/* DSFM — BPF layout */

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

:root {
    --nav-h: 7.2rem;
    --logo-band: clamp(8.5rem, 16.5vw, 22rem);
    --page-x: 2rem;
    --section-gap: clamp(22rem, 32vh, 38rem);
    --letter-gutter-left: clamp(13rem, 22vw, 28rem);
    --letter-gutter-right: clamp(11rem, 18vw, 24rem);
    --letter-color: #707070;
    --font-sans: "Public Sans", "Helvetica Neue", Helvetica, Arial, sans-serif;
    --font-display: "Helvetica Neue", Helvetica, Arial, sans-serif;
    --bg: #000;
    --text: #fff;
    --text-muted: #999;
    --text-soft: #bbb;
    --border: #fff;
    --media-bg: #1a1a1a;
    --radius-sm: clamp(0.55rem, 1.2vw, 0.85rem);
    --radius-md: clamp(0.85rem, 1.8vw, 1.25rem);
    --radius-lg: clamp(1rem, 2.2vw, 1.5rem);
}

html { font-size: 62.5%; scroll-behavior: auto; }
html.lenis, html.lenis body { height: auto; }
.lenis.lenis-smooth { scroll-behavior: auto !important; }

body {
    margin: 0;
    background: var(--bg);
    color: var(--text);
    font-family: var(--font-sans);
    font-size: 1.6rem;
    line-height: 1.5;
    -webkit-font-smoothing: antialiased;
}

#smooth-content {
    background: var(--bg);
}

a { color: inherit; text-decoration: none; }
img, video { display: block; max-width: 100%; }

/* ── Nav ── */
.dsfm-nav {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 300;
    height: var(--nav-h);
    padding: 2rem max(var(--page-x), env(safe-area-inset-right, 0px)) 0 max(var(--page-x), env(safe-area-inset-left, 0px));
    background: var(--bg);
    pointer-events: none;
    transition: opacity 0.3s ease, visibility 0.3s ease, transform 0.3s ease;
}

.dsfm-nav ul {
    list-style: none;
    margin: 0;
    padding: 0;
    display: flex;
    flex-wrap: wrap;
    gap: 1rem 2.2rem;
    pointer-events: auto;
}

.dsfm-nav a {
    font-size: 1.05rem;
    font-weight: 600;
    letter-spacing: 0.14em;
    text-transform: uppercase;
    padding-bottom: 0.5rem;
    position: relative;
}

.dsfm-nav a.is-active::after {
    content: "";
    position: absolute;
    left: 0;
    right: 0;
    bottom: 0;
    height: 2px;
    background: var(--text);
}

/* ── Logo：位置/字号由 JS 随滚动插值 ── */
.logo-wrap {
    position: fixed;
    z-index: 250;
    left: var(--page-x);
    right: var(--page-x);
    pointer-events: none;
    overflow: visible;
    top: auto;
    bottom: 2rem;
    height: clamp(8rem, 20vw, 20rem);
    isolation: isolate;
    transform: translateZ(0);
}

.logo {
    position: relative;
    width: 100%;
    height: 100%;
}

.logo-letter {
    position: absolute;
    bottom: 0;
    left: 0;
    margin: 0;
    padding: 0;
    font-family: var(--font-display);
    font-size: clamp(5rem, 17vw, 22rem);
    font-weight: 900;
    line-height: 0.86;
    letter-spacing: -0.02em;
    color: var(--letter-color);
    -webkit-text-stroke: 0;
    paint-order: normal;
    white-space: nowrap;
    will-change: transform;
    transform: translateX(0) translateZ(0);
    backface-visibility: hidden;
}

/* ── Intro：全屏居中 banner ── */
.intro {
    min-height: 100dvh;
    display: flex;
    flex-direction: column;
    padding: var(--nav-h) var(--page-x) clamp(16rem, 22vw, 24rem);
}

.intro-video-wrap {
    flex: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 0;
}

.intro-video {
    width: 100%;
    max-width: 50%;
    aspect-ratio: 719 / 538;
    object-fit: cover;
    border-radius: var(--radius-sm);
    background: #111;
}

.block-media,
.block-section-media,
.about-media {
    border-radius: var(--radius-sm);
}

.block-media img,
.block-section-media img,
.about-media img {
    border-radius: inherit;
}

