/* ==========================================================================
   CSS Custom Properties (T010)
   ========================================================================== */

:root {
  /* Colors - Light Theme */
  --color-bg: #FDFBF7;
  --color-text: #2D2D2D;
  --color-text-secondary: #5C5C5C;
  --color-accent: #D2691E;
  --color-accent-hover: #A0520F;
  --color-border: #E8E4DF;

  /* Typography */
  --font-family: 'Roboto Slab', Georgia, serif;
  --font-size-base: 18px;
  --line-height: 1.6;
  --type-scale: 1.25;

  /* Spacing */
  --space-xs: 0.5rem;
  --space-sm: 1rem;
  --space-md: 1.5rem;
  --space-lg: 2rem;
  --space-xl: 3rem;

  /* Layout */
  --max-width: 42rem;
  --nav-height: 4rem;

  /* Animation Properties */
  --animation-typing-speed: 50ms;
  --animation-cursor-blink: 1s;
  --animation-ease-typing: steps(1, end);

  /* Texture Properties */
  --texture-opacity: 0.015;
  --gradient-opacity: 0.008;
  --texture-size: 12px;
}

/* ==========================================================================
   Dark Theme (T060)
   ========================================================================== */

[data-theme="dark"] {
  --color-bg: #1a1a1a;
  --color-text: #E0DCD7;
  --color-text-secondary: #A09A93;
  --color-accent: #E8923A;
  --color-accent-hover: #F0A85C;
  --color-border: #333330;
  --texture-opacity: 0.008;
  --gradient-opacity: 0.004;
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --color-bg: #1a1a1a;
    --color-text: #E0DCD7;
    --color-text-secondary: #A09A93;
    --color-accent: #E8923A;
    --color-accent-hover: #F0A85C;
    --color-border: #333330;
    --texture-opacity: 0.008;
    --gradient-opacity: 0.004;
  }
}

/* Dark mode toggle button */
.theme-toggle {
  background: none;
  border: 1px solid var(--color-border);
  border-radius: 4px;
  padding: 0.35rem 0.5rem;
  cursor: pointer;
  color: var(--color-text);
  font-size: 1rem;
  line-height: 1;
  transition: border-color 0.2s, color 0.2s;
  display: flex;
  align-items: center;
}

.theme-toggle:hover {
  border-color: var(--color-accent);
  color: var(--color-accent);
}

/* Dark mode overrides for hardcoded colors */
[data-theme="dark"] .post-content blockquote {
  background-color: rgba(255, 255, 255, 0.03);
}

[data-theme="dark"] .post-content p code {
  background-color: rgba(255, 255, 255, 0.08);
}

[data-theme="dark"] .site-header::after {
  background: linear-gradient(
    to right,
    rgba(26, 26, 26, 0.8),
    rgba(232, 146, 58, var(--gradient-opacity)) 50%,
    rgba(26, 26, 26, 0.8)
  );
}

[data-theme="dark"] .search-results {
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.4);
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) .post-content blockquote {
    background-color: rgba(255, 255, 255, 0.03);
  }
  :root:not([data-theme="light"]) .post-content p code {
    background-color: rgba(255, 255, 255, 0.08);
  }
  :root:not([data-theme="light"]) .site-header::after {
    background: linear-gradient(
      to right,
      rgba(26, 26, 26, 0.8),
      rgba(232, 146, 58, var(--gradient-opacity)) 50%,
      rgba(26, 26, 26, 0.8)
    );
  }
  :root:not([data-theme="light"]) .search-results {
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.4);
  }
}

/* ==========================================================================
   Base Styles & Typography (T011)
   ========================================================================== */

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

html {
  font-size: var(--font-size-base);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  margin: 0;
  font-family: var(--font-family);
  font-size: 1rem;
  line-height: var(--line-height);
  color: var(--color-text);
  background-color: var(--color-bg);
}

/* Headings - lowercase by default */
h1, h2, h3, h4, h5, h6 {
  margin: var(--space-lg) 0 var(--space-sm);
  font-weight: 700;
  line-height: 1.2;
  text-transform: lowercase;
}

h1 { font-size: calc(1rem * var(--type-scale) * var(--type-scale) * var(--type-scale)); }
h2 { font-size: calc(1rem * var(--type-scale) * var(--type-scale)); }
h3 { font-size: calc(1rem * var(--type-scale)); }
h4 { font-size: 1rem; }

p {
  margin: 0 0 var(--space-md);
}

a {
  color: var(--color-accent);
  text-decoration: none;
  transition: color 0.2s ease;
}

