:root {
    --ink: #17211f;
    --muted: #5f6d69;
    --paper: #fbfaf7;
    --surface: #ffffff;
    --line: #d9dfdc;
    --teal: #087a70;
    --teal-dark: #055e57;
    --teal-soft: #e3f2ef;
    --rose: #b95765;
    --rose-soft: #f7e8eb;
    --charcoal: #20302c;
    --shadow: 0 18px 50px rgba(25, 49, 44, 0.12);
}

* {
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    margin: 0;
    color: var(--ink);
    background: var(--paper);
    font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "微软雅黑", Arial, Helvetica, sans-serif;
    line-height: 1.7;
}

body.menu-open {
    overflow: hidden;
}

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

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

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

.site-rail {
    width: min(1180px, calc(100% - 48px));
    margin: 0 auto;
}

.site-header {
    position: sticky;
    top: 0;
    z-index: 50;
    background: rgba(251, 250, 247, 0.96);
    border-bottom: 1px solid var(--line);
    backdrop-filter: blur(14px);
}

.header-inner {
    min-height: 72px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 32px;
}

.brand {
    display: inline-flex;
    align-items: center;
    gap: 12px;
    font-size: 20px;
    font-weight: 800;
}

.brand img {
    width: 42px;
    height: 42px;
    border-radius: 8px;
}

.site-nav {
    display: flex;
    align-items: center;
    gap: 30px;
    font-size: 15px;
    font-weight: 650;
}

.site-nav a {
    position: relative;
    padding: 8px 0;
}

.site-nav a:not(.nav-download)::after {
    content: "";
    position: absolute;
    right: 0;
    bottom: 0;
    left: 0;
    height: 2px;
    background: var(--teal);
    transform: scaleX(0);
    transform-origin: left;
    transition: transform 180ms ease;
}

.site-nav a:hover::after,
.site-nav a.active::after {
    transform: scaleX(1);
}

.site-nav .nav-download {
    min-width: 104px;
    padding: 10px 20px;
    color: #ffffff;
    text-align: center;
    background: var(--teal);
    border-radius: 6px;
}

.menu-toggle {
    display: none;
    width: 44px;
    height: 44px;
    padding: 0;
    color: var(--ink);
    background: transparent;
    border: 1px solid var(--line);
    border-radius: 6px;
    font-size: 22px;
    cursor: pointer;
}

.hero {
    overflow: hidden;
    background: linear-gradient(180deg, #fbfaf7 0%, #f2f5f2 100%);
    border-bottom: 1px solid var(--line);
}

.hero-grid {
    min-height: 602px;
    display: grid;
    grid-template-columns: minmax(0, 1.04fr) minmax(380px, 0.96fr);
    align-items: center;
    gap: 72px;
    padding: 54px 0 48px;
}

.eyebrow {
    display: inline-block;
    color: var(--teal-dark);
    font-size: 12px;
    font-weight: 800;
    letter-spacing: 0;
}

.hero h1,
.inner-hero h1 {
    max-width: 660px;
    margin: 14px 0 20px;
    font-size: clamp(40px, 5vw, 68px);
    line-height: 1.08;
    letter-spacing: 0;
}

.hero-copy > p {
    max-width: 600px;
    margin: 0;
    color: var(--muted);
    font-size: 18px;
}

.hero-actions {
    display: flex;
    align-items: center;
    gap: 24px;
    margin-top: 30px;
}

.primary-button {
    min-width: 136px;
    min-height: 48px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 12px 26px;
    color: #ffffff;
    background: var(--teal);
    border: 1px solid var(--teal);
    border-radius: 6px;
    font-weight: 750;
    transition: background 180ms ease, transform 180ms ease;
}

.primary-button:hover {
    background: var(--teal-dark);
    transform: translateY(-2px);
}

.text-link {
    color: var(--teal-dark);
    font-weight: 750;
}

.text-link span {
    display: inline-block;
    margin-left: 5px;
    transition: transform 180ms ease;
}

.text-link:hover span {
    transform: translateX(4px);
}

.hero-facts {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    margin: 36px 0 0;
    border-top: 1px solid var(--line);
}

.hero-facts div {
    padding: 18px 16px 0 0;
}

.hero-facts dt {
    color: var(--muted);
    font-size: 12px;
}

.hero-facts dd {
    margin: 3px 0 0;
    font-weight: 750;
}

.hero-media {
    position: relative;
    min-height: 476px;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 20px 24px 48px;
}

