/* Motion enhances the existing layout; no content depends on an animation to be visible. */
:root {
    --xmain-motion-ease: cubic-bezier(.22, .68, .25, 1);
    --xmain-motion-fast: 180ms;
    --xmain-motion-medium: 320ms;
}

.xmain-header {
    transition: box-shadow var(--xmain-motion-medium) ease, border-color var(--xmain-motion-medium) ease;
}
.xmain-header.is-scrolled {
    box-shadow: 0 5px 24px rgb(32 59 53 / 7%);
    border-bottom-color: #d2ddd5;
}
.xmain-nav__list a { position: relative; }
.xmain-nav__list a::after {
    content: "";
    position: absolute;
    right: 10px;
    bottom: 4px;
    left: 10px;
    height: 1px;
    background: currentColor;
    transform: scaleX(0);
    transform-origin: left;
    transition: transform var(--xmain-motion-medium) var(--xmain-motion-ease);
}
.xmain-nav__list a:focus-visible::after,
.xmain-nav__list a[aria-current="page"]::after { transform: scaleX(1); }

body.xmain-site :is(.xmain-button, .sp-button, .xmp-button, .xb-header-contact, .xmain-wechat-card, .xmp-manuscript-panel button) {
    transition: transform var(--xmain-motion-fast) var(--xmain-motion-ease),
        background-color var(--xmain-motion-fast) ease, border-color var(--xmain-motion-fast) ease,
        color var(--xmain-motion-fast) ease, box-shadow var(--xmain-motion-fast) ease;
}
body.xmain-site :is(.xmain-button, .sp-button, .xmp-button, .xb-header-contact, .xmain-wechat-card, .xmp-manuscript-panel button):not(:disabled):active {
    transform: translateY(1px) scale(.985);
}
:is(.xmain-nav__list a, .xb-more-links a, .xb-mobile-secondary a, .xb-footer-columns a, .sp-entry-nav a, .sp-product-lines a) {
    transition: color var(--xmain-motion-fast) ease, background-color var(--xmain-motion-fast) ease;
}
:is(.xb-offer, .xb-card, .sp-offer, .xb-journal-card, .xb-portal-grid a, .xmain-ebook-card > a) {
    transition: transform var(--xmain-motion-medium) var(--xmain-motion-ease),
        border-color var(--xmain-motion-medium) ease, box-shadow var(--xmain-motion-medium) ease;
}
:is(.xb-text-link span, .xb-portal-grid em, .sp-text-link span, .sp-course-meta b, .xmain-ebook-card__action > span) {
    display: inline-block;
    transition: transform var(--xmain-motion-medium) var(--xmain-motion-ease);
}
.xb-more summary::after { display: inline-block; transition: transform 220ms ease; }
.xb-more[open] summary::after { transform: rotate(180deg); }
.xmain-menu-toggle span[aria-hidden="true"] {
    transform-origin: center;
    transition: transform 240ms var(--xmain-motion-ease), opacity 160ms ease;
}
.xmain-menu-toggle[aria-expanded="true"] span:nth-child(1) { transform: translateY(8px) rotate(45deg); }
.xmain-menu-toggle[aria-expanded="true"] span:nth-child(2) { opacity: 0; }
.xmain-menu-toggle[aria-expanded="true"] span:nth-child(3) { transform: translateY(-8px) rotate(-45deg); }

@media (max-width: 1120px) {
    .xmain-mobile-panel {
        transition: opacity 220ms ease, transform 260ms var(--xmain-motion-ease), visibility 0s linear 260ms;
    }
    .xmain-menu-open .xmain-mobile-panel, .xmain-mobile-panel.is-open { transition-delay: 0s; }
}

@media (prefers-reduced-motion: no-preference) {
    .xb-more[open] .xb-more-links,
    .xmain-notes-mobile-controls[open] .xmain-notes-mobile-filter-form {
        animation: xmain-surface-enter 220ms var(--xmain-motion-ease);
    }
    .xmp-license-dialog[open] { animation: xmain-dialog-enter 200ms var(--xmain-motion-ease); }
    .xmp-license-dialog[open]::backdrop,
    .xmain-note-lightbox:not([hidden]) { animation: xmain-opacity-enter 180ms ease; }
    .xmain-mobile-panel.is-open .xmain-mobile-panel__list,
    .xmain-mobile-panel.is-open .xb-mobile-secondary { animation: xmain-surface-enter 320ms var(--xmain-motion-ease); }
    @media (hover: hover) and (pointer: fine) {
        .xmain-nav__list a:hover::after { transform: scaleX(1); }
        body.xmain-site :is(.xmain-button, .sp-button, .xmp-button, .xb-header-contact):not(:disabled):hover {
            transform: translateY(-2px);
            box-shadow: 0 5px 14px rgb(32 59 53 / 10%);
        }
        :is(.xb-journal-card, .xb-portal-grid a, .xmain-ebook-card > a):hover { transform: translateY(-3px); }
        :is(.xb-offer, .xb-card, .sp-offer):hover { border-color: #a6beaf; box-shadow: 0 8px 25px rgb(32 59 53 / 5%); }
        .xb-text-link:hover span, .sp-text-link:hover span, .sp-product-lines a:hover .sp-course-meta b,
        .xmain-ebook-card > a:hover .xmain-ebook-card__action > span { transform: translateX(4px); }
        .xb-portal-grid a:hover em { transform: translate(3px, -3px); }
        .xb-footer-columns a:hover { color: #203b35; }
    }
}

@keyframes xmain-surface-enter {
    from { opacity: .65; transform: translateY(6px); }
    to { opacity: 1; transform: translateY(0); }
}
@keyframes xmain-dialog-enter {
    from { opacity: .7; transform: translateY(6px) scale(.985); }
    to { opacity: 1; transform: none; }
}
@keyframes xmain-opacity-enter { from { opacity: .65; } to { opacity: 1; } }

@media (prefers-reduced-motion: reduce) {
    html { scroll-behavior: auto; }
    body.xmain-site *, body.xmain-site *::before, body.xmain-site *::after {
        animation-duration: .001ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: .001ms !important;
        transition-delay: 0ms !important;
        scroll-behavior: auto !important;
    }
    body.xmain-site :is(.xmain-button, .sp-button, .xmp-button, .xb-header-contact, .xmain-wechat-card, .xmp-manuscript-panel button):is(:hover, :active),
    :is(.xb-journal-card, .xb-portal-grid a, .xmain-ebook-card > a):hover { transform: none; }
    .xmain-reveal { transform: none; }
}

@media print {
    .xmain-header { box-shadow: none; }
    body.xmain-site *, body.xmain-site *::before, body.xmain-site *::after { animation: none !important; transition: none !important; }
}