:root {
            --orange: #FF5500;
            --orange-ink: #A8390A;
            --blue: #155CC3;
            --ink: #182230;
            --muted: #475467;
            --line: #D5DFEB;
            --surface: #FCFDFF
        }
        
        *,
        *::before,
        *::after {
            box-sizing: border-box
        }
        
        html {
            scroll-padding-top: 94px
        }
        
        body {
            margin: 0;
            padding-top: 70px;
            background: #F7F9FC;
            color: var(--ink);
            font: 16px/1.9 system-ui, -apple-system, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
            overflow-wrap: anywhere
        }
        
        h1,
        h2,
        h3,
        p,
        ul,
        ol {
            margin: 0
        }
        
        a {
            color: inherit;
            text-decoration: none
        }
        
        button {
            font: inherit;
            color: inherit;
            cursor: pointer
        }
        
        svg {
            display: block;
            flex-shrink: 0;
            aspect-ratio: 1
        }
        
        :focus-visible {
            outline: 3px solid var(--blue);
            outline-offset: 4px;
            border-radius: 5px
        }
        
        [hidden] {
            display: none !important
        }
        
        .container {
            width: min(1200px, calc(100% - 64px));
            margin: auto
        }
        
        .svg-library {
            position: absolute;
            width: 0;
            height: 0;
            overflow: hidden
        }
        
        .skip-link {
            position: fixed;
            z-index: 100;
            top: 10px;
            left: 16px;
            padding: 10px 18px;
            background: #EDF3FD;
            transform: translateY(-160%)
        }
        
        .skip-link:focus {
            transform: none
        }
        
        .site-header {
            position: fixed;
            inset: 0 0 auto;
            z-index: 30;
            height: 70px;
            background: var(--surface);
            border-bottom: 1px solid var(--line)
        }
        
        .header-inner {
            display: flex;
            align-items: center;
            justify-content: space-between;
            gap: 24px;
            height: 70px
        }
        
        .brand-logo {
            display: inline-flex;
            align-items: center;
            gap: 10px;
            min-height: 44px;
            font-size: 22px;
            font-weight: 800;
            letter-spacing: -.8px;
            white-space: nowrap
        }
        
        .brand-logo svg {
            width: 40px;
            height: 40px
        }
        
        .main-navigation {
            display: flex;
            align-items: center;
            gap: 32px;
            height: 100%;
            font-size: 14px;
            font-weight: 650
        }
        
        .main-navigation a {
            position: relative;
            display: flex;
            align-items: center;
            min-height: 44px
        }
        
        .main-navigation [aria-current="page"] {
            font-weight: 800
        }
        
        .main-navigation [aria-current="page"]::after {
            content: "";
            position: absolute;
            bottom: 0;
            left: calc(50% - 9px);
            width: 18px;
            height: 3px;
            background: var(--orange);
            border-radius: 3px
        }
        
        .main-navigation a:hover,
        .brand-logo:hover,
        .footer-links-grid a:hover {
            color: var(--orange-ink)
        }
        
        .menu-toggle {
            display: none;
            place-items: center;
            width: 44px;
            height: 44px;
            padding: 0;
            border: 0;
            border-radius: 12px;
            background: #FFF1E9
        }
        
        .article-wrap {
            width: min(1200px, calc(100% - 64px));
            margin: 0 auto;
            padding: 30px 0 62px
        }
        
        .breadcrumb {
            display: flex;
            align-items: center;
            flex-wrap: wrap;
            gap: 8px;
            min-height: 44px;
            margin-bottom: 25px;
            font-size: 12px;
            color: var(--muted)
        }
        
        .breadcrumb a {
            display: inline-flex;
            align-items: center;
            min-height: 44px;
            color: var(--blue)
        }
        
        .article-sheet {
            padding: 35px 38px;
            background: var(--surface);
            border: 1px solid var(--line);
            border-radius: 22px
        }
        
        .article-category {
            font-size: 12px;
            font-weight: 750;
            color: var(--orange-ink);
            letter-spacing: 1px
        }
        
        .article-title {
            margin: 12px 0 17px;
            font-size: clamp(28px, 4vw, 37px);
            line-height: 1.45;
            font-weight: 850;
            letter-spacing: -1px
        }
        
        .article-meta {
            display: flex;
            flex-wrap: wrap;
            gap: 6px 20px;
            font-size: 12px;
            color: var(--muted)
        }
        
        .article-lead {
            margin-top: 21px;
            font-size: 16px
        }
        
        .article-body section {
            margin-top: 32px;
            scroll-margin-top: 94px
        }
        
