/* =========================================================
   Manuela R. Collis — Personal Academic Site
   Modern minimal design with subtle Carnegie Red accents
   ========================================================= */

:root {
  /* Tartan-inspired palette (subtle) */
  --carnegie-red: #c41230;
  --carnegie-red-dark: #9a0e26;
  --carnegie-red-soft: #fdf2f4;

  /* Section accents (tartan family) */
  --tartan-green: #2f5234;
  --tartan-green-dark: #1f3922;
  --tartan-green-soft: #f1f5f1;
  --tartan-navy: #1f3a5f;
  --tartan-navy-dark: #142948;
  --tartan-navy-soft: #f0f3f8;

  /* Neutrals */
  --ink: #1a1a1a;
  --ink-2: #2c2c2c;
  --muted: #5a5a5a;
  --muted-2: #8a8a8a;
  --rule: #e6e6e6;
  --rule-soft: #f0f0f0;
  --bg: #ffffff;
  --bg-soft: #fafaf9;
  --header-bg: rgba(255, 255, 255, 0.92);

  /* Accent used for links — overridden in dark mode for legibility */
  --accent: var(--carnegie-red);
  --accent-dark: var(--carnegie-red-dark);

  /* Typography */
  --font-serif: "Source Serif 4", "Source Serif Pro", "Crimson Pro", Georgia, "Times New Roman", serif;
  --font-sans: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif;

  /* Layout */
  --max-w: 1100px;
  --content-w: 760px;
}

/* ---------- Dark theme ---------- */
[data-theme="dark"] {
  --ink: #e9e9ec;
  --ink-2: #c8c8cc;
  --muted: #9a9da4;
  --muted-2: #74777e;
  --rule: #2a2d34;
  --rule-soft: #1f2229;
  --bg: #0f1115;
  --bg-soft: #181b22;
  --header-bg: rgba(15, 17, 21, 0.85);

  /* Accents brightened so they still pop on dark surfaces */
  --carnegie-red: #ef4566;
  --carnegie-red-dark: #c41230;
  --carnegie-red-soft: #2a151a;
  --tartan-green: #6fa676;
  --tartan-green-dark: #4a8a55;
  --tartan-green-soft: #15201a;
  --tartan-navy: #7aa3d4;
  --tartan-navy-dark: #4d7eb8;
  --tartan-navy-soft: #141d2a;

  --accent: var(--carnegie-red);
  --accent-dark: var(--carnegie-red-dark);

  color-scheme: dark;
}

/* ---------- reset ---------- */
*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; scroll-padding-top: 80px; }
body {
  margin: 0;
  font-family: var(--font-sans);
  font-size: 17px;
  line-height: 1.65;
  color: var(--ink);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}
img { max-width: 100%; display: block; }
a {
  color: var(--carnegie-red);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: border-color 0.15s ease, color 0.15s ease;
}
a:hover { border-bottom-color: var(--carnegie-red); }
a:focus-visible { outline: 2px solid var(--carnegie-red); outline-offset: 3px; border-radius: 2px; }

h1, h2, h3, h4 {
  font-family: var(--font-serif);
  font-weight: 500;
  color: var(--ink);
  letter-spacing: -0.01em;
  line-height: 1.2;
  margin: 0 0 0.5em;
}
h1 { font-size: clamp(2rem, 4vw, 2.85rem); font-weight: 500; }
h2 { font-size: 1.55rem; }
h3 { font-size: 1.15rem; }
p { margin: 0 0 1.1em; }
small { color: var(--muted); }

