/* The ribbon shell. Copied from OpenCalc's `webapp/ribbon.css` at `b23c67c`
 * (webapp/README.md, owner instruction 42) and trimmed to what this viewer
 * draws: the parked menu bar and toolbar, combos, the phone command bar,
 * colour swatches and the embed rules are not here yet. OpenCalc's notes:
 *
 * The Excel shell (UX-SHELL-07, its docs/95), built to its owner-approved
 * prototype.
 *
 * Metrics are Excel's proportions, not invented ones: a 44px title bar, a 34px
 * tab strip, a ribbon card whose Classic band is three 24px rows (72px) plus
 * padding, 16px icons in small controls and 24px icons in a large button's
 * 72px column. Simplified is one 32px row.
 *
 * Every colour is a token `editor.css` defines, so both themes and an
 * integrator's accent apply. Nothing here names a colour.
 *
 * Loaded always, active only under `.op-chrome-ribbon`. */

.op-ribbon { display: none; }

/* A filled accent surface carries white text in both themes. The dark theme's
 * accent is a light blue meant for text and outlines, and its paired text
 * colour is near-black — black on blue, which read badly. Deepened a quarter
 * toward black, the accent holds white at about 5:1 in dark and well above in
 * light, the same treatment `.op-btn.primary` uses. Tokens: ribbon.tokens.css. */

/* ── Title bar ─────────────────────────────────────────────────────────── */

/* No `display` here: hiding the header (a host's `hide: header`, the desktop
 * shell, an embed, the collapse button) is decided by `editor.css`, and a
 * display value at this specificity would silently override every one. */
.op-chrome-ribbon .app-header {
  height: 44px; box-sizing: border-box; align-items: center; gap: 4px;
  padding: 0 12px; background: var(--op-surface-color); border-bottom: 0;
}
.op-chrome-ribbon .app-header .doc-identity { display: flex; align-items: baseline; gap: 8px; margin-left: 8px; min-width: 0; }
.op-chrome-ribbon .app-header button.doc-name { font-weight: 600; font-size: 13px; }
.op-chrome-ribbon .app-header .doc-state { font-size: 12px; color: var(--op-muted-text-color); }
.op-chrome-ribbon .app-header .header-right { display: flex; align-items: center; gap: 8px; margin-left: 0; }

.rb-qat { display: flex; align-items: center; gap: 2px; margin-left: 8px; }
.rb-qat .rb-btn.rb-s { min-width: 30px; height: 30px; }

.rb-search {
  flex: 1 1 0; min-width: 0; max-width: 420px; margin: 0 auto; height: 30px; box-sizing: border-box;
  display: flex; align-items: center; gap: 8px; padding: 0 10px;
  background: var(--op-background-color); border: 1px solid var(--op-control-border-color); border-radius: 6px;
  color: var(--op-muted-text-color);
}
.rb-search:focus-within { border-color: var(--op-accent-color); box-shadow: 0 0 0 2px var(--op-accent-ring); }
.rb-search-input {
  flex: 1; min-width: 0; border: 0; outline: none; background: transparent;
  font: inherit; font-size: 13px; color: var(--op-text-color);
}
.rb-search-input::-webkit-search-cancel-button { display: none; }

.rb-share {
  height: 30px; display: inline-flex; align-items: center; gap: 6px; padding: 0 12px;
  border: 0; border-radius: 6px; background: var(--rb-accent-fill); color: var(--rb-on-accent);
  font: inherit; font-size: 13px; font-weight: 600; cursor: pointer;
}
.rb-share[hidden] { display: none; }
.rb-share:hover { background: color-mix(in srgb, var(--op-accent-color), #000 35%); }
.rb-share:focus-visible { outline: 2px solid var(--op-accent-color); outline-offset: 2px; }

/* ── Tab strip ─────────────────────────────────────────────────────────── */

.op-chrome-ribbon .op-ribbon { display: block; background: var(--op-surface-color); user-select: none; }

