/* ==========================================================================
   Minimal CSS Reset
   ========================================================================== */

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

* {
  margin: 0;
}

body {
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

img, picture, video, canvas, svg {
  display: block;
  max-width: 100%;
  height: auto;
}

input, button, textarea, select {
  font: inherit;
}

p, h1, h2, h3, h4, h5, h6 {
  overflow-wrap: break-word;
}

/* ==========================================================================
   Design Tokens
   ========================================================================== */

:root {
  /* Colors - Light Mode */
  --color-text: #1a1a1a;
  --color-background: #ffffff;
  --color-accent: #666666;
  --color-link: #0066cc;
  --color-link-hover: #004499;
  --color-code-bg: #f5f5f5;
  --color-code-text: #d01040;
  --color-border: #e0e0e0;

  /* Typography */
  --font-serif: Georgia, 'Iowan Old Style', 'Palatino Linotype', serif;
  --font-sans: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Helvetica Neue', Arial, sans-serif;
  --font-mono: 'SF Mono', Monaco, 'Cascadia Code', 'Courier New', monospace;

  --font-size-body: clamp(18px, 2.5vw, 21px);
  --font-size-h1: clamp(2rem, 5vw, 3rem);
  --font-size-h2: clamp(1.5rem, 4vw, 2.25rem);
  --font-size-h3: clamp(1.25rem, 3vw, 1.75rem);
  --font-size-h4: clamp(1.1rem, 2.5vw, 1.35rem);
  --font-size-small: 0.9em;

  --line-height-body: 1.7;
  --line-height-heading: 1.2;

  /* Spacing */
  --space-xs: 0.25rem;
  --space-sm: 0.5rem;
  --space-md: 1rem;
  --space-lg: 2rem;
  --space-xl: 4rem;
  --space-2xl: 6rem;

  /* Layout */
  --content-max-width: 680px;
  --transition-speed: 0.3s;
  --border-radius: 4px;

  /* Sidebar */
  --sidebar-width: 280px;
  --sidebar-gap: 4rem;
  --sidebar-padding: var(--space-lg);
  --sidebar-border: 1px solid var(--color-border);
}

/* Dark Mode - System Preference */
@media (prefers-color-scheme: dark) {
  :root {
    --color-text: #e4e4e4;
    --color-background: #1a1a1a;
    --color-accent: #a0a0a0;
    --color-link: #6699ff;
    --color-link-hover: #99ccff;
    --color-code-bg: #2a2a2a;
    --color-code-text: #ff6b9d;
    --color-border: #3a3a3a;
  }
}

/* Dark Mode - Manual Toggle */
[data-theme="dark"] {
  --color-text: #e4e4e4;
  --color-background: #1a1a1a;
  --color-accent: #a0a0a0;
  --color-link: #6699ff;
  --color-link-hover: #99ccff;
  --color-code-bg: #2a2a2a;
  --color-code-text: #ff6b9d;
  --color-border: #3a3a3a;
}

/* ==========================================================================
   Base Styles
   ========================================================================== */

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

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

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-sans);
  line-height: var(--line-height-heading);
  font-weight: 700;
}

h1 {
  font-size: var(--font-size-h1);
  margin: 0 0 var(--space-lg);
}

h2 {
  font-size: var(--font-size-h2);
  margin: var(--space-2xl) 0 var(--space-md);
}

h3 {
  font-size: var(--font-size-h3);
  margin: var(--space-xl) 0 var(--space-md);
}

h4 {
  font-size: var(--font-size-h4);
  margin: var(--space-lg) 0 var(--space-sm);
}

p {
  margin-bottom: var(--space-lg);
}

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

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

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

/* Lists */
ul, ol {
  margin-bottom: var(--space-lg);
  padding-left: var(--space-lg);
}

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

/* Blockquotes */
blockquote {
  margin: var(--space-xl) 0;
  padding-left: var(--space-lg);
  border-left: 4px solid var(--color-accent);
  font-style: italic;
  color: var(--color-accent);
}

/* Code */
code {
  font-family: var(--font-mono);
  font-size: 0.9em;
  background-color: var(--color-code-bg);
  color: var(--color-code-text);
  padding: 0.2em 0.4em;
  border-radius: var(--border-radius);
}

pre {
  margin: var(--space-xl) 0;
  padding: var(--space-lg);
  background-color: var(--color-code-bg);
  border-radius: var(--border-radius);
  overflow-x: auto;
}

pre code {
  padding: 0;
  background: none;
  color: var(--color-text);
}

/* Horizontal Rule */
hr {
  margin: var(--space-2xl) 0;
  border: none;
  border-top: 1px solid var(--color-border);
}