/* ---------- header / nav ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: var(--header-bg);
  backdrop-filter: saturate(140%) blur(8px);
  -webkit-backdrop-filter: saturate(140%) blur(8px);
  border-bottom: 1px solid var(--rule);
}
.nav {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 18px 28px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}
.brand {
  font-family: var(--font-serif);
  font-size: 1.05rem;
  color: var(--ink);
  border-bottom: none;
  letter-spacing: 0.01em;
}
.brand .brand-mark {
  display: inline-block;
  width: 10px;
  height: 10px;
  background: var(--carnegie-red);
  margin-right: 10px;
  vertical-align: 1px;
  border-radius: 50%;   /* circle — reads cleaner than a rounded square */
}
.nav-links {
  display: flex;
  gap: 28px;
  list-style: none;
  margin: 0;
  padding: 0;
}
.nav-links a {
  color: var(--ink-2);
  font-size: 0.95rem;
  font-weight: 500;
  border-bottom: 1px solid transparent;
  padding-bottom: 2px;
}
.nav-links a:hover { color: var(--carnegie-red); border-bottom-color: var(--carnegie-red); }
.nav-links a.active { color: var(--carnegie-red); border-bottom-color: var(--carnegie-red); }

.nav-right {
  display: flex;
  align-items: center;
  gap: 20px;
}

/* ---------- Theme toggle (sun / moon) ---------- */
.theme-toggle {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  padding: 0;
  background: transparent;
  border: 1px solid var(--rule);
  border-radius: 999px;
  color: var(--ink-2);
  cursor: pointer;
  transition: color 0.15s ease, border-color 0.15s ease, background 0.15s ease;
}
.theme-toggle:hover {
  color: var(--carnegie-red);
  border-color: var(--carnegie-red);
  background: var(--carnegie-red-soft);
}
.theme-toggle:focus-visible {
  outline: 2px solid var(--carnegie-red);
  outline-offset: 2px;
}
.theme-toggle svg { width: 16px; height: 16px; }

/* Show sun in light mode, moon in dark mode. */
.theme-toggle .icon-moon { display: none; }
.theme-toggle .icon-sun  { display: block; }
[data-theme="dark"] .theme-toggle .icon-sun  { display: none; }
[data-theme="dark"] .theme-toggle .icon-moon { display: block; }

/* ---------- containers ---------- */
.container {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 0 28px;
}
.content-narrow {
  max-width: var(--content-w);
  margin-left: auto;
  margin-right: auto;
}

/* ---------- hero ---------- */
.hero {
  padding: 80px 0 56px;
  border-bottom: 1px solid var(--rule);
}
.hero-grid {
  display: grid;
  grid-template-columns: 1fr 1.4fr;
  gap: 64px;
  align-items: center;
}
.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-sans);
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--carnegie-red);
  margin-bottom: 20px;
}
.eyebrow::before {
  content: "";
  width: 28px;
  height: 1.5px;
  background: var(--carnegie-red);
}
.hero h1 {
  margin-top: 0;
  margin-bottom: 18px;
}
.hero .lede {
  font-size: 1.12rem;
  color: var(--muted);
  margin: 0 0 28px;
  max-width: 50ch;
}
.hero-cta {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
}
.btn {
  display: inline-block;
  padding: 11px 22px;
  font-family: inherit;          /* button defaults to system font otherwise */
  font-size: 0.92rem;
  font-weight: 500;
  line-height: 1.4;              /* explicit, so <a> and <button> match */
  border-radius: 4px;
  border: 1.5px solid var(--ink);
  color: var(--ink);
  background: transparent;
  cursor: pointer;
  text-align: center;
  vertical-align: middle;
  -webkit-appearance: none;      /* strip iOS/Android native styling */
  appearance: none;
  transition: all 0.15s ease;
}
.btn:hover { background: var(--ink); color: #fff; border-color: var(--ink); }
.btn-primary {
  background: var(--carnegie-red);
  border-color: var(--carnegie-red);
  color: #fff;
}
.btn-primary:hover { background: var(--carnegie-red-dark); border-color: var(--carnegie-red-dark); color: #fff; }
.btn-sm {
  padding: 7px 14px;
  font-size: 0.85rem;
  line-height: 1.4;
  border-width: 1px;
  border-color: var(--rule);
  color: var(--ink-2);
  background: var(--bg-soft);
}
.btn-sm:hover { background: var(--carnegie-red-soft); color: var(--carnegie-red); border-color: var(--carnegie-red); }

