/* ============================================================
   R.W. van den Broek — research portfolio · v2
   Editorial evolution of the paper-and-ink design.
   ============================================================ */

:root {
  --paper:      #eff1ee;
  --raised:     #f7f8f6;
  --ink:        #23272b;
  --ink-soft:   #545b62;
  --ink-faint:  #868d94;
  --accent:     #7a3b2e;   /* burnt sienna */
  --accent-soft:#a05a48;
  --rule:       #d8dcd6;
  --rule-firm:  #c2c8bf;
  --shadow:     rgba(28, 26, 23, 0.09);

  --serif: "EB Garamond", "Cormorant Garamond", Georgia, "Times New Roman", serif;
  --sans:  "Inter", "Segoe UI", system-ui, sans-serif;
  --measure: 36em;
  --gutter: 11rem;

  color-scheme: light;
}

/* dark — system default, unless the reader forced light */
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --paper:      #15181a;
    --raised:     #1d2124;
    --ink:        #e4e7e2;
    --ink-soft:   #a4aca9;
    --ink-faint:  #727b79;
    --accent:     #d88b78;
    --accent-soft:#b96e5b;
    --rule:       #2b3033;
    --rule-firm:  #3c4246;
    --shadow:     rgba(0, 0, 0, 0.4);
    color-scheme: dark;
  }
}
/* dark — explicitly chosen */
:root[data-theme="dark"] {
  --paper:      #15181a;
  --raised:     #1d2124;
  --ink:        #e4e7e2;
  --ink-soft:   #a4aca9;
  --ink-faint:  #727b79;
  --accent:     #d88b78;
  --accent-soft:#b96e5b;
  --rule:       #2b3033;
  --rule-firm:  #3c4246;
  --shadow:     rgba(0, 0, 0, 0.4);
  color-scheme: dark;
}

* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }
@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } }

body {
  font-family: var(--serif);
  background: var(--paper);
  color: var(--ink);
  font-size: 1.09rem;
  line-height: 1.64;
  font-weight: 400;
  -webkit-font-smoothing: antialiased;
  transition: background 0.4s ease, color 0.4s ease;
}

img { max-width: 100%; }
[hidden] { display: none !important; }

.container {
  max-width: 60rem;
  margin-inline: auto;
  padding-inline: max(1.4rem, 5vw);
}

/* anchored targets clear the sticky header */
section, .part-divider, [id] { scroll-margin-top: 5.5rem; }

/* skip link — visible only on keyboard focus */
.skip-link {
  position: absolute;
  left: 0.75rem; top: -3rem;
  z-index: 40;
  font-family: var(--sans); font-size: 0.8rem;
  background: var(--accent); color: #fff;
  padding: 0.5rem 0.9rem; border-radius: 4px;
  text-decoration: none;
  transition: top 0.15s ease;
}
.skip-link:focus { top: 0.75rem; }

/* ---------- header ---------- */

header.top {
  position: sticky;
  top: 0;
  z-index: 20;
  background: color-mix(in srgb, var(--paper) 86%, transparent);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--rule);
}
.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem 2rem;
  padding: 1rem 0;
}
.wordmark {
  font-family: var(--sans);
  font-size: 0.98rem;
  letter-spacing: 0.05em;
  font-weight: 500;
  color: var(--ink);
  text-decoration: none;
  white-space: nowrap;
}
nav.primary { display: flex; gap: 1.5rem; flex-wrap: wrap; }
nav.primary a {
  font-family: var(--sans);
  font-size: 0.76rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--ink-soft);
  text-decoration: none;
  padding-block: 0.2rem;
  border-bottom: 1.5px solid transparent;
  transition: color 0.15s ease, border-color 0.15s ease;
}
nav.primary a:hover { color: var(--accent); }
nav.primary a.active { color: var(--ink); border-bottom-color: var(--accent); }

.theme-toggle {
  flex: 0 0 auto;
  width: 2.1rem; height: 2.1rem;
  display: grid; place-items: center;
  border: 1px solid var(--rule-firm);
  border-radius: 50%;
  background: transparent;
  color: var(--ink-soft);
  cursor: pointer;
  transition: color 0.15s ease, border-color 0.15s ease;
}
.theme-toggle:hover { color: var(--accent); border-color: var(--accent); }
.theme-toggle:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }
.theme-toggle svg { width: 1.05rem; height: 1.05rem; }
.theme-toggle .moon { display: none; }
:root[data-theme="dark"] .theme-toggle .sun,
:root:not([data-theme="light"]) .theme-toggle .sun { display: none; }
:root[data-theme="dark"] .theme-toggle .moon,
:root:not([data-theme="light"]) .theme-toggle .moon { display: block; }
@media (prefers-color-scheme: light) {
  :root:not([data-theme="dark"]) .theme-toggle .sun { display: block; }
  :root:not([data-theme="dark"]) .theme-toggle .moon { display: none; }
}

