/* ============================================
   EdYou — Zachary Katz
   Editorial design, inspired by long-form essay sites
   ============================================ */

@import url('https://fonts.googleapis.com/css2?family=Newsreader:ital,opsz,wght@0,6..72,300;0,6..72,400;0,6..72,500;0,6..72,600;1,6..72,300;1,6..72,400;1,6..72,500&family=Source+Sans+3:ital,wght@0,300;0,400;0,500;0,600;1,400&display=swap');

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

:root {
  --color-bg: #FDFBF7;
  --color-text: #2C2C2C;
  --color-text-light: #6B6B6B;
  --color-accent: #B44A2F;
  --color-accent-hover: #943D27;
  --color-border: #E6E0D6;
  --color-sidebar-bg: #F6F3ED;
  --color-link: #2C2C2C;
  --font-serif: 'Newsreader', Georgia, serif;
  --font-sans: 'Source Sans 3', -apple-system, sans-serif;
  --content-width: 660px;
  --sidebar-width: 220px;
}

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

body {
  font-family: var(--font-sans);
  color: var(--color-text);
  background: var(--color-bg);
  line-height: 1.7;
  min-height: 100vh;
}

::selection {
  background: var(--color-accent);
  color: white;
}

a {
  color: var(--color-link);
  text-decoration-color: var(--color-border);
  text-underline-offset: 3px;
  transition: color 0.2s, text-decoration-color 0.2s;
}
a:hover {
  color: var(--color-accent);
  text-decoration-color: var(--color-accent);
}

/* --- Site Header --- */
.site-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  max-width: 1100px;
  margin: 0 auto;
  padding: 2rem 2rem 0;
}

.site-logo {
  font-family: var(--font-serif);
  font-size: 1.25rem;
  font-weight: 500;
  letter-spacing: -0.01em;
  color: var(--color-text);
  text-decoration: none;
}
.site-logo:hover {
  color: var(--color-accent);
}
.site-logo span {
  color: var(--color-accent);
}

.site-nav {
  display: flex;
  gap: 1.75rem;
}
.site-nav a {
  font-size: 0.9rem;
  font-weight: 400;
  color: var(--color-text-light);
  text-decoration: none;
  letter-spacing: 0.02em;
  transition: color 0.2s;
}
.site-nav a:hover,
.site-nav a.active {
  color: var(--color-text);
}

/* --- Page Hero (Homepage) --- */
.hero {
  max-width: var(--content-width);
  margin: 6rem auto 4rem;
  padding: 0 2rem;
}

.hero h1 {
  font-family: var(--font-serif);
  font-size: 2.8rem;
  font-weight: 400;
  line-height: 1.2;
  letter-spacing: -0.02em;
  margin-bottom: 1.5rem;
  color: var(--color-text);
}

.hero-subtitle {
  font-family: var(--font-serif);
  font-size: 1.3rem;
  font-weight: 300;
  font-style: italic;
  color: var(--color-text-light);
  line-height: 1.6;
  margin-bottom: 2rem;
}

.hero-body {
  font-size: 1.05rem;
  line-height: 1.8;
  color: var(--color-text);
}
.hero-body p {
  margin-bottom: 1.25rem;
}

.divider {
  width: 60px;
  height: 1px;
  background: var(--color-accent);
  margin: 3rem 0;
}

/* --- Contact Block --- */
.contact-block {
  font-size: 0.95rem;
  color: var(--color-text-light);
  line-height: 2;
}
.contact-block a {
  color: var(--color-accent);
  font-weight: 500;
}

/* --- Writing List --- */
.writing-list {
  max-width: var(--content-width);
  margin: 4rem auto;
  padding: 0 2rem;
}

.writing-list h2 {
  font-family: var(--font-serif);
  font-size: 1.8rem;
  font-weight: 400;
  margin-bottom: 2.5rem;
  letter-spacing: -0.01em;
}

.writing-item {
  display: block;
  text-decoration: none;
  padding: 1.5rem 0;
  border-top: 1px solid var(--color-border);
  transition: padding-left 0.2s;
}
.writing-item:last-child {
  border-bottom: 1px solid var(--color-border);
}
.writing-item:hover {
  padding-left: 0.5rem;
}

.writing-item-title {
  font-family: var(--font-serif);
  font-size: 1.3rem;
  font-weight: 500;
  color: var(--color-text);
  margin-bottom: 0.35rem;
  transition: color 0.2s;
}
.writing-item:hover .writing-item-title {
  color: var(--color-accent);
}

.writing-item-meta {
  font-size: 0.85rem;
  color: var(--color-text-light);
  letter-spacing: 0.02em;
}

.writing-item-desc {
  font-size: 0.95rem;
  color: var(--color-text-light);
  margin-top: 0.4rem;
  line-height: 1.6;
}

/* --- Essay Layout (Sidebar + Content) --- */
.essay-layout {
  display: grid;
  grid-template-columns: var(--sidebar-width) minmax(0, var(--content-width)) 1fr;
  gap: 3rem;
  max-width: 1100px;
  margin: 0 auto;
  padding: 3rem 2rem 6rem;
}

/* Sidebar TOC */
.essay-sidebar {
  position: relative;
}

.essay-toc {
  position: sticky;
  top: 2.5rem;
  padding-right: 1.5rem;
}

.essay-toc-title {
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--color-text-light);
  margin-bottom: 1rem;
}

