/* Base design tokens */
:root {
  /* Dark mode tokens only */
  --bg: #000000;
  --fg: #e2e2e2;
  --muted: #888888;
  --border: #333333;
  --accent: #ffffff; /* Stark white accent for high contrast */
  --accent-hover: #cccccc;
  --code-bg: #111111;
  --shadow: none;
  --font-ui: "Libre Franklin", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  --font-serif: "Newsreader", Georgia, Cambria, serif;
  color-scheme: dark;
}

/* Global */
html { -webkit-text-size-adjust: 100%; }
body {
  font-family: var(--font-serif); /* Default to serif for reading experience */
  font-size: 20px;
  line-height: 1.6;
  color: var(--fg);
  background: var(--bg);
  margin: 0;
  padding: 0;
  text-rendering: optimizeLegibility;
}

.container {
  max-width: 880px;
  margin: 0 auto;
  padding: 0 24px;
}

/* Header Masthead */
.site-header {
  border-bottom: 1px solid var(--border);
  background: var(--bg);
  padding: 12px 0;
  position: sticky;
  top: 0;
  z-index: 1000;
}
.header-inner {
  position: relative;
  display: flex;
  justify-content: center;
  align-items: center;
  padding: 12px 0;
}
.branding {
  text-align: center;
}
.branding .site-title {
  color: var(--fg);
  font-family: var(--font-serif);
  font-weight: 800;
  letter-spacing: -0.01em;
  text-decoration: none;
  font-size: 1.6rem;
}

.hamburger { 
  position: absolute;
  left: 20px;
  display: inline-flex; 
  flex-direction: column; 
  gap: 4px; 
  background: transparent; 
  border: 0; 
  cursor: pointer; 
  padding: 8px;
}
.hamburger span { display: block; width: 20px; height: 1.5px; background: var(--fg); }

/* Breadcrumb / Editorial Meta */
.breadcrumb {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 24px;
  font-family: var(--font-ui);
  font-size: 0.7rem;
  font-weight: 900;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  color: var(--muted);
}
.breadcrumb .sep { color: var(--border); }
.breadcrumb .progress {
  flex: 1;
  position: relative;
  height: 2px;
  background: var(--border);
  margin-left: 12px;
}
.breadcrumb .progress .bar {
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  background: var(--fg);
}

/* Content Panel */
.content-panel {
  border-top: 4px solid var(--fg); /* Editorial accent */
  padding: 32px 0;
  margin-bottom: 40px;
}

h1, h2, h3 {
  font-family: var(--font-serif);
  line-height: 1.15;
  color: var(--fg);
  font-weight: 800;
  margin-bottom: 1rem;
}
h1 { font-size: clamp(2.2rem, 5vw + 1rem, 2.8rem); letter-spacing: -0.03em; }
h2 { font-size: 1.6rem; margin: 2.5rem 0 1rem; border-top: 1px solid var(--border); padding-top: 1.5rem; }

p { margin: 1.2rem 0; }
ul, ol { padding-left: 1.5rem; margin: 1.2rem 0; }
li { margin: 0.6rem 0; }

blockquote {
  margin: 2rem 0;
  padding: 1rem 1.5rem;
  border-left: 3px solid var(--fg);
  background: rgba(255, 255, 255, 0.03);
  font-style: italic;
  color: var(--muted);
}

/* Sidebar / Minimalist Index */
.drawer {
  position: fixed;
  top: 0;
  left: 0;
  bottom: 0;
  width: 86vw;
  max-width: 340px;
  background: var(--bg);
  border-right: 1px solid var(--border);
  transform: translateX(-100%);
  transition: transform 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  z-index: 1000;
  overflow: auto;
}
.drawer.open {
  transform: translateX(0);
}
.drawer-header {
  padding: 24px 20px;
  border-bottom: 1px solid var(--border);
  display: flex;
  justify-content: space-between;
  align-items: center;
}
.drawer-title {
  font-family: var(--font-ui);
  text-transform: uppercase;
  letter-spacing: 0.15em;
  font-weight: 900;
  font-size: 0.8rem;
}
.drawer-body {
  padding: 0 20px 40px;
  font-family: var(--font-ui);
}
.drawer-body h3 {
  margin: 32px 0 12px;
  font-size: 0.7rem;
  color: var(--muted);
  text-transform: uppercase;
  letter-spacing: 0.2em;
  font-weight: 900;
  border-top: 1px solid var(--border);
  padding-top: 16px;
}
.toc-list {
  list-style: none;
  padding: 0;
  margin: 0;
}
.toc-item {
  border-bottom: 1px solid rgba(255,255,255,0.05);
}
.toc-item a {
  display: block;
  padding: 14px 0;
  color: var(--fg);
  text-decoration: none !important;
  font-size: 1rem;
  line-height: 1.4;
  font-family: var(--font-serif);
}
.toc-item.active a {
  font-weight: 800;
  color: var(--accent);
}

