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

:root {
  --font-heading: "DM Serif Display", Georgia, serif;
  --font-body: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  --max-width: 1100px;
  --max-width-narrow: 720px;
}

/* ============================================
   Light theme (default)
   ============================================ */
[data-theme="light"] {
  --color-bg: #ffffff;
  --color-bg-alt: #f5f5f5;
  --color-text: #3a3a3a;
  --color-text-secondary: #6b6b6b;
  --color-text-heading: #1a1a1a;
  --color-border: #e0e0e0;
  --color-link: #3a3a3a;
  --color-link-hover: #000000;
  --color-placeholder-bg: #eaeaea;
  --color-placeholder-text: #999999;
  --color-header-bg: rgba(255, 255, 255, 0.92);
}

/* ============================================
   Dark theme
   ============================================ */
[data-theme="dark"] {
  --color-bg: #1a1a1a;
  --color-bg-alt: #222222;
  --color-text: #d0d0d0;
  --color-text-secondary: #909090;
  --color-text-heading: #ffffff;
  --color-border: #333333;
  --color-link: #c0c0c0;
  --color-link-hover: #ffffff;
  --color-placeholder-bg: #2a2a2a;
  --color-placeholder-text: #555555;
  --color-header-bg: rgba(26, 26, 26, 0.92);
}

html {
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: var(--font-body);
  color: var(--color-text);
  background: var(--color-bg);
  line-height: 1.75;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  transition: background 0.3s, color 0.3s;
}

main {
  flex: 1;
}

a {
  color: var(--color-link);
  text-decoration: underline;
  text-underline-offset: 2px;
  transition: color 0.2s;
}

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

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

h1, h2, h3, h4 {
  font-family: var(--font-heading);
  line-height: 1.3;
  font-weight: 400;
  color: var(--color-text-heading);
}

h1 {
  font-size: 2.5rem;
  letter-spacing: -0.01em;
}

h2 {
  font-size: 1.6rem;
}

h3 {
  font-size: 1.2rem;
}

/* ============================================
   Layout
   ============================================ */
.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 2rem;
}

.container-narrow {
  max-width: var(--max-width-narrow);
  margin: 0 auto;
  padding: 0 2rem;
}

/* ============================================
   Navigation
   ============================================ */
.site-header {
  border-bottom: 1px solid var(--color-border);
  background: var(--color-header-bg);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  transition: background 0.3s, border-color 0.3s;
}

.nav-container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 2rem;
  height: 56px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-logo {
  font-family: var(--font-heading);
  font-size: 1.1rem;
  font-weight: 400;
  color: var(--color-text-heading);
  text-decoration: none;
}

.nav-logo:hover {
  color: var(--color-text-heading);
}

.nav-links {
  list-style: none;
  display: flex;
  align-items: center;
  gap: 1.75rem;
}

.nav-links a {
  color: var(--color-text-secondary);
  font-size: 0.8rem;
  font-weight: 500;
  text-decoration: none;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  transition: color 0.2s;
}

.nav-links a:hover,
.nav-links a.active {
  color: var(--color-text-heading);
}

.nav-check {
  display: none;
}

.nav-toggle {
  display: none;
  cursor: pointer;
  padding: 0.5rem;
  flex-direction: column;
  gap: 5px;
}

.nav-toggle span {
  display: block;
  width: 20px;
  height: 2px;
  background: var(--color-text);
  border-radius: 1px;
}

/* ============================================
   Theme Toggle
   ============================================ */
.theme-toggle {
  background: none;
  border: 1px solid var(--color-border);
  border-radius: 6px;
  cursor: pointer;
  padding: 5px 6px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-text-secondary);
  transition: color 0.2s, border-color 0.2s;
}

.theme-toggle:hover {
  color: var(--color-text-heading);
  border-color: var(--color-text-secondary);
}

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

/* ============================================
   Hero (Homepage)
   ============================================ */
.hero {
  padding: 4rem 0 5rem;
}

.hero-container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 2rem;
  display: flex;
  align-items: flex-start;
  gap: 4rem;
}

.hero-image {
  flex-shrink: 0;
}

.hero-image-placeholder {
  width: 280px;
  height: 350px;
  background: var(--color-placeholder-bg);
  border: 1px solid var(--color-border);
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-heading);
  font-size: 3rem;
  font-weight: 400;
  color: var(--color-placeholder-text);
  user-select: none;
  transition: background 0.3s, border-color 0.3s;
}

.hero-content {
  flex: 1;
  padding-top: 0.5rem;
}

.hero-content h1 {
  font-size: 2.75rem;
  margin-bottom: 1.5rem;
}

.hero-content > p {
  color: var(--color-text);
  font-size: 1rem;
  line-height: 1.8;
  margin-bottom: 1rem;
}

.hero-socials {
  margin-top: 1.5rem;
  font-size: 0.9rem;
}

.hero-socials a {
  color: var(--color-text-secondary);
  text-decoration: underline;
  text-underline-offset: 3px;
}