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

.essay-toc li {
  margin-bottom: 0.6rem;
}

.essay-toc a {
  font-size: 0.82rem;
  color: var(--color-text-light);
  text-decoration: none;
  line-height: 1.45;
  display: block;
  padding-left: 0.75rem;
  border-left: 2px solid transparent;
  transition: color 0.2s, border-color 0.2s;
}
.essay-toc a:hover,
.essay-toc a.active {
  color: var(--color-text);
  border-left-color: var(--color-accent);
}

/* Essay Content */
.essay-header {
  margin-bottom: 3rem;
}

.essay-header h1 {
  font-family: var(--font-serif);
  font-size: 2.6rem;
  font-weight: 400;
  line-height: 1.2;
  letter-spacing: -0.02em;
  margin-bottom: 0.75rem;
}

.essay-header .essay-date {
  font-size: 0.9rem;
  color: var(--color-text-light);
  letter-spacing: 0.02em;
}

.essay-content h2 {
  font-family: var(--font-serif);
  font-size: 1.7rem;
  font-weight: 400;
  margin-top: 3rem;
  margin-bottom: 1rem;
  padding-top: 1rem;
  letter-spacing: -0.01em;
  color: var(--color-text);
}

.essay-content h3 {
  font-family: var(--font-serif);
  font-size: 1.25rem;
  font-weight: 500;
  margin-top: 2rem;
  margin-bottom: 0.75rem;
}

.essay-content p {
  margin-bottom: 1.25rem;
  line-height: 1.8;
}

.essay-content strong {
  font-weight: 600;
}

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

.essay-content blockquote {
  margin: 2rem 0;
  padding: 0.25rem 0 0.25rem 1.5rem;
  border-left: 3px solid var(--color-accent);
  font-family: var(--font-serif);
  font-style: italic;
  font-size: 1.1rem;
  color: var(--color-text-light);
  line-height: 1.7;
}

.essay-content ul,
.essay-content ol {
  margin: 1.25rem 0;
  padding-left: 1.5rem;
}
.essay-content li {
  margin-bottom: 0.5rem;
  line-height: 1.7;
}

.essay-content .formula {
  background: var(--color-sidebar-bg);
  border: 1px solid var(--color-border);
  border-radius: 6px;
  padding: 1.5rem 2rem;
  margin: 2rem 0;
  text-align: center;
  font-family: var(--font-serif);
  font-size: 1.3rem;
  letter-spacing: 0.02em;
  overflow-x: auto;
}

.essay-content .formula .formula-label {
  font-size: 0.8rem;
  font-family: var(--font-sans);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--color-text-light);
  margin-bottom: 0.75rem;
}

.essay-content .note {
  background: var(--color-sidebar-bg);
  border-left: 3px solid var(--color-accent);
  padding: 1.25rem 1.5rem;
  margin: 2rem 0;
  border-radius: 0 6px 6px 0;
  font-size: 0.95rem;
  line-height: 1.7;
}

.essay-content .variable-table {
  width: 100%;
  border-collapse: collapse;
  margin: 1.5rem 0;
}
.essay-content .variable-table th,
.essay-content .variable-table td {
  text-align: left;
  padding: 0.65rem 1rem;
  border-bottom: 1px solid var(--color-border);
  font-size: 0.95rem;
}
.essay-content .variable-table th {
  font-weight: 600;
  font-size: 0.8rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--color-text-light);
}
.essay-content .variable-table code {
  font-family: var(--font-serif);
  font-style: italic;
  font-size: 1.05rem;
  color: var(--color-accent);
  background: none;
}

/* --- Footer --- */
.site-footer {
  max-width: 1100px;
  margin: 0 auto;
  padding: 2.5rem 2rem;
  border-top: 1px solid var(--color-border);
  font-size: 0.8rem;
  color: var(--color-text-light);
  display: flex;
  justify-content: space-between;
}

/* --- Responsive --- */
@media (max-width: 900px) {
  .essay-layout {
    display: block;
    padding: 2rem 1.5rem 4rem;
  }
  .essay-sidebar {
    display: none;
  }
  .hero {
    margin: 3rem auto 2rem;
  }
  .hero h1 {
    font-size: 2rem;
  }
  .essay-header h1 {
    font-size: 2rem;
  }
  .site-header {
    padding: 1.5rem 1.5rem 0;
  }
}

@media (max-width: 600px) {
  html { font-size: 16px; }
  .hero h1 { font-size: 1.75rem; }
  .site-nav { gap: 1rem; }
  .hero { padding: 0 1.25rem; }
  .writing-list { padding: 0 1.25rem; }
  .hero > div[style*="display: flex"] {
    flex-direction: column-reverse !important;
    align-items: center !important;
    text-align: center;
  }
}

/* --- Fade-in animation --- */
@keyframes fadeUp {
  from { opacity: 0; transform: translateY(16px); }
  to { opacity: 1; transform: translateY(0); }
}

.fade-in {
  animation: fadeUp 0.6s ease-out both;
}
.fade-in-d1 { animation-delay: 0.1s; }
.fade-in-d2 { animation-delay: 0.2s; }
.fade-in-d3 { animation-delay: 0.3s; }