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

/* ==========================================================================
   Hero Physics Banner
   ========================================================================== */

.hero-physics {
  width: 100vw;
  height: 150px;
  overflow: hidden;
  position: relative;
  background: var(--color-bg);
  margin-left: calc(-50vw + 50%);
  margin-bottom: var(--space-lg);
}

.hero-physics canvas {
  display: block;
  width: 100%;
  height: 100%;
}

@media (max-width: 480px) {
  .hero-physics {
    height: 100px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .hero-physics canvas {
    animation: none;
  }
}

/* ==========================================================================
   Layout (T012 - Responsive)
   ========================================================================== */

main {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: var(--space-lg) var(--space-md);
  min-height: calc(100vh - var(--nav-height) - 8rem);
}

/* Navigation */
.site-header {
  border-bottom: 1px solid var(--color-border);
}

.nav {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: var(--space-sm) var(--space-md);
  display: flex;
  justify-content: space-between;
  align-items: center;
  height: var(--nav-height);
}

.nav-logo {
  font-weight: 700;
  font-size: 1.25rem;
  text-transform: lowercase;
}

/* Typewriter logo in navigation */
.nav-logo {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 1.25rem;
  font-weight: 700;
  text-transform: none;
  min-height: auto;
}

.nav-links {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  gap: var(--space-md);
}

.nav-links a {
  color: var(--color-text);
  text-transform: lowercase;
}

.nav-links a:hover,
.nav-links a[aria-current="page"] {
  color: var(--color-accent);
}

/* Footer */
.site-footer {
  border-top: 1px solid var(--color-border);
  padding: var(--space-lg) var(--space-md);
  text-align: center;
  color: var(--color-text-secondary);
}

.footer-content {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-sm);
}

.footer-content p {
  margin: 0;
  font-size: 0.9rem;
}

.footer-links {
  display: flex;
  gap: var(--space-md);
  align-items: center;
}

.footer-links a {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  color: var(--color-text-secondary);
  text-decoration: none;
  font-size: 0.9rem;
  transition: color 0.2s ease;
  padding: 0.25rem 0.5rem;
  border-radius: 4px;
}

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

.footer-links svg {
  flex-shrink: 0;
}

@media (min-width: 480px) {
  .footer-content {
    flex-direction: row;
    justify-content: space-between;
    align-items: center;
  }
}

/* ==========================================================================
   Responsive Breakpoints (T012)
   ========================================================================== */

/* Mobile (default) */
@media (max-width: 480px) {
  :root {
    --font-size-base: 16px;
  }

  .nav {
    flex-direction: column;
    height: auto;
    padding: var(--space-sm);
    gap: var(--space-sm);
  }

  .nav-links {
    gap: var(--space-sm);
  }
}

/* Tablet */
@media (min-width: 481px) and (max-width: 768px) {
  :root {
    --font-size-base: 17px;
  }
}

/* Desktop (768px+) uses default values */

/* ==========================================================================
   Post Styles (T018)
   ========================================================================== */

.post-header {
  margin-bottom: var(--space-xl);
}

.post-header h1 {
  margin-top: 0;
  margin-bottom: var(--space-sm);
}

.post-meta {
  color: var(--color-text-secondary);
  font-size: 0.9rem;
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-sm);
  align-items: center;
}

.post-tags {
  display: flex;
  gap: var(--space-xs);
  flex-wrap: wrap;
}

.tag {
  background-color: var(--color-border);
  padding: 0.2em 0.6em;
  border-radius: 3px;
  font-size: 0.85rem;
  text-transform: lowercase;
}

.tag:hover {
  background-color: var(--color-accent);
  color: var(--color-bg);
}

/* Post Content */
.post-content {
  line-height: var(--line-height);
}

.post-content h2,
.post-content h3,
.post-content h4 {
  margin-top: var(--space-xl);
}

.post-content ul,
.post-content ol {
  margin: 0 0 var(--space-md);
  padding-left: var(--space-lg);
}

