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#css-animation#button#loader#transition#scroll#dashboard#ui#design-trends

Button Group CSS: 9 Adjoined Patterns

· Godrich · 9 items · 33 min read

ButtonsSCSSVanilla JSClickHoverNavigation

Button Group CSS: One of nine slides its indicator along measured coordinates, one folds overflow buttons into a more-value as the group narrows, and one

Shared-border merge — the inner border value between two adjoined buttons overlaps into one line so it never renders doubled01 btn-group-shared-border-merge Active-indicator slide — when the active-button value changes, the highlight background's position value glides to the new button along measured coordinates02 btn-group-active-slide-indicator Divider fade — the opacity value of the line between buttons fades as the pointer nears an adjacent button03 btn-group-divider-fade-on-hover Exclusive pressed state — when one button's pressed value turns on, every other button's pressed value turns off at the same instant04 btn-group-radio-exclusive-press Overflow-collapse more — when the group-width value narrows, the overflowing buttons fold into a single more-value05 btn-group-overflow-collapse-more Horizontal-vertical orient morph — when the group's orientation value flips, each button's position value travels between measured coordinates to re-lay the row06 btn-group-vertical-horizontal-orient-morph Icon-label combo reveal — as the container-width value widens, an icon button's text-label width value grows from zero into view07 btn-group-icon-label-combo-reveal Keyboard arrow focus slide — as the arrow keys move the focus value, the focus outline's position value travels along the buttons' measured coordinates08 btn-group-keyboard-arrow-focus-slide Disabled ripple block — pressing a button whose disabled value is on stops the ripple-spread value midway and answers with a shake value instead09 btn-group-disabled-ripple-block

Auto-plays · click a tile to jump to its section · all nine in one zip

None of the nine calls out to a server, writes to localStorage, or reaches for Math.random; every one of these css btn group patterns instead runs its own short list of named constants through requestAnimationFrame and changes exactly one state value — which button is active, pressed, or focused — without touching the others' markup. Because the scope of each pattern stays this narrow, naming which value actually travels between buttons is usually enough to tell which of these nine plain button group html css patterns fits a given toolbar before any of the code below gets opened.

Anatomy of nine patterns — which value changes and when

All nine call requestAnimationFrame at least once, and all nine recompute a real value inside that call rather than leaving the motion entirely to a CSS transition: item 01's tickRipples() clips a click ripple's radius to the shared seam's own measured bound, item 02's loop() integrates a STIFF/DAMP spring toward the active button's own x and w, item 03's loop() runs a pointer-distance value through smoothstep and a SMOOTH lerp per divider, item 04's render() eases each button's depth through a STIFF/DAMP spring into a brief overshoot, item 05's ResizeObserver reruns a partial-sum cutoff against an OVERFLOW_BUFFER of 24px whenever a pointer-drag or the autoplay loop changes the group's own width, item 06's flip() reads every button's getBoundingClientRect() before and after an orientation change and transitions only the leftover distance, item 07's animate() eases a label's own clip-path reveal with easeOutCubic, item 08's select() eases a focus ring's position toward the newly focused button's own rectangle, and item 09's step() runs a capped ripple spread alongside a separate damped sine-decay shake. Every listener answers a real interaction rather than a fabricated timer: 01 and 02 each pair a click with a resize listener that re-measures its own seam or indicator position, 03 tracks pointermove and clears on pointerleave rather than any click at all, 04 and 08 both pair click with keydown for ArrowLeft/ArrowRight, 05 answers a plain click on its more-button alongside pointerdown/pointermove/pointerup on a drag handle that resizes the group by hand rather than through a window resize, 06 answers only a click on its own orientation toggle, 07 answers pointerenter/pointerleave/focus/blur instead of any click or resize, and 09 answers pointerdown rather than a click. Autoplay exists on every one of the nine through that same shared .is-demo class until a visitor's first real interaction turns it off, and Math.random appears in none of the nine. Under prefers-reduced-motion: reduce, the nine split into four different shortcuts rather than one shared rule: item 01 keeps its calculation but scales RIPPLE_MS down to 1, item 02 snaps the spring's target straight onto the button without integrating toward it, items 04, 07, 08, and 09 each skip their own step function outright and jump their depth, clip-path, focus-ring position, or shake straight to the resting value, item 03's own lerp coefficient collapses to 1 so the divider snaps every frame instead of easing, item 05 assigns the group's final width directly with no per-frame loop at all, and item 06 returns out of flip() right after recording both FLIP rectangles but before ever turning them into a transform, so native layout alone repositions the row with no transform at all. Reaching for a button group html css search usually turns up exactly these nine axes — shared border, active slide, divider fade, exclusive press, overflow fold, orientation morph, label reveal, focus slide, and disabled shake — rather than a tenth hidden one.

