diff --git a/frontend/packages/swarm-ui/src/lib/motion-apply.ts b/frontend/packages/swarm-ui/src/lib/motion-apply.ts
index 49717c7f..42c19f7e 100644
--- a/frontend/packages/swarm-ui/src/lib/motion-apply.ts
+++ b/frontend/packages/swarm-ui/src/lib/motion-apply.ts
@@ -3,14 +3,15 @@
 // when the override is "system" (letting `prefers-reduced-motion`
 // alone decide, same as today).
 //
-// Built ahead of swarm-ui having any CSS animation to gate — the
-// settings surface itself was scoped to cover theme *and* motion
-// together (both named in the same go-ahead), and the marginal cost of
-// the storage/attribute plumbing was near zero riding alongside the
-// theme override's real wiring. `Shell`'s page-switch animation (the
-// nav indicator's slide + the page-body pop) is the first real
-// consumer — see `shell/Shell.css`'s file-top comment for the
-// three-rule gate shape every animation here follows:
+// Currently inert: swarm-ui has zero CSS animations as of this file's
+// writing (the design guide's "playful whimsy" motion — the matrix-rain
+// home background — lives in the dashboard package, not swarm-ui). This
+// hook exists because the settings surface itself was scoped to cover
+// theme *and* motion together (both named in the same go-ahead), and the
+// marginal cost of the storage/attribute plumbing is near zero riding
+// alongside the theme override's real wiring — but there is genuinely
+// nothing in swarm-ui for `data-motion` to gate yet. The first swarm-ui
+// animation's own CSS is what makes this do anything, e.g.:
 //   @media (prefers-reduced-motion: reduce) { ... }
 //   :root[data-motion='reduce'] { ... same rule ... }
 //   :root[data-motion='allow'] { /* opt back in despite OS-level reduce */ }
diff --git a/frontend/packages/swarm-ui/src/shell/Shell.css b/frontend/packages/swarm-ui/src/shell/Shell.css
index 77e59c13..615e40f7 100644
--- a/frontend/packages/swarm-ui/src/shell/Shell.css
+++ b/frontend/packages/swarm-ui/src/shell/Shell.css
@@ -8,17 +8,7 @@
    menu: a narrow viewport (phone or a tiled desktop window) wraps onto
    a second line instead of overflowing — "don't break, don't
    over-invest" is the explicit scope here, not full mobile navigation
-   redesign.
-
-   Page-switch animation (see Shell.tsx's file-top comment for the JS
-   half): both the nav indicator's slide and the page-body pop follow
-   the same three-rule motion-guard shape `lib/motion-apply.ts`'s own
-   doc comment specifies — a base rule,
-   `@media (prefers-reduced-motion: reduce)` to respect the OS default,
-   `:root[data-motion='reduce']` as the explicit override (same
-   specificity as the media rule, so source order after it wins), then
-   `:root[data-motion='allow']` last to re-enable despite an OS-level
-   reduce preference. */
+   redesign. */
 .shell-header {
   display: flex;
   align-items: center;
@@ -30,34 +20,13 @@
 }
 .shell-brand {
   font-weight: 600;
-  /* Base colour only — Shell.tsx overrides it inline to the same
-     currently-active-tab accent `.shell-nav-indicator` uses (falling
-     back to this `--purple` before the first measurement lands, which
-     is also the "hives" default route's own accent, so there's no
-     visible mismatch at first paint). Transition lives here, same
-     140ms hop cadence + the same three-rule motion guard as the
-     indicator, so this and the indicator read as one thing changing,
-     not two independently-synced ones. */
   color: var(--purple);
   letter-spacing: 0.02em;
-  transition: color 140ms ease;
-}