.op-chrome-ribbon .rb-tabs {
  height: 34px; display: flex; align-items: flex-end; gap: 2px; padding: 0 12px;
}
/* The roster, when a host has hidden the title bar it normally sits in. */
.op-chrome-ribbon .rb-tabs > .presence { align-self: center; flex: none; }
.op-chrome-ribbon .rb-tablist { display: flex; align-items: flex-end; gap: 2px; min-width: 0; overflow-x: auto; scrollbar-width: none; }
.op-chrome-ribbon .rb-tablist::-webkit-scrollbar { display: none; }
.op-chrome-ribbon .rb-file,
.op-chrome-ribbon .rb-tab {
  position: relative; height: 30px; padding: 0 12px; border: 0; border-radius: 6px 6px 0 0;
  background: transparent; color: var(--op-text-color); font: inherit; font-size: 13px;
  white-space: nowrap; cursor: pointer;
}
.op-chrome-ribbon .rb-file { color: var(--op-accent-color); font-weight: 600; }
.op-chrome-ribbon .rb-file:hover,
.op-chrome-ribbon .rb-tab:hover { background: var(--op-border-color); }
.op-chrome-ribbon .rb-tab.is-on { color: var(--op-accent-color); font-weight: 600; box-shadow: inset 0 -3px 0 var(--op-accent-color); }
.op-chrome-ribbon .rb-file:focus-visible,
.op-chrome-ribbon .rb-tab:focus-visible { outline: 2px solid var(--op-accent-color); outline-offset: -2px; }

/* ── Ribbon band ───────────────────────────────────────────────────────── */

.op-chrome-ribbon .rb-band {
  position: relative; margin: 0 8px; background: var(--op-background-color);
  border: 1px solid var(--op-border-color); border-radius: 8px;
}
.op-chrome-ribbon .rb-panel {
  display: flex; align-items: stretch; height: 78px; box-sizing: border-box;
  padding: 3px 28px 3px 4px; overflow: hidden;
}
.op-chrome-ribbon .rb-panel[hidden] { display: none; }
.op-chrome-ribbon .op-ribbon.rb-labels-captions .rb-panel { height: 96px; }

.op-chrome-ribbon .rb-group {
  position: relative; display: flex; flex-direction: column; flex: none;
  padding: 0 8px; border-right: 1px solid var(--op-border-color);
}
.op-chrome-ribbon .rb-group:last-child { border-right: 0; }
.op-chrome-ribbon .rb-items { display: flex; align-items: center; gap: 4px; flex: 1; }
/* Group names are kept in the DOM as the accessible name and drawn only when
 * File > Options > Ribbon labels asks for them (docs/95 rule 1). */
.op-chrome-ribbon .rb-cap {
  display: none; height: 18px; align-items: center; justify-content: center;
  font-size: 11px; color: var(--op-muted-text-color); white-space: nowrap;
}
.op-chrome-ribbon .op-ribbon.rb-labels-captions .rb-cap { display: flex; }
.op-chrome-ribbon .rb-launch { display: none; }
/* A launcher sits in the caption row, as in Excel; with names off it would sit
 * on top of the group's last button, so it goes with them. Format Cells is
 * still Ctrl+1 and on the right-click menu. */
.op-chrome-ribbon .op-ribbon.rb-labels-captions .rb-launch { display: flex; }
.op-chrome-ribbon .rb-launch {
  position: absolute; right: 2px; bottom: 2px; width: 16px; height: 16px; padding: 0;
  align-items: center; justify-content: center;
  border: 0; border-radius: 3px; background: transparent; color: var(--op-muted-text-color); cursor: pointer;
}
.op-chrome-ribbon .rb-launch svg { transform: rotate(-45deg); }
.op-chrome-ribbon .rb-launch:hover { background: var(--op-surface-color); color: var(--op-text-color); }

.op-chrome-ribbon .rb-rows { display: flex; flex-direction: column; justify-content: center; gap: 6px; height: 72px; }
.op-chrome-ribbon .rb-rows[data-rows="3"] { gap: 0; }
.op-chrome-ribbon .rb-row { display: flex; align-items: center; gap: 2px; }