Code per pattern

01Shared-border merge — the inner border value between two adjoined buttons overlaps into one line so it never renders doubled

The inner border value between two adjoined buttons is deliberately overlapped by BLEED_PX (6px) so it never doubles no matter which button is active. A toolbar's alignment button set or a filter-option button set suits this pattern, since each click ripple is clipped with clip-path to the shared seam's own measured left/right bound, keeping the highlight from ever crossing into the next button.

Shared-border merge — the inner border value between two adjoined buttons overlaps into one line so it never renders doubled
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01 · Shared-border merge — the inner border value between two adjoined buttons overlaps into one line so it never renders doubled — Measured area 2.754% · moving frames 11/23Original by GODRICH · SCSS and React ship in the zip · See the password

margin-left: -1.5px seamclip-path bleedBLEED_PX 6
  function easeOutQuad(t) { return 1 - (1 - t) * (1 - t); }

  function tickRipples(ts) {
    for (var i = ripples.length - 1; i >= 0; i--) {
      var r = ripples[i];
      var t = Math.min(1, (ts - r.start) / RIPPLE_MS);
      var radius = r.from + (r.to - r.from) * easeOutQuad(t);
      var left = Math.max(r.minClip, r.originX - radius);
      var right = Math.min(r.maxClip, r.originX + radius);
      r.el.style.width = radius * 2 + 'px';
      r.el.style.height = radius * 2 + 'px';
      r.el.style.marginLeft = -radius + 'px';
      r.el.style.marginTop = -radius + 'px';
      r.el.style.opacity = String(1 - t);
      // clip-path cuts the ripple so it can never spill past the measured boundary
      r.el.style.clipPath = 'inset(-9999px ' + Math.max(0, r.originX + radius - right) + 'px -9999px ' + Math.max(0, left - (r.originX - radius)) + 'px)';
      if (t >= 1) { r.el.remove(); ripples.splice(i, 1); }
    }
  }

What the numbers say

Item 01 fills 2.75% of the frame cumulatively at a 47.5 average intensity while moving in 11 of 23 sampled frames, because a clipped ripple only ever paints inside its own seam's measured width instead of the whole button row.

02Active-indicator slide — when the active-button value changes, the highlight background's position value glides to the new button along measured coordinates

When the active-button value moves to another button, the highlight's position value glides between the two buttons' measured coordinates instead of jumping there. A tab-style button group or a sort-order selector suits this pattern, since a STIFF/DAMP spring keeps integrating x and w every frame — even past the target — so the indicator's width breathes as it travels between a narrow and a wide button.

Active-indicator slide — when the active-button value changes, the highlight background's position value glides to the new button along measured coordinates
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02 · Active-indicator slide — when the active-button value changes, the highlight background's position value glides to the new button along measured coordinates — Measured area 4.878% · moving frames 13/23Original by GODRICH · SCSS and React ship in the zip · See the password

