∞ forever components

Drag & Reorder

Split Pane

Two color-coded panes (amber/pink) split by a draggable cyan divider; the divider springs to position with grip squash, auto-sweeping gently when idle.

cssmedium complexitysubtle motionpointer

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When to use it

Code editors, comparison views, side-by-side content layouts, or any UI demo needing a resizable split panel.

When not to

Contexts where the auto-sweep demo loop is distracting — remove the phase loop and set demo=false for production use.

Working with an AI agent

Every component ships agent-ready metadata. An example instruction for this one:

Change accent color from cyan (#22d3ee) to purple (#a855f7) by updating --ac in :root, and slow the demo sweep by changing phase+=0.012 to phase+=0.006. Theme: dark tokens live in :root, the light variant in :root[data-theme="light"]; ?theme=light or a {type:'forever:theme'} postMessage switches at runtime.

Safe to edit

  • accent color (--ac CSS variable)
  • spring constants (K=0.16, D=0.78)
  • demo sweep speed (phase+=0.012)
  • min/max split limits (MIN=14, MAX=86)
  • pane colors (--l and --r CSS variables)
  • theme tokens (:root dark defaults + [data-theme=light] overrides)

Keep intact

  • IIFE wrapper
  • prefers-reduced-motion guard with static fallback
  • visibilitychange pause/resume
  • pointer capture on bar for smooth drag
  • theme hook (?theme= bootstrap + forever:theme message listener + theme tokens)

Known limitations

  • Auto-cycles by default — set demo=false and remove the phase block for production
  • pane widths hardcoded at 50% with scaleX trick; content inside panes clips at edges

split-panedividerdragspringresizeui-controllayout

More Drag & Reorder components

  • FLIP Reorder7-row list reorders via FLIP spring physics on drag or arrow-key input; lifted card gains glow outline while others spring to new slots. Auto-demos when idle.
  • Kanban MoveThree-column kanban board where a cyan card lifts and spring-animates between lanes via FLIP. Auto-demos on a timer; supports arrow keys and horizontal drag.
  • Pull to RefreshA 5-row canvas list springs down on drag, revealing diagonal bars and a rotating geometric indicator; releasing past threshold triggers a 1.5s sync spinner.
  • Sortable Grid3x3 grid of colored numbered tiles that spring-animate into position as tiles are dragged or swapped; auto-shuffles on idle as a demo.
  • Snap SliderOchre-accent range slider with 9 tick detents; thumb flicks with spring momentum and rubber-bands at ends. Self-demos on idle, accepts keyboard input.
  • Dual RangeCanvas dual-range slider with two spring-driven thumbs (white lo, amber hi), hatched fill, delta readout, and tick marks. Auto-breathes when idle.