/* ===== CSS Variables / Theming ===== */
:root {
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-serif: 'Newsreader', Georgia, 'Times New Roman', serif;

  --color-bg: #fafaf9;
  --color-bg-alt: #f5f5f4;
  --color-text: #1c1917;
  --color-text-secondary: #78716c;
  --color-accent: #b45309;
  --color-accent-hover: #92400e;
  --color-border: #e7e5e4;
  --color-link: #b45309;
  --color-link-hover: #92400e;
  --color-code-bg: #f5f5f4;
  --color-tag-bg: #fef3c7;
  --color-tag-text: #92400e;

  --max-width: 680px;
  --header-height: 64px;
  --spacing-unit: 8px;
}

[data-theme="dark"] {
  --color-bg: #1a1a1a;
  --color-bg-alt: #262626;
  --color-text: #e7e5e4;
  --color-text-secondary: #a8a29e;
  --color-accent: #f59e0b;
  --color-accent-hover: #fbbf24;
  --color-border: #3a3a3a;
  --color-link: #f59e0b;
  --color-link-hover: #fbbf24;
  --color-code-bg: #262626;
  --color-tag-bg: #422006;
  --color-tag-text: #fbbf24;
}

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

html {
  font-size: 18px;
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-sans);
  color: var(--color-text);
  background-color: var(--color-bg);
  line-height: 1.7;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  transition: background-color 0.3s ease, color 0.3s ease;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 calc(var(--spacing-unit) * 3);
}

a {
  color: var(--color-link);
  text-decoration: none;
  transition: color 0.2s ease;
}

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

img {
  max-width: 100%;
  height: auto;
  border-radius: 6px;
}

/* ===== Header ===== */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: var(--color-bg);
  border-bottom: 1px solid var(--color-border);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
}

.site-header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: var(--header-height);
}

.site-title {
  font-weight: 700;
  font-size: 1.15rem;
  color: var(--color-text);
  letter-spacing: -0.02em;
}

.site-title:hover {
  color: var(--color-accent);
}

.site-nav {
  display: flex;
  align-items: center;
  gap: calc(var(--spacing-unit) * 3);
}

.site-nav a {
  font-size: 0.88rem;
  font-weight: 500;
  color: var(--color-text-secondary);
  letter-spacing: 0.01em;
}

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

/* ===== Theme Toggle ===== */
.theme-toggle {
  background: none;
  border: none;
  cursor: pointer;
  color: var(--color-text-secondary);
  padding: 4px;
  display: flex;
  align-items: center;
  transition: color 0.2s;
  border-radius: 6px;
}

.theme-toggle:hover {
  color: var(--color-text);
  background: var(--color-bg-alt);
}

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

/* ===== Hero ===== */
.hero {
  padding: calc(var(--spacing-unit) * 8) 0 calc(var(--spacing-unit) * 6);
}

.hero h1 {
  font-family: var(--font-serif);
  font-size: 2rem;
  font-weight: 400;
  line-height: 1.35;
  color: var(--color-text);
  font-style: italic;
  letter-spacing: -0.01em;
}

/* ===== Posts List ===== */
.section-title {
  font-family: var(--font-serif);
  font-size: 1.8rem;
  font-weight: 500;
  margin: calc(var(--spacing-unit) * 6) 0 calc(var(--spacing-unit) * 4);
  letter-spacing: -0.02em;
}

.posts-list {
  padding-bottom: calc(var(--spacing-unit) * 8);
}

.post-preview {
  padding: calc(var(--spacing-unit) * 4) 0;
  border-bottom: 1px solid var(--color-border);
}

.post-preview:first-child {
  border-top: none;
}

.post-preview time {
  font-size: 0.8rem;
  color: var(--color-text-secondary);
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.post-preview h2 {
  font-family: var(--font-serif);
  font-size: 1.45rem;
  font-weight: 500;
  margin: calc(var(--spacing-unit) * 0.75) 0;
  letter-spacing: -0.02em;
  line-height: 1.3;
}

.post-preview h2 a {
  color: var(--color-text);
}

.post-preview h2 a:hover {
  color: var(--color-accent);
}

.post-preview .subtitle {
  font-family: var(--font-serif);
  font-style: italic;
  color: var(--color-text-secondary);
  margin-bottom: calc(var(--spacing-unit) * 1);
  font-size: 1.05rem;
}

.post-preview .excerpt {
  color: var(--color-text-secondary);
  font-size: 0.92rem;
  line-height: 1.65;
  margin-bottom: calc(var(--spacing-unit) * 1.5);
}

.read-more {
  font-size: 0.85rem;
  font-weight: 600;
  letter-spacing: 0.01em;
}

/* ===== Single Post ===== */
.post {
  padding-bottom: calc(var(--spacing-unit) * 10);
}

.post-header {
  padding: calc(var(--spacing-unit) * 6) 0 calc(var(--spacing-unit) * 4);
  border-bottom: 1px solid var(--color-border);
  margin-bottom: calc(var(--spacing-unit) * 5);
}