STIFF 210 / DAMP 18translateX + scaleXspring integrate
  function loop(ts) {
    if (!last) last = ts;
    var dt = Math.min(0.032, (ts - last) / 1000);
    last = ts;

    if (!cycleStart) cycleStart = ts;
    if (isDemo && !reduce) {
      var idx = Math.floor((ts - cycleStart) / CYCLE_MS) % btns.length;
      if (idx !== lastIdx) { lastIdx = idx; goTo(idx, ts); }
    }

    var ax = STIFF * (targetX - x) - DAMP * vx;
    var aw = STIFF * (targetW - w) - DAMP * vw;
    vx += ax * dt; x += vx * dt;
    vw += aw * dt; w += vw * dt;
    render();

    requestAnimationFrame(loop);
  }

What the numbers say

Item 02 fills 4.88% of the frame cumulatively at a 102.6 average intensity while moving in 13 of 23 sampled frames, because the spring keeps recomputing velocity for a few frames after the indicator visually arrives, before it fully settles.

03Divider fade — the opacity value of the line between buttons fades as the pointer nears an adjacent button

As the pointer-distance value nears a divider between two buttons, that divider's opacity value drops, softening the seam with its neighbor. A settings panel's view-toggle button set suits this pattern, since targetOpacity() runs the pointer distance through a smoothstep falloff and a SMOOTH lerp fades each divider independently rather than the whole row at once.

Divider fade — the opacity value of the line between buttons fades as the pointer nears an adjacent button
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03 · Divider fade — the opacity value of the line between buttons fades as the pointer nears an adjacent button — Measured area 0.297% · moving frames 13/23Original by GODRICH · SCSS and React ship in the zip · See the password

FALLOFF_PX 46smoothsteplerp SMOOTH .22
  function loop(ts) {
    if (!demoStart) demoStart = ts;
    var rect = root.getBoundingClientRect();
    var px = isDemo && !reduce ? demoPointerX(ts, rect.width) : pointerX;
    var centers = seamCenters();

    for (var i = 0; i < seams.length; i++) {
      var target = px == null ? 1 : targetOpacity(Math.abs(px - centers[i]));
      opac[i] += (target - opac[i]) * (reduce ? 1 : SMOOTH);
      seams[i].style.opacity = opac[i].toFixed(3);
    }

    requestAnimationFrame(loop);
  }
  requestAnimationFrame(loop);

What the numbers say

Item 03 fills 0.30% of the frame cumulatively at the lowest 24.9 average intensity while moving in 13 of 23 sampled frames, because only a handful of 1px divider lines ever repaint, never the buttons themselves.

04Exclusive pressed state — when one button's pressed value turns on, every other button's pressed value turns off at the same instant

The moment one button's pressed value turns on, every other button's pressed value turns off at the same instant, so only a single value ever stays on. A view-mode selector or a single-choice filter button set suits this pattern, since a STIFF/DAMP spring drives each button's depth past 1 before settling, lifting the shadow blur and offset into a brief overshoot on press.

Exclusive pressed state — when one button's pressed value turns on, every other button's pressed value turns off at the same instant
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04 · Exclusive pressed state — when one button's pressed value turns on, every other button's pressed value turns off at the same instant — Measured area 9.53% · moving frames 15/23Original by GODRICH · SCSS and React ship in the zip · See the password

STIFF 320 / DAMP 14translateY depthspring overshoot
  btns.forEach(function (b, i) {
    b.addEventListener('click', function () { human(); setChecked(i); b.focus({ preventScroll: true }); });
  });

  root.addEventListener('keydown', function (e) {
    if (e.key !== 'ArrowRight' && e.key !== 'ArrowLeft') return;
    human();
    var dir = e.key === 'ArrowRight' ? 1 : -1;
    var next = (checkedIdx + dir + btns.length) % btns.length;
    setChecked(next);
    btns[next].focus({ preventScroll: true });
    e.preventDefault();
  });

  function render(i) {
    var d = depth[i];
    var overshootLift = Math.max(0, -(d - 1)) * -2; // in the overshoot range (d>1), express a slightly deeper press
    var y = d * 3 + (d > 1 ? (d - 1) * 4 : 0);
    var blur = 14 - d * 8;
    var offY = 8 - d * 6;
    btns[i].style.transform = 'translateY(' + y.toFixed(2) + 'px)';
    btns[i].style.boxShadow = '0 ' + Math.max(1, offY).toFixed(1) + 'px ' + Math.max(4, blur).toFixed(1) + 'px rgba(23,20,26,.34)';
    btns[i].classList.toggle('rep__btn--on', d > 0.5);
  }

