/* ============================================
   CSS Variables & Theme - Minimal Style
   ============================================ */

:root {
  /* Light theme colors - Minimal inspired */
  --bg-primary: #ffffff;
  --bg-secondary: #f8f8f8;
  --bg-tertiary: #f0f0f0;
  --text-primary: #2e2e2e;
  --text-secondary: #666666;
  --text-tertiary: #999999;
  --border-color: #e5e5e5;
  --accent: #6366f1;
  --accent-hover: #4f46e5;

  /* Sidebar specific */
  --sidebar-bg: #1e1e1e;
  --sidebar-text: #d1d1d1;
  --sidebar-text-active: #ffffff;
  --sidebar-border: #2a2a2a;

  /* TOC sidebar */
  --toc-bg: #fafafa;
  --toc-border: #e5e5e5;

  /* Typography */
  --font-serif: 'EB Garamond', Georgia, serif;
  --font-mono: 'JetBrains Mono', 'Courier New', monospace;
  --font-ui: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;

  /* Spacing */
  --sidebar-width: 260px;
  --toc-width: 240px;
  --content-max-width: 750px;
  --spacing-xs: 0.25rem;
  --spacing-sm: 0.5rem;
  --spacing-md: 1rem;
  --spacing-lg: 1.5rem;
  --spacing-xl: 2rem;
  --spacing-2xl: 3rem;

  /* Animation */
  --transition-speed: 0.15s;
}

[data-theme="dark"] {
  --bg-primary: #1e1e1e;
  --bg-secondary: #252525;
  --bg-tertiary: #2a2a2a;
  --text-primary: #d1d1d1;
  --text-secondary: #999999;
  --text-tertiary: #666666;
  --border-color: #333333;
  --accent: #818cf8;
  --accent-hover: #a5b4fc;

  /* Sidebar stays dark */
  --sidebar-bg: #161616;
  --sidebar-text: #999999;
  --sidebar-text-active: #d1d1d1;
  --sidebar-border: #262626;

  /* TOC sidebar */
  --toc-bg: #252525;
  --toc-border: #333333;
}

/* ============================================
   Reset & Base Styles
   ============================================ */

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

html {
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: var(--font-serif);
  line-height: 1.6;
  color: var(--text-primary);
  background: var(--bg-primary);
  transition: background var(--transition-speed), color var(--transition-speed);
}

::selection {
  background: rgba(99, 102, 241, 0.2);
}

/* ============================================
   Typography
   ============================================ */

h1, h2, h3, h4, h5, h6 {
  line-height: 1.3;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: var(--spacing-md);
  margin-top: var(--spacing-xl);
}

h1:first-child,
h2:first-child,
h3:first-child {
  margin-top: 0;
}

h1 { font-size: 2rem; }
h2 { font-size: 1.6rem; }
h3 { font-size: 1.3rem; }
h4 { font-size: 1.1rem; }

p {
  margin-bottom: var(--spacing-md);
}

a {
  color: var(--accent);
  text-decoration: none;
  transition: color var(--transition-speed);
}

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

code, pre {
  font-family: var(--font-mono);
  font-size: 0.9rem;
}

code {
  background: var(--bg-secondary);
  padding: 0.15em 0.4em;
  border-radius: 3px;
  border: 1px solid var(--border-color);
}

pre {
  background: var(--bg-secondary);
  padding: var(--spacing-md);
  border-radius: 6px;
  overflow-x: auto;
  margin: var(--spacing-lg) 0;
  border: 1px solid var(--border-color);
}

pre code {
  background: none;
  padding: 0;
  border: none;
}

blockquote {
  border-left: 3px solid var(--accent);
  padding-left: var(--spacing-md);
  margin: var(--spacing-lg) 0;
  color: var(--text-secondary);
  font-style: italic;
}

hr {
  border: none;
  border-top: 1px solid var(--border-color);
  margin: var(--spacing-xl) 0;
}

ul, ol {
  margin-left: var(--spacing-lg);
  margin-bottom: var(--spacing-md);
}

li {
  margin-bottom: var(--spacing-sm);
}

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

.layout-container {
  display: grid;
  grid-template-columns: var(--sidebar-width) 1fr var(--toc-width);
  min-height: 100vh;
}