        .article-body h2 {
            position: relative;
            padding-left: 16px;
            margin-bottom: 16px;
            font-size: 22px;
            line-height: 1.6
        }
        
        .article-body h2::before {
            content: "";
            position: absolute;
            inset: 5px auto 5px 0;
            width: 4px;
            background: var(--orange);
            border-radius: 3px
        }
        
        .article-body p+p {
            margin-top: 16px
        }
        
        .article-body a,
        .article-related a {
            color: var(--blue);
            text-decoration: underline;
            text-underline-offset: 4px
        }
        
        .article-note {
            padding: 16px 20px;
            margin-top: 28px;
            border-left: 3px solid var(--orange);
            background: #F3F6FA;
            border-radius: 0 10px 10px 0;
            font-size: 13px;
            color: var(--muted)
        }
        
        .article-related {
            display: flex;
            flex-wrap: wrap;
            gap: 6px 20px;
            margin-top: 28px;
            padding-top: 18px;
            border-top: 1px solid var(--line);
            font-size: 13px
        }
        
        .article-related a {
            display: inline-flex;
            align-items: center;
            min-height: 44px
        }
        
        .references {
            margin-top: 22px;
            padding: 14px 18px;
            border: 1px solid var(--line);
            border-radius: 12px;
            background: #F3F6FA;
            font-size: 12px;
            color: var(--muted)
        }
        
        .references summary {
            min-height: 32px;
            cursor: pointer;
            font-weight: 700
        }
        
        .references ul {
            padding-left: 18px
        }
        
        .references a {
            display: inline-flex;
            align-items: center;
            min-height: 36px;
            color: var(--blue);
            text-decoration: underline;
            text-underline-offset: 4px
        }
        
        .site-footer {
            padding: 42px 0 24px;
            border-top: 1px solid var(--line);
            background: #EDF2F7
        }
        
        .footer-top {
            display: grid;
            grid-template-columns: 1fr 1.25fr;
            gap: 65px;
            margin-bottom: 29px
        }
        
        .footer-brand>p {
            margin-top: 12px;
            color: var(--muted);
            font-size: 12px
        }
        
        .footer-links-grid {
            display: grid;
            grid-template-columns: repeat(3, minmax(0, 1fr));
            gap: 28px
        }
        
        .footer-links-grid h3 {
            margin-bottom: 9px;
            color: var(--orange-ink);
            font-size: 13px
        }
        
        .footer-links-grid a {
            display: flex;
            align-items: center;
            min-height: 40px;
            color: var(--muted);
            font-size: 12px
        }
        
        .footer-bottom {
            display: flex;
            align-items: center;
            justify-content: space-between;
            flex-wrap: wrap;
            gap: 10px 24px;
            border-top: 1px solid var(--line);
            padding-top: 18px;
            font-size: 11px;
            color: var(--muted)
        }
        
        .footer-domain {
            display: inline-flex;
            align-items: center;
            min-height: 28px;
            margin-left: auto;
            text-align: right;
            overflow-wrap: anywhere
        }
        
        .footer-domain:hover {
            color: var(--blue);
            text-decoration: underline
        }
        
        @media(max-width:900px) {
            .main-navigation {
                gap: 21px
            }
        
            .footer-top {
                gap: 35px
            }
        }
        
        @media(max-width:760px) {
            .container {
                width: calc(100% - 40px)
            }
        
            .article-wrap {
                width: calc(100% - 40px);
                padding: 22px 0 44px
            }
        
            .article-sheet {
                padding: 27px 25px
            }
        
            .brand-logo {
                font-size: 20px
            }
        
            .brand-logo svg {
                width: 36px;
                height: 36px
            }
        
            .menu-toggle {
                display: grid
            }
        
            .main-navigation {
                display: none;
                position: absolute;
                top: 70px;
                left: 0;
                right: 0;
                flex-direction: column;
                align-items: stretch;
                height: auto;
                padding: 16px 20px 22px;
                gap: 4px;
                background: var(--surface);
                border-bottom: 1px solid var(--line)
            }
        
            .main-navigation.is-open {
                display: flex
            }
        
            .main-navigation a {
                min-height: 46px;
                padding: 8px 14px
            }
        
            .main-navigation [aria-current="page"]::after {
                left: auto;
                right: 14px;
                bottom: 20px
            }
        
            .article-title {
                font-size: 29px
            }
        
            .article-body h2 {
                font-size: 21px
            }
        
            .footer-top {
                grid-template-columns: 1fr;
                gap: 28px
            }
        
            .footer-links-grid {
                gap: 18px
            }
        }
        
        @media(max-width:380px) {
        
            .container,
            .article-wrap {
                width: calc(100% - 32px)
            }
        
