/* =========================================================
   BSK ABOUT — visual prototype
   Scoped styles: .bsk-about-*
   No external libraries.
   ========================================================= */

:root {
    --bsk-about-blue: #0758b8;
    --bsk-about-blue-deep: #07345f;
    --bsk-about-navy: #062b4e;
    --bsk-about-text: #172236;
    --bsk-about-muted: #65748a;
    --bsk-about-line: #dce4ed;
    --bsk-about-soft: #f4f7fa;
    --bsk-about-white: #fff;
    --bsk-about-radius: 4px;
    --bsk-about-container: 1320px;
}

.bsk-about,
.bsk-about *,
.bsk-about *::before,
.bsk-about *::after {
    box-sizing: border-box;
}

.bsk-about {
    width: 100%;
    overflow: clip;
    color: var(--bsk-about-text);
    background: #fff;
    font-family: inherit;
    line-height: 1.55;
}

.bsk-about img,
.bsk-about video {
    display: block;
    max-width: 100%;
}

.bsk-about a {
    text-decoration: none;
}

.bsk-about-container {
    width: min(calc(100% - 48px), var(--bsk-about-container));
    margin-inline: auto;
}

.bsk-about-section {
    padding: 86px 0;
}

.bsk-about-kicker {
    margin-bottom: 14px;
    color: var(--bsk-about-blue);
    font-size: 12px;
    font-weight: 700;
    letter-spacing: .09em;
    text-transform: uppercase;
}

.bsk-about-kicker--light {
    color: #a9cef6;
}

.bsk-about-title {
    max-width: 780px;
    margin: 0 0 22px;
    color: var(--bsk-about-text);
    font-size: clamp(30px, 3vw, 48px);
    line-height: 1.08;
    letter-spacing: -.025em;
}

.bsk-about-heading {
    margin-bottom: 38px;
}

.bsk-about-heading p {
    max-width: 700px;
    margin: 0;
    color: var(--bsk-about-muted);
}

.bsk-about-btn {
    display: inline-flex;
    min-height: 48px;
    align-items: center;
    justify-content: center;
    padding: 0 24px;
    border: 1px solid transparent;
    border-radius: 3px;
    font-size: 14px;
    font-weight: 700;
    line-height: 1;
    transition: transform .2s ease, background-color .2s ease, color .2s ease, border-color .2s ease;
}

.bsk-about-btn:hover {
    transform: translateY(-2px);
}

.bsk-about-btn--primary {
    color: #fff;
    background: var(--bsk-about-blue);
}

.bsk-about-btn--secondary {
    color: var(--bsk-about-blue);
    background: #fff;
    border-color: #8bb1db;
}

.bsk-about-btn--light {
    color: var(--bsk-about-navy);
    background: #fff;
}

.bsk-about-btn--ghost {
    color: #fff;
    border-color: rgba(255,255,255,.55);
    background: transparent;
}

.bsk-about-actions {
    display: flex;
    flex-wrap: wrap;
    gap: 12px;
}

/* HERO */
.bsk-about-hero {
    padding: 46px 0 64px;
    background:
        radial-gradient(circle at 75% 0%, rgba(8,88,184,.06), transparent 34%),
        #fff;
}

.bsk-about-hero__grid {
    display: grid;
    grid-template-columns: minmax(0, .92fr) minmax(420px, 1.08fr);
    gap: clamp(42px, 6vw, 90px);
    align-items: center;
}

.bsk-about-hero__title {
    margin: 0 0 22px;
    font-size: clamp(46px, 5vw, 72px);
    line-height: .98;
    letter-spacing: -.04em;
}

.bsk-about-hero__lead {
    max-width: 620px;
    margin: 0 0 16px;
    font-size: 20px;
    line-height: 1.45;
}

.bsk-about-hero__text {
    max-width: 650px;
    margin: 0;
    color: var(--bsk-about-muted);
}

.bsk-about-facts {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 18px;
    margin: 34px 0 32px;
}

.bsk-about-fact {
    min-width: 0;
}

.bsk-about-fact__icon {
    display: flex;
    width: 48px;
    height: 48px;
    align-items: center;
    justify-content: center;
    margin-bottom: 11px;
    border: 1px solid #b5cce6;
    border-radius: 50%;
    color: var(--bsk-about-blue);
    font-size: 12px;
    font-weight: 800;
    letter-spacing: -.03em;
}

