:root {
    --canvas: #f7f7f4;
    --canvas-soft: #fafaf7;
    --surface-card: #ffffff;
    --surface-strong: #e6e5e0;
    --primary: #f54e00;
    --primary-active: #d04200;
    --ink: #26251e;
    --body: #5a5852;
    --body-strong: #26251e;
    --muted: #807d72;
    --muted-soft: #a09c92;
    --on-primary: #ffffff;
    --hairline: #e6e5e0;
    --hairline-soft: #efeee8;
    --hairline-strong: #cfcdc4;
    --success: #1f8a65;
    --error: #cf2d56;
    --radius-xs: 4px;
    --radius-sm: 6px;
    --radius-md: 8px;
    --radius-lg: 12px;
    --radius-xl: 16px;
    --radius-pill: 9999px;
    --section: 80px;
    --font-sans: 'Inter', system-ui, 'Helvetica Neue', Helvetica, Arial, sans-serif;
    --font-mono: 'JetBrains Mono', monospace;
}

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

html { scroll-behavior: smooth; }

body {
    background: var(--canvas);
    color: var(--body);
    font-family: var(--font-sans);
    font-size: 16px;
    line-height: 1.5;
    -webkit-font-smoothing: antialiased;
}

a { color: var(--ink); text-decoration: none; }
a:hover { color: var(--primary); }
ul { list-style: none; }
img { max-width: 100%; height: auto; display: block; }

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
}

.site-header {
    background: var(--canvas);
    border-bottom: 1px solid var(--hairline);
    position: sticky;
    top: 0;
    z-index: 100;
}

.header-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 64px;
    gap: 24px;
}

.site-logo {
    font-size: 18px;
    font-weight: 600;
    color: var(--ink);
    letter-spacing: -0.02em;
    flex-shrink: 0;
}

.site-logo:hover { color: var(--primary); }

.site-nav ul {
    display: flex;
    gap: 32px;
    align-items: center;
}

.site-nav a {
    font-size: 14px;
    font-weight: 500;
    color: var(--body);
    line-height: 1.4;
    transition: color 0.15s;
}

.site-nav a:hover,
.site-nav a.active { color: var(--ink); }

.nav-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 4px;
}

.nav-toggle span {
    display: block;
    width: 22px;
    height: 2px;
    background: var(--ink);
    border-radius: 2px;
    transition: transform 0.2s, opacity 0.2s;
}

.badge-pill {
    display: inline-flex;
    align-items: center;
    background: var(--surface-strong);
    color: var(--ink);
    font-size: 11px;
    font-weight: 600;
    letter-spacing: 0.88px;
    text-transform: uppercase;
    border-radius: var(--radius-pill);
    padding: 4px 10px;
}

.hero-band {
    padding: calc(var(--section) * 1.2) 0 var(--section);
    background: var(--canvas);
}

.hero-content {
    max-width: 780px;
}

.hero-label {
    margin-bottom: 20px;
}

.hero-band h1 {
    font-size: 52px;
    font-weight: 400;
    line-height: 1.1;
    letter-spacing: -1.2px;
    color: var(--ink);
    margin-bottom: 20px;
}

.hero-band p {
    font-size: 16px;
    color: var(--body);
    line-height: 1.6;
    max-width: 600px;
    margin-bottom: 32px;
}

.hero-meta {
    display: flex;
    gap: 20px;
    align-items: center;
    font-size: 13px;
    color: var(--muted);
}

.hero-meta span { display: flex; align-items: center; gap: 6px; }

.hero-img-wrap {
    margin-top: 48px;
    border-radius: var(--radius-lg);
    overflow: hidden;
    border: 1px solid var(--hairline);
    background: var(--surface-card);
    max-height: 440px;
}

.hero-img-wrap img {
    width: 100%;
    height: 440px;
    object-fit: cover;
}

section.content-band {
    padding: var(--section) 0;
}

section.content-band + section.content-band {
    border-top: 1px solid var(--hairline-soft);
}

.section-label {
    font-size: 11px;
    font-weight: 600;
    letter-spacing: 0.88px;
    text-transform: uppercase;
    color: var(--muted);
    margin-bottom: 12px;
}

h2.section-heading {
    font-size: 36px;
    font-weight: 400;
    letter-spacing: -0.72px;
    line-height: 1.2;
    color: var(--ink);
    margin-bottom: 16px;
}

h3.sub-heading {
    font-size: 26px;
    font-weight: 400;
    letter-spacing: -0.325px;
    line-height: 1.25;
    color: var(--ink);
    margin-bottom: 12px;
}

