diff --git a/index.html b/index.html
index dfb6513..0deeb53 100644
--- a/index.html
+++ b/index.html
@@ -527,37 +527,37 @@
      cannot see the card move.
 
      Which of the two corner controls a screen gets is decided once, in
-     showPane(), rather than here as well: this rule used to hide #back on the
+     chromeFor(), rather than here as well: this rule used to hide #back on the
      card while showPane un-hid it, and two mechanisms for one fact is how they
      drift. */
-  /* On the two screens the menu owns, it loses its disc and grows to the size of
+  /* Wherever the menu shows, it loses its disc and grows to the size of
      the two verdicts on the card, so the set reads as one set. A bordered pill
      over a room reads as a control panel bolted to the picture, and the same
      button two sizes on two consecutive screens reads as two buttons: Enes,
      "in the 3rd picture the hamburger icon like the 3 lines is different, make
      image 3 match image 2". The drop shadow is what the disc was for, and it
-     works over a photograph and a night map alike. */
-  body.carding #menu, body.waying #menu, body.rooming #menu {
+     works over a photograph and a night map alike.
+     The arrow that takes the same corner on a phone is drawn the same way. As
+     a 44px disc at .6rem it sat 16px off the menu's centre, so going from the
+     card to a room moved the corner control and changed what it was. */
+  body #back, body #menu {
     border: 0; background: none; padding: 0;
     min-width: 60px; min-height: 60px; width: 60px; height: 60px;
     top: calc(var(--safe-t) + 1.1rem);
-    /* The column rule below is (1,0,0) and this is (1,1,1), so writing a bare
-       1.1rem here beat it on every window -- and these are the only two screens
-       the menu appears on, which made that rule dead. Measured at 1900px: the
-       hamburger sat at x=17 while the 512px column started at x=694. */
+    /* The column rule below is (1,0,0) and this is (1,0,1), so writing a bare
+       1.1rem here beat it on every window, which made that rule dead for the
+       menu. Measured at 1900px: the hamburger sat at x=17 while the 512px
+       column started at x=694. */
     left: max(1.1rem, env(safe-area-inset-left, 0px), calc(50% - var(--col) / 2 + .5rem));
   }
-  body.carding #menu .ico, body.waying #menu .ico, body.rooming #menu .ico {
+  #back .ico, #menu .ico {
     width: 40px; height: 40px; stroke-width: 2.1;
     filter: drop-shadow(0 1px 3px rgba(0,0,0,.9)) drop-shadow(0 0 10px rgba(0,0,0,.55));
   }
-  body.carding .m-panel, body.waying .m-panel, body.rooming .m-panel {
+  body .m-panel {
     top: calc(var(--safe-t) + 4.6rem);
     left: max(1.1rem, env(safe-area-inset-left, 0px), calc(50% - var(--col) / 2 + .5rem));
   }
-  /* The room keeps the established fixed Back arrow on a phone. Its menu and
-     panel-local Back control are the desktop pair below. */
-  body.rooming #menu { display: none; }
 
   /* The way: the map with the room lit on it, one plate naming the room, and the
      ranking peeked underneath. Enes on the schedule, "the list of other classes
@@ -568,6 +568,17 @@
      pointer through: the map is meant to be panned, and the plate is a label
      rather than a control. */
   #way { position: fixed; inset: 0; z-index: 2; pointer-events: none; }
+  /* The plate is a label and lets the map have the pointer; its Back is the one
+     control on it. Inset at both ends so the name stays centred on the plate. */
+  #way-plate { padding-inline: 3rem; }
+  #way-back {
+    position: absolute; top: 50%; left: .35rem; transform: translateY(-50%);
+    pointer-events: auto; appearance: none; border: 0; background: none;
+    color: var(--fg); width: 44px; height: 44px; padding: 0; border-radius: 999px;
+    display: flex; align-items: center; justify-content: center; cursor: pointer;
+  }
+  #way-back:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }
+  #way-back .ico { width: 26px; height: 26px; stroke-width: 2.1; }
 
   /* --- the answer --- */
   /* The sheet carries the column width itself, rather than running the full
@@ -784,7 +795,6 @@
     margin: 0; padding: .1rem 0 0;
     font-size: 1.05rem; letter-spacing: -.01em;
   }
-  .room-back { display: none; }
   .claim { margin: 0; padding: 0 1.1rem .35rem; font-weight: 650; }
   .claim .sub { display: block; font-weight: 400; color: var(--dim); font-size: .86rem; }
   .facts {
@@ -948,9 +958,9 @@
     .b-row:hover, .pick-row:hover { background: rgba(255,255,255,.05); }
     .bar-btn:hover { background: var(--card-hi); border-color: var(--line-hi); }
     .dstep:hover { color: var(--fg); }
-    /* The arrow is already a translucent pill over the map. Hovering makes it
-       opaque rather than lighter, so it does not read as a second state. */
-    #back:hover { background: var(--bg); border-color: var(--line-hi); }
+    /* The arrow is a bare glyph like the menu beside it, so hovering dims the
+       glyph rather than growing a disc it does not otherwise have. */
+    #back:hover .ico, #menu:hover .ico { opacity: .75; }
   }
 