.post-header time {
  font-size: 0.8rem;
  color: var(--color-text-secondary);
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.post-header h1 {
  font-family: var(--font-serif);
  font-size: 2.2rem;
  font-weight: 500;
  margin: calc(var(--spacing-unit) * 1.5) 0;
  letter-spacing: -0.025em;
  line-height: 1.2;
}

.post-header .subtitle {
  font-family: var(--font-serif);
  font-style: italic;
  color: var(--color-text-secondary);
  font-size: 1.15rem;
  line-height: 1.5;
}

.tags {
  display: flex;
  gap: calc(var(--spacing-unit) * 1);
  flex-wrap: wrap;
  margin-top: calc(var(--spacing-unit) * 2);
}

.tag {
  font-size: 0.75rem;
  font-weight: 600;
  padding: 2px 10px;
  border-radius: 100px;
  background: var(--color-tag-bg);
  color: var(--color-tag-text);
  letter-spacing: 0.02em;
}

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

/* ===== Post Content (Prose) ===== */
.post-content {
  font-family: var(--font-serif);
  font-size: 1.05rem;
  line-height: 1.8;
}

.post-content p {
  margin-bottom: 1.5em;
}

.post-content h2 {
  font-family: var(--font-sans);
  font-size: 1.35rem;
  font-weight: 600;
  margin: 2.5em 0 0.8em;
  letter-spacing: -0.02em;
}

.post-content h3 {
  font-family: var(--font-sans);
  font-size: 1.1rem;
  font-weight: 600;
  margin: 2em 0 0.6em;
}

.post-content a {
  text-decoration: underline;
  text-underline-offset: 2px;
}

.post-content blockquote {
  border-left: 3px solid var(--color-accent);
  padding-left: calc(var(--spacing-unit) * 3);
  margin: 2em 0;
  font-style: italic;
  color: var(--color-text-secondary);
}

.post-content ul, .post-content ol {
  padding-left: 1.5em;
  margin-bottom: 1.5em;
}

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

.post-content code {
  font-size: 0.88em;
  background: var(--color-code-bg);
  padding: 2px 6px;
  border-radius: 4px;
}

.post-content pre {
  background: var(--color-code-bg);
  padding: calc(var(--spacing-unit) * 2.5);
  border-radius: 8px;
  overflow-x: auto;
  margin: 2em 0;
  font-size: 0.85rem;
  line-height: 1.6;
}

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

.post-content hr {
  border: none;
  height: 1px;
  background: var(--color-border);
  margin: 3em 0;
}

.post-content figure {
  margin: 2em 0;
}

.post-content figcaption {
  font-family: var(--font-sans);
  font-size: 0.82rem;
  color: var(--color-text-secondary);
  text-align: center;
  margin-top: calc(var(--spacing-unit) * 1);
}

/* ===== Post Footer Nav ===== */
.post-footer {
  margin-top: calc(var(--spacing-unit) * 6);
  padding-top: calc(var(--spacing-unit) * 4);
  border-top: 1px solid var(--color-border);
}

.post-nav {
  display: flex;
  justify-content: space-between;
  gap: calc(var(--spacing-unit) * 3);
}

.prev-post, .next-post {
  font-size: 0.9rem;
  font-weight: 500;
  max-width: 48%;
}

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

/* ===== About Page ===== */
.page-content {
  padding: calc(var(--spacing-unit) * 6) 0 calc(var(--spacing-unit) * 10);
}

.page-content h1 {
  font-family: var(--font-serif);
  font-size: 2rem;
  font-weight: 500;
  margin-bottom: calc(var(--spacing-unit) * 4);
  letter-spacing: -0.02em;
}

.page-content .content {
  font-family: var(--font-serif);
  font-size: 1.05rem;
  line-height: 1.8;
}

.page-content .content p {
  margin-bottom: 1.5em;
}

.page-content .content a {
  text-decoration: underline;
  text-underline-offset: 2px;
}

/* ===== Pagination ===== */
.pagination {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: calc(var(--spacing-unit) * 3);
  padding: calc(var(--spacing-unit) * 5) 0;
  font-size: 0.9rem;
}

.page-number {
  color: var(--color-text-secondary);
}

/* ===== Footer ===== */
.site-footer {
  margin-top: auto;
  border-top: 1px solid var(--color-border);
  padding: calc(var(--spacing-unit) * 4) 0;
}

.site-footer p {
  font-size: 0.82rem;
  color: var(--color-text-secondary);
  text-align: center;
}

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

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

/* ===== Responsive ===== */
@media (max-width: 640px) {
  html {
    font-size: 16px;
  }

  .hero {
    padding: calc(var(--spacing-unit) * 5) 0 calc(var(--spacing-unit) * 4);
  }

  .hero h1 {
    font-size: 1.6rem;
  }

  .post-header h1 {
    font-size: 1.7rem;
  }

  .post-nav {
    flex-direction: column;
  }

  .prev-post, .next-post {
    max-width: 100%;
    text-align: left;
    margin-left: 0;
  }
}

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

  body {
    font-size: 12pt;
    color: #000;
    background: #fff;
  }
}