.section-body {
    font-size: 16px;
    color: var(--body);
    line-height: 1.6;
    max-width: 680px;
    margin-bottom: 40px;
}

.articles-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 24px;
}

.article-card {
    background: var(--surface-card);
    border: 1px solid var(--hairline);
    border-radius: var(--radius-lg);
    overflow: hidden;
    display: flex;
    flex-direction: column;
    transition: border-color 0.15s;
}

.article-card:hover { border-color: var(--hairline-strong); }

.article-card-img {
    height: 200px;
    overflow: hidden;
    background: var(--surface-strong);
}

.article-card-img img {
    width: 100%;
    height: 200px;
    object-fit: cover;
    transition: transform 0.3s;
}

.article-card:hover .article-card-img img { transform: scale(1.03); }

.article-card-body {
    padding: 24px;
    flex: 1;
    display: flex;
    flex-direction: column;
}

.article-card-tag {
    font-size: 11px;
    font-weight: 600;
    letter-spacing: 0.88px;
    text-transform: uppercase;
    color: var(--muted);
    margin-bottom: 8px;
}

.article-card-body h3 {
    font-size: 18px;
    font-weight: 600;
    color: var(--ink);
    line-height: 1.4;
    margin-bottom: 10px;
}

.article-card-body p {
    font-size: 14px;
    color: var(--body);
    line-height: 1.5;
    flex: 1;
    margin-bottom: 16px;
}

.article-card-meta {
    font-size: 13px;
    color: var(--muted);
    border-top: 1px solid var(--hairline-soft);
    padding-top: 12px;
}

.read-link {
    display: inline-flex;
    align-items: center;
    gap: 4px;
    font-size: 14px;
    font-weight: 500;
    color: var(--primary);
    margin-top: 12px;
}

.read-link:hover { color: var(--primary-active); }

.info-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 24px;
    margin-top: 40px;
}

.info-card {
    background: var(--surface-card);
    border: 1px solid var(--hairline);
    border-radius: var(--radius-lg);
    padding: 24px;
}

.info-card-icon {
    width: 40px;
    height: 40px;
    background: var(--canvas);
    border: 1px solid var(--hairline);
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 16px;
    font-size: 18px;
}

.info-card h4 {
    font-size: 16px;
    font-weight: 600;
    color: var(--ink);
    margin-bottom: 8px;
}

.info-card p {
    font-size: 14px;
    color: var(--body);
    line-height: 1.5;
}

.topics-band {
    background: var(--canvas-soft);
    border-top: 1px solid var(--hairline);
    border-bottom: 1px solid var(--hairline);
}

.topic-list {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 16px;
    margin-top: 32px;
}

.topic-item {
    display: flex;
    gap: 12px;
    align-items: flex-start;
}

.topic-dot {
    width: 8px;
    height: 8px;
    border-radius: 50%;
    background: var(--primary);
    flex-shrink: 0;
    margin-top: 6px;
}

.topic-item h5 {
    font-size: 15px;
    font-weight: 600;
    color: var(--ink);
    margin-bottom: 4px;
}

.topic-item p {
    font-size: 13px;
    color: var(--body);
    line-height: 1.5;
}

.diagram-wrap {
    background: var(--surface-card);
    border: 1px solid var(--hairline);
    border-radius: var(--radius-lg);
    padding: 32px;
    text-align: center;
    margin-top: 40px;
}

.diagram-wrap img {
    max-height: 320px;
    margin: 0 auto;
}

.diagram-caption {
    font-size: 13px;
    color: var(--muted);
    margin-top: 12px;
    font-family: var(--font-mono);
}

.contact-band {
    background: var(--canvas);
}

.contact-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 48px;
    align-items: start;
    margin-top: 40px;
}

.contact-info h4 {
    font-size: 18px;
    font-weight: 600;
    color: var(--ink);
    margin-bottom: 12px;
}

.contact-info p {
    font-size: 15px;
    color: var(--body);
    line-height: 1.6;
    margin-bottom: 16px;
}

.contact-detail {
    display: flex;
    flex-direction: column;
    gap: 8px;
    margin-top: 20px;
}

.contact-detail span {
    font-size: 14px;
    color: var(--body);
    display: flex;
    align-items: center;
    gap: 8px;
}

