/* ============================================================
   DESIGN SYSTEM
   ============================================================ */
:root {
  --ink:        #1a1814;
  --ink-light:  #5c554a;
  --ink-faint:  #9c9488;
  --paper:      #f7f4ef;
  --paper-warm: #f0ebe2;
  --paper-card: #faf8f4;
  --accent:     #b5470c;
  --accent-dim: #d4622a;
  --rule:       #e0d8ce;

  --font-display: 'Playfair Display', Georgia, serif;
  --font-body:    'IBM Plex Sans', system-ui, sans-serif;
  --font-mono:    'IBM Plex Mono', 'Courier New', monospace;

  --max-width: 1100px;
  --post-width: 680px;
}

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

html { font-size: 16px; scroll-behavior: smooth; }

body {
  background: var(--paper);
  color: var(--ink);
  font-family: var(--font-body);
  font-weight: 300;
  line-height: 1.7;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

a { color: inherit; text-decoration: none; }

/* ============================================================
   HEADER
   ============================================================ */
.site-header {
  border-bottom: 1px solid var(--rule);
  padding: 0 2rem;
  position: sticky;
  top: 0;
  background: color-mix(in srgb, var(--paper) 92%, transparent);
  backdrop-filter: blur(12px);
  z-index: 100;
}

.header-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 60px;
}

.site-title {
  font-family: var(--font-display);
  font-size: 1.15rem;
  font-weight: 700;
  letter-spacing: 0.01em;
  color: var(--ink);
  transition: color 0.2s;
}
.site-title:hover { color: var(--accent); }

.site-nav { display: flex; gap: 2rem; }

.nav-link {
  font-size: 0.8rem;
  font-weight: 500;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--ink-faint);
  transition: color 0.2s;
  padding-bottom: 2px;
  border-bottom: 1px solid transparent;
}
.nav-link:hover,
.nav-link.active {
  color: var(--ink);
  border-bottom-color: var(--ink);
}

/* ============================================================
   HERO
   ============================================================ */
.hero {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 5rem 2rem 3.5rem;
}

.hero-label {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  color: var(--accent);
  letter-spacing: 0.06em;
  margin-bottom: 1rem;
}

.hero-title {
  font-family: var(--font-display);
  font-size: clamp(2.8rem, 6vw, 4.8rem);
  font-weight: 700;
  line-height: 1.1;
  color: var(--ink);
}

.hero-title em {
  font-style: italic;
  color: var(--accent);
}

/* ============================================================
   POSTS GRID
   ============================================================ */
.posts-section {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 1rem 2rem 6rem;
  flex: 1;
}

.posts-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 1.5px;
  border: 1.5px solid var(--rule);
}

.post-card {
  background: var(--paper-card);
  border: none;
}

.card-link {
  display: block;
  padding: 2rem 2rem 1.75rem;
  height: 100%;
  border: 1.5px solid transparent;
  transition: background 0.2s, border-color 0.2s;
  position: relative;
  overflow: hidden;
}
.card-link::before {
  content: '';
  position: absolute;
  top: 0; left: 0;
  width: 3px;
  height: 100%;
  background: var(--accent);
  transform: scaleY(0);
  transform-origin: bottom;
  transition: transform 0.25s ease;
}
.card-link:hover { background: var(--paper-warm); }
.card-link:hover::before { transform: scaleY(1); }

.card-meta {
  display: flex;
  gap: 0.75rem;
  align-items: center;
  margin-bottom: 0.85rem;
  flex-wrap: wrap;
}

.card-category-sep,
.post-category-sep {
  font-size: 0.7rem;
  color: var(--ink-faint);
  margin: 0 2px;
  user-select: none;
}

.post-category-breadcrumb {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 0;
}

.card-category {
  font-family: var(--font-mono);
  font-size: 0.68rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--accent);
  background: color-mix(in srgb, var(--accent) 10%, transparent);
  padding: 0.2em 0.6em;
  border-radius: 2px;
}

.card-date {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--ink-faint);
}

.card-title {
  font-family: var(--font-display);
  font-size: 1.25rem;
  font-weight: 700;
  line-height: 1.3;
  color: var(--ink);
  margin-bottom: 0.75rem;
}

.card-preview {
  font-size: 0.875rem;
  color: var(--ink-light);
  line-height: 1.65;
  margin-bottom: 1.5rem;
}

.card-read {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.08em;
  color: var(--accent);
  display: block;
}