.bsk-about-fact strong,
.bsk-about-fact small {
    display: block;
}

.bsk-about-fact strong {
    margin-bottom: 2px;
    font-size: 13px;
}

.bsk-about-fact small {
    color: var(--bsk-about-muted);
    font-size: 11px;
    line-height: 1.35;
}

.bsk-about-hero__media {
    position: relative;
    min-height: 530px;
    overflow: hidden;
    border-radius: var(--bsk-about-radius);
    background: #0a1e31;
    box-shadow: 0 18px 55px rgba(4,40,75,.16);
}

.bsk-about-video {
    width: 100%;
    height: 100%;
    min-height: 530px;
    object-fit: cover;
}

.bsk-about-video-button {
    position: absolute;
    inset: 50% auto auto 50%;
    width: 84px;
    height: 84px;
    padding: 0;
    transform: translate(-50%, -50%);
    border: 0;
    border-radius: 50%;
    background: rgba(255,255,255,.96);
    box-shadow: 0 12px 36px rgba(0,0,0,.24);
    cursor: pointer;
    transition: transform .2s ease, opacity .2s ease;
}

.bsk-about-video-button:hover {
    transform: translate(-50%, -50%) scale(1.05);
}

.bsk-about-video-button span {
    display: block;
    width: 0;
    height: 0;
    margin: auto;
    border-top: 12px solid transparent;
    border-bottom: 12px solid transparent;
    border-left: 19px solid var(--bsk-about-navy);
    transform: translateX(3px);
}

.bsk-about-video-button.is-playing {
    opacity: 0;
    pointer-events: none;
}

.bsk-about-video-note {
    position: absolute;
    right: 18px;
    bottom: 16px;
    padding: 8px 12px;
    color: #fff;
    background: rgba(5,38,69,.74);
    backdrop-filter: blur(6px);
    font-size: 12px;
}

/* PRODUCTION */
.bsk-about-production {
    background: var(--bsk-about-soft);
}

.bsk-about-production__grid {
    display: grid;
    grid-template-columns: minmax(320px, .8fr) minmax(0, 1.2fr);
    gap: clamp(44px, 7vw, 100px);
    align-items: center;
}

.bsk-about-production__media {
    height: 520px;
    margin: 0;
    overflow: hidden;
    border-radius: var(--bsk-about-radius);
}

.bsk-about-production__media img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.bsk-about-production__content > p {
    max-width: 760px;
    color: var(--bsk-about-muted);
    font-size: 17px;
}

.bsk-about-checks {
    display: grid;
    gap: 13px;
    margin: 27px 0 0;
    padding: 0;
    list-style: none;
}

.bsk-about-checks li {
    position: relative;
    padding-left: 28px;
}

.bsk-about-checks li::before {
    content: "✓";
    position: absolute;
    left: 0;
    top: 0;
    color: var(--bsk-about-blue);
    font-weight: 900;
}

/* RAZIONAL placeholder */
.bsk-about-rs-placeholder {
    position: relative;
    min-height: 650px;
    display: flex;
    align-items: center;
    color: #fff;
    background:
        linear-gradient(rgba(4,24,42,.48), rgba(4,24,42,.72)),
        url("https://ooo-bsk.ru/wa-data/public/site/custom_img/76.970.jpg") center 45% / cover no-repeat;
}

.bsk-about-rs-placeholder__shade {
    position: absolute;
    inset: 0;
    background: linear-gradient(90deg, rgba(3,26,48,.88) 0%, rgba(3,26,48,.58) 52%, rgba(3,26,48,.22) 100%);
}

.bsk-about-rs-placeholder__content {
    position: relative;
    z-index: 1;
}

.bsk-about-rs-placeholder h2 {
    max-width: 780px;
    margin: 0 0 25px;
    font-size: clamp(42px, 5vw, 72px);
    line-height: 1.04;
    letter-spacing: -.035em;
}

.bsk-about-rs-placeholder p {
    max-width: 610px;
    margin: 0;
    color: rgba(255,255,255,.78);
    font-size: 18px;
}

.bsk-about-process {
    position: absolute;
    top: 50%;
    right: 0;
    display: grid;
    gap: 21px;
    width: 230px;
    transform: translateY(-50%);
}

