:root {
  /* Font Families */
  --font-heading: 'Newsreader', serif;
  --font-body: 'Manrope', sans-serif;
  --font-metadata: var(--font-body);
  --font-ui: var(--font-body);

  /* Font Weights */
  --weight-regular: 400;
  --weight-medium: 500;
  --weight-bold: 700;

  /* Line Heights */
  --lh-body: 1.6;
  --lh-heading: 1.2;

  /* Light Mode Base Variables */
  --bg-color: #f8f9fa;
  --text-color: #212529;
  --metadata-text-color: #6c757d;

  /* Link Interactions */
  --link-color: inherit;
  --link-hover-color: #10b981; /* Emerald green */
}

:root[data-theme='dark'] {
  --bg-color: #121212;
  --text-color: #f8f9fa;
  --metadata-text-color: #adb5bd;
  --link-hover-color: #34d399; /* Higher contrast emerald */
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme='light']) {
    --bg-color: #121212;
    --text-color: #f8f9fa;
    --metadata-text-color: #adb5bd;
    --link-hover-color: #34d399; /* Higher contrast emerald */
  }
}

:root[data-theme='dark'] {
  --bg-color: #121212;
  --text-color: #f8f9fa;
  --metadata-text-color: #adb5bd;
  --link-hover-color: #34d399;
}

:root[data-theme='light'] {
  --bg-color: #f8f9fa;
  --text-color: #212529;
  --metadata-text-color: #6c757d;
  --link-hover-color: #10b981;
}

/* Global Elements */
html {
  font-size: clamp(16px, 0.6vw + 12px, 18px);
  scroll-behavior: smooth;
  scroll-padding-top: 5rem;
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
}

body {
  background-color: var(--bg-color);
  color: var(--text-color);
  font-family: var(--font-body);
  line-height: var(--lh-body);
  margin: 0;
  padding: 0;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

main {
  flex: 1;
}

h1,
h2,
h3,
h4,
h5,
h6 {
  font-family: var(--font-heading);
  line-height: var(--lh-heading);
  color: var(--text-color);
}

a {
  color: var(--link-color);
  text-decoration: underline;
  transition: color 0.2s ease-in-out;
}

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

.metadata {
  color: var(--metadata-text-color);
  font-family: var(--font-metadata);
  font-size: 0.9rem;
}

/* Layout Utilities */
.container {
  max-width: 72ch;
  margin: 0 auto;
  padding: 5rem 1.5rem;
}

@media (max-width: 768px) {
  .container {
    padding: 5rem 1.25rem;
  }
}

/* Top Navigation & Theme Toggle */
.top-nav {
  position: fixed;
  top: 1.5rem;
  right: 1.5rem;
  z-index: 1000;
  display: flex;
  align-items: center;
  gap: 1.5rem;
}

.nav-link {
  font-family: var(--font-ui);
  text-decoration: none;
  font-size: 0.9rem;
  color: var(--text-color);
  opacity: 0.6;
  transition:
    opacity 0.2s ease,
    color 0.2s ease;
}

.nav-link:hover {
  opacity: 1;
  color: var(--link-hover-color);
}

.theme-toggle {
  background: none;
  border: none;
  padding: 0.5rem;
  cursor: pointer;
  color: var(--text-color);
  display: flex;
  align-items: center;
  justify-content: center;
  transition:
    color 0.2s ease,
    transform 0.2s ease;
  opacity: 0.6;
}

.theme-toggle:hover {
  opacity: 1;
  transform: scale(1.1);
  color: var(--link-hover-color);
}

.sun-icon,
.moon-icon {
  width: 22px;
  height: 22px;
  fill: none;
  stroke: currentColor;
  stroke-width: 2;
  stroke-linecap: round;
  stroke-linejoin: round;
}

:root[data-theme='dark'] .moon-icon {
  display: none;
}
:root[data-theme='dark'] .sun-icon {
  display: block;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme='light']) .moon-icon {
    display: none;
  }
  :root:not([data-theme='light']) .sun-icon {
    display: block;
  }
}

:root[data-theme='light'] .sun-icon {
  display: none;
}
:root[data-theme='light'] .moon-icon {
  display: block;
}
@media (prefers-color-scheme: light) {
  :root:not([data-theme='dark']) .sun-icon {
    display: none;
  }
  :root:not([data-theme='dark']) .moon-icon {
    display: block;
  }
}

/* Article Layout & Sidebar */
.article-layout {
  display: grid;
  grid-template-columns: 1fr minmax(0, 90ch) 1fr;
  gap: 4rem;
  align-items: start;
  max-width: 1600px;
  margin: 0 auto;
  padding: 5rem 2rem;
}

.article-layout header,
.article-layout .content,
.article-layout .article-footer {
  grid-column: 2;
  width: 100%;
}

.article-layout .content {
  max-width: 72ch;
  margin: 0 auto;
  font-size: 1.125rem;
}

.article-layout .article-footer {
  padding-top: 2rem;
  border-top: 1px solid var(--metadata-text-color);
  font-family: var(--font-ui);
  font-size: 0.9rem;
}

.article-layout.no-toc {
  display: flex;
  flex-direction: column;
  align-items: center;
}

.article-layout.no-toc header,
.article-layout.no-toc .content,
.article-layout.no-toc .article-footer {
  max-width: 90ch;
}

