/* ==========================================================================
   CinderTek - Approach page
   Five engineering stages with a sticky stage map and a continuous rail.
   Loaded only by approach.html, after pages.css.
   ========================================================================== */

@property --map-compact {
    syntax: "<number>";
    inherits: true;
    initial-value: 0;
}

:root {
    --stage-map-stuck-height: 6.5rem;
}

/* --------------------------------------------------------------------------
   Stage map
   -------------------------------------------------------------------------- */

.stage-map {
    --node: 11px;
    --map-compact: 0;
    --map-pad-block: calc(1.5rem - var(--map-compact) * 0.375rem);
    --map-link-pad: calc(var(--node) + 1.5rem - var(--map-compact) * 0.375rem);
    --map-name-size: calc(1.125rem - var(--map-compact) * 0.125rem);
    --map-gap: calc(var(--space-6) - var(--map-compact) * var(--space-2));

    position: sticky;
    top: var(--header-height);
    z-index: var(--z-sticky);
    margin-bottom: var(--space-10);
    padding-block: var(--map-pad-block);
    background-color: var(--color-bg);
    border-bottom: var(--border-hairline) solid transparent;
}

.stage-map.is-sticky {
    border-bottom-color: var(--color-border-strong);
}

.stage-map__list {
    position: relative;
    display: grid;
    grid-template-columns: repeat(5, minmax(0, 1fr));
    gap: var(--map-gap);
}

/* The line runs from the first node to a terminal tick at the right edge. */
.stage-map__list::before,
.stage-map__list::after {
    content: "";
    position: absolute;
    background-color: var(--color-border-strong);
}

.stage-map__list::before {
    top: calc(var(--node) / 2);
    left: calc(var(--node) / 2);
    right: 0;
    height: var(--border-hairline);
}

.stage-map__list::after {
    top: 0;
    right: 0;
    width: var(--border-hairline);
    height: var(--node);
}

.stage-item__link {
    position: relative;
    display: grid;
    gap: calc(var(--space-1) + (1 - var(--map-compact)) * var(--space-1));
    padding-top: var(--map-link-pad);
    color: var(--color-text-body);
    transition: color var(--duration-fast) var(--ease-standard);
}

.stage-item__link::before {
    content: "";
    position: absolute;
    top: 0;
    left: 0;
    width: var(--node);
    height: var(--node);
    background-color: var(--color-bg);
    border: var(--border-strong);
    transform: rotate(45deg);
    transition:
        background-color var(--duration-moderate) var(--ease-standard),
        border-color var(--duration-moderate) var(--ease-standard);
}

.stage-item__link::after {
    content: "";
    position: absolute;
    left: 0;
    bottom: -0.3em;
    width: 100%;
    max-width: 6.5ch;
    height: var(--border-hairline);
    background-color: var(--color-accent);
    transform: scaleX(0);
    transform-origin: left;
    transition: transform var(--duration-moderate) var(--ease-out);
}

.stage-item.is-complete .stage-item__link::before {
    background-color: var(--color-border-strong);
}

.stage-item.is-active .stage-item__link {
    color: var(--color-text);
}

.stage-item.is-active .stage-item__link::before {
    background-color: var(--color-accent);
    border-color: var(--color-accent);
}

.stage-item.is-active .stage-item__link::after {
    transform: scaleX(1);
}

@media (hover: hover) {
    .stage-item:not(.is-active) .stage-item__link:hover {
        color: var(--color-text);
    }

    .stage-item:not(.is-active) .stage-item__link:hover::before {
        background-color: var(--color-border-strong);
    }
}

.stage-map__index {
    font-size: var(--fs-xs);
    font-weight: var(--fw-medium);
    line-height: var(--lh-none);
    letter-spacing: var(--ls-wide);
    font-variant-numeric: tabular-nums lining-nums;
    color: var(--color-text-muted);
    transition: color var(--duration-fast) var(--ease-standard);
}

.stage-item.is-active .stage-map__index {
    color: var(--color-link);
}

.stage-map__name {
    font-family: var(--font-display);
    font-size: var(--map-name-size);
    font-weight: var(--fw-semibold);
    line-height: var(--lh-snug);
    letter-spacing: var(--ls-tight);
}

/* --------------------------------------------------------------------------
   Stages - rail column + content, one row per stage
   -------------------------------------------------------------------------- */

.stages {
    --node: 11px;
    --stage-pad: var(--space-16);
    --stage-anchor: calc(var(--stage-pad) + 0.6em);

    position: relative;
}

.stages__progress {
    position: absolute;
    top: var(--stage-anchor);
    bottom: var(--stage-anchor);
    left: calc(var(--node) / 2);
    z-index: 1;
    width: var(--border-hairline);
    background-color: var(--color-accent);
    transform: scaleY(0);
    transform-origin: top center;
    pointer-events: none;
}

