/* Muhammad Bilal / kernel portfolio
   Theme: warm black, off-white prose, mauve lines, iris accent.
   Reading experience follows the v12.sh editorial layout: numbered
   headings, right rail table of contents, dark code frames. */

:root {
  --bg: #121113;
  --bg-raised: #17161a;
  --panel: #1a191f;
  --fg: #fdfcfd;
  --muted: #9d99a8;
  --faint: #6f6b7a;
  --border: #272530;
  --border-strong: #383546;
  --iris: #c4a7e7;
  --iris-dim: #a48ecf;
  --green: #73b362;
  --green-bg: #13580c40;
  --red: #f48374;
  --red-bg: #8b272340;
  --code-bg: #23222b;
  --code-fg: #e0def4;
  --code-gutter: #908caa;
  --sel: #817c9c26;
  --prose: 42rem;
  --shell: 72rem;
  --mono: "JetBrains Mono", ui-monospace, "DM Mono", monospace;
  --sans: "Inter", system-ui, -apple-system, sans-serif;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; text-size-adjust: 100%; }
/* clip (not hidden) so sideways junk never drags the page, without
   breaking position:sticky for the TOC rail */
html, body { overflow-x: clip; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--fg);
  font-family: var(--sans);
  font-size: 16px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}
a { color: inherit; text-decoration: none; }
::selection { background: var(--sel); }

.shell { max-width: var(--shell); margin: 0 auto; padding: 0 1.5rem; }

/* ---------- top nav ---------- */
.nav {
  display: flex; align-items: center; justify-content: space-between;
  height: 4.25rem; border-bottom: 1px solid var(--border);
}
.brand { font-family: var(--mono); font-size: 13px; letter-spacing: 0.02em; }
.brand b { font-weight: 600; }
.brand span { color: var(--faint); }
.nav-links { display: flex; gap: 1.6rem; }
.nav-links a {
  font-family: var(--mono); font-size: 11px; letter-spacing: 0.08em;
  text-transform: uppercase; color: var(--muted); transition: color 0.15s;
}
.nav-links a:hover, .nav-links a[aria-current="page"] { color: var(--fg); }

/* ---------- home: intro + numbered lists ---------- */
.home-head { padding-block: 5rem 3.5rem; border-bottom: 1px solid var(--border); }
.home-head .kicker {
  font-family: var(--mono); font-size: 11px; letter-spacing: 0.1em;
  text-transform: uppercase; color: var(--iris); margin: 0 0 1.1rem;
}
.home-head h1 {
  font-size: clamp(2rem, 4.4vw, 3.3rem); line-height: 1.08;
  letter-spacing: -0.02em; margin: 0 0 1.4rem; font-weight: 650;
  max-width: 40rem;
}
.home-head p { color: var(--muted); max-width: 38rem; margin: 0 0 1.4rem; }
.home-head .tagline {
  color: var(--fg); font-weight: 600; letter-spacing: -0.005em;
  margin: 2rem 0 0; max-width: 38rem;
}
.home-links { display: flex; flex-wrap: wrap; gap: 0.9rem 1.4rem; }
.home-links a {
  font-family: var(--mono); font-size: 11px; letter-spacing: 0.06em;
  text-transform: uppercase; color: var(--muted);
  border-bottom: 1px solid var(--border-strong); padding-bottom: 2px;
}
.home-links a:hover { color: var(--fg); border-color: var(--fg); }

.section-block { padding-block: 3.2rem 1.4rem; }
.section-label {
  display: flex; align-items: baseline; justify-content: space-between;
  margin-bottom: 0.4rem;
}
.section-label h2 {
  font-family: var(--mono); font-size: 11px; letter-spacing: 0.12em;
  text-transform: uppercase; color: var(--muted); margin: 0; font-weight: 500;
}
.section-label .count { font-family: var(--mono); font-size: 11px; color: var(--faint); }