            .article-sheet {
                padding: 23px 19px
            }
        
            .article-title {
                font-size: 27px
            }
        
            .article-body h2 {
                font-size: 20px
            }
        
            .footer-links-grid {
                gap: 12px
            }
        
            .footer-links-grid a,
            .footer-links-grid h3 {
                font-size: 11px
            }
        }
        
        @media print {
            body {
                padding-top: 0;
                background: #F7F9FC
            }
        
            .site-header,
            .site-footer,
            .skip-link,
            .article-related {
                display: none
            }
        
            .article-wrap {
                width: 100%;
                padding: 0
            }
        
            .article-sheet {
                padding: 0;
                border: 0
            }
        
            .article-body section {
                break-inside: avoid
            }
        }
        
        /* Article detail: shared outer width with a centered reading column. */
        .article-wrap {
            padding: 24px 0 48px
        }
        
        .breadcrumb {
            margin-bottom: 16px
        }
        
        .article-sheet {
            display: grid;
            grid-template-columns: minmax(0, 1fr);
            grid-template-areas: "heading" "cover" "body" "links" "related";
            align-items: start;
            column-gap: 36px;
            row-gap: 28px;
            padding: 40px;
            border-radius: 22px
        }
        
        .article-header,
        .article-cover,
        .article-body,
        .article-related {
            width: 100%;
            justify-self: center
        }
        
        .article-header {
            grid-area: heading;
            min-width: 0
        }
        
        .article-title {
            margin: 12px 0 16px;
            font-size: clamp(28px, 2.7vw, 36px);
            line-height: 1.4;
            letter-spacing: -.8px;
            text-wrap: balance
        }
        
        .article-meta {
            gap: 6px 18px;
            font-size: 12px;
            line-height: 1.8
        }
        
        .article-lead {
            margin-top: 20px;
            font-size: 16px;
            line-height: 1.9;
            color: var(--muted)
        }
        
        .article-cover {
            grid-area: cover;
            width: 100%;
            margin: 0;
            border: 1px solid var(--line);
            border-radius: 14px;
            overflow: hidden;
            aspect-ratio: 16/9
        }
        
        
        
        
        
        
        .article-body {
            grid-area: body;
            min-width: 0;
            font-size: 16px;
            line-height: 1.95
        }
        
        .article-body section {
            margin-top: 32px;
            scroll-margin-top: 94px
        }
        
        .article-body section:first-child {
            margin-top: 0
        }
        
        .article-body h2 {
            margin-bottom: 14px;
            font-size: 22px;
            line-height: 1.5;
            text-wrap: balance
        }
        
        .article-body p+p {
            margin-top: 16px
        }
        
        .article-body li+li {
            margin-top: 10px
        }
        
        .article-body ul,
        .article-body ol {
            padding-left: 23px;
            margin-top: 16px
        }
        
        .article-body code {
            padding: 2px 7px;
            border-radius: 5px;
            background: #EDF3FD;
            color: #104A9F;
            font: 14px/1.6 ui-monospace, Consolas, monospace
        }
        
        .phrase-examples {
            display: grid;
            gap: 10px;
            margin: 20px 0
        }
        
        .phrase-example {
            display: grid;
            grid-template-columns: 70px minmax(0, 1fr);
            align-items: start;
            gap: 16px;
            padding: 16px 18px;
            border: 1px solid var(--line);
            border-radius: 12px;
            background: #F3F6FA
        }
        
        .phrase-example code {
            text-align: center
        }
        
        .phrase-example p {
            font-size: 15px;
            line-height: 1.85
        }
        
        .editorial-callout {
            margin-top: 20px;
            padding: 20px;
            border-left: 3px solid var(--orange);
            border-radius: 0 12px 12px 0;
            background: #FFF1E9;
            color: var(--ink)
        }
        
        .article-related {
            grid-area: links;
            gap: 6px 20px;
            min-width: 0;
            margin: 0;
            padding-top: 16px
        }
        
        .related-articles {
            grid-area: related;
            min-width: 0;
            margin: 0;
            padding-top: 28px;
            border-top: 1px solid var(--line);
            scroll-margin-top: 94px
        }
        
        .related-heading {
            display: flex;
            align-items: center;
            justify-content: space-between;
            gap: 20px;
            margin-bottom: 16px
        }
        
        .related-heading h2 {
            position: relative;
            padding-left: 16px;
            font-size: 22px;
            line-height: 1.5
        }
        
        .related-heading h2::before {
            content: "";
            position: absolute;
            left: 0;
            top: 5px;
            bottom: 5px;
            width: 4px;
            border-radius: 3px;
            background: var(--orange)
        }
        