   /* --- the display cutout, in landscape --- */
@@ -1028,21 +1038,12 @@
     }
     body:is(.has-bar) #sheet { bottom: calc(var(--bar-h, 0px) + 1rem); }
     #sheet .handle { display: none; }
-    #back, #menu, body.carding #menu, body.waying #menu, body.rooming #menu { left: 1.5rem; }
-    /* The menu owns a 60px target while Back owns a 44px target. Offset Back
-       by half that 16px difference so their glyphs keep the same corner centre
-       when moving between desktop screens. */
-    #back {
-      left: calc(1.5rem + 8px);
-      top: calc(var(--safe-t) + 1.1rem + 8px);
-    }
-    .m-panel, body.carding .m-panel, body.waying .m-panel, body.rooming .m-panel { left: 1.5rem; }
+    body #back, body #menu { left: 1.5rem; }
+    body .m-panel { left: 1.5rem; }
     #way-plate {
       left: 1.5rem; transform: none;
       width: min(30rem, calc(60vw - 3rem)); max-width: none;
     }
-    body.rooming #back { display: none; }
-    body.rooming #menu { display: flex; }
     #room .room-head {
       position: sticky; top: 0; z-index: 2;
       display: flex; align-items: center; gap: .75rem;
@@ -1055,6 +1056,10 @@
       width: 44px; padding: 0; justify-content: center;
     }
     #room .claim { padding-top: .75rem; }
+    /* The same control and the same inset as the room's header, so Back sits
+       in one place in the panel whichever pane is under it. */
+    #sheet-head { display: flex; flex: none; padding: 1rem 1.1rem .25rem; }
+    #sheet-back { display: flex; width: 44px; padding: 0; justify-content: center; }
 
     body.carding #sheet {
       left: 0; right: 0; top: 1.5rem; bottom: 1.5rem;
@@ -1145,7 +1150,7 @@
 <button id="back" hidden aria-label="Back to the question">
   <svg class="ico ico-mirror" aria-hidden="true"><use href="#i-back"/></svg>
 </button>
-<!-- The menu, on the two screens that have no back arrow. Enes: "the top left
+<!-- The menu, on the screens whose corner has no back arrow (chromeFor()). Enes: "the top left
      should have the 3 lines thing, and when pressed it should have choices like
      to go back or other stuff". A disclosure and not a menu ROLE: that role
      promises arrow-key navigation between the items, and announcing a keyboard
@@ -1173,6 +1178,12 @@
      plate over it. -->
 <section id="way" hidden>
   <div class="c-plate" id="way-plate">
+    <!-- The way is a step down from the card it was taken from, and its one
+         visible way back. It was Back inside the menu, under a grip only a
+         phone has. -->
+    <button type="button" id="way-back" hidden>
+      <svg class="ico ico-mirror" aria-hidden="true"><use href="#i-back"/></svg>
+    </button>
     <h2 class="c-b" id="way-name"></h2>
     <p class="c-facts" id="way-facts"></p>
   </div>
@@ -1215,6 +1226,13 @@ <h2 id="gate-h" tabindex="-1"></h2>
 
 <section id="sheet" hidden>
   <div class="handle" id="handle"><span class="grip"></span></div>
+  <!-- Back, in the panel, on a desktop: the corner keeps the menu there, and
+       the room has its own in its sticky header (chromeFor()). -->
+  <div id="sheet-head" hidden>
+    <button type="button" class="bar-btn room-back" id="sheet-back">
+      <svg class="ico ico-mirror" aria-hidden="true"><use href="#i-back"/></svg>
+    </button>
+  </div>
   <div id="origin" hidden>
     <button id="origin-where" class="bar-btn" type="button">
       <svg class="ico" aria-hidden="true"><use href="#i-pin"/></svg><span></span>
diff --git a/js/app.js b/js/app.js
index ca2afbc..a56f56b 100644
--- a/js/app.js
+++ b/js/app.js
@@ -282,6 +282,20 @@ function focusHeading(el) {
   el.focus({ preventScroll: true, focusVisible: false });
 }
 
+// The first thing on the screen showing now, for focus to land on when it was
+// reached from somewhere that took focus with it.
+function landFocus() {
+  const s = state.screen;
+  const el =
+    s === 'ask' ? document.querySelector('#ask .opt[aria-pressed="true"]')
+    : s === 'way' ? $('way-name')
+    : s === 'card' ? $('card-h') ?? $('c-top')
+    : s === 'list' ? $('list-h') ?? $('list').querySelector('.row.on, .row')
+    : $(`${s}-h`);
+  if (el?.matches('h1, h2')) focusHeading(el);
+  else el?.focus({ preventScroll: true });
+}
+
 // ---------------------------------------------------------------- rendering
 
 let flyoverStart = 0;
@@ -574,21 +588,38 @@ function attachMenu() {
     show(false);
   });
 
