/*
 * The transitions an action runs between its states — buttons, connected segments, menu items,
 * the FAB menu's trigger, and an extended FAB collapsing to a FAB on scroll.
 *
 * M3 has two spring styles and they are not interchangeable: spatial moves things (position,
 * size, rotation, rounded corners) and overshoots by 9% on the way, effects changes how things
 * look (colour, opacity, elevation) and is critically damped, because a colour must never
 * overshoot — tokens/motion.css says so in the library's own words. An element whose corners and
 * colours both change on a press therefore needs two springs at once, which Tailwind cannot write
 * (`duration-*` and `ease-*` each emit one value); CSS can, by giving `transition-property` a
 * list and matching it position for position.
 *
 * `state-transition-fast` is the press/hover/select transition of a control the finger lands on:
 * shape, size and the place it sits on the fast spatial spring (a `fab` button nudges up when a
 * snackbar arrives under it), colour and elevation on the fast effects spring.
 * `state-transition-default` is the same pair one step slower, for the bigger morph of a FAB
 * turning into a close button.
 *
 * `popover-transition` is the enter and exit of a menu: M3 asks for a transition that ties the
 * list to its trigger, so it scales up from its `transform-origin` on the spatial spring while it
 * fades in on the effects one, and `allow-discrete` keeps `display` and `overlay` alive long
 * enough for the exit to be seen.
 *
 * These are `@utility` declarations, so they compile into Tailwind's utilities layer like any
 * other class: a `transition-*` utility written beside one on the call site will fight it, and
 * whichever Tailwind emits last wins. Pass neither.
 */

@utility state-transition-fast {
    transition-property: border-radius, padding, margin, bottom, background-color, color, box-shadow;
    transition-duration:
        var(--md-sys-motion-spatial-fast-duration), var(--md-sys-motion-spatial-fast-duration),
        var(--md-sys-motion-spatial-fast-duration), var(--md-sys-motion-spatial-fast-duration),
        var(--md-sys-motion-effects-fast-duration), var(--md-sys-motion-effects-fast-duration), var(--md-sys-motion-effects-fast-duration);
    transition-timing-function:
        var(--md-sys-motion-spatial-fast), var(--md-sys-motion-spatial-fast),
        var(--md-sys-motion-spatial-fast), var(--md-sys-motion-spatial-fast),
        var(--md-sys-motion-effects-fast), var(--md-sys-motion-effects-fast), var(--md-sys-motion-effects-fast);
}

@utility state-transition-default {
    transition-property: border-radius, padding, margin, background-color, color, box-shadow;
    transition-duration:
        var(--md-sys-motion-spatial-default-duration), var(--md-sys-motion-spatial-default-duration), var(--md-sys-motion-spatial-default-duration),
        var(--md-sys-motion-effects-default-duration), var(--md-sys-motion-effects-default-duration), var(--md-sys-motion-effects-default-duration);
    transition-timing-function:
        var(--md-sys-motion-spatial-default), var(--md-sys-motion-spatial-default), var(--md-sys-motion-spatial-default),
        var(--md-sys-motion-effects-default), var(--md-sys-motion-effects-default), var(--md-sys-motion-effects-default);
}

@utility popover-transition {
    opacity: 0;
    scale: 0.95;
    transition-property: opacity, scale, display, overlay;
    transition-duration:
        var(--md-sys-motion-effects-fast-duration), var(--md-sys-motion-spatial-fast-duration),
        var(--md-sys-motion-spatial-fast-duration), var(--md-sys-motion-spatial-fast-duration);
    transition-timing-function:
        var(--md-sys-motion-effects-fast), var(--md-sys-motion-spatial-fast), linear, linear;
    transition-behavior: allow-discrete;

    &:popover-open {
        opacity: 1;
        scale: 1;
    }

    @starting-style {
        &:popover-open {
            opacity: 0;
            scale: 0.95;
        }
    }
}

/*
 * A FAB menu's items rise into place as the list opens and sink back as it closes. The entry is
 * `@starting-style` on the item itself; the exit needs the state to be readable while the popover
 * is on its way out, which is what `:not(:popover-open)` is — the popover keeps `display: flex`
 * for the length of its own discrete transition, so the items have somewhere to animate to.
 *
 * Unlayered (a plain rule, not an `@utility`), so it beats the item's own utilities.
 */
[data-fab-menu]:not(:popover-open) > * {
    translate: 0 0.5rem;
    opacity: 0;
}