:root {
  color-scheme: light;
  --color-brand: #44c8f5;
  --color-brand-contrast: #297893;
  --color-brand-soft: rgba(68, 200, 245, 0.18);
  --color-brand-softer: rgba(68, 200, 245, 0.1);
  --color-brand-border: rgba(68, 200, 245, 0.35);
  --color-accent-yellow: #ffff00;
  --color-accent-magenta: #e6007e;
  --color-accent-yellow-soft: rgba(255, 255, 0, 0.22);
  --color-accent-yellow-strong: rgba(255, 255, 0, 0.35);
  --color-accent-magenta-soft: rgba(230, 0, 126, 0.14);
  --color-accent-magenta-border: rgba(230, 0, 126, 0.28);
  --color-bg: #ffffff;
  --color-bg-muted: #f5f5f5;
  --color-surface: #ffffff;
  --color-text: #1a1a1a;
  --color-muted: #4f4f4f;
  --color-border: #e5e7eb;
  --color-primary: var(--color-brand);
  --color-secondary: var(--color-accent-magenta);
  --color-link: #297893;
  --color-link-hover: #1f5a6e;
  /* Softer, non-black code background for light theme */
  --color-code-bg: #f6f8fa;
  --color-code-text: #24292e;
  --focus-ring-shadow: 0 0 0 3px rgba(68, 200, 245, 0.45);
  --shadow: 0 10px 30px rgba(26, 26, 26, 0.08);
  --radius: 12px;
  /* Syntax palette (light) */
  --hljs-keyword: #0d5bd9;      /* blue */
  --hljs-string: #047857;       /* teal/green */
  --hljs-number: #7c3aed;       /* violet */
  --hljs-comment: #6e7781;      /* gray */
  --hljs-type: #b45309;         /* amber/brown */
  --hljs-attr: #e6007e;         /* magenta */
  --hljs-meta: #a37100;         /* brown/orange */
  --hljs-built-in: #dc2626;     /* red */
  --hljs-function: #2563eb;     /* function names (if present) */
}

[data-theme="dark"] {
  color-scheme: dark;
  --color-brand: #44c8f5;
  --color-brand-contrast: #297893;
  --color-brand-soft: rgba(68, 200, 245, 0.3);
  --color-brand-softer: rgba(68, 200, 245, 0.18);
  --color-brand-border: rgba(68, 200, 245, 0.45);
  --color-accent-yellow: #ffff00;
  --color-accent-magenta: #e6007e;
  --color-accent-yellow-soft: rgba(255, 255, 0, 0.28);
  --color-accent-yellow-strong: rgba(255, 255, 0, 0.38);
  --color-accent-magenta-soft: rgba(230, 0, 126, 0.22);
  --color-accent-magenta-border: rgba(230, 0, 126, 0.35);
  --color-bg: #090909;
  --color-bg-muted: #131313;
  --color-surface: #121212;
  --color-text: #f5f5f5;
  --color-muted: #c7c7c7;
  --color-border: #333333;
  --color-primary: var(--color-brand);
  --color-secondary: var(--color-accent-magenta);
  --color-link: #44c8f5;
  --color-link-hover: #22b7ee;
  /* Softer, non-black code background for dark theme */
  --color-code-bg: #1e1e1e;
  --color-code-text: #f5f5f5;
  --focus-ring-shadow: 0 0 0 3px rgba(68, 200, 245, 0.6);
  --shadow: 0 10px 30px rgba(0, 0, 0, 0.35);
  /* Syntax palette (dark) */
  --hljs-keyword: #7aa2f7;      /* soft blue */
  --hljs-string: #9ece6a;       /* green */
  --hljs-number: #bb9af7;       /* purple */
  --hljs-comment: #9aa4b2;      /* gray */
  --hljs-type: #e0af68;         /* gold */
  --hljs-attr: #f7768e;         /* pink */
  --hljs-meta: #ff9e64;         /* orange */
  --hljs-built-in: #f43f5e;     /* red */
  --hljs-function: #7aa2f7;     /* function names (if present) */
}

* {
  box-sizing: border-box;
}

html, body {
  margin: 0;
  padding: 0;
  font-family: "Inter", system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  background: var(--color-bg);
  color: var(--color-text);
  min-height: 100%;
}

body {
  display: flex;
}

.page {
  display: grid;
  grid-template-columns: 280px 1fr;
  width: 100%;
  min-height: 100vh;
}