+  // Closing hands focus back to the menu button, and a choice that changes the
+  // screen then hides that button on a phone, which dropped a keyboard or
+  // screen reader user on the body. Where the choice lands, focus lands.
   const act = (id, go) => {
     $(id).onclick = () => {
+      const from = state.screen;
       show(false);
       go();
+      if (state.screen !== from) landFocus();
     };
   };
-  // Back first, because it is the one Enes named and the one both screens lack.
-  // history.back() rather than a screen: from the card it is the question, from
-  // the way it is the card that was taken, and both are the entry underneath.
-  act('m-back', () => history.back());
-  act('m-list', () => openList());
-  act('m-browse', () => openBrowse());
-  act('m-pick', () => openPick());
+  // Back first, because it is the one Enes named. history.back() rather than a
+  // screen: from the card it is the question, and that is the entry underneath.
+  // It arrives a task later, through popstate, so focus waits for it.
+  act('m-back', () => {
+    window.addEventListener('popstate', landFocus, { once: true });
+    history.back();
+  });
+  // A choice naming the screen directly underneath goes back to it rather than
+  // stacking a copy on top. On a desktop room opened from the list, See all
+  // rooms pushed a second list, and list, room, list, room was a loop Back had
+  // to walk one step at a time. Going back also keeps the row and the scroll.
+  const reach = (screen, open) => () => {
+    if (history.state?.from !== screen) return open();
+    window.addEventListener('popstate', landFocus, { once: true });
+    history.back();
+  };
+  act('m-list', reach('list', openList));
+  act('m-browse', reach('browse', openBrowse));
+  act('m-pick', reach('pick', openPick));
   act('m-recheck', () => refresh());
-  act('m-about', () => openAbout());
+  act('m-about', reach('about', openAbout));
 }
 
 function attachSheet() {
@@ -2132,9 +2163,9 @@ function commitPickedOrigin(origin) {
   state.query = '';
   $('find-q').value = '';
   // The picker replaces itself in history rather than stacking, so back still
-  // goes wherever the picker was opened from.
+  // goes wherever the picker was opened from, and the entry keeps saying where.
   const view = state.scheduled && state.rankable ? 'list' : 'near';
-  history.replaceState({ v: view }, '', cleanUrl());
+  history.replaceState({ v: view, from: history.state?.from }, '', cleanUrl());
   if (view === 'list') {
     showList();
     answer();
@@ -2652,7 +2683,7 @@ function roomHtml(id) {
       : '';
 
   return `<div class="room-head">
-      <button type="button" class="bar-btn room-back" id="room-back">
+      <button type="button" class="bar-btn room-back" id="room-back" hidden>
         <svg class="ico ico-mirror" aria-hidden="true"><use href="#i-back"/></svg>
       </button>
       <h2 id="room-h" tabindex="-1">${esc(bname)} ${esc(room.n ?? '')}</h2>
@@ -2942,15 +2973,11 @@ function showPane(name) {
   $('origin').hidden = !originBarOn(name);
   $('ask').hidden = true;
   $('sheet').hidden = false;
-  // The card and desktop room screen keep the menu over the map. The room's
-  // back arrow lives in its panel on desktop; CSS keeps this global arrow on
-  // mobile, where the room still fills the sheet.
-  $('back').hidden = name === 'card';
-  $('menu').hidden = name !== 'card' && name !== 'room';
   closeMenu();
   document.body.classList.remove('asking');
   const arrived = state.screen !== name;
   state.screen = name;
+  paintChrome();
   syncPaneTouch();
   // Arriving re-composes the camera for the strip THIS screen leaves. Without
   // it the view stays fitted for the screen behind: leaving a room slid the walk
@@ -2969,13 +2996,12 @@ function reframe() {
 
 function showAsk() {
   state.screen = 'ask';
+  paintChrome();
   $('way').hidden = true;
   $('ask').hidden = false;
   document.body.classList.add('asking');
   document.body.classList.remove('carding', 'rooming', 'waying');
   $('sheet').hidden = true;
-  $('back').hidden = true;
-  $('menu').hidden = true;
   closeMenu();
   for (const id of PANES) $(id).hidden = id !== 'list';
   state.settled = false;
@@ -3006,7 +3032,6 @@ function showCard() {
   // until you have said yes to a room.
   state.selected = null;
   showPane('card');
-  $('back').setAttribute('aria-label', 'Back to the question');
   $('card').scrollTop = 0;
   paintCard();
   sheetHeight();
@@ -3022,12 +3047,6 @@ function showList(view = null) {
   state.selected = remembered;
   state.listScroll = Number.isFinite(view?.scroll) ? Math.max(0, view.scroll) : 0;
   showPane('list');
-  // openList() pushes over whatever was showing, and the menu can open the list
-  // from the way as well as from the card.
-  $('back').setAttribute(
-    'aria-label',
-    history.state?.from === 'way' ? 'Back to the way' : 'Back to the card',
-  );
   $('list').scrollTop = state.listScroll;
   markRows();
   sheetHeight();
@@ -3036,7 +3055,6 @@ function showList(view = null) {
 function showNear() {
   state.listScroll = 0;
   showPane('near');
-  $('back').setAttribute('aria-label', 'Back to the question');
   paintNear(nearReason());
   $('near').scrollTop = 0;
   sheetHeight();
@@ -3048,7 +3066,6 @@ function showPick() {
   loadShorts();
   state.pickPoint = null;
   showPane('pick');
-  $('back').setAttribute('aria-label', 'Back without picking a building');
   paintPick();
   $('pick').scrollTop = 0;
   setSheet(restNow(), true);
@@ -3059,7 +3076,6 @@ function showBrowse(view = null) {
   state.browseBuilding = view?.building ?? null;
   state.browseQuery = view?.query ?? state.browseQuery;
   showPane('browse');
-  $('back').setAttribute('aria-label', 'Back');
   paintBrowse();
   $('browse').scrollTop = Number.isFinite(view?.scroll) ? Math.max(0, view.scroll) : 0;
   sheetHeight();
@@ -3067,7 +3083,6 @@ function showBrowse(view = null) {
 
