/* ============================================================
   jath.cl — Technical theme
   Dark by default. Clean, code-first, no ornament.
   Built on PicoCSS classless foundation.
   ============================================================ */

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

/* ── Color tokens ── */
:root,
[data-theme="dark"] {
  --bg:            #0d0f12;
  --bg-surface:    #141720;
  --bg-elevated:   #1a1f2e;
  --border:        #1e2330;
  --border-bright: #2a3050;
  --accent:        #4da8da;
  --accent-dim:    #2d6a8a;
  --text:          #b0b8cc;
  --text-heading:  #e8eaf0;
  --text-muted:    #4a526a;
  --code-bg:       #111318;
  --tag-bg:        #1a1f2e;
  --tag-color:     #6a8aaa;

  --pico-background-color:      var(--bg);
  --pico-card-background-color: var(--bg-surface);
  --pico-card-border-color:     var(--border);
  --pico-color:                 var(--text);
  --pico-h1-color:              var(--text-heading);
  --pico-h2-color:              var(--text-heading);
  --pico-h3-color:              var(--accent);
  --pico-primary:               var(--accent);
  --pico-primary-hover:         #7ac4e8;
  --pico-secondary-color:       var(--text-muted);
  --pico-border-color:          var(--border);
  --pico-muted-color:           var(--text-muted);
  --pico-muted-border-color:    var(--border);
  --pico-code-background-color: var(--code-bg);
  --pico-code-color:            var(--accent);
}

[data-theme="light"] {
  --bg:            #ffffff;
  --bg-surface:    #f5f7fa;
  --bg-elevated:   #edf0f5;
  --border:        #e2e5ec;
  --border-bright: #c8cdd8;
  --accent:        #0066cc;
  --accent-dim:    #3388dd;
  --text:          #2d3244;
  --text-heading:  #0f1117;
  --text-muted:    #8090a8;
  --code-bg:       #f0f2f6;
  --tag-bg:        #edf0f5;
  --tag-color:     #4466aa;

  --pico-background-color:      var(--bg);
  --pico-card-background-color: var(--bg-surface);
  --pico-card-border-color:     var(--border);
  --pico-color:                 var(--text);
  --pico-h1-color:              var(--text-heading);
  --pico-h2-color:              var(--text-heading);
  --pico-h3-color:              var(--accent);
  --pico-primary:               var(--accent);
  --pico-primary-hover:         var(--accent-dim);
  --pico-secondary-color:       var(--text-muted);
  --pico-border-color:          var(--border);
  --pico-muted-color:           var(--text-muted);
  --pico-muted-border-color:    var(--border);
  --pico-code-background-color: var(--code-bg);
  --pico-code-color:            var(--accent);
}

/* ── Base ── */
html { scroll-behavior: smooth; }

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  background-color: var(--bg);
  color: var(--text);
  min-height: 100vh;
  font-size: 1rem;
  line-height: 1.7;
}

h1, h2, h3, h4, h5, h6 {
  font-family: 'Inter', sans-serif;
  color: var(--text-heading);
  font-weight: 700;
  line-height: 1.25;
  letter-spacing: -0.01em;
}

h1 { font-size: 2rem;   margin-bottom: 0.5rem; }
h2 { font-size: 1.45rem; margin-top: 2rem; }
h3 { font-size: 1.15rem; color: var(--accent); }

a {
  color: var(--accent);
  text-decoration: none;
  transition: color 0.15s ease;
}
a:hover { color: var(--pico-primary-hover); text-decoration: underline; }

code, kbd {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.875em;
  background: var(--code-bg);
  color: var(--accent);
  padding: 0.1em 0.35em;
  border-radius: 3px;
}

pre {
  background: var(--code-bg) !important;
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: 1.25rem 1.5rem;
  overflow-x: auto;
  font-size: 0.875rem;
  line-height: 1.6;
}

pre code {
  background: transparent;
  padding: 0;
  color: inherit;
  font-size: inherit;
}

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

table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.9rem;
}
th, td {
  border: 1px solid var(--border);
  padding: 0.5rem 0.75rem;
  text-align: left;
}
th {
  background: var(--bg-surface);
  font-weight: 600;
  color: var(--text-heading);
}

hr {
  border: none;
  border-top: 1px solid var(--border);
  margin: 2rem 0;
}

/* ── Navigation ── */
nav.site-nav {
  background: var(--bg-surface);
  border-bottom: 1px solid var(--border);
  padding: 0.75rem 0;
  position: sticky;
  top: 0;
  z-index: 100;
}

.nav-inner {
  max-width: 900px;
  margin: 0 auto;
  padding: 0 1.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  flex-wrap: wrap;
}