.sidebar {
  background: linear-gradient(180deg, var(--color-brand-softer) 0%, var(--color-bg) 75%);
  border-right: 1px solid var(--color-brand-border);
  padding: 2rem 1.5rem;
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
  position: sticky;
  top: 0;
  max-height: 100vh;
  overflow-y: auto;
}

.brand-title {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--color-link);
}

.brand-subtitle {
  color: var(--color-link-hover);
  margin: 0.2rem 0 0;
}

.toc {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
}

.toc > li > a,
.toc ul a {
  display: flex;
  align-items: center;
  gap: 0.55rem;
  padding: 0.35rem 0.5rem;
  border-radius: 8px;
  text-decoration: none;
  font-weight: 500;
  box-shadow: inset 3px 0 0 transparent;
}

.toc > li > a {
  color: var(--color-link);
}

.toc > li > a:hover,
.toc > li > a.active {
  background: var(--color-accent-yellow-soft);
  color: var(--color-link-hover);
  box-shadow: inset 3px 0 0 var(--color-accent-yellow);
}

.toc ul {
  list-style: none;
  padding: 0 0 0 0.75rem;
  margin: 0.3rem 0 0;
  display: flex;
  flex-direction: column;
  gap: 0.3rem;
}

.toc ul a {
  color: var(--color-link);
  font-size: 0.95rem;
  border-radius: 8px;
}

.toc ul a:hover,
.toc ul a.active {
  background: var(--color-accent-yellow-soft);
  color: var(--color-link-hover);
  box-shadow: inset 3px 0 0 var(--color-accent-yellow);
}

.icon,
.heading-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
}

.icon {
  width: 1.35rem;
  height: 1.35rem;
}

.icon svg,
.heading-icon svg {
  width: 100%;
  height: 100%;
}

.sidebar .icon {
  color: var(--color-muted);
}

.sidebar a:hover .icon,
.sidebar a.active .icon {
  color: var(--color-link-hover);
}

.toc ul a .icon {
  width: 1.15rem;
  height: 1.15rem;
}

.title-with-icon {
  display: flex;
  align-items: center;
  gap: 0.65rem;
}

.heading-icon {
  width: 1.85rem;
  height: 1.85rem;
  border-radius: 50%;
  background: var(--color-brand-softer);
  color: var(--color-link);
}

[data-theme="dark"] .heading-icon {
  background: var(--color-brand-soft);
}

[data-theme="dark"] .sidebar {
  background: linear-gradient(180deg, var(--color-brand-soft) 0%, var(--color-surface) 75%);
  border-right-color: var(--color-brand-border);
}

.title-with-icon .heading-icon svg {
  width: 1.1rem;
  height: 1.1rem;
}

.toc-text {
  flex: 1;
}

#content {
  background: transparent;
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

.page-header {
  position: sticky;
  top: 0;
  z-index: 10;
  background: rgba(255, 255, 255, 0.85);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--color-border);
  padding: 1rem 2rem;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

[data-theme="dark"] .page-header {
  background: rgba(9, 9, 9, 0.85);
}

.header-tools {
  display: flex;
  gap: 0.75rem;
  align-items: center;
}

#search {
  width: 280px;
  max-width: 100%;
  padding: 0.55rem 0.75rem;
  border-radius: 10px;
  border: 1px solid var(--color-border);
  background: var(--color-surface);
  color: var(--color-text);
  transition: box-shadow 0.2s ease;
}

#search:focus {
  outline: none;
  box-shadow: var(--focus-ring-shadow);
}

#theme-toggle {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: 999px;
  padding: 0.5rem 0.75rem;
  cursor: pointer;
  font-size: 1.1rem;
  line-height: 1;
  transition: transform 0.2s ease;
}

#theme-toggle:hover {
  transform: translateY(-1px);
}

#theme-toggle:focus-visible,
button.copy-btn:focus-visible {
  outline: 2px solid var(--color-link);
  outline-offset: 2px;
}

#search-results {
  display: none;
  max-height: 300px;
  overflow-y: auto;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

#search-results.visible {
  display: block;
}

#search-results button {
  width: 100%;
  text-align: left;
  padding: 0.6rem 0.75rem;
  border: none;
  background: transparent;
  color: var(--color-text);
  cursor: pointer;
}