.post-content li {
  margin-bottom: var(--space-xs);
}

.post-content blockquote {
  margin: var(--space-md) 0;
  padding: var(--space-sm) var(--space-md);
  border-left: 3px solid var(--color-accent);
  background-color: rgba(0, 0, 0, 0.02);
  font-style: italic;
}

.post-content pre {
  margin: var(--space-md) 0;
  padding: var(--space-md);
  background-color: #1a1a1a;
  color: #f5f5f5;
  border-radius: 4px;
  overflow-x: auto;
  font-family: 'SF Mono', Monaco, Consolas, monospace;
  font-size: 0.9rem;
  line-height: 1.4;
}

[data-theme="dark"] .post-content pre {
  background-color: #111;
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) .post-content pre {
    background-color: #111;
  }
}

.post-content code {
  font-family: 'SF Mono', Monaco, Consolas, monospace;
  font-size: 0.9em;
}

.post-content p code {
  background-color: rgba(0, 0, 0, 0.05);
  padding: 0.2em 0.4em;
  border-radius: 3px;
}

.post-content img {
  max-width: 100%;
  height: auto;
  display: block;
  margin: var(--space-md) 0;
}

.post-content hr {
  border: none;
  border-top: 1px solid var(--color-border);
  margin: var(--space-xl) 0;
}

/* ==========================================================================
   Homepage Styles (T023)
   ========================================================================== */

.home .intro {
  font-size: 1.1rem;
  color: var(--color-text-secondary);
  margin-bottom: var(--space-xl);
}

.post-list h2 {
  margin-top: 0;
  border-bottom: 1px solid var(--color-border);
  padding-bottom: var(--space-sm);
}

.post-preview {
  margin-bottom: var(--space-xl);
  padding-bottom: var(--space-lg);
  border-bottom: 1px solid var(--color-border);
}

.post-preview:last-child {
  border-bottom: none;
}

.post-preview h3 {
  margin: 0 0 var(--space-xs);
  font-size: calc(1rem * var(--type-scale));
}

.post-preview h3 a {
  color: var(--color-text);
}

.post-preview h3 a:hover {
  color: var(--color-accent);
}

.post-description {
  margin: var(--space-sm) 0 0;
  color: var(--color-text-secondary);
}

/* Error page */
.error-page {
  text-align: center;
  padding: var(--space-xl) 0;
}

.error-page h1 {
  font-size: 4rem;
  color: var(--color-accent);
  margin-bottom: var(--space-sm);
}

/* ==========================================================================
   Page Styles (T032)
   ========================================================================== */

.page-header h1 {
  margin-top: 0;
}

.page-content {
  line-height: var(--line-height);
}

.page-content p {
  margin-bottom: var(--space-md);
}

/* ==========================================================================
   Tag Page Styles (T035)
   ========================================================================== */

.tag-header {
  margin-bottom: var(--space-xl);
  border-bottom: 1px solid var(--color-border);
  padding-bottom: var(--space-md);
}

.tag-header h1 {
  margin-top: 0;
  margin-bottom: var(--space-xs);
}

.tag-count {
  color: var(--color-text-secondary);
  margin: 0;
}

.back-link {
  margin-top: var(--space-xl);
  padding-top: var(--space-md);
  border-top: 1px solid var(--color-border);
}

/* ==========================================================================
   Explore Page Styles (T049)
   ========================================================================== */

.explore-header {
  margin-bottom: var(--space-lg);
}

.explore-header h1 {
  margin-top: 0;
  margin-bottom: var(--space-xs);
}

.explore-header p {
  color: var(--color-text-secondary);
  margin: 0;
}

.explore-container {
  display: grid;
  gap: var(--space-lg);
}

@media (min-width: 768px) {
  .explore-container {
    grid-template-columns: 2fr 1fr;
    align-items: start;
  }
}

/* Graph container */
.graph-container {
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: 4px;
  min-height: 300px;
  overflow: hidden;
}

.graph-container svg {
  display: block;
  width: 100%;
  touch-action: manipulation;
}

/* Network graph in explore page */
.explore-graph.network-graph {
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: 4px;
  margin: 0;
  min-height: 400px;
}

.explore-graph .graph-viewport {
  height: 400px; /* Fixed height for explore layout */
  background: var(--color-bg);
}