.backdrop { position: fixed; inset: 0; background: rgba(0,0,0,0.6); z-index: 900; }

@media (max-width: 640px) {
  .container { padding: 0 20px; }
  .content { padding-top: 32px; }
  .content-panel { padding: 24px 0; }
  .branding .site-title { font-size: 1.4rem; }
}

/* Desktop Sidebar Layout */
@media (min-width: 1024px) {
  body { padding-left: 340px; }
  .drawer { transform: translateX(0); width: 340px; box-shadow: none; }
  .drawer-close, .hamburger { display: none; }
  .container { max-width: 760px; }
}

/* CTA & Buttons */
.cta-container {
  margin-top: 48px;
}
.btn-primary {
  display: inline-block;
  background: var(--fg);
  color: var(--bg) !important;
  padding: 18px 32px;
  font-family: var(--font-ui);
  font-weight: 800;
  text-transform: uppercase;
  letter-spacing: 0.15em;
  text-decoration: none !important;
  font-size: 0.9rem;
  transition: opacity 0.2s;
}
.btn-primary:hover {
  opacity: 0.9;
}

/* Post Navigation */
.post-nav {
  display: flex;
  justify-content: space-between;
  gap: 16px;
  margin-top: 64px;
  font-family: var(--font-ui);
}
.nav-link {
  flex: 1;
  display: flex;
  flex-direction: column;
  padding: 24px;
  border: 1px solid var(--border);
  text-decoration: none !important;
  transition: all 0.2s ease;
  background: transparent;
}
.nav-link.next {
  border: 2px solid var(--fg); /* Bolder border for primary action */
  text-align: right;
  align-items: flex-end;
}
.nav-link.next .nav-label { color: var(--muted); }
.nav-link.next .nav-title { color: var(--fg); }

.nav-link:hover {
  border-color: var(--fg);
  background: rgba(255, 255, 255, 0.05);
}

.nav-label {
  font-size: 0.7rem;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  color: var(--muted);
  margin-bottom: 8px;
  font-weight: 700;
}
.nav-title {
  font-family: var(--font-serif);
  font-size: 1.2rem;
  font-weight: 800;
  color: var(--fg);
  line-height: 1.2;
}
.nav-spacer {
  flex: 1;
}

@media (max-width: 640px) {
  .post-nav {
    flex-direction: column;
  }
  .nav-link.next {
    text-align: left;
    align-items: flex-start;
  }
  .btn-primary {
    display: block;
    text-align: center;
  }
}

/* Tables */
table { border-collapse: collapse; width: 100%; margin: 1.2rem 0; }
th, td { border: 1px solid var(--border); padding: 0.55rem 0.6rem; }
th { background: rgba(127,127,127,0.08); text-align: left; }

/* Images */
img {
  max-width: 100%;
  height: auto;
  display: block;
  margin: 2rem auto;
  cursor: zoom-in;
}

/* Lightbox */
.lightbox {
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.95);
  z-index: 2000;
  display: none;
  align-items: center;
  justify-content: center;
  padding: 20px;
}
.lightbox.open { display: flex; }
.lightbox img {
  max-width: 95vw;
  max-height: 90vh;
  margin: 0;
  cursor: zoom-out;
  object-fit: contain;
}
.lightbox-close {
  position: absolute;
  top: 20px;
  right: 20px;
  background: transparent;
  border: 0;
  color: #fff;
  font-size: 32px;
  cursor: pointer;
  z-index: 2100;
}

/* Footer */
.site-footer {
  border-top: 1px solid var(--border);
  padding: 24px 0 40px;
}
.footer-inner { display: flex; flex-wrap: wrap; gap: 12px 24px; align-items: center; }
.site-footer p { margin: 0; }
.copyright {
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  font-size: 0.8rem;
  color: var(--fg);
}
.muted { color: var(--muted); }

/* Install & Share buttons */
.install-button, .share-page-btn {
  appearance: none;
  border: 1px solid var(--border);
  background: var(--bg);
  color: var(--fg);
  padding: 8px;
  margin-left: 12px;
  box-shadow: var(--shadow);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 4px;
}
.install-button:hover, .share-page-btn:hover { border-color: var(--accent); color: var(--accent); }