What the numbers say

Item 04 fills 9.53% of the frame cumulatively at a 77.3 average intensity while moving in 15 of 23 sampled frames, because the overshoot recalculates a blurred box-shadow for every button on every frame, not only the one just pressed.

05Overflow-collapse more — when the group-width value narrows, the overflowing buttons fold into a single more-value

Once the group-width value falls below the buttons' combined width value, the overflowing ones fold into a single more-value. A toolbar button set on a narrow screen suits this pattern, since a partial-sum loop adds each button's cached width plus an OVERFLOW_BUFFER of 24px until the next one would no longer fit, then hides everything past that cutoff.

Overflow-collapse more — when the group-width value narrows, the overflowing buttons fold into a single more-value
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05 · Overflow-collapse more — when the group-width value narrows, the overflowing buttons fold into a single more-value — Measured area 6.63% · moving frames 22/23Original by GODRICH · SCSS and React ship in the zip · See the password

OVERFLOW_BUFFER 24getBoundingClientRect cachewidths cutoff sum
    var sumAll = widths.reduce(function (s, w) { return s + w; }, 0) + gap * (widths.length - 1);
    var cutoff = widths.length;
    if (sumAll > avail) {
      var sum = 0;
      cutoff = 0;
      for (var i = 0; i < widths.length; i++) {
        var add = widths[i] + (i > 0 ? gap : 0);
        if (sum + add + moreWidth > avail) break;
        sum += add;
        cutoff = i + 1;
      }
      cutoff = Math.max(1, cutoff);
    }

    btns.forEach(function (b, i) { b.hidden = i >= cutoff; });
    var overflowCount = widths.length - cutoff;
    more.hidden = overflowCount === 0;
    more.textContent = 'More ▾ (' + overflowCount + ')';

What the numbers say

Item 05 fills 6.63% of the frame cumulatively at a 121.3 average intensity while moving in 22 of 23 sampled frames, because the resize-driven cutoff sum reruns on nearly every sampled frame instead of only once per breakpoint.

06Horizontal-vertical orient morph — when the group's orientation value flips, each button's position value travels between measured coordinates to re-lay the row

When the group's orientation value flips, each button's position value travels between measured coordinates as the row re-forms. A responsive toolbar or a button set that folds into a sidebar suits this pattern, since flip() reads every button's getBoundingClientRect() before and after the layout change, then transitions only the leftover difference over FLIP_MS (480ms).

Horizontal-vertical orient morph — when the group's orientation value flips, each button's position value travels between measured coordinates to re-lay the row
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06 · Horizontal-vertical orient morph — when the group's orientation value flips, each button's position value travels between measured coordinates to re-lay the row — Measured area 15.29% · moving frames 16/23Original by GODRICH · SCSS and React ship in the zip · See the password

FLIP_MS 480FLIP Invert Playforced reflow
  function flip(apply) {
    var first = btns.map(function (b) { return b.getBoundingClientRect(); });
    apply();
    var last = btns.map(function (b) { return b.getBoundingClientRect(); });

    if (reduce) return; // keep the calculation but apply it immediately, skipping the animation

    btns.forEach(function (b, i) {
      var dx = first[i].left - last[i].left;
      var dy = first[i].top - last[i].top;
      if (!dx && !dy) return;
      b.style.transition = 'none';
      b.style.transform = 'translate(' + dx + 'px,' + dy + 'px)';
      // only after a forced reflow paints the initial transform does the return transition actually play
      b.getBoundingClientRect();
      requestAnimationFrame(function () {
        b.style.transition = 'transform ' + FLIP_MS + 'ms cubic-bezier(.22,.9,.32,1)';
        b.style.transform = 'translate(0,0)';
      });
    });
  }

What the numbers say

Item 06 fills the highest 15.29% of the frame cumulatively at a 120.7 average intensity while moving in 16 of 23 sampled frames, because every button in the group travels its own distance at once instead of one button moving alone.

