/* SolidWorks Robotic Arm — case study */

.arm-story {
    --accent: #c70039;
    --ink: #0a0a0a;
    --mist: rgba(245, 245, 245, .08);
    --steel: #9aa3ad;
    background:
        radial-gradient(900px 520px at 10% 8%, color-mix(in srgb, var(--accent) 9%, transparent), transparent 58%),
        radial-gradient(700px 420px at 92% 24%, rgba(150, 170, 190, .05), transparent 55%),
        #101010;
}

.arm-main.case-study {
    max-width: 1180px;
    margin: 0 auto;
    padding: 110px 24px 80px;
    position: relative;
    z-index: 1;
    overflow-x: hidden;
}

.arm-story #case-chrome-top { position: relative; z-index: 70; }

.arm-dock {
    position: fixed;
    right: 0;
    top: 50%;
    transform: translateY(-50%);
    z-index: 90;
    display: flex;
    flex-direction: column;
    align-items: flex-end;
    gap: 18px;
    pointer-events: none;
}

.arm-dock > * { pointer-events: auto; }

.arm-story .color-changer {
    position: relative;
    right: -150px;
    top: auto;
    z-index: 2;
    transition: right .4s ease;
}

.arm-story .color-changer-active { right: 0; }

.arm-rail {
    position: relative;
    right: 16px;
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.arm-rail a {
    display: grid;
    grid-template-columns: 26px 1fr;
    align-items: center;
    gap: 8px;
    text-decoration: none;
    color: rgba(245, 245, 245, .4);
    font-family: poppins;
    font-size: 10px;
    letter-spacing: 1.2px;
    text-transform: uppercase;
    transition: color .3s ease;
}

.arm-rail a i {
    width: 26px;
    height: 26px;
    border: 1px solid rgba(245, 245, 245, .18);
    border-radius: 50%;
    display: grid;
    place-items: center;
    font-style: normal;
    font-size: 9px;
}

.arm-rail a span {
    opacity: 0;
    transform: translateX(6px);
    transition: opacity .25s ease, transform .25s ease;
    white-space: nowrap;
}

.arm-rail:hover a span,
.arm-rail a.is-active span {
    opacity: 1;
    transform: translateX(0);
}

.arm-rail a.is-active,
.arm-rail a:hover { color: whitesmoke; }

.arm-rail a.is-active i {
    border-color: var(--accent);
    color: var(--accent);
    box-shadow: 0 0 0 3px color-mix(in srgb, var(--accent) 22%, transparent);
}

/* ---- chapters ---- */

.arm-story .chapter {
    position: relative;
    padding: 72px 0 40px;
    max-width: none;
    margin: 0;
}

.arm-story .chapter-index {
    position: static;
    display: block;
    left: auto;
    top: auto;
    font-family: poppins;
    font-size: clamp(56px, 9vw, 96px);
    font-weight: 700;
    line-height: .9;
    letter-spacing: -4px;
    color: rgba(245, 245, 245, .14);
    pointer-events: none;
    margin: 0 0 8px;
}

.arm-story .chapter-head { margin: 0 0 28px; max-width: 720px; }

.arm-story .season-kicker {
    font-family: poppins;
    font-size: 12px;
    letter-spacing: 1.6px;
    text-transform: uppercase;
    color: var(--accent);
    margin: 0 0 10px;
}

.arm-story .chapter-head h2 {
    font-family: poppins;
    font-size: clamp(28px, 4vw, 42px);
    line-height: 1.15;
    letter-spacing: -0.5px;
    margin: 0;
    color: whitesmoke;
}

.arm-story .chapter-prose,
.arm-story .split-copy {
    max-width: 62ch;
}

.arm-story #topology .chapter-prose,
.arm-story #conclusion .chapter-prose {
    max-width: none;
}

.arm-story .chapter-prose p,
.arm-story .split-copy p {
    font-family: poppins;
    font-size: 15px;
    line-height: 1.75;
    opacity: .88;
    margin: 0 0 14px;
}

.arm-story .chapter-prose .lead,
.arm-story .split-copy .lead {
    font-size: clamp(17px, 1.5vw, 20px);
    line-height: 1.7;
}

.arm-story .beat {
    opacity: .95 !important;
    margin: 18px 0;
}

.arm-story .chapter-prose strong,
.arm-story .split-copy strong {
    color: whitesmoke;
    font-weight: 600;
}

.arm-story .reveal {
    opacity: 0;
    transform: translateY(18px);
    transition: opacity .7s ease, transform .7s ease;
}

.arm-story .reveal.is-in {
    opacity: 1;
    transform: none;
}

@media (prefers-reduced-motion: reduce) {
    .arm-story .reveal { opacity: 1; transform: none; transition: none; }
}

