/* ============================================
   Personal Website - Main Stylesheet
   Obsidian-esque minimalist design
   ============================================ */

/* Google Fonts - Inter */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700&display=swap');

/* CSS Variables - Light Theme (Academic B&W) */
:root {
  /* Colors - Light Mode - Clean Academic */
  --bg-primary: #ffffff;
  --bg-secondary: #f8f8f8;
  --bg-sidebar: #fafafa;
  --text-primary: #111111;
  --text-secondary: #444444;
  --text-muted: #777777;
  --accent: #000000;
  --border: #dddddd;
  --hover: #f0f0f0;
  --icon-color: #555555;
  --link-color: #000000;

  /* Color scheme */
  color-scheme: light dark;
}

/* Dark Theme - Academic Dark */
[data-theme="dark"] {
  --bg-primary: #111111;
  --bg-secondary: #1a1a1a;
  --bg-sidebar: #141414;
  --text-primary: #eeeeee;
  --text-secondary: #aaaaaa;
  --text-muted: #777777;
  --accent: #ffffff;
  --border: #333333;
  --hover: #222222;
  --icon-color: #999999;
  --link-color: #ffffff;
}

/* System preference detection */
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg-primary: #111111;
    --bg-secondary: #1a1a1a;
    --bg-sidebar: #141414;
    --text-primary: #eeeeee;
    --text-secondary: #aaaaaa;
    --text-muted: #777777;
    --accent: #ffffff;
    --border: #333333;
    --hover: #222222;
    --icon-color: #999999;
    --link-color: #ffffff;
  }
}

/* Typography (shared) */
:root {
  /* Typography */
  --font-family-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-family-serif: 'Times New Roman', Times, Georgia, serif;
  --font-family: var(--font-family-serif);
  --font-size-base: 16px;
  --font-size-sm: 13px;
  --font-size-xs: 12px;
  --font-size-lg: 16px;
  --font-size-xl: 20px;
  --font-size-2xl: 24px;
  --font-size-3xl: 32px;
  --line-height: 1.45;

  /* Layout */
  --sidebar-width: 220px;
  --content-max-width: 680px;
  --spacing-xs: 4px;
  --spacing-sm: 8px;
  --spacing-md: 16px;
  --spacing-lg: 24px;
  --spacing-xl: 32px;
  --spacing-2xl: 48px;

  /* Transitions */
  --transition-fast: 150ms ease;
  --transition-normal: 250ms ease;
}

/* Reset & Base */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-size: var(--font-size-base);
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-family);
  background-color: var(--bg-primary);
  color: var(--text-primary);
  line-height: var(--line-height);
  min-height: 100vh;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

a {
  color: var(--link-color, var(--accent));
  text-decoration: none;
  transition: color var(--transition-fast);
}

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

/* Layout Container */
.layout {
  display: flex;
  min-height: 100vh;
}

/* ============================================
   Sidebar
   ============================================ */
.sidebar {
  position: fixed;
  left: 0;
  top: 0;
  width: var(--sidebar-width);
  height: 100vh;
  background-color: var(--bg-sidebar);
  border-right: 1px solid var(--border);
  display: flex;
  flex-direction: column;
  z-index: 100;
  transition: transform var(--transition-normal);
  font-family: var(--font-family-sans);
}

.sidebar-header {
  padding: var(--spacing-lg);
  border-bottom: 1px solid var(--border);
}

.sidebar-logo {
  font-family: var(--font-family-serif);
  font-size: var(--font-size-lg);
  font-weight: 400;
  font-style: italic;
  color: var(--accent);
  letter-spacing: 0.02em;
}

.sidebar-logo:hover {
  text-decoration: none;
}

.sidebar-nav {
  flex: 1;
  padding: var(--spacing-md) 0;
  overflow-y: auto;
}

.nav-item {
  display: block;
  padding: var(--spacing-sm) var(--spacing-lg);
  color: var(--text-secondary);
  font-size: var(--font-size-sm);
  transition: all var(--transition-fast);
}

.nav-item:hover {
  color: var(--text-primary);
  background-color: var(--hover);
}

