/* ouyigai12 — Charcoal #27272A + Gold #EAB308 · editorial typography */
@import url('https://fonts.googleapis.com/css2?family=Libre+Baskerville:ital,wght@0,400;0,700;1,400&family=Inter:wght@400;500;600;700&display=swap');

:root {
    --charcoal: #27272A;
    --charcoal-light: #3F3F46;
    --gold: #EAB308;
    --gold-dark: #CA8A04;
    --cream: #FAFAF9;
    --paper: #FFFFFF;
    --muted: #71717A;
    --border: #E4E4E7;
    --header-h: 72px;
    --container: 1140px;
    --serif: "Libre Baskerville", Georgia, "Times New Roman", serif;
    --sans: "Inter", -apple-system, BlinkMacSystemFont, sans-serif;
}

*, *::before, *::after { margin: 0; padding: 0; box-sizing: border-box; }

body {
    font-family: var(--sans);
    font-size: 16px;
    line-height: 1.65;
    color: var(--charcoal);
    background: var(--cream);
    overflow-x: hidden;
}

img { max-width: 100%; height: auto; display: block; }
a { color: inherit; text-decoration: none; transition: color 0.2s; }
ul { list-style: none; }
button { border: none; background: none; cursor: pointer; font: inherit; }

.z454c7container { max-width: var(--container); margin: 0 auto; padding: 0 1.25rem; }

#features, #products, #guide, #security, #faq, #articles { scroll-margin-top: calc(var(--header-h) + 16px); }

/* Header */
.z454c7header {
    position: fixed;
    top: 0; left: 0; right: 0;
    z-index: 1000;
    background: var(--paper);
    border-bottom: 1px solid var(--border);
}

.z454c7header-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: var(--header-h);
    gap: 1rem;
}

.z454c7logo-kicker {
    font-size: 0.65rem;
    letter-spacing: 0.2em;
    text-transform: uppercase;
    color: var(--gold-dark);
    margin-bottom: 0.15rem;
}

.z454c7logo h1 {
    font-family: var(--serif);
    font-size: 1.35rem;
    font-weight: 700;
    line-height: 1.2;
}

.z454c7logo h1 a:hover { color: var(--gold-dark); }

.z454c7main-nav ul { display: flex; flex-wrap: wrap; gap: 0.15rem 1.25rem; align-items: center; }

.z454c7main-nav a {
    font-size: 0.82rem;
    font-weight: 500;
    letter-spacing: 0.02em;
    color: var(--charcoal);
    padding: 0.25rem 0;
    border-bottom: 1px solid transparent;
}

.z454c7main-nav a:hover { border-bottom-color: var(--gold); color: var(--charcoal); }

.z454c7main-nav li.z454c7this a { border-bottom-color: var(--gold); font-weight: 600; }

.z454c7menu-toggle {
    display: none;
    flex-direction: column;
    justify-content: center;
    gap: 5px;
    width: 36px;
    height: 36px;
    padding: 6px;
    border: 1px solid var(--border);
    border-radius: 4px;
}

.z454c7menu-toggle span { display: block; height: 2px; background: var(--charcoal); transition: 0.25s; }

/* Hero editorial */
.z454c7hero {
    padding: calc(var(--header-h) + 3rem) 0 4rem;
    background: var(--paper);
    border-bottom: 1px solid var(--border);
}

.z454c7hero-grid {
    display: grid;
    grid-template-columns: minmax(0, 1.1fr) minmax(280px, 0.9fr);
    gap: 3rem;
    align-items: center;
}

.z454c7hero-label {
    font-size: 0.7rem;
    letter-spacing: 0.18em;
    text-transform: uppercase;
    color: var(--muted);
    margin-bottom: 1rem;
}

.z454c7hero-headline {
    font-family: var(--serif);
    font-size: clamp(2rem, 5vw, 3.25rem);
    font-weight: 700;
    line-height: 1.12;
    letter-spacing: -0.02em;
    margin-bottom: 1.25rem;
}

.z454c7hero-dek {
    font-size: 1.1rem;
    color: var(--charcoal-light);
    line-height: 1.7;
    margin-bottom: 1rem;
    max-width: 540px;
}

.z454c7hero-intro {
    font-size: 0.92rem;
    color: var(--muted);
    line-height: 1.75;
    margin-bottom: 2rem;
    max-width: 560px;
    border-left: 3px solid var(--gold);
    padding-left: 1rem;
}

.z454c7hero-figure { margin: 0; }

.z454c7hero-figure figcaption {
    margin-top: 0.75rem;
    font-size: 0.75rem;
    font-style: italic;
    color: var(--muted);
    text-align: center;
}

