/* ============================================
   Personal Site — Main Stylesheet
   Design: Minimalist, text-focused, thin typography
   Primary: Olive Green (#556B2F)
   ============================================ */

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

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

body {
  font-family: 'Inter', 'Noto Sans SC', -apple-system, BlinkMacSystemFont, sans-serif;
  font-weight: 300;
  font-size: 1rem;
  line-height: 1.7;
  color: var(--text-primary);
  background-color: var(--bg-primary);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* ---------- CSS Custom Properties ---------- */
:root {
  --bg-primary: #FAFAF7;
  --bg-secondary: #F0F0EC;
  --text-primary: #1A1A1A;
  --text-secondary: #6B6B6B;
  --text-tertiary: #9A9A94;
  --accent: #556B2F;
  --accent-hover: #4A5E28;
  --accent-light: #6B8F3E;
  --divider: #E0E0DC;
  --divider-dark: #2A2A2A;
  --max-width: 680px;
  --nav-height: 56px;
  --spacing-xs: 0.5rem;
  --spacing-sm: 1rem;
  --spacing-md: 1.5rem;
  --spacing-lg: 2.5rem;
  --spacing-xl: 4rem;
}

[data-theme="dark"] {
  --bg-primary: #1A1A1A;
  --bg-secondary: #222222;
  --text-primary: #E8E8E8;
  --text-secondary: #A0A0A0;
  --text-tertiary: #6B6B6B;
  --accent: #8FBC5A;
  --accent-hover: #A0CC6B;
  --accent-light: #6B8F3E;
  --divider: #2A2A2A;
  --divider-dark: #E0E0DC;
}

/* ---------- Typography ---------- */
h1, h2, h3, h4, h5, h6 {
  font-weight: 400;
  line-height: 1.3;
  color: var(--text-primary);
}

h1 { font-size: 2rem; letter-spacing: -0.02em; }
h2 { font-size: 1.5rem; letter-spacing: -0.01em; }
h3 { font-size: 1.25rem; }
h4 { font-size: 1.1rem; }

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

a {
  color: var(--accent);
  text-decoration: none;
  border-bottom: 1px solid transparent;
}

a:hover {
  color: var(--accent-hover);
  border-bottom-color: var(--accent-hover);
}

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

/* ---------- Navigation ---------- */
.site-nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--nav-height);
  background-color: var(--bg-primary);
  border-bottom: 1px solid var(--divider);
  z-index: 100;
}

.site-nav .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
}

.nav-brand {
  font-size: 0.9rem;
  font-weight: 500;
  letter-spacing: 0.02em;
  color: var(--text-primary);
  border-bottom: none;
}

.nav-brand:hover {
  color: var(--accent);
  border-bottom: none;
}

.nav-links {
  display: flex;
  list-style: none;
  gap: var(--spacing-md);
}

.nav-links a {
  font-size: 0.85rem;
  font-weight: 400;
  color: var(--text-secondary);
  border-bottom: none;
  padding: 0.25rem 0;
}

.nav-links a:hover,
.nav-links a.active {
  color: var(--accent);
  border-bottom: 1px solid var(--accent);
}

.nav-theme-toggle {
  background: none;
  border: none;
  cursor: pointer;
  font-size: 0.85rem;
  color: var(--text-secondary);
  padding: 0.25rem 0.5rem;
  font-family: inherit;
}

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

/* ---------- Main Content ---------- */
.site-main {
  padding-top: calc(var(--nav-height) + var(--spacing-xl));
  min-height: 100vh;
}

/* ---------- Hero Section ---------- */
.hero {
  padding: var(--spacing-xl) 0;
  border-bottom: 1px solid var(--divider);
}

.hero h1 {
  font-size: 2.5rem;
  font-weight: 300;
  margin-bottom: var(--spacing-sm);
  letter-spacing: -0.03em;
}

.hero .subtitle {
  font-size: 1.1rem;
  color: var(--text-secondary);
  margin-bottom: var(--spacing-md);
  font-weight: 300;
}

.hero .bio {
  font-size: 1rem;
  color: var(--text-secondary);
  max-width: 560px;
  line-height: 1.8;
}

/* ---------- Section ---------- */
.section {
  padding: var(--spacing-xl) 0;
  border-bottom: 1px solid var(--divider);
}

.section:last-child {
  border-bottom: none;
}

.section-title {
  font-size: 0.8rem;
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-tertiary);
  margin-bottom: var(--spacing-lg);
}

/* ---------- Skills / Tags ---------- */
.tag-list {
  display: flex;
  flex-wrap: wrap;
  gap: var(--spacing-xs);
  list-style: none;
}

.tag-list li {
  font-size: 0.8rem;
  font-weight: 400;
  color: var(--text-secondary);
  background-color: var(--bg-secondary);
  padding: 0.3rem 0.75rem;
  border: 1px solid var(--divider);
}

/* ---------- Project List ---------- */
.project-list {
  list-style: none;
}

.project-list li {
  padding: var(--spacing-md) 0;
  border-bottom: 1px solid var(--divider);
}

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

.project-list .project-title {
  font-size: 1rem;
  font-weight: 400;
  color: var(--text-primary);
  margin-bottom: 0.25rem;
}