.entry {
  display: grid;
  grid-template-columns: 3.2rem 7.5rem 1fr;
  gap: 1.2rem;
  padding: 1.15rem 0;
  border-bottom: 1px solid var(--border);
  align-items: baseline;
}
.entry:hover .entry-title { color: var(--iris); }
.entry-num {
  font-family: var(--mono); font-size: 13px; color: var(--faint);
  font-variant-numeric: tabular-nums;
}
.entry-date {
  font-family: var(--mono); font-size: 11px; color: var(--faint);
  text-transform: uppercase; letter-spacing: 0.04em;
}
.entry-title {
  font-size: 1.12rem; font-weight: 600; letter-spacing: -0.01em;
  margin: 0 0 0.15rem; transition: color 0.15s;
}
.entry-desc { color: var(--muted); font-size: 0.9rem; margin: 0; }
.entry-tag {
  font-family: var(--mono); font-size: 10px; color: var(--iris-dim);
  text-transform: uppercase; letter-spacing: 0.06em; margin-right: 0.5em;
}

/* ---------- reading mode: article replaces the home index ---------- */
body.reading .home-head,
body.reading .section-block { display: none; }
/* article pages run a minimal header, like the reference site: brand only */
body.reading .nav-links { display: none; }

/* ---------- article layout: prose + toc rail ---------- */
.article { padding-block: 3.5rem 6rem; }
.article-top {
  display: flex; align-items: center; justify-content: space-between;
  border-bottom: 1px solid var(--border); padding-bottom: 1.1rem; margin-bottom: 3rem;
}
.back-link {
  font-family: var(--mono); font-size: 11px; text-transform: uppercase;
  letter-spacing: 0.08em; color: var(--muted);
}
.back-link:hover { color: var(--fg); }
.article-kind {
  font-family: var(--mono); font-size: 11px; text-transform: uppercase;
  letter-spacing: 0.1em; color: var(--iris);
}
/* header and prose share one centered column, TOC rides beside it */
.article-col { min-width: 0; }
.article-head { margin-bottom: 2.6rem; }
.article-head h1 {
  font-size: clamp(1.8rem, 4vw, 2.7rem); line-height: 1.12;
  letter-spacing: -0.02em; margin: 0 0 0.9rem; font-weight: 650;
  text-wrap: balance;
}
.article-head .dek { color: var(--muted); font-size: 1.02rem; margin: 0; }
.post-meta {
  font-family: var(--mono); font-size: 11px; color: var(--faint);
  text-transform: uppercase; letter-spacing: 0.06em; margin: 0 0 1.2rem;
}
.post-meta em, .post-meta .meta-accent { font-style: normal; color: var(--iris); }
.article-meta {
  display: flex; flex-wrap: wrap; gap: 1.6rem; margin: 1.6rem 0 0;
  font-family: var(--mono); font-size: 11px; color: var(--faint);
  text-transform: uppercase; letter-spacing: 0.05em;
}

.article-grid { display: grid; grid-template-columns: minmax(0, var(--prose)) 13rem; gap: 4rem; justify-content: center; }
/* standalone pages have no TOC rail: one centered column */
.article-grid.solo { grid-template-columns: minmax(0, var(--prose)); }
.toc { position: sticky; top: 2rem; align-self: start; padding-top: 0.2rem; }
.toc-title {
  font-family: var(--mono); font-size: 10px; letter-spacing: 0.12em;
  text-transform: uppercase; color: var(--faint); margin: 0 0 0.7rem;
}
.toc a {
  display: block; font-family: var(--mono); font-size: 11px; line-height: 1.5;
  color: var(--muted); padding: 0.18rem 0 0.18rem 0.7rem;
  border-left: 1px solid var(--border);
}
.toc a:hover, .toc a.active { color: var(--fg); border-left-color: var(--iris); }
.toc a.lvl3 { padding-left: 1.4rem; font-size: 10.5px; color: var(--faint); }

