@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600&family=JetBrains+Mono:wght@400&display=swap');

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

:root {
    --canvas: #f7f7f4;
    --canvas-soft: #fafaf7;
    --surface-card: #ffffff;
    --surface-strong: #e6e5e0;
    --primary: #f54e00;
    --primary-active: #d04200;
    --on-primary: #ffffff;
    --ink: #26251e;
    --body: #5a5852;
    --body-strong: #26251e;
    --muted: #807d72;
    --muted-soft: #a09c92;
    --hairline: #e6e5e0;
    --hairline-soft: #efeee8;
    --hairline-strong: #cfcdc4;
    --semantic-success: #1f8a65;
    --semantic-error: #cf2d56;
    --rounded-xs: 4px;
    --rounded-sm: 6px;
    --rounded-md: 8px;
    --rounded-lg: 12px;
    --rounded-xl: 16px;
    --rounded-pill: 9999px;
}

html {
    font-size: 16px;
    scroll-behavior: smooth;
}

body {
    background-color: var(--canvas);
    color: var(--body);
    font-family: 'Inter', system-ui, 'Helvetica Neue', Helvetica, Arial, sans-serif;
    font-size: 16px;
    font-weight: 400;
    line-height: 1.5;
    -webkit-font-smoothing: antialiased;
}

a {
    color: var(--ink);
    text-decoration: none;
    transition: color 0.15s ease;
}

a:hover {
    color: var(--primary);
}

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

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

.section {
    padding: 80px 0;
}

.section-sm {
    padding: 48px 0;
}

h1, h2, h3, h4, h5 {
    color: var(--ink);
    font-weight: 400;
    line-height: 1.2;
}

h1 { font-size: 72px; letter-spacing: -2.16px; line-height: 1.1; }
h2 { font-size: 36px; letter-spacing: -0.72px; }
h3 { font-size: 26px; letter-spacing: -0.325px; line-height: 1.25; }
h4 { font-size: 22px; letter-spacing: -0.11px; line-height: 1.3; }

.title-md { font-size: 18px; font-weight: 600; line-height: 1.4; color: var(--ink); }
.title-sm { font-size: 16px; font-weight: 600; line-height: 1.4; color: var(--ink); }

.body-sm { font-size: 14px; line-height: 1.5; }
.caption { font-size: 13px; line-height: 1.4; color: var(--muted); }

.label-upper {
    font-size: 11px;
    font-weight: 600;
    line-height: 1.4;
    letter-spacing: 0.88px;
    text-transform: uppercase;
    color: var(--muted);
}

code, pre, .code {
    font-family: 'JetBrains Mono', 'Courier New', monospace;
    font-size: 13px;
}

.btn-primary {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    background: var(--primary);
    color: var(--on-primary);
    font-size: 14px;
    font-weight: 500;
    line-height: 1;
    padding: 10px 18px;
    height: 40px;
    border-radius: var(--rounded-md);
    border: none;
    cursor: pointer;
    transition: background 0.15s ease;
    text-decoration: none;
}

.btn-primary:hover {
    background: var(--primary-active);
    color: var(--on-primary);
}

.btn-secondary {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    background: var(--surface-card);
    color: var(--ink);
    font-size: 14px;
    font-weight: 500;
    line-height: 1;
    padding: 10px 18px;
    height: 40px;
    border-radius: var(--rounded-md);
    border: 1px solid var(--hairline-strong);
    cursor: pointer;
    transition: border-color 0.15s ease;
    text-decoration: none;
}

.btn-secondary:hover {
    border-color: var(--ink);
    color: var(--ink);
}

.badge {
    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;
    padding: 4px 10px;
    border-radius: var(--rounded-pill);
}

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

.divider {
    border: none;
    border-top: 1px solid var(--hairline);
    margin: 0;
}

nav.site-nav {
    background: var(--canvas);
    border-bottom: 1px solid var(--hairline);
    position: sticky;
    top: 0;
    z-index: 100;
    height: 64px;
    display: flex;
    align-items: center;
}

.nav-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    width: 100%;
}

.nav-logo {
    font-size: 18px;
    font-weight: 600;
    color: var(--ink);
    letter-spacing: -0.5px;
    text-decoration: none;
}

.nav-logo span {
    color: var(--primary);
}

.nav-links {
    display: flex;
    align-items: center;
    gap: 32px;
    list-style: none;
}

