:root {
    --page-bg: #ffffff;
    --section-bg: #f5f5f7;
    --card-bg: #ffffff;
    --nav-bg: rgba(251, 251, 253, 0.88);
    --footer-bg: #f5f5f7;
    --text-primary: #1d1d1f;
    --text-secondary: #6e6e73;
    --text-tertiary: #86868b;
    --text-link: #0071e3;
    --blue: #0071e3;
    --blue-hover: #0077ed;
    --blue-active: #006edb;
    --blue-ring: rgba(0, 113, 227, 0.16);
    --border-subtle: #d2d2d7;
    --border-soft: #e8e8ed;
    --shadow-sm: 0 2px 12px rgba(0, 0, 0, 0.04);
    --shadow-md: 0 4px 24px rgba(0, 0, 0, 0.06);
    --radius-pill: 980px;
    --radius-card: 18px;
    --radius-field: 10px;
    --nav-height: 52px;
    --content-max: 1068px;
    --article-max: 760px;
    --font-stack: -apple-system, BlinkMacSystemFont, "SF Pro Display", "SF Pro Text", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
}

@media (prefers-color-scheme: dark) {
    :root {
        --page-bg: #000000;
        --section-bg: #1c1c1e;
        --card-bg: #1c1c1e;
        --nav-bg: rgba(29, 29, 31, 0.88);
        --footer-bg: #1c1c1e;
        --text-primary: #f5f5f7;
        --text-secondary: #98989d;
        --text-tertiary: #6e6e73;
        --text-link: #2997ff;
        --blue: #0071e3;
        --blue-hover: #2997ff;
        --blue-active: #0077ed;
        --blue-ring: rgba(41, 151, 255, 0.24);
        --border-subtle: #424245;
        --border-soft: #38383a;
        --shadow-sm: 0 2px 12px rgba(0, 0, 0, 0.3);
        --shadow-md: 0 4px 24px rgba(0, 0, 0, 0.4);
    }
}

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

html {
    scroll-behavior: smooth;
    -webkit-text-size-adjust: 100%;
}

body {
    margin: 0;
    color: var(--text-primary);
    background: var(--page-bg);
    font-family: var(--font-stack);
    font-size: 17px;
    line-height: 1.65;
    letter-spacing: -0.012em;
    -webkit-font-smoothing: antialiased;
    text-rendering: optimizeLegibility;
}

body.menu-open {
    overflow: hidden;
}

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

a {
    color: var(--text-link);
    text-decoration-thickness: 1px;
    text-underline-offset: 0.2em;
}

a:hover {
    text-decoration: underline;
}

button {
    font: inherit;
}

h1,
h2,
h3 {
    margin: 0;
    color: var(--text-primary);
    font-weight: 650;
    line-height: 1.15;
    letter-spacing: -0.025em;
}

h1 {
    max-width: 900px;
    font-size: clamp(2.35rem, 7vw, 4.6rem);
}

h2 {
    margin-top: 2.7rem;
    font-size: clamp(1.65rem, 3.5vw, 2.25rem);
}

h3 {
    margin-top: 1.65rem;
    font-size: 1.2rem;
}

p,
ul,
ol,
dl,
table,
figure {
    margin: 1rem 0 0;
}

li + li {
    margin-top: 0.52rem;
}

code,
kbd {
    border: 1px solid var(--border-soft);
    border-radius: 6px;
    background: var(--section-bg);
    padding: 0.1em 0.35em;
    color: var(--text-primary);
    font-family: "SFMono-Regular", Consolas, "Liberation Mono", monospace;
    font-size: 0.88em;
}

.container {
    width: min(100% - 40px, var(--content-max));
    margin-inline: auto;
}

.skip-link {
    position: fixed;
    top: -100px;
    left: 16px;
    z-index: 300;
    border-radius: var(--radius-pill);
    background: var(--blue);
    padding: 8px 16px;
    color: #ffffff;
    font-size: 0.875rem;
}

.skip-link:focus {
    top: 8px;
}

.site-header {
    position: sticky;
    top: 0;
    z-index: 100;
    border-bottom: 1px solid var(--border-soft);
    background: var(--nav-bg);
    backdrop-filter: saturate(180%) blur(20px);
    -webkit-backdrop-filter: saturate(180%) blur(20px);
}

.site-nav {
    min-height: var(--nav-height);
    display: flex;
    align-items: center;
    gap: 28px;
}

.brand {
    display: inline-flex;
    flex: 0 0 auto;
    align-items: center;
    gap: 9px;
    color: var(--text-primary);
    font-size: 0.92rem;
    font-weight: 650;
}

.brand:hover {
    text-decoration: none;
}

.brand img {
    width: 28px;
    height: 28px;
    border-radius: 7px;
}

.nav-links {
    display: flex;
    flex: 1;
    align-items: center;
    justify-content: center;
    gap: 26px;
}

.nav-links a {
    color: var(--text-secondary);
    font-size: 0.86rem;
}

.nav-links a[aria-current="page"],
.nav-links a:hover {
    color: var(--text-primary);
    text-decoration: none;
}