/* ============================================
   Left Sidebar Navigation
   ============================================ */

.sidebar {
  position: fixed;
  top: 0;
  left: 0;
  width: var(--sidebar-width);
  height: 100vh;
  background: var(--sidebar-bg);
  border-right: 1px solid var(--sidebar-border);
  overflow-y: auto;
  z-index: 100;
}

.sidebar-content {
  padding: var(--spacing-lg);
}

.sidebar-header {
  margin-bottom: var(--spacing-lg);
}

.sidebar .site-title {
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--sidebar-text-active);
  font-family: var(--font-ui);
  display: block;
}

.sidebar .site-title:hover {
  color: var(--sidebar-text-active);
  opacity: 0.9;
}

/* Theme Toggle in Sidebar */
.sidebar .theme-toggle {
  width: 100%;
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid var(--sidebar-border);
  border-radius: 6px;
  padding: var(--spacing-sm);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--sidebar-text);
  transition: all var(--transition-speed);
  margin-bottom: var(--spacing-lg);
}

.sidebar .theme-toggle:hover {
  background: rgba(255, 255, 255, 0.08);
  border-color: var(--sidebar-text);
}

.theme-toggle .theme-icon {
  width: 18px;
  height: 18px;
}

.theme-toggle .sun-icon { display: none; }
.theme-toggle .moon-icon { display: block; }

[data-theme="dark"] .theme-toggle .sun-icon { display: block; }
[data-theme="dark"] .theme-toggle .moon-icon { display: none; }

/* Sidebar Navigation */
.sidebar-nav {
  font-family: var(--font-ui);
}

.nav-list {
  list-style: none;
  margin: 0;
  padding: 0;
}

.nav-item {
  margin-bottom: var(--spacing-xs);
}

.nav-link {
  display: block;
  padding: var(--spacing-sm) var(--spacing-md);
  color: var(--sidebar-text);
  border-radius: 6px;
  transition: all var(--transition-speed);
  font-size: 0.95rem;
}

.nav-link:hover {
  background: rgba(255, 255, 255, 0.05);
  color: var(--sidebar-text-active);
}

.nav-link.active {
  background: rgba(255, 255, 255, 0.08);
  color: var(--sidebar-text-active);
  font-weight: 500;
}

/* ============================================
   Main Content Area
   ============================================ */

.main-content {
  grid-column: 2;
  padding: var(--spacing-2xl) var(--spacing-xl);
  max-width: var(--content-max-width);
  margin: 0 auto;
  width: 100%;
}

/* ============================================
   Right Sidebar TOC
   ============================================ */

.toc-sidebar {
  position: fixed;
  top: 0;
  right: 0;
  width: var(--toc-width);
  height: 100vh;
  background: var(--toc-bg);
  border-left: 1px solid var(--toc-border);
  overflow-y: auto;
  padding: var(--spacing-2xl) var(--spacing-lg);
}

.toc-title {
  font-size: 0.85rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-tertiary);
  margin-bottom: var(--spacing-md);
  font-family: var(--font-ui);
}

.toc-nav {
  font-size: 0.9rem;
  font-family: var(--font-ui);
}

.toc-nav ul {
  list-style: none;
  margin: 0;
  padding: 0;
}

.toc-nav li {
  margin-bottom: var(--spacing-sm);
}

.toc-nav a {
  color: var(--text-secondary);
  display: block;
  padding: var(--spacing-xs) 0;
  transition: color var(--transition-speed);
}

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

.toc-nav ul ul {
  margin-left: var(--spacing-md);
  margin-top: var(--spacing-xs);
}

/* ============================================
   Homepage Specific
   ============================================ */

