/* ===========================================================
   Femke De Backere — academic website
   Clean, lightweight stylesheet (no frameworks)
   =========================================================== */

:root {
  --blue: #1e64c8;        /* UGent blue */
  --blue-dark: #143f80;
  --blue-soft: #eef3fb;
  --ink: #1a1d23;
  --body: #3c4250;
  --muted: #6b7280;
  --line: #e6e8ec;
  --bg: #ffffff;
  --bg-alt: #f7f8fa;
  --max: 1080px;
  --radius: 12px;
  --shadow: 0 1px 3px rgba(16,24,40,.06), 0 8px 24px rgba(16,24,40,.05);
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  color: var(--body);
  background: var(--bg);
  line-height: 1.65;
  font-size: 17px;
  -webkit-font-smoothing: antialiased;
}

h1, h2, h3, h4 {
  color: var(--ink);
  line-height: 1.25;
  font-weight: 700;
  margin: 0 0 .5em;
}

h1 { font-size: 2.4rem; letter-spacing: -.02em; }
h2 { font-size: 1.7rem; letter-spacing: -.01em; }
h3 { font-size: 1.2rem; }

a { color: var(--blue); text-decoration: none; }
a:hover { color: var(--blue-dark); text-decoration: underline; }

p { margin: 0 0 1rem; }

.container { max-width: var(--max); margin: 0 auto; padding: 0 24px; }

/* ---------- Navigation ---------- */
.nav {
  position: sticky; top: 0; z-index: 50;
  background: rgba(255,255,255,.9);
  backdrop-filter: saturate(180%) blur(10px);
  border-bottom: 1px solid var(--line);
}
.nav-inner {
  max-width: var(--max); margin: 0 auto; padding: 0 24px;
  display: flex; align-items: center; justify-content: space-between;
  height: 64px;
}
.brand {
  font-weight: 700; color: var(--ink); font-size: 1.05rem;
  letter-spacing: -.01em; text-decoration: none;
}
.brand:hover { color: var(--blue); text-decoration: none; }
.nav-links { display: flex; gap: 4px; list-style: none; margin: 0; padding: 0; }
.nav-links a {
  display: block; padding: 8px 14px; border-radius: 8px;
  color: var(--body); font-size: .95rem; font-weight: 500;
  text-decoration: none; transition: background .15s, color .15s;
}
.nav-links a:hover { background: var(--blue-soft); color: var(--blue-dark); }
.nav-links a.active { color: var(--blue); background: var(--blue-soft); }

.nav-toggle {
  display: none; background: none; border: 0; cursor: pointer;
  font-size: 1.5rem; color: var(--ink); padding: 4px 8px;
}

/* ---------- Hero ---------- */
.hero { padding: 72px 0 48px; }
.hero-grid {
  display: grid; grid-template-columns: 1fr 280px; gap: 56px; align-items: center;
}
.hero h1 { margin-bottom: .25em; }
.hero .role { font-size: 1.15rem; color: var(--blue-dark); font-weight: 600; margin: 0 0 .35rem; }
.hero .sub { color: var(--muted); margin: 0 0 1.4rem; }
.hero-photo img {
  width: 100%; border-radius: var(--radius); box-shadow: var(--shadow);
  display: block;
}

.contact-list { list-style: none; padding: 0; margin: 1.2rem 0 0; display: flex; flex-wrap: wrap; gap: 10px; }
.contact-list a, .contact-list span {
  display: inline-flex; align-items: center; gap: 7px;
  padding: 7px 14px; border: 1px solid var(--line); border-radius: 999px;
  background: var(--bg); color: var(--body); font-size: .9rem; font-weight: 500;
  text-decoration: none; transition: border-color .15s, color .15s, background .15s;
}
.contact-list a:hover { border-color: var(--blue); color: var(--blue); background: var(--blue-soft); text-decoration: none; }

/* ---------- Sections ---------- */
section.block { padding: 40px 0; }
section.alt { background: var(--bg-alt); border-top: 1px solid var(--line); border-bottom: 1px solid var(--line); }
.section-head { margin-bottom: 1.6rem; }
.section-head h2 { margin-bottom: .25rem; }
.section-head .lead { color: var(--muted); margin: 0; }

/* Page banner (interior pages) */
.page-banner { background: var(--blue-soft); border-bottom: 1px solid var(--line); padding: 48px 0 40px; }
.page-banner h1 { margin: 0 0 .3rem; }
.page-banner p { color: var(--blue-dark); margin: 0; font-weight: 500; }

/* ---------- Cards / grids ---------- */
.cards { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; }
.cards.two { grid-template-columns: repeat(2, 1fr); }
.card {
  background: var(--bg); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 22px; box-shadow: var(--shadow);
}
.card h3 { margin-bottom: .4rem; }
.card p { margin: 0; color: var(--body); font-size: .96rem; }

/* Stats */
.stats { display: grid; grid-template-columns: repeat(4, 1fr); gap: 18px; }
.stat { text-align: center; padding: 18px 12px; border: 1px solid var(--line); border-radius: var(--radius); background: var(--bg); }
.stat .num { font-size: 2rem; font-weight: 800; color: var(--blue); line-height: 1; }
.stat .lbl { font-size: .85rem; color: var(--muted); margin-top: 6px; }

/* ---------- Timeline / lists ---------- */
.timeline { list-style: none; margin: 0; padding: 0; }
.timeline li {
  display: grid; grid-template-columns: 150px 1fr; gap: 20px;
  padding: 14px 0; border-top: 1px solid var(--line);
}
.timeline li:first-child { border-top: 0; }
.timeline .when { color: var(--blue-dark); font-weight: 600; font-size: .92rem; }
.timeline .what h4 { margin: 0 0 .15rem; font-size: 1.02rem; }
.timeline .what p { margin: 0; color: var(--muted); font-size: .94rem; }