.explore-graph .graph-status {
  background: var(--color-bg);
  color: var(--color-text-secondary);
  border-top: 1px solid var(--color-border);
}

.explore-graph .graph-status .loading-message {
  color: var(--color-accent);
}

/* Network graph light theme overrides for explore page */
.explore-graph[data-theme="brand-dark"] {
  background: var(--color-bg);
}

.explore-graph .graph-viewport svg {
  background: var(--color-bg);
}

.explore-graph .graph-label {
  fill: var(--color-text);
}

.explore-graph .graph-label.tag {
  fill: var(--color-text);
  text-shadow: 1px 1px 2px rgba(255, 255, 255, 0.8);
}

.explore-graph .graph-label.post {
  fill: var(--color-text);
  text-shadow: 1px 1px 2px rgba(255, 255, 255, 0.8);
}

.explore-graph .graph-edge {
  stroke: var(--color-text-secondary);
  stroke-opacity: 0.4;
}

.explore-graph .graph-edge.active {
  stroke: var(--color-accent);
  stroke-opacity: 0.8;
}

/* List view */
.list-view {
  display: flex;
  flex-direction: column;
  gap: var(--space-md);
}

.content-search {
  position: relative;
  margin-bottom: 0;
  margin-top: 0;
}

.search-controls {
  display: flex;
  gap: var(--space-xs);
  align-items: stretch;
  flex-wrap: nowrap;
  margin-top: 0;
}

.content-search-input {
  flex: 1;
  min-width: 200px;
  padding: 0.5rem 0.75rem;
  border: 1px solid var(--color-border);
  border-radius: 4px;
  font-family: var(--font-family);
  font-size: 0.9rem;
  color: var(--color-text);
  background: var(--color-bg);
  transition: border-color 0.2s, box-shadow 0.2s;
}

.content-search-input:focus {
  outline: none;
  border-color: var(--color-accent);
  box-shadow: 0 0 0 2px rgba(210, 105, 30, 0.2);
}

.content-search-input::placeholder {
  color: var(--color-text-secondary);
}

.clear-search-btn {
  background: var(--color-border);
  border: none;
  padding: 0.5rem 1rem;
  border-radius: 4px;
  font-family: var(--font-family);
  font-size: 0.85rem;
  color: var(--color-text);
  cursor: pointer;
  transition: background-color 0.2s, color 0.2s;
  white-space: nowrap;
}

.clear-search-btn:hover {
  background: var(--color-accent);
  color: var(--color-bg);
}

.search-status {
  margin-top: var(--space-xs);
  padding: var(--space-xs);
  color: var(--color-text-secondary);
  font-size: 0.85rem;
  font-style: italic;
}

.search-results {
  position: absolute;
  top: 100%;
  left: 0;
  right: 0;
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: 4px;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
  z-index: 100;
  max-height: 200px;
  overflow-y: auto;
}

.search-result-tag {
  display: block;
  width: 100%;
  padding: 0.5rem 0.75rem;
  border: none;
  background: transparent;
  text-align: left;
  color: var(--color-text);
  cursor: pointer;
  font-family: var(--font-family);
  font-size: 0.85rem;
  transition: background-color 0.2s;
}

.search-result-tag:hover {
  background: var(--color-border);
}

.search-result-tag:focus {
  outline: none;
  background: var(--color-accent);
  color: var(--color-bg);
}

.search-no-results {
  padding: 0.75rem;
  color: var(--color-text-secondary);
  font-size: 0.85rem;
  text-align: center;
  font-style: italic;
}

/* Selected Tags Chips */
.selected-tags {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-xs);
  margin-top: var(--space-xs);
  padding-top: var(--space-xs);
  border-top: 1px solid var(--color-border);
}

.tag-chip {
  display: inline-flex;
  align-items: center;
  gap: 0.25rem;
  background: var(--color-accent);
  color: var(--color-bg);
  padding: 0.25rem 0.5rem;
  border-radius: 12px;
  font-size: 0.8rem;
  font-family: var(--font-family);
  max-width: 150px;
}

.tag-chip-remove {
  background: none;
  border: none;
  color: inherit;
  cursor: pointer;
  font-size: 1rem;
  font-weight: bold;
  line-height: 1;
  padding: 0;
  margin: 0 0 0 0.25rem;
  width: 16px;
  height: 16px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 50%;
  transition: background-color 0.2s;
}

