* Actions & focus */
  --snx-color-primary: rgb(var(--now-actionable--primary--background-color, 0, 128, 163));
  --snx-color-on-primary: rgb(var(--now-actionable_label--primary--color, 255, 255, 255));
  --snx-color-focus: rgb(var(--now-color_focus-ring, 53, 147, 37));

  /* Spacing */
  --snx-space-inner: var(--now-static-space--md, 0.75rem);
  --snx-space-outer: var(--now-static-space--lg, 1rem);

  /* Border radius - component-specific */
  --snx-radius-button: var(--now-actionable--border-radius, 6px);
  --snx-radius-input: var(--now-form-control-input--primary--border-radius, 2px);
  --snx-radius-container: var(--now-container--border-radius, 8px);

  /* Typography */
  --snx-font-body: var(--now-font-family, system-ui, sans-serif);
  --snx-line-height: var(--now-static-line-height, 1.25);
}

Rules for aliases: NEVER create generic aliases that ignore component requirements. ALWAYS use component-specific aliases. Aliases MUST remain stable between generations.

Dark Mode

Each token has light and dark mode values. The theme system handles switching automatically:

/* Token automatically switches between light/dark */
background-color: rgb(var(--now-container--color, 255, 255, 255));
color: rgb(var(--now-color_text--primary, 16, 23, 26));

Browser Default Resets

When using base HTML elements, ALWAYS reset browser defaults that conflict with design tokens:

.form {
  display: grid;
  margin: 0;
  padding: 0;
  border: none;
  grid-template-columns: 1fr 1fr;
  gap: var(--now-static-space--lg, 1rem);
}

Theming: Layout Patterns

Cards

Cards present grouped content in elevated surfaces. They MUST contain header, body, and optional footer slots.

.card {
  background-color: rgb(var(--now-color_background--secondary, 245, 246, 247));
  border: 1px solid rgb(var(--now-container-card--border-color, 207, 213, 215));
  border-radius: var(--now-container-card--border-radius, 8px);
  box-shadow: var(--now-static-drop-shadow--sm);
  display: flex;
  flex-direction: column;
  overflow: hidden;
}

.card__header {
  padding: var(--now-static-space--lg, 1rem);
  border-bottom: 1px solid rgb(var(--now-container-card--border-color, 207, 213, 215));
  font-weight: 600;
  color: rgb(var(--now-color_text--primary, 16, 23, 26));
  background-color: rgb(var(--now-container--color, 255, 255, 255));
}

.card__body {
  padding: var(--now-static-space--lg, 1rem);
  color: rgb(var(--now-color_text--primary, 16, 23, 26));
  flex: 1;
}

.card__footer {
  padding: var(--now-static-space--lg, 1rem);
  border-top: 1px solid rgb(var(--now-container-card--border-color, 207, 213, 215));
  display: flex;
  justify-content: flex-end;
  gap: var(--now-static-space--sm, 0.5rem);
}

Modals and Dialogs

Modals use window category tokens. They MUST include header, body, and optional footer regions. Focus MUST trap within modal.

.modal-overlay {
  position: fixed;
  inset: 0;
  background-color: rgba(
    var(--now-window_overlay--background-color, 0, 0, 0),
    var(--now-window_overlay--background-color-alpha, 0.5)
  );
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 1000;
}

.modal {
  background-color: rgb(var(--now-window--background-color, 255, 255, 255));
  border: 1px solid rgb(var(--now-window--border-color, 207, 213, 215));
  border-radius: var(--now-window--border-radius, 8px);
  width: 90%;
  max-width: 600px;
  max-height: 90vh;
  display: flex;
  flex-direction: column;
  box-shadow: var(--now-static-drop-shadow--lg);
}

.modal__header {
  padding: var(--now-static-space--lg, 1rem);
  border-bottom: 1px solid rgb(var(--now-window--border-color, 207, 213, 215));
  font-weight: var(--now-window_header--font-weight, 600);
  color: rgb(var(--now-color_text--primary, 16, 23, 26));
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.modal__body {
  padding: var(--now-static-space--lg, 1rem);
  overflow-y: auto;
  flex: 1;
  color: rgb(var(--now-color_text--primary, 16, 23, 26));
}