.project-list .project-desc {
  font-size: 0.9rem;
  color: var(--text-secondary);
  margin-bottom: 0.25rem;
}

.project-list .project-meta {
  font-size: 0.8rem;
  color: var(--text-tertiary);
  font-family: 'JetBrains Mono', monospace;
}

/* ---------- Blog List ---------- */
.blog-list {
  list-style: none;
}

.blog-list li {
  padding: var(--spacing-md) 0;
  border-bottom: 1px solid var(--divider);
}

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

.blog-list .post-title {
  font-size: 1.05rem;
  font-weight: 400;
  color: var(--text-primary);
  margin-bottom: 0.25rem;
}

.blog-list .post-title a {
  color: var(--text-primary);
  border-bottom: none;
}

.blog-list .post-title a:hover {
  color: var(--accent);
}

.blog-list .post-meta {
  font-size: 0.8rem;
  color: var(--text-tertiary);
  font-family: 'JetBrains Mono', monospace;
}

.blog-list .post-excerpt {
  font-size: 0.9rem;
  color: var(--text-secondary);
  margin-top: 0.5rem;
}

/* ---------- Blog Post ---------- */
.post-header {
  margin-bottom: var(--spacing-xl);
  padding-bottom: var(--spacing-lg);
  border-bottom: 1px solid var(--divider);
}

.post-header h1 {
  font-size: 2rem;
  font-weight: 300;
  margin-bottom: var(--spacing-sm);
}

.post-header .post-meta {
  font-size: 0.85rem;
  color: var(--text-tertiary);
  font-family: 'JetBrains Mono', monospace;
}

.post-content {
  font-size: 1rem;
  line-height: 1.8;
  color: var(--text-secondary);
}

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

.post-content h2 {
  font-size: 1.4rem;
  margin-top: var(--spacing-xl);
  margin-bottom: var(--spacing-md);
  color: var(--text-primary);
}

.post-content h3 {
  font-size: 1.15rem;
  margin-top: var(--spacing-lg);
  margin-bottom: var(--spacing-sm);
  color: var(--text-primary);
}

.post-content code {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.85em;
  background-color: var(--bg-secondary);
  padding: 0.15em 0.4em;
  border: 1px solid var(--divider);
}

.post-content pre {
  background-color: var(--bg-secondary);
  border: 1px solid var(--divider);
  padding: var(--spacing-md);
  overflow-x: auto;
  margin-bottom: var(--spacing-md);
}

.post-content pre code {
  background: none;
  border: none;
  padding: 0;
}

.post-content blockquote {
  border-left: 2px solid var(--accent);
  padding-left: var(--spacing-md);
  margin: var(--spacing-md) 0;
  color: var(--text-tertiary);
  font-style: italic;
}

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

.post-content li {
  margin-bottom: 0.5rem;
}

/* ---------- About Page ---------- */
.about-section {
  margin-bottom: var(--spacing-xl);
}

.about-section h2 {
  font-size: 1.3rem;
  margin-bottom: var(--spacing-md);
  color: var(--text-primary);
}

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

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

.contact-list li {
  padding: var(--spacing-sm) 0;
  border-bottom: 1px solid var(--divider);
  font-size: 0.95rem;
}

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

.contact-list .label {
  font-size: 0.8rem;
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--text-tertiary);
  display: block;
  margin-bottom: 0.25rem;
}

/* ---------- Footer ---------- */
.site-footer {
  padding: var(--spacing-xl) 0;
  border-top: 1px solid var(--divider);
}

.site-footer .container {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.footer-links {
  display: flex;
  list-style: none;
  gap: var(--spacing-md);
}

.footer-links a {
  font-size: 0.85rem;
  color: var(--text-secondary);
  border-bottom: none;
}

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

.footer-copy {
  font-size: 0.8rem;
  color: var(--text-tertiary);
}

/* ---------- Responsive: Tablet ---------- */
@media (max-width: 768px) {
  :root {
    --spacing-xl: 3rem;
  }

  .hero h1 {
    font-size: 2rem;
  }

  .nav-links {
    gap: var(--spacing-sm);
  }

  .nav-links a {
    font-size: 0.8rem;
  }
}

/* ---------- Responsive: Mobile ---------- */
@media (max-width: 480px) {
  :root {
    --spacing-lg: 2rem;
    --spacing-xl: 2.5rem;
  }

  html {
    font-size: 15px;
  }

  .hero h1 {
    font-size: 1.75rem;
  }

  .hero .subtitle {
    font-size: 1rem;
  }

  .nav-links {
    gap: var(--spacing-xs);
  }

  .nav-links a {
    font-size: 0.75rem;
  }

  .site-footer .container {
    flex-direction: column;
    gap: var(--spacing-md);
    text-align: center;
  }

  .footer-links {
    flex-wrap: wrap;
    justify-content: center;
  }
}

/* ---------- Print ---------- */
@media print {
  .site-nav,
  .site-footer,
  .nav-theme-toggle {
    display: none;
  }

  .site-main {
    padding-top: 0;
  }

  body {
    color: #000;
    background: #fff;
  }
}