.nav-cta,
.button {
    display: inline-flex;
    min-height: 42px;
    align-items: center;
    justify-content: center;
    border: 1px solid transparent;
    border-radius: var(--radius-pill);
    padding: 9px 18px;
    background: var(--blue);
    color: #ffffff;
    font-size: 0.92rem;
    font-weight: 600;
    line-height: 1.2;
}

.nav-cta {
    min-height: 34px;
    padding: 6px 14px;
    font-size: 0.82rem;
}

.nav-cta:hover,
.button:hover {
    background: var(--blue-hover);
    color: #ffffff;
    text-decoration: none;
}

.button-secondary {
    border-color: var(--border-subtle);
    background: transparent;
    color: var(--text-primary);
}

.button-secondary:hover {
    border-color: var(--text-primary);
    background: var(--section-bg);
    color: var(--text-primary);
}

.nav-toggle {
    display: none;
    width: 40px;
    height: 40px;
    align-items: center;
    justify-content: center;
    border: 0;
    border-radius: 50%;
    background: transparent;
    color: var(--text-primary);
    cursor: pointer;
}

.nav-toggle span,
.nav-toggle::before,
.nav-toggle::after {
    content: "";
    position: absolute;
    width: 18px;
    height: 1.5px;
    border-radius: 2px;
    background: currentColor;
    transition: transform 180ms ease, opacity 180ms ease;
}

.nav-toggle::before {
    transform: translateY(-5px);
}

.nav-toggle::after {
    transform: translateY(5px);
}

.nav-toggle[aria-expanded="true"] span {
    opacity: 0;
}

.nav-toggle[aria-expanded="true"]::before {
    transform: rotate(45deg);
}

.nav-toggle[aria-expanded="true"]::after {
    transform: rotate(-45deg);
}

.breadcrumbs {
    padding-top: 24px;
    color: var(--text-tertiary);
    font-size: 0.82rem;
}

.breadcrumbs ol {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin: 0;
    padding: 0;
    list-style: none;
}

.breadcrumbs li:not(:last-child)::after {
    content: "/";
    margin-left: 8px;
    color: var(--border-subtle);
}

.breadcrumbs a {
    color: var(--text-secondary);
}

.page-hero {
    padding: clamp(64px, 10vw, 112px) 0 clamp(54px, 8vw, 88px);
}

.eyebrow {
    margin: 0 0 16px;
    color: var(--blue);
    font-size: 0.9rem;
    font-weight: 650;
    letter-spacing: 0.08em;
    text-transform: uppercase;
}

.lead {
    max-width: 790px;
    margin-top: 24px;
    color: var(--text-secondary);
    font-size: clamp(1.12rem, 2.4vw, 1.42rem);
    line-height: 1.55;
}

.hero-actions {
    display: flex;
    flex-wrap: wrap;
    gap: 12px;
    margin-top: 28px;
}

.page-meta,
.article-meta {
    display: flex;
    flex-wrap: wrap;
    gap: 8px 18px;
    margin-top: 24px;
    color: var(--text-tertiary);
    font-size: 0.82rem;
}

.section {
    padding: 70px 0;
}

.section-alt {
    background: var(--section-bg);
}

.article-layout {
    display: grid;
    grid-template-columns: minmax(0, 1fr) 260px;
    gap: 68px;
    align-items: start;
}

.article-body {
    min-width: 0;
    max-width: var(--article-max);
}

.article-body > :first-child {
    margin-top: 0;
}

.article-body p,
.article-body li {
    color: var(--text-secondary);
}

.article-body strong {
    color: var(--text-primary);
}

.on-this-page {
    position: sticky;
    top: calc(var(--nav-height) + 28px);
    border-left: 1px solid var(--border-soft);
    padding-left: 20px;
}

.on-this-page strong {
    display: block;
    margin-bottom: 10px;
    font-size: 0.82rem;
}

.on-this-page a {
    display: block;
    padding: 5px 0;
    color: var(--text-secondary);
    font-size: 0.82rem;
    line-height: 1.4;
}

.grid {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 18px;
    margin-top: 30px;
}

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

.card,
.callout,
.faq-item {
    border: 1px solid var(--border-soft);
    border-radius: var(--radius-card);
    background: var(--card-bg);
    box-shadow: var(--shadow-sm);
}

.card {
    display: flex;
    min-height: 100%;
    flex-direction: column;
    padding: 26px;
}

.card h2,
.card h3 {
    margin-top: 0;
    font-size: 1.2rem;
}

.card p {
    flex: 1;
    color: var(--text-secondary);
    font-size: 0.96rem;
}

.card-link {
    margin-top: 18px;
    font-size: 0.92rem;
    font-weight: 600;
}

.tag-list {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin-top: 16px;
}

.tag {
    border-radius: var(--radius-pill);
    background: var(--section-bg);
    padding: 4px 10px;
    color: var(--text-secondary);
    font-size: 0.78rem;
}

.callout {
    margin-top: 28px;
    padding: 24px;
    border-left: 4px solid var(--blue);
}