07Icon-label combo reveal — as the container-width value widens, an icon button's text-label width value grows from zero into view

Once the container-width value crosses a threshold, an icon button's label-width value grows from zero to its full text width. A responsive action button set or a button group inside a card suits this pattern, since hovering or focusing a button drives animate() through an easeOutCubic clip-path reveal over 400ms, measured against that label's own real text width rather than a fixed guess.

Icon-label combo reveal — as the container-width value widens, an icon button's text-label width value grows from zero into view
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07 · Icon-label combo reveal — as the container-width value widens, an icon button's text-label width value grows from zero into view — Measured area 0.602% · moving frames 9/23Original by GODRICH · SCSS and React ship in the zip · See the password

dur 400 easeOutCubicclip-path revealmeasured text width
  function render(cell) {
    var pct = (1 - cell.progress) * 100;
    cell.reveal.style.clipPath = 'inset(0 ' + pct.toFixed(2) + '% 0 0)';
    cell.label.style.opacity = String(cell.progress);
  }

  function animate(cell, to) {
    cell.target = to;
    var from = cell.progress;
    if (reduce) { cell.progress = to; render(cell); return; }
    if (cell.raf) cancelAnimationFrame(cell.raf);
    var dur = 400, t0 = 0;
    function step(ts) {
      if (!t0) t0 = ts;
      var t = Math.min(1, (ts - t0) / dur);
      cell.progress = from + (to - from) * easeOutCubic(t);
      render(cell);
      if (t < 1) cell.raf = requestAnimationFrame(step);
      else cell.raf = 0;
    }
    cell.raf = requestAnimationFrame(step);
  }

What the numbers say

Item 07 fills 0.60% of the frame cumulatively at a 76.4 average intensity while moving in the fewest 9 of 23 sampled frames, because the reveal only plays for the short window right after a pointer or focus event, not continuously.

08Keyboard arrow focus slide — as the arrow keys move the focus value, the focus outline's position value travels along the buttons' measured coordinates

Each arrow-key press moves the focus value to the next button, and the focus outline's position value travels along the buttons' measured coordinates. An accessible toolbar or a keyboard-driven option button set suits this pattern, since select() updates aria-checked and tabIndex on every button while a FOCUS_EASE easing carries the ring's own left offset and width toward the newly focused button's own rectangle.

Keyboard arrow focus slide — as the arrow keys move the focus value, the focus outline's position value travels along the buttons' measured coordinates
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08 · Keyboard arrow focus slide — as the arrow keys move the focus value, the focus outline's position value travels along the buttons' measured coordinates — Measured area 8.261% · moving frames 18/23Original by GODRICH · SCSS and React ship in the zip · See the password

FOCUS_EASE easeInOuttranslate + resize ringmeasured coord tween
  function select(i, focus) {
    btns.forEach(function (b, j) {
      b.setAttribute('aria-checked', String(j === i));
      b.tabIndex = j === i ? 0 : -1;
    });
    current = i;
    moveRing(i);
    if (focus) btns[i].focus({ preventScroll: true });
  }

  btns.forEach(function (b, i) {
    b.addEventListener('click', function () { human(); select(i, false); });
    b.addEventListener('keydown', function (e) {
      if (e.key !== 'ArrowRight' && e.key !== 'ArrowLeft') return;
      human();
      e.preventDefault();
      var dir = e.key === 'ArrowRight' ? 1 : -1;
      select((current + dir + btns.length) % btns.length, true);
    });
  });

What the numbers say

Item 08 is the one item worth calling highest intensity here, filling 8.26% of the frame cumulatively at a 190.7 average intensity while moving in 18 of 23 sampled frames, because the ring itself is a bright accent outline, so every pixel it crosses reads as a large change.