/* Buttons */
.op-chrome-ribbon .rb-btn,
.rb-qat .rb-btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 2px;
  border: 0; border-radius: 4px; background: transparent; color: var(--op-text-color);
  font: inherit; cursor: pointer; padding: 0 4px; box-sizing: border-box;
}
.op-chrome-ribbon .rb-btn[hidden] { display: none; }
.op-chrome-ribbon .rb-s { height: 24px; min-width: 28px; }
.op-chrome-ribbon .rb-s[aria-haspopup] { min-width: 36px; }
.op-chrome-ribbon .rb-l {
  flex-direction: column; justify-content: center; gap: 4px;
  min-width: 40px; max-width: 72px; height: 72px; padding: 4px;
}
.op-chrome-ribbon .rb-label { display: none; font-size: 11px; line-height: 13px; text-align: center; }
.op-chrome-ribbon .op-ribbon.rb-labels-full .rb-l .rb-label { display: block; }
.op-chrome-ribbon .rb-btn:hover:not(:disabled),
.rb-qat .rb-btn:hover:not(:disabled) { background: var(--op-surface-color); }
.op-chrome-ribbon .rb-btn:active:not(:disabled) { background: var(--op-border-color); }
.op-chrome-ribbon .rb-btn:focus-visible,
.rb-qat .rb-btn:focus-visible { outline: 2px solid var(--op-accent-color); outline-offset: -2px; }
.op-chrome-ribbon .rb-btn[aria-pressed="true"] { background: var(--op-accent-soft); color: var(--op-accent-color); }
.op-chrome-ribbon .rb-btn:disabled,
.rb-qat .rb-btn:disabled { opacity: 0.4; cursor: default; }
.rb-ico { display: block; flex: none; fill: currentColor; }
.rb-caret { display: block; flex: none; fill: currentColor; color: var(--op-muted-text-color); }

/* Ribbon Display Options, bottom right of the band (XL-UX-093): Excel's ˅. */
.op-chrome-ribbon .rb-layout {
  position: absolute; right: 6px; bottom: 6px; width: 24px; height: 24px; padding: 0;
  display: flex; align-items: center; justify-content: center;
  border: 0; border-radius: 4px; background: transparent; color: var(--op-muted-text-color); cursor: pointer;
}
.op-chrome-ribbon .rb-layout:hover { background: var(--op-surface-color); }
/* Ribbon Display Options (XL-UX-093). Tabs only: the band leaves the layout,
 * so the grid gets its height; a clicked tab floats it over the grid. */
.op-chrome-ribbon .op-ribbon { position: relative; }
.op-chrome-ribbon .op-ribbon.rb-tabs-only .rb-band { display: none; }
.op-chrome-ribbon .op-ribbon.rb-tabs-only.rb-peek .rb-band {
  display: block; position: absolute; left: 0; right: 0; top: 100%; z-index: 30;
  box-shadow: var(--op-popover-shadow);
}
.rb-pop-sep { height: 1px; margin: 4px 0; background: var(--op-border-color); }

/* Folding: a group that does not fit becomes one large button. */
.op-chrome-ribbon .rb-folded { display: none; }
.op-chrome-ribbon .rb-group.is-folded > .rb-items,
.op-chrome-ribbon .rb-group.is-folded > .rb-cap,
.op-chrome-ribbon .rb-group.is-folded > .rb-launch { display: none; }
.op-chrome-ribbon .rb-group.is-folded > .rb-folded { display: inline-flex; }
/* A folded group is named, as in Excel: the name is a group's, not a button
 * label, so it shows whenever group names do. */
.op-chrome-ribbon .op-ribbon.rb-labels-captions .rb-folded .rb-label { display: block; }
.rb-fold-pop { padding: 8px; }
.rb-fold-pop .rb-items { display: flex; align-items: center; gap: 4px; }

/* Simplified: one row, every control small, no captions. */
.op-chrome-ribbon .op-ribbon.rb-simplified .rb-panel { height: 44px; padding-top: 6px; padding-bottom: 6px; }
.op-chrome-ribbon .op-ribbon.rb-simplified .rb-cap,
.op-chrome-ribbon .op-ribbon.rb-simplified .rb-launch,
.op-chrome-ribbon .op-ribbon.rb-simplified .rb-label { display: none; }
.op-chrome-ribbon .op-ribbon.rb-simplified .rb-group { padding: 0 6px; }
.op-chrome-ribbon .op-ribbon.rb-simplified .rb-rows,
.op-chrome-ribbon .op-ribbon.rb-simplified .rb-row { display: contents; }
.op-chrome-ribbon .op-ribbon.rb-simplified .rb-items { gap: 2px; }
.op-chrome-ribbon .op-ribbon.rb-simplified .rb-btn { height: 32px; min-width: 32px; flex-direction: row; max-width: none; padding: 0 4px; }
.op-chrome-ribbon .op-ribbon.rb-simplified .rb-l .rb-ico { width: 18px; height: 18px; }
.op-chrome-ribbon .op-ribbon.rb-simplified .rb-folded .rb-ico { width: 18px; height: 18px; }

