/* ==========================================================================
   Blog Site - Mobile-First Responsive Stylesheet
   ========================================================================== */

/* --------------------------------------------------------------------------
   CSS Custom Properties (Variables)
   -------------------------------------------------------------------------- */
:root {
  /* Colors */
  --color-bg: #f0d1c7;
  --color-bg-light: #f8e5de;
  --color-bg-dark: #dcb5a8;
  --color-text: #1a1a1a;
  --color-text-muted: #4a4a4a;
  --color-accent: #8b4a3c;
  --color-accent-hover: #6d3a2f;
  --color-white: #ffffff;
  --color-border: rgba(0, 0, 0, 0.1);
  
  /* Typography */
  --font-heading: 'Playfair Display', Georgia, serif;
  --font-body: 'Source Sans 3', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', monospace;
  
  /* Spacing Scale */
  --space-xs: 0.25rem;
  --space-sm: 0.5rem;
  --space-md: 1rem;
  --space-lg: 1.5rem;
  --space-xl: 2rem;
  --space-2xl: 3rem;
  --space-3xl: 4rem;
  
  /* Font Sizes - Mobile First */
  --text-xs: 0.75rem;
  --text-sm: 0.875rem;
  --text-base: 1rem;
  --text-lg: 1.125rem;
  --text-xl: 1.25rem;
  --text-2xl: 1.5rem;
  --text-3xl: 2rem;
  --text-4xl: 2.5rem;
  
  /* Line Heights */
  --leading-tight: 1.25;
  --leading-normal: 1.6;
  --leading-relaxed: 1.75;
  
  /* Shadows */
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.07);
  --shadow-lg: 0 10px 25px rgba(0, 0, 0, 0.1);
  
  /* Transitions */
  --transition-fast: 150ms ease;
  --transition-base: 250ms ease;
  --transition-slow: 400ms ease;
  
  /* Border Radius */
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;
  
  /* Max Widths */
  --max-width-content: 800px;
  --max-width-wide: 1200px;
}

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

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

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

/* --------------------------------------------------------------------------
   Typography
   -------------------------------------------------------------------------- */
h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-heading);
  font-weight: 700;
  line-height: var(--leading-tight);
  color: var(--color-text);
}

h1 {
  font-size: var(--text-3xl);
  letter-spacing: -0.02em;
}

h2 {
  font-size: var(--text-2xl);
  letter-spacing: -0.01em;
}

h3 {
  font-size: var(--text-xl);
}

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

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

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

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

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

.container--wide {
  max-width: var(--max-width-wide);
}

/* --------------------------------------------------------------------------
   Header
   -------------------------------------------------------------------------- */
.site-header {
  padding: var(--space-xl) 0;
  text-align: center;
  border-bottom: 1px solid var(--color-border);
  margin-bottom: var(--space-xl);
  animation: fadeInDown 0.6s ease-out;
}

.site-title {
  font-size: var(--text-3xl);
  font-weight: 700;
  margin-bottom: var(--space-sm);
}

.site-title a {
  color: var(--color-text);
  text-decoration: none;
  transition: opacity var(--transition-base);
}

.site-title a:hover {
  opacity: 0.8;
  text-decoration: none;
}

.site-tagline {
  font-size: var(--text-base);
  color: var(--color-text-muted);
  font-style: italic;
}

/* --------------------------------------------------------------------------
   Navigation
   -------------------------------------------------------------------------- */
.site-nav {
  margin-top: var(--space-lg);
}

.site-nav ul {
  list-style: none;
  display: flex;
  justify-content: center;
  gap: var(--space-lg);
  flex-wrap: wrap;
}

.site-nav a {
  font-size: var(--text-sm);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  font-weight: 600;
  padding: var(--space-sm) var(--space-md);
  border-radius: var(--radius-sm);
  transition: background-color var(--transition-fast), color var(--transition-fast);
}