09Disabled ripple block — pressing a button whose disabled value is on stops the ripple-spread value midway and answers with a shake value instead

Pressing a button whose disabled value is on still starts the ripple-spread value, but it halts halfway and the button's shake value answers briefly instead. A permission-locked action button or a submit button locked after completion suits this pattern, since the ripple's spread is capped at haltR while a separate damped SHAKE_FREQ/SHAKE_DECAY oscillator drives the button's own horizontal sine-decay shake.

Disabled ripple block — pressing a button whose disabled value is on stops the ripple-spread value midway and answers with a shake value instead
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09 · Disabled ripple block — pressing a button whose disabled value is on stops the ripple-spread value midway and answers with a shake value instead — Measured area 2.133% · moving frames 16/23Original by GODRICH · SCSS and React ship in the zip · See the password

SHAKE_FREQ 26 / DECAY 6.5sin decay oscillatorHALT_RATIO .5 ripple
    function step(ts) {
      if (!t0) t0 = ts;
      var t = (ts - t0) / 1000;
      var tt = Math.min(1, (ts - t0) / dur);

      // ripple: decelerating spread from 0 to haltR, then stop (it never grows past that) — fade runs independently of the spread
      var spread = haltR * (1 - Math.pow(1 - Math.min(1, tt * 1.6), 2));
      cell.ripple.style.transform = 'translate(-50%,-50%) scale(' + Math.max(0.001, spread / 4) + ')';
      cell.ripple.style.opacity = String(Math.max(0, 1 - tt));

      // shake: a damped oscillator — computed every frame, not a canvas keyframe
      var shakeT = Math.min(t, SHAKE_MS / 1000);
      var dx = SHAKE_AMPLITUDE * Math.sin(SHAKE_FREQ * shakeT) * Math.exp(-SHAKE_DECAY * shakeT);
      cell.btn.style.transform = 'translate(' + dx.toFixed(2) + 'px,0)';

      if (tt < 1) cell.raf = requestAnimationFrame(step);
      else { cell.raf = 0; cell.btn.style.transform = 'translate(0,0)'; }
    }
    cell.raf = requestAnimationFrame(step);

What the numbers say

Item 09 fills 2.13% of the frame cumulatively at a 45.7 average intensity while moving in 16 of 23 sampled frames, because the shake amplitude itself stays small even while the oscillator keeps computing on every one of those frames.

Where values change position and size — active, width, and focus basis

A button group tailwind css utility layer usually means a single class swap, but three of these nine push further than that. Item 02's highlight background ties its own position directly to which button is active: x and w are both spring targets, so the indicator's width itself breathes wider or narrower depending on which button it is currently gliding toward, not only where it sits. Item 05's overflow fold changes size rather than position: the group-width value decides a cutoff index through a partial-sum loop, so a button is never told to shrink — it is only told whether it still fits before the next one would overflow the group. Item 08's focus ring, by contrast, changes position without touching size at all: FOCUS_EASE carries the ring's own left offset toward whichever button holds focus, while its width only updates to match that button's own measured rectangle. Swapping these constants into a different utility layer changes nothing about which value moves — item 02's spring still targets x and w, item 05's cutoff still sums cached widths — only the class names around them differ.

That active-versus-width-versus-focus split matters most once a pattern like this leaves this page for a real toolbar. 9 CSS Button Animations (SCSS + React, copy-paste) drives a single button's own hover or press value in isolation, while every pattern above instead coordinates one button's state against its siblings in the same group. 9 css button design ideas — candy, push, loading changes a button's own surface treatment — a gradient, a press depth, a loading fill — rather than a value that travels between adjoined buttons. 9 Icon Button CSS Patterns — Press, Drag, Expand expands or drags a single icon button's own size and position, never a value shared across a row of siblings the way the active indicator or the focus ring is here. Open the zip once with he9ea98k and every one of these nine button group patterns unlocks together, so there's no need to reopen it per item.