/* ── Blocks ── */
.block {
    padding: 5rem var(--page-x) clamp(12rem, 18vh, 22rem);
    min-height: 55vh;
}

.block--home {
    padding-top: calc(var(--logo-band) + var(--section-gap));
    padding-bottom: clamp(16rem, 24vh, 32rem);
    min-height: calc(100dvh - var(--nav-h));
}

/* 各模块顶部留白：字母在此区域变换，正文在留白下方 */
.block--center,
.block--text-left,
.block--contact {
    padding-top: calc(var(--logo-band) + var(--section-gap));
}

.block--home.block--bpf-split .block-stage {
    display: flex;
    flex-direction: column;
    align-items: stretch;
    width: min(44rem, calc(
        100% - var(--about-gutter-left, var(--letter-gutter-left))
              - var(--about-gutter-right, var(--letter-gutter-right))
    ));
    max-width: 44rem;
    margin-left: auto;
    margin-right: calc(var(--about-gutter-right, var(--letter-gutter-right)) + 0.25rem);
    padding: 0;
    box-sizing: border-box;
}

.block--home.block--bpf-split .block-inner {
    width: 100%;
    max-width: 44rem;
    margin: 0;
    padding: 0;
    text-align: left;
}

.block-body--home {
    max-width: none;
    text-align: left;
}

.block-grid,
.block-stage,
.about-inner {
    position: relative;
}

.block-section-media,
.about-media {
    position: relative;
    z-index: 1;
    transform: translateZ(0);
}

.block-col-left {
    display: flex;
    flex-direction: column;
    justify-content: center;
}

.block-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 3rem;
    max-width: 140rem;
    margin: 0 auto;
}

.block-label {
    font-size: 1rem;
    font-weight: 700;
    letter-spacing: 0.16em;
    text-transform: uppercase;
    margin: 0 0 1.4rem;
    padding-bottom: 1rem;
    border-bottom: 2px solid var(--border);
}

.block-heading {
    font-size: clamp(2.8rem, 5vw, 6rem);
    font-weight: 900;
    line-height: 1.02;
    text-transform: uppercase;
    margin: 0 0 1.4rem;
}

.block--section-title .block-heading {
    padding-bottom: 1.2rem;
    border-bottom: 2px solid var(--border);
    margin-bottom: 1.4rem;
}

.block-subheading {
    font-size: 1.05rem;
    font-weight: 700;
    letter-spacing: 0.12em;
    text-transform: uppercase;
    margin: 0 0 1rem;
}

.block-body {
    font-size: clamp(1.45rem, 1.7vw, 1.95rem);
    line-height: 1.55;
    max-width: 50rem;
}

.block-body p { margin: 0 0 1.2rem; }
.block-body p:last-child { margin-bottom: 0; }

.block--home .block-body,
.block-body--home {
    font-size: clamp(1.65rem, 2vw, 2.6rem);
}

.block-media {
    overflow: hidden;
    background: var(--media-bg);
    min-height: 28rem;
}

.block-media img {
    width: 100%;
    height: 100%;
    min-height: 28rem;
    object-fit: cover;
}

/* ── BPF 分区排版 ── */
.block-stage {
    width: 100%;
    max-width: none;
    margin: 0;
}

.block-section-media {
    margin: 0;
    overflow: hidden;
    background: var(--media-bg);
}

.block-section-media img {
    display: block;
    width: 100%;
    height: auto;
    object-fit: cover;
}

/* What We Do / Our Goal：正文栏居中，两侧留给字母 */
.block--bpf-split .block-stage,
.block--bpf-stack .block-stage {
    display: flex;
    flex-direction: column;
    align-items: stretch;
    width: min(44rem, calc(100% - var(--letter-gutter-left) - var(--letter-gutter-right)));
    max-width: 44rem;
    margin: 0 auto;
    padding: 0;
    box-sizing: border-box;
}

.block--bpf-split .block-inner,
.block--bpf-stack .block-inner {
    width: 100%;
    max-width: 44rem;
    margin: 0;
    padding: 0;
    text-align: left;
}

.block--bpf-split .block-body,
.block--bpf-stack .block-body {
    max-width: none;
}

.block--bpf-split .block-section-media,
.block--bpf-stack .block-section-media {
    width: 100%;
    max-width: 44rem;
    margin-top: clamp(3rem, 5vw, 5rem);
    margin-bottom: clamp(8rem, 14vh, 16rem);
}

