:root {
    --apple-black: #000000;
    --apple-white: #ffffff;
    --apple-text: #1d1d1f;
    --apple-muted: rgba(29, 29, 31, 0.72);
    --apple-soft: rgba(29, 29, 31, 0.56);
    --apple-blue: #0071e3;
    --apple-blue-dark: #2997ff;
    --apple-gray: #f5f5f7;
    --apple-line: rgba(0, 0, 0, 0.08);
    --apple-line-dark: rgba(255, 255, 255, 0.14);
    --apple-card-dark: #1d1d1f;
    --apple-card-soft: #fbfbfd;
    --apple-shadow: rgba(0, 0, 0, 0.22) 3px 5px 30px 0;
    --radius-card: 28px;
    --radius-panel: 22px;
    --radius-button: 999px;
    --max: 1200px;
    --header-h: 56px;
    --rail-h: 68px;
}

* {
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    margin: 0;
    min-height: 100vh;
    background: var(--apple-white);
    color: var(--apple-text);
    font-family:
        "SF Pro Display",
        "SF Pro Text",
        -apple-system,
        BlinkMacSystemFont,
        "Helvetica Neue",
        Arial,
        "PingFang SC",
        "Microsoft YaHei",
        sans-serif;
    text-rendering: optimizeLegibility;
    -webkit-font-smoothing: antialiased;
}

a {
    color: inherit;
    text-decoration: none;
}

button,
input,
textarea {
    font: inherit;
}

button,
a {
    -webkit-tap-highlight-color: transparent;
}

img {
    display: block;
    max-width: 100%;
}

.site-shell {
    min-height: 100vh;
}

.site-header,
.hero-viewport,
.chapter-rail,
.story-section,
.closing-section,
.inside-hero,
.inside-layout,
.unlock-shell,
.noscript-note {
    padding-inline: max(22px, calc((100vw - var(--max)) / 2));
}

.site-header {
    position: sticky;
    top: 0;
    z-index: 30;
    display: grid;
    grid-template-columns: auto 1fr auto;
    align-items: center;
    gap: 28px;
    min-height: var(--header-h);
    background: rgba(0, 0, 0, 0.78);
    color: var(--apple-white);
    backdrop-filter: saturate(180%) blur(20px);
}

.brand {
    display: grid;
    gap: 2px;
    align-self: center;
}

.brand-cn,
.hero-kicker,
.section-kicker,
.panel-index,
.rail-caption,
.source-stack-label {
    margin: 0;
    font-size: 12px;
    font-weight: 400;
    line-height: 1.33;
    letter-spacing: -0.12px;
}

.brand-cn {
    color: rgba(255, 255, 255, 0.68);
}

.brand-en {
    font-size: 14px;
    font-weight: 400;
    line-height: 1.35;
    letter-spacing: -0.224px;
    color: rgba(255, 255, 255, 0.92);
}

.site-nav,
.header-actions,
.button-row,
.badge-row {
    display: flex;
    align-items: center;
    gap: 12px;
}

.site-nav {
    justify-content: center;
    gap: 24px;
    font-size: 12px;
    font-weight: 400;
    letter-spacing: -0.12px;
}

.site-nav a,
.header-link,
.rail-link {
    color: rgba(255, 255, 255, 0.8);
    transition: color 180ms ease, opacity 180ms ease;
}

.site-nav a:hover,
.site-nav a:focus-visible,
.header-link:hover,
.header-link:focus-visible,
.rail-link:hover,
.rail-link:focus-visible {
    color: var(--apple-white);
}

.header-actions {
    justify-content: flex-end;
}

.header-link {
    font-size: 12px;
    font-weight: 400;
    letter-spacing: -0.12px;
}

.button {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-height: 44px;
    padding: 0 18px;
    border: 1px solid transparent;
    border-radius: var(--radius-button);
    font-size: 17px;
    font-weight: 400;
    line-height: 1;
    letter-spacing: -0.374px;
    cursor: pointer;
    transition: transform 180ms ease, background 180ms ease, color 180ms ease, border-color 180ms ease;
}

.button:hover,
.button:focus-visible {
    transform: translateY(-1px);
}

.button-primary {
    background: var(--apple-blue);
    color: var(--apple-white);
}

.button-secondary {
    background: transparent;
    color: currentColor;
    border-color: currentColor;
}

.button-tertiary {
    min-height: auto;
    padding: 0;
    border: none;
    background: transparent;
    color: var(--apple-blue);
}