.hero-socials a:hover {
  color: var(--color-text-heading);
}

.hero-socials .sep {
  color: var(--color-text-secondary);
  margin: 0 0.4rem;
}

/* ============================================
   Sections
   ============================================ */
.section {
  padding: 4rem 0;
}

.section-alt {
  background: var(--color-bg-alt);
  transition: background 0.3s;
}

.section-title {
  margin-bottom: 2rem;
}

/* ============================================
   Post List
   ============================================ */
.post-list {
  display: flex;
  flex-direction: column;
  gap: 0;
}

.post-item {
  display: block;
  padding: 1.25rem 0;
  border-bottom: 1px solid var(--color-border);
  color: var(--color-text);
  text-decoration: none;
  transition: opacity 0.2s;
}

.post-item:first-child {
  border-top: 1px solid var(--color-border);
}

.post-item:hover {
  color: var(--color-text);
  opacity: 0.8;
}

.post-item time {
  font-family: var(--font-body);
  font-size: 0.8rem;
  color: var(--color-text-secondary);
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

.post-item h3 {
  margin: 0.3rem 0 0.35rem;
  font-size: 1.15rem;
}

.post-item p {
  color: var(--color-text-secondary);
  font-size: 0.9rem;
  line-height: 1.6;
}

/* ============================================
   Prose (single page content)
   ============================================ */
.container-narrow h1 {
  margin-bottom: 2rem;
}

.post-subtitle {
  font-size: 0.9rem;
  color: var(--color-text-secondary);
  margin-top: -1.25rem;
  margin-bottom: 2rem;
  font-style: italic;
}

.container-narrow h2 {
  margin-top: 2.5rem;
  margin-bottom: 1rem;
}

.container-narrow h3 {
  margin-top: 2rem;
  margin-bottom: 0.75rem;
}

.container-narrow p {
  margin-bottom: 1rem;
  color: var(--color-text);
}

.container-narrow ul,
.container-narrow ol {
  margin-bottom: 1rem;
  padding-left: 1.5rem;
}

.container-narrow li {
  margin-bottom: 0.4rem;
  color: var(--color-text);
}

.container-narrow strong {
  color: var(--color-text-heading);
}

.container-narrow hr {
  border: none;
  border-top: 1px solid var(--color-border);
  margin: 2.5rem 0;
}

.container-narrow code {
  font-size: 0.9em;
  padding: 0.15em 0.4em;
  background: var(--color-bg-alt);
  border-radius: 4px;
}

.container-narrow pre {
  margin: 0 0 1rem;
  padding: 1rem;
  overflow-x: auto;
  background: var(--color-bg-alt);
  border-radius: 6px;
  line-height: 1.5;
}

.container-narrow pre code {
  display: block;
  padding: 0;
  background: transparent;
  border-radius: 0;
  font-size: 0.85em;
}

.footnotes {
  margin-top: 3rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--color-border);
  font-size: 0.85rem;
}

.footnotes ol {
  padding-left: 1.5rem;
}

.footnotes li {
  margin-bottom: 0.75rem;
  color: var(--color-text-secondary);
}

.footnote-ref {
  font-size: 0.75em;
  vertical-align: super;
  text-decoration: none;
}

.footnote-backref {
  text-decoration: none;
  margin-left: 0.25rem;
}

/* ============================================
   Footer
   ============================================ */
.site-footer {
  border-top: 1px solid var(--color-border);
  padding: 2rem 0;
  background: var(--color-bg);
  transition: background 0.3s, border-color 0.3s;
}

.footer-container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 2rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.footer-socials {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.85rem;
}

.footer-socials a {
  color: var(--color-text-secondary);
  text-decoration: underline;
  text-underline-offset: 3px;
}

.footer-socials a:hover {
  color: var(--color-text-heading);
}

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

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

/* ============================================
   Mobile
   ============================================ */
@media (max-width: 768px) {
  .nav-toggle {
    display: flex;
  }

  .nav-links {
    display: none;
    position: absolute;
    top: 56px;
    left: 0;
    right: 0;
    background: var(--color-bg);
    flex-direction: column;
    padding: 1rem 2rem 1.5rem;
    gap: 0;
    border-bottom: 1px solid var(--color-border);
    z-index: 99;
  }

  .nav-check:checked ~ .nav-links {
    display: flex;
  }

  .nav-links li {
    border-bottom: 1px solid var(--color-border);
  }

  .nav-links li:last-child {
    border-bottom: none;
  }

  .nav-links a {
    display: block;
    padding: 0.75rem 0;
    font-size: 0.9rem;
  }

  .theme-toggle {
    margin-top: 0.5rem;
  }

  .hero {
    padding: 2.5rem 0 3rem;
  }

  .hero-container {
    flex-direction: column;
    gap: 2rem;
  }

  .hero-image-placeholder {
    width: 200px;
    height: 250px;
    font-size: 2.5rem;
  }

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

  .section {
    padding: 3rem 0;
  }

  .footer-container {
    flex-direction: column;
    gap: 0.75rem;
    text-align: center;
  }

  h1 {
    font-size: 1.75rem;
  }

  h2 {
    font-size: 1.35rem;
  }
}