.nav-item.active {
  color: var(--accent);
  background-color: var(--hover);
}

/* Nav Section (always expanded, Obsidian-style) */
.nav-section {
  margin: var(--spacing-xs) 0;
}

.nav-section-header {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  padding: var(--spacing-sm) var(--spacing-lg);
  color: var(--text-secondary);
  font-size: var(--font-size-sm);
  transition: all var(--transition-fast);
}

.nav-section-header:hover {
  color: var(--text-primary);
  background-color: var(--hover);
}

.nav-section-content {
  display: block;
}

/* Folder Icon */
.folder-icon {
  width: 16px;
  height: 16px;
  color: var(--icon-color);
  flex-shrink: 0;
}

/* File Icon */
.file-icon {
  width: 14px;
  height: 14px;
  color: var(--icon-color);
  flex-shrink: 0;
}

.nav-subitem {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  padding: var(--spacing-xs) var(--spacing-lg);
  padding-left: calc(var(--spacing-lg) + var(--spacing-md));
  color: var(--text-muted);
  font-size: var(--font-size-xs);
  transition: all var(--transition-fast);
}

.nav-subitem:hover {
  color: var(--text-primary);
  background-color: var(--hover);
}

.nav-subitem.active {
  color: var(--accent);
}

/* Nav item with icon */
.nav-item {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
}

/* Theme Toggle */
.theme-toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 32px;
  margin: var(--spacing-md) var(--spacing-lg);
  background: transparent;
  border: 1px solid var(--border);
  border-radius: 4px;
  color: var(--text-secondary);
  cursor: pointer;
  transition: all var(--transition-fast);
}

.theme-toggle:hover {
  color: var(--text-primary);
  border-color: var(--text-secondary);
}

.theme-toggle svg {
  width: 16px;
  height: 16px;
}

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

.theme-toggle .moon-icon {
  display: block;
}

[data-theme="dark"] .theme-toggle .sun-icon,
:root:not([data-theme="light"]) .theme-toggle .sun-icon {
  display: block;
}

[data-theme="dark"] .theme-toggle .moon-icon,
:root:not([data-theme="light"]) .theme-toggle .moon-icon {
  display: none;
}

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

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

/* Write Button (localhost only) */
.write-btn {
  margin: var(--spacing-md) var(--spacing-lg);
  padding: var(--spacing-sm) var(--spacing-md);
  background-color: var(--accent);
  color: var(--bg-primary);
  border: none;
  border-radius: 4px;
  font-size: var(--font-size-sm);
  font-weight: 500;
  cursor: pointer;
  text-align: center;
  transition: opacity var(--transition-fast);
  display: none;
}

.write-btn:hover {
  opacity: 0.9;
}

body.localhost .write-btn {
  display: block;
}

/* Sidebar Footer */
.sidebar-footer {
  padding: var(--spacing-md) var(--spacing-lg);
  border-top: 1px solid var(--border);
  font-size: var(--font-size-xs);
  color: var(--text-muted);
}

/* ============================================
   Main Content
   ============================================ */
.main-content {
  flex: 1;
  margin-left: var(--sidebar-width);
  min-height: 100vh;
}

.content-wrapper {
  max-width: var(--content-max-width);
  margin: 0 auto;
  padding: var(--spacing-2xl) var(--spacing-lg);
}

/* Page Header */
.page-header {
  margin-bottom: var(--spacing-2xl);
  padding-bottom: var(--spacing-lg);
  border-bottom: 1px solid var(--border);
}

.page-title {
  font-family: var(--font-family-serif);
  font-size: var(--font-size-3xl);
  font-weight: 400;
  font-style: italic;
  color: var(--accent);
  letter-spacing: 0.01em;
  margin-bottom: var(--spacing-sm);
}

.page-description {
  color: var(--text-secondary);
  font-size: var(--font-size-base);
  font-style: italic;
}

/* Home Page */
.home-title {
  font-family: var(--font-family-serif);
  font-size: var(--font-size-2xl);
  font-weight: 400;
  font-style: italic;
  color: var(--text-primary);
  margin-bottom: var(--spacing-xl);
}