#search-results button:hover,
#search-results button:focus {
  background: var(--color-brand-softer);
}

article {
  padding: 2rem 3rem 4rem;
  display: flex;
  flex-direction: column;
  gap: 3.5rem;
}

section {
  background: var(--color-surface);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 2rem;
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

section section {
  box-shadow: none;
  padding: 1.5rem;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
}

h2, h3, h4 {
  margin: 0;
  font-weight: 600;
}

h2 {
  font-size: 2rem;
}

h3 {
  font-size: 1.35rem;
}

h4 {
  font-size: 1.1rem;
}

p, li {
  line-height: 1.6;
  color: var(--color-text);
}

strong {
  color: var(--color-text);
}

a {
  color: var(--color-link);
}

a:hover,
a:focus {
  color: var(--color-link-hover);
}

a:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}

.two-column,
.info-grid,
.code-grid,
.quickstart-grid,
.two-page {
  display: grid;
  gap: 1.5rem;
}

.two-column {
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
}

.two-page {
  grid-template-columns: 1fr; /* Stack articles vertically for more width per diagram */
  gap: 2.25rem; /* More breathing room between subsections */
}

.two-page article > p {
  margin: 0 0 0.5rem; /* tighter spacing above diagrams */
}

.two-page article > figure,
.two-page article > ol {
  margin-top: 0;
}

.two-page article > figure {
  margin-bottom: 0.9rem;
}

.two-page article > ol {
  margin-bottom: 0.6rem; /* tighter spacing above diagrams */
  padding-left: 1.1rem;
}

/* Reduce heading spacing within two-page section */
.two-page h3.title-with-icon,
.two-page h3 {
  margin-bottom: 0.5rem;
}

.quickstart-grid {
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
}

.info-grid {
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
}

.code-grid {
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
}

.folder-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 1rem;
}

.folder-card {
  background: var(--color-brand-softer);
  border-radius: var(--radius);
  padding: 1rem 1.2rem;
  border: 1px solid var(--color-brand-border);
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
}

[data-theme="dark"] .folder-card {
  background: var(--color-brand-soft);
  border-color: var(--color-brand-border);
}

.folder-card h4 {
  margin: 0;
  font-size: 1rem;
}

.folder-card p {
  margin: 0;
  color: var(--color-muted);
}

.keyword-cheat {
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 1.5rem;
  background: var(--color-brand-softer);
}

.keyword-grid .folder-card {
  background: var(--color-brand-soft);
  border-color: var(--color-brand-border);
}

[data-theme="dark"] .keyword-grid .folder-card {
  background: var(--color-brand-soft);
  border-color: var(--color-brand-border);
}

.keyword-cheat .folder-card h4 {
  font-size: 1rem;
}

pre {
  background: var(--color-code-bg);
  color: var(--color-code-text);
  padding: 1rem;
  border-radius: 10px;
  overflow-x: auto;
  font-family: "Source Code Pro", SFMono-Regular, Consolas, "Liberation Mono", Menlo, monospace;
  font-size: 0.9rem;
  position: relative;
}

pre code.hljs {
  display: block;
  background: transparent;
  color: inherit;
}

pre code.hljs .hljs-keyword {
  color: var(--hljs-keyword);
}

pre code.hljs .hljs-built_in {
  color: var(--hljs-built-in);
}

pre code.hljs .hljs-meta {
  color: var(--hljs-meta);
}

pre code.hljs .hljs-selector-tag {
  color: var(--hljs-type);
}

pre code.hljs .hljs-string,
pre code.hljs .hljs-title.class_,
pre code.hljs .hljs-title.function_ {
  color: var(--hljs-string);
}

pre code.hljs .hljs-title.function_ {
  color: var(--hljs-function);
}

pre code.hljs .hljs-number,
pre code.hljs .hljs-literal,
pre code.hljs .hljs-symbol,
pre code.hljs .hljs-variable.constant_ {
  color: var(--hljs-number);
}

pre code.hljs .hljs-comment,
pre code.hljs .hljs-quote,
pre code.hljs .hljs-code {
  color: var(--hljs-comment);
  font-style: italic;
}

pre code.hljs .hljs-type,
pre code.hljs .hljs-built_in-name,
pre code.hljs .hljs-selector-class,
pre code.hljs .hljs-selector-id {
  color: var(--hljs-type);
}

pre code.hljs .hljs-attr,
pre code.hljs .hljs-attribute,
pre code.hljs .hljs-name {
  color: var(--hljs-attr);
}