.z454c7hero-img {
    border: 1px solid var(--border);
    border-radius: 2px;
    box-shadow: 8px 8px 0 var(--gold);
}

.z454c7keyword-band {
    padding: 0.85rem 0;
    background: var(--charcoal);
    color: rgba(255, 255, 255, 0.88);
    border-bottom: 1px solid var(--charcoal-light);
}

.z454c7keyword-band p {
    font-size: 0.78rem;
    line-height: 1.75;
    text-align: center;
}

.z454c7keyword-band strong { color: var(--gold); font-weight: 600; }

.z454c7guide-list a { color: var(--gold-dark); font-weight: 600; text-decoration: underline; text-underline-offset: 2px; }

.z454c7guide-list a:hover { color: var(--gold); }

.z454c7download-buttons { display: flex; flex-wrap: wrap; gap: 0.65rem; }

.z454c7btn {
    display: inline-block;
    padding: 0.65rem 1.35rem;
    font-size: 0.85rem;
    font-weight: 600;
    letter-spacing: 0.03em;
    border: 1px solid var(--charcoal);
    transition: 0.2s;
}

.z454c7btn-primary { background: var(--charcoal); color: var(--paper); }

.z454c7btn-primary:hover { background: var(--gold); border-color: var(--gold); color: var(--charcoal); }

.z454c7btn-secondary { background: transparent; color: var(--charcoal); }

.z454c7btn-secondary:hover { background: var(--charcoal); color: var(--paper); }

/* Section heads */
.z454c7section-head { margin-bottom: 2.5rem; max-width: 720px; }

.z454c7section-head--light .z454c7section-title,
.z454c7section-head--light .z454c7section-lead { color: var(--paper); }

.z454c7section-num {
    display: block;
    font-family: var(--serif);
    font-size: 0.85rem;
    font-style: italic;
    color: var(--gold-dark);
    margin-bottom: 0.5rem;
}

.z454c7section-title {
    font-family: var(--serif);
    font-size: clamp(1.75rem, 3.5vw, 2.5rem);
    font-weight: 700;
    line-height: 1.15;
    margin-bottom: 0.75rem;
}

.z454c7section-lead { font-size: 1rem; color: var(--muted); line-height: 1.7; }

/* Features editorial columns */
.z454c7features { padding: 4.5rem 0; background: var(--cream); border-bottom: 1px solid var(--border); }

.z454c7editorial-columns {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 1px;
    background: var(--border);
    border: 1px solid var(--border);
}

.z454c7editorial-block {
    background: var(--paper);
    padding: 2rem 1.75rem;
}

.z454c7editorial-block h3 {
    font-family: var(--serif);
    font-size: 1.25rem;
    margin-bottom: 0.75rem;
    padding-bottom: 0.5rem;
    border-bottom: 1px solid var(--border);
}

.z454c7editorial-block p { font-size: 0.92rem; color: var(--muted); margin-bottom: 1rem; line-height: 1.7; }

.z454c7editorial-block ul li {
    font-size: 0.85rem;
    padding: 0.35rem 0;
    border-bottom: 1px solid var(--border);
    color: var(--charcoal-light);
}

.z454c7editorial-block ul li:last-child { border-bottom: none; }

.z454c7editorial-block--highlight { background: var(--charcoal); color: var(--paper); }

.z454c7editorial-block--highlight h3 { color: var(--gold); border-bottom-color: rgba(255,255,255,0.15); }

.z454c7editorial-block--highlight p,
.z454c7editorial-block--highlight ul li { color: rgba(255,255,255,0.8); border-bottom-color: rgba(255,255,255,0.1); }

/* Products */
.z454c7products { padding: 4.5rem 0; background: var(--paper); border-bottom: 1px solid var(--border); }

.z454c7product-editorial {
    display: grid;
    grid-template-columns: minmax(0, 1.4fr) minmax(0, 1fr);
    gap: 1px;
    background: var(--border);
    border: 1px solid var(--border);
}

.z454c7product-lead {
    background: var(--charcoal);
    color: var(--paper);
    padding: 2.5rem 2rem;
}

.z454c7product-tag {
    display: inline-block;
    font-size: 0.7rem;
    letter-spacing: 0.12em;
    text-transform: uppercase;
    color: var(--gold);
    margin-bottom: 1rem;
}

.z454c7product-lead h3 {
    font-family: var(--serif);
    font-size: 1.75rem;
    margin-bottom: 1rem;
}

.z454c7product-lead p { color: rgba(255,255,255,0.82); margin-bottom: 1.25rem; line-height: 1.7; }