.contact-form {
    background: var(--surface-card);
    border: 1px solid var(--hairline);
    border-radius: var(--radius-lg);
    padding: 32px;
}

.form-group {
    margin-bottom: 20px;
}

.form-group label {
    display: block;
    font-size: 13px;
    font-weight: 600;
    color: var(--ink);
    margin-bottom: 6px;
    letter-spacing: 0.2px;
}

.form-group input,
.form-group textarea {
    width: 100%;
    background: var(--surface-card);
    color: var(--ink);
    border: 1px solid var(--hairline-strong);
    border-radius: var(--radius-md);
    padding: 12px 16px;
    font-family: var(--font-sans);
    font-size: 15px;
    line-height: 1.5;
    transition: border-color 0.15s;
    outline: none;
}

.form-group input:focus,
.form-group textarea:focus {
    border-color: var(--ink);
}

.form-group textarea {
    height: 100px;
    resize: vertical;
}

.btn-primary {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    background: var(--primary);
    color: var(--on-primary);
    border: none;
    border-radius: var(--radius-md);
    padding: 10px 18px;
    height: 40px;
    font-size: 14px;
    font-weight: 500;
    font-family: var(--font-sans);
    cursor: pointer;
    transition: background 0.15s;
    width: 100%;
}

.btn-primary:hover { background: var(--primary-active); }
.btn-primary:disabled { opacity: 0.6; cursor: not-allowed; }

.form-message {
    margin-top: 12px;
    font-size: 14px;
    font-weight: 500;
    padding: 10px 14px;
    border-radius: var(--radius-md);
    display: none;
}

.form-message.success {
    background: #e8f7f3;
    color: var(--success);
    border: 1px solid #b3e0d5;
}

.form-message.error {
    background: #fce8ec;
    color: var(--error);
    border: 1px solid #f5b8c4;
}

.article-layout {
    display: grid;
    grid-template-columns: 1fr 300px;
    gap: 48px;
    align-items: start;
    padding: var(--section) 0;
}

.article-main h1 {
    font-size: 42px;
    font-weight: 400;
    letter-spacing: -0.84px;
    line-height: 1.15;
    color: var(--ink);
    margin-bottom: 20px;
}

.article-main .article-meta {
    display: flex;
    gap: 16px;
    align-items: center;
    font-size: 13px;
    color: var(--muted);
    padding-bottom: 20px;
    border-bottom: 1px solid var(--hairline);
    margin-bottom: 28px;
    flex-wrap: wrap;
}

.article-main .article-meta .tag {
    background: var(--surface-strong);
    color: var(--ink);
    font-size: 11px;
    font-weight: 600;
    letter-spacing: 0.88px;
    text-transform: uppercase;
    border-radius: var(--radius-pill);
    padding: 3px 10px;
}

.article-content h2 {
    font-size: 26px;
    font-weight: 400;
    letter-spacing: -0.325px;
    color: var(--ink);
    margin: 36px 0 14px;
    line-height: 1.25;
}

.article-content h3 {
    font-size: 20px;
    font-weight: 600;
    color: var(--ink);
    margin: 28px 0 10px;
}

.article-content p {
    font-size: 16px;
    color: var(--body);
    line-height: 1.7;
    margin-bottom: 18px;
}

.article-content ul,
.article-content ol {
    margin: 0 0 18px 0;
    padding-left: 20px;
}

.article-content ul { list-style: disc; }
.article-content ol { list-style: decimal; }

.article-content li {
    font-size: 16px;
    color: var(--body);
    line-height: 1.6;
    margin-bottom: 6px;
}

.article-content a {
    color: var(--primary);
    text-decoration: underline;
    text-decoration-color: rgba(245, 78, 0, 0.3);
}

.article-content a:hover {
    color: var(--primary-active);
}

.article-img {
    margin: 28px 0;
    border-radius: var(--radius-lg);
    overflow: hidden;
    border: 1px solid var(--hairline);
}

.article-img img {
    width: 100%;
    height: 320px;
    object-fit: cover;
}

.article-img figcaption {
    font-size: 13px;
    color: var(--muted);
    padding: 10px 16px;
    background: var(--canvas-soft);
    font-family: var(--font-mono);
}