.nav-brand {
  font-family: 'JetBrains Mono', monospace;
  font-size: 1rem;
  font-weight: 500;
  color: var(--text-heading) !important;
  text-decoration: none !important;
  letter-spacing: -0.02em;
}
.nav-brand:hover { color: var(--accent) !important; text-decoration: none !important; }

.nav-links {
  display: flex;
  gap: 1.5rem;
  list-style: none;
  margin: 0;
  padding: 0;
}
.nav-links a {
  font-size: 0.875rem;
  color: var(--text-muted);
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.06em;
}
.nav-links a:hover { color: var(--text); text-decoration: none; }

.nav-controls {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.lang-btn, .theme-btn {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.75rem;
  color: var(--text-muted);
  border: 1px solid var(--border-bright);
  background: transparent;
  padding: 0.25rem 0.6rem;
  border-radius: 3px;
  cursor: pointer;
  letter-spacing: 0.04em;
  transition: border-color 0.15s, color 0.15s;
  line-height: 1.5;
}
.lang-btn:hover, .theme-btn:hover {
  color: var(--accent);
  border-color: var(--accent);
  text-decoration: none;
}

/* ── Container ── */
.container {
  max-width: 900px;
  margin: 0 auto;
  padding: 2rem 1.5rem;
}

/* ── Page header (index) ── */
.page-header {
  margin-bottom: 2rem;
  padding-bottom: 1.5rem;
  border-bottom: 1px solid var(--border);
}

.page-header h1 { margin-bottom: 0.25rem; }

.page-subtitle {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.8rem;
  color: var(--text-muted);
  letter-spacing: 0.04em;
  margin: 0;
}

/* ── Post list / cards ── */
.post-list {
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}

.post-card {
  background: var(--bg-surface);
  border: 1px solid var(--border);
  border-left: 3px solid var(--border-bright);
  padding: 1.5rem 1.75rem;
  transition: border-left-color 0.15s, background 0.15s;
}
.post-card:hover {
  border-left-color: var(--accent);
  background: var(--bg-elevated);
}

.post-card h2 {
  font-size: 1.2rem;
  margin: 0 0 0.35rem;
}
.post-card h2 a {
  color: var(--text-heading);
}
.post-card h2 a:hover {
  color: var(--accent);
  text-decoration: none;
}

.post-meta {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.75rem;
  color: var(--text-muted);
  letter-spacing: 0.03em;
  margin-bottom: 0.75rem;
  display: flex;
  align-items: center;
  gap: 0.25rem;
  flex-wrap: wrap;
}

.post-date { color: var(--text-muted); }
.reading-time { color: var(--text-muted); }

.post-description {
  font-size: 0.95rem;
  color: var(--text);
  line-height: 1.65;
  margin-bottom: 0.75rem;
}

.post-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.35rem;
  margin-bottom: 0.75rem;
}

.tag {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.7rem;
  color: var(--tag-color);
  background: var(--tag-bg);
  border: 1px solid var(--border);
  padding: 0.15rem 0.5rem;
  border-radius: 3px;
  text-decoration: none;
  letter-spacing: 0.03em;
  transition: border-color 0.15s, color 0.15s;
}
.tag:hover {
  border-color: var(--accent);
  color: var(--accent);
  text-decoration: none;
}

.read-more {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.8rem;
  color: var(--accent);
  letter-spacing: 0.03em;
}
.read-more:hover { text-decoration: none; opacity: 0.8; }

/* ── Individual post ── */
.post-header {
  margin-bottom: 2rem;
  padding-bottom: 1.5rem;
  border-bottom: 1px solid var(--border);
}
.post-header h1 {
  font-size: 2rem;
  margin: 0.35rem 0 0.5rem;
  line-height: 1.2;
}
.post-header .post-meta { margin-top: 0.5rem; }
.post-header .post-tags { margin-top: 0.75rem; }

.series-label {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.75rem;
  color: var(--accent);
  letter-spacing: 0.04em;
  text-transform: uppercase;
  display: block;
  margin-bottom: 0.35rem;
}

/* Post layout: body + optional ToC sidebar */
.post-layout {
  display: flex;
  gap: 3rem;
  align-items: flex-start;
}

.post-body {
  flex: 1;
  min-width: 0;
  max-width: 72ch;
  font-size: 1.0rem;
  line-height: 1.8;
}

.post-body h2 {
  margin-top: 2.5rem;
  padding-top: 0.5rem;
  border-top: 1px solid var(--border);
}
.post-body h3 { margin-top: 1.75rem; }

.post-body ul, .post-body ol {
  padding-left: 1.5rem;
}
.post-body li { margin-bottom: 0.25rem; }

.post-body img {
  max-width: 100%;
  border-radius: 4px;
  margin: 1rem 0;
}

/* ── Table of contents ── */
.toc-nav {
  position: sticky;
  top: 5rem;
  width: 220px;
  flex-shrink: 0;
  font-size: 0.825rem;
  align-self: flex-start;
  border-left: 2px solid var(--border);
  padding-left: 1rem;
}

