Nice Select

This post pushes customizable <select> to an extreme. I think it turned out nice.

It's mostly CSS! A li'l JS sprinkle just to position the ::picker() and the selected option together; the JS is nice to have, CSS does the real work.

superellipse forced colors light/dark theme slick scrollbar scroll driven animations scroll-state stuck query scroll-state scrollable query overscroll behavior smooth scroll RTL support text-box trim spring easing anchor & anchor fallbacks color-mix()

Chrome only atm, and I keep mobile with the native select. Still cool!

Try it

Core Architecture #

This component builds on the new appearance: base-select foundation, combining native accessibility with sweet visual control. Progressive enhancement ensures the custom experience only loads on capable devices.

• appearance: base-select
  unlocks full customization of native <select> elements while retaining browser controlled accessibility and keyboard navigation
• Conditional enhancement
  Only enables custom styling for devices with hover and fine pointer (@media (hover) and (pointer: fine))
• JavaScript + CSS hybrid
  JS calculates an anchor offset for alignment while CSS handles all visual presentation and animation

Alignment & Positioning #

Anchor positioning plus some special JS sauce to write an inline CSS variable unlocks the picker to position near the selected option (obviously this can't work at the viewport edges). This creates a pleasant morphing effect that feels connected.

• CSS Anchor Positioning
  Picker uses anchor(start) to position relative to the trigger button
• Selected option alignment
  When dropdown opens, the currently selected option aligns vertically with the button text via --_select-anchor-offset custom property
• Syncs transform-origin
  With 50% var(--_select-anchor-offset) ensures scale animations line up better with the selected option's position
• Anchor fallbacks with position-try
flip-block, flip-inline automatically repositions the anchor position if the picker would overflow the viewport

Animation & Transitions #

Scale effects with spring physics to scroll-driven option reveals, every interaction respects user motion preferences while providing rich feedback.

• @starting-style
  Defines entry animation initial state for the popover
• Spring easing
  Uses Open Props --ease-spring-3 for playful, physics-based motion on scale and rotation
• Discrete property transitions
  display and overlay use allow-discrete for proper ::picker() popover animation support
• Chevron rotation
  ::picker-icon rotates 180° on open with spring easing
• Scroll-driven option fade-in
  Options animate in from the bottom using animation-timeline: view()
• Respects reduced motion
  Animations and transitions wrapped in @media (prefers-reduced-motion: no-preference)
• Button press feedback
  Active state scales down to 0.98 for tactile feedback
• Open state button feedback
  Select scales up to 1.04 when :open, scaling back down on close with a soft bounce

Theming & Color Handling #

Automatic light/dark adaptation leverages system colors and modern color functions for seamless theme switching. Definitely check the support for light/dark forced colors too, a really great way to debug spacing and skeletal aspects of the UI.

• color-scheme: light dark
  Enables automatic system color adaptation
• light-dark() function
  Used for backgrounds that need different light/dark values
• System colors
  Canvas, CanvasText, Highlight, HighlightText for semantic, colors
• color-mix()
  Creates semi-transparent overlays and borders
• Data URI icons
  Chevron and checkmark icons embedded as SVG data URIs with variants for each color scheme
• Forced colors support
  @media (forced-colors: active) provides high-contrast mode adaptations (even the sticky scroll state respects this!)

Layout & Spacing #

Logical properties enable true internationalization with automatic RTL support, while text-box trim delivers pixel-perfect vertical alignment. Custom properties create a flexible design token system.

• CSS Custom Properties design tokens
  All spacing, sizes, and timing values defined as --_select-* variables
• Logical properties throughout
  inline-size, block-size, inset-block-start, margin-inline, padding-block for full RTL support
• text-box: trim-both cap alphabetic
  Precise vertical text alignment in legends
• Flexible option content
  Options use flexbox with gap for icon + text layout
• Checkmark auto-positioned
  order: 2 and margin-inline-start: auto pushes checkmark to end of option

Scrolling & Overflow #

Scroll-state queries dynamically detect when content is scrollable and when sticky headers become stuck. Custom scrollbar styling and smooth scrolling enhance the browsing experience within long option lists.