/* Images & Figures */
figure {
  margin: var(--space-xl) 0;
}

figcaption {
  margin-top: var(--space-sm);
  font-size: var(--font-size-small);
  color: var(--color-accent);
  font-style: italic;
  text-align: center;
}

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

.site-header, .site-footer {
  font-family: var(--font-sans);
}

.site-header {
  padding: var(--space-lg) 0;
  border-bottom: 1px solid var(--color-border);
}

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

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

.site-title:hover {
  text-decoration: none;
}

.theme-toggle {
  background: none;
  border: 1px solid var(--color-border);
  padding: var(--space-sm) var(--space-md);
  border-radius: var(--border-radius);
  cursor: pointer;
  color: var(--color-text);
  transition: border-color var(--transition-speed);
}

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

.theme-toggle:focus {
  outline: 2px solid var(--color-link);
  outline-offset: 2px;
}

main {
  max-width: var(--content-max-width);
  margin: 0 auto;
  padding: var(--space-2xl) var(--space-md);
}

/* Remove padding when main contains post-wrapper (sidebar layout) */
main:has(.post-wrapper) {
  max-width: none;
  padding: 0;
}

.site-footer {
  padding: var(--space-xl) 0;
  border-top: 1px solid var(--color-border);
  font-size: var(--font-size-small);
  color: var(--color-accent);
}

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

/* ==========================================================================
   Post Layout with Sidebar
   ========================================================================== */

.post-wrapper {
  display: block;
  max-width: var(--content-max-width);
  margin: 0 auto;
  padding: var(--space-2xl) var(--space-md);
  overflow-x: hidden;
}

@media (min-width: 1024px) {
  .post-wrapper {
    display: grid;
    grid-template-columns: var(--content-max-width) var(--sidebar-width);
    gap: var(--sidebar-gap);
    max-width: calc(var(--content-max-width) + var(--sidebar-gap) + var(--sidebar-width));
    padding: var(--space-2xl) var(--space-lg);
  }
}

/* ==========================================================================
   Post Styles
   ========================================================================== */

.post-header {
  margin-bottom: var(--space-2xl);
}

.post-title {
  margin-bottom: var(--space-md);
}

.post-meta {
  font-family: var(--font-sans);
  font-size: var(--font-size-small);
  color: var(--color-accent);
  display: flex;
  gap: var(--space-md);
}

.post-content {
  /* Content inherits base typography styles */
}

/* ==========================================================================
   Sidebar Styles
   ========================================================================== */

.sidebar {
  margin-top: var(--space-xl);
  padding-top: var(--space-lg);
  border-top: var(--sidebar-border);
  font-family: var(--font-sans);
}

.sidebar-title {
  font-size: 1rem;
  font-weight: 600;
  margin-bottom: var(--space-md);
  color: var(--color-text);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

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

.sidebar-list li {
  margin-bottom: var(--space-md);
  padding-bottom: var(--space-md);
  border-bottom: 1px solid var(--color-border);
}

.sidebar-list li:last-child {
  margin-bottom: 0;
  padding-bottom: 0;
  border-bottom: none;
}

.sidebar-link {
  display: block;
  color: var(--color-text);
  text-decoration: none;
  font-size: 0.95rem;
  line-height: 1.4;
}

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

.sidebar-link:focus {
  outline: 2px solid var(--color-link);
  outline-offset: 2px;
  color: var(--color-link);
}

.sidebar-link-title {
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
  text-overflow: ellipsis;
}

.sidebar-date {
  display: block;
  margin-top: var(--space-xs);
  font-size: var(--font-size-small);
  color: var(--color-accent);
}

.sidebar-empty {
  font-size: var(--font-size-small);
  color: var(--color-accent);
  font-style: italic;
}

/* Tablet adjustments (768px - 1023px) */
@media (min-width: 768px) and (max-width: 1023px) {
  .sidebar {
    margin-top: var(--space-2xl);
    padding: var(--space-lg);
    background-color: var(--color-code-bg);
    border-radius: var(--border-radius);
    border-top: none;
  }

  .sidebar-list {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: var(--space-md);
  }

  .sidebar-list li {
    margin-bottom: 0;
    padding-bottom: 0;
    border-bottom: none;
  }
}