.toc-label {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.7rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-muted);
  margin-bottom: 0.5rem;
}

.toc-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 0.2rem;
}

.toc-list a {
  color: var(--text-muted);
  font-size: 0.825rem;
  line-height: 1.4;
  display: block;
  padding: 0.1rem 0;
  transition: color 0.15s;
}
.toc-list a:hover { color: var(--accent); text-decoration: none; }

.toc-h2 { padding-left: 0; }
.toc-h3 { padding-left: 0.75rem; }

/* ── Series navigation ── */
.series-nav {
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  margin: 2.5rem 0;
  padding: 1rem 1.25rem;
  background: var(--bg-surface);
  border: 1px solid var(--border);
  border-radius: 4px;
}

.series-prev, .series-next {
  font-size: 0.875rem;
  color: var(--text-muted);
  max-width: 45%;
}
.series-prev:hover, .series-next:hover { color: var(--accent); text-decoration: none; }
.series-next { text-align: right; margin-left: auto; }

/* ── Code blocks ── */
.code-block {
  position: relative;
  margin: 1.5rem 0;
}

.code-lang {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.7rem;
  color: var(--text-muted);
  letter-spacing: 0.06em;
  text-transform: lowercase;
  display: block;
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-bottom: none;
  padding: 0.2rem 0.75rem;
  border-radius: 3px 3px 0 0;
  width: fit-content;
}

.code-block .highlight {
  margin: 0;
  border-radius: 0 4px 4px 4px;
}
.code-lang + .highlight { border-radius: 0 4px 4px 4px; }
.code-block:not(:has(.code-lang)) .highlight { border-radius: 4px; }

.copy-btn {
  position: absolute;
  top: 0.5rem;
  right: 0.5rem;
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.7rem;
  color: var(--text-muted);
  background: var(--bg-elevated);
  border: 1px solid var(--border-bright);
  padding: 0.2rem 0.5rem;
  border-radius: 3px;
  cursor: pointer;
  opacity: 0;
  transition: opacity 0.15s;
  line-height: 1.5;
}
.code-block:hover .copy-btn { opacity: 1; }
.copy-btn:hover { color: var(--accent); border-color: var(--accent); }

/* Pygments: override background to match theme */
.code-block .highlight pre {
  margin: 0;
  padding: 1.25rem 1.5rem;
  border: 1px solid var(--border);
  border-radius: 0 4px 4px 4px;
  overflow-x: auto;
  background: var(--code-bg) !important;
  font-size: 0.875rem;
  line-height: 1.6;
}

/* ── Post footer ── */
.post-footer {
  margin-top: 3rem;
  padding-top: 1.25rem;
  border-top: 1px solid var(--border);
}

.back-link {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.825rem;
  color: var(--text-muted);
  letter-spacing: 0.03em;
}
.back-link:hover { color: var(--accent); text-decoration: none; }

/* ── Tags page ── */
.tags-page { max-width: 700px; }
.tags-page h1 { margin-bottom: 1.5rem; }

.tag-cloud {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}
.tag-cloud li { display: flex; align-items: center; gap: 0.35rem; }

.tag-count {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.7rem;
  color: var(--text-muted);
}

/* ── About page ── */
.about-body {
  max-width: 72ch;
  font-size: 1.0rem;
  line-height: 1.8;
  margin-top: 1.5rem;
}
.about-body h2 {
  margin-top: 2rem;
  padding-bottom: 0.35rem;
  border-bottom: 1px solid var(--border);
}

/* ── Footer ── */
footer.site-footer {
  margin-top: 4rem;
  padding: 2rem 1.5rem;
  border-top: 1px solid var(--border);
  text-align: center;
}
footer.site-footer p {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.75rem;
  color: var(--text-muted);
  letter-spacing: 0.04em;
  margin: 0;
}

/* ── 404 ── */
.not-found {
  text-align: center;
  padding: 5rem 0;
}
.not-found h1 {
  font-size: 4rem;
  color: var(--accent);
  opacity: 0.4;
  margin-bottom: 0.5rem;
}

/* ── Responsive ── */
@media (max-width: 800px) {
  .post-layout { flex-direction: column; gap: 1.5rem; }
  .toc-nav {
    position: static;
    width: 100%;
    border-left: none;
    border-top: 1px solid var(--border);
    padding: 1rem 0 0;
  }
}

@media (max-width: 640px) {
  h1 { font-size: 1.6rem; }
  .nav-links { gap: 1rem; }
  .post-card { padding: 1.25rem; }
  .post-header h1 { font-size: 1.5rem; }
  .series-nav { flex-direction: column; }
  .series-next { text-align: left; margin-left: 0; }
}