/* ── 07 · SHARED COMPONENTS ──
   The CSS counterpart of `shared/`: the things more than one section uses.

   - Panel slide and the margin arrows, driven by shared/tab-slide.js. Used by
     People, Research, Publications and Information.
   - The pager, driven by shared/pager.js. Used by News and Publications.

   It sits at 07 so every section sheet comes after it and can override —
   which is also why a shared component must not be parked in a section's own
   file, where the sections before it could never reach it.

   Part of the numbered set in css/ — the sheets are one stylesheet cut into
   pieces and index.html links them in this order. Order is the cascade: a
   rule here loses to the same-specificity rule in any later file. */

/* ── Shared tab panel transition (driven by shared/tab-slide.js) ── */
@keyframes tab-panel-leave {
    from {
        transform: translateX(0);
        opacity: 1;
    }
    to {
        transform: translateX(-60%);
        opacity: 0;
    }
}

@keyframes tab-panel-leave-back {
    from {
        transform: translateX(0);
        opacity: 1;
    }
    to {
        transform: translateX(60%);
        opacity: 0;
    }
}

@keyframes tab-panel-enter {
    from {
        opacity: 0.25;
    }
    to {
        opacity: 1;
    }
}

/* forwards so the panel stays gone for the frame between the animation ending
   and the script setting `hidden`. */
.tab-panel--leaving {
    animation: tab-panel-leave 0.32s cubic-bezier(0.4, 0, 1, 1) forwards;
    will-change: transform, opacity;
}

.tab-panel--leaving-back {
    animation: tab-panel-leave-back 0.32s cubic-bezier(0.4, 0, 1, 1) forwards;
    will-change: transform, opacity;
}

.tab-panel--entering {
    animation: tab-panel-enter 0.3s ease-out;
}

/* ── Margin tab navigation (see shared/tab-slide.js) ── */
.tab-margin-host {
    position: relative;
}

/* The strip between the section edge and its centred content column. */
.tab-margin-nav {
    position: absolute;
    top: 0;
    bottom: 0;
    z-index: 2;
    width: calc((100% - var(--content-inline-size)) / 2);
    padding: 0;
    border: none;
    background: none;
    cursor: pointer;
    appearance: none;
}

.tab-margin-nav--prev {
    left: 0;
}

.tab-margin-nav--next {
    right: 0;
}

/* Sticky so the affordance stays in view down a long section. Visible at rest
   — it is the only sign the margins are clickable — and grows on hover. */
.tab-margin-nav__chevron {
    position: sticky;
    top: 50vh;
    display: block;
    width: 0.95rem;
    height: 0.95rem;
    margin: 0 auto;
    border-right: 2px solid rgba(17, 17, 17, 0.55);
    border-bottom: 2px solid rgba(17, 17, 17, 0.55);
    opacity: 0.32;
    transition:
        opacity 0.2s ease,
        translate 0.2s ease,
        scale 0.25s cubic-bezier(0.22, 1, 0.36, 1);
}

.tab-margin-nav--prev .tab-margin-nav__chevron {
    rotate: 135deg;
}

.tab-margin-nav--next .tab-margin-nav__chevron {
    rotate: -45deg;
}

.tab-margin-nav:hover .tab-margin-nav__chevron,
.tab-margin-nav:focus-visible .tab-margin-nav__chevron {
    opacity: 0.8;
    scale: 1.45;
}

.tab-margin-nav--prev:hover .tab-margin-nav__chevron {
    translate: -0.25rem 0;
}

.tab-margin-nav--next:hover .tab-margin-nav__chevron {
    translate: 0.25rem 0;
}

/* Below this the margin is just the page gutter — too narrow to aim at, and
   it would swallow taps meant for the content. */
@media (max-width: 1300px) {
    .tab-margin-nav {
        display: none;
    }
}

/* ── The pager (see shared/pager.js) ──
   Two arrows and "Page N of M", used by News and Publications. It replaced a
   numbered strip on the Publications side: a row of page buttons grows with
   the archive and reflows every time a filter changes the count, and "jump to
   page 6" is not a thing anyone wants from a list they have just re-sorted.
   This form is the same size whatever the count.

   Two custom properties are the whole of its theming, so a section colours it
   by declaring them next to its own accent tokens rather than by writing
   selectors here. The fallbacks are a neutral grey, so an undeclared section
   gets something legible instead of nothing. */
.pager {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 1rem;
    padding-top: 0.4rem;
}

/* `display: flex` above outranks the UA rule for the attribute — the same trap
   as .research-tab-panel, .join-stage and .pub-card. */
.pager[hidden] {
    display: none;
}

.pager__btn {
    display: grid;
    place-items: center;
    width: 2.2rem;
    height: 2.2rem;
    border: 1px solid color-mix(in srgb, var(--pager-accent, #8a857c) 34%, transparent);
    border-radius: 999px;
    background: transparent;
    color: var(--pager-ink, #4a4640);
    font-size: 0.95rem;
    line-height: 1;
    cursor: pointer;
    transition:
        background 0.16s ease,
        border-color 0.16s ease,
        opacity 0.16s ease;
}

.pager__btn:hover:not(:disabled) {
    background: color-mix(in srgb, var(--pager-accent, #8a857c) 16%, transparent);
    border-color: var(--pager-accent, #8a857c);
}

.pager__btn:disabled {
    opacity: 0.3;
    cursor: default;
}

/* A fixed width, so the row does not shuffle sideways when the count goes from
   one digit to two. */
.pager__position {
    font-family: "Helvetica Neue", Helvetica, Arial, sans-serif;
    font-size: 0.72rem;
    font-weight: 600;
    letter-spacing: 0.12em;
    text-transform: uppercase;
    color: #6c675f;
    min-width: 8rem;
    text-align: center;
}

@media (prefers-reduced-motion: reduce) {
    .pager__btn {
        transition: none;
    }
}