.block--before-philanthropy {
    padding-bottom: clamp(18rem, 28vh, 36rem);
}

.block--bpf-split .block-section-media img,
.block--bpf-stack .block-section-media img {
    width: 100%;
    aspect-ratio: 16 / 10;
    min-height: 16rem;
    max-height: 40vh;
    object-fit: cover;
}

.block--natural-media .block-section-media img {
    width: 100%;
    height: auto;
    aspect-ratio: auto;
    min-height: 0;
    max-height: none;
    object-fit: contain;
}

/* Philanthropy：内容固定靠左，字母固定靠右 */
.block--bpf-philanthropy .block-stage {
    display: flex;
    flex-direction: column;
    align-items: stretch;
    width: min(44rem, calc(100% - var(--page-x) * 2));
    max-width: 44rem;
    margin-left: var(--page-x);
    margin-right: auto;
    padding: 0;
}

.block--bpf-philanthropy .block-inner {
    max-width: none;
    width: 100%;
    margin: 0;
}

.block--bpf-philanthropy .block-section-media {
    width: 100%;
    margin-top: clamp(3rem, 5vw, 5rem);
    align-self: stretch;
}

.block--bpf-philanthropy .block-section-media img {
    width: 100%;
    aspect-ratio: 1 / 1;
    min-height: 18rem;
    max-height: 44vh;
    object-fit: cover;
}

.block--contact {
    text-align: center;
    display: flex;
    flex-direction: column;
    justify-content: flex-end;
    min-height: 100dvh;
    padding-top: calc(var(--logo-band) + clamp(6rem, 12vh, 14rem));
    padding-bottom: clamp(3rem, 5vh, 5rem);
}

.block--contact .contact-locations-row,
.block--contact .site-footer {
    margin-left: auto;
    margin-right: auto;
    padding-left: var(--page-x);
    padding-right: var(--page-x);
    max-width: 86rem;
    width: 100%;
}

.contact-locations-row {
    display: flex;
    justify-content: center;
    gap: 3rem;
    flex-wrap: wrap;
    margin-bottom: 4rem;
    font-size: 1.25rem;
    color: var(--text-soft);
}

.site-footer {
    max-width: 86rem;
    margin: 0 auto;
    font-size: 1.1rem;
    line-height: 1.65;
    color: var(--text-muted);
}

.site-footer p { margin: 0 0 1rem; }
.site-footer .copyright { color: var(--text-soft); }

/* About Us — DSF 左 | M 右，内容靠右贴近 M */
.block--about {
    min-height: calc(100dvh - var(--nav-h));
    padding-top: calc(var(--logo-band) + var(--section-gap));
    padding-bottom: clamp(18rem, 28vh, 36rem);
}

.about-inner {
    width: calc(
        100% - var(--about-gutter-left, var(--letter-gutter-left))
              - var(--about-gutter-right, var(--letter-gutter-right))
    );
    max-width: min(76rem, 100%);
    margin-left: auto;
    margin-right: calc(var(--about-gutter-right, var(--letter-gutter-right)) + 0.25rem);
    box-sizing: border-box;
}

.about-byline {
    margin: 0 0 1.2rem;
    font-weight: 400;
}

.about-content {
    display: grid;
    grid-template-columns: 1fr;
    gap: 2.5rem;
    padding-top: 2.4rem;
}

.about-text {
    max-width: none;
    font-size: clamp(1.35rem, 1.55vw, 1.85rem);
    line-height: 1.58;
}

.about-media {
    margin: 0;
    overflow: hidden;
    background: var(--media-bg);
    flex-shrink: 0;
}

.about-media img {
    display: block;
    width: 100%;
    height: auto;
    min-height: 0;
    object-fit: cover;
    aspect-ratio: 3 / 4;
}

@media (min-width: 768px) and (max-width: 1023px) {
    :root {
        --nav-h: 7.6rem;
        --page-x: 1.75rem;
        --section-gap: clamp(14rem, 24vh, 26rem);
        --logo-band: clamp(7rem, 13vw, 11rem);
    }

    .intro-video {
        max-width: 68%;
        border-radius: var(--radius-md);
    }

    .block {
        padding: 4.5rem var(--page-x) clamp(10rem, 16vh, 18rem);
    }

    .block--home .block-body,
    .block-body--home {
        font-size: clamp(1.5rem, 2.2vw, 2rem);
    }

