/* ============================================
   Minimal Theme v2 - Refined & Elegant
   ============================================ */

:root {
  /* Refined color palette */
  --bg: #fafaf9;
  --bg-elevated: #ffffff;
  --bg-subtle: #f5f5f4;
  --text: #1c1917;
  --text-secondary: #57534e;
  --text-tertiary: #a8a29e;
  --line: #e7e5e4;
  --line-soft: #f0efed;
  --accent: #18181b;
  --accent-soft: #fafaf9;
  
  /* Typography */
  --font-serif: 'Source Serif Pro', 'Noto Serif SC', 'Songti SC', Georgia, serif;
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'PingFang SC', sans-serif;
  --font-mono: 'JetBrains Mono', 'SF Mono', Menlo, monospace;
  
  /* Spacing scale */
  --space-xs: 0.5rem;
  --space-sm: 1rem;
  --space-md: 1.5rem;
  --space-lg: 3rem;
  --space-xl: 5rem;
  --space-2xl: 7rem;
  
  --max-width: 880px;
  --header-height: 72px;
  
  --transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-fast: 0.15s cubic-bezier(0.4, 0, 0.2, 1);
}

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

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

body {
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.7;
  color: var(--text);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  font-feature-settings: 'kern', 'liga', 'calt';
}

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

a:hover {
  opacity: 0.6;
}

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

::selection {
  background: var(--text);
  color: var(--bg);
}

/* Layout */
.container {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

.main {
  flex: 1;
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--space-md) var(--space-2xl);
}

/* ============================================
   Header - Minimal & Floating
   ============================================ */
.header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(250, 250, 249, 0.75);
  backdrop-filter: saturate(180%) blur(20px);
  -webkit-backdrop-filter: saturate(180%) blur(20px);
}

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

.logo {
  font-family: var(--font-serif);
  font-size: 1.25rem;
  font-weight: 600;
  color: var(--text);
  letter-spacing: -0.02em;
}

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

.nav-link {
  position: relative;
  font-size: 0.875rem;
  font-weight: 400;
  color: var(--text-secondary);
  letter-spacing: 0.01em;
}

.nav-link.active {
  color: var(--text);
}

.nav-link::after {
  content: '';
  position: absolute;
  bottom: -4px;
  left: 0;
  right: 0;
  height: 1px;
  background: var(--text);
  transform: scaleX(0);
  transform-origin: center;
  transition: transform var(--transition);
}

.nav-link:hover {
  opacity: 1;
  color: var(--text);
}

.nav-link:hover::after {
  transform: scaleX(1);
}

.menu-toggle {
  display: none;
  flex-direction: column;
  gap: 4px;
  width: 32px;
  height: 32px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 6px;
  justify-content: center;
}

.menu-toggle span {
  display: block;
  width: 100%;
  height: 1.5px;
  background: var(--text);
  transition: transform var(--transition), opacity var(--transition);
}

.menu-toggle.active span:nth-child(1) {
  transform: translateY(5.5px) rotate(45deg);
}

.menu-toggle.active span:nth-child(2) {
  opacity: 0;
}

.menu-toggle.active span:nth-child(3) {
  transform: translateY(-5.5px) rotate(-45deg);
}

/* ============================================
   Hero - Minimal & Centered
   ============================================ */
.hero {
  padding: var(--space-2xl) 0 var(--space-xl);
  text-align: left;
  animation: fadeIn 0.8s ease forwards;
}

.hero-title {
  font-family: var(--font-serif);
  font-size: clamp(2rem, 5vw, 3rem);
  font-weight: 500;
  letter-spacing: -0.03em;
  line-height: 1.1;
  color: var(--text);
  margin-bottom: var(--space-sm);
}

.hero-subtitle {
  font-size: 1.0625rem;
  color: var(--text-secondary);
  font-weight: 400;
  max-width: 480px;
}

/* ============================================
   Section Title
   ============================================ */
.section-title {
  font-family: var(--font-sans);
  font-size: 0.75rem;
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--text-tertiary);
  margin-bottom: var(--space-md);
  padding-bottom: var(--space-sm);
  border-bottom: 1px solid var(--line);
}

/* ============================================
   Post List - Refined
   ============================================ */
.post-list {
  list-style: none;
  margin-top: var(--space-md);
}

.post-item {
  padding: var(--space-md) 0;
  border-bottom: 1px solid var(--line-soft);
  transition: padding var(--transition);
}