 function showAbout() {
   showPane('about');
-  $('back').setAttribute('aria-label', 'Back');
   setSheet(restNow(), true);
   paintAbout();
 }
@@ -3078,8 +3093,10 @@ function showAbout() {
 // heading and re-snaps the sheet to rest, and a sheet that jumps back to rest
 // under a reader is worse than a stale number.
 function wireRoom(id) {
-  $('room-back').setAttribute('aria-label', roomBackLabel());
   $('room-back').onclick = () => history.back();
+  // A repaint writes the button back unhidden, and only this knows whether the
+  // room shows it.
+  paintChrome();
   attachBearing(id);
   // A week either way, and no clamp. Past the term's own bounds the grid comes
   // back empty and the sentence over it says the schedule does not reach there.
@@ -3157,11 +3174,6 @@ function showRoom(id, { keepDay = false } = {}) {
   // mechanism: #list keeps its scrollTop because it was never destroyed.
   showPane('room');
   $('room').scrollTop = 0;
-  // Back pops to the entry underneath this one, and openRoom wrote down which
-  // screen that is. Outside scheduled hours the room screen opens over the
-  // buildings screen, and the label promised a room list that is not there.
-  $('back').setAttribute('aria-label', roomBackLabel());
-
   // frame() below runs only when the room is one of the ranked rows. Opened
   // from a link or out of hours it is not, and the footprint still has to light.
   frames.wake();
@@ -3179,14 +3191,70 @@ function showRoom(id, { keepDay = false } = {}) {
   }
 }
 
-function roomBackLabel() {
-  return history.state?.from === 'near'
-    ? 'Back to the nearest buildings'
-    : history.state?.from === 'browse'
-      ? 'Back to browse buildings'
-      : history.state?.from === 'way'
-        ? 'Back to the way'
-        : 'Back to the room list';
+// Which controls lead out of a screen, decided here and nowhere else. There are
+// two places a way out can sit: the corner over the map, which holds the menu
+// or the Back arrow and never both, and the panel, which holds a Back of its
+// own on the screens whose corner the menu keeps. Decided in showPane, showAsk
+// and showWay, with CSS hiding and showing the room's pair per breakpoint as
+// well, the four drifted: two mechanisms for one fact is how they do.
+function chromeFor(screen, desk = splitQuery?.matches === true) {
+  if (screen === 'ask') return { corner: null, panel: false };
+  if (screen === 'card') return { corner: 'menu', panel: false };
+  // The way keeps the menu, for the list, the picker and Check again, and its
+  // Back is on the plate naming the room it leaves.
+  if (screen === 'way') return { corner: 'menu', panel: true };
+  // On a desktop the corner is over the map and the panel is across the
+  // window from it, so the corner keeps the menu on every screen and Back goes
+  // in the panel, beside what it leaves. On a phone the sheet is under the
+  // corner, and a screen that is a step down from another gets the arrow.
+  if (desk) return { corner: 'menu', panel: true };
+  return { corner: 'back', panel: false };
+}
+
+function paintChrome() {
+  const { corner, panel } = chromeFor(state.screen);
+  const label = backLabel();
+  $('back').hidden = corner !== 'back';
+  $('menu').hidden = corner !== 'menu';
+  $('back').setAttribute('aria-label', label);
+  // The room has its own, in its sticky header beside the room's name, and the
+  // way has its own on its plate.
+  const room = state.screen === 'room';
+  const way = state.screen === 'way';
+  $('sheet-head').hidden = !panel || room || way;
+  $('sheet-back').setAttribute('aria-label', label);
+  $('way-back').hidden = !(panel && way);
+  $('way-back').setAttribute('aria-label', label);
+  // The menu's Back is for the screens with no other, and names where it goes
+  // like every other Back does.
+  $('m-back').hidden = panel || corner === 'back';
+  $('m-back').textContent = label;
+  const own = $('room-back');
+  if (own) {
+    own.hidden = !(panel && room);
+    own.setAttribute('aria-label', label);
+  }
+}
+
+// What Back reaches, in words, for every control that goes there. The entry
+// underneath is the one Back lands on, and every entry records which screen
+// that is, so the label is read off the entry rather than written once per
+// screen: written per screen, the list said "Back to the card" when the menu
+// had opened it from a room, and a picked origin said it over the way.
+const BACK_TO = {
+  ask: 'Back to the question',
+  card: 'Back to the card',
+  list: 'Back to the room list',
+  way: 'Back to the way',
+  room: 'Back to the room',
+  near: 'Back to the nearest buildings',
+  browse: 'Back to browse buildings',
+  about: 'Back to what Vacant knows',
+};
+
+function backLabel(entry = history.state) {
+  if (entry?.v === 'pick') return 'Back without picking a building';
+  return BACK_TO[entry?.from] ?? 'Back';
 }
 