.tag-chip-remove:hover {
  background: rgba(255, 255, 255, 0.2);
}

.tag-chip-remove:focus {
  outline: 1px solid currentColor;
  outline-offset: 1px;
}

/* Mobile responsiveness for search controls */
@media (max-width: 480px) {
  .search-controls {
    flex-wrap: wrap;
  }

  .content-search-input {
    min-width: 150px;
    flex: 1 1 auto;
  }

  .clear-search-btn {
    flex-shrink: 0;
  }
}

.post-list-compact {
  list-style: none;
  padding: 0;
  margin: 0;
  max-height: 16rem;
  overflow-y: auto;
}

.post-list-compact li {
  padding: var(--space-sm) 0;
  border-bottom: 1px solid var(--color-border);
  transition: background-color 0.2s;
}

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

.post-list-compact li.highlighted {
  background-color: rgba(183, 65, 14, 0.1);
  margin: 0 calc(-1 * var(--space-sm));
  padding-left: var(--space-sm);
  padding-right: var(--space-sm);
}

.post-list-compact li.search-match mark {
  background-color: rgba(210, 105, 30, 0.3);
  color: inherit;
  padding: 0 2px;
  border-radius: 2px;
}

.post-list-compact a {
  display: block;
  color: var(--color-text);
  font-weight: 500;
}

.post-list-compact a:hover {
  color: var(--color-accent);
}

.post-list-compact time {
  display: block;
  font-size: 0.85rem;
  color: var(--color-text-secondary);
  margin-top: var(--space-xs);
}

/* Visually hidden (accessibility) */
.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

/* ==========================================================================
   Title Animation System (replaces typewriter)
   ========================================================================== */

/* Shared letter styles */
.title-letter {
  display: inline-block;
  position: relative;
}

.title-char-normal {
  color: var(--color-text);
}

.title-char-accent {
  color: var(--color-accent);
}

/* Reduced motion: skip all title animations */
@media (prefers-reduced-motion: reduce) {
  .title-letter {
    animation: none !important;
    opacity: 1 !important;
    transform: none !important;
  }
}

/* ==========================================================================
   Subtle Background Textures (T027-T030)
   ========================================================================== */

/* Main content areas */
.post,
.page,
.post-preview {
  position: relative;
}

.post::before,
.page::before,
.post-preview::before {
  content: '';
  position: absolute;
  top: -1rem;
  left: -1rem;
  right: -1rem;
  bottom: -1rem;
  background:
    /* Subtle noise texture */
    radial-gradient(
      circle at 25% 25%,
      rgba(210, 105, 30, var(--texture-opacity)) 1px,
      transparent 1px
    ),
    /* Faint gradient */
    linear-gradient(
      135deg,
      rgba(210, 105, 30, var(--gradient-opacity)) 0%,
      transparent 30%
    );
  background-size: var(--texture-size) var(--texture-size), 100% 100%;
  border-radius: 4px;
  z-index: -1;
}

/* Site header enhancement */
.site-header {
  position: relative;
}

.site-header::after {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background:
    linear-gradient(
      to right,
      rgba(253, 251, 247, 0.8),
      rgba(210, 105, 30, var(--gradient-opacity)) 50%,
      rgba(253, 251, 247, 0.8)
    );
  z-index: -1;
}

/* Mobile optimization */
@media (max-width: 768px) {
  .post::before,
  .page::before,
  .post-preview::before {
    /* Reduce texture complexity on mobile */
    background:
      linear-gradient(
        135deg,
        rgba(210, 105, 30, calc(var(--gradient-opacity) * 0.5)) 0%,
        transparent 50%
      );
    background-size: 100% 100%;
  }
}

/* ==========================================================================
   Comments Section
   ========================================================================== */

.comments-section {
  max-width: var(--max-width);
  margin: var(--space-xl) auto;
  padding: 0 var(--space-sm);
}

.comments-heading {
  font-size: calc(var(--font-size-base) * var(--type-scale));
  margin-bottom: var(--space-md);
  color: var(--color-text);
  border-bottom: 1px solid var(--color-border);
  padding-bottom: var(--space-xs);
}

.giscus-container {
  min-height: 150px;
}