.callout-box {
    background: var(--surface-card);
    border: 1px solid var(--hairline);
    border-left: 3px solid var(--primary);
    border-radius: var(--radius-md);
    padding: 20px 24px;
    margin: 24px 0;
}

.callout-box p {
    margin: 0;
    color: var(--body-strong);
}

.comparison-table {
    width: 100%;
    border-collapse: collapse;
    margin: 24px 0;
    font-size: 15px;
}

.comparison-table th {
    background: var(--canvas-soft);
    color: var(--ink);
    font-weight: 600;
    font-size: 13px;
    text-align: left;
    padding: 12px 16px;
    border: 1px solid var(--hairline);
}

.comparison-table td {
    padding: 11px 16px;
    border: 1px solid var(--hairline);
    color: var(--body);
    vertical-align: top;
}

.comparison-table tr:nth-child(even) td {
    background: var(--canvas-soft);
}

.code-block {
    background: var(--surface-card);
    border: 1px solid var(--hairline);
    border-radius: var(--radius-lg);
    padding: 20px;
    font-family: var(--font-mono);
    font-size: 13px;
    color: var(--ink);
    line-height: 1.5;
    overflow-x: auto;
    margin: 24px 0;
}

.article-sidebar {
    position: sticky;
    top: 80px;
}

.sidebar-card {
    background: var(--surface-card);
    border: 1px solid var(--hairline);
    border-radius: var(--radius-lg);
    padding: 24px;
    margin-bottom: 20px;
}

.sidebar-card h4 {
    font-size: 13px;
    font-weight: 600;
    letter-spacing: 0.88px;
    text-transform: uppercase;
    color: var(--muted);
    margin-bottom: 14px;
}

.sidebar-card ul li {
    padding: 8px 0;
    border-bottom: 1px solid var(--hairline-soft);
}

.sidebar-card ul li:last-child { border-bottom: none; }

.sidebar-card ul li a {
    font-size: 14px;
    color: var(--body);
    line-height: 1.4;
}

.sidebar-card ul li a:hover { color: var(--primary); }

.toc-list { counter-reset: toc; }

.toc-list li {
    counter-increment: toc;
    padding: 7px 0;
    border-bottom: 1px solid var(--hairline-soft);
}

.toc-list li:last-child { border-bottom: none; }

.toc-list li a {
    font-size: 13px;
    color: var(--body);
    display: flex;
    gap: 8px;
}

.toc-list li a::before {
    content: counter(toc, decimal-leading-zero);
    font-family: var(--font-mono);
    color: var(--muted-soft);
    font-size: 11px;
    flex-shrink: 0;
    margin-top: 1px;
}

.toc-list li a:hover { color: var(--primary); }

.page-band {
    padding: var(--section) 0;
}

.page-band h1 {
    font-size: 42px;
    font-weight: 400;
    letter-spacing: -0.84px;
    color: var(--ink);
    margin-bottom: 12px;
}

.page-band .page-subtitle {
    font-size: 16px;
    color: var(--muted);
    margin-bottom: 40px;
    border-bottom: 1px solid var(--hairline);
    padding-bottom: 24px;
}

.page-content h2 {
    font-size: 22px;
    font-weight: 600;
    color: var(--ink);
    margin: 36px 0 12px;
}

.page-content p {
    font-size: 16px;
    color: var(--body);
    line-height: 1.7;
    margin-bottom: 16px;
    max-width: 720px;
}

.page-content ul {
    list-style: disc;
    padding-left: 20px;
    margin-bottom: 16px;
}

.page-content li {
    font-size: 16px;
    color: var(--body);
    line-height: 1.6;
    margin-bottom: 6px;
}

.page-content a {
    color: var(--primary);
    text-decoration: underline;
}

.site-footer {
    background: var(--canvas);
    border-top: 1px solid var(--hairline);
    padding: 64px 0 0;
}

.footer-inner {
    display: grid;
    grid-template-columns: 2fr 1.5fr 1fr 1fr 1.5fr;
    gap: 40px;
    padding-bottom: 48px;
}

.footer-brand {
    font-size: 16px;
    font-weight: 600;
    color: var(--ink);
    display: block;
    margin-bottom: 10px;
}

.footer-desc {
    font-size: 14px;
    color: var(--body);
    line-height: 1.6;
}

.footer-heading {
    display: block;
    font-size: 11px;
    font-weight: 600;
    letter-spacing: 0.88px;
    text-transform: uppercase;
    color: var(--muted);
    margin-bottom: 12px;
}