/* ---- hero (side-by-side case-hero) ---- */

.arm-story .case-hero {
    margin-bottom: 24px;
}

.arm-story .case-hero-visual video {
    pointer-events: none;
}

.arm-story .case-pager {
    max-width: none;
    margin: 40px 0 0;
    padding: 0;
}

/* ---- layouts ---- */

.arm-split {
    display: grid;
    grid-template-columns: 1fr 1.15fr;
    gap: 36px;
    align-items: start;
}

.arm-media-frame {
    margin: 0;
    border: 1px solid var(--mist);
    background: #f4f4f4;
    overflow: hidden;
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 280px;
}

.arm-media-frame img,
.arm-media-frame video {
    width: 100%;
    height: auto;
    max-height: min(520px, 62vh);
    object-fit: contain;
    display: block;
    background: #f4f4f4;
}

.arm-explode-frame {
    position: relative;
    min-height: 0;
    background: #f4f4f4;
}

.arm-explode-frame img {
    max-height: min(640px, 72vh);
    width: 100%;
    height: auto;
    object-fit: contain;
    background: #f4f4f4;
}

.arm-fs-btn {
    position: absolute;
    right: 10px;
    bottom: 10px;
    z-index: 2;
    border: 1px solid rgba(10, 10, 10, .18);
    background: rgba(10, 10, 10, .78);
    color: whitesmoke;
    font-family: poppins;
    font-size: 11px;
    letter-spacing: .8px;
    text-transform: uppercase;
    padding: 8px 12px;
    cursor: pointer;
    transition: background .2s ease, border-color .2s ease;
}

.arm-fs-btn:hover {
    background: rgba(10, 10, 10, .92);
    border-color: color-mix(in srgb, var(--accent) 55%, transparent);
}

.arm-media-stack {
    display: grid;
    gap: 12px;
}

.arm-media-stack .arm-spec-row {
    margin: 4px 0 0;
}

/* fullscreen lightbox */
.arm-lightbox {
    position: fixed;
    inset: 0;
    z-index: 200;
    display: grid;
    place-items: center;
    padding: 28px;
    background: rgba(5, 5, 5, .94);
}

.arm-lightbox[hidden] { display: none !important; }

.arm-lightbox figure {
    margin: 0;
    width: min(1400px, 100%);
    max-height: 100%;
    display: grid;
    gap: 12px;
    justify-items: center;
}

.arm-lightbox img,
.arm-lightbox video {
    max-width: 100%;
    max-height: calc(100vh - 96px);
    width: auto;
    height: auto;
    object-fit: contain;
    background: #0a0a0a;
    display: block;
}

.arm-lightbox img[hidden],
.arm-lightbox video[hidden] {
    display: none !important;
}

.arm-lightbox figcaption {
    font-family: poppins;
    font-size: 13px;
    opacity: .65;
    text-align: center;
}

.arm-lightbox-close {
    position: absolute;
    top: 18px;
    right: 18px;
    width: 44px;
    height: 44px;
    border: 1px solid rgba(245, 245, 245, .2);
    background: rgba(255, 255, 255, .04);
    color: whitesmoke;
    font-size: 28px;
    line-height: 1;
    cursor: pointer;
}

.arm-lightbox-close:hover {
    border-color: var(--accent);
    color: var(--accent);
}

.arm-lightbox-nav {
    position: absolute;
    top: 50%;
    transform: translateY(-50%);
    width: 48px;
    height: 48px;
    border: 1px solid rgba(245, 245, 245, .22);
    background: rgba(255, 255, 255, .06);
    color: whitesmoke;
    font-size: 30px;
    line-height: 1;
    cursor: pointer;
    z-index: 2;
}

.arm-lightbox-nav:hover {
    border-color: var(--accent);
    color: var(--accent);
}

.arm-lightbox-prev { left: 18px; }
.arm-lightbox-next { right: 18px; }

.arm-lightbox-nav[hidden] { display: none !important; }

.arm-lightbox-count {
    margin: 0;
    font-family: poppins;
    font-size: 11px;
    letter-spacing: 1.4px;
    text-transform: uppercase;
    opacity: .45;
}

.arm-lightbox-count[hidden] { display: none !important; }

body.arm-fs-open { overflow: hidden; }

.arm-spec-row {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 12px;
    margin: 22px 0 8px;
}

.arm-spec {
    border: 1px solid var(--mist);
    padding: 14px 16px;
    background: rgba(255, 255, 255, .02);
}