    .block--home.block--bpf-split .block-stage {
        width: min(40rem, calc(
            100% - var(--about-gutter-left, var(--letter-gutter-left))
                  - var(--about-gutter-right, var(--letter-gutter-right))
        ));
        margin-left: auto;
        margin-right: calc(var(--about-gutter-right, var(--letter-gutter-right)) + 0.25rem);
    }

    .block-body {
        font-size: clamp(1.35rem, 1.9vw, 1.75rem);
    }

    .block--bpf-split .block-stage,
    .block--bpf-stack .block-stage {
        width: min(40rem, calc(100% - var(--letter-gutter-left) - var(--letter-gutter-right)));
        max-width: 40rem;
    }

    .block--bpf-split .block-inner,
    .block--bpf-stack .block-inner,
    .block--bpf-split .block-section-media,
    .block--bpf-stack .block-section-media {
        max-width: 40rem;
    }

    .block--bpf-philanthropy .block-stage {
        max-width: min(40rem, 52vw);
    }

    .about-inner {
        max-width: min(68rem, calc(
            100% - var(--about-gutter-left, var(--letter-gutter-left))
                  - var(--about-gutter-right, var(--letter-gutter-right))
        ));
        margin-left: auto;
        margin-right: calc(var(--about-gutter-right, var(--letter-gutter-right)) + 0.25rem);
    }

    .about-content {
        grid-template-columns: minmax(0, 1fr) clamp(16rem, 22vw, 24rem);
        gap: 2.5rem 3.5rem;
    }

    .about-text {
        max-width: 30rem;
        font-size: clamp(1.25rem, 1.7vw, 1.55rem);
    }

    .about-media {
        width: clamp(16rem, 22vw, 24rem);
    }

    .about-media img {
        min-height: 34rem;
        max-height: 58vh;
        aspect-ratio: 3 / 4;
    }

    .dsfm-nav ul {
        gap: 0.85rem 1.8rem;
    }

    .block-grid--2 {
        grid-template-columns: 1fr 1fr;
        gap: 2rem 3.5rem;
    }
}

@media (min-width: 1024px) {
    :root { --nav-h: 8.4rem; }

    .intro-video {
        border-radius: var(--radius-sm);
    }

    .block-grid--2 {
        grid-template-columns: 1fr 1fr;
        gap: 2rem 5rem;
        align-items: stretch;
    }

    .block--home .block-grid--2 {
        align-items: start;
    }

    .block--bpf-philanthropy .block-stage {
        max-width: min(44rem, 40vw);
    }

    .about-inner {
        max-width: min(78rem, calc(
            100% - var(--about-gutter-left, var(--letter-gutter-left))
                  - var(--about-gutter-right, var(--letter-gutter-right))
        ));
        margin-left: auto;
        margin-right: calc(var(--about-gutter-right, var(--letter-gutter-right)) + 0.25rem);
    }

    .about-content {
        grid-template-columns: minmax(0, 1fr) clamp(18rem, 24vw, 28rem);
        gap: 3rem 4.5rem;
        align-items: start;
    }

    .about-text {
        max-width: 36rem;
    }

    .about-media {
        width: clamp(18rem, 24vw, 28rem);
    }

    .about-media img {
        aspect-ratio: 3 / 4;
        min-height: 42rem;
        max-height: 65vh;
    }

    .block-media,
    .block-media img { min-height: 52vh; }
}

@media (max-width: 767px) {
    :root {
        --nav-h: 5.6rem;
        --logo-band: clamp(4.8rem, 13vw, 6.2rem);
        --mobile-logo-band: clamp(4.8rem, 13vw, 6.2rem);
        --page-x: 1.25rem;
        --section-gap: clamp(4rem, 10vh, 7rem);
    }

    .block {
        padding-left: max(var(--page-x), env(safe-area-inset-left, 0px));
        padding-right: max(var(--page-x), env(safe-area-inset-right, 0px));
    }

    .logo-wrap {
        padding-left: max(var(--page-x), env(safe-area-inset-left, 0px));
        padding-right: max(var(--page-x), env(safe-area-inset-right, 0px));
    }

    .dsfm-nav {
        padding-top: max(1.4rem, env(safe-area-inset-top, 0px));
    }