 // Where the room is: the map with the footprint lit, an arrow to it, one plate
@@ -3226,8 +3294,6 @@ function showWay(id, view = null) {
   $('origin').hidden = true;
   $('ask').hidden = true;
   $('sheet').hidden = false;
-  $('back').hidden = true;
-  $('menu').hidden = false;
   $('way').hidden = false;
   closeMenu();
   document.body.classList.remove('asking', 'carding', 'rooming');
@@ -3236,6 +3302,7 @@ function showWay(id, view = null) {
   document.body.classList.add('waying');
   const arrived = state.screen !== 'way';
   state.screen = 'way';
+  paintChrome();
   syncPaneTouch();
   paintWay(selectedId, r);
   markRows();
@@ -3292,7 +3359,7 @@ function paintWay(id, r) {
 // dismiss travel is the sheet's own, unchanged: it calls toAsk(), which is
 // history.back(), and from here that is one step.
 function openWay(id) {
-  const view = { v: 'way', room: id, selected: id, scroll: $('list').scrollTop };
+  const view = { v: 'way', from: state.screen, room: id, selected: id, scroll: $('list').scrollTop };
   history.pushState(view, '', `?room=${encodeURIComponent(id)}`);
   showWay(id, view);
 }
@@ -3314,12 +3381,12 @@ function choose(min) {
   if (!state.rankable) return;
   if (!state.scheduled) {
     if (state.screen !== 'near') {
-      history.pushState({ v: 'near' }, '', cleanUrl());
+      history.pushState({ v: 'near', from: 'ask' }, '', cleanUrl());
       showNear();
     }
     return;
   }
-  if (state.screen === 'ask') history.pushState({ v: 'card' }, '', cleanUrl());
+  if (state.screen === 'ask') history.pushState({ v: 'card', from: 'ask' }, '', cleanUrl());
   // Ranked BEFORE the screen is shown. The other way round, paintCard() ran once
   // against the previous answer -- on the first duration of a session that is no
   // rows at all, so the reader got "That is all of them. You went through 0
@@ -3379,7 +3446,7 @@ function openList() {
 }
 
 function openPick() {
-  history.pushState({ v: 'pick' }, '', cleanUrl());
+  history.pushState({ v: 'pick', from: state.screen }, '', cleanUrl());
   showPick();
 }
 
@@ -3387,18 +3454,18 @@ function openBrowse() {
   state.browseBuilding = null;
   state.browseQuery = '';
   state.selected = null;
-  const view = { v: 'browse', building: null, query: '', scroll: 0 };
+  const view = { v: 'browse', from: state.screen, building: null, query: '', scroll: 0 };
   history.pushState(view, '', cleanUrl());
   showBrowse(view);
 }
 
 function openAbout() {
-  history.pushState({ v: 'about' }, '', cleanUrl());
+  history.pushState({ v: 'about', from: state.screen }, '', cleanUrl());
   showAbout();
 }
 
 function openNear() {
-  history.pushState({ v: 'near' }, '', cleanUrl());
+  history.pushState({ v: 'near', from: state.screen }, '', cleanUrl());
   showNear();
 }
 
