/* ============================================================================
   SERVICES STACK — Vertical Coverflow scroll showcase
   ============================================================================
   A vertical stack of 21 service cards. As the user scrolls, each card
   passes through the viewport's center "spotlight" — small + tilted on
   entry from below, flat + full-size when centered, then small + tilted
   again on exit to the top. Multiple cards are visible simultaneously
   (each at a different point along its own scroll-driven animation),
   producing a Coverflow-style stacked-depth look.

   Geometry & motion:
   - perspective on the list container creates a shared 3D camera
   - each .sv-stack-item runs `animation-timeline: view()` — its own
     viewport progress drives transform + opacity, off the main thread
   - keyframes interpolate scale + rotateX + translateZ + opacity around
     the centered (50%) sweet spot

   Visual language matches DESIGN-SYSTEM.md:
   - palette: --color-navy section, --color-navy-light card surface,
     hairline borders + Wealthsimple-elegant editorial restraint
   - type: Tiempos heading with -0.6px tracking, theFuture body,
     Courier New eyebrow with --tracking-widest and ▲ zone marker
   - spacing: --space-* tokens; --section-padding for vertical generosity
   - radius: --radius-lg; motion: --ease-out-expo + --duration-* tokens
   - architectural drawing-sheet motif: faint grid bg + corner L-brackets
   ============================================================================ */

.sv-stack-section {
    /* Two-tone palette — cream section + near-black cards. Matches the
       site's existing cream surface (#F5F3EF used in .sv-grid-section) so
       the section flows into the service cards below. Cards land in
       --color-black (#32302F) for strong B&W contrast; no red accents. */
    --sv-stack-bg: #F5F3EF;                       /* cream section */
    --sv-stack-card: var(--color-black);          /* near-black card */
    --sv-stack-card-hover: #4A4845;               /* lifted on hover */
    --sv-stack-rule: rgba(50, 48, 47, 0.18);      /* black hairline */
    --sv-stack-card-rule: rgba(255, 255, 255, 0.10);
    --sv-stack-card-rule-hover: rgba(255, 255, 255, 0.22);
    --sv-stack-card-text: var(--color-text-on-dark);     /* icon/title color */
    --sv-stack-card-dot: rgba(255, 255, 255, 0.55);      /* splotch dot color */

    position: relative;
    isolation: isolate;   /* new stacking context so .__bg can sit at z-index: -1 */
    padding: var(--section-padding) 0;
    background: var(--sv-stack-bg);
    color: var(--color-text-primary);
    overflow: clip;
}

/* Architectural drawing-sheet grid lives on a parallax layer behind the
   content. Extends 25% beyond the section's top and bottom so the layer can
   translate without revealing blank edges. Blurred for a soft, atmospheric
   feel — strong parallax movement is driven by animation-timeline: view(). */
.sv-stack-section__bg {
    position: absolute;
    inset: -25% 0;
    z-index: -1;
    pointer-events: none;
    background-image:
        linear-gradient(rgba(50, 48, 47, 0.07) 1px, transparent 1px),
        linear-gradient(90deg, rgba(50, 48, 47, 0.07) 1px, transparent 1px),
        linear-gradient(rgba(50, 48, 47, 0.03) 1px, transparent 1px),
        linear-gradient(90deg, rgba(50, 48, 47, 0.03) 1px, transparent 1px);
    background-size: 80px 80px, 80px 80px, 20px 20px, 20px 20px;
    filter: blur(3px);
    will-change: transform;
}

@supports (animation-timeline: view()) {
    .sv-stack-section__bg {
        animation: sv-stack-bg-parallax linear;
        animation-timeline: view();
        animation-range: cover 0% cover 100%;
        animation-fill-mode: both;
    }
    @keyframes sv-stack-bg-parallax {
        from { transform: translate3d(0, 18%, 0); }
        to   { transform: translate3d(0, -18%, 0); }
    }
}

@media (prefers-reduced-motion: reduce) {
    .sv-stack-section__bg { animation: none !important; transform: none !important; }
}