.bsk-about-process span {
    display: grid;
    grid-template-columns: 46px 1fr;
    gap: 12px;
    align-items: start;
    color: rgba(255,255,255,.85);
    font-size: 13px;
}

.bsk-about-process b {
    color: #fff;
    font-size: 23px;
    line-height: 1;
}

/* PRODUCTS */
.bsk-about-products__grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 24px;
}

.bsk-about-product-card {
    display: block;
    overflow: hidden;
    border: 1px solid var(--bsk-about-line);
    border-radius: var(--bsk-about-radius);
    color: #fff;
    background: var(--bsk-about-navy);
    transition: transform .25s ease, box-shadow .25s ease;
}

.bsk-about-product-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 18px 38px rgba(4,40,75,.14);
}

.bsk-about-product-card__image {
    height: 245px;
    background-position: center;
    background-size: cover;
}

.bsk-about-product-card__image--gaskets {
    background-image:
        linear-gradient(rgba(255,255,255,.03), rgba(255,255,255,.03)),
        url("https://ooo-bsk.ru/wa-data/public/site/custom_img/76.970.jpg");
}

.bsk-about-product-card__image--flanges {
    background-image:
        linear-gradient(rgba(255,255,255,.03), rgba(255,255,255,.03)),
        url("https://ooo-bsk.ru/wa-data/public/site/custom_img/76.970.jpg");
    background-position: center 58%;
}

.bsk-about-product-card__image--blinds {
    background:
        radial-gradient(circle at 55% 50%, #eef2f5 0 21%, #9ba9b7 22% 28%, #dbe1e6 29% 42%, transparent 43%),
        radial-gradient(circle at 50% 50%, #d9e0e6 0 44%, #8c9cab 45% 47%, transparent 48%),
        linear-gradient(135deg, #f3f6f8, #dce4eb);
}

.bsk-about-product-card__body {
    min-height: 205px;
    padding: 24px;
}

.bsk-about-product-card h3 {
    margin: 0 0 12px;
    color: #fff;
    font-size: 21px;
}

.bsk-about-product-card p {
    min-height: 66px;
    margin: 0 0 18px;
    color: rgba(255,255,255,.72);
    font-size: 14px;
}

.bsk-about-product-card span {
    color: #fff;
    font-weight: 700;
    font-size: 13px;
}

/* STANDARDS */
.bsk-about-standards {
    background: var(--bsk-about-soft);
}

.bsk-about-standards__grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 80px;
    align-items: center;
}

.bsk-about-standards__grid p {
    max-width: 600px;
    margin: 0;
    color: var(--bsk-about-muted);
}

.bsk-about-standards__list {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 14px;
}

.bsk-about-standards__list a {
    display: flex;
    min-height: 112px;
    align-items: center;
    justify-content: center;
    border: 1px solid var(--bsk-about-line);
    color: var(--bsk-about-blue);
    background: #fff;
    font-size: clamp(21px, 2vw, 31px);
    font-weight: 800;
    transition: border-color .2s ease, transform .2s ease;
}

.bsk-about-standards__list a:hover {
    transform: translateY(-3px);
    border-color: #8db3dd;
}

.bsk-about-standards__button {
    margin-top: 18px;
}

/* CERTIFICATES */
.bsk-about-certificates {
    background: #fff;
}

.bsk-about-slider {
    position: relative;
}

.bsk-about-slider__viewport {
    overflow: hidden;
}

.bsk-about-slider__track {
    display: flex;
    gap: 18px;
    transition: transform .45s cubic-bezier(.2,.7,.2,1);
    will-change: transform;
}

.bsk-about-certificate {
    flex: 0 0 calc((100% - 72px) / 5);
    min-width: 0;
    color: var(--bsk-about-text);
}

.bsk-about-certificate__paper {
    position: relative;
    display: flex;
    aspect-ratio: .72;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 30px 18px;
    overflow: hidden;
    border: 1px solid #cad4de;
    background:
        linear-gradient(135deg, transparent 0 14px, rgba(7,88,184,.08) 14px 16px, transparent 16px),
        #fff;
    box-shadow: 0 9px 22px rgba(25,48,77,.08);
    text-align: center;
}