Where it breaks — rapid clicking, narrow screens, keyboard focus

Nine patterns that each compute their own timing also fail in three different ways once real users stop clicking one button at a time.

Rapid clicks before a spring settles

Item 04's render() reads depth[i] fresh on every click, so clicking a different button before the spring settles just retargets the same overshoot instead of snapping back to zero first. Item 02 behaves the same way — its loop() keeps integrating x and w toward whatever the latest targetX/targetW happen to be, so a fast second click simply redirects a spring that is already moving rather than restarting it.

Narrow screens and the overflow buffer

Item 05's cutoff loop only ever hides a whole button, never part of one, so a screen narrower than even the first button's own width plus OVERFLOW_BUFFER still leaves the more-value visible with every button folded behind it. Item 06's flip() measures rectangles right before an orientation change, so clicking its toggle again before the transition finishes can hand it a stale first rectangle from a layout that is already mid-flight.

Keyboard focus when a button hides

Item 08's select() moves tabIndex and the focus ring together, so its own roving-tabindex pattern keeps working even if a sibling button were hidden. Item 05 does not coordinate with that pattern at all — folding a focused button into the more-value would drop focus onto whatever hidden leaves behind, since collapsing buttons and moving focus are two systems that never call each other here.

Three variants and accessibility

Lowering item 02's DAMP from 18 to 9 leaves an overshoot in the spring, so the indicator slightly overshoots its target button and springs back, making the slide feel bouncier. Cutting item 05's OVERFLOW_BUFFER from 24 to 8px keeps buttons expanded longer, pushing the collapse point much closer to the screen edge. Switching item 08's FOCUS_EASE from easeInOut to linear removes the slow-in and slow-out, so the ring travels to the next button at one constant speed and arrow-key moves feel mechanical and clipped.

Variant What changes What it doesn't touch
Slide-indicator travel time DAMP 18 → 9 The STIFF value, the spring formula, which button is active
Overflow-collapse buffer OVERFLOW_BUFFER 24 → 8 The cutoff loop itself, the more-value's own label, the group-width measurement
Focus-ring travel speed FOCUS_EASE easeInOut → linear The radiogroup role, aria-checked, the ArrowLeft/ArrowRight handler

Only items 04 and 08 set role="radiogroup" with aria-checked on each button, a roving tabIndex, and focus({preventScroll:true}) on every arrow-key move, since those two are the only patterns that enforce a single true selection the way native radio buttons do. The other seven stay plain role="group" buttons instead: 01, 02, and 06 mirror their own state through aria-pressed since more than one of those can matter, 05 adds aria-expanded on its own more-button and role="toolbar" on the track, and 03, 07, and 09 expose no pressed state at all because hovering, revealing, or shaking never changes which value is actually selected. Reduced motion collapses into three shortcuts: item 01 keeps its ripple math but scales the duration to 1, items 02, 04, 07, 08, and 09 skip their own step function and jump straight to the resting value, and items 03, 05, and 06 fall back on a plain scss transition: none, since their own JS already snaps the value directly rather than depending on a per-frame loop to finish.

FAQ

Is this button group css design set nine separate scripts, or one shared component with a config

Nine separate scripts — each one lives in its own file with its own set of named constants, and the code fence sitting next to a demo is exactly what that demo runs, with no shared template swapping variables in behind the scenes.

Does item 01's shared border come from a real CSS border, or is it faked with clip-path

Both play a part: the seam itself is a real 1px background line placed with a negative margin-left, while clip-path only clips the click ripple so it can never visually spill past that seam's own measured edge.

Why do only items 04 and 08 use a radiogroup instead of plain buttons

Because those two are the only patterns where exactly one button must stay selected at all times — a native role="radiogroup" with aria-checked and a roving tabIndex tells assistive tech that, while the rest allow more than one pressed state or expose no selection state at all.

Sources: MDN — ARIA toolbar role · MDN — ARIA group role · MDN — :focus-visible · MDN — Element.getBoundingClientRect()

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