.hero-surface .button-tertiary,
.tone-dark .button-tertiary,
.unlock-shell .button-tertiary {
    color: var(--apple-blue-dark);
}

.button-compact {
    min-height: 34px;
    padding-inline: 14px;
    font-size: 14px;
    letter-spacing: -0.224px;
}

.button-nav {
    min-height: 34px;
    padding-inline: 12px;
    border-color: rgba(255, 255, 255, 0.22);
    background: rgba(255, 255, 255, 0.08);
    color: var(--apple-white);
    font-size: 12px;
    letter-spacing: -0.12px;
}

.hero-viewport {
    min-height: calc(100svh - var(--header-h));
    padding-top: 72px;
    padding-bottom: 72px;
}

.hero-surface {
    background: var(--apple-black);
    color: var(--apple-white);
}

.hero-copy {
    max-width: 900px;
    margin: 0 auto;
    text-align: center;
}

.hero-kicker,
.section-kicker {
    color: rgba(255, 255, 255, 0.72);
}

.hero-copy h1,
.story-intro h2,
.closing-shell h2,
.inside-hero h1,
.inside-summary h2,
.inside-section-head h2,
.unlock-card h1 {
    margin: 0;
    font-size: clamp(3.25rem, 9vw, 5.75rem);
    font-weight: 600;
    line-height: 1.04;
    letter-spacing: -0.28px;
    text-wrap: balance;
}

.hero-copy h1 span {
    display: block;
}

.hero-lead {
    margin: 16px auto 0;
    max-width: 620px;
    font-size: clamp(1.25rem, 2vw, 1.75rem);
    font-weight: 400;
    line-height: 1.25;
    letter-spacing: 0.231px;
    color: var(--apple-white);
}

.hero-strap,
.story-intro p,
.closing-shell p,
.inside-hero p,
.inside-summary p,
.inside-section-head p,
.unlock-card p,
.panel-block p,
.unlock-feedback {
    margin: 0;
    font-size: 17px;
    font-weight: 400;
    line-height: 1.47;
    letter-spacing: -0.374px;
}

.hero-strap {
    margin: 18px auto 0;
    max-width: 760px;
    color: rgba(255, 255, 255, 0.78);
}

.hero-quote {
    margin: 24px auto 0;
    max-width: 620px;
    font-size: 21px;
    font-weight: 400;
    line-height: 1.19;
    letter-spacing: 0.231px;
    color: rgba(255, 255, 255, 0.88);
}

.button-row {
    flex-wrap: wrap;
}

.hero-actions,
.closing-actions {
    justify-content: center;
    margin-top: 32px;
}

.hero-stage {
    margin: 56px auto 0;
    max-width: 1040px;
    display: grid;
    gap: 18px;
}

.hero-stage-media {
    padding: clamp(20px, 4vw, 36px);
    border-radius: var(--radius-card);
    background: var(--apple-gray);
    box-shadow: var(--apple-shadow);
}

.hero-logo {
    width: min(760px, 100%);
    margin: 0 auto;
    height: auto;
}

.hero-overview {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 14px;
}

.overview-item {
    min-height: 124px;
    padding: 20px;
    border-radius: var(--radius-panel);
    background: rgba(255, 255, 255, 0.06);
    border: 1px solid rgba(255, 255, 255, 0.1);
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    gap: 12px;
}

.overview-item span {
    font-size: 12px;
    line-height: 1.33;
    letter-spacing: -0.12px;
    color: rgba(255, 255, 255, 0.72);
}

.overview-item strong {
    font-size: 21px;
    font-weight: 400;
    line-height: 1.19;
    letter-spacing: 0.231px;
    color: var(--apple-white);
}

.chapter-rail {
    position: sticky;
    top: var(--header-h);
    z-index: 20;
    padding-top: 12px;
    padding-bottom: 12px;
    background: rgba(245, 245, 247, 0.92);
    backdrop-filter: saturate(180%) blur(20px);
    border-bottom: 1px solid var(--apple-line);
}

.chapter-rail-shell {
    min-height: var(--rail-h);
    display: flex;
    align-items: center;
    gap: 12px;
    overflow-x: auto;
    scrollbar-width: none;
}

.chapter-rail-shell::-webkit-scrollbar,
.inside-rail-shell::-webkit-scrollbar {
    display: none;
}