/* Desktop sidebar - sticky positioning */
@media (min-width: 1024px) {
  .sidebar {
    position: sticky;
    top: var(--space-lg);
    align-self: start;
    margin-top: 0;
    padding-top: 0;
    border-top: none;
    padding-left: var(--sidebar-padding);
    border-left: var(--sidebar-border);
  }
}

/* ==========================================================================
   Home Page Styles
   ========================================================================== */

.home {
  max-width: var(--content-max-width);
  margin: 0 auto;
}

.site-description {
  font-size: var(--font-size-body);
  color: var(--color-accent);
  margin-bottom: var(--space-2xl);
}

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

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

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

/* Post list title (h2 in listing) */
.post-list-title {
  margin: 0 0 var(--space-sm) 0;
  font-size: var(--font-size-h3);
}

.post-list-title a {
  text-decoration: none;
  color: var(--color-text);
}

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

/* Post list metadata */
.post-list .post-meta {
  margin-bottom: var(--space-sm);
}

.post-list time {
  font-family: var(--font-sans);
  font-size: var(--font-size-small);
  color: var(--color-accent);
}

.post-list .reading-time {
  font-family: var(--font-sans);
  font-size: var(--font-size-small);
  color: var(--color-accent);
}

/* Post excerpt */
.post-excerpt {
  margin: 0;
  color: var(--color-accent);
  font-size: var(--font-size-body);
  line-height: var(--line-height-body);
}

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

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

.pagination-link {
  display: inline-block;
  padding: var(--space-sm) var(--space-md);
  min-height: 44px;
  min-width: 44px;
  line-height: calc(44px - var(--space-sm) * 2);
  text-align: center;
  border: 1px solid var(--color-border);
  border-radius: var(--border-radius);
  color: var(--color-text);
  text-decoration: none;
  transition: border-color var(--transition-speed), color var(--transition-speed);
}

.pagination-link:hover {
  border-color: var(--color-link);
  color: var(--color-link);
  text-decoration: none;
}

.pagination-link:focus {
  outline: 2px solid var(--color-link);
  outline-offset: 2px;
}

.pagination-newer {
  margin-right: auto;
}

.pagination-older {
  margin-left: auto;
}

/* ==========================================================================
   Empty State
   ========================================================================== */

.empty-state {
  text-align: center;
  color: var(--color-accent);
  font-size: var(--font-size-body);
  padding: var(--space-2xl) 0;
  font-style: italic;
}

/* ==========================================================================
   Skip Link (Accessibility)
   ========================================================================== */

.skip-link {
  position: absolute;
  top: -100%;
  left: 0;
  padding: var(--space-sm) var(--space-md);
  background: var(--color-background);
  color: var(--color-link);
  border: 2px solid var(--color-link);
  border-radius: var(--border-radius);
  z-index: 100;
  font-family: var(--font-sans);
  font-size: var(--font-size-small);
  text-decoration: none;
  transition: top 0.2s;
}

.skip-link:focus {
  top: var(--space-sm);
  left: var(--space-sm);
  outline: none;
}

/* ==========================================================================
   Navigation
   ========================================================================== */

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

.site-nav a {
  color: var(--color-text);
  text-decoration: none;
  padding: var(--space-xs) 0;
  min-height: 44px;
  display: inline-flex;
  align-items: center;
}

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

.site-nav a.active {
  color: var(--color-link);
  border-bottom: 2px solid var(--color-link);
}

/* Theme toggle icon visibility */
.theme-toggle {
  min-height: 44px;
  min-width: 44px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
}

.theme-toggle svg {
  width: 20px;
  height: 20px;
}

.icon-moon {
  display: none;
}

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

[data-theme="dark"] .icon-moon {
  display: block;
}

/* ==========================================================================
   Reduced Motion
   ========================================================================== */

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}

/* ==========================================================================
   Responsive Adjustments
   ========================================================================== */

/* Mobile styles (default) */
@media (max-width: 767px) {
  .post-list .post-meta {
    flex-direction: column;
    gap: var(--space-xs);
  }

  .pagination {
    flex-direction: column;
    gap: var(--space-md);
  }

  .pagination-newer,
  .pagination-older {
    margin: 0;
    width: 100%;
    text-align: center;
  }
}

/* Compact navigation on small screens */
@media (max-width: 400px) {
  .site-nav {
    gap: var(--space-sm);
  }
}

/* Desktop styles */
@media (min-width: 768px) {
  main {
    padding: var(--space-2xl) var(--space-lg);
  }

  .header-content,
  .footer-content {
    padding: 0 var(--space-lg);
  }
}