/* Corner L-brackets — architectural-drawing motif, framing the section. */
.sv-stack-section::before,
.sv-stack-section::after {
    content: '';
    position: absolute;
    width: var(--space-10);
    height: var(--space-10);
    border-color: rgba(50, 48, 47, 0.32);
    border-style: solid;
    pointer-events: none;
    z-index: 1;
}
.sv-stack-section::before {
    top: var(--space-8); left: var(--space-8);
    border-width: 1px 0 0 1px;
}
.sv-stack-section::after {
    bottom: var(--space-8); right: var(--space-8);
    border-width: 0 1px 1px 0;
}

/* ----- Stacked layout: centered copy on top, card grid below ----------- */
.sv-stack-grid {
    max-width: var(--container-max);
    margin: 0 auto;
    padding: 0 var(--container-padding);
    display: flex;
    flex-direction: column;
    align-items: center;
    row-gap: var(--space-10);
}

/* ----- Top: editorial copy, centered above the stack --------------------- */
.sv-stack-side {
    display: flex;
    flex-direction: column;
    align-items: center;
    text-align: center;
    gap: var(--space-6);
    max-width: var(--text-max-width);
    z-index: 2;
}

.sv-stack-side__eyebrow {
    margin: 0;
    font-family: "Courier New", monospace;
    font-size: var(--text-xs);
    font-weight: var(--font-semibold);
    letter-spacing: var(--tracking-widest);
    text-transform: uppercase;
    color: var(--color-text-primary);
    opacity: 0.55;
}
.sv-stack-side__eyebrow::before {
    content: '▲';
    margin-right: var(--space-2);
    color: var(--color-text-primary);
    opacity: 0.85;
}

.sv-stack-side__headline {
    margin: 0;
    font-family: var(--font-heading);
    font-size: var(--text-section);
    font-weight: var(--font-semibold);
    line-height: var(--leading-tight);
    letter-spacing: -0.6px;
    color: var(--color-text-primary);
}

.sv-stack-side__lead {
    margin: 0;
    max-width: 52ch;
    font-family: var(--font-body);
    font-size: var(--text-base);
    font-weight: var(--font-regular);
    line-height: var(--leading-normal);
    letter-spacing: 0.1px;
    color: var(--color-text-primary);
    opacity: 0.65;
}

.sv-stack-side__count {
    margin-top: var(--space-4);
    padding-top: var(--space-6);
    border-top: 1px solid var(--sv-stack-rule);
    font-family: "Courier New", monospace;
    font-size: var(--text-xs);
    font-weight: var(--font-semibold);
    letter-spacing: var(--tracking-widest);
    text-transform: uppercase;
    color: var(--color-text-on-dark);
    opacity: 0.7;
}

/* ----- The grouped card grid -------------------------------------------- */
/* Vertical stack of three category blocks. Each block lays its label rail
   to the LEFT and its card grid to the RIGHT — header doesn't consume any
   vertical space of its own. */
.sv-stack-list {
    list-style: none;
    margin: 0 auto;
    padding: var(--space-8) 0 var(--space-16);
    width: 100%;
    display: flex;
    flex-direction: column;
    gap: clamp(20px, 2vw, 36px);
}

/* ----- Per-group card theming -------------------------------------------
   Each category gets its own card surface color, all drawn from the brand
   palette (black + red family). Cards inherit these via var(--sv-stack-card),
   so no other rules need to change. */
.sv-stack-group[data-group="approach"] {
    --sv-stack-card: var(--color-black);        /* #32302F */
    --sv-stack-card-hover: #4A4845;
}
.sv-stack-group[data-group="expertise"] {
    --sv-stack-card: var(--color-gold);         /* #C0392B brand red */
    --sv-stack-card-hover: var(--color-gold-light); /* #D94F3F */
}
.sv-stack-group[data-group="capabilities"] {
    --sv-stack-card: var(--color-white);             /* #FCFCFC */
    --sv-stack-card-hover: #EDE9E2;                  /* warm tone darker than card */
    --sv-stack-card-rule: rgba(50, 48, 47, 0.12);    /* dark hairline border */
    --sv-stack-card-rule-hover: rgba(50, 48, 47, 0.22);
    --sv-stack-card-text: var(--color-text-primary); /* dark text/icons */
    --sv-stack-card-dot: rgba(50, 48, 47, 0.42);     /* dark splotch dots */
}

