/* systemshardening.com - professional, readable, fast */

:root {
  --color-bg: #f8f9fa;
  --color-surface: #ffffff;
  --color-text: #1a1a2e;
  --color-text-muted: #5a6072;
  --color-text-light: #8891a4;
  --color-accent: #2563eb;
  --color-accent-hover: #1d4ed8;
  --color-accent-subtle: #eff4ff;
  --color-border: #e2e5ea;
  --color-border-light: #eef0f3;
  --color-code-bg: #f1f3f5;
  --color-header-bg: #1b2137;
  --color-header-text: #e2e5ea;
  --color-header-accent: #60a5fa;
  --color-green: #16a34a;
  --color-red: #dc2626;

  /* Category colors */
  --cat-linux: #16a34a;
  --cat-linux-bg: #ecfdf5;
  --cat-kubernetes: #2563eb;
  --cat-kubernetes-bg: #eff6ff;
  --cat-network: #7c3aed;
  --cat-network-bg: #f5f3ff;
  --cat-cicd: #ea580c;
  --cat-cicd-bg: #fff7ed;
  --cat-observability: #0d9488;
  --cat-observability-bg: #f0fdfa;
  --cat-ai-landscape: #4f46e5;
  --cat-ai-landscape-bg: #eef2ff;
  --cat-cross-cutting: #475569;
  --cat-cross-cutting-bg: #f8fafc;

  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --font-mono: "SF Mono", "Fira Code", "Fira Mono", "Roboto Mono", Consolas, monospace;
  --max-width: 820px;
  --max-width-wide: 1080px;
  --radius: 8px;
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
  --shadow-md: 0 2px 8px rgba(0, 0, 0, 0.08);
  --shadow-lg: 0 4px 16px rgba(0, 0, 0, 0.1);
}

/* ========================================
   Dark mode overrides
   ======================================== */

[data-theme="dark"] {
  --color-bg: #0f1117;
  --color-surface: #1a1d2e;
  --color-text: #e2e5ea;
  --color-text-muted: #8891a4;
  --color-text-light: #5a6072;
  --color-accent: #60a5fa;
  --color-accent-hover: #93bbfd;
  --color-accent-subtle: rgba(96, 165, 250, 0.1);
  --color-border: #2a2d3e;
  --color-border-light: #1f2233;
  --color-code-bg: #1a1d2e;
  --color-header-bg: #0a0c14;
  --color-green: #4ade80;
  --color-red: #f87171;

  --cat-linux-bg: rgba(22, 163, 74, 0.12);
  --cat-kubernetes-bg: rgba(37, 99, 235, 0.12);
  --cat-network-bg: rgba(124, 58, 237, 0.12);
  --cat-cicd-bg: rgba(234, 88, 12, 0.12);
  --cat-observability-bg: rgba(13, 148, 136, 0.12);
  --cat-ai-landscape-bg: rgba(79, 70, 229, 0.12);
  --cat-cross-cutting-bg: rgba(71, 85, 105, 0.15);

  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.2);
  --shadow-md: 0 2px 8px rgba(0, 0, 0, 0.3);
  --shadow-lg: 0 4px 16px rgba(0, 0, 0, 0.4);
}

[data-theme="dark"] .article-content pre {
  background: #0d0f18;
  border-color: rgba(255, 255, 255, 0.04);
}

[data-theme="dark"] .article-content tr:nth-child(even) {
  background: rgba(255, 255, 255, 0.02);
}

[data-theme="dark"] .article-content tr:hover {
  background: rgba(96, 165, 250, 0.05);
}

[data-theme="dark"] .article-content blockquote {
  background: rgba(96, 165, 250, 0.08);
}

[data-theme="dark"] .article-content a {
  text-decoration-color: rgba(96, 165, 250, 0.3);
}

[data-theme="dark"] .tag {
  background: #1a1d2e;
  color: #8891a4;
}

/* Theme toggle button */
.theme-toggle {
  background: none;
  border: none;
  color: var(--color-header-text);
  font-size: 1.1rem;
  width: 2.5rem;
  height: 2.5rem;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border-radius: 6px;
  cursor: pointer;
  transition: background 0.15s, color 0.15s;
  line-height: 1;
}

.theme-toggle:hover {
  color: #ffffff;
  background: rgba(255, 255, 255, 0.1);
}

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

body {
  font-family: var(--font-sans);
  color: var(--color-text);
  background: var(--color-bg);
  line-height: 1.7;
  font-size: 17px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* ========================================
   Layout
   ======================================== */