.z454c7product-lead ul li { font-size: 0.88rem; padding: 0.4rem 0; border-top: 1px solid rgba(255,255,255,0.12); }

.z454c7product-aside { display: flex; flex-direction: column; gap: 1px; background: var(--border); }

.z454c7product-mini {
    background: var(--paper);
    padding: 1.75rem;
    flex: 1;
}

.z454c7product-mini h3 { font-family: var(--serif); font-size: 1.1rem; margin-bottom: 0.5rem; }

.z454c7product-mini p { font-size: 0.88rem; color: var(--muted); line-height: 1.65; }

/* Guide */
.z454c7guide { padding: 4.5rem 0; background: var(--cream); border-bottom: 1px solid var(--border); }

.z454c7guide-list {
    counter-reset: guide;
    border-top: 1px solid var(--border);
}

.z454c7guide-list li {
    display: grid;
    grid-template-columns: minmax(140px, 200px) minmax(0, 1fr);
    gap: 1.5rem;
    padding: 1.5rem 0;
    border-bottom: 1px solid var(--border);
    align-items: baseline;
}

.z454c7guide-list li strong {
    font-family: var(--serif);
    font-size: 1.05rem;
    color: var(--charcoal);
}

.z454c7guide-list li strong::before {
    counter-increment: guide;
    content: counter(guide, decimal-leading-zero) " · ";
    color: var(--gold-dark);
    font-style: italic;
}

.z454c7guide-list li span { font-size: 0.92rem; color: var(--muted); line-height: 1.65; }

/* Security */
.z454c7security {
    padding: 4.5rem 0;
    background: var(--charcoal);
    border-bottom: 1px solid var(--charcoal-light);
}

.z454c7security-editorial {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 1px;
    background: rgba(255,255,255,0.08);
    border: 1px solid rgba(255,255,255,0.12);
}

.z454c7security-item {
    padding: 2rem 1.5rem;
    background: rgba(255,255,255,0.03);
}

.z454c7security-item h3 {
    font-family: var(--serif);
    font-size: 1.15rem;
    color: var(--gold);
    margin-bottom: 1rem;
    padding-bottom: 0.5rem;
    border-bottom: 1px solid rgba(255,255,255,0.1);
}

.z454c7security-item ul li {
    font-size: 0.88rem;
    color: rgba(255,255,255,0.78);
    padding: 0.35rem 0;
    border-bottom: 1px solid rgba(255,255,255,0.06);
}

/* FAQ */
.z454c7faq { padding: 4.5rem 0; background: var(--paper); border-bottom: 1px solid var(--border); }

.z454c7faq-editorial { border-top: 1px solid var(--border); }

.z454c7faq-details {
    border-bottom: 1px solid var(--border);
    padding: 0;
}

.z454c7faq-details summary {
    font-family: var(--serif);
    font-size: 1.05rem;
    font-weight: 700;
    padding: 1.25rem 0;
    cursor: pointer;
    list-style: none;
}

.z454c7faq-details summary::-webkit-details-marker { display: none; }

.z454c7faq-details summary::after { content: "+"; float: right; color: var(--gold-dark); font-family: var(--sans); }

.z454c7faq-details[open] summary::after { content: "−"; }

.z454c7faq-details p {
    font-size: 0.92rem;
    color: var(--muted);
    line-height: 1.75;
    padding-bottom: 1.25rem;
    max-width: 680px;
}

/* Articles editorial grid */
.z454c7articles { padding: 4.5rem 0; background: var(--cream); }

.z454c7article-editorial {
    display: grid;
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 1px;
    background: var(--border);
    border: 1px solid var(--border);
}

.z454c7article-card { background: var(--paper); display: flex; flex-direction: column; }

.z454c7article-card:first-child { grid-column: span 2; grid-row: span 2; }

.z454c7article-thumb {
    display: block;
    aspect-ratio: 16 / 10;
    overflow: hidden;
    border-bottom: 1px solid var(--border);
}

.z454c7article-card:first-child .z454c7article-thumb { aspect-ratio: 4 / 3; }

.z454c7article-thumb img { width: 100%; height: 100%; object-fit: cover; transition: transform 0.35s; }

.z454c7article-card:hover .z454c7article-thumb img { transform: scale(1.04); }

.z454c7article-card-body { padding: 1rem 1.15rem 1.25rem; flex: 1; }

.z454c7article-card-body time { font-size: 0.72rem; letter-spacing: 0.06em; text-transform: uppercase; color: var(--muted); }