@@ -3417,12 +3484,12 @@ function openWantedRoom() {
   // without the app's own controls sending someone back to the referring site.
   history.replaceState({ v: 'ask' }, '', cleanUrl());
   if (state.scheduled) {
+    history.pushState({ v: 'card', from: 'ask' }, '', cleanUrl());
     showCard();
     answer();
-    history.pushState({ v: 'card' }, '', cleanUrl());
   } else {
+    history.pushState({ v: 'near', from: 'ask' }, '', cleanUrl());
     showNear();
-    history.pushState({ v: 'near' }, '', cleanUrl());
   }
   openRoom(wanted);
   return true;
@@ -3464,8 +3531,13 @@ function refresh() {
   answer();
   if (!held) return;
   if (state.results.some((r) => r.id === held)) showWay(held);
-  else {
-    history.replaceState({ v: 'card' }, '', cleanUrl());
+  else if (history.state?.from === 'card') {
+    // The card is already the entry underneath. Rewriting the way's own entry
+    // into a second card left two in a row, and the next Back looked like it
+    // did nothing. popstate paints the card answer() has just rebuilt.
+    history.back();
+  } else {
+    history.replaceState({ v: 'card', from: history.state?.from }, '', cleanUrl());
     showCard();
   }
 }
@@ -3909,6 +3981,8 @@ window.addEventListener('DOMContentLoaded', () => {
     b.onclick = () => choose(b.dataset.min);
   }
   $('back').onclick = () => history.back();
+  $('sheet-back').onclick = () => history.back();
+  $('way-back').onclick = () => history.back();
   $('gate-go').onclick = () => openNear();
   $('ask-pick').onclick = () => openPick();
   $('note-pick').onclick = () => openPick();
@@ -3951,6 +4025,9 @@ window.addEventListener('DOMContentLoaded', () => {
     // The root font size can change with the zoom level, and the side panel's
     // width is in rem.
     remPx = 0;
+    // Crossing the desktop breakpoint moves Back between the corner and the
+    // panel without a screen change to re-decide it.
+    paintChrome();
     if (state.screen !== 'ask') sheetHeight();
     // surface() reallocates the backing store on the next frame and the band
     // moves with the height, so a resize that does not reach the loop leaves a
diff --git a/scripts/test/screens.test.mjs b/scripts/test/screens.test.mjs
index dcd88b0..8c08e2c 100644
--- a/scripts/test/screens.test.mjs
+++ b/scripts/test/screens.test.mjs
@@ -866,8 +866,8 @@ test('a room deep link keeps every app Back press inside Vacant', () => {
   // the second visible Back button sends the reader to that external page.
   const open = bodyOf('openWantedRoom');
   const ask = open.indexOf("history.replaceState({ v: 'ask' }");
-  const card = open.indexOf("history.pushState({ v: 'card' }");
-  const near = open.indexOf("history.pushState({ v: 'near' }");
+  const card = open.indexOf("history.pushState({ v: 'card', from: 'ask' }");
+  const near = open.indexOf("history.pushState({ v: 'near', from: 'ask' }");
   const room = open.indexOf('openRoom(wanted)');
   assert.ok(ask >= 0, 'the direct link has no question entry underneath it');
   assert.ok(card > ask && near > ask, 'a landing screen is not stacked over the question');
@@ -1302,17 +1302,30 @@ test('the back button on the room screen names the pane back lands on', () => {
   const open = bodyOf('openRoom');
   assert.match(open, /pushState\(\{[^}]*from: state\.screen/);
 
-  // The pairing, not the presence. Every string is in this function either way,
-  // so separate matches all hold with the arms swapped, which is the reported
-  // defect back again. Three arms now: the way opens rooms too, and it is not
-  // the room list.
-  const label = bodyOf('roomBackLabel');
-  assert.match(label, /from === 'near'\s*\?\s*'Back to the nearest buildings'/);
-  assert.match(label, /from === 'way'\s*\?\s*'Back to the way'\s*:\s*'Back to the room list'/);
+  // The pairing, not the presence: a table keyed by the screen underneath, so
+  // the near and list arms cannot be swapped back the way they once were.
+  assert.match(APP, /near: 'Back to the nearest buildings'/);
+  assert.match(APP, /list: 'Back to the room list'/);
+  assert.match(APP, /way: 'Back to the way'/);
+  assert.match(bodyOf('paintChrome'), /own\.setAttribute\('aria-label', label\)/);
   assert.match(bodyOf('roomHtml'), /id="room-back"/);
   assert.match(bodyOf('wireRoom'), /\$\('room-back'\)\.onclick = \(\) => history\.back\(\)/);
 });
 
+test('every history entry says which screen it was opened from', () => {
+  // Back lands on the entry underneath, and every label, guard and menu choice
+  // that needs to know where that is reads it off this entry. An entry without
+  // it is a screen whose way out has to be guessed.
+  for (const fn of ['openRoom', 'openList', 'openPick', 'openBrowse', 'openAbout', 'openNear', 'openWay']) {
+    assert.match(bodyOf(fn), /from: state\.screen/, `${fn} pushes an entry with no from`);
+  }
+  // From the question, the two screens a duration opens.
+  assert.match(bodyOf('choose'), /\{ v: 'near', from: 'ask' \}/);
+  assert.match(bodyOf('choose'), /\{ v: 'card', from: 'ask' \}/);
+  // The picker replaces itself, and keeps saying where it was opened from.
+  assert.match(bodyOf('commitPickedOrigin'), /replaceState\(\{ v: view, from: history\.state\?\.from \}/);
+});
+
 test('the desktop room header keeps its identity and aligned Back control while the schedule scrolls', () => {
   const css = readFileSync(join(ROOT, 'index.html'), 'utf8');
   assert.match(
@@ -1423,7 +1436,7 @@ test('a duration opens one room, not the ranking', () => {
   const choose = bodyOf('choose');
   assert.match(choose, /showCard\(\)/);
   assert.doesNotMatch(choose, /showList\(\)/, 'a duration still opens the list');
-  assert.match(choose, /history\.pushState\(\{ v: 'card' \}/);
+  assert.match(choose, /history\.pushState\(\{ v: 'card', from: 'ask' \}/);
   // And the card is a pane of the same sheet, so it inherits the drag, the
   // dismiss and the covered map rather than reimplementing them.
   assert.match(APP, /const PANES = \['card', 'list'/);
@@ -1527,10 +1540,10 @@ test('the swipe is not the only way to answer the card', () => {
   assert.match(swipe, /toAsk\(\)/);
   assert.match(bodyOf('paintCard'), /Swipe down to start over/);
   // No back arrow either. It was a third piece of chrome on a photograph, and
-  // the corner belongs to the menu now. Decided in showPane and nowhere else:
+  // the corner belongs to the menu now. Decided in chromeFor and nowhere else:
   // a CSS rule hiding it while showPane un-hid it is two mechanisms for one
   // fact, which is how they drift.
-  assert.match(bodyOf('showPane'), /\$\('back'\)\.hidden = name === 'card'/);
+  assert.match(bodyOf('chromeFor'), /screen === 'card'\) return \{ corner: 'menu', panel: false \}/);
   const css = readFileSync(join(ROOT, 'index.html'), 'utf8');
   assert.equal(/body\.carding #back \{/.test(css), false, 'the CSS hides #back as well');
 