-@media (prefers-reduced-motion: reduce) {
-  .shell-brand {
-    transition: none;
-  }
-}
-:root[data-motion='reduce'] .shell-brand {
-  transition: none;
-}
-:root[data-motion='allow'] .shell-brand {
-  transition: color 140ms ease;
 }
 .shell-nav {
   display: flex;
   flex-wrap: wrap;
   gap: 1em;
-  position: relative; /* anchor for .shell-nav-indicator */
 }
 /* Holds `SettingsMenu` + `LinksMenu` — one `margin-left: auto` on the
    wrapper, not one on each child (see Shell.tsx's comment for why two
@@ -91,79 +60,15 @@
   color: var(--fg);
 }
 .shell-nav-link-text {
-  padding-bottom: 0.25em; /* gap between the text and .shell-nav-indicator below it */
+  padding-bottom: 0.25em;
+  border-bottom: 2px solid transparent;
 }
 .shell-nav-link-active {
   color: var(--fg);
-}
-/* Shared underline, one element instead of one border-bottom per link
-   — see Shell.tsx's file-top comment. `left`/`top`/`width` are set
-   inline per-render from a real measurement; only the *transition*
-   between those values lives here. 140ms matches Shell.tsx's `HOP_MS`
-   exactly, so one hop's CSS transition finishes right as the next
-   hop's JS-driven style update lands, instead of the two blending into
-   an averaged easing curve. */
-.shell-nav-indicator {
-  position: absolute;
-  height: 2px;
-  border-radius: 1px;
-  transition:
-    left 140ms ease,
-    top 140ms ease,
-    width 140ms ease,
-    background-color 140ms ease;
-}
-@media (prefers-reduced-motion: reduce) {
-  .shell-nav-indicator {
-    transition: none;
-  }
-}
-:root[data-motion='reduce'] .shell-nav-indicator {
-  transition: none;
-}
-:root[data-motion='allow'] .shell-nav-indicator {
-  transition:
-    left 140ms ease,
-    top 140ms ease,
-    width 140ms ease,
-    background-color 140ms ease;
-}
-/* Suppresses the transition for exactly one render — the indicator's
-   very first real position, so it snaps into place instead of visibly
-   growing from the unmounted `left:0/width:0/transparent` fallback (see
-   Shell.tsx's `indicatorSettledOnce`). Two-class selector so it wins
-   over the plain `.shell-nav-indicator` rule above without `!important`,
-   same reasoning `:root[data-motion='reduce']`'s extra attribute
-   selector already relies on. */
-.shell-nav-indicator.shell-nav-indicator-instant {
-  transition: none;
+  border-bottom-color: var(--purple);
 }
 .shell-body {
   max-width: 60em;
   margin: 0 auto;
   padding: 1.5em 1.25em;
-  /* Plain fade, deliberately — mara's call on review: a scale+overshoot
-     "pop" (this rule's first cut) read as too much for a first pass.
-     Keeping it simple leaves room to make this fancier later without
-     having shipped something to walk back first. */
-  animation: shell-page-enter 160ms ease;
-}
-@keyframes shell-page-enter {
-  from {
-    opacity: 0;
-  }
-  to {
-    opacity: 1;
-  }
-}
-@media (prefers-reduced-motion: reduce) {
-  .shell-body {
-    animation: none;
-  }
-}
-:root[data-motion='reduce'] .shell-body {
-  animation: none;
-}
-:root[data-motion='allow'] .shell-body {
-  animation: shell-page-enter 160ms ease;
 }
diff --git a/frontend/packages/swarm-ui/src/shell/Shell.tsx b/frontend/packages/swarm-ui/src/shell/Shell.tsx
index eb6ac85a..cdd5d22d 100644
--- a/frontend/packages/swarm-ui/src/shell/Shell.tsx
+++ b/frontend/packages/swarm-ui/src/shell/Shell.tsx
@@ -12,34 +12,20 @@
 // has exactly one place that needs to know its own nav, and this is
 // it. Grows additively as real routes land (a swarm-wide agent roster
 // is next); no speculative entries.