/* ---------- prose ---------- */
.prose { counter-reset: chapter; }
.prose > h2 { counter-increment: chapter; counter-reset: section; }
.prose > h3 { counter-increment: section; }
.prose h2, .prose h3 { scroll-margin-top: 2rem; }
.prose > h2::before {
  content: counter(chapter) ".";
  color: var(--faint); margin-right: 0.7ch;
  font-variant-numeric: tabular-nums; font-weight: 500;
}
.prose > h3::before {
  content: counter(chapter) "." counter(section);
  color: var(--faint); margin-right: 0.7ch;
  font-variant-numeric: tabular-nums; font-weight: 500;
}
.prose h2 {
  font-size: 1.35rem; font-weight: 620; letter-spacing: -0.01em;
  margin: 2.4em 0 0.7em; padding-bottom: 0.35em;
  border-bottom: 1.5px solid var(--border); line-height: 1.25;
}
.prose h3 { font-size: 1.1rem; font-weight: 600; margin: 1.9em 0 0.55em; }
.prose p { margin: 0 0 1.05em; }
.prose p, .prose li { color: #d8d5de; }
.prose strong { color: var(--fg); font-weight: 640; }
.prose a { color: var(--iris-dim); border-bottom: 1px solid var(--border-strong); }
.prose a:hover { color: var(--iris); border-color: var(--iris); }
.prose ul, .prose ol { padding-left: 1.4rem; margin: 0 0 1.05em; }
.prose li { margin-bottom: 0.4em; }
.prose li::marker { color: var(--faint); }
.prose code {
  font-family: var(--mono); font-size: 0.85em; color: var(--code-fg);
  background: var(--code-bg); border: 1px solid var(--border);
  border-radius: 4px; padding: 0.1em 0.35em;
}
.prose pre {
  background: var(--code-bg); border: 1px solid var(--border);
  border-radius: 8px; padding: 1.1rem 1.2rem; overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  margin: 0 0 1.3em; font: 12.5px/1.7 var(--mono); color: var(--code-fg);
}
.prose pre code { background: none; border: 0; padding: 0; font-size: inherit; color: inherit; }
.prose pre .added { display: block; color: var(--green); background: var(--green-bg); }
.prose pre .removed { display: block; color: var(--red); background: var(--red-bg); }
/* syntax tones, matched to the v12.sh dark code frames */
.prose pre .k { color: var(--iris); }
.prose pre .s { color: #f6c177; }
.prose pre .c { color: var(--code-gutter); font-style: italic; }
.prose pre .n { color: #ebbcba; }
.prose pre .p { color: #9ccfd8; }
.prose blockquote {
  border-left: 2px solid var(--border-strong); margin: 0 0 1.05em;
  padding-left: 1.1rem; color: var(--muted);
}
.prose figure.fig { margin: 1.8em 0; }
.prose figure.fig img {
  display: block; max-width: 100%; height: auto;
  border: 1px solid #c9c9be; border-radius: 8px;
  background: #fafaf6;
}
.prose figure.fig figcaption {
  margin-top: 0.6rem; font-family: var(--mono); font-size: 0.68rem;
  letter-spacing: 0.08em; text-transform: uppercase; color: var(--faint);
  text-align: center;
}
.prose hr { border: 0; border-top: 1.5px solid var(--border); margin: 2.5em 0; }
.prose table {
  border-collapse: collapse; width: 100%; margin: 0 0 1.3em; font-size: 0.88rem;
  border: 1.5px solid var(--border-strong);
}
.prose table th {
  font-family: var(--mono); font-size: 0.68rem; text-transform: uppercase;
  letter-spacing: 0.08em; color: var(--muted); text-align: left;
  padding: 0.55rem 0.75rem; border: 1px solid var(--border-strong);
  background: var(--panel);
}
.prose table td {
  padding: 0.55rem 0.75rem; border: 1px solid var(--border-strong);
  color: #d8d5de; vertical-align: top;
}
.prose table td code { white-space: nowrap; }
.prose table tbody tr:nth-child(even) td { background: #17161c; }

.callout {
  border-left: 2px solid var(--iris); background: var(--panel);
  padding: 0.9rem 1.1rem; margin: 0 0 1.3em; color: #d8d5de; font-size: 0.95rem;
}
.callout b { color: var(--iris); font-family: var(--mono); font-size: 0.72rem;
  text-transform: uppercase; letter-spacing: 0.1em; display: block; margin-bottom: 0.3rem; }