/* ── PowerPoint's ribbon (UX-003, docs/53) ────────────────────────────────
 * What makes the band read as PowerPoint's rather than a toolbar: large
 * buttons labelled under their icon, small ones labelled beside it where
 * PowerPoint labels them (Cut, Copy, Layout, Shape Fill…), the Font and Size
 * combos, in-ribbon galleries, the group name under every group, and the
 * dialog launcher in its corner. */
.op-chrome-ribbon .rb-l { min-width: 42px; max-width: 72px; gap: 3px; justify-content: flex-start; padding: 6px 3px 2px; }
.op-chrome-ribbon .rb-l .rb-ico { margin-top: 2px; }
.op-chrome-ribbon .rb-l .rb-label { white-space: normal; overflow-wrap: break-word; }
.op-chrome-ribbon .rb-l .rb-caret { margin-top: -2px; }
.op-chrome-ribbon .rb-btn.rb-text { justify-content: flex-start; gap: 5px; padding: 0 6px 0 4px; }
.op-chrome-ribbon .rb-btn.rb-text .rb-label { display: block; font-size: 12px; line-height: 14px; white-space: nowrap; text-align: left; }
.op-chrome-ribbon .op-ribbon.rb-labels-captions .rb-panel { height: 100px; }
.op-chrome-ribbon .rb-rows { height: 76px; }
.op-chrome-ribbon .rb-rows[data-rows="2"] { gap: 10px; }
.op-chrome-ribbon .rb-rows + .rb-rows { margin-left: 2px; }
.op-chrome-ribbon .rb-row { gap: 1px; }
.op-chrome-ribbon .rb-cap { height: 18px; font-size: 11px; }
.op-chrome-ribbon .rb-group { padding: 0 4px; margin: 4px 0 0; }

/* The dialog launcher, bottom right, in the caption row (PowerPoint's ↘). */
.op-chrome-ribbon .rb-group:has(> .rb-launch) .rb-cap { padding-right: 16px; }
.op-chrome-ribbon .rb-launch { right: 2px; bottom: 1px; }
.op-chrome-ribbon .rb-launch:disabled { opacity: .45; cursor: default; }
.op-chrome-ribbon .rb-launch:focus-visible { outline: 2px solid var(--op-accent-color); outline-offset: -2px; }

/* Combos: Font and Font Size. */
.rb-combo { flex: none; height: 24px; margin-right: 2px; }
.rb-combo-btn {
  width: 100%; height: 100%; display: flex; align-items: center; justify-content: space-between; gap: 4px;
  padding: 0 4px 0 6px; box-sizing: border-box; border: 1px solid var(--op-control-border-color); border-radius: 4px;
  background: var(--op-background-color); color: var(--op-text-color); font: inherit; font-size: 12px; cursor: pointer;
}
.rb-combo-btn:hover:not(:disabled) { border-color: var(--op-border-hover-color); }
.rb-combo-btn:disabled { cursor: default; color: var(--op-disabled-color); background: var(--op-surface-color); }
.rb-combo-btn:disabled .rb-caret { opacity: .5; }
.rb-combo-val { overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }

/* In-ribbon galleries: Themes, Variants, Transitions, Animations, Shape Styles. */
.rb-gallery {
  display: flex; align-items: stretch; height: 70px; margin: 3px 2px 0; box-sizing: border-box;
  border: 1px solid var(--op-border-color); border-radius: 4px; background: var(--op-background-color);
}
.rb-gal-tiles { display: flex; flex-wrap: wrap; align-content: flex-start; gap: 2px; padding: 3px; overflow: hidden; max-width: 392px; max-height: 64px; }
.rb-gal-tile {
  flex: none; width: 62px; display: flex; flex-direction: column; align-items: center; justify-content: center; gap: 3px;
  padding: 2px; border: 1px solid transparent; border-radius: 3px; background: transparent; color: var(--op-text-color);
  font: inherit; font-size: 11px; cursor: pointer;
}
.rb-gal-tile:hover:not(:disabled) { border-color: var(--op-accent-color); }
.rb-gal-tile[aria-selected="true"] { border-color: var(--op-accent-color); background: var(--op-accent-soft); }
.rb-gal-tile:disabled { cursor: default; color: var(--op-muted-text-color); }
.rb-gal-tile:disabled .rb-ico { opacity: .55; }
.rb-gal-name { white-space: nowrap; }
.rb-gal-swatch {
  position: relative; width: 56px; height: 56px; box-sizing: border-box; display: flex; align-items: center; justify-content: center;
  border: 1px solid var(--op-border-color); border-radius: 2px; overflow: hidden;
}
.rb-gal-aa { font-size: 17px; font-weight: 600; }
.rb-gal-bar { position: absolute; left: 0; right: 0; bottom: 0; height: 6px; }
.rb-gal-tile:disabled .rb-gal-swatch { opacity: .7; }
.rb-gal-more {
  flex: none; width: 18px; display: flex; align-items: center; justify-content: center; padding: 0;
  border: 0; border-left: 1px solid var(--op-border-color); background: transparent; color: var(--op-muted-text-color); cursor: pointer;
}
.rb-gal-more:hover:not(:disabled) { background: var(--op-surface-color); }
.rb-gal-more:disabled { cursor: default; opacity: .6; }
.op-chrome-ribbon .op-ribbon.rb-simplified .rb-gallery { height: 32px; margin: 0; }
.op-chrome-ribbon .op-ribbon.rb-simplified .rb-gal-tile { width: 32px; }
.op-chrome-ribbon .op-ribbon.rb-simplified .rb-gal-tile:nth-child(n+4),
.op-chrome-ribbon .op-ribbon.rb-simplified .rb-gal-name { display: none; }
.op-chrome-ribbon .op-ribbon.rb-simplified .rb-gal-swatch { width: 26px; height: 24px; }
.op-chrome-ribbon .op-ribbon.rb-simplified .rb-gal-aa { font-size: 11px; }
.op-chrome-ribbon .op-ribbon.rb-simplified .rb-gal-bar { height: 3px; }
.op-chrome-ribbon .op-ribbon.rb-simplified .rb-gal-tiles { padding: 1px 3px; }
.op-chrome-ribbon .op-ribbon.rb-simplified .rb-gal-tile .rb-ico { width: 18px; height: 18px; }
/* Simplified keeps a few words, as PowerPoint's single line does for New Slide,
 * Layout or Shapes; the stacks lose theirs. */
.op-chrome-ribbon .op-ribbon.rb-simplified .rb-combo { height: 28px; }
.op-chrome-ribbon .op-ribbon.rb-simplified .rb-panel { height: 44px; }
.op-chrome-ribbon .op-ribbon.rb-simplified .rb-group { margin: 0; }
.op-chrome-ribbon .op-ribbon.rb-simplified .rb-btn.rb-text .rb-label { display: none; }

/* A contextual tab (Shape Format): its name in the accent, as PowerPoint's. */
.op-chrome-ribbon .rb-tab.rb-tab-ctx { color: var(--op-accent-color); font-weight: 600; }
.op-chrome-ribbon .rb-tab.rb-tab-ctx[hidden] { display: none; }
.op-chrome-ribbon .rb-tab.rb-tab-ctx::before {
  content: ""; position: absolute; left: 6px; right: 6px; top: 1px; height: 2px; border-radius: 1px; background: var(--op-accent-color); opacity: .5;
}