@@ -1548,20 +1561,43 @@ test('neither screen without a back arrow is a dead end', () => {
   // is no browser chrome behind them either, so each needs its own way out.
   // The card has the downward throw and the way has the sheet's grip, and both
   // have the menu, whose first item is the one Enes asked for by name.
-  assert.match(bodyOf('attachMenu'), /act\('m-back', \(\) => history\.back\(\)\)/);
+  assert.match(bodyOf('attachMenu'), /act\('m-back', \(\) => \{[\s\S]*?history\.back\(\);\n  \}\);/);
+  // And a choice that moves the screen moves focus with it, rather than to a
+  // menu button that screen hides.
+  assert.match(bodyOf('attachMenu'), /if \(state\.screen !== from\) landFocus\(\);/);
+  assert.match(bodyOf('attachMenu'), /addEventListener\('popstate', landFocus, \{ once: true \}\)/);
+  // A choice naming the screen underneath goes back to it, not a copy on top.
+  const choices = bodyOf('attachMenu');
+  assert.match(choices, /if \(history\.state\?\.from !== screen\) return open\(\);/);
+  for (const [id, screen, open] of [['m-list', 'list', 'openList'], ['m-browse', 'browse', 'openBrowse'], ['m-pick', 'pick', 'openPick'], ['m-about', 'about', 'openAbout']]) {
+    assert.match(choices, new RegExp(`act\\('${id}', reach\\('${screen}', ${open}\\)\\)`), `${id} stacks a copy again`);
+  }
   assert.match(APP, /attachMenu\(\);/);
   // Which means the way needs a history entry of its own for back to land on.
   assert.match(bodyOf('openWay'), /const view = \{ v: 'way'/);
   assert.match(bodyOf('openWay'), /history\.pushState\(view/);
 
-  // One corner, two controls, never both, and the menu is on the two screens
-  // the arrow left.
-  const pane = bodyOf('showPane');
-  assert.match(pane, /\$\('back'\)\.hidden = name === 'card'/);
-  assert.match(pane, /\$\('menu'\)\.hidden = name !== 'card' && name !== 'room'/);
-  const way = bodyOf('showWay');
-  assert.match(way, /\$\('back'\)\.hidden = true/);
-  assert.match(way, /\$\('menu'\)\.hidden = false/);
+  // The way's Back is on its plate, not only in the menu, and the menu's own
+  // Back names where it goes and stands down wherever another Back shows.
+  assert.match(bodyOf('chromeFor'), /screen === 'way'\) return \{ corner: 'menu', panel: true \}/);
+  assert.match(bodyOf('paintChrome'), /\$\('way-back'\)\.hidden = !\(panel && way\)/);
+  assert.match(bodyOf('paintChrome'), /\$\('m-back'\)\.hidden = panel \|\| corner === 'back'/);
+  assert.match(bodyOf('paintChrome'), /\$\('m-back'\)\.textContent = label/);
+  assert.match(APP, /\$\('way-back'\)\.onclick = \(\) => history\.back\(\)/);
+  assert.match(readFileSync(join(ROOT, 'index.html'), 'utf8'), /#way-back \{[^}]*pointer-events: auto/);
+
+  // One corner, two controls, never both, decided in one function that every
+  // way onto a screen calls, and re-decided when the breakpoint is crossed.
+  const paint = bodyOf('paintChrome');
+  assert.match(paint, /\$\('back'\)\.hidden = corner !== 'back'/);
+  assert.match(paint, /\$\('menu'\)\.hidden = corner !== 'menu'/);
+  for (const fn of ['showPane', 'showAsk', 'showWay', 'wireRoom']) {
+    assert.match(bodyOf(fn), /paintChrome\(\)/, `${fn} decides its own corner again`);
+    assert.doesNotMatch(bodyOf(fn), /\$\('(back|menu)'\)\.hidden =/, `${fn} decides its own corner again`);
+  }
+  assert.match(APP, /remPx = 0;\n\s*\/\/ Crossing the desktop breakpoint[^\n]*\n[^\n]*\n\s*paintChrome\(\);/);
+  assert.doesNotMatch(readFileSync(join(ROOT, 'index.html'), 'utf8'), /body\.rooming #(back|menu) \{ display/,
+    'the CSS decides the room\'s corner as well');
 