.modal__footer {
  padding: var(--now-static-space--lg, 1rem);
  border-top: 1px solid rgb(var(--now-window--border-color, 207, 213, 215));
  display: flex;
  justify-content: flex-end;
  gap: var(--now-static-space--sm, 0.5rem);
}

Forms Layout

.form {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--now-static-space--lg, 1rem);
}

@media (max-width: 768px) {
  .form {
    grid-template-columns: 1fr;
  }
}

.form__label {
  font-weight: var(--now-form-control_label--primary--font-weight, 600);
  color: rgb(var(--now-form-control_label--primary--color, 16, 23, 26));
  margin-bottom: var(--now-static-space--sm, 0.5rem);
  font-size: 0.875rem;
}

.form__input {
  height: calc(1rem + var(--now-form-field--scale-size-block, 1) * 2rem / 2);
  padding: 0 var(--now-static-space--md, 0.75rem);
  border: 1px solid rgb(var(--now-form-control-input--primary--border-color, 207, 213, 215));
  border-radius: var(--now-form-control-input--primary--border-radius, 2px);
  background-color: rgb(var(--now-input--background-color, 255, 255, 255));
  color: rgb(var(--now-color_text--primary, 16, 23, 26));
}

Lists

.list {
  border: 1px solid rgb(var(--now-container--border-color, 207, 213, 215));
  border-radius: var(--now-container--border-radius, 8px);
  overflow: hidden;
}

.list__header {
  background-color: rgb(var(--now-menu-list--primary--background-color, 245, 247, 249));
  font-weight: 600;
  color: rgb(var(--now-color_text--primary, 16, 23, 26));
  border-bottom: 1px solid rgb(var(--now-container--border-color, 207, 213, 215));
}

.list__row {
  border-bottom: 1px solid rgb(var(--now-container--border-color, 207, 213, 215));
  background-color: rgb(var(--now-container--color, 255, 255, 255));
  color: rgb(var(--now-color_text--primary, 16, 23, 26));
}

.list__row:hover {
  background-color: rgb(var(--now-menu-list--primary--background-color--hover, 235, 237, 239));
}

Tables

Tables MUST use semantic HTML (<table>, <thead>, <tbody>, <tr>, <td>, <th>).

.table {
  width: 100%;
  border-collapse: collapse;
  border: 1px solid rgb(var(--now-container--border-color, 207, 213, 215));
}

.table th, .table td {
  padding: var(--now-static-space--md, 0.75rem) var(--now-static-space--lg, 1rem);
  border-bottom: 1px solid rgb(var(--now-container--border-color, 207, 213, 215));
  text-align: left;
}

.table thead {
  background-color: rgb(var(--now-color_background--tertiary, 226, 229, 231));
  font-weight: 600;
}

.table tbody tr {
  background-color: rgb(var(--now-color_background--primary, 255, 255, 255));
}

.table tbody tr:hover {
  background-color: rgba(var(--now-color--primary-1, 245, 246, 247), var(--now-opacity--least, 0.1));
}

Theming: Controls

Buttons

Buttons use the actionable token category. All controls MUST support states: base, hover, active, focus-visible, disabled.

.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--now-static-space--sm, 0.5rem);
  min-block-size: calc(1rem + var(--now-button--scale-size-block, 1) * 2rem / 2);
  padding-inline: calc(1rem * var(--now-button--scale-size-inline, 1));
  border: 1px solid transparent;
  border-radius: var(--now-actionable--border-radius, 6px);
  font-family: var(--now-font-family, system-ui, sans-serif);
  font-size: 1rem;
  cursor: pointer;
  transition: background-color 100ms linear;
}

.btn--primary {
  background-color: rgb(var(--now-actionable--primary--background-color, 0, 128, 163));
  color: rgb(var(--now-actionable_label--primary--color, 255, 255, 255));
  border-color: rgb(var(--now-actionable--primary--border-color, 0, 128, 163));
}

.btn--primary:hover {
  background-color: rgb(var(--now-actionable--primary--background-color--hover, 0, 138, 173));
}

.btn--primary:focus-visible {
  box-shadow: inset 0 0 0 2px rgb(var(--now-color_focus-ring_shadow, 53, 147, 37));
}

