/* ════════════════════════════════════════════════════
   Rahulraj P V — portfolio
   Monograph register: index rail + typeset content.
   Fraunces / Inter, hairline rules, IKB accent.
   No animation — colour hovers only.
   ════════════════════════════════════════════════════ */

:root {
  --bg:       #faf9f6;
  --bg-rail:  #f5f3ee;
  --ink:      #191813;
  --ink-2:    #4c4a42;
  --ink-3:    #767263;
  --line:     #e3e0d6;
  --line-2:   #d4d0c3;
  --accent:   #1f3ab8;      /* International Klein-ish blue */
  --accent-2: #14297f;

  /* type scale — five sizes below the display faces */
  --fs-label: 0.72rem;   /* index numbers, small-caps groups, badges */
  --fs-meta:  0.88rem;   /* dates, venues, notes, abstracts, methods */
  --fs-body:  0.95rem;   /* list and entry body text */
  --fs-head:  1rem;      /* citations, entry heads, post titles */
  --fs-title: 1.12rem;   /* serif row titles */

  --serif: "Fraunces", Georgia, "Times New Roman", serif;
  --sans:  "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;

  --measure: 66ch;
  --rail-w: 300px;
  --gap: clamp(3rem, 7vw, 6.5rem);
  --pad: clamp(1.4rem, 5vw, 3rem);
}

:root[data-theme="dark"] {
  --bg:       #151412;
  --bg-rail:  #191815;
  --ink:      #eae7df;
  --ink-2:    #b6b2a6;
  --ink-3:    #8b8779;
  --line:     #2b2924;
  --line-2:   #3a372f;
  --accent:   #96a7f8;
  --accent-2: #b3c0fa;
}

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

html { -webkit-text-size-adjust: 100%; }

body {
  background: var(--bg);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 16.5px;
  font-weight: 450;
  line-height: 1.66;
  -webkit-font-smoothing: antialiased;
  border-top: 3px solid var(--accent);   /* signature hairline */
}

img, svg { max-width: 100%; display: block; }
button { font: inherit; color: inherit; background: none; border: 0; cursor: pointer; }
ul, ol { list-style: none; }

::selection { background: var(--accent); color: var(--bg); }

a {
  color: var(--accent);
  text-decoration: none;
}
a:hover { color: var(--accent-2); }

:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }

.skip-link {
  position: absolute;
  top: -100px; left: 1rem;
  z-index: 100;
  background: var(--accent);
  color: var(--bg);
  padding: 0.5rem 0.9rem;
  font-size: 0.85rem;
}
.skip-link:focus { top: 0.75rem; }

/* ════════════ LAYOUT ════════════ */
.layout {
  max-width: 1220px;
  margin-inline: auto;
  padding-inline: var(--pad);
  display: grid;
  grid-template-columns: var(--rail-w) minmax(0, 1fr);
  column-gap: var(--gap);
  align-items: start;
}

main { padding-block: clamp(3rem, 8vh, 5.5rem) 2rem; min-width: 0; }

/* ════════════ RAIL ════════════ */
.rail {
  position: sticky;
  top: 0;
  max-height: 100vh;
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  gap: 2.25rem;
  padding-block: clamp(3rem, 8vh, 5.5rem) 2rem;
  /* pull halfway into the column gap so the rule sits centred between rail and content */
  padding-right: calc(var(--gap) / 2);
  margin-right: calc(var(--gap) / -2);
  border-right: 1px solid var(--line);
  scrollbar-width: none;
}
.rail::-webkit-scrollbar { display: none; }

.rail__name {
  font-family: var(--serif);
  font-weight: 500;
  font-size: 1.55rem;
  letter-spacing: -0.01em;
  color: var(--ink);
  text-decoration: none;
  display: inline-block;
  line-height: 1.1;
}
.rail__name:hover { color: var(--accent); }

.rail__role {
  margin-top: 0.8rem;
  font-size: var(--fs-meta);
  line-height: 1.55;
  color: var(--ink-3);
}