.approach-stage {
    display: grid;
    grid-template-columns: repeat(12, minmax(0, 1fr));
    column-gap: var(--grid-gap);
    scroll-margin-top: calc(var(--header-height) + var(--stage-map-stuck-height) + var(--space-4));
}

.approach-stage__rail {
    position: relative;
    font-size: var(--fs-2xl);
    line-height: var(--lh-snug);
}

.approach-stage__rail::before {
    content: "";
    position: absolute;
    top: 0;
    bottom: 0;
    left: calc(var(--node) / 2);
    width: var(--border-hairline);
    background-color: var(--color-border-strong);
    transform: translateX(-50%);
}

.approach-stage:first-child .approach-stage__rail::before {
    top: var(--stage-anchor);
}

.approach-stage:last-child .approach-stage__rail::before {
    bottom: auto;
    height: var(--stage-anchor);
}

.approach-stage__rail::after {
    content: "";
    position: absolute;
    top: var(--stage-anchor);
    left: var(--node);
    right: var(--space-4);
    height: var(--border-hairline);
    background-color: var(--color-border);
    transform: scaleX(0);
    transform-origin: left;
}

.approach-stage.is-inview .approach-stage__rail::after,
.no-js .approach-stage__rail::after {
    transform: scaleX(1);
    transition: transform var(--duration-slower) var(--ease-out);
}

.approach-stage__node {
    position: absolute;
    z-index: 2;
    top: var(--stage-anchor);
    left: 0;
    width: var(--node);
    height: var(--node);
    margin-top: calc(var(--node) / -2);
    background-color: var(--color-bg);
    border: var(--border-strong);
    transform: rotate(45deg);
    transition:
        background-color var(--duration-moderate) var(--ease-standard),
        border-color var(--duration-moderate) var(--ease-standard);
}

.approach-stage.is-complete .approach-stage__node {
    background-color: var(--color-border-strong);
}

.approach-stage.is-active .approach-stage__node {
    background-color: var(--color-accent);
    border-color: var(--color-accent);
}

.approach-stage__content {
    grid-column: 2 / -1;
    display: grid;
    grid-template-columns: repeat(11, minmax(0, 1fr));
    align-items: start;
    gap: var(--space-6) var(--grid-gap);
    padding-block: var(--stage-pad);
    border-top: var(--border-default);
}

.approach-stage:first-child .approach-stage__content {
    border-top: var(--border-strong);
}

.approach-stage:last-child .approach-stage__content {
    border-bottom: var(--border-default);
}

.approach-stage__index,
.approach-stage__title {
    font-family: var(--font-display);
    font-size: var(--fs-2xl);
    font-weight: var(--fw-semibold);
    line-height: var(--lh-snug);
    letter-spacing: var(--ls-tight);
}

.approach-stage__index {
    grid-column: 1 / span 2;
    font-variant-numeric: tabular-nums lining-nums;
    color: var(--color-text-muted);
    transition: color var(--duration-fast) var(--ease-standard);
}

.approach-stage.is-active .approach-stage__index {
    color: var(--color-link);
}

.approach-stage__title {
    grid-column: 3 / span 4;
}

.approach-stage__text {
    grid-column: 7 / -1;
    max-width: var(--measure-narrow);
    padding-top: calc(0.6 * var(--fs-2xl) - 0.75 * var(--fs-lg));
}

/* --------------------------------------------------------------------------
   Responsive
   -------------------------------------------------------------------------- */

@media (max-width: 1023.98px) {
    :root {
        --stage-map-stuck-height: 6.25rem;
    }

    .approach-stage {
        grid-template-columns: var(--space-12) minmax(0, 1fr);
        column-gap: var(--space-4);
    }

    .approach-stage__rail::after {
        right: 0;
    }

    .approach-stage__content {
        grid-column: 2;
        grid-template-columns: auto minmax(0, 1fr);
        gap: var(--space-4) var(--space-6);
    }

    .approach-stage__index,
    .approach-stage__title {
        grid-column: auto;
    }

    .approach-stage__text {
        grid-column: 2;
        padding-top: 0;
    }
}

@media (max-width: 767.98px) {
    :root {
        --stage-map-stuck-height: 5.75rem;
    }

    .stage-map {
        margin-bottom: var(--space-8);
    }

    .stage-map__name {
        font-size: var(--fs-xs);
    }

    .stage-item__link::after {
        max-width: 100%;
    }

    .stages {
        --stage-pad: var(--space-10);
    }

    .approach-stage {
        grid-template-columns: var(--space-8) minmax(0, 1fr);
        column-gap: var(--space-3);
    }

    .approach-stage__content {
        gap: var(--space-4);
    }

    .approach-stage__text {
        grid-column: 1 / -1;
    }
}

@media (prefers-reduced-motion: reduce) {
    .stages__progress {
        transform: none;
    }

    .approach-stage__rail::after {
        transform: none;
    }
}