.arm-spec small {
    display: block;
    font-family: poppins;
    font-size: 10px;
    letter-spacing: 1.2px;
    text-transform: uppercase;
    color: var(--accent);
    margin-bottom: 6px;
}

.arm-spec strong {
    font-family: poppins;
    font-size: 14px;
    font-weight: 500;
    color: whitesmoke;
}

/* drawings */

.arm-subhead {
    font-family: poppins;
    font-size: clamp(20px, 2.4vw, 26px);
    font-weight: 600;
    letter-spacing: -.3px;
    color: whitesmoke;
    margin: 36px 0 16px;
}

.arm-draw-carousel {
    border: 1px solid var(--mist);
    background: #0b0b0b;
    padding: 14px;
}

.arm-draw-stage {
    position: relative;
    border: 1px solid var(--mist);
    background: #f4f4f4;
    overflow: hidden;
    height: min(520px, 62vh);
    min-height: 300px;
}

.arm-draw-track {
    position: absolute;
    inset: 0;
}

.arm-draw-slide {
    position: absolute;
    inset: 0;
    margin: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 16px;
    box-sizing: border-box;
    opacity: 0;
    transform: translateX(24px);
    transition: opacity .45s ease, transform .55s cubic-bezier(.22, 1, .36, 1);
    pointer-events: none;
}

.arm-draw-slide.is-active {
    opacity: 1;
    transform: translateX(0);
    pointer-events: auto;
    z-index: 2;
}

.arm-draw-slide.is-exit {
    opacity: 0;
    transform: translateX(-18px);
    z-index: 1;
}

.arm-draw-slide img,
.arm-draw-slide video {
    width: auto;
    height: auto;
    max-width: 100%;
    max-height: 100%;
    object-fit: contain;
    display: block;
    background: #f4f4f4;
}

.arm-draw-slide video {
    background: #0a0a0a;
}

.arm-draw-stage .arm-fs-btn {
    z-index: 3;
}

.arm-draw-ui {
    display: grid;
    grid-template-columns: auto 1fr auto;
    grid-template-areas:
        "prev thumbs next"
        "label label label"
        "count count count";
    gap: 10px 8px;
    align-items: center;
    margin-top: 12px;
}

.arm-draw-nav {
    width: 34px;
    height: 34px;
    border: 1px solid rgba(245, 245, 245, .18);
    background: rgba(255, 255, 255, .03);
    color: whitesmoke;
    font-size: 22px;
    line-height: 1;
    cursor: pointer;
}

.arm-draw-nav:hover {
    border-color: color-mix(in srgb, var(--accent) 60%, transparent);
    color: var(--accent);
}

.arm-draw-nav[data-draw-prev],
.arm-draw-nav[data-media-prev] { grid-area: prev; }
.arm-draw-nav[data-draw-next],
.arm-draw-nav[data-media-next] { grid-area: next; }

.arm-draw-thumbs {
    grid-area: thumbs;
    display: flex;
    gap: 6px;
    overflow-x: auto;
    scrollbar-width: none;
    padding: 2px 0;
}

.arm-draw-thumbs::-webkit-scrollbar { display: none; }

.arm-draw-thumbs button {
    flex: 0 0 auto;
    width: 52px;
    height: 36px;
    padding: 0;
    border: 1px solid rgba(245, 245, 245, .14);
    background: #111;
    cursor: pointer;
    opacity: .55;
    overflow: hidden;
    display: flex;
    align-items: center;
    justify-content: center;
}

.arm-draw-thumbs button.is-on {
    opacity: 1;
    border-color: var(--accent);
}

.arm-draw-thumbs img {
    width: auto;
    height: auto;
    max-width: 100%;
    max-height: 100%;
    object-fit: contain;
    display: block;
    background: #f4f4f4;
    pointer-events: none;
}

.arm-draw-count {
    grid-area: count;
    margin: 0;
    font-family: poppins;
    font-size: 11px;
    letter-spacing: 1.4px;
    text-transform: uppercase;
    opacity: .45;
    text-align: center;
}

.arm-draw-label {
    grid-area: label;
    margin: 0;
    font-family: poppins;
    font-size: 14px;
    color: rgba(245, 245, 245, .8);
    text-align: center;
}

/* motion block */

.arm-motion-layout {
    display: grid;
    grid-template-columns: minmax(260px, 0.9fr) minmax(0, 1.4fr);
    gap: 40px;
    align-items: start;
    margin-top: 8px;
}

.arm-motion-layout .chapter-prose {
    max-width: none;
    margin: 0;
}

.arm-motion-carousel {
    min-width: 0;
}

.arm-motion-stage {
    height: min(680px, 74vh);
    min-height: 420px;
    background: #0a0a0a;
}