/* contents */
.toc ol { counter-reset: toc; display: grid; gap: 0.05rem; }
.toc li { counter-increment: toc; }
.toc a {
  display: flex;
  align-items: baseline;
  gap: 0.8rem;
  padding: 0.32rem 0;
  font-size: var(--fs-meta);
  color: var(--ink-2);
  text-decoration: none;
  border-bottom: 1px solid var(--line);
}
.toc li:first-child a { border-top: 1px solid var(--line); }
.toc a::before {
  content: counter(toc, decimal-leading-zero);
  font-size: var(--fs-label);
  color: var(--ink-3);
  font-variant-numeric: tabular-nums;
}
.toc a:hover { color: var(--accent); }
.toc a:hover::before { color: var(--accent); }
.toc a.is-active { color: var(--accent); }
.toc a.is-active::before { color: var(--accent); font-weight: 600; }

.rail__foot { margin-top: auto; display: grid; gap: 0.9rem; }
.rail__links {
  display: flex;
  flex-wrap: wrap;
  gap: 0.25rem 0.9rem;
  font-size: var(--fs-meta);
}
.rail__theme {
  justify-self: start;
  font-size: var(--fs-label);
  color: var(--ink-3);
  padding: 0.3rem 0;
}
.rail__theme:hover { color: var(--accent); }

/* ════════════ SECTIONS ════════════ */
section { margin-bottom: clamp(4rem, 9vh, 6rem); }

h2 {
  font-family: var(--serif);
  font-weight: 500;
  font-size: clamp(1.5rem, 2.6vw, 1.9rem);
  letter-spacing: -0.01em;
  line-height: 1.15;
  display: flex;
  align-items: baseline;
  gap: 1rem;
  padding-bottom: 0.7rem;
  border-bottom: 1px solid var(--ink);
  margin-bottom: 1.75rem;
}
.sec__n {
  font-family: var(--sans);
  font-weight: 450;
  font-size: var(--fs-label);
  letter-spacing: 0.06em;
  color: var(--accent);
  font-variant-numeric: tabular-nums;
}

h3.sub, h3.sys-group {
  font-family: var(--sans);
  font-weight: 600;
  font-size: var(--fs-label);
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--ink-3);
  margin: 2.75rem 0 1rem;
}

.section-note { color: var(--ink-3); font-size: var(--fs-meta); margin: -0.9rem 0 1.6rem; }
.prose { max-width: var(--measure); color: var(--ink-2); }

/* ════════════ 01 ABOUT ════════════ */
.hero {
  font-family: var(--serif);
  font-weight: 340;
  font-size: clamp(2.1rem, 4.4vw, 3.3rem);
  line-height: 1.12;
  letter-spacing: -0.015em;
  margin-bottom: 2.25rem;
  text-wrap: balance;
}
.hero em { font-style: italic; font-weight: 400; color: var(--accent); }

.bio { max-width: var(--measure); display: grid; gap: 1rem; }
.bio .lede {
  font-family: var(--serif);
  font-weight: 400;
  font-size: 1.22rem;
  line-height: 1.55;
  color: var(--ink);
}
.bio p { color: var(--ink-2); }
.bio em { font-style: italic; color: var(--ink); }

.meta-line {
  margin-top: 1.75rem;
  padding-top: 1rem;
  border-top: 1px solid var(--line);
  font-size: var(--fs-meta);
  color: var(--ink-3);
  max-width: var(--measure);
}

/* ════════════ 02 RECENT ════════════ */
.news { max-width: var(--measure); display: grid; }
.news li {
  display: grid;
  grid-template-columns: 3.6rem 1fr;
  gap: 1.1rem;
  padding: 0.7rem 0;
  border-bottom: 1px solid var(--line);
  font-size: var(--fs-body);
  color: var(--ink-2);
}
.news li:first-child { border-top: 1px solid var(--line); }
.news__date { color: var(--ink-3); font-size: var(--fs-meta); font-variant-numeric: tabular-nums; padding-top: 0.1rem; }
.news em { font-style: italic; color: var(--ink); }