/* The tab row's right end: Comments, Editing, Present, Share. */
.op-chrome-ribbon .rb-tabs { align-items: center; }
.op-chrome-ribbon .rb-tablist { align-self: flex-end; flex: 1 1 auto; }
.rb-tabs-end { display: flex; align-items: center; gap: 6px; margin-left: auto; padding-left: 12px; flex: none; }
.rb-end-btn, .rb-present-main, .rb-present-drop {
  height: 30px; display: inline-flex; align-items: center; gap: 6px; padding: 0 10px; box-sizing: border-box;
  border: 1px solid var(--op-control-border-color); border-radius: 6px; background: var(--op-background-color);
  color: var(--op-text-color); font: inherit; font-size: 13px; cursor: pointer; white-space: nowrap;
}
.rb-end-btn:hover:not(:disabled), .rb-present-main:hover:not(:disabled), .rb-present-drop:hover { background: var(--op-surface-color); }
.rb-end-btn:disabled, .rb-present-main:disabled { color: var(--op-disabled-color); cursor: default; }
.rb-end-btn:focus-visible, .rb-present-main:focus-visible, .rb-present-drop:focus-visible { outline: 2px solid var(--op-accent-color); outline-offset: 1px; }
.rb-present { display: inline-flex; }
.rb-present-main { border-radius: 6px 0 0 6px; border-right: 0; font-weight: 600; }
.rb-present-drop { border-radius: 0 6px 6px 0; padding: 0 6px; }
.rb-tabs-end .rb-share { border: 0; }
.rb-tabs-end .rb-share:hover:not(:disabled) { background: color-mix(in srgb, var(--op-accent-color), #000 35%); }
.rb-tabs-end .rb-share:disabled { background: var(--rb-accent-fill); color: var(--rb-on-accent); opacity: .55; }
@media (max-width: 1100px) { .rb-end-label { display: none; } .rb-present-main .rb-end-label { display: inline; } }
@media (max-width: 760px) { .rb-tabs-end .rb-mode, .rb-tabs-end .rb-end-btn:first-child { display: none; } }

/* Right-click menus. */
.rb-ctx { min-width: 220px; }
/* Compact rows as in PowerPoint's menus: the label sets the height, not a tall line box. */
.rb-ctx .rb-pop-item { min-height: 26px; line-height: 1.2; padding: 0 10px; }
.rb-ctx .rb-pop-sep { margin: 3px 6px; }

/* KeyTips */
.op-chrome-ribbon .rb-tip {
  position: absolute; left: 50%; bottom: -6px; transform: translateX(-50%);
  min-width: 16px; padding: 1px 4px; border-radius: 3px; z-index: 2;
  background: var(--op-text-color); color: var(--op-background-color);
  font-size: 11px; font-weight: 600; line-height: 14px; text-align: center;
}

/* ── Popovers (dropdowns, combos, search results) ─────────────────────── */

.rb-pop { position: fixed; min-width: 180px; max-height: 60vh; }
.rb-pop-item {
  display: flex; align-items: center; justify-content: space-between; gap: 16px;
  min-height: 28px; padding: 0 10px; border: 0; border-radius: 6px; background: transparent;
  color: var(--op-text-color); font: inherit; font-size: 13px; text-align: left; cursor: pointer;
}
.rb-pop-item:hover:not(:disabled), .rb-pop-item:focus-visible { background: var(--op-surface-color); outline: none; }
.rb-pop-item:disabled { opacity: 0.45; cursor: default; }
.rb-pop-item[aria-checked="true"], .rb-pop-item[aria-selected="true"] { color: var(--op-accent-color); font-weight: 600; }
.rb-pop-key { color: var(--op-muted-text-color); font-size: 12px; }
.rb-pop-empty { padding: 8px 10px; color: var(--op-muted-text-color); font-size: 13px; }