.site-nav a:hover {
  background-color: var(--color-accent);
  color: var(--color-white);
  text-decoration: none;
}

/* --------------------------------------------------------------------------
   Main Content
   -------------------------------------------------------------------------- */
.main-content {
  padding: var(--space-md) 0 var(--space-3xl);
}

/* --------------------------------------------------------------------------
   Post List (Landing Page)
   -------------------------------------------------------------------------- */
.posts-list {
  display: flex;
  flex-direction: column;
  gap: var(--space-xl);
}

.post-card {
  background: var(--color-white);
  border-radius: var(--radius-lg);
  padding: var(--space-lg);
  box-shadow: var(--shadow-md);
  transition: transform var(--transition-base), box-shadow var(--transition-base);
  animation: fadeInUp 0.5s ease-out backwards;
}

.post-card:nth-child(1) { animation-delay: 0.1s; }
.post-card:nth-child(2) { animation-delay: 0.2s; }
.post-card:nth-child(3) { animation-delay: 0.3s; }
.post-card:nth-child(4) { animation-delay: 0.4s; }
.post-card:nth-child(5) { animation-delay: 0.5s; }

.post-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
}

.post-card a {
  display: block;
  color: inherit;
  text-decoration: none;
}

.post-card a:hover {
  text-decoration: none;
}

.post-card__date {
  font-size: var(--text-xs);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--color-text-muted);
  margin-bottom: var(--space-sm);
  display: block;
}

.post-card__title {
  font-size: var(--text-xl);
  margin-bottom: var(--space-sm);
  transition: color var(--transition-fast);
}

.post-card:hover .post-card__title {
  color: var(--color-accent);
}

.post-card__excerpt {
  color: var(--color-text-muted);
  font-size: var(--text-sm);
  line-height: var(--leading-relaxed);
  margin: 0;
}

.post-card__read-more {
  display: inline-flex;
  align-items: center;
  gap: var(--space-xs);
  margin-top: var(--space-md);
  font-size: var(--text-sm);
  font-weight: 600;
  color: var(--color-accent);
  transition: gap var(--transition-fast);
}

.post-card:hover .post-card__read-more {
  gap: var(--space-sm);
}

.post-card__read-more::after {
  content: '→';
}

/* --------------------------------------------------------------------------
   Single Post Page
   -------------------------------------------------------------------------- */
.post-header {
  margin-bottom: var(--space-xl);
  padding-bottom: var(--space-lg);
  border-bottom: 1px solid var(--color-border);
  animation: fadeInDown 0.5s ease-out;
}

.post-meta {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-md);
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  margin-bottom: var(--space-md);
}

.post-meta__item {
  display: flex;
  align-items: center;
  gap: var(--space-xs);
}

.post-title {
  font-size: var(--text-3xl);
  line-height: 1.2;
}

.post-content {
  animation: fadeIn 0.6s ease-out 0.2s backwards;
}

.post-content h2 {
  margin-top: var(--space-2xl);
  margin-bottom: var(--space-md);
}

.post-content h3 {
  margin-top: var(--space-xl);
  margin-bottom: var(--space-md);
}

.post-content p {
  margin-bottom: var(--space-lg);
  line-height: var(--leading-relaxed);
}

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

.post-content li {
  margin-bottom: var(--space-sm);
  line-height: var(--leading-relaxed);
}

.post-content blockquote {
  border-left: 4px solid var(--color-accent);
  padding-left: var(--space-lg);
  margin: var(--space-xl) 0;
  font-style: italic;
  color: var(--color-text-muted);
}

.post-content code {
  font-family: var(--font-mono);
  font-size: 0.9em;
  background: var(--color-bg-dark);
  padding: 0.2em 0.4em;
  border-radius: var(--radius-sm);
}

.post-content pre {
  background: var(--color-text);
  color: var(--color-bg-light);
  padding: var(--space-lg);
  border-radius: var(--radius-md);
  overflow-x: auto;
  margin: var(--space-xl) 0;
}