/* ════════════ 03 RESEARCH ════════════ */
.statement {
  font-family: var(--serif);
  font-weight: 400;
  font-size: clamp(1.2rem, 2.2vw, 1.5rem);
  line-height: 1.45;
  letter-spacing: -0.005em;
  max-width: 56ch;
  color: var(--ink);
  padding-left: 1.4rem;
  border-left: 2px solid var(--accent);
  margin-bottom: 2.25rem;
}

.directions { max-width: var(--measure); counter-reset: dir; display: grid; }
.directions li {
  counter-increment: dir;
  display: grid;
  grid-template-columns: 3.6rem 1fr;
  gap: 1.1rem;
  padding: 1.1rem 0;
  border-bottom: 1px solid var(--line);
}
.directions li:first-child { border-top: 1px solid var(--line); }
.directions li::before {
  content: counter(dir, decimal-leading-zero);
  font-size: var(--fs-label);
  color: var(--accent);
  font-variant-numeric: tabular-nums;
  padding-top: 0.25rem;
}
.directions h3 {
  font-family: var(--serif);
  font-weight: 500;
  font-size: var(--fs-title);
  margin-bottom: 0.3rem;
}
/* number pseudo-element occupies column 1; keep the text in column 2 */
.directions h3, .directions p { grid-column: 2; }
.directions li::before { grid-row: 1; }
.directions p { color: var(--ink-2); font-size: var(--fs-body); }

/* ════════════ 04 PUBLICATIONS ════════════ */
.pubs { max-width: var(--measure); display: grid; }
.pubs > li {
  padding: 1.15rem 0;
  border-bottom: 1px solid var(--line);
}
.pubs > li:first-child { border-top: 1px solid var(--line); }
.pub__cite {
  font-size: var(--fs-head);
  color: var(--ink-2);
  padding-left: 1.6rem;
  text-indent: -1.6rem;     /* hanging indent, bibliography style */
}
.pub__cite strong { color: var(--ink); font-weight: 600; }
.pub__cite em { font-style: italic; }
.pub__status {
  font-size: var(--fs-label);
  letter-spacing: 0.04em;
  color: var(--accent);
  border: 1px solid color-mix(in srgb, var(--accent) 40%, transparent);
  border-radius: 2px;
  padding: 0.05rem 0.35rem;
  white-space: nowrap;
}
.pub__abs { font-size: var(--fs-meta); color: var(--ink-3); margin-top: 0.45rem; padding-left: 1.6rem; }

/* ════════════ 05 SYSTEMS ════════════ */
#systems { counter-reset: sys fig; }

/* figure — evidence. static poster by default; plays only on click */
.fig { max-width: var(--measure); margin-bottom: 2.25rem; counter-increment: fig; }
.fig video {
  display: block;
  width: 100%;
  height: auto;
  background: var(--bg-rail);
  border: 1px solid var(--line);
}
.fig figcaption {
  margin-top: 0.7rem;
  font-size: var(--fs-meta);
  line-height: 1.55;
  color: var(--ink-3);
  padding-left: 1.6rem;
  text-indent: -1.6rem;
}
.fig figcaption::before {
  content: "Fig. " counter(fig) "  ";
  color: var(--accent);
  font-variant-numeric: tabular-nums;
}
.fig figcaption em { font-style: italic; }

.sys { max-width: var(--measure); counter-increment: sys; }
.sys summary {
  display: flex;
  align-items: baseline;
  gap: 0.9rem;
  padding: 0.85rem 0;
  border-bottom: 1px solid var(--line);
  cursor: pointer;
  list-style: none;
}
.sys summary::-webkit-details-marker { display: none; }
.sys:first-of-type summary,
.sys-group + .sys summary { border-top: 1px solid var(--line); }

.sys summary::before {
  content: counter(sys, decimal-leading-zero);
  font-size: var(--fs-label);
  color: var(--ink-3);
  font-variant-numeric: tabular-nums;
  flex: none;
  width: 1.7rem;
}
.sys summary::after {
  content: "+";
  font-family: var(--serif);
  font-size: 1rem;
  color: var(--ink-3);
  flex: none;
}
.sys[open] summary::after { content: "×"; color: var(--accent); }
.sys[open] summary::before { color: var(--accent); }