/* BibTeX-copy button — brief "Copied!" confirmation state. */
.btn-bibtex.btn-copied,
.btn-bibtex.btn-copied:hover {
  background: var(--carnegie-red);
  color: #fff;
  border-color: var(--carnegie-red);
}

.profile-links {
  list-style: none;
  margin: 28px 0 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}
.profile-links a {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 8px 14px;
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--ink-2);
  background: var(--bg);
  border: 1px solid var(--rule);
  border-radius: 999px;
  border-bottom: 1px solid var(--rule);
  transition: all 0.15s ease;
}
.profile-links a:hover {
  color: var(--carnegie-red);
  border-color: var(--carnegie-red);
  background: var(--carnegie-red-soft);
}
.profile-links svg {
  width: 16px;
  height: 16px;
  flex-shrink: 0;
}
.profile-links-lg a {
  padding: 12px 20px;
  font-size: 1rem;
  border-radius: 999px;
}
.profile-links-lg svg {
  width: 18px;
  height: 18px;
}

/* ---------- Home page CTAs into Research / CV ---------- */
.explore {
  padding-top: 24px;
}
.cta-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 18px;
}
.cta-card {
  display: grid;
  grid-template-columns: 1fr auto;
  align-items: center;
  gap: 12px 18px;
  padding: 22px 24px;
  border: 1px solid var(--rule);
  border-radius: 6px;
  background: var(--bg);
  color: var(--ink);
  border-bottom: 1px solid var(--rule);
  transition: border-color 0.15s ease, transform 0.15s ease, box-shadow 0.15s ease;
}
.cta-card:hover {
  border-color: var(--carnegie-red);
  transform: translateY(-1px);
  box-shadow: 0 4px 14px rgba(196, 18, 48, 0.08);
}
.cta-card .cta-label {
  grid-column: 1;
  font-family: var(--font-serif);
  font-size: 1.25rem;
  font-weight: 500;
  color: var(--ink);
  line-height: 1.2;
}
.cta-card .cta-desc {
  grid-column: 1;
  font-size: 0.92rem;
  color: var(--muted);
  line-height: 1.45;
}
.cta-card .cta-arrow {
  grid-column: 2;
  grid-row: 1 / span 2;
  font-size: 1.4rem;
  color: var(--carnegie-red);
  transition: transform 0.15s ease;
}
.cta-card:hover .cta-arrow {
  transform: translateX(3px);
}

.portrait {
  position: relative;
  aspect-ratio: 4 / 5;
  width: 100%;
  max-width: 360px;
  margin-left: auto;
  background: var(--bg-soft);
  overflow: hidden;
  border-radius: 2px;
}
.portrait img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  filter: contrast(1.02);
  display: block;
}

/* ---------- sections ---------- */
section {
  padding: 64px 0;
  border-bottom: 1px solid var(--rule-soft);
}
section:last-of-type { border-bottom: none; }
.section-title {
  font-family: var(--font-serif);
  font-size: 0.9rem;
  font-weight: 600;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--carnegie-red);
  margin-bottom: 28px;
}
.prose p {
  font-size: 1.04rem;
  line-height: 1.78;
  color: var(--ink-2);
  margin-bottom: 1.3em;
}
.prose p:last-child { margin-bottom: 0; }