.home-star {
  font-style: normal;
  font-size: var(--font-size-sm);
  vertical-align: super;
  margin-left: 2px;
}

.home-intro {
  font-family: var(--font-family-serif);
  font-size: var(--font-size-sm);
  color: var(--text-secondary);
  margin-bottom: var(--spacing-xl);
}

.home-hero {
  display: flex;
  align-items: flex-start;
  gap: var(--spacing-xl);
}

.home-image {
  flex-shrink: 0;
  margin: 0;
}

.home-image img {
  display: block;
  max-width: 320px;
  height: auto;
}

.home-image figcaption {
  font-family: var(--font-family-sans);
  font-size: var(--font-size-xs);
  color: var(--text-muted);
  margin-top: var(--spacing-sm);
  font-style: italic;
}

.home-quote {
  border: none;
  padding: 0;
  margin: 0;
  padding-top: var(--spacing-md);
}

.home-quote p {
  font-family: var(--font-family-serif);
  font-size: var(--font-size-base);
  font-style: italic;
  line-height: 1.5;
  color: var(--text-primary);
  margin-bottom: var(--spacing-sm);
}

.home-quote cite {
  display: block;
  font-family: var(--font-family-sans);
  font-size: var(--font-size-xs);
  font-style: normal;
  color: var(--text-muted);
}

.home-footnote {
  margin-top: var(--spacing-2xl);
  font-family: var(--font-family-sans);
  font-size: var(--font-size-xs);
  color: var(--text-muted);
}

.home-footnote span {
  margin-right: 4px;
}

/* Breadcrumb */
.breadcrumb {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  margin-bottom: var(--spacing-lg);
  font-size: var(--font-size-sm);
  color: var(--text-muted);
}

.breadcrumb a {
  color: var(--text-secondary);
}

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

.breadcrumb-separator {
  color: var(--text-muted);
}

/* ============================================
   Writings List
   ============================================ */
.writings-list {
  list-style: none;
}

.writing-item {
  padding: var(--spacing-lg) 0;
  border-bottom: 1px solid var(--border);
}

.writing-item:last-child {
  border-bottom: none;
}

.writing-item-link {
  display: block;
}

.writing-item-title {
  font-size: var(--font-size-lg);
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: var(--spacing-xs);
  transition: color var(--transition-fast);
}

.writing-item-link:hover .writing-item-title {
  color: var(--accent);
}

.writing-item-meta {
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
  font-size: var(--font-size-xs);
  color: var(--text-muted);
  margin-bottom: var(--spacing-sm);
}

.writing-item-excerpt {
  color: var(--text-secondary);
  font-size: var(--font-size-sm);
  line-height: 1.5;
}

/* Category Tag */
.category-tag {
  display: inline-block;
  padding: 1px 6px;
  background-color: transparent;
  border: 1px solid var(--text-secondary);
  border-radius: 0;
  font-family: var(--font-family-sans);
  font-size: var(--font-size-xs);
  color: var(--text-secondary);
  text-transform: lowercase;
  letter-spacing: 0.03em;
}

/* ============================================
   Article Page
   ============================================ */
.article-header {
  margin-bottom: var(--spacing-xl);
}

.article-title {
  font-family: var(--font-family-serif);
  font-size: var(--font-size-2xl);
  font-weight: 400;
  font-style: italic;
  color: var(--accent);
  letter-spacing: 0.01em;
  margin-bottom: var(--spacing-md);
}

.article-meta {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: var(--spacing-md);
  font-size: var(--font-size-sm);
  color: var(--text-muted);
}

.article-content {
  margin-bottom: var(--spacing-2xl);
}

/* Article Navigation */
.article-nav {
  display: flex;
  justify-content: space-between;
  padding-top: var(--spacing-xl);
  border-top: 1px solid var(--border);
}

.article-nav-link {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-xs);
  max-width: 45%;
}