.sys__title {
  font-family: var(--serif);
  font-weight: 500;
  font-size: var(--fs-title);
  color: var(--ink);
}
.sys summary:hover .sys__title { color: var(--accent); }

.sys__lead {
  flex: 1;
  min-width: 1.5rem;
  border-bottom: 1px dotted var(--line-2);
  transform: translateY(-0.3em);
}
.sys__year {
  font-size: var(--fs-meta);
  color: var(--ink-3);
  font-variant-numeric: tabular-nums;
  white-space: nowrap;
}

.sys__body {
  padding: 1.1rem 0 1.4rem 2.6rem;
  border-bottom: 1px solid var(--line);
}
.sys__body p { color: var(--ink-2); font-size: var(--fs-body); max-width: 62ch; }
.sys__body ul {
  margin: 0.85rem 0;
  display: grid;
  gap: 0.3rem;
  list-style: none;
}
.sys__body ul li {
  font-size: var(--fs-body);
  color: var(--ink-2);
}
.sys__methods { font-size: var(--fs-meta) !important; color: var(--ink-3) !important; }

/* secondary systems — present, but not competing with the flagship five */
.minor { max-width: var(--measure); display: grid; }
.minor li {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 0.5rem 1rem;
  align-items: baseline;
  padding: 0.7rem 0;
  border-bottom: 1px solid var(--line);
}
.minor li:first-child { border-top: 1px solid var(--line); }
.minor__title {
  font-family: var(--serif);
  font-weight: 500;
  font-size: var(--fs-head);
  color: var(--ink);
  line-height: 1.3;
}
.minor__desc { font-size: var(--fs-meta); color: var(--ink-3); margin-top: 0.15rem; }
.minor__year {
  font-size: var(--fs-meta);
  color: var(--ink-3);
  font-variant-numeric: tabular-nums;
  white-space: nowrap;
}

/* ════════════ 06 TALKS ════════════ */
.talks { max-width: var(--measure); display: grid; }
.talks li {
  display: grid;
  grid-template-columns: 3.6rem 1fr;
  gap: 1.1rem;
  padding: 1rem 0;
  border-bottom: 1px solid var(--line);
}
.talks li:first-child { border-top: 1px solid var(--line); }
.talks__year { color: var(--ink-3); font-size: var(--fs-meta); font-variant-numeric: tabular-nums; padding-top: 0.2rem; }
.talks__title { font-family: var(--serif); font-weight: 500; font-size: var(--fs-title); line-height: 1.35; }
.talks__venue { font-size: var(--fs-meta); color: var(--ink-3); margin-top: 0.25rem; }

/* ════════════ 07–08 CV LISTS ════════════ */
.cvlist { max-width: var(--measure); display: grid; }
.cvlist li {
  display: grid;
  grid-template-columns: 10rem 1fr;
  gap: 1.25rem;
  padding: 1rem 0;
  border-bottom: 1px solid var(--line);
}
.cvlist li:first-child { border-top: 1px solid var(--line); }
.cvlist__when { color: var(--ink-3); font-size: var(--fs-meta); font-variant-numeric: tabular-nums; padding-top: 0.2rem; }
.cvlist__head { font-size: var(--fs-head); color: var(--ink); font-weight: 500; }
.cvlist__org { font-weight: 400; color: var(--ink-2); }
.cvlist__note { font-size: var(--fs-meta); color: var(--ink-3); margin-top: 0.3rem; }

/* ════════════ 09 AWARDS / SKILLS ════════════ */
.plain { max-width: var(--measure); display: grid; }
.plain li {
  color: var(--ink-2);
  font-size: var(--fs-body);
  padding: 0.6rem 0 0.6rem 1.4rem;
  border-bottom: 1px solid var(--line);
  position: relative;
}
.plain li:first-child { border-top: 1px solid var(--line); }
.plain li::before {
  content: "·";
  position: absolute;
  left: 0.2rem;
  color: var(--accent);
  font-weight: 600;
}

