@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700&family=JetBrains+Mono:wght@400;500&display=swap');

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

:root {
  --bg: #fafafa;
  --bg-surface: #ffffff;
  --text: #1a1a1a;
  --text-secondary: #666;
  --border: #e5e5e5;
  --accent: #2563eb;
  --code-bg: #f3f4f6;
  --tui-bg: #1e1e2e;
  --tui-border: #313244;
  --tui-text: #cdd6f4;
}

[data-theme="dark"] {
  --bg: #111113;
  --bg-surface: #1a1a1e;
  --text: #e4e4e7;
  --text-secondary: #a1a1aa;
  --border: #27272a;
  --accent: #60a5fa;
  --code-bg: #27272a;
  --tui-bg: #0a0a0c;
  --tui-border: #27272a;
}

body {
  background: var(--bg);
  color: var(--text);
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  font-size: 16px;
  line-height: 1.75;
  transition: background 0.2s, color 0.2s;
}

/* Layout */
.container { max-width: 680px; margin: 0 auto; padding: 1rem 1.5rem 4rem; }

/* Header */
header {
  max-width: 680px;
  margin: 0 auto;
  padding: 2rem 1.5rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.logo {
  font-weight: 700;
  font-size: 1.1rem;
  color: var(--text);
  text-decoration: none;
}

nav { display: flex; align-items: center; gap: 0.25rem; }

nav a {
  color: var(--text-secondary);
  text-decoration: none;
  margin-left: 1.5rem;
  font-size: 0.9rem;
  font-weight: 500;
}

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

.theme-toggle {
  background: var(--bg-surface);
  border: 1px solid var(--border);
  color: var(--text-secondary);
  padding: 4px 10px;
  border-radius: 6px;
  cursor: pointer;
  font-size: 0.8rem;
  font-family: inherit;
  margin-left: 1.5rem;
  transition: border-color 0.2s;
}

.theme-toggle:hover { border-color: var(--accent); color: var(--accent); }

/* Footer */
footer {
  max-width: 680px;
  margin: 0 auto;
  border-top: 1px solid var(--border);
  padding: 2rem 1.5rem;
  text-align: center;
  color: var(--text-secondary);
  font-size: 0.85rem;
}

footer a { color: var(--text-secondary); text-decoration: none; }
footer a:hover { color: var(--accent); }

/* Typography */
h1 {
  font-size: 2rem;
  font-weight: 700;
  line-height: 1.25;
  margin-bottom: 0.75rem;
  letter-spacing: -0.02em;
  color: var(--text);
}

h2 {
  font-size: 1.35rem;
  font-weight: 600;
  margin: 2.5rem 0 1rem;
  letter-spacing: -0.01em;
  color: var(--text);
}

h3 {
  font-size: 1.1rem;
  font-weight: 600;
  margin: 1.5rem 0 0.75rem;
  color: var(--text);
}

p { margin-bottom: 1.25rem; color: var(--text-secondary); }

a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }

.subtitle {
  color: var(--text-secondary);
  font-size: 1.1rem;
  line-height: 1.6;
  margin-bottom: 2.5rem;
  padding-bottom: 2rem;
  border-bottom: 1px solid var(--border);
}

blockquote {
  border-left: 3px solid var(--accent);
  padding-left: 1.25rem;
  color: var(--text-secondary);
  margin: 1.5rem 0;
  font-style: italic;
}

code {
  background: var(--code-bg);
  color: var(--accent);
  padding: 2px 6px;
  border-radius: 4px;
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.85em;
}

ul, ol { margin: 0 0 1.25rem 1.5rem; color: var(--text-secondary); }
li { margin-bottom: 0.5rem; }

/* Post meta */
.post-meta {
  color: var(--text-secondary);
  font-size: 0.875rem;
  margin-bottom: 1rem;
  display: flex;
  align-items: center;
  gap: 0.75rem;
  flex-wrap: wrap;
}

.tag {
  background: var(--code-bg);
  color: var(--text-secondary);
  padding: 2px 10px;
  border-radius: 12px;
  font-size: 0.8rem;
  font-weight: 500;
}

/* TUI blocks */
.tui-block {
  background: var(--tui-bg);
  border: 1px solid var(--tui-border);
  border-radius: 8px;
  padding: 1.5rem;
  margin: 1.5rem 0;
  overflow-x: auto;
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.8rem;
  line-height: 1.6;
  color: var(--tui-text);
  white-space: pre;
}

.tui-block .prompt { color: #a6e3a1; }
.tui-block .dim    { color: #585b70; }
.tui-block .info   { color: #89b4fa; }
.tui-block .warn   { color: #f9e2af; }
.tui-block .bright  { color: #cdd6f4; }
.tui-block .err    { color: #f38ba8; }
.tui-block .accent { color: #cba6f7; }

/* Tier cards */
.tier-diagram {
  display: flex;
  gap: 1.25rem;
  margin: 2rem 0;
}

.tier-card {
  flex: 1;
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 1.25rem;
  background: var(--bg-surface);
}

.tier-card h3 {
  font-size: 0.85rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: 0.5rem;
  font-weight: 600;
}

.tier-card.hot h3  { color: #dc2626; }
.tier-card.warm h3 { color: #d97706; }
.tier-card.cold h3 { color: #2563eb; }

[data-theme="dark"] .tier-card.hot h3  { color: #f87171; }
[data-theme="dark"] .tier-card.warm h3 { color: #fbbf24; }
[data-theme="dark"] .tier-card.cold h3 { color: #60a5fa; }

.tier-card .limit {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 0.25rem;
}

.tier-card p {
  color: var(--text-secondary);
  font-size: 0.85rem;
  margin: 0;
  line-height: 1.5;
}

/* Post listing */
.post-list { list-style: none; padding: 0; margin: 2rem 0 0; }

.post-item {
  border-bottom: 1px solid var(--border);
  padding: 1.5rem 0;
}

.post-item:first-child { border-top: 1px solid var(--border); }

.post-item a {
  text-decoration: none;
  color: var(--text);
  font-size: 1.2rem;
  font-weight: 600;
  display: block;
  margin-bottom: 0.5rem;
}

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

.post-item .excerpt {
  color: var(--text-secondary);
  font-size: 0.95rem;
  line-height: 1.6;
  margin-bottom: 0.5rem;
}

.post-item .post-meta { margin-bottom: 0; }

/* Flow diagrams (stylized TUI) */
.flow-diagram {
  background: var(--tui-bg);
  border: 1px solid var(--tui-border);
  border-radius: 8px;
  padding: 2rem;
  margin: 1.5rem 0;
  overflow-x: auto;
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.75rem;
  line-height: 1.5;
  color: var(--tui-text);
  white-space: pre;
  text-align: center;
}

/* Platform grid */
.platform-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 0.75rem;
  margin: 1.5rem 0;
}

.platform-badge {
  background: var(--bg-surface);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 0.75rem;
  text-align: center;
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--text);
}

/* Responsive */
@media (max-width: 640px) {
  h1 { font-size: 1.5rem; }
  .tier-diagram { flex-direction: column; }
  .platform-grid { grid-template-columns: repeat(2, 1fr); }
  header { flex-wrap: wrap; gap: 1rem; }
  .tui-block, .flow-diagram { font-size: 0.7rem; padding: 1rem; }
}