.bsk-about-certificate__paper::before {
    content: "";
    position: absolute;
    inset: 14px;
    border: 1px solid rgba(7,88,184,.32);
    pointer-events: none;
}

.bsk-about-certificate__paper::after {
    content: "БСК";
    position: absolute;
    right: 21px;
    bottom: 24px;
    display: flex;
    width: 58px;
    height: 58px;
    align-items: center;
    justify-content: center;
    border: 2px solid rgba(7,88,184,.42);
    border-radius: 50%;
    color: rgba(7,88,184,.56);
    font-size: 12px;
    font-weight: 800;
    transform: rotate(-10deg);
}

.bsk-about-certificate__paper b,
.bsk-about-certificate__paper i,
.bsk-about-certificate__paper em {
    position: relative;
    z-index: 1;
}

.bsk-about-certificate__paper b {
    margin-bottom: 18px;
    color: var(--bsk-about-blue);
    font-size: 15px;
    letter-spacing: .06em;
}

.bsk-about-certificate__paper i {
    max-width: 140px;
    margin-bottom: 24px;
    color: #405268;
    font-size: 12px;
    font-style: normal;
}

.bsk-about-certificate__paper em {
    color: #7a8796;
    font-size: 10px;
    font-style: normal;
}

.bsk-about-slider__arrow {
    position: absolute;
    z-index: 2;
    top: 50%;
    width: 48px;
    height: 64px;
    padding: 0;
    transform: translateY(-50%);
    border: 0;
    color: var(--bsk-about-navy);
    background: rgba(255,255,255,.9);
    font-size: 42px;
    line-height: 1;
    cursor: pointer;
}

.bsk-about-slider__arrow:disabled {
    opacity: .2;
    cursor: default;
}

.bsk-about-slider__arrow--prev {
    left: -58px;
}

.bsk-about-slider__arrow--next {
    right: -58px;
}

.bsk-about-slider__dots {
    display: flex;
    justify-content: center;
    gap: 7px;
    margin-top: 22px;
}

.bsk-about-slider__dots span {
    width: 7px;
    height: 7px;
    border-radius: 50%;
    background: #c7d1dc;
}

.bsk-about-slider__dots span.is-active {
    background: var(--bsk-about-blue);
}

.bsk-about-certificates__footer {
    display: flex;
    justify-content: center;
    margin-top: 24px;
}

/* CTA */
.bsk-about-cta {
    position: relative;
    overflow: hidden;
    color: #fff;
    background:
        linear-gradient(90deg, #052c50 0%, #063b6b 58%, #052a4c 100%);
}

.bsk-about-cta__drawing {
    position: absolute;
    inset: 0;
    opacity: .17;
    background-image:
        linear-gradient(90deg, transparent 49.5%, rgba(255,255,255,.33) 50%, transparent 50.5%),
        linear-gradient(transparent 49.5%, rgba(255,255,255,.24) 50%, transparent 50.5%);
    background-size: 88px 88px;
    transform: rotate(-7deg) scale(1.2);
}

.bsk-about-cta__grid {
    position: relative;
    z-index: 1;
    display: grid;
    grid-template-columns: 1fr .8fr;
    min-height: 430px;
    align-items: center;
}

.bsk-about-cta__content {
    max-width: 700px;
    padding: 76px 0;
}

.bsk-about-cta h2 {
    margin: 0 0 20px;
    color: #fff;
    font-size: clamp(38px, 4.2vw, 62px);
    line-height: 1.03;
    letter-spacing: -.035em;
}

.bsk-about-cta p {
    max-width: 630px;
    margin: 0 0 30px;
    color: rgba(255,255,255,.77);
}

.bsk-about-cta__flange {
    position: relative;
    align-self: stretch;
}

.bsk-about-cta__flange::before,
.bsk-about-cta__flange::after,
.bsk-about-cta__flange span {
    position: absolute;
    content: "";
    border-radius: 50%;
}

.bsk-about-cta__flange::before {
    width: 540px;
    height: 540px;
    right: -155px;
    bottom: -175px;
    background:
        radial-gradient(circle at center,
            #19354f 0 21%,
            #dbe2e8 22% 28%,
            #768a9b 29% 31%,
            #d5dde3 32% 55%,
            #8396a6 56% 59%,
            #ccd5dc 60% 67%,
            #64798b 68% 70%,
            transparent 71%);
    box-shadow: inset -18px -24px 50px rgba(0,0,0,.28), 0 25px 45px rgba(0,0,0,.24);
}

