/* ===================================
   Blog Site - Main Styles
   Mobile-first responsive design
   =================================== */

/* ----- CSS Custom Properties ----- */
:root {
  /* Colors */
  --color-primary: #2563eb;
  --color-primary-dark: #1d4ed8;
  --color-text: #1f2937;
  --color-text-light: #6b7280;
  --color-background: #ffffff;
  --color-surface: #f9fafb;
  --color-border: #e5e7eb;
  --color-accent: #3b82f6;
  
  /* Typography */
  --font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;
  --font-family-mono: 'SF Mono', 'Fira Code', 'Consolas', monospace;
  --font-size-base: 1rem;
  --font-size-sm: 0.875rem;
  --font-size-lg: 1.125rem;
  --font-size-xl: 1.25rem;
  --font-size-2xl: 1.5rem;
  --font-size-3xl: 1.875rem;
  --font-size-4xl: 2.25rem;
  --line-height: 1.6;
  --line-height-tight: 1.25;
  
  /* Spacing */
  --spacing-xs: 0.25rem;
  --spacing-sm: 0.5rem;
  --spacing-md: 1rem;
  --spacing-lg: 1.5rem;
  --spacing-xl: 2rem;
  --spacing-2xl: 3rem;
  --spacing-3xl: 4rem;
  
  /* Layout */
  --max-content-width: 70ch;
  --max-page-width: 1200px;
  --header-height: 4rem;
  
  /* Shadows */
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 10px 15px rgba(0, 0, 0, 0.1);
  
  /* Transitions */
  --transition-fast: 150ms ease;
  --transition-normal: 250ms ease;
  
  /* Border radius */
  --radius-sm: 0.25rem;
  --radius-md: 0.5rem;
  --radius-lg: 1rem;
}

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

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

html {
  font-size: 16px;
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-family);
  font-size: var(--font-size-base);
  line-height: var(--line-height);
  color: var(--color-text);
  background-color: var(--color-background);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

img {
  max-width: 100%;
  height: auto;
  display: block;
}

a {
  color: var(--color-primary);
  text-decoration: none;
  transition: color var(--transition-fast);
}

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

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

button {
  font-family: inherit;
  font-size: inherit;
  cursor: pointer;
}

/* ----- Typography ----- */
h1, h2, h3, h4, h5, h6 {
  line-height: var(--line-height-tight);
  font-weight: 600;
  margin-top: var(--spacing-xl);
  margin-bottom: var(--spacing-md);
}

h1 { font-size: var(--font-size-3xl); }
h2 { font-size: var(--font-size-2xl); }
h3 { font-size: var(--font-size-xl); }
h4 { font-size: var(--font-size-lg); }

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

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

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

code {
  font-family: var(--font-family-mono);
  font-size: 0.9em;
  background-color: var(--color-surface);
  padding: 0.15em 0.4em;
  border-radius: var(--radius-sm);
}

pre {
  background-color: var(--color-surface);
  padding: var(--spacing-md);
  border-radius: var(--radius-md);
  overflow-x: auto;
  margin-bottom: var(--spacing-md);
}

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

blockquote {
  border-left: 4px solid var(--color-primary);
  padding-left: var(--spacing-md);
  margin: var(--spacing-md) 0;
  font-style: italic;
  color: var(--color-text-light);
}

/* ----- Layout ----- */
.container {
  width: 100%;
  max-width: var(--max-page-width);
  margin: 0 auto;
  padding: 0 var(--spacing-md);
}

main {
  flex: 1;
  padding: var(--spacing-xl) 0;
}

/* ----- Skip Link ----- */
.skip-link {
  position: absolute;
  top: -100%;
  left: 0;
  background: var(--color-primary);
  color: white;
  padding: var(--spacing-sm) var(--spacing-md);
  z-index: 1000;
}

.skip-link:focus {
  top: 0;
}

/* ----- Header ----- */
.site-header {
  background-color: var(--color-background);
  border-bottom: 1px solid var(--color-border);
  position: sticky;
  top: 0;
  z-index: 100;
}

.site-header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: var(--header-height);
  padding-top: var(--spacing-sm);
  padding-bottom: var(--spacing-sm);
}