.hero {
  margin-bottom: var(--spacing-2xl);
  padding-bottom: var(--spacing-xl);
  border-bottom: 1px solid var(--border-color);
}

.hero-title {
  font-size: 2.5rem;
  margin-bottom: var(--spacing-md);
  font-weight: 700;
}

.hero-description {
  font-size: 1.15rem;
  color: var(--text-secondary);
  line-height: 1.6;
}

.section-header {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  margin-bottom: var(--spacing-lg);
  padding-bottom: var(--spacing-sm);
  border-bottom: 1px solid var(--border-color);
}

.section-header h2 {
  margin: 0;
  font-size: 1.5rem;
}

.view-all {
  font-size: 0.9rem;
  color: var(--text-tertiary);
  font-family: var(--font-ui);
}

.view-all:hover {
  color: var(--accent);
}

.posts-section,
.projects-section {
  margin-bottom: var(--spacing-2xl);
}

/* ============================================
   Post Cards
   ============================================ */

.post-list {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-lg);
}

.post-card {
  padding-bottom: var(--spacing-lg);
  border-bottom: 1px solid var(--border-color);
}

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

.post-meta {
  font-size: 0.85rem;
  color: var(--text-tertiary);
  margin-bottom: var(--spacing-sm);
  font-family: var(--font-ui);
}

.post-title {
  margin-bottom: var(--spacing-sm);
  margin-top: 0;
  font-size: 1.3rem;
}

.post-title a {
  color: var(--text-primary);
}

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

.post-summary {
  color: var(--text-secondary);
  margin-bottom: 0;
  line-height: 1.6;
}

.separator {
  margin: 0 var(--spacing-sm);
  color: var(--text-tertiary);
}

/* ============================================
   Project Cards
   ============================================ */

.project-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: var(--spacing-md);
}

.project-card {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  padding: var(--spacing-lg);
  transition: all var(--transition-speed);
}

.project-card:hover {
  border-color: var(--accent);
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
}

.project-title {
  font-size: 1.15rem;
  margin-bottom: var(--spacing-sm);
  margin-top: 0;
}

.project-title a {
  color: var(--text-primary);
}

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

.project-description {
  color: var(--text-secondary);
  font-size: 0.95rem;
  margin-bottom: var(--spacing-md);
  line-height: 1.5;
}

.project-tech {
  display: flex;
  flex-wrap: wrap;
  gap: var(--spacing-sm);
}

.tech-tag {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  background: var(--bg-tertiary);
  color: var(--text-secondary);
  padding: 0.25rem 0.5rem;
  border-radius: 4px;
  border: 1px solid var(--border-color);
}

/* ============================================
   Single Pages
   ============================================ */

.page-header,
.post-header,
.project-header {
  margin-bottom: var(--spacing-xl);
  padding-bottom: var(--spacing-md);
  border-bottom: 1px solid var(--border-color);
}

.page-title,
.post-title,
.project-title {
  font-size: 2.5rem;
  margin-bottom: var(--spacing-md);
  font-weight: 700;
}

.post-header .post-meta {
  margin-top: var(--spacing-sm);
}

.page-content,
.post-content,
.project-content {
  font-size: 1.05rem;
  line-height: 1.7;
}

.page-content img,
.post-content img,
.project-content img {
  max-width: 100%;
  height: auto;
  border-radius: 6px;
  margin: var(--spacing-lg) 0;
  border: 1px solid var(--border-color);
}

/* Project Meta */
.project-meta {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-md);
  margin-top: var(--spacing-md);
}

.project-links {
  display: flex;
  gap: var(--spacing-md);
  flex-wrap: wrap;
}

.project-link {
  font-family: var(--font-ui);
  font-size: 0.9rem;
  color: var(--accent);
  border: 1px solid var(--accent);
  padding: 0.4rem 0.8rem;
  border-radius: 6px;
  transition: all var(--transition-speed);
}

.project-link:hover {
  background: var(--accent);
  color: white;
}

/* ============================================
   Navigation (Post/Project)
   ============================================ */