    .dsfm-nav ul {
        gap: 0.65rem 1.25rem;
    }

    .dsfm-nav a {
        font-size: 0.88rem;
        letter-spacing: 0.12em;
    }

    .block-heading {
        font-size: clamp(2.15rem, 8.5vw, 3.4rem);
        margin-bottom: 1rem;
    }

    .block-label {
        font-size: 0.9rem;
        margin-bottom: 1rem;
    }

    .block--home .block-body,
    .block-body--home {
        font-size: clamp(1.42rem, 4.1vw, 1.68rem);
        line-height: 1.52;
    }

    .block-body {
        font-size: clamp(1.32rem, 3.8vw, 1.52rem);
        line-height: 1.52;
    }

    .about-text {
        font-size: clamp(1.32rem, 3.8vw, 1.52rem);
    }

    .block--about {
        min-height: auto;
    }

    .block-media img {
        min-height: clamp(16rem, 48vw, 24rem);
    }

    .block-section-media img {
        border-radius: var(--radius-md);
        max-height: none;
    }

    .about-media {
        border-radius: var(--radius-md);
    }

    .about-media img {
        min-height: clamp(20rem, 62vw, 30rem);
        aspect-ratio: 3 / 4;
    }

    .contact-locations-row {
        gap: 1.5rem 2rem;
        font-size: 1.1rem;
        margin-bottom: 2.5rem;
    }

    .site-footer {
        font-size: 1rem;
        line-height: 1.6;
    }

    /* 手机：开始滚动后导航隐藏 */
    body.is-nav-hidden .dsfm-nav,
    body.is-logo-docked .dsfm-nav {
        opacity: 0;
        visibility: hidden;
        pointer-events: none;
        transform: translateY(-0.75rem);
    }

    .logo-wrap {
        left: 0;
        right: 0;
        padding: 0 var(--page-x);
        z-index: 280;
        background: transparent;
        overflow: visible;
        pointer-events: none;
    }

    body.is-logo-docked .logo-wrap {
        padding-bottom: 0.4rem;
    }

    .logo {
        margin: 0 auto;
        max-width: 100%;
        display: flex;
        justify-content: center;
        align-items: flex-end;
        gap: clamp(0.15rem, 1.2vw, 0.55rem);
        padding-bottom: 0.25rem;
        min-height: 100%;
    }

    .logo-letter {
        position: relative !important;
        left: auto !important;
        bottom: auto !important;
        flex: 0 0 auto;
        color: var(--letter-color) !important;
        -webkit-text-stroke: 0 !important;
        letter-spacing: -0.04em;
        line-height: 0.9;
        transform: none !important;
    }

    .intro {
        min-height: 100dvh;
        padding: calc(var(--nav-h) + 0.75rem) var(--page-x) clamp(7rem, 24vw, 10rem);
    }

    .intro-video {
        max-width: 100%;
        border-radius: var(--radius-lg);
    }

    .block {
        padding: 3rem var(--page-x) 4.5rem;
    }

    .block--home {
        padding-top: var(--mobile-content-offset, 0px);
        min-height: auto;
        padding-bottom: 4rem;
    }

    .block--center,
    .block--text-left,
    .block--about,
    .block--contact {
        padding-top: var(--mobile-content-offset, 0px);
    }

    body.is-logo-docked .block--home,
    body.is-logo-docked .block--center,
    body.is-logo-docked .block--text-left,
    body.is-logo-docked .block--about,
    body.is-logo-docked .block--contact {
        padding-top: calc(var(--mobile-logo-band) + 0.75rem);
    }

    .about-inner {
        width: 100%;
        max-width: none;
    }

    .about-media img {
        min-height: 28rem;
        max-height: none;
    }

    .block--bpf-philanthropy .block-stage {
        max-width: none;
        margin-left: 0;
        padding: 0;
    }

    .block--bpf-split .block-stage,
    .block--bpf-stack .block-stage {
        width: 100%;
        max-width: none;
    }

    .block--contact {
        min-height: auto;
        padding-top: var(--mobile-content-offset, 0px);
    }

    body.is-logo-docked .block--contact {
        padding-top: calc(var(--mobile-logo-band) + 0.75rem);
    }
}

@media (prefers-reduced-motion: reduce) {
    .dsfm-nav,
    .logo-letter,
    .logo-wrap {
        transition: none !important;
    }
}