/* ---------- hero ---------- */

.hero {
  display: grid;
  grid-template-columns: 1fr auto;
  align-items: center;
  gap: 2.6rem;
  padding: clamp(3rem, 8vh, 5.5rem) 0 clamp(2.5rem, 6vh, 4rem);
}
.hero-eyebrow {
  font-family: var(--sans);
  font-size: 0.78rem;
  letter-spacing: 0.13em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 1.1rem;
}
.hero h1 {
  font-size: clamp(2.4rem, 6.5vw, 3.7rem);
  font-weight: 500;
  line-height: 1.08;
  letter-spacing: -0.018em;
}
.hero .lede {
  margin-top: 1.5rem;
  font-size: clamp(1.2rem, 2.6vw, 1.4rem);
  font-style: italic;
  line-height: 1.45;
  color: var(--ink-soft);
  max-width: 30em;
  text-wrap: balance;
}
.hero-portrait {
  flex: 0 0 auto;
  width: 190px; height: 250px;
  object-fit: cover;
  border-radius: 5px;
  border: 1px solid var(--rule-firm);
  box-shadow: 0 6px 26px var(--shadow);
}
@media (max-width: 640px) {
  .hero { grid-template-columns: 1fr; gap: 1.6rem; }
  .hero-portrait { width: 148px; height: 195px; order: -1; }
}

/* ---------- editorial sections ---------- */

section { padding-block: clamp(2.8rem, 7vh, 4.6rem); border-top: 1px solid var(--rule); }

.row { display: grid; gap: 1rem; }
@media (min-width: 60rem) {
  .row { grid-template-columns: var(--gutter) minmax(0, 1fr); gap: 3rem; }
}
.eyebrow {
  font-family: var(--sans);
  font-size: 0.72rem;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--ink-faint);
  padding-top: 0.35rem;
}
.body-col { max-width: var(--measure); }
.prose p + p { margin-top: 1rem; }
.prose { color: var(--ink-soft); }
.prose strong { color: var(--ink); font-weight: 600; }
.prose em { color: var(--ink); }

h2.section-title {
  font-size: 1.6rem;
  font-weight: 500;
  letter-spacing: -0.01em;
  margin-bottom: 1.1rem;
}

/* ---------- work part-divider ---------- */

.part-divider {
  text-align: center;
  padding-block: clamp(2.6rem, 7vh, 4.2rem) 0;
}
.part-divider h2 {
  font-family: var(--sans);
  font-size: clamp(1.5rem, 4vw, 2.1rem);
  font-weight: 500;
  letter-spacing: 0.01em;
  color: var(--accent);
}
.part-divider .sub {
  font-family: var(--sans);
  font-size: 0.74rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--ink-faint);
  margin-top: 0.6rem;
}

/* ---------- domain groups (collapsible) ---------- */

.group + .group { margin-top: 1.4rem; }
details.fold > summary {
  cursor: pointer;
  list-style: none;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  font-family: var(--sans);
  font-size: 0.72rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--ink-faint);
  padding-bottom: 0.7rem;
  border-bottom: 1px solid var(--rule-firm);
  transition: color 0.15s ease;
}
details.fold > summary::-webkit-details-marker { display: none; }
details.fold > summary::marker { content: ""; }
details.fold > summary:hover { color: var(--accent); }
details.fold > summary:focus-visible { outline: 2px solid var(--accent); outline-offset: 3px; }
.chevron {
  width: 0.5rem; height: 0.5rem;
  border-right: 1.5px solid currentColor;
  border-bottom: 1.5px solid currentColor;
  transform: rotate(45deg) translateY(-0.12rem);
  transition: transform 0.2s ease;
}
details.fold[open] > summary .chevron { transform: rotate(-135deg); }

.domains {
  margin-top: 1.4rem;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(12rem, 1fr));
  gap: 1.3rem 2rem;
}
details.fold:not([open]) .domains,
details.fold:not([open]) .group-note,
details.fold:not([open]) .edu-list { display: none; }
.group-note {
  margin-top: 0.9rem;
  font-size: 0.96rem;
  font-style: italic;
  line-height: 1.55;
  color: var(--ink-faint);
  max-width: 38em;
}
.domain h3 {
  font-family: var(--sans);
  font-size: 0.76rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--accent);
  font-weight: 500;
}
.domain p { margin-top: 0.4rem; font-size: 0.98rem; line-height: 1.5; color: var(--ink-soft); }