.z454c7article-card-body h3 {
    font-family: var(--serif);
    font-size: 0.95rem;
    line-height: 1.45;
    margin-top: 0.35rem;
    display: -webkit-box;
    -webkit-line-clamp: 3;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.z454c7article-card-body h3 a:hover { color: var(--gold-dark); }

/* Footer */
.z454c7footer {
    background: var(--charcoal);
    color: rgba(255,255,255,0.8);
    padding: 3rem 0 1.5rem;
}

.z454c7footer-content {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 2rem;
    margin-bottom: 2rem;
    padding-bottom: 2rem;
    border-bottom: 1px solid rgba(255,255,255,0.1);
}

.z454c7footer-section h3 {
    font-family: var(--serif);
    font-size: 1rem;
    color: var(--gold);
    margin-bottom: 1rem;
}

.z454c7footer-section p { font-size: 0.88rem; line-height: 1.7; color: rgba(255,255,255,0.65); }

.z454c7footer-links li { margin-bottom: 0.4rem; }

.z454c7footer-links a { font-size: 0.85rem; color: rgba(255,255,255,0.6); }

.z454c7footer-links a:hover { color: var(--gold); }

.z454c7footer-bottom { text-align: center; }

.z454c7footer-bottom p { font-size: 0.8rem; color: rgba(255,255,255,0.45); margin: 0.3rem 0; }

.z454c7footer-bottom a { color: var(--gold); }

/* Inner pages */
.z454c7page-main {
    padding: calc(var(--header-h) + 2rem) 0 4rem;
    min-height: 60vh;
}

.z454c7breadcrumb {
    font-size: 0.82rem;
    color: var(--muted);
    margin-bottom: 2rem;
    padding-bottom: 1rem;
    border-bottom: 1px solid var(--border);
}

.z454c7breadcrumb a { color: var(--charcoal); border-bottom: 1px solid transparent; }

.z454c7breadcrumb a:hover { border-bottom-color: var(--gold); }

.z454c7breadcrumb-sep { margin: 0 0.5rem; color: var(--border); }

.z454c7page-layout {
    display: grid;
    grid-template-columns: minmax(0, 1fr) minmax(240px, 300px);
    gap: 2rem;
    align-items: start;
}

.z454c7page-content,
.z454c7listbox {
    background: var(--paper);
    border: 1px solid var(--border);
    padding: 2rem;
}

.z454c7page-title {
    font-family: var(--serif);
    font-size: 1.75rem;
    margin-bottom: 1rem;
    padding-bottom: 0.75rem;
    border-bottom: 2px solid var(--gold);
}

.z454c7list-lead { font-size: 0.9rem; color: var(--muted); line-height: 1.7; margin-bottom: 1.5rem; }

.z454c7list-item {
    display: grid;
    grid-template-columns: minmax(160px, 200px) minmax(0, 1fr);
    gap: 1.25rem;
    padding: 1.25rem 0;
    border-bottom: 1px solid var(--border);
    align-items: start;
}

.z454c7list-item:last-child { border-bottom: none; }

.z454c7list-thumb {
    aspect-ratio: 16 / 10;
    overflow: hidden;
    border: 1px solid var(--border);
}

.z454c7list-thumb img { width: 100%; height: 100%; object-fit: cover; }

.z454c7list-title {
    font-family: var(--serif);
    font-size: 1.05rem;
    color: var(--charcoal);
    display: block;
    margin-bottom: 0.5rem;
}

.z454c7list-title:hover { color: var(--gold-dark); }

.z454c7list-meta { font-size: 0.78rem; color: var(--muted); display: flex; gap: 1rem; }

.z454c7pagebar { margin-top: 1.5rem; }

.z454c7pages {
    display: flex;
    flex-wrap: wrap;
    justify-content: space-between;
    gap: 1rem;
    padding: 1rem;
    background: var(--paper);
    border: 1px solid var(--border);
}

.z454c7pagelist { display: flex; flex-wrap: wrap; gap: 0.35rem; list-style: none; }

.z454c7pagelist a,
.z454c7pagelist span {
    display: inline-block;
    padding: 0.4rem 0.75rem;
    font-size: 0.82rem;
    border: 1px solid var(--border);
    color: var(--charcoal);
}

.z454c7pagelist a:hover,
.z454c7pagelist .thisclass a {
    background: var(--charcoal);
    color: var(--paper);
    border-color: var(--charcoal);
}

.z454c7sidebar-block {
    background: var(--paper);
    border: 1px solid var(--border);
    overflow: hidden;
}

.z454c7sidebar-title {
    font-family: var(--serif);
    font-size: 0.95rem;
    padding: 1rem 1.15rem;
    background: var(--charcoal);
    color: var(--gold);
    border-bottom: 1px solid var(--charcoal-light);
}