/* ── File page ─────────────────────────────────────────────────────────
 * Excel's Backstage: a rail of destinations and a page of described choices.
 * The rail is a soft tint of the accent over the surface, not a slab of it —
 * a full-strength accent rail read as a glaring block in dark mode and left
 * its labels and Back arrow at poor contrast. The accent marks only the page
 * that is open. */
.rb-backstage {
  position: fixed; inset: 0; z-index: 70; display: flex;
  background: var(--op-background-color); color: var(--op-text-color);
}
.rb-backstage[hidden] { display: none; }
.rb-rail {
  width: 232px; flex: none; display: flex; flex-direction: column; gap: 2px; padding: 12px 10px;
  background: color-mix(in srgb, var(--op-accent-color) 9%, var(--op-surface-color));
  border-right: 1px solid var(--op-border-color); color: var(--op-text-color);
}
.rb-back {
  width: 36px; height: 36px; margin: 0 0 12px 2px; display: flex; align-items: center; justify-content: center;
  border: 0; border-radius: 50%; background: transparent; color: var(--op-text-color); cursor: pointer;
}
.rb-back:hover, .rb-rail-item:hover { background: color-mix(in srgb, var(--op-accent-color) 14%, transparent); }
.rb-rail-item {
  height: 40px; display: flex; align-items: center; gap: 12px; padding: 0 14px;
  border: 0; border-radius: 6px; background: transparent; color: var(--op-text-color);
  font: inherit; font-size: 14px; text-align: left; cursor: pointer;
}
.rb-rail-item .rb-ico { color: var(--op-muted-text-color); }
.rb-rail-item.is-on { background: var(--rb-accent-fill); color: var(--rb-on-accent); font-weight: 600; }
.rb-rail-item.is-on .rb-ico { color: inherit; }
.rb-back:focus-visible, .rb-rail-item:focus-visible { outline: 2px solid var(--op-accent-color); outline-offset: 1px; }

.rb-pane { flex: 1; min-width: 0; padding: 36px 56px; overflow: auto; }
.rb-page { max-width: 720px; }
.rb-page[hidden] { display: none; }
.rb-page-title { margin: 0 0 24px; font-size: 28px; font-weight: 600; letter-spacing: -0.01em; }
.rb-section { display: flex; flex-direction: column; gap: 8px; }
.rb-section + .rb-section { margin-top: 28px; }
.rb-section-title { margin: 0 0 2px; font-size: 13px; font-weight: 600; color: var(--op-muted-text-color); }

/* New: template tiles. */
.rb-tiles { display: flex; flex-wrap: wrap; gap: 16px; }
.rb-tile {
  width: 168px; display: flex; flex-direction: column; gap: 8px; padding: 0;
  border: 0; background: transparent; color: var(--op-text-color); font: inherit; text-align: left; cursor: pointer;
}
.rb-tile-art {
  width: 168px; height: 118px; display: flex; align-items: center; justify-content: center;
  border: 1px solid var(--op-control-border-color); border-radius: 8px; color: var(--op-accent-color);
  background: var(--op-surface-color);
}
.rb-tile:hover .rb-tile-art { border-color: var(--op-accent-color); }
.rb-tile:focus-visible .rb-tile-art { outline: 2px solid var(--op-accent-color); outline-offset: 2px; }
.rb-tile-label { font-size: 13px; }
/* Blank Presentation: a title slide in miniature, our own drawing. */
.rb-tile-slide { flex-direction: column; gap: 6px; background: #fff; color: #5f6368; }
.rb-tile-title { font-size: 12px; padding: 2px 8px; border: 1px dashed #c3c9cc; }
.rb-tile-sub { font-size: 8px; padding: 1px 6px; border: 1px dashed #d5d9dc; }
/* PowerPoint's File rail is a band of the app's colour with white text; ours
 * is the accent, deepened, per `DEC-03`. */
.rb-rail { background: var(--rb-accent-fill); color: var(--rb-on-accent); border-right: 0; }
.rb-rail .rb-back, .rb-rail .rb-rail-item, .rb-rail .rb-rail-item .rb-ico { color: var(--rb-on-accent); }
.rb-rail .rb-back:hover, .rb-rail .rb-rail-item:hover { background: rgba(255, 255, 255, .14); }
.rb-rail .rb-rail-item.is-on { background: rgba(0, 0, 0, .22); }
.rb-rail .rb-back:focus-visible, .rb-rail .rb-rail-item:focus-visible { outline-color: #fff; }

/* Described choices: icon, name, one line of what it does. */
.rb-page-list {
  display: flex; flex-direction: column; border: 1px solid var(--op-border-color); border-radius: 8px;
  background: var(--op-background-color); overflow: hidden;
}
.rb-page-item {
  min-height: 56px; display: flex; align-items: center; gap: 14px; padding: 10px 16px;
  border: 0; background: transparent; color: var(--op-text-color);
  font: inherit; text-align: left; cursor: pointer;
}
.rb-page-item + .rb-page-item { border-top: 1px solid var(--op-border-color); }
.rb-page-item > .rb-ico { color: var(--op-accent-color); }
.rb-page-item:hover { background: var(--op-surface-color); }
.rb-page-item:focus-visible { outline: 2px solid var(--op-accent-color); outline-offset: -2px; }
.rb-item-text { display: flex; flex-direction: column; gap: 2px; min-width: 0; }
.rb-item-label { font-size: 14px; font-weight: 500; }
.rb-item-desc { font-size: 12.5px; color: var(--op-muted-text-color); }