.site-header-wrap {
  background: var(--color-header-bg);
}

.site-header {
  max-width: var(--max-width-wide);
  margin: 0 auto;
  padding: 0 1.5rem;
}

main {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 2.5rem 1.5rem 4rem;
}

main.main-wide {
  max-width: var(--max-width-wide);
}

.site-footer-wrap {
  background: var(--color-header-bg);
}

.site-footer {
  max-width: var(--max-width-wide);
  margin: 0 auto;
  padding: 0 1.5rem;
}

/* ========================================
   Header
   ======================================== */

.site-header {
  padding-top: 1rem;
  padding-bottom: 1rem;
}

.header-top {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 0.5rem;
}

.site-logo {
  font-size: 1.15rem;
  font-weight: 700;
  color: #ffffff;
  text-decoration: none;
  letter-spacing: -0.02em;
}

.logo-dot { color: var(--color-header-accent); }

.site-nav {
  display: flex;
  gap: 0.25rem;
}

.site-nav a {
  color: var(--color-header-text);
  text-decoration: none;
  font-size: 0.88rem;
  font-weight: 500;
  padding: 0.4rem 0.75rem;
  border-radius: 6px;
  transition: background 0.15s, color 0.15s;
}

.site-nav a:hover {
  color: #ffffff;
  background: rgba(255, 255, 255, 0.1);
}

.site-nav a[aria-current="page"] {
  color: #ffffff;
  background: rgba(255, 255, 255, 0.12);
}

/* ========================================
   Footer
   ======================================== */

.site-footer {
  padding-top: 2.5rem;
  padding-bottom: 2.5rem;
  color: var(--color-header-text);
  font-size: 0.88rem;
}

.footer-inner {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  align-items: flex-start;
  gap: 1.5rem;
}

.footer-tagline {
  color: var(--color-text-light);
  line-height: 1.5;
}

.footer-tagline p {
  margin-bottom: 0.35rem;
}

.footer-links {
  display: flex;
  gap: 1.5rem;
  align-items: center;
}

.footer-links a {
  color: var(--color-header-text);
  text-decoration: none;
  transition: color 0.15s;
}

.footer-links a:hover {
  color: var(--color-header-accent);
}

.footer-copy {
  width: 100%;
  margin-top: 1rem;
  padding-top: 1rem;
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  color: var(--color-text-light);
  font-size: 0.82rem;
}

.footer-built {
  color: var(--color-text-light);
  font-size: 0.82rem;
  font-style: italic;
}

/* ========================================
   Homepage hero
   ======================================== */

.page-home {
  max-width: var(--max-width);
}

.page-home h1 {
  font-size: 2.25rem;
  line-height: 1.15;
  letter-spacing: -0.03em;
  font-weight: 800;
  margin-bottom: 1rem;
  color: var(--color-text);
}

.page-home > p:first-of-type {
  font-size: 1.15rem;
  color: var(--color-text-muted);
  line-height: 1.6;
  margin-bottom: 1.75rem;
}

.page-home h2 {
  font-size: 1.5rem;
  margin-top: 2.5rem;
  margin-bottom: 0.75rem;
  letter-spacing: -0.02em;
  font-weight: 700;
}

.page-home p { margin-bottom: 1rem; }

.page-home ul {
  margin-bottom: 1rem;
  padding-left: 1.5rem;
}

.page-home li {
  margin-bottom: 0.4rem;
  line-height: 1.6;
}

.page-home ol {
  margin-bottom: 1rem;
  padding-left: 1.5rem;
}

.page-home ol li {
  margin-bottom: 0.4rem;
}

.page-home a {
  color: var(--color-accent);
  text-decoration: underline;
  text-underline-offset: 2px;
}

.page-home a:hover {
  color: var(--color-accent-hover);
}

/* Hero accent bar */
.hero-bar {
  display: block;
  width: 60px;
  height: 4px;
  background: linear-gradient(135deg, var(--color-accent), #7c3aed);
  border-radius: 2px;
  margin-bottom: 1.25rem;
}

/* ========================================
   Article
   ======================================== */

.article-header { margin-bottom: 2.5rem; }

.article-header h1 {
  font-size: 2.25rem;
  line-height: 1.15;
  margin: 0.5rem 0;
  letter-spacing: -0.03em;
  font-weight: 800;
}

.article-header time {
  color: var(--color-text-light);
  font-size: 0.85rem;
}

.article-meta {
  display: flex;
  gap: 0.75rem;
  flex-wrap: wrap;
  align-items: center;
  margin-bottom: 0.25rem;
}