.article-nav-label {
  font-size: var(--font-size-xs);
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.article-nav-title {
  font-size: var(--font-size-sm);
  color: var(--text-secondary);
}

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

/* Table of Contents */
.toc {
  background-color: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: var(--spacing-md);
  margin-bottom: var(--spacing-xl);
}

.toc-title {
  font-size: var(--font-size-sm);
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: var(--spacing-sm);
}

.toc-list {
  list-style: none;
}

.toc-item {
  padding: var(--spacing-xs) 0;
}

.toc-link {
  font-size: var(--font-size-sm);
  color: var(--text-secondary);
}

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

.toc-item.level-2 {
  padding-left: var(--spacing-md);
}

.toc-item.level-3 {
  padding-left: var(--spacing-xl);
}

/* ============================================
   Search
   ============================================ */
.search-container {
  margin-bottom: var(--spacing-xl);
}

.search-input {
  width: 100%;
  padding: var(--spacing-sm) var(--spacing-md);
  background-color: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: 4px;
  color: var(--text-primary);
  font-family: var(--font-family-sans);
  font-size: var(--font-size-sm);
  outline: none;
  transition: border-color var(--transition-fast);
}

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

.search-input:focus {
  border-color: var(--text-secondary);
}

/* ============================================
   Contact Page
   ============================================ */
.contact-links {
  list-style: none;
}

.contact-item {
  padding: var(--spacing-md) 0;
  border-bottom: 1px solid var(--border);
}

.contact-item:last-child {
  border-bottom: none;
}

.contact-link {
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
  color: var(--text-secondary);
}

.contact-link:hover {
  color: var(--accent);
}

.contact-icon {
  width: 20px;
  height: 20px;
  opacity: 0.7;
}

/* ============================================
   Photos Page
   ============================================ */
.photo-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: var(--spacing-md);
}

.photo-item {
  aspect-ratio: 1;
  background-color: var(--bg-secondary);
  border-radius: 4px;
  overflow: hidden;
}

.photo-item img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: opacity var(--transition-normal);
}

.photo-item:hover img {
  opacity: 0.8;
}

/* ============================================
   Mobile Menu Toggle
   ============================================ */
.menu-toggle {
  display: none;
  position: fixed;
  top: var(--spacing-md);
  left: var(--spacing-md);
  z-index: 200;
  width: 40px;
  height: 40px;
  background-color: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: 4px;
  cursor: pointer;
  align-items: center;
  justify-content: center;
}

.menu-toggle svg {
  width: 20px;
  height: 20px;
  color: var(--text-primary);
}

/* Mobile Overlay */
.sidebar-overlay {
  display: none;
  position: fixed;
  inset: 0;
  background-color: rgba(0, 0, 0, 0.5);
  z-index: 99;
}

/* ============================================
   Responsive Design
   ============================================ */
@media (max-width: 768px) {
  .menu-toggle {
    display: flex;
  }

  .sidebar {
    transform: translateX(-100%);
  }

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

  .sidebar-overlay.open {
    display: block;
  }

  .main-content {
    margin-left: 0;
  }

  .content-wrapper {
    padding-top: calc(var(--spacing-2xl) + 40px);
  }

  .page-title {
    font-size: var(--font-size-2xl);
  }

  .article-title {
    font-size: var(--font-size-xl);
  }

  .home-hero {
    flex-direction: column;
  }

  .home-image img {
    max-width: 100%;
  }
}

/* ============================================
   Utility Classes
   ============================================ */
.text-muted {
  color: var(--text-muted);
}

.text-secondary {
  color: var(--text-secondary);
}

.mt-sm { margin-top: var(--spacing-sm); }
.mt-md { margin-top: var(--spacing-md); }
.mt-lg { margin-top: var(--spacing-lg); }
.mt-xl { margin-top: var(--spacing-xl); }

.mb-sm { margin-bottom: var(--spacing-sm); }
.mb-md { margin-bottom: var(--spacing-md); }
.mb-lg { margin-bottom: var(--spacing-lg); }
.mb-xl { margin-bottom: var(--spacing-xl); }

.hidden {
  display: none !important;
}