/* ============================================================
   LOADING & ERROR STATES
   ============================================================ */
.loading-state {
  display: flex;
  gap: 0.5rem;
  justify-content: center;
  padding: 4rem 0;
}

.loading-dot {
  width: 6px; height: 6px;
  border-radius: 50%;
  background: var(--ink-faint);
  animation: pulse 1.2s ease-in-out infinite;
}
.loading-dot:nth-child(2) { animation-delay: 0.2s; }
.loading-dot:nth-child(3) { animation-delay: 0.4s; }

@keyframes pulse {
  0%, 80%, 100% { transform: scale(0.7); opacity: 0.4; }
  40% { transform: scale(1); opacity: 1; }
}

.error-state {
  padding: 3rem 2rem;
  max-width: 500px;
  margin: 0 auto;
  text-align: center;
  font-family: var(--font-mono);
  font-size: 0.85rem;
  color: var(--ink-light);
  border: 1px dashed var(--rule);
}

/* ============================================================
   POST PAGE LAYOUT
   ============================================================ */
.post-layout {
  display: grid;
  grid-template-columns: 260px 1fr;
  max-width: var(--max-width);
  margin: 0 auto;
  flex: 1;
  width: 100%;
  padding: 0 1rem;
  gap: 3rem;
  align-items: start;
}

/* ---- SIDEBAR ---- */
.sidebar {
  position: sticky;
  top: 80px;
  padding: 2.5rem 0 2rem;
  border-right: 1px solid var(--rule);
  max-height: calc(100vh - 80px);
  overflow-y: auto;
}
.sidebar::-webkit-scrollbar { width: 4px; }
.sidebar::-webkit-scrollbar-track { background: transparent; }
.sidebar::-webkit-scrollbar-thumb { background: var(--rule); border-radius: 4px; }

.sidebar-inner { padding-right: 2rem; }

.back-link {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.06em;
  color: var(--ink-faint);
  display: inline-block;
  margin-bottom: 2rem;
  transition: color 0.2s;
}
.back-link:hover { color: var(--accent); }

.sidebar-heading {
  font-family: var(--font-mono);
  font-size: 0.65rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--ink-faint);
  margin-bottom: 1rem;
}

.sidebar-nav { display: flex; flex-direction: column; gap: 0; }

.sidebar-link {
  font-size: 0.82rem;
  color: var(--ink-light);
  padding: 0.5rem 0.75rem;
  border-radius: 3px;
  transition: background 0.15s, color 0.15s;
  line-height: 1.4;
  border-left: 2px solid transparent;
}
.sidebar-link:hover { background: var(--paper-warm); color: var(--ink); }
.sidebar-link.active {
  color: var(--accent);
  border-left-color: var(--accent);
  background: color-mix(in srgb, var(--accent) 6%, transparent);
}

.sidebar-loading {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--ink-faint);
  padding: 0.5rem 0.75rem;
}

/* ---- POST MAIN ---- */
.post-main {
  padding: 3rem 0 6rem;
  max-width: var(--post-width);
}

.post-header { margin-bottom: 3rem; }

.post-header-meta {
  display: flex;
  gap: 0.75rem;
  align-items: center;
  flex-wrap: wrap;
  margin-bottom: 1rem;
}

.post-category {
  font-family: var(--font-mono);
  font-size: 0.68rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--accent);
  background: color-mix(in srgb, var(--accent) 10%, transparent);
  padding: 0.2em 0.6em;
  border-radius: 2px;
}

.post-date {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  color: var(--ink-faint);
}

.post-title {
  font-family: var(--font-display);
  font-size: clamp(2rem, 4vw, 3rem);
  font-weight: 700;
  line-height: 1.2;
  color: var(--ink);
}

/* ---- POST BODY TYPOGRAPHY ---- */
.post-body {
  font-size: 1.0625rem;
  line-height: 1.8;
  color: var(--ink);
}

.post-body h2 {
  font-family: var(--font-display);
  font-size: 1.65rem;
  font-weight: 700;
  margin: 2.75rem 0 1rem;
  color: var(--ink);
}

.post-body h3 {
  font-family: var(--font-display);
  font-size: 1.25rem;
  font-weight: 700;
  font-style: italic;
  margin: 2.25rem 0 0.75rem;
  color: var(--ink);
}

.post-body h4 {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--ink-light);
  margin: 2rem 0 0.5rem;
}

.post-body p { margin-bottom: 1.4rem; }

.post-body a {
  color: var(--accent);
  text-decoration: underline;
  text-decoration-color: color-mix(in srgb, var(--accent) 40%, transparent);
  text-underline-offset: 3px;
  transition: text-decoration-color 0.2s;
}
.post-body a:hover { text-decoration-color: var(--accent); }