.site-branding {
  display: flex;
  flex-direction: column;
  gap: 0.125rem;
}

.site-title {
  font-size: var(--font-size-xl);
  font-weight: 700;
  color: var(--color-text);
  line-height: 1.2;
}

.site-title:hover {
  color: var(--color-primary);
  text-decoration: none;
}

.site-tagline {
  font-size: var(--font-size-sm);
  color: var(--color-text-light);
  margin: 0;
  font-weight: 400;
}

.site-nav {
  display: flex;
  gap: var(--spacing-md);
}

.site-nav a {
  color: var(--color-text);
  font-weight: 500;
}

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

/* ----- Footer ----- */
.site-footer {
  background-color: var(--color-surface);
  border-top: 1px solid var(--color-border);
  padding: var(--spacing-xl) 0;
  margin-top: auto;
}

.site-footer .container {
  text-align: center;
  color: var(--color-text-light);
  font-size: var(--font-size-sm);
}

/* ----- Post Grid ----- */
.post-grid {
  display: grid;
  gap: var(--spacing-xl);
  grid-template-columns: 1fr;
}

/* ----- Post Card ----- */
.post-card {
  background: var(--color-background);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  transition: box-shadow var(--transition-normal), transform var(--transition-normal);
}

.post-card:hover {
  box-shadow: var(--shadow-lg);
  transform: translateY(-2px);
}

.post-card__image-link {
  display: block;
}

.post-card__image {
  aspect-ratio: 16 / 9;
  object-fit: cover;
  width: 100%;
  background-color: var(--color-surface);
  transition: transform var(--transition-normal);
}

.post-card__image-link:hover .post-card__image {
  transform: scale(1.02);
}

.post-card__content {
  padding: var(--spacing-lg);
}

.post-card__title {
  font-size: var(--font-size-xl);
  margin: 0 0 var(--spacing-sm);
}

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

.post-card__title a:hover {
  color: var(--color-primary);
  text-decoration: none;
}

.post-card__meta {
  font-size: var(--font-size-sm);
  color: var(--color-text-light);
  margin-bottom: var(--spacing-sm);
}

.post-card__summary {
  color: var(--color-text-light);
  margin-bottom: var(--spacing-md);
}

.post-card__tags {
  display: flex;
  flex-wrap: wrap;
  gap: var(--spacing-xs);
}

.tag {
  display: inline-block;
  background-color: var(--color-surface);
  color: var(--color-text-light);
  padding: var(--spacing-xs) var(--spacing-sm);
  border-radius: var(--radius-sm);
  font-size: var(--font-size-sm);
  transition: background-color var(--transition-fast);
}

.tag:hover {
  background-color: var(--color-primary);
  color: white;
  text-decoration: none;
}

/* ----- Controls (Sort/Filter) ----- */
.controls {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-md);
  margin-bottom: var(--spacing-xl);
  padding: var(--spacing-md);
  background-color: var(--color-surface);
  border-radius: var(--radius-md);
}

.controls__group {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-xs);
}

.controls__label {
  font-size: var(--font-size-sm);
  font-weight: 500;
  color: var(--color-text-light);
}

.controls__select {
  padding: var(--spacing-sm) var(--spacing-md);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  font-size: var(--font-size-base);
  background-color: var(--color-background);
  cursor: pointer;
}

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

/* ----- Single Post ----- */
.post-hero {
  margin-bottom: var(--spacing-xl);
}

.post-hero__image {
  width: 100%;
  max-height: 400px;
  object-fit: contain;
  border-radius: var(--radius-lg);
}

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

.post-header__title {
  font-size: var(--font-size-3xl);
  margin: 0 0 var(--spacing-md);
}

.post-header__meta {
  color: var(--color-text-light);
  font-size: var(--font-size-sm);
}

.post-content {
  width: 100%;
}

.post-content img {
  border-radius: var(--radius-md);
  margin: var(--spacing-lg) 0;
}

/* Post Image Layout Options */
.post-content .post-image {
  max-width: 400px;
  height: auto;
  border-radius: var(--radius-md);
  margin: var(--spacing-lg) 0;
}