.btn--primary:disabled {
  opacity: 0.4;
  cursor: not-allowed;
}

Secondary/Tertiary Button Alpha Channel (CRITICAL): Secondary/tertiary buttons use RGBA with alpha for transparency, NOT solid RGB:

.btn--secondary {
  background-color: rgba(
    var(--now-actionable--secondary--background-color, 0, 113, 143),
    var(--now-actionable--background-color-alpha, 0)
  );
}

.btn--secondary:hover {
  background-color: rgba(
    var(--now-actionable--secondary--background-color--hover, 0, 76, 97),
    var(--now-actionable--background-color-alpha--hover, 0.08)
  );
}

Input Fields

input[type="text"], input[type="email"], input[type="number"], textarea {
  height: calc(1rem + var(--now-form-field--scale-size-block, 1) * 2rem / 2);
  padding: 0 var(--now-static-space--md, 0.75rem);
  border: 1px solid rgb(var(--now-form-control-input--primary--border-color, 115, 127, 132));
  border-radius: var(--now-form-control-input--primary--border-radius, 2px);
  background-color: rgb(var(--now-input--background-color, 255, 255, 255));
  color: rgb(var(--now-color_text--primary, 16, 23, 26));
}

input:focus-visible {
  outline: none;
  border-color: rgb(var(--now-form-control-input--primary--border-color--focus, 53, 147, 37));
  box-shadow: inset 0 0 0 1px rgb(var(--now-form-control_focus-ring--primary--color, 53, 147, 37));
}

Focus states MUST use inset box-shadow or outline (no border width changes that cause layout reflow).

Checkboxes and Radio Buttons

Checkboxes use form-control-input-selection--primary tokens. Radio buttons use form-control-input-selection--secondary tokens.

Toggles

Track and handle derive from distinct subcategories (form-control_track, form-control_handle).

Pills and Chips

Background and border derive from pill tokens. Remove icons MUST inherit text color via currentColor.

Theming: Components

Severity Variant Reference

All messaging, alert, and indicator components use these semantic variants:

Display Name	Token Variant	Use For
Success	`positive`	Successful operations, valid states
Error	`critical`	Errors, failures, urgent issues
Warning	`warning`	Warnings, cautions
Info	`info`	Informational messages

ALWAYS use positive, critical, warning, info -- NEVER "success", "error", or "informational".

Alerts and Banners

Alert components use alert tokens for backgrounds and borders. Text color fallback chain: --now-alert--color -> --now-messaging_label--primary--color -> --now-color_text--primary.

.alert--warning {
  background-color: rgb(var(--now-alert--warning--background-color, 239, 224, 176));
  border: 1px solid rgb(var(--now-alert--warning--border-color, 221, 182, 101));
  color: rgb(var(
    --now-alert--color,
    var(--now-messaging_label--primary--color, var(--now-color_text--primary, 16, 23, 26))
  ));
}

Toast Notifications MUST use --now-container-card--background-color (NOT --now-container--color) for proper dark mode inversion.

Tabs

Tabs use --now-tabs--* design tokens. Active tabs show bottom border only (not full border). Tabs MUST NOT have gaps between them. Tabs MUST NEVER have vertical scrolling.

State	Border	Font Weight
Base	transparent bottom	normal
Hover	focus-ring bottom	normal
Active	focus-ring bottom	600

.tabs {
  display: flex;
  border-bottom: 1px solid rgb(var(--now-container--border-color, 207, 213, 215));
  overflow-x: auto;
  overflow-y: hidden;
}

.tab {
  padding: 0.75rem 1rem;
  color: rgb(var(--now-tabs--color, 16, 23, 26));
  cursor: pointer;
  border: none;
  border-bottom: 0.125rem solid transparent;
  background-color: rgba(var(--now-tabs--background-color, 255, 255, 255), var(--now-tabs--background-color-alpha, 0));
  border-radius: 0;
  margin-bottom: -1px;
}

.tab--active {
  border-bottom-color: rgb(var(--now-color_focus-ring, var(--now-color--secondary-1, 0, 128, 163)));
  font-weight: 600;
}

Use content-tree tokens (NOT navigation-sidebar) for proper contrast and dark mode support.