.article-layout.no-toc .content {
  max-width: 72ch;
}

.toc-sidebar {
  grid-column: 1;
  justify-self: end;
  width: 240px;
  position: sticky;
  top: 4rem;
  align-self: start;
}

.toc-sticky-container {
  max-height: calc(100vh - 4rem);
  overflow-y: auto;
  overflow-x: hidden;
  padding-right: 1rem;
}

.toc-sidebar h2 {
  font-size: 0.8rem;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--metadata-text-color);
  margin-bottom: 1.5rem;
  font-family: var(--font-ui);
}

#TableOfContents ul,
#TableOfContents ol {
  counter-reset: toc;
  list-style: none !important;
  padding-left: 0;
}

#TableOfContents ul ul,
#TableOfContents ol ol {
  padding-left: 1.5rem;
  margin-top: 0.5rem;
}

#TableOfContents li {
  counter-increment: toc;
  margin-bottom: 0.75rem;
  font-size: 0.9rem;
  list-style: none !important;
}

#TableOfContents a::before {
  content: counters(toc, '.') '. ';
  margin-right: 0.5rem;
  font-variant-numeric: tabular-nums;
  opacity: 0.5;
  flex-shrink: 0;
  min-width: 1.25rem;
}

#TableOfContents li a {
  text-decoration: none;
  font-family: var(--font-ui);
  color: var(--text-color);
  opacity: 0.5;
  transition: all 0.25s ease;
  line-height: 1.4;
  display: flex;
  align-items: flex-start;
}

#TableOfContents li a.active {
  opacity: 1;
  color: var(--link-hover-color);
  font-weight: 700;
  transform: translateX(4px);
}

#TableOfContents li a:hover {
  opacity: 1;
  color: var(--link-hover-color);
}

/* Responsiveness */
@media (max-width: 1200px) {
  .article-layout {
    grid-template-columns: 1fr;
    display: block;
    padding: 5rem 1.5rem 2rem 1.5rem;
  }

  .toc-sidebar {
    width: 100%;
    max-width: 72ch;
    margin: 0 auto 2rem auto;
    box-sizing: border-box;
    background: var(--bg-color);
    border-radius: 8px;
    padding: 1.5rem;
    border: 1px solid var(--metadata-text-color);
    position: static;
  }

  .toc-sticky-container {
    position: static;
    max-height: none;
  }
}

.mobile-toc-toggle,
.mobile-toc-overlay {
  display: none;
}

@media (max-width: 768px) {
  .top-nav {
    top: 1rem;
    right: 1rem;
    gap: 1rem;
  }

  .toc-sidebar {
    display: none;
  }

  .mobile-toc-toggle {
    display: flex;
    position: fixed;
    bottom: 2rem;
    right: 1.5rem;
    width: 3.5rem;
    height: 3.5rem;
    background: var(--bg-color);
    border: 1px solid var(--metadata-text-color);
    border-radius: 50%;
    z-index: 1001;
    align-items: center;
    justify-content: center;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
    cursor: pointer;
    color: var(--text-color);
  }

  .mobile-toc-overlay {
    position: fixed;
    inset: 0;
    background: var(--bg-color);
    z-index: 2000;
    padding: 2rem;
    display: none;
    flex-direction: column;
    overflow-y: auto;
  }

  .mobile-toc-overlay.active {
    display: flex;
  }

  .mobile-toc-overlay .close-button {
    align-self: flex-end;
    background: none;
    border: none;
    font-size: 2rem;
    cursor: pointer;
    color: var(--text-color);
    margin-bottom: 2rem;
  }

  .mobile-toc-overlay #TableOfContents {
    margin-top: 1rem;
  }
}

/* Further Reading */
.further-reading {
  grid-column: 2;
  margin-top: 4rem;
  margin-bottom: 2rem;
  width: 100%;
  max-width: 900px;
  margin-left: auto;
  margin-right: auto;
}

.further-reading-title {
  text-align: center;
  font-family: var(--font-heading);
  font-size: 2rem;
  color: var(--text-color);
  margin-bottom: 2rem;
  font-weight: 500;
}

.further-reading-grid {
  display: flex;
  justify-content: space-between;
  gap: 2rem;
}

.further-reading-prev,
.further-reading-next {
  flex: 1;
  display: flex;
  flex-direction: column;
}

.further-reading-prev {
  text-align: left;
}

.further-reading-next {
  text-align: right;
  align-items: flex-end;
}

.further-reading-label {
  font-family: var(--font-ui);
  font-size: 0.9rem;
  color: var(--link-hover-color);
  margin-bottom: 1rem;
}

.further-reading a {
  text-decoration: none;
  color: inherit;
  display: block;
}

.further-reading a:hover {
  color: var(--text-color);
}

.further-reading a:hover .post-title {
  text-decoration: underline;
  text-decoration-color: var(--link-hover-color);
}

.further-reading .post-title {
  font-family: var(--font-heading);
  font-size: 2rem;
  line-height: var(--lh-heading);
  margin: 0 0 1rem 0;
  color: var(--text-color);
}

@media (max-width: 768px) {
  .further-reading-grid {
    flex-direction: column;
    gap: 3rem;
  }

  .further-reading-prev,
  .further-reading-next {
    text-align: center;
    align-items: center;
  }
}