/* Centered image - text above/below only */
.post-content .post-image--center {
  display: block;
  margin-left: auto;
  margin-right: auto;
}

/* Float image - text wraps around */
.post-content .post-image--float {
  float: left;
  margin-top: 0.3em !important; /* Align image with text top */
  margin-right: 1.5rem !important;
  margin-bottom: var(--spacing-md) !important;
  margin-left: 0 !important;
}

/* Ensure text beside float aligns properly */
.post-content .post-image--float + p,
.post-content .post-image--float + ul,
.post-content .post-image--float + ol {
  margin-top: 0;
}

/* Clear floats after paragraphs following floated images */
.post-content::after {
  content: '';
  display: table;
  clear: both;
}

.post-content h2:first-child,
.post-content h3:first-child {
  margin-top: 0;
}

/* ----- Post Navigation ----- */
.post-nav {
  display: flex;
  justify-content: space-between;
  gap: var(--spacing-md);
  margin-top: var(--spacing-2xl);
  padding-top: var(--spacing-xl);
  border-top: 1px solid var(--color-border);
}

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

.post-nav__link--next {
  text-align: right;
  margin-left: auto;
}

.post-nav__label {
  font-size: var(--font-size-sm);
  color: var(--color-text-light);
}

.post-nav__title {
  font-weight: 500;
}

/* ----- Related Posts ----- */
.related-posts {
  margin-top: var(--spacing-2xl);
  padding-top: var(--spacing-xl);
  border-top: 1px solid var(--color-border);
}

.related-posts__title {
  font-size: var(--font-size-xl);
  margin-bottom: var(--spacing-lg);
}

.related-posts__grid {
  display: grid;
  gap: var(--spacing-md);
  grid-template-columns: 1fr;
}

/* ----- No JavaScript Fallback ----- */
.no-js-message {
  text-align: center;
  padding: var(--spacing-2xl);
  background-color: var(--color-surface);
  border-radius: var(--radius-md);
}

/* ----- Loading State ----- */
.loading {
  text-align: center;
  padding: var(--spacing-2xl);
  color: var(--color-text-light);
}

/* ----- Empty State ----- */
.empty-state {
  text-align: center;
  padding: var(--spacing-2xl);
  color: var(--color-text-light);
}

/* ===================================
   Responsive Breakpoints
   =================================== */

/* Tablet (768px and up) */
@media (min-width: 768px) {
  :root {
    --font-size-3xl: 2.25rem;
    --font-size-4xl: 3rem;
  }
  
  .post-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  
  .controls {
    flex-direction: row;
    align-items: flex-end;
  }
  
  .controls__group {
    flex: 1;
  }
  
  .related-posts__grid {
    grid-template-columns: repeat(2, 1fr);
  }
  
  .post-hero__image {
    max-height: 500px;
  }
}

/* Desktop (1024px and up) */
@media (min-width: 1024px) {
  .post-grid {
    grid-template-columns: repeat(3, 1fr);
  }
  
  .related-posts__grid {
    grid-template-columns: repeat(3, 1fr);
  }
  
  .post-header__title {
    font-size: var(--font-size-4xl);
  }
}

/* ----- Image Lightbox ----- */
.lightbox {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.9);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 1000;
  opacity: 0;
  visibility: hidden;
  transition: opacity var(--transition-normal), visibility var(--transition-normal);
}

.lightbox--open {
  opacity: 1;
  visibility: visible;
}

.lightbox__image {
  max-width: 90vw;
  max-height: 90vh;
  object-fit: contain;
  border-radius: var(--radius-md);
  box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.5);
}

.lightbox__close {
  position: absolute;
  top: var(--spacing-lg);
  right: var(--spacing-lg);
  background: transparent;
  border: none;
  color: white;
  font-size: 2.5rem;
  cursor: pointer;
  padding: var(--spacing-sm);
  line-height: 1;
  opacity: 0.8;
  transition: opacity var(--transition-fast);
}

.lightbox__close:hover,
.lightbox__close:focus {
  opacity: 1;
}

/* Make content images show pointer cursor to indicate clickability */
.post-content .post-image {
  cursor: zoom-in;
}