-//
-// Page-switch animation, two pieces (motion-guard rules live in
-// Shell.css): `.shell-body` remounts on every navigation
-// (`key={location}`) to replay a plain fade-in, and a single shared
-// underline (`.shell-nav-indicator`, replacing what used to be a
-// per-link border) hops through every nav item it passes over on its
-// way to the new active one, not just a straight two-point tween — a
-// nav hives→components jump visibly touches "new agent" and "jobs" in
-// between, position and colour together. Accent is a discrete cycle
-// through the existing base16 chromatic slots (`NAV_ITEMS`' `accent`
-// field), not a continuous hue rotation — everything here still
-// derives from base16, same rule the rest of the palette follows.
-// `.shell-brand` rides the identical accent value (`navAccent` below),
-// so the header reads as one accent changing, not the underline alone.
-import { useEffect, useRef, useState } from 'preact/hooks';
+import { useEffect, useState } from 'preact/hooks';
 import type { ComponentChildren } from 'preact';
-import { Link, useLocation } from 'wouter-preact';
+import { Link, useRoute } from 'wouter-preact';
 import { LinksMenu } from './LinksMenu.js';
 import { SettingsMenu } from './SettingsMenu.js';
 import { useApplyThemeOverride } from '../lib/theme-apply.js';
 import { useApplyMotionOverride } from '../lib/motion-apply.js';
 import './Shell.css';
 
-const NAV_ITEMS: { href: string; label: string; accent: string }[] = [
-  { href: '/', label: 'hives', accent: 'var(--purple)' },
-  { href: '/create-agent', label: 'new agent', accent: 'var(--cyan)' },
-  { href: '/jobs', label: 'jobs', accent: 'var(--pink)' },
-  { href: '/components', label: 'components', accent: 'var(--blue)' },
+const NAV_ITEMS: { href: string; label: string }[] = [
+  { href: '/', label: 'hives' },
+  { href: '/create-agent', label: 'new agent' },
+  { href: '/jobs', label: 'jobs' },
+  { href: '/components', label: 'components' },
 ];
 
 // Static fallback — matches `index.html`'s `<title>` default, so a page
@@ -48,80 +34,21 @@ const NAV_ITEMS: { href: string; label: string; accent: string }[] = [
 // same generic label the pre-fetch page already showed, not a blank.
 const DEFAULT_BRAND = 'hyperhive swarm';
 
-interface IndicatorRect {
-  left: number;
-  top: number;
-  width: number;
-  accent: string;
-}
-
-// One hop's travel time — also the interval between hops, so each leg
-// finishes (per `.shell-nav-indicator`'s own CSS transition duration,
-// kept equal to this) before the next one starts rather than the two
-// blending into a single averaged easing curve.
-const HOP_MS = 140;
-
-// `data-motion`/`prefers-reduced-motion` gate for the JS-driven hop
-// sequence — the CSS-only pieces (the fade, the indicator's own
-// transition) gate via the three-rule pattern in Shell.css, but a
-// multi-step `setTimeout` sequence has no CSS equivalent to hook, so it
-// checks the same two sources directly. `data-motion` takes precedence
-// over the OS preference either direction (reduce *or* allow), same
-// override semantics `lib/motion-apply.ts` establishes.