.screen-sheet {
    position: relative;
    z-index: 3;
    padding: 10px;
    background: #ffffff;
    border: 1px solid #cfd8d4;
    border-radius: 8px;
    box-shadow: var(--shadow);
}

.screen-sheet::before,
.screen-sheet::after {
    content: "";
    position: absolute;
    z-index: -1;
    width: 84%;
    height: 90%;
    top: 5%;
    background: var(--surface);
    border: 1px solid var(--line);
    border-radius: 8px;
}

.screen-sheet::before {
    right: -30px;
    transform: rotate(4deg);
}

.screen-sheet::after {
    left: -34px;
    transform: rotate(-5deg);
}

.screen-sheet img {
    width: auto;
    max-width: 400px;
    height: 394px;
    border-radius: 4px;
    object-fit: contain;
}

.paper-tab {
    position: absolute;
    z-index: 4;
    padding: 8px 14px;
    color: var(--charcoal);
    border-radius: 5px 5px 0 0;
    font-size: 13px;
    font-weight: 750;
}

.tab-one {
    top: 34px;
    left: 46px;
    background: var(--teal-soft);
}

.tab-two {
    top: 92px;
    right: 26px;
    background: var(--rose-soft);
}

.history-row {
    position: absolute;
    z-index: 5;
    right: 20px;
    bottom: 18px;
    left: 20px;
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 8px;
    padding: 12px;
    background: rgba(255, 255, 255, 0.96);
    border: 1px solid var(--line);
    border-radius: 6px;
    box-shadow: 0 10px 28px rgba(25, 49, 44, 0.1);
}

.history-row span {
    padding: 7px 8px;
    text-align: center;
    background: #f2f5f3;
    border-radius: 4px;
    color: var(--muted);
    font-size: 12px;
    font-weight: 700;
}

.filter-band {
    background: var(--surface);
    border-bottom: 1px solid var(--line);
}

.filter-layout {
    display: grid;
    grid-template-columns: 230px minmax(0, 1fr);
    gap: 60px;
    padding: 36px 0;
}

.section {
    padding: 88px 0;
}

.section-heading {
    display: flex;
    align-items: baseline;
    gap: 16px;
    margin-bottom: 42px;
}

.section-heading h2,
.deep-intro h2,
.download-inner h2 {
    margin: 0;
    font-size: 34px;
    line-height: 1.2;
    letter-spacing: 0;
}

.section-index {
    color: var(--rose);
    font-size: 13px;
    font-weight: 850;
}

.compact-heading {
    margin: 0;
}

.compact-heading h2 {
    font-size: 24px;
}

.definition-list {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    margin: 0;
}

.definition-list div {
    padding: 0 26px;
    border-left: 1px solid var(--line);
}

.definition-list dt {
    color: var(--teal-dark);
    font-weight: 800;
}

.definition-list dd {
    margin: 5px 0 0;
    color: var(--muted);
    font-size: 14px;
}

.preview-section {
    background: var(--paper);
}

.preview-grid {
    display: grid;
    grid-template-columns: 1.1fr 1fr 1fr;
    align-items: start;
    gap: 28px;
}

.preview-item {
    margin: 0;
    padding: 20px;
    background: var(--surface);
    border: 1px solid var(--line);
    border-radius: 6px;
}

.preview-item:nth-child(2) {
    margin-top: 44px;
}

.preview-item:nth-child(3) {
    margin-top: 88px;
}

.preview-item img {
    width: auto;
    max-width: 400px;
    height: 410px;
    margin: 0 auto;
    object-fit: contain;
}

.preview-item figcaption {
    display: grid;
    gap: 5px;
    margin-top: 18px;
    padding-top: 16px;
    border-top: 1px solid var(--line);
}

.preview-item figcaption span {
    color: var(--muted);
    font-size: 14px;
}

.functions-section {
    color: #ffffff;
    background: var(--charcoal);
}

.light-heading .section-index {
    color: #8bd1c8;
}

.feature-grid {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 0;
    border-top: 1px solid rgba(255, 255, 255, 0.18);
    border-left: 1px solid rgba(255, 255, 255, 0.18);
}