/* ---------- research items ---------- */
.research-list {
  display: flex;
  flex-direction: column;
  gap: 44px;
}
.paper {
  position: relative;
  padding-left: 22px;
  border-left: 2px solid var(--rule);
  transition: border-color 0.2s ease;
}
.paper:hover { border-left-color: var(--carnegie-red); }
.paper:hover .paper-title { color: var(--carnegie-red); }
.paper-title {
  font-family: var(--font-serif);
  font-size: 1.25rem;
  font-weight: 500;
  color: var(--ink);
  margin: 0 0 6px;
  transition: color 0.2s ease;
  line-height: 1.35;
}
.paper-meta {
  font-size: 0.92rem;
  color: var(--muted);
  margin-bottom: 4px;
}
.paper-meta em { color: var(--ink-2); font-style: italic; }
.paper-coauthors { font-size: 0.92rem; color: var(--muted); margin-bottom: 14px; }
.paper-coauthors a { color: var(--ink-2); border-bottom: 1px dotted var(--muted-2); }
.paper-coauthors a:hover { color: var(--carnegie-red); border-bottom-color: var(--carnegie-red); }
.paper-abstract {
  font-size: 0.96rem;
  line-height: 1.7;
  color: var(--ink-2);
  margin: 10px 0 14px;
}
.paper-abstract .abs-label {
  display: inline-block;
  font-style: italic;
  color: var(--muted);
  margin-right: 6px;
  font-weight: 500;
}
.paper-links {
  display: flex;
  align-items: center;     /* don't stretch buttons to row height */
  gap: 8px;
  flex-wrap: wrap;
  margin-top: 14px;
}
.paper-note {
  font-style: italic;
  font-size: 0.92rem;
  color: var(--muted);
  margin-top: 10px;
}
.tag {
  display: inline-block;
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  padding: 3px 9px;
  border-radius: 3px;
  margin-left: 8px;
  vertical-align: 3px;
  background: var(--carnegie-red-soft);
  color: var(--carnegie-red);
}
.tag.muted { background: var(--rule-soft); color: var(--muted); }

/* ---------- tartan section accents (research page) ---------- */
/* Each tartan section sets local accent variables; the rules below
   apply across all three by reading var(--section-accent). */
.accent-red {
  --section-accent: var(--carnegie-red);
  --section-accent-soft: var(--carnegie-red-soft);
  --section-accent-dark: var(--carnegie-red-dark);
}
.accent-green {
  --section-accent: var(--tartan-green);
  --section-accent-soft: var(--tartan-green-soft);
  --section-accent-dark: var(--tartan-green-dark);
}
.accent-navy {
  --section-accent: var(--tartan-navy);
  --section-accent-soft: var(--tartan-navy-soft);
  --section-accent-dark: var(--tartan-navy-dark);
}

/* Generic accent-section styling, driven by --section-accent above. */
.accent-red .section-title,
.accent-green .section-title,
.accent-navy .section-title { color: var(--section-accent); }

.accent-red .paper:hover,
.accent-green .paper:hover,
.accent-navy .paper:hover { border-left-color: var(--section-accent); }

.accent-red .paper:hover .paper-title,
.accent-green .paper:hover .paper-title,
.accent-navy .paper:hover .paper-title { color: var(--section-accent); }

.accent-red .tag:not(.muted),
.accent-green .tag:not(.muted),
.accent-navy .tag:not(.muted) {
  background: var(--section-accent-soft);
  color: var(--section-accent);
}

.accent-red .paper-coauthors a:hover,
.accent-green .paper-coauthors a:hover,
.accent-navy .paper-coauthors a:hover,
.accent-red .paper-title a:hover,
.accent-green .paper-title a:hover,
.accent-navy .paper-title a:hover { color: var(--section-accent); }

/* PAPER BUTTONS — neutral by default; color up only when the visitor
   hovers the paper card; fill in when they hover an individual button. */
.accent-red  .paper:hover .btn-sm,
.accent-green .paper:hover .btn-sm,
.accent-navy .paper:hover .btn-sm {
  background: var(--section-accent-soft);
  color: var(--section-accent);
  border-color: var(--section-accent);
}
.accent-red  .paper .btn-sm:hover,
.accent-green .paper .btn-sm:hover,
.accent-navy .paper .btn-sm:hover {
  background: var(--section-accent);
  color: #fff;
  border-color: var(--section-accent);
}