.rail-caption {
    flex: 0 0 auto;
    color: var(--apple-soft);
}

.rail-link {
    flex: 0 0 auto;
    padding: 8px 0;
    color: var(--apple-soft);
    font-size: 14px;
    line-height: 1.43;
    letter-spacing: -0.224px;
}

.chapter-rail .rail-link {
    color: var(--apple-muted);
}

.rail-link.is-active {
    color: var(--apple-text);
}

.story-section,
.closing-section,
.inside-hero,
.inside-layout,
.unlock-shell {
    padding-top: 88px;
    padding-bottom: 88px;
}

.story-section.tone-light,
.closing-section.tone-light {
    background: var(--apple-gray);
    color: var(--apple-text);
}

.story-section.tone-dark {
    background: var(--apple-black);
    color: var(--apple-white);
}

.story-shell,
.inside-layout {
    display: grid;
    grid-template-columns: minmax(260px, 0.4fr) minmax(0, 0.6fr);
    gap: clamp(28px, 4vw, 72px);
    align-items: start;
}

.story-intro {
    position: sticky;
    top: calc(var(--header-h) + var(--rail-h) + 36px);
    display: grid;
    gap: 18px;
}

.tone-light .section-kicker,
.closing-section .section-kicker,
.inside-hero .section-kicker,
.inside-section-head .section-kicker {
    color: var(--apple-soft);
}

.story-intro h2,
.inside-section-head h2,
.inside-summary h2 {
    font-size: clamp(2.5rem, 4vw, 3.6rem);
    line-height: 1.08;
    letter-spacing: -0.28px;
}

.tone-light .story-intro p,
.closing-section p,
.inside-hero p,
.inside-summary p,
.inside-section-head p,
.panel-block p {
    color: var(--apple-muted);
}

.tone-dark .story-intro p {
    color: rgba(255, 255, 255, 0.76);
}

.governance-strip,
.disclosure-panel,
.inside-summary,
.inside-rail-shell,
.unlock-card {
    border-radius: var(--radius-card);
}

.governance-strip {
    padding: 24px;
}

.governance-strip h3,
.panel-block h4 {
    margin: 0;
    font-size: 14px;
    font-weight: 600;
    line-height: 1.43;
    letter-spacing: -0.224px;
}

.tone-light .governance-strip {
    background: var(--apple-white);
    box-shadow: var(--apple-shadow);
}

.tone-dark .governance-strip {
    background: var(--apple-card-dark);
    border: 1px solid var(--apple-line-dark);
}

.story-detail,
.inside-section-body,
.inside-main {
    display: grid;
    gap: 16px;
}

.disclosure-panel {
    overflow: hidden;
}

.tone-light .disclosure-panel,
.inside-summary,
.inside-rail-shell,
.inside .disclosure-panel,
.inside-body .disclosure-panel {
    background: var(--apple-white);
    box-shadow: var(--apple-shadow);
}

.tone-dark .disclosure-panel {
    background: var(--apple-card-dark);
    border: 1px solid var(--apple-line-dark);
}

.disclosure-panel summary {
    position: relative;
    list-style: none;
    display: grid;
    grid-template-columns: 96px 1fr;
    gap: 18px;
    align-items: start;
    padding: 24px;
    cursor: pointer;
}

.disclosure-panel summary::-webkit-details-marker {
    display: none;
}

.disclosure-panel summary::after {
    content: "+";
    position: absolute;
    top: 22px;
    right: 24px;
    font-size: 24px;
    line-height: 1;
    color: inherit;
    opacity: 0.48;
}

.disclosure-panel[open] summary::after {
    content: "−";
}

.panel-heading {
    display: grid;
    gap: 8px;
    padding-right: 40px;
}

.panel-heading strong {
    font-size: 24px;
    font-weight: 400;
    line-height: 1.19;
    letter-spacing: 0.231px;
}

.panel-heading em {
    font-style: normal;
    font-size: 14px;
    line-height: 1.43;
    letter-spacing: -0.224px;
    color: inherit;
    opacity: 0.72;
}

.disclosure-body {
    padding: 0 24px 24px 24px;
    display: grid;
    gap: 18px;
}

.tone-light .disclosure-body,
.inside-body .disclosure-body {
    border-top: 1px solid var(--apple-line);
}

.tone-dark .disclosure-body {
    border-top: 1px solid var(--apple-line-dark);
}

.bullet-list,
.summary-list {
    margin: 0;
    padding-left: 20px;
    display: grid;
    gap: 12px;
    font-size: 17px;
    line-height: 1.47;
    letter-spacing: -0.374px;
}