.refs { border-top: 1px solid var(--border); margin-top: 3rem; padding-top: 1.2rem; }
.refs b {
  font-family: var(--mono); font-size: 10px; letter-spacing: 0.12em;
  text-transform: uppercase; color: var(--faint); display: block; margin-bottom: 0.6rem;
}
.refs a {
  font-family: var(--mono); font-size: 11px; color: var(--iris-dim);
  display: block; padding: 0.22rem 0; overflow-wrap: break-word;
}
.refs a:hover { color: var(--iris); }
.prose a { overflow-wrap: break-word; }

/* ---------- about ---------- */
.about-body { max-width: var(--prose); padding-block: 3.5rem 6rem; }
.about-body h1 { font-size: clamp(1.9rem, 4vw, 2.8rem); letter-spacing: -0.02em; margin: 0 0 1.2rem; font-weight: 650; }
.about-body .dek { color: var(--muted); font-size: 1.05rem; margin: 0 0 1.6rem; max-width: 40rem; }
.fact-row { display: flex; flex-wrap: wrap; gap: 2rem; margin: 1.4rem 0 2.6rem; }
.fact-row div { font-family: var(--mono); font-size: 11px; color: var(--faint); text-transform: uppercase; letter-spacing: 0.05em; }
.fact-row strong { display: block; color: var(--fg); font-size: 14px; margin-top: 0.3rem; }

/* ---------- footer ---------- */
.footer {
  border-top: 1px solid var(--border); margin-top: 2rem;
  padding-block: 2rem 3rem; display: flex; justify-content: space-between;
  gap: 1.5rem; flex-wrap: wrap; color: var(--muted);
  font-family: var(--mono); font-size: 11px;
}
.footer a { color: var(--muted); }
.footer a:hover { color: var(--fg); }
.footer .right { display: flex; gap: 1.4rem; }

.footnote { color: var(--faint); font-family: var(--mono); font-size: 10.5px; margin-top: 4rem; }

a:focus-visible, button:focus-visible { outline: 2px solid var(--iris); outline-offset: 3px; }

@media (max-width: 56rem) {
  .article-grid { grid-template-columns: minmax(0, 1fr); }
  .toc { display: none; }
  .entry { grid-template-columns: 2.4rem 1fr; }
  .entry-date { grid-column: 2; order: 3; }
  .entry-num { grid-row: 1; }
  .article { padding-block: 2.2rem 5rem; }
  .prose pre { font-size: 11.5px; padding: 0.9rem 1rem; }
  .prose code { font-size: 0.82em; }
}
@media (max-width: 40rem) {
  /* keep navigation on phones: brand on the first row, links in a
     horizontally scrollable row underneath, with finger sized targets */
  .nav { flex-wrap: wrap; height: auto; padding-block: 0.55rem; row-gap: 0.15rem; }
  .nav-links {
    display: flex; order: 2; width: 100%;
    flex-wrap: wrap; gap: 0.55rem 1.15rem;
    padding-block: 0.35rem 0.45rem;
  }
  .nav-links a { padding: 0.5rem 0; font-size: 11px; white-space: nowrap; }
  .back-link { display: inline-block; padding: 0.5rem 0; }
  .home-links { flex-direction: column; gap: 0; }
  .home-links a { padding: 0.55rem 0; align-self: flex-start; }
  .footer .right a { padding: 0.45rem 0; display: inline-block; }
  .home-head { padding-block: 3rem 2.2rem; }
  .home-head h1 { font-size: clamp(1.7rem, 8.5vw, 2.2rem); }
  .home-head p { margin-bottom: 1rem; }
  .home-head .tagline { margin-top: 1.4rem; }
  .entry { padding: 0.95rem 0; }
  .entry-desc { font-size: 0.85rem; }
  .fact-row { gap: 1.2rem 1.6rem; }
  .prose { font-size: 15.5px; }
}
/* touch feedback: entry titles light up on tap, hover states are desktop only */
.entry:active .entry-title { color: var(--iris); }
.toc a:active { color: var(--fg); }