.code-sample {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.code-sample figcaption {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--color-muted);
}

.diagram {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.diagram .mermaid {
  background: var(--color-brand-softer);
  border: 1px solid var(--color-brand-border);
  border-radius: 12px;
  padding: 1rem;
  display: flex;
  justify-content: center;
}

.diagram .mermaid svg {
  display: block;
  margin: 0 auto;
  max-width: 100%;
  height: auto;
}

/* Optional taller variant for specific diagrams */
.mermaid.tall {
  min-height: 260px;
}

.mini-diagram {
  margin: 0 0 1rem;
}

.mini-diagram .mermaid {
  border-radius: 10px;
  background: var(--color-brand-softer);
  border: 1px solid var(--color-brand-border);
  display: flex;
  justify-content: center;
}

.mini-diagram .mermaid svg {
  display: block;
  margin: 0 auto;
  max-width: 100%;
  height: auto;
}

/* Refined heading style for Ports & Adapters subsections */
.two-page h3 {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.35rem 0.6rem;
  border-left: 8px solid var(--color-brand) !important;
  border-radius: 6px;
  background: var(--color-brand-softer);
  color: var(--color-text);
  line-height: 1.2;
}

#ports-adapters article h3 {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.35rem 0.6rem;
  border-left: 6px solid var(--color-brand);
  border-radius: 8px;
  background: var(--color-brand-softer);
  color: var(--color-text);
  line-height: 1.2;
}

.callout {
  border-radius: var(--radius);
  border-left: 6px solid var(--color-accent-magenta) !important;
  padding: 1rem 1.25rem;
  background: var(--color-brand-soft);
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.callout h4 {
  margin: 0;
}

.callout.why {
  border-left-color: var(--color-secondary);
  background: var(--color-accent-magenta-soft);
}

.callout.who {
  border-left-color: var(--color-brand-contrast);
  background: var(--color-brand-softer);
}

.callout.try {
  border-left-color: var(--color-secondary);
  background: var(--color-accent-magenta-soft);
}

.callout.watchout {
  border-left-color: var(--color-accent-yellow) !important;
  background: var(--color-accent-yellow-soft);
  color: var(--color-text);
}

.callout.concept {
  border-left-color: var(--color-secondary);
  background: var(--color-accent-magenta-soft);
}

.quickstart {
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 1.5rem;
  background: var(--color-brand-softer);
}

.quickstart .code-grid {
  margin-top: 1.5rem;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
}

.quickstart pre {
  background: var(--color-code-bg);
  color: var(--color-code-text);
}

.rules {
  border-radius: var(--radius);
  padding: 1.5rem;
  background: linear-gradient(135deg, var(--color-brand-softer), var(--color-accent-magenta-soft));
  border: 1px solid var(--color-brand-border);
  display: grid;
  gap: 1.25rem;
  box-shadow: 0 12px 35px rgba(26, 26, 26, 0.12);
}

.rules h3 {
  font-size: 1.1rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.rules ul {
  margin: 0;
  padding-left: 1.2rem;
  display: grid;
  gap: 0.4rem;
}

.rules ul li::marker {
  color: var(--color-link);
}

.quickstart h3 {
  margin-bottom: 0.5rem;
}

.checklist {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  flex-direction: column;
  gap: 0.6rem;
}

.checklist li {
  display: flex;
  align-items: center;
  gap: 0.6rem;
}

.checklist input[type="checkbox"] {
  accent-color: var(--color-primary);
  width: 1rem;
  height: 1rem;
}

.glossary {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 1rem;
}

.term {
  background: var(--color-brand-softer);
  border: 1px solid var(--color-brand-border);
  border-radius: var(--radius);
  padding: 1rem;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.term:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow);
}

.term h4 {
  margin: 0;
  font-size: 1.1rem;
  color: var(--color-link);
  font-weight: 600;
}

.term p {
  margin: 0;
  color: var(--color-muted);
  line-height: 1.5;
}

[data-theme="dark"] .term {
  background: var(--color-brand-soft);
  border-color: var(--color-brand-border);
}