/* "Copied!" confirmation also picks up the section accent. */
.accent-red  .paper .btn-bibtex.btn-copied,
.accent-green .paper .btn-bibtex.btn-copied,
.accent-navy .paper .btn-bibtex.btn-copied,
.accent-red  .paper .btn-bibtex.btn-copied:hover,
.accent-green .paper .btn-bibtex.btn-copied:hover,
.accent-navy .paper .btn-bibtex.btn-copied:hover {
  background: var(--section-accent-dark);
  color: #fff;
  border-color: var(--section-accent-dark);
}

/* ---------- subsection / page intro ---------- */
.page-intro {
  padding: 80px 0 36px;
  border-bottom: 1px solid var(--rule);
}
.page-intro h1 { margin-bottom: 14px; }
.page-intro p { color: var(--muted); font-size: 1.05rem; max-width: 60ch; }

/* ---------- CV viewer ---------- */
.cv-actions {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
  margin-bottom: 28px;
}
.cv-pages {
  display: flex;
  flex-direction: column;
  gap: 18px;
  max-width: 880px;
  margin: 0 auto;
}
.cv-pages img {
  width: 100%;
  height: auto;
  display: block;
  border: 1px solid var(--rule);
  border-radius: 4px;
  box-shadow: 0 1px 2px rgba(0,0,0,0.04), 0 4px 18px rgba(0,0,0,0.05);
  background: #fff;
}
[data-theme="dark"] .cv-pages img {
  /* CV scans are white-paper images. On a dark page, a slim light border
     and stronger shadow lifts them visually. */
  border-color: rgba(255, 255, 255, 0.12);
  box-shadow: 0 2px 6px rgba(0,0,0,0.5), 0 12px 32px rgba(0,0,0,0.4);
}

/* ---------- contact / footer ---------- */
.contact-block {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 24px 36px;
  margin-top: 16px;
}
.contact-item {
  position: relative;
  padding-left: 14px;
}
.contact-item::before {
  content: "";
  position: absolute;
  left: 0;
  top: 4px;
  bottom: 4px;
  width: 2px;
  background: var(--rule);
}
.contact-item .label {
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--muted-2);
  margin-bottom: 4px;
}
.contact-item .value { font-size: 1rem; color: var(--ink-2); }
.contact-item:nth-child(3n+1)::before { background: var(--carnegie-red); }
.contact-item:nth-child(3n+2)::before { background: var(--tartan-green); }
.contact-item:nth-child(3n+3)::before { background: var(--tartan-navy); }
.contact-item:nth-child(3n+1) .label { color: var(--carnegie-red); }
.contact-item:nth-child(3n+2) .label { color: var(--tartan-green); }
.contact-item:nth-child(3n+3) .label { color: var(--tartan-navy); }

.site-footer {
  border-top: 1px solid var(--rule);
  padding: 36px 0;
  margin-top: 0;
  background: var(--bg-soft);
}
.site-footer .footer-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 12px;
  font-size: 0.88rem;
  color: var(--muted);
}
.site-footer a { color: var(--muted); border-bottom: 1px dotted var(--muted-2); }
.site-footer a:hover { color: var(--carnegie-red); border-bottom-color: var(--carnegie-red); }

/* ---------- mobile ---------- */
@media (max-width: 820px) {
  body { font-size: 16px; }
  .nav { padding: 14px 20px; gap: 12px; }
  .nav-links { gap: 18px; }
  .container { padding: 0 20px; }
  .hero { padding: 56px 0 40px; }
  .hero-grid {
    grid-template-columns: 1fr;
    gap: 36px;
  }
  .portrait {
    max-width: 260px;
    margin: 0 auto;
  }
  section { padding: 48px 0; }
  .contact-block { grid-template-columns: 1fr; }
  .cv-frame { height: 70vh; }
}

@media (max-width: 480px) {
  .nav { flex-direction: column; align-items: flex-start; }
  .nav-links { gap: 16px; flex-wrap: wrap; }
  .brand { font-size: 0.98rem; }
}