/* Category badges with per-category colors */
.article-category {
  padding: 0.2rem 0.6rem;
  border-radius: 4px;
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 0.01em;
  text-transform: capitalize;
}

.article-category[data-cat="linux"] {
  background: var(--cat-linux-bg);
  color: var(--cat-linux);
}

.article-category[data-cat="kubernetes"] {
  background: var(--cat-kubernetes-bg);
  color: var(--cat-kubernetes);
}

.article-category[data-cat="network"] {
  background: var(--cat-network-bg);
  color: var(--cat-network);
}

.article-category[data-cat="cicd"] {
  background: var(--cat-cicd-bg);
  color: var(--cat-cicd);
}

.article-category[data-cat="observability"] {
  background: var(--cat-observability-bg);
  color: var(--cat-observability);
}

.article-category[data-cat="ai-landscape"] {
  background: var(--cat-ai-landscape-bg);
  color: var(--cat-ai-landscape);
}

.article-category[data-cat="cross-cutting"] {
  background: var(--cat-cross-cutting-bg);
  color: var(--cat-cross-cutting);
}

.article-difficulty {
  color: var(--color-text-light);
  font-size: 0.82rem;
  font-weight: 500;
}

.article-reading-time {
  color: var(--color-text-light);
  font-size: 0.82rem;
}

.article-tags {
  display: flex;
  gap: 0.4rem;
  flex-wrap: wrap;
  margin-top: 0.5rem;
}

.tag {
  background: var(--color-code-bg);
  color: var(--color-text-muted);
  padding: 0.15rem 0.5rem;
  border-radius: 4px;
  font-size: 0.75rem;
  font-family: var(--font-mono);
}

/* ========================================
   Article content
   ======================================== */

.article-content {
  font-size: 1.125rem;
  line-height: 1.75;
}

.article-content h2 {
  font-size: 1.75rem;
  margin-top: 3rem;
  margin-bottom: 0.75rem;
  padding-bottom: 0.35rem;
  border-bottom: 2px solid var(--color-border-light);
  letter-spacing: -0.02em;
  font-weight: 700;
  scroll-margin-top: 2rem;
}

.article-content h3 {
  font-size: 1.35rem;
  margin-top: 2.25rem;
  margin-bottom: 0.5rem;
  letter-spacing: -0.015em;
  font-weight: 600;
  scroll-margin-top: 2rem;
}

.article-content h4 {
  font-size: 1.1rem;
  margin-top: 1.75rem;
  margin-bottom: 0.4rem;
  font-weight: 600;
}

.article-content p { margin-bottom: 1.1rem; }

.article-content ul, .article-content ol {
  margin-bottom: 1.1rem;
  padding-left: 1.5rem;
}

.article-content li {
  margin-bottom: 0.35rem;
  line-height: 1.65;
}

.article-content li > ul,
.article-content li > ol {
  margin-top: 0.35rem;
  margin-bottom: 0.35rem;
}

.article-content a {
  color: var(--color-accent);
  text-decoration: underline;
  text-underline-offset: 2px;
  text-decoration-color: rgba(37, 99, 235, 0.3);
  transition: text-decoration-color 0.15s;
}

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

.article-content strong {
  font-weight: 650;
}

.article-content hr {
  border: none;
  border-top: 2px solid var(--color-border-light);
  margin: 2.5rem 0;
}

/* ========================================
   Blockquotes / Callouts
   ======================================== */

.article-content blockquote {
  margin: 1.5rem 0;
  padding: 1rem 1.25rem;
  border-left: 4px solid var(--color-accent);
  background: var(--color-accent-subtle);
  border-radius: 0 var(--radius) var(--radius) 0;
  color: var(--color-text);
  font-size: 0.98rem;
}

.article-content blockquote p {
  margin-bottom: 0.5rem;
}

.article-content blockquote p:last-child {
  margin-bottom: 0;
}

/* ========================================
   Code
   ======================================== */

.article-content code {
  font-family: var(--font-mono);
  font-size: 0.86em;
  background: var(--color-code-bg);
  padding: 0.15em 0.4em;
  border-radius: 4px;
  word-break: break-word;
}

.article-content pre {
  position: relative;
  background: #1e1e2e;
  color: #cdd6f4;
  padding: 1.25rem 1.5rem;
  border-radius: var(--radius);
  overflow-x: auto;
  margin-bottom: 1.5rem;
  line-height: 1.55;
  font-size: 0.875rem;
  box-shadow: var(--shadow-sm);
  border: 1px solid rgba(255, 255, 255, 0.06);
}