• Container scroll-state queries
  container-type: scroll-state enables @container scroll-state(stuck) detection
• Sticky legends
  Group headers stick to top when scrolling, with color change when stuck
• Custom scrollbar styling
  scrollbar-width: thin and scrollbar-color with fade on hover-out
• Scroll containment
  overscroll-behavior-block: contain prevents scroll chaining
• Smooth scroll
  scroll-behavior: smooth for programmatic scrolling (motion-safe)
• Dynamic scrollable detection
  JS adds .scrollable class when content exceeds max height, CSS adjusts padding accordingly

Customizable Select Features #

New pseudo-elements provide surgical styling control over picker components, while superellipse corners deliver the modern aesthetic popularized by iOS. State selectors enable precise targeting of open and selected states.

• ::picker(select)
  Pseudo-element for styling the dropdown picker container
• ::picker-icon
  Pseudo-element for the dropdown chevron indicator
• ::checkmark
  Pseudo-element for the selected option indicator
• <selectedcontent>
  Native element that mirrors selected option content in the button
• Squircle corners
  corner-shape: superellipse(1.25) for modern rounded rectangles (with fallback)
• :open pseudo-class
  State selector for when picker is visible
• :checked on options
  State selector for selected option

Accessibility & UX #

Accessibility is built-in with proper focus indicators, keyboard navigation, and semantic markup thanks to the web platform. Touch-friendly targets and overflow handling ensure the component works elegantly across all input methods.

• Focus ring styling
  Distinct :focus (subtle) and :focus-visible (prominent)
• Disabled option support
  option[disabled] styling and hover prevention
• Text overflow handling
  text-overflow: ellipsis in button display
• Minimum touch target
  36px item height matches mobile guidelines
• Hidden option support
  JS skips [hidden] options in offset calculations
• RTL example included
  Arabic language demo validates bidirectional layout

Performance Optimizations #

Careful optimization strategies keep animations smooth while minimizing layout thrash. Smart caching and compositor hints ensure the component performs well even on lower-end devices.

• will-change: scale
  Hints to browser for compositor optimization (also fixes text shift bug)
• WeakMap offset cache
  Avoids expensive DOM measurements on every interaction;
  auto-garbage-collected
• Hardcoded layout constants
  Avoids getComputedStyle forced reflows during initialization. Tried dynamically computing these in a hidden instance, but couldn't get it as close as just "hardcoding / speficying them ahead of time" in a config
• Background clip
  background-clip: padding-box prevents background bleeding under border
• Parallel icon variants
  Pre-defined black/white SVGs avoid runtime color manipulation

Example Variations #

The component architecture supports diverse use cases, from simple toggles to rich content pickers. Each variation demonstrates how the base patterns adapt to different content and interaction models.

• Toggle with status indicators
  Colored dots (green/red/gray) for on/off/disabled states
• Avatar select
  Circular images with person names
• Multi-line options
  Title + description layout for status picker
• Grouped options
  Fieldsets with sticky legend headers
• Label above value
  Color space picker with small label text above the selected value
• Flag emoji select
  Country picker organized by region

Try It #

Experience the component in action on CodePen:

Wrapping Up #

There's room for improvement, please fork and offer feedback!

I tried many variants of animation, trying to reduce some of the shift of the positioning, but never found something that worked across all the variants. Help me?! 🙏

This select component intends to showcase what's possible when we combine modern CSS features with thoughtful progressive enhancement. The appearance: base-select property provides the foundation, while anchor positioning, scroll-state queries, and entrance animations create a polished, accessible experience.

The real power lies in how these features compose together—each enhancement builds on platform primitives rather than fighting against them. The result is a component that's maintainable, accessible, and ready for the next generation of web interfaces.

Most importantly, this approach lets us create custom experiences without sacrificing the keyboard navigation, focus management, and screen reader support that come free with native elements.

For more, checkout nice details!