.feature-grid article {
    min-height: 220px;
    padding: 30px;
    border-right: 1px solid rgba(255, 255, 255, 0.18);
    border-bottom: 1px solid rgba(255, 255, 255, 0.18);
}

.feature-number {
    display: inline-flex;
    width: 34px;
    height: 34px;
    align-items: center;
    justify-content: center;
    color: var(--charcoal);
    background: #9ad8cf;
    border-radius: 4px;
    font-weight: 850;
}

.feature-grid h3 {
    margin: 24px 0 8px;
    font-size: 20px;
}

.feature-grid p {
    max-width: 470px;
    margin: 0;
    color: #cbd7d3;
}

.deep-links-section {
    background: #f0f3f1;
}

.deep-links-grid {
    display: grid;
    grid-template-columns: 0.9fr 1fr 1fr;
    gap: 24px;
    align-items: stretch;
}

.deep-intro {
    padding: 10px 24px 10px 0;
}

.deep-intro h2 {
    margin-top: 10px;
}

.deep-intro .deep-summary {
    margin: 20px 0 0;
    color: var(--muted);
}

.deep-link-card {
    min-height: 230px;
    display: flex;
    flex-direction: column;
    align-items: flex-start;
    justify-content: space-between;
    padding: 28px;
    background: var(--surface);
    border: 1px solid var(--line);
    border-radius: 6px;
    transition: border-color 180ms ease, transform 180ms ease;
}

.deep-link-card:hover {
    border-color: var(--teal);
    transform: translateY(-4px);
}

.deep-link-card > span:first-child {
    color: var(--teal-dark);
    font-size: 13px;
    font-weight: 800;
}

.deep-link-card strong {
    max-width: 290px;
    font-size: 23px;
    line-height: 1.4;
}

.deep-link-card > span:last-child {
    font-size: 24px;
}

.faq-preview-section {
    background: var(--surface);
}

.faq-preview-layout {
    display: grid;
    grid-template-columns: 300px minmax(0, 1fr);
    gap: 80px;
}

.faq-preview-list details,
.accordion-list details {
    border-top: 1px solid var(--line);
}

.faq-preview-list details:last-of-type,
.accordion-list details:last-child {
    border-bottom: 1px solid var(--line);
}

summary {
    position: relative;
    padding: 22px 48px 22px 0;
    font-weight: 750;
    cursor: pointer;
    list-style: none;
}

summary::-webkit-details-marker {
    display: none;
}

summary::after {
    content: "+";
    position: absolute;
    top: 17px;
    right: 5px;
    color: var(--teal-dark);
    font-size: 24px;
    font-weight: 500;
}

details[open] summary::after {
    content: "−";
}

.faq-preview-list details p,
.accordion-list details div {
    margin: 0;
    padding: 0 48px 22px 0;
    color: var(--muted);
}

.faq-preview-list .text-link {
    display: inline-block;
    margin-top: 28px;
}

.download-band {
    color: #ffffff;
    background: var(--teal-dark);
}

.download-inner {
    min-height: 190px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 30px;
}

.download-inner .eyebrow {
    color: #a8ddd7;
}

.download-inner h2 {
    margin-top: 8px;
}

.light-button {
    color: var(--teal-dark);
    background: #ffffff;
    border-color: #ffffff;
}

.light-button:hover {
    color: #ffffff;
    background: transparent;
}

.site-footer {
    color: #5b6864;
    background: #e9eeeb;
    border-top: 1px solid var(--line);
}

.footer-inner {
    min-height: 126px;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    text-align: center;
}

.footer-inner p {
    margin: 4px 0;
    font-size: 13px;
}

.inner-main {
    background: var(--surface);
}

.inner-hero {
    background: #eef3f0;
    border-bottom: 1px solid var(--line);
}

.inner-hero-grid {
    min-height: 480px;
    display: grid;
    grid-template-columns: minmax(0, 1fr) 420px;
    align-items: center;
    gap: 80px;
    padding: 64px 0;
}

.inner-hero h1 {
    font-size: clamp(38px, 4.8vw, 62px);
}

.inner-hero p {
    max-width: 650px;
    margin: 0 0 26px;
    color: var(--muted);
    font-size: 17px;
}