/* Options: a label and one control per row. */
.rb-options { display: flex; flex-direction: column; }
.rb-option {
  display: flex; align-items: center; justify-content: space-between; gap: 16px; flex-wrap: wrap;
  padding: 14px 16px; border: 1px solid var(--op-border-color); border-radius: 8px; background: var(--op-background-color);
}
.rb-option-label { font-size: 14px; font-weight: 500; }
.rb-seg { display: inline-flex; padding: 2px; border-radius: 8px; background: var(--op-surface-color); border: 1px solid var(--op-border-color); }
.rb-seg-btn {
  height: 30px; padding: 0 14px; border: 0; border-radius: 6px; background: transparent;
  color: var(--op-text-color); font: inherit; font-size: 13px; cursor: pointer;
}
.rb-seg-btn:hover { background: color-mix(in srgb, var(--op-accent-color) 10%, transparent); }
.rb-seg-btn[aria-checked="true"] { background: var(--op-background-color); color: var(--op-accent-color); font-weight: 600; box-shadow: 0 1px 2px rgba(15, 18, 22, .12); }
.rb-seg-btn:focus-visible { outline: 2px solid var(--op-accent-color); outline-offset: 1px; }

@media (max-width: 600px) {
  .rb-backstage { flex-direction: column; }
  .rb-rail { width: auto; flex-direction: row; overflow-x: auto; padding: 8px; border-right: 0; border-bottom: 1px solid var(--op-border-color); }
  .rb-back { margin: 0 4px 0 0; flex: none; }
  .rb-rail-item { flex: none; }
  .rb-pane { padding: 20px 16px; }
}

@media (prefers-reduced-motion: reduce) {
  .op-chrome-ribbon .rb-layout svg { transition: none; }
}

/* Phones: the band scrolls sideways rather than overflowing the page. */
@media (max-width: 600px) {
  .rb-search, .rb-share span { display: none; }
  .op-chrome-ribbon .rb-panel { overflow-x: auto; scrollbar-width: none; }
  .op-chrome-ribbon .rb-panel::-webkit-scrollbar { display: none; }
}


/* KeyTips, as OpenCalc's (`ribbon.css` at `b23c67c`): a dark badge under each tab
 * and button while they are shown (`UX-003`). */
.op-chrome-ribbon .rb-tab, .op-chrome-ribbon .rb-file,
.op-chrome-ribbon .rb-btn, .op-chrome-ribbon .rb-combo-btn,
.op-chrome-ribbon .rb-gal-more, .op-chrome-ribbon .rb-launch { position: relative; }
.op-chrome-ribbon .rb-tip {
  position: absolute; left: 50%; bottom: -6px; transform: translateX(-50%);
  min-width: 16px; padding: 1px 4px; border-radius: 3px; z-index: 5;
  background: var(--op-text-color, #222); color: var(--op-background-color, #fff);
  font-size: 11px; font-weight: 600; line-height: 14px; text-align: center;
  pointer-events: none; white-space: nowrap;
}
.op-chrome-ribbon .rb-tip.rb-tip-dim { opacity: 0.25; }

/* File > Open and New: Recent (`PAR-19`). */
.op-recent-row { display: flex; align-items: center; gap: 4px; padding-right: 8px; }
.op-recent-row + .op-recent-row { border-top: 1px solid var(--op-border-color); }
.op-recent-row .rb-page-item { flex: 1; min-width: 0; }
.op-recent-act { border: 1px solid var(--op-border-color); background: transparent; color: var(--op-text-color); font: inherit; font-size: 12px; padding: 4px 10px; border-radius: 4px; cursor: pointer; }
.op-recent-act:hover { background: var(--op-surface-color); }
.op-recent-empty { color: var(--op-muted-text-color); font-size: 13px; }
/* File > New: a template tile shows its theme's accents (`PAR-18`). */
.rb-tile-art .dz-swatches { width: 70%; }