.tone-light .bullet-list,
.tone-light .summary-list,
.inside-body .bullet-list,
.inside-body .summary-list {
    color: var(--apple-muted);
}

.tone-dark .bullet-list,
.tone-dark .summary-list {
    color: rgba(255, 255, 255, 0.8);
}

.row-list,
.matrix-list {
    margin: 0;
    display: grid;
    gap: 14px;
}

.row-item {
    display: grid;
    grid-template-columns: minmax(132px, 164px) 1fr;
    gap: 18px;
    padding-top: 14px;
}

.tone-light .row-item,
.inside-body .row-item {
    border-top: 1px solid var(--apple-line);
}

.tone-dark .row-item {
    border-top: 1px solid var(--apple-line-dark);
}

.row-item:first-child {
    padding-top: 0;
    border-top: none;
}

.row-item dt {
    margin: 0;
    font-size: 14px;
    font-weight: 600;
    line-height: 1.43;
    letter-spacing: -0.224px;
}

.row-item dd {
    margin: 0;
    font-size: 17px;
    line-height: 1.47;
    letter-spacing: -0.374px;
}

.tone-light .row-item dd,
.inside-body .row-item dd {
    color: var(--apple-muted);
}

.tone-dark .row-item dd {
    color: rgba(255, 255, 255, 0.76);
}

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

.source-stack-items {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
}

.source-chip {
    display: grid;
    gap: 4px;
    padding: 10px 12px;
    border-radius: 16px;
}

.tone-light .source-chip,
.inside-body .source-chip {
    background: rgba(255, 255, 255, 0.72);
}

.tone-dark .source-chip {
    background: rgba(255, 255, 255, 0.08);
}

.source-chip strong {
    font-size: 12px;
    font-weight: 600;
    line-height: 1.33;
    letter-spacing: -0.12px;
}

.source-chip em {
    font-style: normal;
    font-size: 12px;
    line-height: 1.33;
    letter-spacing: -0.12px;
    opacity: 0.64;
}

.closing-shell {
    max-width: 980px;
    margin: 0 auto;
    text-align: center;
    display: grid;
    gap: 18px;
}

.inside-body {
    background: var(--apple-gray);
    color: var(--apple-text);
}

.inside-hero {
    display: grid;
    grid-template-columns: minmax(0, 0.95fr) minmax(320px, 0.78fr);
    gap: clamp(32px, 4vw, 64px);
    align-items: start;
    background: var(--apple-gray);
}

.inside-hero-copy,
.inside-summary {
    display: grid;
    gap: 18px;
}

.inside-summary {
    padding: 28px;
}

.inside-summary-brand {
    max-width: 320px;
}

.inside-brand-logo {
    width: 100%;
    height: auto;
    object-fit: contain;
}

.badge-row {
    flex-wrap: wrap;
}

.status-badge {
    display: inline-flex;
    align-items: center;
    min-height: 30px;
    padding: 0 12px;
    border-radius: 999px;
    background: rgba(0, 113, 227, 0.08);
    color: var(--apple-blue);
    font-size: 12px;
    font-weight: 600;
    line-height: 1.33;
    letter-spacing: -0.12px;
}

.inside-notes {
    display: grid;
    gap: 8px;
}

.inside-layout {
    grid-template-columns: minmax(220px, 0.28fr) minmax(0, 0.72fr);
    gap: clamp(28px, 4vw, 52px);
    align-items: start;
    background: var(--apple-gray);
}

.inside-rail {
    position: sticky;
    top: calc(var(--header-h) + 24px);
}

.inside-rail-shell {
    padding: 20px;
}

.inside-main {
    gap: 80px;
}

.inside-section-head {
    display: grid;
    gap: 16px;
    margin-bottom: 20px;
}

.internal-panel summary {
    grid-template-columns: 80px 1fr;
}

.unlock-shell {
    min-height: calc(100svh - var(--header-h));
    display: grid;
    place-items: center;
}

.unlock-card {
    width: min(100%, 620px);
    padding: 32px;
    background: rgba(29, 29, 31, 0.96);
    color: var(--apple-white);
    border: 1px solid var(--apple-line-dark);
    text-align: center;
    display: grid;
    gap: 18px;
}

.unlock-brand {
    width: min(100%, 380px);
    margin: 0 auto;
}

.unlock-form {
    display: grid;
    grid-template-columns: minmax(0, 1fr) auto;
    gap: 12px;
}