.article-content pre code {
  background: none;
  padding: 0;
  color: inherit;
  font-size: inherit;
  word-break: normal;
}

/* ========================================
   Tables
   ======================================== */

.table-wrap {
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  margin-bottom: 1.5rem;
  border-radius: var(--radius);
  border: 1px solid var(--color-border);
}

.article-content table {
  width: 100%;
  border-collapse: collapse;
  margin-bottom: 0;
  font-size: 0.9rem;
}

.article-content th, .article-content td {
  padding: 0.65rem 1rem;
  border-bottom: 1px solid var(--color-border-light);
  text-align: left;
}

.article-content th {
  background: var(--color-code-bg);
  font-weight: 600;
  white-space: nowrap;
  position: sticky;
  top: 0;
  z-index: 1;
  border-bottom: 2px solid var(--color-border);
}

.article-content tr:nth-child(even) {
  background: rgba(0, 0, 0, 0.015);
}

.article-content tr:hover {
  background: rgba(37, 99, 235, 0.03);
}

.article-content td:first-child {
  font-weight: 500;
}

/* ========================================
   Article footer
   ======================================== */

.article-footer {
  margin-top: 3.5rem;
  padding-top: 1.75rem;
  border-top: 2px solid var(--color-border-light);
  color: var(--color-text-muted);
  font-size: 0.9rem;
}

.article-nav {
  display: flex;
  gap: 1.5rem;
  margin-top: 0.75rem;
}

.article-nav a {
  color: var(--color-accent);
  text-decoration: none;
  font-weight: 500;
  transition: color 0.15s;
}

.article-nav a:hover {
  color: var(--color-accent-hover);
}

/* ========================================
   Article listing page
   ======================================== */

.articles-page-header {
  margin-bottom: 2rem;
}

.articles-page-header h1 {
  font-size: 2.25rem;
  font-weight: 800;
  letter-spacing: -0.03em;
  margin-bottom: 0.5rem;
}

.articles-page-header p {
  color: var(--color-text-muted);
  font-size: 1.05rem;
  line-height: 1.5;
}

.category-section {
  margin-bottom: 3rem;
}

.category-section h2 {
  font-size: 1.4rem;
  margin-bottom: 1.25rem;
  padding-bottom: 0.4rem;
  border-bottom: 2px solid var(--color-border-light);
  letter-spacing: -0.02em;
  font-weight: 700;
}

.article-list {
  display: grid;
  grid-template-columns: 1fr;
  gap: 0.875rem;
}

.article-card {
  padding: 1.25rem 1.5rem;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  transition: border-color 0.15s, box-shadow 0.2s, transform 0.15s;
  box-shadow: var(--shadow-sm);
}

.article-card:hover {
  border-color: var(--color-accent);
  box-shadow: var(--shadow-md);
  transform: translateY(-1px);
}

.article-card h3 {
  font-size: 1.05rem;
  margin-bottom: 0.4rem;
  font-weight: 600;
  line-height: 1.35;
}

.article-card a {
  color: var(--color-text);
  text-decoration: none;
  transition: color 0.15s;
}

.article-card a:hover { color: var(--color-accent); }

.article-card-meta {
  display: flex;
  gap: 0.75rem;
  align-items: center;
  margin-bottom: 0.4rem;
}

.article-card-excerpt {
  color: var(--color-text-muted);
  font-size: 0.88rem;
  line-height: 1.5;
  margin-top: 0.4rem;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

/* ========================================
   Category nav
   ======================================== */

.category-nav {
  display: flex;
  gap: 0.5rem;
  flex-wrap: wrap;
  margin-bottom: 2.5rem;
}

.category-nav a {
  padding: 0.4rem 0.85rem;
  border: 1px solid var(--color-border);
  border-radius: 100px;
  color: var(--color-text-muted);
  text-decoration: none;
  font-size: 0.85rem;
  font-weight: 500;
  background: var(--color-surface);
  transition: border-color 0.15s, color 0.15s, background 0.15s;
  min-height: 44px;
  display: inline-flex;
  align-items: center;
}

.category-nav a:hover {
  border-color: var(--color-accent);
  color: var(--color-accent);
  background: var(--color-accent-subtle);
}

/* ========================================
   Page layout
   ======================================== */

.page h1 {
  font-size: 2.25rem;
  margin-bottom: 1.5rem;
  letter-spacing: -0.03em;
  font-weight: 800;
}