.sidenav {
  background-color: rgb(var(--now-content-tree--background-color, 255, 255, 255));
  width: 240px;
  border: 1px solid rgb(var(--now-container-card--border-color, 207, 213, 215));
  border-radius: 6px;
}

.sidenav__item {
  display: flex;
  align-items: center;
  padding: 0.75rem 1rem;
  color: rgb(var(--now-content-tree--color, 16, 23, 26));
  border-left: 4px solid transparent;
}

.sidenav__item--active {
  background-color: rgb(var(--now-content-tree--background-color--selected, 224, 234, 222));
  border-left-color: rgb(var(--now-color--primary-1, 0, 128, 163));
  font-weight: 600;
}

Badges and Indicators

Badge text MUST use --now-indicator_label--{variant}--color (note _label subcategory), NOT base indicator color.

.badge--positive {
  background-color: rgb(var(--now-indicator--primary_positive--background-color, 62, 134, 0));
  color: rgb(var(--now-indicator_label--primary_positive--color, 255, 255, 255));
  border: 1px solid rgb(var(--now-indicator--primary_positive--border-color, 48, 103, 0));
}

.badge--critical {
  background-color: rgb(var(--now-indicator--primary_critical--background-color, 229, 34, 57));
  color: rgb(var(--now-indicator_label--primary_critical--color, 255, 255, 255));
}

Progress Indicators

.progress {
  width: 100%;
  height: 0.5rem;
  background-color: rgb(var(--now-progress-bar--background-color, 240, 242, 243));
  border-radius: var(--now-static-border-radius--lg, 0.5rem);
  overflow: hidden;
}

.progress__fill {
  height: 100%;
  background-color: rgb(var(--now-progress-bar_path--initial--background-color, 0, 128, 163));
  transition: width 200ms ease;
}

.spinner {
  border: 2px solid rgba(var(--now-loading_indicator--primary--color, 0, 128, 163), 0.2);
  border-top-color: rgb(var(--now-loading_indicator--primary--color, 0, 128, 163));
  border-radius: 50%;
  width: 1.5rem;
  height: 1.5rem;
  animation: spin 1s linear infinite;
}

@keyframes spin {
  100% { transform: rotate(360deg); }
}

Stepper (Progress Indicator)

Step indicators use circular shapes with consistent sizing (2rem diameter). Completed steps use checkmark SVG icon (never unicode). Icons MUST use fill: currentColor.

State	Tokens
Completed	`stepper_step--done` (green background, green border)
Active	`stepper_step--partial` (white background, green border)
Incomplete	`stepper_step--none` (white background, gray border)

Pagination

Pagination buttons use bare/borderless style. Navigation arrows MUST use SVG icons, never unicode characters. Active page MUST have distinct background and bold font weight.

Expandable/Collapsible UI

Icons MUST use SVG, never unicode characters. Icon size MUST be 1rem. Rotation animation uses CSS transforms. Icons use fill: currentColor to inherit text color.

Extrapolation Guidelines

When components are not explicitly defined in the Horizon system, extrapolate using established philosophies, token categories, spacing rhythm, and state logic. Select tokens from the closest semantic category. Extrapolated interactive elements MUST implement the standard state set: base, hover, active, focus-visible, disabled.

New Element	Recommended Analogue	Token Category
Split button	Button + Menu	`actionable` for trigger; `menu` for list
Command palette	Menu/Dialog hybrid	`menu` for list; `window` for container
Inline tag editor	Pill/Chip	`form-control-pill`
Empty state panel	Card + Messaging	`container` for surface; `messaging` for accent

Theming: Horizon Design System Foundations​

Core Principles​

Color Roles​

Accessibility Standards​

Foundation Token Patterns​

Semantic Token Categories​

Token Integrity Rules​

Alias Layer​

Dark Mode​

Browser Default Resets​

Theming: Layout Patterns​

Cards​

Modals and Dialogs​

Forms Layout​

Lists​

Tables​

Theming: Controls​

Buttons​

Input Fields​

Checkboxes and Radio Buttons​

Toggles​

Pills and Chips​

Theming: Components​

Severity Variant Reference​

Alerts and Banners​

Tabs​

Side Navigation​

Badges and Indicators​

Progress Indicators​

Stepper (Progress Indicator)​

Pagination​

Expandable/Collapsible UI​

Extrapolation Guidelines​