/* Collapsible (native details) */
details.more { margin-top: 18px; }
details.more > summary {
  display: inline-flex; align-items: center; gap: 8px; cursor: pointer;
  font-weight: 600; color: var(--blue); font-size: .95rem;
  padding: 10px 20px; border: 1px solid var(--line); border-radius: 999px;
  background: var(--bg); list-style: none; width: max-content;
  transition: border-color .15s, background .15s, color .15s;
}
details.more > summary:hover { border-color: var(--blue); background: var(--blue-soft); }
details.more > summary::-webkit-details-marker { display: none; }
details.more > summary::after { content: "\25BE"; font-size: .85em; }
details.more[open] > summary::after { content: "\25B4"; }
details.more[open] > summary { margin-bottom: 14px; }

/* Simple list of items (service, etc.) */
.itemlist { list-style: none; margin: 0; padding: 0; }
.itemlist li {
  display: grid; grid-template-columns: 130px 1fr; gap: 18px;
  padding: 11px 0; border-top: 1px solid var(--line); font-size: .96rem;
}
.itemlist li:first-child { border-top: 0; }
.itemlist .yr { color: var(--muted); font-weight: 600; font-size: .9rem; }

/* Project entries */
.project { padding: 20px 0; border-top: 1px solid var(--line); }
.project:first-child { border-top: 0; }
.project .meta { color: var(--blue-dark); font-weight: 600; font-size: .9rem; margin-bottom: .25rem; }
.project h3 { margin-bottom: .35rem; }
.project .partners { color: var(--muted); font-size: .9rem; font-style: italic; margin-bottom: .5rem; }
.project p { font-size: .96rem; margin: 0; }

/* Publications */
.pub-group { margin-bottom: 36px; }
.pub-list { list-style: none; counter-reset: pub; margin: 0; padding: 0; }
.pub-list li {
  padding: 12px 0 12px 0; border-top: 1px solid var(--line);
  font-size: .95rem; line-height: 1.55;
}
.pub-list li:first-child { border-top: 0; }
.pub-list .year { color: var(--blue); font-weight: 700; }
.pub-list .venue { font-style: italic; color: var(--muted); }
.tag {
  display: inline-block; background: var(--blue-soft); color: var(--blue-dark);
  font-size: .72rem; font-weight: 700; padding: 2px 8px; border-radius: 999px;
  margin-left: 6px; vertical-align: middle; letter-spacing: .02em;
}

/* Theme chips */
.chips { display: flex; flex-wrap: wrap; gap: 10px; margin-top: 4px; }
.chip { background: var(--blue-soft); color: var(--blue-dark); border-radius: 999px; padding: 6px 16px; font-size: .9rem; font-weight: 600; }

/* Illustrated research pillars */
.pillars { display: grid; grid-template-columns: repeat(4, 1fr); gap: 22px; }
.pillar {
  background: var(--bg); border: 1px solid var(--line); border-radius: var(--radius);
  overflow: hidden; box-shadow: var(--shadow); display: flex; flex-direction: column;
}
.pillar .art { display: flex; align-items: flex-end; justify-content: center; height: 210px; padding-top: 18px; }
.pillar .art img { height: 192px; width: auto; display: block; }
.pillar .body { padding: 18px 18px 22px; border-top: 3px solid var(--accent, var(--blue)); flex: 1; }
.pillar h3 { margin: 0 0 .4rem; font-size: 1.08rem; color: var(--accent, var(--ink)); }
.pillar p { margin: 0; font-size: .92rem; color: var(--body); }

@media (max-width: 860px) { .pillars { grid-template-columns: repeat(2, 1fr); } }
@media (max-width: 480px) { .pillars { grid-template-columns: 1fr; } }

/* ---------- Footer ---------- */
.footer { background: var(--ink); color: #c7ccd6; padding: 40px 0; margin-top: 40px; }
.footer a { color: #fff; }
.footer-grid { display: flex; justify-content: space-between; flex-wrap: wrap; gap: 24px; }
.footer h4 { color: #fff; font-size: 1rem; margin-bottom: .5rem; }
.footer p { margin: 0 0 .35rem; font-size: .92rem; }
.footer .copyright { margin-top: 24px; padding-top: 16px; border-top: 1px solid #2c313c; font-size: .82rem; color: #8b919e; }
.footer-social a { display: inline-block; margin-right: 14px; font-size: .92rem; }

/* ---------- Responsive ---------- */
@media (max-width: 860px) {
  .hero-grid { grid-template-columns: 1fr; gap: 32px; }
  .hero-photo { order: -1; max-width: 240px; }
  .cards, .cards.two { grid-template-columns: 1fr; }
  .stats { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 680px) {
  body { font-size: 16px; }
  h1 { font-size: 1.95rem; }
  h2 { font-size: 1.45rem; }
  .hero { padding: 48px 0 32px; }
  .nav-toggle { display: block; }
  .nav-links {
    display: none; position: absolute; top: 64px; left: 0; right: 0;
    flex-direction: column; background: #fff; border-bottom: 1px solid var(--line);
    padding: 8px 16px 16px;
  }
  .nav-links.open { display: flex; }
  .timeline li, .itemlist li { grid-template-columns: 1fr; gap: 4px; }
  .timeline .when, .itemlist .yr { margin-bottom: 2px; }
}