        .related-heading>a {
            display: inline-flex;
            align-items: center;
            min-height: 44px;
            color: var(--orange-ink);
            font-size: 13px;
            font-weight: 700
        }
        
        .related-heading>a:hover {
            text-decoration: underline;
            text-underline-offset: 4px
        }
        
        .related-grid {
            display: grid;
            grid-template-columns: repeat(3, minmax(0, 1fr));
            gap: 16px;
            padding: 0;
            list-style: none
        }
        
        .related-card {
            display: flex;
            min-width: 0
        }
        
        .related-card>a {
            display: flex;
            flex-direction: column;
            gap: 12px;
            width: 100%;
            min-height: 242px;
            padding: 22px;
            border: 1px solid var(--line);
            border-radius: 14px;
            background: #F7F9FC;
            transition: transform .3s cubic-bezier(.4, 0, .2, 1), border-color .3s, box-shadow .3s
        }
        
        .related-card>a:hover {
            transform: translateY(-4px);
            border-color: #BBCDE5;
            box-shadow: 0 16px 32px -24px rgba(21, 92, 195, .22)
        }
        
        .related-tag {
            align-self: flex-start;
            padding: 3px 9px;
            border-radius: 6px;
            background: #FFF1E9;
            color: var(--orange-ink);
            font-size: 12px;
            font-weight: 650
        }
        
        .related-card:nth-child(2) .related-tag {
            background: #EDF3FD;
            color: #104A9F
        }
        
        .related-card h3 {
            font-size: 17px;
            line-height: 1.55
        }
        
        .related-card>a:hover h3 {
            color: var(--orange-ink)
        }
        
        .related-card p {
            font-size: 14px;
            line-height: 1.85;
            color: var(--muted)
        }
        
        .related-read {
            display: flex;
            align-items: center;
            gap: 8px;
            margin-top: auto;
            padding-top: 4px;
            color: var(--orange-ink);
            font-size: 13px;
            font-weight: 700
        }
        
        .related-read svg {
            width: 16px;
            height: 16px
        }
        
        @media(max-width:1100px) {
            .article-sheet {
                padding: 30px;
                column-gap: 26px
            }
        
            .related-card>a {
                padding: 20px
            }
        }
        
        @media(max-width:900px) {
            .article-sheet {
                grid-template-columns: minmax(0, 1fr);
                grid-template-areas: "heading" "cover" "body" "links" "related";
                gap: 26px
            }
        
            .related-grid {
                grid-template-columns: 1fr
            }
        
            .related-card>a {
                min-height: 0;
                padding: 22px
            }
        
            .related-read {
                min-height: 32px
            }
        }
        
        @media(max-width:760px) {
            .article-wrap {
                padding: 16px 0 32px
            }
        
            .breadcrumb {
                margin-bottom: 12px
            }
        
            .article-sheet {
                padding: 26px 24px;
                gap: 24px;
                border-radius: 18px
            }
        
            .article-title {
                font-size: 29px;
                line-height: 1.4;
                margin: 12px 0 14px
            }
        
            .article-lead {
                margin-top: 16px
            }
        
            .article-cover {
                border-radius: 12px
            }
        
            .article-body {
                line-height: 1.9
            }
        
            .article-body h2 {
                font-size: 21px
            }
        
            .article-body section {
                margin-top: 28px
            }
        
            .phrase-example {
                grid-template-columns: 60px minmax(0, 1fr);
                gap: 12px;
                padding: 14px
            }
        
            .related-articles {
                padding-top: 24px
            }
        
            .related-heading {
                margin-bottom: 14px;
                gap: 12px
            }
        
            .related-heading h2 {
                font-size: 21px
            }
        
            .related-card>a {
                padding: 20px;
                gap: 12px
            }
        }
        
        @media(max-width:380px) {
            .article-sheet {
                padding: 24px 20px
            }
        
            .article-title {
                font-size: 27px
            }
        
            .article-meta {
                gap: 4px 14px
            }
        
            .article-body h2 {
                font-size: 20px
            }
        
            .editorial-callout {
                padding: 16px
            }
        
            .related-card>a {
                padding: 18px
            }
        
            .related-card h3 {
                font-size: 17px
            }
        }
        
        @media(prefers-reduced-motion:reduce) {
            .related-card>a {
                transition: none
            }
        
            .related-card>a:hover {
                transform: none
            }
        }
        
        @media print {
            .article-sheet {
                display: block;
                padding: 0
            }
        
            .article-related,
            .related-articles {
                display: none
            }
        
            .article-cover {
                max-width: 600px;
                margin: 24px auto
            }
        
            .article-body {
                margin-top: 24px
            }
        }