.callout h2,
.callout h3,
.callout p:first-child {
    margin-top: 0;
}

.steps {
    padding-left: 1.4rem;
}

.steps li {
    padding-left: 0.35rem;
}

.feature-shot {
    overflow: hidden;
    margin-top: 28px;
    border: 1px solid var(--border-soft);
    border-radius: var(--radius-card);
    background: var(--section-bg);
    box-shadow: var(--shadow-md);
}

.feature-shot img,
.feature-shot video {
    width: 100%;
    height: auto;
}

.feature-shot.feature-shot-compact {
    width: fit-content;
    max-width: 100%;
}

.feature-shot.feature-shot-compact img {
    width: auto;
    max-width: 100%;
}

.feature-shot figcaption {
    margin: 0;
    padding: 12px 16px;
    color: var(--text-secondary);
    font-size: 0.82rem;
}

.table-wrap {
    overflow-x: auto;
    margin-top: 24px;
    border: 1px solid var(--border-soft);
    border-radius: var(--radius-card);
}

table {
    width: 100%;
    margin: 0;
    border-collapse: collapse;
    min-width: 620px;
    background: var(--card-bg);
}

th,
td {
    padding: 14px 16px;
    border-bottom: 1px solid var(--border-soft);
    text-align: left;
    vertical-align: top;
}

th {
    background: var(--section-bg);
    font-size: 0.86rem;
}

td {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

tr:last-child td {
    border-bottom: 0;
}

.faq-list {
    display: grid;
    gap: 16px;
    margin-top: 32px;
}

.faq-item {
    padding: 24px;
}

.faq-item h2 {
    margin-top: 0;
    font-size: 1.13rem;
    line-height: 1.35;
}

.faq-item p {
    color: var(--text-secondary);
}

.contact-grid {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 24px;
    margin-top: 28px;
}

.qr-card img {
    width: 168px;
    height: 168px;
    margin-top: 16px;
    border-radius: 12px;
}

.cta-band {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 28px;
    margin-top: 64px;
    border-radius: var(--radius-card);
    background: var(--section-bg);
    padding: 34px;
}

.cta-band h2 {
    margin-top: 0;
    font-size: 1.6rem;
}

.cta-band p {
    color: var(--text-secondary);
}

.site-footer {
    margin-top: 72px;
    border-top: 1px solid var(--border-soft);
    background: var(--footer-bg);
    padding: 36px 0;
    color: var(--text-secondary);
    font-size: 0.82rem;
}

.footer-grid {
    display: grid;
    grid-template-columns: 1.4fr repeat(3, 1fr);
    gap: 28px;
}

.footer-grid strong {
    display: block;
    margin-bottom: 10px;
    color: var(--text-primary);
}

.footer-grid a {
    display: block;
    width: fit-content;
    padding: 3px 0;
    color: var(--text-secondary);
}

.footer-bottom {
    display: flex;
    flex-wrap: wrap;
    gap: 8px 18px;
    margin-top: 28px;
    border-top: 1px solid var(--border-soft);
    padding-top: 20px;
}

:focus-visible {
    outline: 3px solid var(--blue-ring);
    outline-offset: 3px;
}

@media (max-width: 900px) {
    .nav-toggle {
        position: relative;
        display: inline-flex;
        margin-left: auto;
    }

    .nav-cta {
        margin-left: auto;
    }

    .nav-links {
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        display: none;
        align-items: stretch;
        gap: 0;
        border-bottom: 1px solid var(--border-soft);
        background: var(--page-bg);
        padding: 12px 20px 22px;
        box-shadow: var(--shadow-md);
    }

    .nav-links.open {
        display: grid;
    }

    .nav-links a {
        border-bottom: 1px solid var(--border-soft);
        padding: 12px 2px;
        font-size: 1rem;
    }

    .article-layout {
        grid-template-columns: 1fr;
        gap: 36px;
    }

    .on-this-page {
        position: static;
        order: -1;
        border-left: 0;
        border-radius: var(--radius-card);
        background: var(--section-bg);
        padding: 18px 20px;
    }

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

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

@media (max-width: 640px) {
    .container {
        width: min(100% - 32px, var(--content-max));
    }

    .brand span {
        display: none;
    }

    .nav-cta {
        display: none;
    }

    .page-hero {
        padding-top: 52px;
    }

    .grid,
    .grid-2,
    .contact-grid,
    .footer-grid {
        grid-template-columns: 1fr;
    }

    .section {
        padding: 52px 0;
    }

    .cta-band {
        align-items: flex-start;
        flex-direction: column;
        padding: 26px;
    }

    .button {
        width: 100%;
    }
}

@media (prefers-reduced-motion: reduce) {
    html {
        scroll-behavior: auto;
    }

    *,
    *::before,
    *::after {
        scroll-behavior: auto !important;
        transition-duration: 0.01ms !important;
    }
}

@media print {
    .site-header,
    .on-this-page,
    .hero-actions,
    .cta-band,
    .site-footer {
        display: none;
    }

    body {
        background: #ffffff;
        color: #000000;
    }

    .page-hero,
    .section {
        padding: 24px 0;
    }
}