/* education */
.edu-list { margin-top: 1rem; list-style: none; display: grid; gap: 0.7rem; }
.edu-list li {
  display: flex; justify-content: space-between; align-items: baseline;
  gap: 1rem; flex-wrap: wrap;
  padding-bottom: 0.7rem; border-bottom: 1px solid var(--rule);
}
.edu-degree { color: var(--ink); }
.edu-inst { font-family: var(--sans); font-size: 0.82rem; color: var(--ink-faint); }

/* ---------- paper accordion ---------- */

.accordion { border-top: 1px solid var(--rule); margin-top: 1.4rem; }
details.paper { border-bottom: 1px solid var(--rule); }
details.paper > summary {
  cursor: pointer;
  list-style: none;
  padding: 1.35rem 0;
}
details.paper > summary::-webkit-details-marker { display: none; }
details.paper > summary::marker { content: ""; }
details.paper > summary:focus-visible { outline: 2px solid var(--accent); outline-offset: 3px; }
.summary-inner {
  display: grid;
  grid-template-columns: 2.6rem 1fr auto auto;
  align-items: baseline;
  gap: 0.4rem 1rem;
}
.paper-num {
  font-family: var(--sans);
  font-size: 1.05rem;
  font-weight: 500;
  color: var(--rule-firm);
  font-variant-numeric: lining-nums;
}
details.paper[open] .paper-num { color: var(--accent-soft); }
.paper-title { font-size: 1.24rem; font-weight: 600; line-height: 1.32; transition: color 0.15s ease; }
details.paper > summary:hover .paper-title { color: var(--accent); }
.paper-teaser { display: block; margin-top: 0.3rem; font-size: 0.98rem; line-height: 1.5; color: var(--ink-soft); max-width: 34em; }
details.paper[open] .paper-teaser { display: none; }

.status-tag {
  font-family: var(--sans);
  font-size: 0.62rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--accent);
  border: 1px solid var(--accent-soft);
  border-radius: 99px;
  padding: 0.16rem 0.6rem;
  white-space: nowrap;
  align-self: center;
}
.status-tag.planned { color: var(--ink-faint); border-color: var(--rule-firm); }

.paper-body { padding: 0 0 1.8rem 3.6rem; max-width: var(--measure); color: var(--ink-soft); }
.paper-body p + p { margin-top: 0.9rem; }
.paper-sub { font-style: italic; color: var(--ink); font-size: 1.1rem; margin-bottom: 0.5rem; }
.paper-body em { color: var(--ink); font-style: italic; }

.plain {
  color: var(--ink);
  border-left: 2px solid var(--accent-soft);
  padding-left: 1rem;
  margin-bottom: 1.4rem;
}
.plain-label {
  display: block;
  font-family: var(--sans);
  font-size: 0.64rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 0.4rem;
}
.keywords { margin-top: 1.3rem; display: flex; flex-wrap: wrap; gap: 0.5rem; }
.keywords span {
  font-family: var(--sans); font-size: 0.7rem;
  color: var(--ink-faint);
  border: 1px solid var(--rule); border-radius: 99px;
  padding: 0.25rem 0.72rem;
}
.pub-actions { margin-top: 1.6rem; }
a.text-link {
  color: var(--accent); text-decoration: none;
  font-family: var(--sans); font-size: 0.85rem; letter-spacing: 0.02em;
  border-bottom: 1px solid transparent; transition: border-color 0.15s ease;
}
a.text-link:hover { border-bottom-color: var(--accent); }
.paper-status-note {
  font-family: var(--sans); font-size: 0.78rem; letter-spacing: 0.05em;
  color: var(--ink-faint); margin-top: 1rem;
}
@media (max-width: 600px) {
  .summary-inner {
    grid-template-columns: 1.8rem 1fr auto;
    grid-template-areas: "num heading chev" ". tag .";
    gap: 0.6rem;
  }
  .paper-num { grid-area: num; }
  .paper-heading { grid-area: heading; }
  .status-tag { grid-area: tag; justify-self: start; margin-top: 0.5rem; }
  .chevron { grid-area: chev; align-self: center; }
  .paper-title { font-size: 1.08rem; }
  .paper-body { padding-left: 2.5rem; }
}