/* ----- Group block: label rail (left) + card grid (right) ---------------
   L-brackets at all four corners, painted as background gradients. */
.sv-stack-group {
    --sv-group-bracket: rgba(50, 48, 47, 0.32);
    --sv-group-bracket-size: 18px;
    position: relative;
    display: grid;
    grid-template-columns: minmax(160px, 220px) minmax(0, 1fr);
    column-gap: clamp(20px, 2.4vw, 40px);
    align-items: start;
    padding: clamp(18px, 1.8vw, 28px) clamp(16px, 1.8vw, 28px);
    background-image:
        linear-gradient(to right,  var(--sv-group-bracket), var(--sv-group-bracket)),
        linear-gradient(to bottom, var(--sv-group-bracket), var(--sv-group-bracket)),
        linear-gradient(to left,   var(--sv-group-bracket), var(--sv-group-bracket)),
        linear-gradient(to bottom, var(--sv-group-bracket), var(--sv-group-bracket)),
        linear-gradient(to right,  var(--sv-group-bracket), var(--sv-group-bracket)),
        linear-gradient(to top,    var(--sv-group-bracket), var(--sv-group-bracket)),
        linear-gradient(to left,   var(--sv-group-bracket), var(--sv-group-bracket)),
        linear-gradient(to top,    var(--sv-group-bracket), var(--sv-group-bracket));
    background-size:
        var(--sv-group-bracket-size) 1px, 1px var(--sv-group-bracket-size),
        var(--sv-group-bracket-size) 1px, 1px var(--sv-group-bracket-size),
        var(--sv-group-bracket-size) 1px, 1px var(--sv-group-bracket-size),
        var(--sv-group-bracket-size) 1px, 1px var(--sv-group-bracket-size);
    background-position:
        top left,     top left,
        top right,    top right,
        bottom left,  bottom left,
        bottom right, bottom right;
    background-repeat: no-repeat;
}

/* Label rail — left column. Just the single-word category title. */
.sv-stack-group__head {
    min-width: 0;
    padding-right: var(--space-4);
    border-right: 1px solid var(--sv-stack-rule);
}

.sv-stack-group__title {
    margin: 0;
    font-family: var(--font-heading);
    font-size: clamp(1.5rem, 2.2vw, 2rem);
    font-weight: var(--font-semibold);
    line-height: var(--leading-tight);
    letter-spacing: -0.4px;
    color: var(--color-text-primary);
}

/* The card sub-grid — right column. */
.sv-stack-group__cards {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
    gap: var(--space-8);
}

/* The card. Icon is the centerpiece, title sits directly under it. */
.sv-stack-item {
    position: relative;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    text-align: center;
    gap: var(--space-3);
    padding: var(--space-8) var(--space-6);
    min-height: 220px;
    background: var(--sv-stack-card);
    border: 1px solid var(--sv-stack-card-rule);
    border-radius: var(--radius-lg);
    overflow: hidden;
    color: var(--sv-stack-card-text);
    text-decoration: none;
    cursor: pointer;
    transition: background-color var(--duration-base) var(--ease-out-expo),
                border-color var(--duration-base) var(--ease-out-expo),
                transform var(--duration-base) var(--ease-out-expo);
}

/* Dotted-splotch overlay — a fine dot pattern masked to a couple of soft
   splotch zones so it appears sparingly across the card, with a touch of
   blur for atmosphere. Sits beneath the card content via z-index. */
.sv-stack-item::before {
    content: '';
    position: absolute;
    inset: 0;
    pointer-events: none;
    background-image: radial-gradient(circle, var(--sv-stack-card-dot) 1px, transparent 1.6px);
    background-size: 14px 14px;
    -webkit-mask-image:
        radial-gradient(ellipse 55% 45% at 18% 22%, rgba(0, 0, 0, 0.9), transparent 70%),
        radial-gradient(ellipse 45% 40% at 82% 78%, rgba(0, 0, 0, 0.7), transparent 70%);
    mask-image:
        radial-gradient(ellipse 55% 45% at 18% 22%, rgba(0, 0, 0, 0.9), transparent 70%),
        radial-gradient(ellipse 45% 40% at 82% 78%, rgba(0, 0, 0, 0.7), transparent 70%);
    -webkit-mask-composite: source-over;
    mask-composite: add;
    filter: blur(0.6px);
    opacity: 0.7;
    z-index: 0;
}