/* Heading Share Anchors */
h1, h2, h3 { position: relative; }
.heading-share {
  background: none;
  border: 0;
  color: var(--muted);
  font-family: var(--font-serif);
  font-size: 0.8em;
  padding: 0 10px;
  cursor: pointer;
  opacity: 0;
  transition: opacity 0.2s;
  vertical-align: middle;
}
h1:hover .heading-share, h2:hover .heading-share, h3:hover .heading-share {
  opacity: 1;
}
.heading-share:hover { color: var(--fg); }

@media (max-width: 640px) {
  .heading-share { opacity: 0.4; } /* Always show slightly on mobile */
  .share-page-btn { margin-left: 0; margin-right: 12px; }
}

.install-hint {
  position: fixed; left: 16px; right: 16px; bottom: 16px;
  background: var(--bg); color: var(--fg);
  border: 1px solid var(--border);
  padding: 10px 12px;
  box-shadow: var(--shadow);
  font-size: 0.95rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  z-index: 3000;
}

/* Download Overlay */
.download-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.8);
  backdrop-filter: blur(4px);
  z-index: 4000;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 20px;
  animation: fadeIn 0.4s ease;
}
.download-overlay.fade-out {
  opacity: 0;
  transition: opacity 0.5s;
}
.overlay-content {
  background: var(--bg);
  border: 1px solid var(--border);
  padding: 40px 30px;
  max-width: 400px;
  width: 100%;
  position: relative;
  text-align: center;
}
.overlay-content h2 { margin-top: 0; }
.overlay-content p { color: var(--muted); margin-bottom: 24px; }
.overlay-close {
  position: absolute;
  top: 10px;
  right: 15px;
  background: none;
  border: 0;
  color: var(--muted);
  font-size: 28px;
  cursor: pointer;
}
.overlay-dismiss-btn, .overlay-install-btn { width: 100%; margin-bottom: 12px; }
.overlay-dismiss-link {
  background: none;
  border: 0;
  color: var(--muted);
  font-family: var(--font-ui);
  text-transform: uppercase;
  font-size: 0.7rem;
  letter-spacing: 0.1em;
  cursor: pointer;
  margin-top: 8px;
}
.ios-instructions {
  background: rgba(255,255,255,0.05);
  padding: 16px;
  border-radius: 8px;
  font-size: 0.9rem;
  margin-bottom: 24px;
  line-height: 1.4;
}

@keyframes fadeIn {
  from { opacity: 0; transform: scale(0.95); }
  to { opacity: 1; transform: scale(1); }
}

/* Mobile tweaks */
@media (max-width: 640px) {
  .container { padding: 0 20px; }

  /* Increase content spacing for breathing room */
  .content { padding-top: 40px; }

  .content-panel {
    padding: 20px 20px 32px;
  }

  .header-inner {
    display: flex;
    align-items: center;
    justify-content: flex-start;
    padding: 12px 20px;
    min-height: 56px;
  }

  .hamburger {
    position: static;
    transform: none;
    margin: 0 16px 0 0;
    padding: 8px 0;
    flex-shrink: 0;
  }
  /* Thinner, more elegant bars for mobile */
  .hamburger span { height: 1.5px; width: 22px; }

  .branding {
    text-align: left;
    flex: 1;
    padding: 0;
    min-width: 0; /* Enable ellipsis */
  }
  
  .branding .site-title {
    display: block;
    font-size: 1rem;
    line-height: 1.2;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
  }

  .site-tagline {
    display: none; /* Hide tagline on mobile for cleaner look */
  }

  .site-nav {
    display: flex;
    align-items: center;
    margin-left: auto;
  }
  .share-page-btn {
    padding: 8px;
    margin: 0;
  }
  .install-button { display: none; } /* Keep header clean, trigger from JS if needed elsewhere */

  h1 { font-size: 1.9rem; }
  h2 { font-size: 1.35rem; }
  h3 { font-size: 1.0rem; }

  ul, ol { padding-left: 1rem; }
  hr { margin: 1.25rem 0; }
  body { font-size: 18px; }
}

/* Desktop Sidebar Layout */
@media (min-width: 1024px) {
  body {
    padding-left: 320px; /* Space for sidebar */
  }

  .drawer {
    transform: translateX(0); /* Always show */
    width: 320px;
    max-width: 320px;
    box-shadow: none;
    border-right: 1px solid var(--border);
    /* Ensure it sits above standard flow but below overlays if any */
    z-index: 100; 
  }

  .drawer-close {
    display: none;
  }

  .hamburger {
    display: none;
  }

  .backdrop {
    display: none !important;
  }

  .container {
    max-width: 800px; /* Optimal reading width in the content area */
  }
}