-function prefersReducedMotion(): boolean {
-  const override = document.documentElement.dataset.motion;
-  if (override === 'reduce') return true;
-  if (override === 'allow') return false;
-  return window.matchMedia('(prefers-reduced-motion: reduce)').matches;
-}
-
-function NavLink({
-  href,
-  label,
-  active,
-  textRef,
-}: {
-  href: string;
-  label: string;
-  active: boolean;
-  textRef: (el: HTMLSpanElement | null) => void;
-}) {
+function NavLink({ href, label }: { href: string; label: string }) {
+  const [active] = useRoute(href);
   return (
     <Link href={href} className="shell-nav-link">
       {/* Touch target (min-height) lives on the <a> so the whole row is
-          tappable. The underline itself no longer lives here — see
-          `.shell-nav-indicator` — this span is still what gets
-          measured to position that shared indicator, so it hugs just
-          the text rather than the full-height tappable box. */}
-      <span
-        ref={textRef}
-        class={'shell-nav-link-text' + (active ? ' shell-nav-link-active' : '')}
-      >
-        {label}
-      </span>
+          tappable; the active-state underline lives on this inner span
+          so it hugs the text instead of sitting at the bottom of the
+          full-height box, ~0.7em away from it. */}
+      <span class={'shell-nav-link-text' + (active ? ' shell-nav-link-active' : '')}>{label}</span>
     </Link>
   );
 }
 
 export function Shell({ children }: { children: ComponentChildren }) {
   const [swarmName, setSwarmName] = useState<string | null>(null);
-  const [location] = useLocation();
-  const navRef = useRef<HTMLElement | null>(null);
-  const textRefs = useRef<Record<string, HTMLSpanElement | null>>({});
-  const [indicator, setIndicator] = useState<IndicatorRect | null>(null);
-  // The nav-item index the indicator is currently sitting at (or mid-hop
-  // from) — distinct from `location`'s own index, since the two only
-  // agree once every intermediate hop has landed. `-1` = not settled
-  // anywhere yet (first mount) or on a route with no nav item (404).
-  const settledIndexRef = useRef(-1);
-  // False until the indicator's very first real position has committed —
-  // gates `.shell-nav-indicator-instant` (see Shell.css) so that first
-  // placement snaps instead of *transitioning in* from the unmounted
-  // `left:0/width:0/transparent` fallback, which read as "no underline at
-  // all" on a fresh page load (reported live by mara, reproduced here with
-  // a zoomed pixel-level screenshot check — real, not a rendering fluke).
-  // Every subsequent change (a real navigation) still animates normally.
-  const [indicatorSettledOnce, setIndicatorSettledOnce] = useState(false);
 
   // Applied once here, not inside `SettingsMenu` — every route mounts
   // through this one `<Shell>`, so the override takes effect regardless
@@ -132,90 +59,6 @@ export function Shell({ children }: { children: ComponentChildren }) {
   useApplyThemeOverride();
   useApplyMotionOverride();
 
-  // Measures nav item `index`'s rect relative to `.shell-nav`.
-  // `getBoundingClientRect()` on both elements at the same tick keeps
-  // this scroll-position-agnostic — a difference of two
-  // viewport-relative rects is scroll-invariant, no separate
-  // scroll-offset bookkeeping needed.
-  function measureIndex(index: number): IndicatorRect | null {
-    const navEl = navRef.current;
-    const item = NAV_ITEMS[index];
-    const textEl = item ? textRefs.current[item.href] : null;
-    if (!navEl || !item || !textEl) return null;
-    const navRect = navEl.getBoundingClientRect();
-    const textRect = textEl.getBoundingClientRect();
-    return {
-      left: textRect.left - navRect.left,
-      top: textRect.bottom - navRect.top,
-      width: textRect.width,
-      accent: item.accent,
-    };
-  }
-
-  // Drives the indicator through every nav item between where it was
-  // and the new active one — see the file-top comment for why (mara:
-  // "navigating from a to c animates [a's colour] -> [b's colour] ->
-  // [c's colour]"). Re-runs on navigation; a separate resize listener
-  // below re-measures the already-settled position without re-hopping
-  // (a reflow isn't a navigation).
-  useEffect(() => {
-    const targetIndex = NAV_ITEMS.findIndex((item) => item.href === location);
-    if (targetIndex === -1) {
-      settledIndexRef.current = -1;
-      setIndicator(null);
-      return;
-    }
-    const fromIndex = settledIndexRef.current;
-    // First mount, a route with no nav item just left, or reduced
-    // motion: land directly, no intermediate hops to sweep through.
