/* =========================================================
   Andreas Kotsadam — academic homepage
   Single stylesheet. Plain CSS, no build step.
   ========================================================= */

:root {
  --ink:      #1c1c1e;   /* main text            */
  --muted:    #5c6066;   /* secondary text       */
  --accent:   #1a4d7a;   /* deep blue links      */
  --accent-2: #0f3a5e;   /* darker hover         */
  --line:     #e4e6ea;   /* hairlines            */
  --bg:       #ffffff;
  --bg-soft:  #f7f8fa;   /* alternating sections */
  --tag:      #eef2f7;   /* link-pill background */
  --maxw:     820px;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto,
               Helvetica, Arial, sans-serif;
  font-size: 17px;
  line-height: 1.6;
  color: var(--ink);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
}

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

.wrap { max-width: var(--maxw); margin: 0 auto; padding: 0 22px; }

/* ---------- top navigation ---------- */
nav.topbar {
  position: sticky; top: 0; z-index: 10;
  background: rgba(255,255,255,0.92);
  backdrop-filter: saturate(180%) blur(8px);
  border-bottom: 1px solid var(--line);
}
nav.topbar .wrap {
  display: flex; flex-wrap: wrap; align-items: center;
  gap: 4px 20px; padding-top: 12px; padding-bottom: 12px;
}
nav.topbar .brand { font-weight: 700; margin-right: auto; }
nav.topbar a { color: var(--muted); font-size: 15px; }
nav.topbar a:hover { color: var(--accent); text-decoration: none; }
nav.topbar a.brand { color: var(--ink); font-size: inherit; }
nav.topbar a.brand:hover { color: var(--accent); }
nav.topbar a.active { color: var(--accent); font-weight: 600; }

/* ---------- header / hero ---------- */
header.hero { padding: 48px 0 30px; }
header.hero .wrap {
  display: flex; gap: 32px; align-items: center; flex-wrap: wrap;
}
.hero-photo {
  width: 150px; height: 150px; border-radius: 50%;
  flex-shrink: 0; border: 1px solid var(--line);
  /* zoomed + panned onto the face (landscape source photo) */
  background-image: url('picture_kotsadam_2025.jpg');
  background-repeat: no-repeat;
  background-size: 210% auto;
  background-position: 38% 9%;
}
.hero-text h1 { margin: 0 0 6px; font-size: 34px; letter-spacing: -0.5px; }
.hero-text .roles { margin: 0 0 4px; color: var(--muted); font-size: 16px; }
.hero-text .roles strong { color: var(--ink); font-weight: 600; }

/* contact / profile link row */
.links { margin-top: 14px; display: flex; flex-wrap: wrap; gap: 8px; }
.links a {
  display: inline-flex; align-items: center; gap: 6px;
  font-size: 14px; padding: 5px 12px; border-radius: 20px;
  background: var(--tag); color: var(--accent);
}
.links a:hover { background: #e2e9f2; text-decoration: none; }

/* ---------- sections ---------- */
section { padding: 34px 0; border-top: 1px solid var(--line); }
section:nth-of-type(even) { background: var(--bg-soft); }
section h2 {
  font-size: 22px; margin: 0 0 18px;
  display: inline-block; padding-bottom: 4px;
  border-bottom: 3px solid var(--accent);
}
section > .wrap > p:first-of-type { margin-top: 0; }

.lead { font-size: 18px; color: var(--ink); }

/* ---------- publication / paper lists ---------- */
ol.pubs, ul.pubs { list-style: none; margin: 0; padding: 0; }
ol.pubs > li, ul.pubs > li {
  padding: 14px 0; border-bottom: 1px solid var(--line);
}
ol.pubs > li:last-child, ul.pubs > li:last-child { border-bottom: 0; }
.pub-title { font-weight: 600; }
.pub-meta  { color: var(--muted); font-size: 15.5px; }
.pub-meta em { font-style: italic; }
.status {
  display: inline-block; font-size: 12.5px; font-weight: 600;
  color: var(--accent-2); background: var(--tag);
  padding: 1px 8px; border-radius: 10px; margin-left: 6px;
  vertical-align: 1px;
}

/* small resource links under an entry */
.reslinks { margin-top: 5px; font-size: 14px; }
.reslinks a {
  display: inline-block; margin-right: 14px; white-space: nowrap;
}
.reslinks a::before { content: "\2192\00a0"; color: var(--muted); }

/* ---------- contact ---------- */
.contact-grid { display: grid; gap: 4px; }
.contact-grid div { padding: 2px 0; }
.contact-grid .label { color: var(--muted); display: inline-block; min-width: 96px; }

/* ---------- footer ---------- */
footer {
  border-top: 1px solid var(--line);
  padding: 26px 0 40px; color: var(--muted); font-size: 14px;
}

/* ---------- responsive ---------- */
@media (max-width: 560px) {
  body { font-size: 16px; }
  header.hero .wrap { gap: 20px; }
  .hero-photo { width: 110px; height: 110px; }
  .hero-text h1 { font-size: 27px; }
  nav.topbar .brand { width: 100%; margin-bottom: 4px; }
}