.page h2 {
  font-size: 1.5rem;
  margin-top: 2.25rem;
  margin-bottom: 0.75rem;
  letter-spacing: -0.02em;
  font-weight: 700;
}

.page p { margin-bottom: 1rem; }
.page ul, .page ol { margin-bottom: 1rem; padding-left: 1.5rem; }
.page li { margin-bottom: 0.3rem; }

.page a {
  color: var(--color-accent);
  text-decoration: underline;
  text-underline-offset: 2px;
}

.page a:hover {
  color: var(--color-accent-hover);
}

/* ========================================
   Table of Contents
   ======================================== */

.article-toc {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 1.25rem 1.5rem;
  margin-bottom: 2.5rem;
}

.article-toc-title {
  font-size: 0.82rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--color-text-light);
  margin-bottom: 0.75rem;
}

.article-toc ol {
  list-style: none;
  padding: 0;
  margin: 0;
}

.article-toc li {
  margin-bottom: 0.35rem;
}

.article-toc a {
  color: var(--color-text-muted);
  text-decoration: none;
  font-size: 0.9rem;
  line-height: 1.5;
  transition: color 0.15s;
}

.article-toc a:hover {
  color: var(--color-accent);
}

/* ========================================
   Responsive: Tablet (640px-1024px)
   ======================================== */

@media (min-width: 640px) {
  .article-list {
    grid-template-columns: repeat(2, 1fr);
  }
}

/* ========================================
   Responsive: Desktop (> 1024px)
   ======================================== */

@media (min-width: 1024px) {
  .article-content {
    font-size: 1.125rem;
  }
}

/* ========================================
   Responsive: Mobile (< 640px)
   ======================================== */

@media (max-width: 639px) {
  body {
    font-size: 16px;
  }

  .article-content {
    font-size: 1rem;
  }

  .article-header h1 {
    font-size: 1.75rem;
  }

  .page h1,
  .page-home h1,
  .articles-page-header h1 {
    font-size: 1.75rem;
  }

  .article-content h2 {
    font-size: 1.4rem;
  }

  .article-content h3 {
    font-size: 1.15rem;
  }

  .header-top {
    margin-bottom: 0.35rem;
    gap: 0.5rem;
  }

  .site-nav {
    flex-wrap: wrap;
    gap: 0.15rem;
  }

  .site-nav a {
    min-height: 44px;
    display: inline-flex;
    align-items: center;
  }

  main {
    padding: 1.5rem 1rem 3rem;
  }

  .site-header {
    padding-left: 1rem;
    padding-right: 1rem;
  }

  .site-footer {
    padding-left: 1rem;
    padding-right: 1rem;
  }

  .article-content pre {
    font-size: 0.8rem;
    padding: 1rem;
    border-radius: 6px;
    margin-left: -1rem;
    margin-right: -1rem;
    border-radius: 0;
  }

  .article-card {
    padding: 1rem 1.15rem;
  }

  .footer-inner {
    flex-direction: column;
    gap: 1rem;
  }

  .footer-links {
    flex-wrap: wrap;
    gap: 1rem;
  }

  .article-toc {
    padding: 1rem 1.15rem;
  }

  .category-nav a {
    min-height: 44px;
  }

  .article-nav {
    flex-direction: column;
    gap: 0.75rem;
  }

  .article-nav a {
    min-height: 44px;
    display: inline-flex;
    align-items: center;
  }
}

/* ========================================
   Print
   ======================================== */

@media print {
  .site-header-wrap,
  .site-footer-wrap,
  .category-nav,
  .article-nav,
  .article-toc {
    display: none;
  }

  main {
    max-width: 100%;
    padding: 0;
  }
}

/* ========================================
   Search
   ======================================== */

.search-box {
  margin-bottom: 1.5rem;
}

.search-box input[type="search"] {
  width: 100%;
  padding: 0.7rem 1rem;
  font-size: 1rem;
  font-family: var(--font-sans);
  color: var(--color-text);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  outline: none;
  transition: border-color 0.15s, box-shadow 0.15s;
  box-shadow: var(--shadow-sm);
}

.search-box input[type="search"]::placeholder {
  color: var(--color-text-light);
}

.search-box input[type="search"]:focus {
  border-color: var(--color-accent);
  box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.15);
}

.article-card.hidden {
  display: none;
}

.category-section.hidden {
  display: none;
}

@media (max-width: 639px) {
  .search-box input[type="search"] {
    font-size: 16px;
  }
}