.footer-col ul li {
    margin-bottom: 8px;
}

.footer-col ul li a {
    font-size: 14px;
    color: var(--body);
}

.footer-col ul li a:hover { color: var(--ink); }

.footer-disclaimer {
    font-size: 12px;
    color: var(--muted-soft);
    margin-top: 16px;
    line-height: 1.5;
}

.footer-bottom {
    border-top: 1px solid var(--hairline);
    padding: 20px 0;
}

.footer-bottom .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 13px;
    color: var(--muted);
}

.cookie-banner {
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    background: var(--ink);
    color: var(--canvas);
    z-index: 1000;
    padding: 16px 0;
    display: none;
}

.cookie-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 20px;
    flex-wrap: wrap;
}

.cookie-text {
    font-size: 14px;
    line-height: 1.5;
    color: var(--canvas);
    flex: 1;
}

.cookie-text a {
    color: var(--canvas);
    text-decoration: underline;
}

.cookie-actions {
    display: flex;
    gap: 10px;
    flex-shrink: 0;
}

.btn-cookie-accept,
.btn-cookie-reject {
    padding: 8px 16px;
    border-radius: var(--radius-md);
    font-size: 13px;
    font-weight: 500;
    cursor: pointer;
    border: none;
    font-family: var(--font-sans);
}

.btn-cookie-accept {
    background: var(--primary);
    color: var(--on-primary);
}

.btn-cookie-accept:hover { background: var(--primary-active); }

.btn-cookie-reject {
    background: transparent;
    color: var(--canvas);
    border: 1px solid rgba(247,247,244,0.3);
}

.btn-cookie-reject:hover {
    background: rgba(247,247,244,0.1);
}

.breadcrumb {
    display: flex;
    gap: 8px;
    align-items: center;
    font-size: 13px;
    color: var(--muted);
    padding: 16px 0;
    flex-wrap: wrap;
}

.breadcrumb a { color: var(--muted); }
.breadcrumb a:hover { color: var(--primary); }
.breadcrumb .sep { color: var(--muted-soft); }

.articles-header {
    padding: 48px 0 40px;
    border-bottom: 1px solid var(--hairline);
    margin-bottom: 48px;
}

.articles-header h1 {
    font-size: 42px;
    font-weight: 400;
    letter-spacing: -0.84px;
    color: var(--ink);
    margin-bottom: 12px;
}

.articles-header p {
    font-size: 16px;
    color: var(--body);
    max-width: 580px;
}

@media (max-width: 1024px) {
    .articles-grid { grid-template-columns: repeat(2, 1fr); }
    .info-grid { grid-template-columns: repeat(2, 1fr); }
    .footer-inner { grid-template-columns: repeat(3, 1fr); }
    .article-layout { grid-template-columns: 1fr; }
    .article-sidebar { position: static; }
    .contact-grid { grid-template-columns: 1fr; }
}

@media (max-width: 768px) {
    .nav-toggle { display: flex; }
    .site-nav {
        display: none;
        position: absolute;
        top: 64px;
        left: 0;
        right: 0;
        background: var(--canvas);
        border-bottom: 1px solid var(--hairline);
        padding: 16px 24px 24px;
        z-index: 99;
    }
    .site-nav.open { display: block; }
    .site-nav ul {
        flex-direction: column;
        gap: 4px;
        align-items: flex-start;
    }
    .site-nav a { padding: 8px 0; display: block; font-size: 15px; }
    .hero-band h1 { font-size: 36px; letter-spacing: -0.8px; }
    h2.section-heading { font-size: 28px; }
    .articles-grid { grid-template-columns: 1fr; }
    .info-grid { grid-template-columns: 1fr; }
    .footer-inner { grid-template-columns: 1fr 1fr; }
    .topic-list { grid-template-columns: 1fr; }
    .article-main h1 { font-size: 30px; }
    .page-band h1 { font-size: 30px; }
    .footer-bottom .container { flex-direction: column; gap: 8px; text-align: center; }
    .cookie-inner { flex-direction: column; align-items: flex-start; }
}

@media (max-width: 480px) {
    .hero-band h1 { font-size: 28px; }
    .footer-inner { grid-template-columns: 1fr; }
    .articles-header h1 { font-size: 28px; }
    .comparison-table { font-size: 13px; }
    .comparison-table th, .comparison-table td { padding: 8px 10px; }
}