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

.post-item:hover {
  padding-left: var(--space-xs);
}

.post-title {
  font-family: var(--font-serif);
  font-size: 1.375rem;
  font-weight: 500;
  letter-spacing: -0.01em;
  line-height: 1.3;
  margin-bottom: var(--space-xs);
}

.post-title a {
  color: var(--text);
  background-image: linear-gradient(var(--text), var(--text));
  background-position: 0 100%;
  background-repeat: no-repeat;
  background-size: 0 1px;
  transition: background-size var(--transition), opacity var(--transition-fast);
}

.post-item:hover .post-title a {
  background-size: 100% 1px;
  opacity: 1;
}

.post-meta {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  font-size: 0.8125rem;
  color: var(--text-tertiary);
  font-family: var(--font-mono);
  letter-spacing: -0.01em;
}

.post-meta-separator {
  width: 3px;
  height: 3px;
  background: var(--text-tertiary);
  border-radius: 50%;
  opacity: 0.5;
}

.post-excerpt {
  margin-top: var(--space-xs);
  color: var(--text-secondary);
  font-size: 0.9375rem;
  line-height: 1.6;
  max-width: 600px;
}

/* ============================================
   Single Post - Editorial
   ============================================ */
.post-header {
  margin-bottom: var(--space-lg);
  padding-bottom: var(--space-md);
  border-bottom: 1px solid var(--line);
}

.post-header .post-title {
  font-family: var(--font-serif);
  font-size: clamp(1.75rem, 4vw, 2.5rem);
  font-weight: 500;
  letter-spacing: -0.02em;
  line-height: 1.2;
  margin-bottom: var(--space-sm);
}

.post-header .post-meta {
  margin-bottom: 0;
}

.post-content {
  font-size: 1.0625rem;
  line-height: 1.85;
  color: var(--text);
}

.post-content > * + * {
  margin-top: 1.5em;
}

.post-content img {
  border-radius: 4px;
  margin: var(--space-lg) 0;
}

/* Inline links in posts */
.post-content a {
  color: var(--text);
  text-decoration: none;
  border-bottom: 1px solid var(--line);
  transition: border-color var(--transition-fast);
}

.post-content a:hover {
  border-bottom-color: var(--text);
  opacity: 1;
}

/* Headings in posts */
.post-content h2 {
  font-family: var(--font-serif);
  font-size: 1.5rem;
  font-weight: 500;
  letter-spacing: -0.01em;
  margin-top: 2.5em;
  margin-bottom: 0.5em;
}

.post-content h3 {
  font-family: var(--font-serif);
  font-size: 1.25rem;
  font-weight: 500;
  margin-top: 2em;
  margin-bottom: 0.5em;
}

/* Code */
.post-content code {
  font-family: var(--font-mono);
  font-size: 0.875em;
  background: var(--bg-subtle);
  padding: 0.15em 0.4em;
  border-radius: 3px;
  color: var(--text);
}

.post-content pre {
  background: var(--bg-subtle);
  border: 1px solid var(--line-soft);
  border-radius: 6px;
  padding: var(--space-md);
  overflow-x: auto;
  font-size: 0.875rem;
  line-height: 1.7;
}

.post-content pre code {
  background: none;
  padding: 0;
  font-size: inherit;
}

/* Blockquote */
.post-content blockquote {
  border-left: 2px solid var(--text);
  padding-left: var(--space-md);
  font-style: italic;
  color: var(--text-secondary);
}

/* Lists */
.post-content ul, .post-content ol {
  padding-left: 1.5em;
}

.post-content li + li {
  margin-top: 0.4em;
}

/* ============================================
   Archive Page
   ============================================ */
.archive-year {
  margin-bottom: var(--space-lg);
}

.archive-year-title {
  font-family: var(--font-sans);
  font-size: 0.875rem;
  font-weight: 500;
  letter-spacing: 0.05em;
  color: var(--text-tertiary);
  margin-bottom: var(--space-md);
}

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

.archive-item {
  display: flex;
  align-items: baseline;
  gap: var(--space-md);
  padding: var(--space-sm) 0;
  border-bottom: 1px solid var(--line-soft);
  transition: padding-left var(--transition);
}

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

.archive-item:hover {
  padding-left: var(--space-xs);
}

.archive-date {
  flex-shrink: 0;
  width: 80px;
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  color: var(--text-tertiary);
  letter-spacing: -0.01em;
}

.archive-title {
  font-family: var(--font-serif);
  font-size: 1.0625rem;
  font-weight: 400;
  color: var(--text);
}

/* ============================================
   Tags Page
   ============================================ */
.tag-cloud {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-sm);
  margin-top: var(--space-md);
}