/* Card content must paint above the splotch overlay. */
.sv-stack-item__body {
    position: relative;
    z-index: 1;
}
.sv-stack-item:hover,
.sv-stack-item:focus-visible {
    background: var(--sv-stack-card-hover);
    border-color: var(--sv-stack-card-rule-hover);
    transform: translateY(-2px);
    outline: none;
}

/* Body wraps the icon + text vertically inside the card. */
.sv-stack-item__body {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--space-2);
    min-width: 0;
}

.sv-stack-item__icon {
    font-size: clamp(3.25rem, 5vw, 4.5rem);
    color: var(--sv-stack-card-text);
    line-height: 1;
    transition: transform var(--duration-base) var(--ease-out-expo);
}
.sv-stack-item:hover .sv-stack-item__icon,
.sv-stack-item:focus-visible .sv-stack-item__icon {
    transform: scale(1.06);
}

.sv-stack-item__title {
    margin: 0;
    font-family: var(--font-heading);
    font-size: var(--text-xl);
    font-weight: var(--font-semibold);
    line-height: var(--leading-tight);
    letter-spacing: -0.3px;
    color: var(--sv-stack-card-text);
}


/* ----- Wide-screen bleed --------------------------------------------------
   On large screens we leave the left rail aligned with the page's normal
   container, and let the cards extend toward the right viewport edge — the
   empty space outside the container becomes part of the card grid. Cards
   are locked to exactly 3 columns at this breakpoint. */
@media (min-width: 1280px) {
    .sv-stack-grid {
        max-width: none;
        padding-left: max(var(--container-padding),
                          calc((100vw - var(--container-max)) / 2 + var(--container-padding)));
        padding-right: clamp(28px, 3vw, 64px);
    }
    /* Keep the section headline visually aligned with the original container —
       align it to the start (left rail position) instead of full-row center. */
    .sv-stack-side {
        align-self: flex-start;
        text-align: left;
        align-items: flex-start;
        max-width: 64ch;
    }
    .sv-stack-group__cards {
        grid-template-columns: repeat(3, minmax(0, 1fr));
    }
    .sv-stack-item { min-height: 260px; padding: var(--space-10) var(--space-7); }
    .sv-stack-item__icon { font-size: 5rem; }
}

/* ----- Responsive --------------------------------------------------------- */
@media (max-width: 1024px) {
    .sv-stack-side { max-width: 100%; }
    .sv-stack-list { padding: var(--space-6) 0 var(--space-12); }
    .sv-stack-group {
        grid-template-columns: minmax(140px, 180px) minmax(0, 1fr);
        column-gap: var(--space-5);
    }
    .sv-stack-group__cards {
        grid-template-columns: repeat(auto-fill, minmax(180px, 1fr));
    }
    .sv-stack-item { min-height: 140px; padding: var(--space-4); }
}

/* Below 720px the side-rail is too cramped — collapse to header-on-top. */
@media (max-width: 720px) {
    .sv-stack-group {
        grid-template-columns: 1fr;
        row-gap: var(--space-4);
    }
    .sv-stack-group__head {
        border-right: none;
        padding-right: 0;
        padding-bottom: var(--space-3);
        border-bottom: 1px solid var(--sv-stack-rule);
    }
    .sv-stack-group__cards {
        grid-template-columns: repeat(2, minmax(0, 1fr));
        gap: var(--space-3);
    }
    .sv-stack-item { min-height: 130px; padding: var(--space-3); }
    .sv-stack-item__icon { font-size: 2.25rem; }
    .sv-stack-item__title { font-size: var(--text-sm); }
}

/* ----- Reduced motion ----------------------------------------------------- */
@media (prefers-reduced-motion: reduce) {
    .sv-stack-item,
    .sv-stack-item__icon {
        transition: none !important;
        transform: none !important;
    }
}