.nav-links a {
    font-size: 14px;
    font-weight: 500;
    color: var(--body);
    text-decoration: none;
    transition: color 0.15s ease;
}

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

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

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

.nav-mobile {
    display: none;
    position: absolute;
    top: 64px;
    left: 0;
    right: 0;
    background: var(--canvas);
    border-bottom: 1px solid var(--hairline);
    padding: 16px 24px;
}

.nav-mobile.open {
    display: block;
}

.nav-mobile ul {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 4px;
}

.nav-mobile ul a {
    display: block;
    padding: 10px 0;
    font-size: 16px;
    font-weight: 500;
    color: var(--body);
    border-bottom: 1px solid var(--hairline-soft);
}

.hero {
    padding: 96px 0 80px;
    background: var(--canvas);
}

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

.hero h1 {
    margin-bottom: 24px;
    max-width: 720px;
}

.hero p {
    font-size: 18px;
    color: var(--body);
    max-width: 560px;
    margin-bottom: 36px;
    line-height: 1.6;
}

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

.hero-image {
    margin-top: 64px;
    border-radius: var(--rounded-lg);
    overflow: hidden;
    border: 1px solid var(--hairline);
    background: var(--surface-card);
}

.hero-image img {
    width: 100%;
    height: 420px;
    object-fit: cover;
}

.section-label {
    margin-bottom: 16px;
}

.section-head {
    margin-bottom: 48px;
}

.section-head h2 {
    margin-bottom: 12px;
}

.section-head p {
    color: var(--body);
    max-width: 560px;
    font-size: 18px;
    line-height: 1.6;
}

.grid-3 {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 20px;
}

.grid-2 {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 24px;
}

.card-icon {
    width: 40px;
    height: 40px;
    background: var(--surface-strong);
    border-radius: var(--rounded-sm);
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 16px;
    font-size: 18px;
}

.card h3 {
    font-size: 18px;
    font-weight: 600;
    margin-bottom: 8px;
    color: var(--ink);
}

.card p {
    color: var(--body);
    font-size: 15px;
    line-height: 1.6;
}

.card-link {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    font-size: 14px;
    font-weight: 500;
    color: var(--primary);
    margin-top: 16px;
    text-decoration: none;
}

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

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

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

.article-card-image {
    height: 200px;
    overflow: hidden;
    background: var(--canvas-soft);
}

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

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

.article-card-body {
    padding: 24px;
}

.article-card-body .badge {
    margin-bottom: 12px;
}

.article-card-body h3 {
    font-size: 20px;
    font-weight: 400;
    letter-spacing: -0.2px;
    margin-bottom: 10px;
    color: var(--ink);
    line-height: 1.3;
}

.article-card-body p {
    font-size: 14px;
    color: var(--body);
    line-height: 1.6;
    margin-bottom: 16px;
}

.article-meta {
    display: flex;
    align-items: center;
    gap: 12px;
    font-size: 12px;
    color: var(--muted);
}

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

.article-page-hero {
    padding: 64px 0 48px;
}

.article-page-hero .badge {
    margin-bottom: 20px;
}

.article-page-hero h1 {
    font-size: 52px;
    letter-spacing: -1.5px;
    max-width: 800px;
    margin-bottom: 20px;
}

.article-page-hero .lead {
    font-size: 20px;
    color: var(--body);
    max-width: 680px;
    line-height: 1.6;
}

.article-page-meta {
    display: flex;
    align-items: center;
    gap: 20px;
    font-size: 13px;
    color: var(--muted);
    margin-top: 24px;
    padding-top: 24px;
    border-top: 1px solid var(--hairline);
}

.article-content {
    max-width: 760px;
}

.article-content h2 {
    font-size: 28px;
    letter-spacing: -0.5px;
    margin-top: 48px;
    margin-bottom: 16px;
    color: var(--ink);
}

.article-content h3 {
    font-size: 22px;
    letter-spacing: -0.3px;
    margin-top: 36px;
    margin-bottom: 12px;
    color: var(--ink);
}

.article-content p {
    color: var(--body);
    font-size: 16px;
    line-height: 1.7;
    margin-bottom: 20px;
}

.article-content ul,
.article-content ol {
    padding-left: 24px;
    margin-bottom: 20px;
    color: var(--body);
}

.article-content li {
    line-height: 1.7;
    margin-bottom: 6px;
}

.article-content a {
    color: var(--primary);
    text-decoration: underline;
    text-decoration-color: transparent;
    transition: text-decoration-color 0.15s;
}