   // A panel that outlives the screen it was opened on is a set of choices about
   // somewhere the reader has left.
@@ -1572,11 +1608,18 @@ test('neither screen without a back arrow is a dead end', () => {
   // A disclosure, not a menu: role="menu" promises arrow keys move between the
   // items, and the app does not implement that.
   const css = readFileSync(join(ROOT, 'index.html'), 'utf8');
-  // The desktop hamburger has a 60px target and Back has a 44px target. Back
-  // needs half that 16px difference on both axes for the two glyph centres to
-  // occupy the same corner when one screen replaces the other.
-  assert.match(css, /#back \{\s*left:\s*calc\(1\.5rem \+ 8px\);\s*top:\s*calc\(var\(--safe-t\) \+ 1\.1rem \+ 8px\);\s*\}/);
-  assert.match(css, /#back, #menu, body\.carding #menu, body\.waying #menu, body\.rooming #menu \{ left: 1\.5rem; \}/);
+  // On a desktop the corner never changes hands: it keeps the menu on every
+  // screen, so a second click on it cannot land on Back, and every pane's Back
+  // is in the panel, beside what it leaves.
+  assert.match(bodyOf('chromeFor'), /if \(desk\) return \{ corner: 'menu', panel: true \}/);
+  assert.match(bodyOf('paintChrome'), /\$\('sheet-head'\)\.hidden = !panel \|\| room/);
+  assert.match(css, /<div id="sheet-head" hidden>\s*<button type="button" class="bar-btn room-back" id="sheet-back">/);
+  assert.match(APP, /\$\('sheet-back'\)\.onclick = \(\) => history\.back\(\)/);
+  assert.match(css, /body #back, body #menu \{ left: 1\.5rem; \}/);
+  // On a phone the arrow takes the menu's corner, size and drawing, so the
+  // corner control stays put when one screen hands it to the other.
+  assert.match(css, /body #back, body #menu \{\s*border: 0; background: none; padding: 0;\s*min-width: 60px;/);
+  assert.match(css, /#back \.ico, #menu \.ico \{\s*width: 40px; height: 40px;/);
   assert.doesNotMatch(css, /body\.carding #menu \{[^}]*calc\(50% - 36rem/,
     'the hamburger jumps from the viewport corner to the centred card edge');
   assert.match(css, /<button id="menu"[^>]*aria-expanded="false"[^>]*aria-controls="menu-pop"/s);
@@ -1672,7 +1715,10 @@ test('checking again on the way does not switch the map off under the plate', ()
   // Back to the same room if it survived the re-rank, and to the card if a
   // class has taken it.
   assert.match(refresh, /state\.results\.some\(\(r\) => r\.id === held\)\) showWay\(held\)/);
-  assert.match(refresh, /history\.replaceState\(\{ v: 'card' \}/);
+  // The card the way was taken from is the entry underneath, so it steps back
+  // onto it rather than rewriting the way into a second card on top of it.
+  assert.match(refresh, /else if \(history\.state\?\.from === 'card'\) \{[^}]*history\.back\(\);/);
+  assert.match(refresh, /history\.replaceState\(\{ v: 'card', from: history\.state\?\.from \}/);
 });
 
 test('the menu holds the keyboard as well as the screen', () => {
@@ -1795,18 +1841,19 @@ test('back names the screen it lands on, at every step of the answer', () => {
   // Its accessible name has to name the screen it reaches rather than reading
   // "Back", and there are three steps now: the card is what a duration opens,
   // the list is one tap behind the card, and a room is behind either.
-  assert.match(
-    bodyOf('showCard'),
-    /\$\('back'\)\.setAttribute\('aria-label', 'Back to the question'\)/,
-  );
-  // The list is reached from the card and, through the menu, from the way, so
-  // its label is a pair rather than a string.
+  // One label for every screen, read off the entry Back lands on, and set
+  // where the screen is shown rather than once per screen.
+  assert.match(APP, /ask: 'Back to the question'/);
+  assert.match(APP, /card: 'Back to the card'/);
+  assert.match(bodyOf('backLabel'), /BACK_TO\[entry\?\.from\]/);
+  assert.match(bodyOf('backLabel'), /entry\?\.v === 'pick'\) return 'Back without picking a building'/);
+  assert.match(bodyOf('paintChrome'), /\$\('back'\)\.setAttribute\('aria-label', label\)/);
+  for (const fn of ['showCard', 'showList', 'showNear', 'showPick', 'showBrowse', 'showAbout', 'showRoom']) {
+    assert.doesNotMatch(bodyOf(fn), /\$\('back'\)\.setAttribute/, `${fn} writes its own Back label again`);
+  }
+  // The list is reached from the card and, through the menu, from the way.
   assert.match(bodyOf('openList'), /from: state\.screen/);
   assert.match(bodyOf('openList'), /pushState\(view/);
-  assert.match(
-    bodyOf('showList'),
-    /from === 'way'\s*\?\s*'Back to the way'\s*:\s*'Back to the card'/,
-  );
   const html = readFileSync(join(ROOT, 'index.html'), 'utf8');
   assert.match(html, /id="back"[^>]*aria-label="Back to the question"/);
   // The four .opt buttons are what back lands on, and they are the four the