.tag-item {
  display: inline-flex;
  align-items: baseline;
  gap: 6px;
  padding: 8px 16px;
  font-size: 0.9375rem;
  background: var(--bg-elevated);
  border: 1px solid var(--line);
  border-radius: 999px;
  color: var(--text-secondary);
  transition: all var(--transition-fast);
}

.tag-item:hover {
  border-color: var(--text);
  color: var(--text);
  transform: translateY(-1px);
}

.tag-count {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--text-tertiary);
}

/* ============================================
   Categories Page
   ============================================ */
.category-list {
  display: flex;
  flex-direction: column;
  gap: 1px;
  margin-top: var(--space-md);
  background: var(--line-soft);
  border: 1px solid var(--line-soft);
  border-radius: 6px;
  overflow: hidden;
}

.category-item {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: var(--space-md) var(--space-md);
  background: var(--bg-elevated);
  transition: all var(--transition-fast);
}

.category-item:hover {
  background: var(--bg-subtle);
  padding-left: calc(var(--space-md) + 8px);
}

.category-item:hover .category-name {
  color: var(--text);
}

.category-name {
  font-family: var(--font-serif);
  font-size: 1.0625rem;
  color: var(--text);
  transition: color var(--transition-fast);
}

.category-count {
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  color: var(--text-tertiary);
}

/* ============================================
   About Page
   ============================================ */
.about-content {
  font-size: 1.0625rem;
  line-height: 1.85;
  max-width: 600px;
}

.about-content > * + * {
  margin-top: 1.5em;
}

/* ============================================
   Footer - Minimal
   ============================================ */
.footer {
  padding: var(--space-lg) var(--space-md);
  margin-top: var(--space-xl);
  border-top: 1px solid var(--line-soft);
}

.footer-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 0.8125rem;
  color: var(--text-tertiary);
  font-family: var(--font-mono);
  letter-spacing: -0.01em;
}

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

.footer a:hover {
  color: var(--text);
  opacity: 1;
}

/* ============================================
   Pagination
   ============================================ */
.pagination {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-top: var(--space-xl);
  padding-top: var(--space-md);
  border-top: 1px solid var(--line-soft);
}

.pagination-item {
  font-size: 0.875rem;
  color: var(--text-secondary);
  font-family: var(--font-mono);
}

.pagination-item:hover {
  color: var(--text);
  opacity: 1;
}

.pagination-info {
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  color: var(--text-tertiary);
}

/* ============================================
   Animations
   ============================================ */
@keyframes fadeIn {
  from {
    opacity: 0;
    transform: translateY(8px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes slideUp {
  from {
    opacity: 0;
    transform: translateY(12px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.post-item {
  animation: slideUp 0.6s ease forwards;
  opacity: 0;
}

.post-item:nth-child(1) { animation-delay: 0.05s; }
.post-item:nth-child(2) { animation-delay: 0.1s; }
.post-item:nth-child(3) { animation-delay: 0.15s; }
.post-item:nth-child(4) { animation-delay: 0.2s; }
.post-item:nth-child(5) { animation-delay: 0.25s; }
.post-item:nth-child(6) { animation-delay: 0.3s; }
.post-item:nth-child(7) { animation-delay: 0.35s; }
.post-item:nth-child(8) { animation-delay: 0.4s; }

/* ============================================
   Responsive
   ============================================ */
@media (max-width: 768px) {
  :root {
    --space-2xl: 4rem;
    --space-xl: 3rem;
    --space-lg: 2rem;
  }
  
  .header-inner {
    padding: 0 var(--space-sm);
  }
  
  .nav {
    display: none;
    position: absolute;
    top: var(--header-height);
    left: 0;
    right: 0;
    flex-direction: column;
    gap: var(--space-sm);
    padding: var(--space-md);
    background: var(--bg);
    border-bottom: 1px solid var(--line);
  }
  
  .nav.active {
    display: flex;
  }
  
  .menu-toggle {
    display: flex;
  }
  
  .main {
    padding: 0 var(--space-sm) var(--space-2xl);
  }
  
  .post-item:hover {
    padding-left: 0;
  }
  
  .footer-inner {
    flex-direction: column;
    gap: var(--space-xs);
    text-align: center;
  }
}

@media (max-width: 480px) {
  .archive-item {
    flex-direction: column;
    gap: 4px;
  }
  
  .archive-date {
    width: auto;
  }
}

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

:focus-visible {
  outline: 1px solid var(--text);
  outline-offset: 4px;
}