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

.code-block {
    background: var(--surface-card);
    border: 1px solid var(--hairline);
    border-radius: var(--rounded-lg);
    padding: 20px;
    margin: 24px 0;
    overflow-x: auto;
}

.code-block pre {
    font-family: 'JetBrains Mono', monospace;
    font-size: 13px;
    line-height: 1.6;
    color: var(--ink);
    white-space: pre-wrap;
    word-break: break-word;
}

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

.info-box p {
    margin-bottom: 0;
    font-size: 15px;
}

.article-image {
    margin: 32px 0;
    border-radius: var(--rounded-lg);
    overflow: hidden;
    border: 1px solid var(--hairline);
}

.article-image img {
    width: 100%;
    height: 360px;
    object-fit: cover;
}

.article-image figcaption {
    padding: 10px 16px;
    font-size: 13px;
    color: var(--muted);
    background: var(--surface-card);
}

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

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

.sidebar-card h4 {
    font-size: 14px;
    font-weight: 600;
    color: var(--ink);
    margin-bottom: 16px;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.sidebar-card ul {
    list-style: none;
    padding: 0;
}

.sidebar-card ul li {
    padding: 8px 0;
    border-bottom: 1px solid var(--hairline-soft);
    font-size: 14px;
}

.sidebar-card ul li:last-child {
    border-bottom: none;
    padding-bottom: 0;
}

.sidebar-card ul li a {
    color: var(--body);
    text-decoration: none;
}

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

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

.form-group label {
    display: block;
    font-size: 14px;
    font-weight: 500;
    color: var(--ink);
    margin-bottom: 8px;
}

.form-group input,
.form-group textarea,
.form-group select {
    width: 100%;
    background: var(--surface-card);
    color: var(--ink);
    border: 1px solid var(--hairline-strong);
    border-radius: var(--rounded-md);
    padding: 12px 16px;
    height: 44px;
    font-family: inherit;
    font-size: 15px;
    transition: border-color 0.15s ease;
    outline: none;
}

.form-group textarea {
    height: auto;
    min-height: 120px;
    resize: vertical;
}

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

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

.form-error {
    font-size: 12px;
    color: var(--semantic-error);
    margin-top: 6px;
    display: none;
}

.form-error.show {
    display: block;
}

.form-success {
    background: #f0fdf4;
    border: 1px solid var(--semantic-success);
    border-radius: var(--rounded-md);
    padding: 16px 20px;
    font-size: 14px;
    color: var(--semantic-success);
    display: none;
    margin-top: 16px;
}

.form-success.show {
    display: block;
}

.form-loading {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    font-size: 14px;
    color: var(--muted);
    display: none;
}

.form-loading.show {
    display: inline-flex;
}

.spinner {
    width: 16px;
    height: 16px;
    border: 2px solid var(--hairline);
    border-top-color: var(--primary);
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

.cookie-banner {
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    background: var(--ink);
    color: var(--canvas);
    padding: 20px 24px;
    z-index: 999;
    display: none;
}

.cookie-banner.show {
    display: block;
}

.cookie-inner {
    max-width: 1200px;
    margin: 0 auto;
    display: flex;
    align-items: center;
    gap: 24px;
    flex-wrap: wrap;
}

.cookie-text {
    flex: 1;
    font-size: 14px;
    color: #cfcdc4;
    line-height: 1.5;
}

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

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

.btn-cookie-accept {
    background: var(--primary);
    color: var(--on-primary);
    border: none;
    padding: 8px 18px;
    border-radius: var(--rounded-md);
    font-size: 14px;
    font-weight: 500;
    cursor: pointer;
}

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

.btn-cookie-reject {
    background: transparent;
    color: var(--canvas);
    border: 1px solid #cfcdc4;
    padding: 8px 18px;
    border-radius: var(--rounded-md);
    font-size: 14px;
    font-weight: 500;
    cursor: pointer;
}

.btn-cookie-reject:hover {
    border-color: var(--canvas);
}

.page-hero {
    padding: 64px 0 48px;
    border-bottom: 1px solid var(--hairline);
}

.page-hero h1 {
    font-size: 48px;
    letter-spacing: -1.2px;
    margin-bottom: 16px;
    max-width: 640px;
}

.page-hero p {
    font-size: 18px;
    color: var(--body);
    max-width: 560px;
    line-height: 1.6;
}