.post-body strong { font-weight: 500; color: var(--ink); }
.post-body em { font-style: italic; }

.post-body code {
  font-family: var(--font-mono);
  font-size: 0.875em;
  background: var(--paper-warm);
  border: 1px solid var(--rule);
  padding: 0.1em 0.4em;
  border-radius: 3px;
  color: var(--accent);
}

.post-body pre {
  background: var(--ink);
  color: #d4c9b8;
  padding: 1.5rem;
  border-radius: 4px;
  overflow-x: auto;
  margin: 1.5rem 0;
  font-family: var(--font-mono);
  font-size: 0.85rem;
  line-height: 1.6;
}
.post-body pre code {
  background: none;
  border: none;
  padding: 0;
  color: inherit;
  font-size: inherit;
}

.post-body blockquote {
  border-left: 3px solid var(--accent);
  padding: 0.25rem 0 0.25rem 1.5rem;
  margin: 1.75rem 0;
  color: var(--ink-light);
  font-style: italic;
}

.post-body ul, .post-body ol {
  padding-left: 1.5rem;
  margin-bottom: 1.4rem;
}
.post-body li { margin-bottom: 0.4rem; }
.post-body ul li::marker { color: var(--accent); }

.post-body hr {
  border: none;
  border-top: 1px solid var(--rule);
  margin: 2.5rem 0;
}

.post-body img {
  max-width: 100%;
  border-radius: 4px;
  margin: 1.5rem 0;
}

.post-body table {
  width: 100%;
  border-collapse: collapse;
  margin: 1.5rem 0;
  font-size: 0.9rem;
}
.post-body th {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--ink-faint);
  border-bottom: 2px solid var(--rule);
  padding: 0.5rem 0.75rem;
  text-align: left;
}
.post-body td {
  padding: 0.6rem 0.75rem;
  border-bottom: 1px solid var(--rule);
}

/* ---- POST NAV ---- */
.post-footer {
  margin-top: 4rem;
  padding-top: 2rem;
  border-top: 1px solid var(--rule);
}

.post-nav {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
  margin-bottom: 2rem;
}

.post-nav-link {
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
  padding: 1rem 1.25rem;
  background: var(--paper-card);
  border: 1px solid var(--rule);
  transition: border-color 0.2s, background 0.2s;
  border-radius: 3px;
}
.post-nav-link:hover { background: var(--paper-warm); border-color: var(--accent); }
.post-nav-link.next { text-align: right; }

.post-nav-link span:first-child {
  font-family: var(--font-mono);
  font-size: 0.68rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--ink-faint);
}
.post-nav-title {
  font-family: var(--font-display);
  font-size: 0.9rem;
  color: var(--ink);
  font-weight: 700;
}

.back-to-all {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--ink-faint);
  letter-spacing: 0.06em;
  transition: color 0.2s;
}
.back-to-all:hover { color: var(--accent); }

/* ============================================================
   FOOTER
   ============================================================ */
.site-footer {
  border-top: 1px solid var(--rule);
  padding: 1.75rem 2rem;
  text-align: center;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--ink-faint);
}
.site-footer a {
  color: var(--ink-light);
  text-decoration: underline;
  text-underline-offset: 2px;
}
.site-footer a:hover { color: var(--accent); }

/* ============================================================
   RESPONSIVE
   ============================================================ */
@media (max-width: 860px) {
  .post-layout {
    grid-template-columns: 1fr;
    padding: 0;
    gap: 0;
  }

  .sidebar {
    position: static;
    max-height: none;
    border-right: none;
    border-bottom: 1px solid var(--rule);
    padding: 1.25rem 1.5rem;
    overflow: visible;
  }

  .sidebar-inner { padding-right: 0; }

  .sidebar-heading, .sidebar-nav { display: none; }

  .back-link { margin-bottom: 0; }

  .post-main {
    padding: 2rem 1.5rem 4rem;
    max-width: 100%;
  }

  .post-nav { grid-template-columns: 1fr; }
  .post-nav-link.next { text-align: left; }
}

@media (max-width: 600px) {
  .hero { padding: 3rem 1.5rem 2rem; }
  .posts-section { padding: 1rem 0 4rem; }
  .posts-grid { gap: 1px; grid-template-columns: 1fr; border: none; }
  .post-card { border-bottom: 1px solid var(--rule); }
  .hero-title { font-size: 2.4rem; }
}