.back-to-top {
  text-align: right;
}

.back-to-top a {
  text-decoration: none;
  color: var(--color-link);
  font-weight: 600;
}

button.copy-btn {
  position: absolute;
  top: 0.6rem;
  right: 0.6rem;
  border: 1px solid var(--color-border);
  background: var(--color-bg-muted);
  color: var(--color-text);
  font-size: 0.75rem;
  border-radius: 6px;
  padding: 0.2rem 0.45rem;
  cursor: pointer;
  transition: background 0.2s ease;
}

button.copy-btn:hover {
  background: var(--color-brand-contrast);
  color: #ffffff;
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  border: 0;
}

@media (max-width: 1100px) {
  .page {
    grid-template-columns: 1fr;
  }

  .sidebar {
    position: relative;
    max-height: none;
    flex-direction: row;
    flex-wrap: wrap;
    gap: 1rem 2rem;
  }

  .toc {
    flex-direction: row;
    flex-wrap: wrap;
    gap: 0.5rem 1rem;
  }

  .toc ul {
    display: none;
  }

  article {
    padding: 2rem 1.5rem 4rem;
  }
}

@media (max-width: 700px) {
  .page-header {
    padding: 0.75rem 1.25rem;
  }

  #search {
    width: 100%;
  }

  .header-tools {
    flex-direction: column;
    align-items: stretch;
  }

  section {
    padding: 1.5rem;
  }
}
.usecase-facets {
  list-style: none;
  padding: 0;
  margin: 0;
  display: grid;
  gap: 0.6rem;
}

.usecase-facets li {
  display: flex;
  align-items: center;
  gap: 0.6rem;
}

.facet-icon {
  font-size: 1.1rem;
}
.toc .icon svg {
  width: 1.1rem;
  height: 1.1rem;
}
.highlight {
  background: linear-gradient(120deg, var(--color-accent-yellow-strong), var(--color-accent-yellow-soft));
  padding: 0.05rem 0.35rem;
  border-radius: 6px;
  color: var(--color-text);
}

.accordion {
    display: flex;
    flex-direction: column;
}

.accordion-item {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius);
    transition: box-shadow 0.2s ease, background-color 0.2s ease;
    box-shadow: 0 1px 3px rgba(0,0,0,0.05);
    margin-bottom: 1.5rem;
}

.accordion-item:last-child {
    margin-bottom: 0;
}

.accordion-item:hover {
    border-color: var(--color-brand-border);
}

.accordion-item.active {
    background: var(--color-surface);
    box-shadow: 0 4px 12px rgba(0,0,0,0.1);
    border-color: var(--color-brand);
}

.accordion-question {
    width: 100%;
    background: transparent;
    border: none;
    padding: 1.25rem 1.5rem;
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--color-link);
    text-align: left;
    cursor: pointer;
    display: flex;
    align-items: center;
    white-space: normal;
    overflow-wrap: break-word;
    transition: background-color 0.2s ease;
}

.accordion-question:hover {
    background-color: var(--color-bg-muted);
}

.accordion-item.active .accordion-question {
    background-color: var(--color-brand-softer);
    color: var(--color-brand-contrast);
}

.accordion-question::before {
    content: '›';
    font-size: 1.8rem;
    color: var(--color-muted);
    transition: transform 0.3s ease;
    margin-right: 1rem;
    flex-shrink: 0;
    transform-origin: center;
    line-height: 1;
}

.accordion-item.active .accordion-question::before {
    transform: rotate(90deg);
    color: var(--color-brand-contrast);
}

.accordion-answer {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease-in-out;
    padding: 0 1.5rem;
    color: var(--color-muted);
}

.accordion-item.active .accordion-answer {
    padding-bottom: 1.5rem;
}

.accordion-answer ul {
    padding-left: 1.2rem;
}

.accordion-answer li {
    margin-bottom: 0.5rem;
}

.accordion-question code {
  font-family: inherit;
  color: var(--color-brand);
  background-color: var(--color-brand-softer);
  padding: 0.2em 0.4em;
  border-radius: 4px;
  font-weight: 600;
}

.accordion-answer code {
  font-family: inherit;
  background-color: var(--color-bg-muted);
  color: var(--color-brand-contrast);
  padding: 0.2em 0.4em;
  border-radius: 4px;
  font-size: 0.9em;
}