.page-content {
    padding: 64px 0;
    max-width: 760px;
}

.page-content h2 {
    font-size: 26px;
    letter-spacing: -0.4px;
    margin-top: 40px;
    margin-bottom: 14px;
    color: var(--ink);
}

.page-content h3 {
    font-size: 20px;
    margin-top: 28px;
    margin-bottom: 10px;
    color: var(--ink);
}

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

.page-content ul {
    padding-left: 20px;
    margin-bottom: 16px;
    color: var(--body);
}

.page-content li {
    line-height: 1.7;
    margin-bottom: 6px;
}

.footer {
    background: var(--canvas);
    border-top: 1px solid var(--hairline);
    padding: 64px 0 48px;
}

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

.footer-brand p {
    font-size: 14px;
    color: var(--body);
    line-height: 1.6;
    margin-top: 12px;
    max-width: 280px;
}

.footer-col h5 {
    font-size: 12px;
    font-weight: 600;
    letter-spacing: 0.88px;
    text-transform: uppercase;
    color: var(--muted);
    margin-bottom: 16px;
}

.footer-col ul {
    list-style: none;
}

.footer-col ul li {
    margin-bottom: 10px;
}

.footer-col ul li a {
    font-size: 14px;
    color: var(--body);
    text-decoration: none;
    transition: color 0.15s;
}

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

.footer-bottom {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding-top: 24px;
    border-top: 1px solid var(--hairline);
    font-size: 13px;
    color: var(--muted);
}

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

.toc h4 {
    font-size: 12px;
    font-weight: 600;
    letter-spacing: 0.88px;
    text-transform: uppercase;
    color: var(--muted);
    margin-bottom: 14px;
}

.toc ol {
    list-style: none;
    padding: 0;
    counter-reset: toc;
}

.toc li {
    counter-increment: toc;
    padding: 7px 0;
    border-bottom: 1px solid var(--hairline-soft);
    display: flex;
    align-items: flex-start;
    gap: 10px;
    font-size: 14px;
}

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

.toc li::before {
    content: counter(toc);
    font-size: 11px;
    font-weight: 600;
    color: var(--muted);
    min-width: 16px;
    padding-top: 1px;
}

.toc li a {
    color: var(--body);
    text-decoration: none;
    line-height: 1.4;
}

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

.related-articles {
    padding: 64px 0;
    border-top: 1px solid var(--hairline);
}

.related-articles h2 {
    font-size: 26px;
    letter-spacing: -0.4px;
    margin-bottom: 32px;
}

@media (max-width: 1024px) {
    h1 { font-size: 56px; letter-spacing: -1.5px; }
    .grid-3 { grid-template-columns: repeat(2, 1fr); }
    .footer-grid { grid-template-columns: 1fr 1fr 1fr; }
    .footer-brand { grid-column: span 3; }
}

@media (max-width: 768px) {
    h1 { font-size: 36px; letter-spacing: -0.8px; }
    h2 { font-size: 28px; }
    h3 { font-size: 22px; }
    .hero { padding: 56px 0 48px; }
    .section { padding: 56px 0; }
    .grid-3, .grid-2 { grid-template-columns: 1fr; }
    .nav-links { display: none; }
    .nav-hamburger { display: flex; }
    .footer-grid { grid-template-columns: 1fr 1fr; }
    .footer-brand { grid-column: span 2; }
    .article-page-hero h1 { font-size: 34px; letter-spacing: -0.8px; }
    .article-layout { flex-direction: column; }
    .sidebar { position: static; }
    .footer-bottom { flex-direction: column; gap: 8px; text-align: center; }
}

@media (max-width: 640px) {
    .container { padding: 0 16px; }
    h1 { font-size: 30px; letter-spacing: -0.5px; }
    .hero-image img { height: 220px; }
    .footer-grid { grid-template-columns: 1fr; }
    .footer-brand { grid-column: span 1; }
    .cookie-inner { flex-direction: column; align-items: flex-start; }
}

.article-layout {
    display: flex;
    gap: 48px;
    align-items: flex-start;
}

.article-main {
    flex: 1;
    min-width: 0;
}

.article-aside {
    width: 280px;
    flex-shrink: 0;
}

.breadcrumbs {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 13px;
    color: var(--muted);
    margin-bottom: 24px;
}

.breadcrumbs a {
    color: var(--muted);
    text-decoration: none;
}

.breadcrumbs a:hover {
    color: var(--ink);
}

.breadcrumbs span {
    color: var(--hairline-strong);
}