-    if (fromIndex === -1 || prefersReducedMotion()) {
-      settledIndexRef.current = targetIndex;
-      setIndicator(measureIndex(targetIndex));
-      return;
-    }
-    const step = targetIndex > fromIndex ? 1 : -1;
-    let cancelled = false;
-    let timeoutId: number | undefined;
-    function hop(current: number) {
-      const next = current + step;
-      setIndicator(measureIndex(next));
-      settledIndexRef.current = next;
-      if (next !== targetIndex) {
-        timeoutId = window.setTimeout(() => {
-          if (!cancelled) hop(next);
-        }, HOP_MS);
-      }
-    }
-    hop(fromIndex);
-    return () => {
-      cancelled = true;
-      if (timeoutId !== undefined) window.clearTimeout(timeoutId);
-    };
-  }, [location]);
-
-  // Fires the render *after* the indicator's first non-null commit —
-  // deliberately one tick behind, not folded into the effect above,
-  // because the instant/animated class has to still read "instant" on
-  // the very render where `indicator` itself first goes non-null (that's
-  // the snap this exists for); only from the render after that should
-  // transitions be armed.
-  useEffect(() => {
-    if (indicator && !indicatorSettledOnce) setIndicatorSettledOnce(true);
-  }, [indicator, indicatorSettledOnce]);
-
-  // Re-measures the current (already-settled) position on resize — the
-  // nav's own `flex-wrap` means a link's position genuinely changes at
-  // narrow widths, not just its route. Not part of the hop effect above
-  // since a reflow shouldn't restart the sweep animation.
-  useEffect(() => {
-    function onResize() {
-      if (settledIndexRef.current === -1) return;
-      setIndicator(measureIndex(settledIndexRef.current));
-    }
-    window.addEventListener('resize', onResize);
-    return () => window.removeEventListener('resize', onResize);
-  }, []);
-
   // Fetched once here, not per-page: every route mounts inside one
   // `<Shell>`, and the swarm's name doesn't change within a page
   // visit. A fetch failure is silently ignored — `swarmName` just stays
@@ -238,43 +81,14 @@ export function Shell({ children }: { children: ComponentChildren }) {
     document.title = brand;
   }, [brand]);
 
-  // Same value the indicator itself is drawn with, including mid-sweep —
-  // the brand text rides the identical hop sequence rather than
-  // computing its own, so "the header's accent" reads as one thing
-  // changing, not two things that happen to agree at rest.
-  const navAccent = indicator?.accent ?? 'var(--purple)';
-
   return (
     <div class="shell">
       <header class="shell-header">
-        <span class="shell-brand" style={{ color: navAccent }}>
-          {brand}
-        </span>
-        <nav class="shell-nav" ref={navRef}>
+        <span class="shell-brand">{brand}</span>
+        <nav class="shell-nav">
           {NAV_ITEMS.map((item) => (
-            <NavLink
-              key={item.href}
-              href={item.href}
-              label={item.label}
-              active={item.href === location}
-              textRef={(el) => {
-                textRefs.current[item.href] = el;
-              }}
-            />
+            <NavLink key={item.href} href={item.href} label={item.label} />
           ))}
-          {/* Shared sliding underline — see the file-top comment. Hidden
-              (zero width) rather than unmounted when there's no active
-              nav item (404), so it doesn't pop in with a stale position
-              the next time a real nav item becomes active. */}
-          <span
-            class={'shell-nav-indicator' + (indicatorSettledOnce ? '' : ' shell-nav-indicator-instant')}
-            style={{
-              left: `${indicator?.left ?? 0}px`,
-              top: `${indicator?.top ?? 0}px`,
-              width: `${indicator?.width ?? 0}px`,
-              backgroundColor: indicator?.accent ?? 'transparent',
-            }}
-          />
         </nav>
         {/* Single `margin-left: auto` on the wrapper, not on each menu
             individually — two adjacent flex items both set to
@@ -285,11 +99,7 @@ export function Shell({ children }: { children: ComponentChildren }) {
           <LinksMenu />
         </div>
       </header>
-      {/* Keyed by route so it remounts (and replays its entrance
-          animation) on every navigation — see the file-top comment. */}
-      <div class="shell-body" key={location}>
-        {children}
-      </div>
+      <div class="shell-body">{children}</div>
     </div>
   );
 }