.step-map {
    margin: 0;
    padding: 0;
    list-style: none;
    background: var(--surface);
    border: 1px solid var(--line);
    border-radius: 6px;
}

.step-map li {
    display: flex;
    align-items: center;
    gap: 20px;
    padding: 17px 22px;
    border-bottom: 1px solid var(--line);
    font-weight: 700;
}

.step-map li:last-child {
    border-bottom: 0;
}

.step-map span {
    color: var(--rose);
    font-size: 12px;
    font-weight: 850;
}

.inner-section {
    padding: 86px 0;
}

.prose-layout {
    display: grid;
    grid-template-columns: 220px minmax(0, 760px);
    justify-content: center;
    gap: 70px;
}

.prose-index {
    position: sticky;
    top: 104px;
    align-self: start;
    display: grid;
    gap: 8px;
    padding: 22px;
    background: var(--paper);
    border: 1px solid var(--line);
    border-radius: 6px;
}

.prose-index strong {
    margin-bottom: 8px;
}

.prose-index a {
    color: var(--muted);
    font-size: 14px;
}

.prose-index a:hover {
    color: var(--teal-dark);
}

.prose-content section {
    margin-bottom: 72px;
    scroll-margin-top: 110px;
}

.prose-content h2,
.faq-category-heading h2,
.faq-next h2 {
    margin: 8px 0 20px;
    font-size: 32px;
    line-height: 1.3;
    letter-spacing: 0;
}

.prose-content p {
    margin: 0 0 18px;
    color: #3f4b48;
    font-size: 16px;
}

.prose-content a,
.faq-next a:not(.primary-button) {
    color: var(--teal-dark);
    font-weight: 750;
    text-decoration: underline;
    text-underline-offset: 3px;
}

.article-kicker {
    color: var(--rose);
    font-size: 12px;
    font-weight: 850;
}

.notice-box {
    display: grid;
    gap: 4px;
    margin-top: 28px;
    padding: 22px 24px;
    background: var(--teal-soft);
    border-left: 3px solid var(--teal);
}

.notice-box span {
    color: var(--muted);
}

.faq-hero-layout {
    min-height: 410px;
    display: grid;
    grid-template-columns: minmax(0, 1fr) 340px;
    align-items: center;
    gap: 80px;
    padding: 60px 0;
}

.issue-tags {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 10px;
}

.issue-tags a {
    min-height: 74px;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 14px;
    background: var(--surface);
    border: 1px solid var(--line);
    border-radius: 6px;
    font-weight: 750;
}

.issue-tags a:hover {
    border-color: var(--teal);
}

.faq-library {
    background: var(--paper);
}

.faq-library-layout {
    max-width: 940px;
}

.faq-category {
    display: grid;
    grid-template-columns: 210px minmax(0, 1fr);
    gap: 60px;
    padding: 60px 0;
    border-bottom: 1px solid var(--line);
    scroll-margin-top: 90px;
}

.faq-category:first-child {
    padding-top: 0;
}

.faq-category-heading span {
    color: var(--rose);
    font-size: 13px;
    font-weight: 850;
}

.faq-category-heading h2 {
    margin-top: 8px;
    font-size: 25px;
}

.accordion-list details div p {
    margin: 0;
}

.faq-next {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 40px;
    margin-top: 70px;
    padding: 38px;
    background: var(--surface);
    border: 1px solid var(--line);
    border-radius: 6px;
}

.faq-next h2 {
    font-size: 27px;
}

.faq-next p {
    max-width: 620px;
    margin: 0;
    color: var(--muted);
}

@media (max-width: 980px) {
    .hero-grid,
    .inner-hero-grid,
    .faq-hero-layout {
        grid-template-columns: minmax(0, 1fr) 360px;
        gap: 40px;
    }

    .hero h1,
    .inner-hero h1 {
        font-size: 46px;
    }

    .site-nav {
        gap: 18px;
    }

    .deep-links-grid {
        grid-template-columns: 1fr 1fr;
    }

    .deep-intro {
        grid-column: 1 / -1;
    }

    .faq-preview-layout {
        grid-template-columns: 240px minmax(0, 1fr);
        gap: 50px;
    }
}

@media (max-width: 760px) {
    .site-rail {
        width: min(100% - 32px, 620px);
    }

    .header-inner {
        min-height: 64px;
    }

    .menu-toggle {
        display: inline-flex;
        align-items: center;
        justify-content: center;
    }