.z454c7sidebar-thumb-list { padding: 0.5rem 0; max-height: 640px; overflow-y: auto; }

.z454c7sidebar-thumb-link {
    display: flex;
    gap: 0.75rem;
    padding: 0.65rem 1rem;
    border-bottom: 1px solid var(--border);
    align-items: center;
}

.z454c7sidebar-thumb-link:hover { background: var(--cream); }

.z454c7sidebar-thumb-img {
    flex: 0 0 72px;
    aspect-ratio: 3 / 2;
    overflow: hidden;
    border: 1px solid var(--border);
}

.z454c7sidebar-thumb-img img { width: 100%; height: 100%; object-fit: cover; }

.z454c7sidebar-thumb-title {
    flex: 1;
    font-size: 0.82rem;
    line-height: 1.45;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.z454c7article-header { margin-bottom: 1.5rem; padding-bottom: 1rem; border-bottom: 1px solid var(--border); }

.z454c7article-title {
    font-family: var(--serif);
    font-size: clamp(1.5rem, 3vw, 2rem);
    line-height: 1.25;
    margin-bottom: 0.75rem;
}

.z454c7article-meta {
    display: flex;
    flex-wrap: wrap;
    gap: 0.75rem 1.25rem;
    font-size: 0.82rem;
    color: var(--muted);
}

.z454c7article-meta a { color: var(--gold-dark); border-bottom: 1px solid transparent; }

.z454c7article-meta a:hover { border-bottom-color: var(--gold); }

.z454c7article-body {
    font-size: 1.02rem;
    line-height: 1.85;
    color: var(--charcoal-light);
}

.z454c7article-body img { max-width: 100%; border: 1px solid var(--border); margin: 1rem 0; }

.z454c7article-body p { margin-bottom: 1.15rem; }

.z454c7article-nav {
    display: flex;
    justify-content: space-between;
    gap: 1rem;
    margin-top: 2rem;
    padding-top: 1.25rem;
    border-top: 1px solid var(--border);
    font-size: 0.88rem;
}

.z454c7article-next { text-align: right; }

.z454c7nav-overlay {
    display: none;
    position: fixed;
    inset: 0;
    background: rgba(39, 39, 42, 0.5);
    z-index: 998;
}

.z454c7nav-overlay.active { display: block; }

/* Responsive */
@media (max-width: 992px) {
    .z454c7hero-grid { grid-template-columns: 1fr; }
    .z454c7product-editorial { grid-template-columns: 1fr; }
    .z454c7security-editorial { grid-template-columns: 1fr; }
    .z454c7article-editorial { grid-template-columns: repeat(2, minmax(0, 1fr)); }
    .z454c7article-card:first-child { grid-column: span 2; grid-row: span 1; }
    .z454c7page-layout { grid-template-columns: 1fr; }
}

@media (max-width: 768px) {
    :root { --header-h: 60px; }

    .z454c7menu-toggle { display: flex; }

    .z454c7main-nav {
        position: fixed;
        top: 0; right: -100%;
        width: min(300px, 85vw);
        height: 100vh;
        background: var(--paper);
        padding: calc(var(--header-h) + 1rem) 1.25rem 2rem;
        border-left: 1px solid var(--border);
        transition: right 0.3s;
        z-index: 999;
        overflow-y: auto;
    }

    .z454c7main-nav.active { right: 0; }

    .z454c7main-nav ul { flex-direction: column; align-items: flex-start; gap: 0; }

    .z454c7main-nav li { width: 100%; border-bottom: 1px solid var(--border); }

    .z454c7main-nav a { display: block; padding: 0.85rem 0; width: 100%; }

    .z454c7menu-toggle.active span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
    .z454c7menu-toggle.active span:nth-child(2) { opacity: 0; }
    .z454c7menu-toggle.active span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

    .z454c7editorial-columns { grid-template-columns: 1fr; }
    .z454c7guide-list li { grid-template-columns: 1fr; gap: 0.35rem; }
    .z454c7article-editorial { grid-template-columns: 1fr; }
    .z454c7article-card:first-child { grid-column: span 1; }
    .z454c7list-item { grid-template-columns: 1fr; }
    .z454c7footer-content { grid-template-columns: 1fr; }
    .z454c7pages { flex-direction: column; }
    .z454c7article-nav { flex-direction: column; }
    .z454c7article-next { text-align: left; }
}

@media (max-width: 480px) {
    .z454c7download-buttons { flex-direction: column; }
    .z454c7btn { text-align: center; }
}