.bsk-about-cta__flange::after {
    width: 36px;
    height: 36px;
    right: 245px;
    bottom: 235px;
    background: #23455f;
    box-shadow:
        110px -75px 0 #23455f,
        178px 26px 0 #23455f,
        93px 124px 0 #23455f,
        -25px 96px 0 #23455f;
}

/* Responsive */
@media (max-width: 1180px) {
    .bsk-about-hero__grid {
        grid-template-columns: 1fr 1fr;
        gap: 44px;
    }

    .bsk-about-facts {
        grid-template-columns: repeat(2, 1fr);
    }

    .bsk-about-process {
        position: static;
        width: min(100%, 600px);
        margin-top: 48px;
        transform: none;
        grid-template-columns: repeat(2, 1fr);
    }

    .bsk-about-certificate {
        flex-basis: calc((100% - 54px) / 4);
    }

    .bsk-about-slider__arrow--prev {
        left: 0;
    }

    .bsk-about-slider__arrow--next {
        right: 0;
    }
}

@media (max-width: 900px) {
    .bsk-about-container {
        width: min(calc(100% - 32px), var(--bsk-about-container));
    }

    .bsk-about-section {
        padding: 64px 0;
    }

    .bsk-about-hero {
        padding-top: 30px;
    }

    .bsk-about-hero__grid,
    .bsk-about-production__grid,
    .bsk-about-standards__grid,
    .bsk-about-cta__grid {
        grid-template-columns: 1fr;
    }

    .bsk-about-hero__media {
        min-height: 430px;
    }

    .bsk-about-video {
        min-height: 430px;
    }

    .bsk-about-production__media {
        height: 430px;
    }

    .bsk-about-products__grid {
        grid-template-columns: 1fr 1fr;
    }

    .bsk-about-standards__grid {
        gap: 36px;
    }

    .bsk-about-certificate {
        flex-basis: calc((100% - 36px) / 3);
    }

    .bsk-about-cta__grid {
        min-height: auto;
    }

    .bsk-about-cta__flange {
        min-height: 260px;
    }

    .bsk-about-cta__flange::before {
        right: 50%;
        bottom: -280px;
        transform: translateX(50%);
    }
}

@media (max-width: 640px) {
    .bsk-about-container {
        width: min(calc(100% - 24px), var(--bsk-about-container));
    }

    .bsk-about-section {
        padding: 52px 0;
    }

    .bsk-about-hero__title {
        font-size: 46px;
    }

    .bsk-about-hero__lead {
        font-size: 17px;
    }

    .bsk-about-facts {
        gap: 20px 12px;
    }

    .bsk-about-actions {
        display: grid;
        grid-template-columns: 1fr;
    }

    .bsk-about-btn {
        width: 100%;
    }

    .bsk-about-hero__media,
    .bsk-about-video {
        min-height: 320px;
    }

    .bsk-about-production__media {
        height: 340px;
    }

    .bsk-about-rs-placeholder {
        min-height: 590px;
    }

    .bsk-about-rs-placeholder h2 {
        font-size: 43px;
    }

    .bsk-about-process {
        grid-template-columns: 1fr;
    }

    .bsk-about-products__grid {
        grid-template-columns: 1fr;
    }

    .bsk-about-product-card__image {
        height: 230px;
    }

    .bsk-about-standards__list {
        grid-template-columns: repeat(2, 1fr);
    }

    .bsk-about-certificate {
        flex-basis: calc((100% - 18px) / 2);
    }

    .bsk-about-slider__arrow {
        width: 40px;
        height: 56px;
    }
}

@media (max-width: 420px) {
    .bsk-about-facts {
        grid-template-columns: 1fr 1fr;
    }

    .bsk-about-certificate {
        flex-basis: 84%;
    }

    .bsk-about-standards__list a {
        min-height: 92px;
    }
}

@media (prefers-reduced-motion: reduce) {
    .bsk-about *,
    .bsk-about *::before,
    .bsk-about *::after {
        scroll-behavior: auto !important;
        transition-duration: .01ms !important;
        animation-duration: .01ms !important;
        animation-iteration-count: 1 !important;
    }
}