    .site-nav {
        position: fixed;
        top: 64px;
        right: 0;
        left: 0;
        display: none;
        flex-direction: column;
        align-items: stretch;
        gap: 0;
        padding: 18px 16px 24px;
        background: var(--paper);
        border-bottom: 1px solid var(--line);
        box-shadow: 0 16px 30px rgba(25, 49, 44, 0.12);
    }

    .site-nav.open {
        display: flex;
    }

    .site-nav a {
        padding: 14px 12px;
        text-align: center;
    }

    .site-nav .nav-download {
        margin-top: 8px;
    }

    .hero-grid,
    .inner-hero-grid,
    .faq-hero-layout {
        min-height: 0;
        grid-template-columns: 1fr;
        gap: 30px;
        padding: 42px 0 36px;
    }

    .hero h1,
    .inner-hero h1 {
        margin-top: 10px;
        font-size: 38px;
    }

    .hero-copy > p,
    .inner-hero p {
        font-size: 16px;
    }

    .hero-actions {
        align-items: center;
        flex-direction: row;
        flex-wrap: wrap;
        gap: 14px 20px;
        margin-top: 24px;
    }

    .hero-facts {
        display: none;
    }

    .hero-facts div {
        padding-right: 8px;
    }

    .hero-media {
        min-height: 286px;
        padding: 8px 30px 44px;
    }

    .screen-sheet img {
        height: 238px;
    }

    .tab-one {
        top: 16px;
        left: 12px;
    }

    .tab-two {
        top: 56px;
        right: 4px;
    }

    .filter-layout,
    .faq-preview-layout,
    .prose-layout,
    .faq-category {
        grid-template-columns: 1fr;
        gap: 26px;
    }

    .filter-layout {
        padding: 32px 0;
    }

    .definition-list {
        grid-template-columns: 1fr;
    }

    .definition-list div {
        padding: 15px 0;
        border-top: 1px solid var(--line);
        border-left: 0;
    }

    .section,
    .inner-section {
        padding: 64px 0;
    }

    .section-heading {
        margin-bottom: 30px;
    }

    .section-heading h2,
    .deep-intro h2,
    .download-inner h2 {
        font-size: 29px;
    }

    .preview-grid,
    .feature-grid,
    .deep-links-grid {
        grid-template-columns: 1fr;
    }

    .preview-item:nth-child(2),
    .preview-item:nth-child(3) {
        margin-top: 0;
    }

    .preview-item img {
        height: 380px;
    }

    .feature-grid article {
        min-height: 0;
    }

    .deep-intro {
        grid-column: auto;
    }

    .faq-preview-layout .section-heading {
        margin-bottom: 0;
    }

    .download-inner,
    .faq-next {
        align-items: flex-start;
        flex-direction: column;
        justify-content: center;
        padding-top: 34px;
        padding-bottom: 34px;
    }

    .prose-index {
        position: static;
        grid-template-columns: repeat(2, minmax(0, 1fr));
    }

    .prose-index strong {
        grid-column: 1 / -1;
    }

    .prose-content section {
        margin-bottom: 58px;
    }

    .issue-tags {
        grid-template-columns: repeat(4, minmax(0, 1fr));
    }

    .issue-tags a {
        min-height: 64px;
        padding: 8px;
        font-size: 14px;
    }

    .faq-category {
        padding: 50px 0;
    }

    .faq-next {
        margin-top: 56px;
        padding-right: 24px;
        padding-left: 24px;
    }
}

@media (max-width: 420px) {
    .site-rail {
        width: calc(100% - 28px);
    }

    .brand {
        font-size: 18px;
    }

    .hero h1,
    .inner-hero h1 {
        font-size: 34px;
    }

    .hero-media {
        min-height: 276px;
        padding-right: 34px;
        padding-left: 34px;
    }

    .screen-sheet img {
        max-width: 100%;
        height: 228px;
    }

    .history-row {
        right: 0;
        left: 0;
    }

    .preview-item img {
        height: 360px;
    }

    .issue-tags {
        grid-template-columns: repeat(2, minmax(0, 1fr));
    }

    summary {
        padding-right: 38px;
    }

    .faq-preview-list details p,
    .accordion-list details div {
        padding-right: 18px;
    }
}