.arm-motion {
    display: grid;
    grid-template-columns: 1.1fr .9fr;
    gap: 28px;
    margin-top: 28px;
    align-items: start;
}

.arm-video {
    margin: 0;
    border: 1px solid var(--mist);
    background: #0a0a0a;
    overflow: hidden;
}

.arm-video video {
    width: 100%;
    max-height: min(420px, 56vh);
    object-fit: contain;
    display: block;
    background: #0a0a0a;
}

.arm-caption {
    font-family: poppins;
    font-size: 12px;
    opacity: .5;
    margin: 8px 0 0;
}

/* ---- topology highlight ---- */

.topo-board {
    margin-top: 8px;
    border: 1px solid var(--mist);
    background:
        linear-gradient(180deg, rgba(255,255,255,.02), transparent 40%),
        #0b0b0b;
    padding: clamp(22px, 3vw, 36px);
}

.topo-kicker {
    font-family: poppins;
    font-size: 11px;
    letter-spacing: 1.6px;
    text-transform: uppercase;
    color: var(--accent);
    margin: 0 0 18px;
}

.topo-metrics {
    display: grid;
    grid-template-columns: 1.1fr 1fr 1fr;
    gap: 18px;
    align-items: end;
    margin-bottom: 22px;
}

.topo-metric small {
    display: block;
    font-family: poppins;
    font-size: 11px;
    letter-spacing: 1px;
    text-transform: uppercase;
    opacity: .5;
    margin-bottom: 8px;
}

.topo-metric strong {
    font-family: poppins;
    font-size: clamp(28px, 4vw, 44px);
    font-weight: 600;
    letter-spacing: -1px;
    color: whitesmoke;
    line-height: 1;
}

.topo-metric.topo-hero strong {
    font-size: clamp(48px, 8vw, 84px);
    color: var(--accent);
}

.topo-metric.topo-hero em {
    display: block;
    font-style: normal;
    font-family: poppins;
    font-size: 12px;
    letter-spacing: 1.4px;
    text-transform: uppercase;
    color: whitesmoke;
    opacity: .7;
    margin-top: 10px;
}

.topo-bar {
    position: relative;
    height: 10px;
    background: rgba(245, 245, 245, .08);
    overflow: hidden;
    margin: 8px 0 10px;
}

.topo-bar > span {
    display: block;
    height: 100%;
    width: 56.5%;
    background: var(--accent);
}

.topo-bar-labels {
    display: flex;
    justify-content: space-between;
    font-family: poppins;
    font-size: 12px;
    opacity: .55;
}

.topo-note {
    font-family: poppins;
    font-size: 12px;
    opacity: .45;
    margin: 14px 0 0;
    max-width: 62ch;
}

.topo-compare {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 12px;
    margin-top: 28px;
}

.topo-compare figure {
    margin: 0;
    border: 1px solid var(--mist);
    background: #f3f3f3;
    overflow: hidden;
}

.topo-compare img {
    width: 100%;
    aspect-ratio: 1;
    object-fit: contain;
    display: block;
    background: #f3f3f3;
}

.topo-compare figcaption {
    font-family: poppins;
    font-size: 12px;
    padding: 10px 12px 12px;
    background: #0c0c0c;
    color: rgba(245, 245, 245, .7);
}

.topo-gallery {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 10px;
    margin-top: 18px;
}

.topo-gallery figure {
    margin: 0;
    border: 1px solid var(--mist);
    background: #0a0a0a;
    overflow: hidden;
}

.topo-gallery img {
    width: 100%;
    aspect-ratio: 16 / 11;
    object-fit: contain;
    display: block;
    background: #111;
}

.topo-gallery figcaption {
    font-family: poppins;
    font-size: 11px;
    padding: 8px 10px 10px;
    opacity: .55;
}

@media (max-width: 980px) {
    .arm-rail { display: none; }
    .arm-dock { top: 120px; transform: none; }
    .arm-main.case-study { padding: 96px 18px 64px; }
    .arm-split,
    .arm-motion,
    .arm-motion-layout,
    .topo-metrics,
    .topo-compare { grid-template-columns: 1fr; }
    .arm-spec-row,
    .topo-gallery { grid-template-columns: 1fr 1fr; }
    .arm-motion-stage { height: min(520px, 62vh); }
}

@media (max-width: 640px) {
    .arm-spec-row { grid-template-columns: 1fr; }
    .arm-draw-stage { height: min(380px, 55vh); }
    .arm-motion-stage { height: min(360px, 52vh); min-height: 280px; }
}

@media (prefers-reduced-motion: reduce) {
    .arm-draw-slide {
        transition: opacity .2s ease;
        transform: none;
    }
}