.post-content pre code {
  background: transparent;
  padding: 0;
  color: inherit;
}

.post-content img {
  border-radius: var(--radius-md);
  margin: var(--space-xl) 0;
  box-shadow: var(--shadow-md);
}

/* Back Link */
.back-link {
  display: inline-flex;
  align-items: center;
  gap: var(--space-sm);
  margin-bottom: var(--space-xl);
  font-size: var(--text-sm);
  font-weight: 600;
  color: var(--color-accent);
  transition: gap var(--transition-fast);
}

.back-link:hover {
  gap: var(--space-md);
  text-decoration: none;
}

.back-link::before {
  content: '←';
}

/* --------------------------------------------------------------------------
   Footer
   -------------------------------------------------------------------------- */
.site-footer {
  padding: var(--space-xl) 0;
  text-align: center;
  border-top: 1px solid var(--color-border);
  margin-top: var(--space-3xl);
}

.site-footer p {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  margin: 0;
}

/* --------------------------------------------------------------------------
   Animations
   -------------------------------------------------------------------------- */
@keyframes fadeIn {
  from {
    opacity: 0;
  }
  to {
    opacity: 1;
  }
}

@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes fadeInDown {
  from {
    opacity: 0;
    transform: translateY(-20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

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

.text-center {
  text-align: center;
}

.mt-xl {
  margin-top: var(--space-xl);
}

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

/* --------------------------------------------------------------------------
   Empty State
   -------------------------------------------------------------------------- */
.empty-state {
  text-align: center;
  padding: var(--space-3xl) var(--space-lg);
  color: var(--color-text-muted);
}

.empty-state__icon {
  font-size: var(--text-4xl);
  margin-bottom: var(--space-lg);
  opacity: 0.5;
}

/* --------------------------------------------------------------------------
   Responsive Design - Tablet (768px+)
   -------------------------------------------------------------------------- */
@media (min-width: 768px) {
  :root {
    --text-3xl: 2.5rem;
    --text-4xl: 3rem;
    --max-width-content: 880px;
  }
  
  .container {
    padding: 0 var(--space-xl);
  }
  
  .site-header {
    padding: var(--space-2xl) 0;
    margin-bottom: var(--space-2xl);
  }
  
  .site-title {
    font-size: var(--text-4xl);
  }
  
  .post-card {
    padding: var(--space-xl);
  }
  
  .post-card__title {
    font-size: var(--text-2xl);
  }
  
  .post-card__excerpt {
    font-size: var(--text-base);
  }
  
  .post-title {
    font-size: var(--text-4xl);
  }
  
  .main-content {
    padding: var(--space-xl) 0 var(--space-3xl);
  }
}

/* --------------------------------------------------------------------------
   Responsive Design - Desktop (1024px+)
   -------------------------------------------------------------------------- */
@media (min-width: 1024px) {
  :root {
    --text-3xl: 2.75rem;
    --text-4xl: 3.5rem;
    --max-width-content: 960px;
  }
  
  .site-header {
    padding: var(--space-3xl) 0;
  }
  
  .posts-list {
    gap: var(--space-2xl);
  }
  
  .post-card {
    padding: var(--space-2xl);
  }
  
  .post-content {
    font-size: var(--text-lg);
  }
}

/* --------------------------------------------------------------------------
   Responsive Design - Large Desktop (1280px+)
   -------------------------------------------------------------------------- */
@media (min-width: 1280px) {
  :root {
    --max-width-content: 1040px;
  }
  
  .container {
    padding: 0 var(--space-2xl);
  }
}

/* --------------------------------------------------------------------------
   Print Styles
   -------------------------------------------------------------------------- */
@media print {
  body {
    background: white;
    color: black;
  }
  
  .site-nav,
  .back-link,
  .site-footer {
    display: none;
  }
  
  .post-card {
    box-shadow: none;
    border: 1px solid #ccc;
    break-inside: avoid;
  }
}