/* ---------- contact ---------- */

.contact-list { list-style: none; display: grid; gap: 0.85rem; }
.contact-list li { display: grid; grid-template-columns: 8rem 1fr; gap: 1rem; align-items: baseline; }
.contact-list .label { font-family: var(--sans); font-size: 0.7rem; letter-spacing: 0.13em; text-transform: uppercase; color: var(--ink-faint); }
.contact-value { display: flex; align-items: center; gap: 0.6rem; flex-wrap: wrap; }
.contact-list a.email,
.contact-list code {
  font-family: var(--sans); font-size: 0.95rem;
  color: var(--ink); text-decoration: none;
  background: var(--raised); border: 1px solid var(--rule-firm);
  border-radius: 4px; padding: 0.3rem 0.55rem;
}
.contact-list a.email { transition: color 0.15s ease, border-color 0.15s ease; }
.contact-list a.email:hover { color: var(--accent); border-color: var(--accent); }
.copy-btn {
  font-family: var(--sans); font-size: 0.64rem; letter-spacing: 0.08em; text-transform: uppercase;
  color: var(--ink-faint); background: transparent;
  border: 1px solid var(--rule-firm); border-radius: 4px;
  padding: 0.3rem 0.55rem; cursor: pointer;
  transition: color 0.15s ease, border-color 0.15s ease;
}
.copy-btn:hover { color: var(--accent); border-color: var(--accent); }
.copy-btn:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }
@media (max-width: 560px) { .contact-list li { grid-template-columns: 1fr; gap: 0.35rem; } }

/* ---------- footer ---------- */

footer {
  border-top: 1px solid var(--rule-firm);
  padding-block: 2.5rem 3.5rem;
  font-family: var(--sans); font-size: 0.78rem; color: var(--ink-faint);
  display: flex; justify-content: space-between; flex-wrap: wrap; gap: 0.5rem 1.5rem;
}
footer a { color: var(--ink-soft); text-decoration: none; }
footer a:hover { color: var(--accent); }

/* ---------- paper detail pages ---------- */

.paper-page { padding-block: clamp(2.5rem, 7vh, 4rem); max-width: 44rem; }
.back-link {
  font-family: var(--sans); font-size: 0.78rem; letter-spacing: 0.08em;
  text-transform: uppercase; color: var(--ink-faint); text-decoration: none;
}
.back-link:hover { color: var(--accent); }
.paper-meta {
  font-family: var(--sans); font-size: 0.74rem; letter-spacing: 0.12em;
  text-transform: uppercase; color: var(--accent); margin-bottom: 1.1rem;
}
.paper-page h1 { font-size: clamp(1.9rem, 5vw, 2.7rem); font-weight: 500; line-height: 1.16; letter-spacing: -0.015em; }
.paper-subtitle { font-size: 1.35rem; font-style: italic; color: var(--ink-soft); margin-top: 0.4rem; }
.paper-author { margin-top: 1.3rem; color: var(--ink); }
.abstract-block { margin-top: 2.4rem; border-top: 1px solid var(--rule); padding-top: 1.9rem; }
.abstract-block h2 {
  font-family: var(--sans); font-size: 0.76rem; letter-spacing: 0.16em;
  text-transform: uppercase; color: var(--ink-faint); font-weight: 500; margin-bottom: 1.1rem;
}
.abstract-block p { color: var(--ink-soft); }
.abstract-block p + p { margin-top: 1rem; }
.toc { margin: 0; padding-left: 1.4rem; color: var(--ink-soft); }
.toc li { margin-bottom: 0.35rem; }
.toc li::marker { color: var(--rule-firm); }

/* ---------- scroll reveal ---------- */

.reveal { opacity: 0; transform: translateY(14px); transition: opacity 0.6s ease, transform 0.6s ease; }
.reveal.in { opacity: 1; transform: none; }
@media (prefers-reduced-motion: reduce) {
  .reveal { opacity: 1; transform: none; transition: none; }
}

/* ---------- print (clean CV) ---------- */

@media print {
  header.top, .theme-toggle, nav.primary, .chevron { display: none !important; }
  body { background: #fff; color: #000; font-size: 11pt; }
  section { border: 0; padding-block: 0.6rem; }
  details { break-inside: avoid; }
  details:not([open]) > summary ~ * { display: revert !important; }
  .paper-teaser { display: none !important; }
  details.fold:not([open]) .domains,
  details.fold:not([open]) .edu-list { display: grid !important; }
  a { color: #000; text-decoration: none; }
  .reveal { opacity: 1 !important; transform: none !important; }
}