.skills { max-width: var(--measure); display: grid; }
.skills > div {
  display: grid;
  grid-template-columns: 15rem 1fr;
  gap: 1.25rem;
  padding: 0.8rem 0;
  border-bottom: 1px solid var(--line);
}
.skills > div:first-of-type { border-top: 1px solid var(--line); }
.skills dt { font-weight: 500; font-size: var(--fs-body); color: var(--ink); }
.skills dd { font-size: var(--fs-meta); color: var(--ink-3); }

/* ════════════ 10 WRITING ════════════ */
.posts { max-width: var(--measure); display: grid; }
.posts li {
  display: flex;
  align-items: baseline;
  gap: 0.9rem;
  flex-wrap: wrap;
  padding: 0.65rem 0;
  border-bottom: 1px solid var(--line);
}
.posts li:first-child { border-top: 1px solid var(--line); }
.posts a { font-size: var(--fs-head); color: var(--ink); }
.posts a:hover { color: var(--accent); }
.posts__date { margin-left: auto; font-size: var(--fs-meta); color: var(--ink-3); font-variant-numeric: tabular-nums; }

/* ════════════ 11 CONTACT ════════════ */
.contact__mail { margin: 1.5rem 0; }
.contact__mail a {
  font-family: var(--serif);
  font-weight: 400;
  font-size: clamp(1.3rem, 3vw, 1.9rem);
  letter-spacing: -0.01em;
  color: var(--ink);
}
.contact__mail a:hover { color: var(--accent); }

/* ════════════ COLOPHON ════════════ */
.colophon {
  margin-top: 4rem;
  padding-top: 1.25rem;
  border-top: 1px solid var(--line);
  font-size: var(--fs-meta);
  color: var(--ink-3);
  display: grid;
  gap: 0.2rem;
}

/* ════════════ RESPONSIVE ════════════ */
@media (max-width: 940px) {
  .layout { grid-template-columns: 1fr; }
  .rail {
    position: static;
    max-height: none;
    border-right: 0;
    border-bottom: 1px solid var(--line);
    padding: clamp(2rem, 5vh, 3rem) 0 1.75rem;
    margin-right: 0;
    gap: 1.5rem;
  }
  .toc ol { grid-template-columns: 1fr 1fr; column-gap: 1.5rem; }
  .toc li:nth-child(2) a { border-top: 1px solid var(--line); } /* second column top edge */
  .rail__foot { margin-top: 0; }
  main { padding-top: 2.5rem; }
}

@media (max-width: 620px) {
  .toc ol { grid-template-columns: 1fr; }
  .toc li:nth-child(2) a { border-top: 0; }
  .cvlist li, .skills > div { grid-template-columns: 1fr; gap: 0.2rem; }
  .cvlist__when { padding-top: 0; }
  .news li, .talks li, .directions li { grid-template-columns: 2.9rem 1fr; gap: 0.8rem; }
  .sys__body { padding-left: 0; }
  .posts__date { margin-left: 0; }
  /* no room for a dotted leader once the title wraps */
  .sys__lead { display: none; }
  .sys__title { flex: 1; }
  .minor li { grid-template-columns: 1fr; }
  .minor__year { grid-row: 1; justify-self: start; }
}

/* ════════════ PRINT ════════════ */
@media print {
  .skip-link, .rail__theme { display: none; }
  body { border-top: 0; background: #fff; color: #000; font-size: 10.5pt; }
  .layout { display: block; max-width: none; padding: 0; }
  .rail { position: static; border: 0; padding: 0 0 1rem; }
  .toc { display: none; }
  a { color: #000; text-decoration: none; }
  .sys summary::after { content: ""; }
  .sys__body { padding-left: 1.7rem; }
  section { break-inside: avoid-page; margin-bottom: 1.6rem; }
  @page { margin: 1.6cm; }
}