.post-navigation,
.project-navigation {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--spacing-md);
  margin-top: var(--spacing-2xl);
  padding-top: var(--spacing-xl);
  border-top: 1px solid var(--border-color);
}

.nav-prev,
.nav-next {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-xs);
  padding: var(--spacing-md);
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: 6px;
  transition: all var(--transition-speed);
  color: var(--text-primary);
}

.nav-prev:hover,
.nav-next:hover {
  border-color: var(--accent);
  transform: translateY(-2px);
}

.nav-next {
  text-align: right;
}

.nav-label {
  font-size: 0.85rem;
  font-family: var(--font-ui);
  color: var(--text-tertiary);
}

.nav-title {
  font-weight: 500;
  color: var(--text-primary);
}

/* ============================================
   Section Pages
   ============================================ */

.section-page-header {
  margin-bottom: var(--spacing-2xl);
  padding-bottom: var(--spacing-lg);
  border-bottom: 1px solid var(--border-color);
}

.section-page-header h1 {
  margin-bottom: var(--spacing-md);
}

.section-description {
  color: var(--text-secondary);
  font-size: 1.05rem;
}

/* ============================================
   Pagination
   ============================================ */

.pagination {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-top: var(--spacing-2xl);
  padding-top: var(--spacing-lg);
  border-top: 1px solid var(--border-color);
  font-family: var(--font-ui);
}

.pagination-info {
  font-size: 0.9rem;
  color: var(--text-secondary);
}

.pagination-prev,
.pagination-next {
  font-size: 0.9rem;
  padding: 0.5rem 1rem;
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: 6px;
  transition: all var(--transition-speed);
}

.pagination-prev:hover,
.pagination-next:hover {
  border-color: var(--accent);
  color: var(--accent);
}

/* ============================================
   Utilities
   ============================================ */

.no-content {
  text-align: center;
  color: var(--text-secondary);
  padding: var(--spacing-2xl) 0;
}

.fade-in {
  animation: fadeIn 0.4s ease-in;
}

@keyframes fadeIn {
  from {
    opacity: 0;
    transform: translateY(10px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* ============================================
   Responsive Design
   ============================================ */

@media (max-width: 1200px) {
  /* Hide TOC on medium screens */
  .layout-container {
    grid-template-columns: var(--sidebar-width) 1fr;
  }

  .toc-sidebar {
    display: none;
  }
}

@media (max-width: 768px) {
  /* Mobile: Hide sidebar by default, stack content */
  :root {
    --sidebar-width: 0px;
  }

  .layout-container {
    grid-template-columns: 1fr;
  }

  .sidebar {
    transform: translateX(-100%);
    transition: transform 0.3s ease;
  }

  .sidebar.open {
    transform: translateX(0);
  }

  .main-content {
    grid-column: 1;
    padding: var(--spacing-lg);
  }

  .hero-title {
    font-size: 2rem;
  }

  .project-grid {
    grid-template-columns: 1fr;
  }

  .post-navigation,
  .project-navigation {
    grid-template-columns: 1fr;
  }

  .nav-next {
    text-align: left;
  }
}

/* Smooth scrolling */
html {
  scroll-behavior: smooth;
}

/* Custom scrollbar for sidebars */
.sidebar::-webkit-scrollbar,
.toc-sidebar::-webkit-scrollbar {
  width: 6px;
}

.sidebar::-webkit-scrollbar-track,
.toc-sidebar::-webkit-scrollbar-track {
  background: transparent;
}

.sidebar::-webkit-scrollbar-thumb {
  background: rgba(255, 255, 255, 0.1);
  border-radius: 3px;
}

.toc-sidebar::-webkit-scrollbar-thumb {
  background: var(--border-color);
  border-radius: 3px;
}

.sidebar::-webkit-scrollbar-thumb:hover,
.toc-sidebar::-webkit-scrollbar-thumb:hover {
  background: rgba(255, 255, 255, 0.2);
}