/*
 * Scroll performance contract.
 *
 * Every route is a fixed, independently scrollable surface (see
 * code-freeze.css). This sheet only adds the compositor hints that keep those
 * surfaces smooth on mobile; it never changes their geometry.
 *
 * `will-change: transform` is deliberately NOT applied to the surfaces: a
 * transformed ancestor becomes the containing block of its `position: fixed`
 * descendants, which would pin every in-view overlay (payment sheets,
 * Tableaux modals, account workspace) to the scrolled content instead of the
 * viewport. `will-change: scroll-position` gives the browser the same
 * "promote this scroller" hint without that side effect, and heavy off-screen
 * cards opt into `content-visibility: auto` instead.
 */

.cid-layout-surface,
#results,
#categoriesView,
#croixViewContainer,
#tableauxViewContainer,
#matrixCalculatorPanel,
#profileViewContainer,
#anticipationViewContainer,
#resultatAideViewContainer,
#globalStatisticsViewContainer,
#virtualAssistantViewContainer,
#historyViewContainer,
#notificationCenter {
  /* overflow-y: auto is already enforced per route by code-freeze.css. */
  -webkit-overflow-scrolling: touch;
  will-change: scroll-position;
  scroll-behavior: auto;
  /* Vertical panning is handled by the browser without waiting on scripts;
     pinch-zoom stays available for reading the numbers. */
  touch-action: pan-y pinch-zoom;
  overscroll-behavior-y: contain;
}

/* Tableaux grids, satellite tables and the draggable Croix also pan sideways
   (same rule as scroll-stability.js applies to the document on Croix). */
#tableauxViewContainer,
#croixViewContainer,
#historyViewContainer {
  touch-action: pan-x pan-y pinch-zoom;
}

/*
 * No backdrop blur anywhere. A blurred fixed header, bottom bar or overlay
 * forces the GPU to re-blur everything that scrolls beneath it on every
 * frame, which is what made modest phones skip frames or freeze. Surfaces
 * that relied on it now use near-opaque rgba colours in their own
 * stylesheets; this rule keeps a future rule or inline style from bringing
 * the cost back.
 */
*,
*::before,
*::after {
  -webkit-backdrop-filter: none !important;
  backdrop-filter: none !important;
}

/*
 * Off-screen publications skip layout and paint until they approach the
 * viewport. `auto` in contain-intrinsic-size remembers the real height after
 * the first render, so the scrollbar does not jump. Only the older days of
 * the feed and the lower Anticipé cards opt in; Croix and Tableaux cards are
 * excluded because their number fitting measures the live geometry.
 */
#cid-home-feed > .cid-fb-post.is-historical:not([data-post-type="cross"]),
.anticipation-feed > [data-anticipation-feature]:nth-child(n + 3):not([data-anticipation-feature="croix"]):not([data-anticipation-feature^="tableaux-"]) {
  content-visibility: auto;
  contain-intrinsic-size: auto 480px;
}

/*
 * Instant taps everywhere. `manipulation` removes the ~300 ms double-tap-zoom
 * wait on every interactive element (buttons, links, category tiles, cards,
 * tabs) while keeping panning and pinch-zoom; the grey iOS tap flash is
 * replaced by each component's own :active state.
 */
a,
button,
summary,
label,
select,
input[type="button"],
input[type="submit"],
input[type="checkbox"],
input[type="radio"],
[role="button"],
[role="tab"],
[role="menuitem"],
[data-category],
.category-item,
.category-card,
.categories-grid > *,
.cid-fb-post,
.tableaux-history-button {
  touch-action: manipulation;
  -webkit-tap-highlight-color: transparent;
}

/* Universal back affordance: instant tap response, no double-tap zoom delay. */
.cid-back-button,
[data-cid-back-button],
#cidSectionBack {
  touch-action: manipulation;
  -webkit-tap-highlight-color: transparent;
  cursor: pointer;
}

.cid-back-button:active,
[data-cid-back-button]:active,
#cidSectionBack:active {
  opacity: .72;
}

/* Low-end devices: drop decorative motion that competes with scrolling. */
@media (prefers-reduced-motion: reduce) {
  .cid-layout-surface *,
  #results *,
  #anticipationViewContainer *,
  #tableauxViewContainer * {
    animation-duration: .01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: .01ms !important;
    scroll-behavior: auto !important;
  }
}