/* Counting the Atoms — Style Sheet */
/* Leopold-style: dark, serif, long-form reading */

@import url('https://fonts.googleapis.com/css2?family=Source+Serif+4:ital,opsz,wght@0,8..60,300;0,8..60,400;0,8..60,600;0,8..60,700;1,8..60,300;1,8..60,400&display=swap');

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

:root {
  --bg: #1a1a1a;
  --bg-surface: #222;
  --text: #e0ddd5;
  --text-muted: #a09d94;
  --text-dim: #6b6860;
  --accent: #c4a35a;
  --accent-hover: #d4b86a;
  --link: #c4a35a;
  --border: #333;
  --max-width: 680px;
}

html {
  font-size: 18px;
  scroll-behavior: smooth;
}

body {
  background: var(--bg);
  color: var(--text);
  font-family: 'Source Serif 4', 'Georgia', 'Times New Roman', serif;
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* Layout */
.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
}

/* Landing page */
.landing {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  justify-content: center;
  padding: 80px 24px;
}

.landing-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  width: 100%;
}

.landing h1 {
  font-size: 2.8rem;
  font-weight: 700;
  line-height: 1.15;
  letter-spacing: -0.02em;
  margin-bottom: 0.3em;
  color: #fff;
}

.landing .subtitle {
  font-size: 1.15rem;
  color: var(--text-muted);
  font-style: italic;
  margin-bottom: 2.5em;
  font-weight: 300;
}

.landing .intro {
  font-size: 1.05rem;
  line-height: 1.8;
  color: var(--text);
  margin-bottom: 3em;
  max-width: 600px;
}

.toc-landing {
  list-style: none;
  padding: 0;
  margin: 0;
}

.toc-landing li {
  margin-bottom: 1.8em;
}

.toc-landing a {
  text-decoration: none;
  color: #fff;
  font-size: 1.3rem;
  font-weight: 600;
  display: block;
  transition: color 0.15s;
}

.toc-landing a:hover {
  color: var(--accent);
}

.toc-landing .desc {
  font-size: 0.92rem;
  color: var(--text-muted);
  margin-top: 0.3em;
  line-height: 1.6;
  font-weight: 300;
}

/* Essay pages */
.essay-header {
  padding: 100px 0 40px;
  border-bottom: 1px solid var(--border);
  margin-bottom: 40px;
}

.essay-header .series {
  font-size: 0.85rem;
  color: var(--accent);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin-bottom: 0.8em;
  font-weight: 600;
}

.essay-header .series a {
  color: var(--accent);
  text-decoration: none;
}

.essay-header .series a:hover {
  text-decoration: underline;
}

.essay-header h1 {
  font-size: 2.4rem;
  font-weight: 700;
  line-height: 1.15;
  letter-spacing: -0.02em;
  color: #fff;
  margin-bottom: 0.4em;
}

.essay-header .meta {
  font-size: 0.9rem;
  color: var(--text-muted);
  font-style: italic;
}

/* Table of contents */
.essay-toc {
  margin-bottom: 3em;
  padding: 1.5em 0;
  border-bottom: 1px solid var(--border);
}

.essay-toc h2 {
  font-size: 0.85rem;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--text-dim);
  margin-bottom: 1em;
  font-weight: 600;
}

.essay-toc ol {
  list-style: none;
  padding: 0;
  counter-reset: toc;
}

.essay-toc li {
  counter-increment: toc;
  margin-bottom: 0.5em;
}

.essay-toc li::before {
  content: counter(toc, upper-roman) ". ";
  color: var(--text-dim);
  font-size: 0.85rem;
}

.essay-toc a {
  color: var(--text-muted);
  text-decoration: none;
  font-size: 0.95rem;
  transition: color 0.15s;
}

.essay-toc a:hover {
  color: var(--accent);
}

/* Essay body */
.essay-body h2 {
  font-size: 1.5rem;
  font-weight: 700;
  color: #fff;
  margin: 2.5em 0 0.8em;
  line-height: 1.3;
}

.essay-body p {
  margin-bottom: 1.3em;
}

.essay-body strong {
  color: #fff;
  font-weight: 600;
}

.essay-body em {
  font-style: italic;
}

.essay-body blockquote {
  border-left: 3px solid var(--accent);
  padding-left: 1.2em;
  margin: 1.5em 0;
  color: var(--text-muted);
  font-style: italic;
}

.essay-body a {
  color: var(--link);
  text-decoration: underline;
  text-decoration-color: rgba(196, 163, 90, 0.3);
  text-underline-offset: 3px;
  transition: text-decoration-color 0.15s;
}

.essay-body a:hover {
  text-decoration-color: var(--accent);
}

.essay-body ul, .essay-body ol {
  margin: 1em 0 1.3em 1.5em;
}

.essay-body li {
  margin-bottom: 0.4em;
}

/* Horizontal rules */
.essay-body hr {
  border: none;
  border-top: 1px solid var(--border);
  margin: 3em 0;
}

/* Pull quote / emphasis block */
.pull-quote {
  font-size: 1.2rem;
  line-height: 1.6;
  color: var(--accent);
  font-style: italic;
  margin: 2em 0;
  padding: 0.5em 0;
}

/* Data callout */
.data-callout {
  background: var(--bg-surface);
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: 1.2em 1.5em;
  margin: 1.5em 0;
  font-size: 0.92rem;
}

.data-callout p {
  margin-bottom: 0.6em;
}

.data-callout p:last-child {
  margin-bottom: 0;
}

/* Sources */
.sources {
  margin-top: 3em;
  padding-top: 2em;
  border-top: 1px solid var(--border);
}

.sources h2 {
  font-size: 1rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-dim);
  margin-bottom: 1em;
  font-weight: 600;
}

.sources ul {
  list-style: none;
  padding: 0;
}

.sources li {
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-bottom: 0.5em;
  line-height: 1.5;
}

/* Author bio */
.author-bio {
  margin-top: 3em;
  padding: 2em 0;
  border-top: 1px solid var(--border);
  font-size: 0.9rem;
  color: var(--text-muted);
  font-style: italic;
  line-height: 1.7;
}

/* Navigation between parts */
.essay-nav {
  margin-top: 3em;
  padding: 2em 0;
  border-top: 1px solid var(--border);
  display: flex;
  justify-content: space-between;
  gap: 1em;
}

.essay-nav a {
  color: var(--accent);
  text-decoration: none;
  font-size: 0.95rem;
  font-weight: 600;
  transition: color 0.15s;
}

.essay-nav a:hover {
  color: var(--accent-hover);
}

/* Footer */
.site-footer {
  padding: 3em 0 4em;
  text-align: center;
  font-size: 0.8rem;
  color: var(--text-dim);
}

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

  .landing {
    padding: 60px 20px;
  }

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

  .toc-landing a {
    font-size: 1.15rem;
  }

  .essay-header {
    padding: 60px 0 30px;
  }

  .essay-header h1 {
    font-size: 1.8rem;
  }

  .container {
    padding: 0 20px;
  }

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