.unlock-form input {
    width: 100%;
    min-height: 44px;
    padding: 0 16px;
    border: 1px solid rgba(255, 255, 255, 0.14);
    border-radius: 14px;
    background: rgba(255, 255, 255, 0.08);
    color: var(--apple-white);
}

.unlock-form input::placeholder {
    color: rgba(255, 255, 255, 0.56);
}

.unlock-feedback {
    min-height: 24px;
    color: #ff9f8f;
}

.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}

.noscript-note {
    padding-top: 120px;
    padding-bottom: 120px;
}

.noscript-note h1 {
    margin: 0 0 12px;
    font-size: 40px;
    line-height: 1.1;
    letter-spacing: -0.28px;
}

.noscript-note p {
    margin: 0;
    color: var(--apple-muted);
    font-size: 17px;
    line-height: 1.47;
    letter-spacing: -0.374px;
}

.reveal {
    opacity: 0;
    transform: translateY(18px);
    transition: opacity 600ms ease, transform 600ms ease;
}

.reveal.is-visible {
    opacity: 1;
    transform: translateY(0);
}

:focus-visible {
    outline: 2px solid var(--apple-blue);
    outline-offset: 2px;
}

@media (max-width: 1120px) {
    .hero-overview {
        grid-template-columns: 1fr;
    }

    .story-shell,
    .inside-hero,
    .inside-layout {
        grid-template-columns: 1fr;
    }

    .story-intro,
    .inside-rail {
        position: static;
    }
}

@media (max-width: 920px) {
    .site-header {
        grid-template-columns: 1fr auto;
        gap: 12px 18px;
        padding-top: 10px;
        padding-bottom: 10px;
    }

    .site-nav {
        grid-column: 1 / -1;
        justify-content: flex-start;
        overflow-x: auto;
        white-space: nowrap;
        padding-bottom: 2px;
        scrollbar-width: none;
    }

    .site-nav::-webkit-scrollbar {
        display: none;
    }

    .chapter-rail-shell,
    .inside-rail-shell {
        overflow-x: auto;
        white-space: nowrap;
    }

    .story-section,
    .closing-section,
    .inside-hero,
    .inside-layout,
    .unlock-shell {
        padding-top: 72px;
        padding-bottom: 72px;
    }

    .row-item {
        grid-template-columns: 1fr;
        gap: 8px;
    }
}

@media (max-width: 640px) {
    .site-header,
    .hero-viewport,
    .chapter-rail,
    .story-section,
    .closing-section,
    .inside-hero,
    .inside-layout,
    .unlock-shell,
    .noscript-note {
        padding-inline: 16px;
    }

    .site-header {
        grid-template-columns: 1fr auto;
    }

    .brand-en {
        font-size: 13px;
    }

    .button {
        min-height: 40px;
        font-size: 16px;
    }

    .button-compact,
    .button-nav {
        min-height: 32px;
        font-size: 12px;
    }

    .hero-copy h1,
    .story-intro h2,
    .closing-shell h2,
    .inside-hero h1,
    .inside-section-head h2,
    .unlock-card h1 {
        font-size: clamp(2.4rem, 13vw, 3.7rem);
    }

    .hero-lead {
        font-size: 21px;
    }

    .hero-strap,
    .story-intro p,
    .closing-shell p,
    .inside-hero p,
    .inside-summary p,
    .inside-section-head p,
    .unlock-card p,
    .panel-block p,
    .bullet-list,
    .summary-list,
    .row-item dd {
        font-size: 16px;
    }

    .chapter-rail {
        top: var(--header-h);
        padding-top: 10px;
        padding-bottom: 10px;
    }

    .chapter-rail-shell {
        min-height: auto;
        gap: 14px;
    }

    .disclosure-panel summary,
    .internal-panel summary {
        grid-template-columns: 1fr;
        gap: 12px;
    }

    .panel-heading {
        padding-right: 34px;
    }

    .unlock-card {
        padding: 24px;
    }

    .unlock-form {
        grid-template-columns: 1fr;
    }

    .hero-stage {
        margin-top: 40px;
    }
}

@media (max-width: 480px) {
    .hero-actions,
    .closing-actions {
        justify-content: flex-start;
    }

    .header-actions {
        gap: 8px;
    }

    .site-nav {
        gap: 18px;
    }

    .rail-link {
        font-size: 13px;
    }
}