/* Jiyoon Kim — personal academic site */

:root {
  --text: #1f1f1f;
  --muted: #595959;
  --accent: #4a6491;
  --heading: #2e4a76;
  --rule: #e3e3e3;
  --bg: #ffffff;
  --max-width: 880px;
  --serif: "Iowan Old Style", "Palatino Linotype", Palatino, Georgia, serif;
  --sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "Helvetica Neue", Arial, sans-serif;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: var(--serif);
  font-size: 16px;
  line-height: 1.55;
  color: var(--text);
  background: var(--bg);
}

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

/* Header / nav */
header {
  border-bottom: 1px solid var(--rule);
}
.header-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 1.1rem 1.25rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 0.5rem 1.5rem;
}
.site-title {
  font-size: 1.5rem;
  letter-spacing: 0.02em;
  color: var(--text);
  font-weight: 600;
}
.site-title:hover { text-decoration: none; }
nav { font-family: var(--sans); font-size: 0.95rem; }
nav a {
  color: var(--muted);
  margin-left: 1.4rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  font-size: 0.82rem;
}
nav a:first-child { margin-left: 0; }
nav a:hover { color: var(--text); text-decoration: none; }
nav a.active { color: var(--accent); font-weight: 600; }

/* Social icons in nav */
nav { display: flex; align-items: center; }
.nav-social {
  display: inline-flex;
  align-items: center;
  margin-left: 1.4rem;
  padding-left: 1.2rem;
  border-left: 1px solid var(--rule);
}
.nav-social a {
  margin-left: 0.8rem;
  text-transform: none;
  letter-spacing: 0;
  display: inline-flex;
}
.nav-social a:first-child { margin-left: 0; }
.nav-social svg { width: 17px; height: 17px; display: block; }
.nav-social a:hover { color: var(--accent); }

/* Layout */
main {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 1.8rem 1.25rem 2.5rem;
}
h1 {
  font-size: 1.9rem;
  font-weight: 600;
  margin: 0 0 1.2rem;
  color: var(--heading);
}
h1::after {
  content: "";
  display: block;
  width: 3.2rem;
  height: 3px;
  background: var(--accent);
  border-radius: 2px;
  margin-top: 0.5rem;
}
h2 {
  font-size: 1.3rem;
  font-weight: 600;
  margin: 2.2rem 0 0.8rem;
  color: var(--heading);
  border-bottom: 2px solid var(--accent);
  padding-bottom: 0.35rem;
}
.muted { color: var(--muted); }

/* Intro lede under the page title */
.lede {
  font-size: 0.9rem;
  line-height: 1.6;
  color: var(--muted);
}
.lede + .lede { margin-top: 0.4rem; }
.lede-rule {
  border: none;
  border-top: 1px solid var(--rule);
  margin: 1.8rem 0 0;
}

/* Home */
.home-grid {
  display: grid;
  grid-template-columns: 240px 1fr;
  gap: 2rem;
  align-items: start;
}
.home-grid img {
  width: 100%;
  border-radius: 4px;
}
.home-name h1 { margin-bottom: 0.2rem; }
.affiliation {
  font-family: var(--sans);
  color: var(--muted);
  font-size: 0.95rem;
  margin: 0 0 1.5rem;
}
@media (max-width: 700px) {
  .home-grid { grid-template-columns: 1fr; }
  .home-grid img { max-width: 320px; }
}

/* Research entries */
.paper { margin-bottom: 1.8rem; }
.paper-title { font-weight: 600; color: var(--heading); }
.paper-note {
  font-family: var(--sans);
  font-size: 0.85rem;
  color: var(--muted);
}
/* Abstract / PDF chips */
.paper-actions {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.6rem;
  margin-top: 0.5rem;
  font-family: var(--sans);
}
.chip,
.paper-actions summary {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  border: 1px solid var(--accent);
  color: var(--accent);
  font-size: 0.78rem;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  padding: 0.28rem 0.75rem;
  border-radius: 3px;
  cursor: pointer;
  user-select: none;
  list-style: none;
}
.paper-actions summary::-webkit-details-marker { display: none; }
.chip:hover,
.paper-actions summary:hover {
  background: var(--accent);
  color: #fff;
  text-decoration: none;
}
.paper-actions details[open] summary {
  background: var(--accent);
  color: #fff;
}
.chip svg { width: 13px; height: 13px; }
.abstract {
  display: none;
  margin: 0.7rem 0 0;
  font-size: 0.95rem;
  color: var(--muted);
}
.paper:has(details[open]) .abstract { display: block; }

/* Buttons */
.btn {
  display: inline-block;
  font-family: var(--sans);
  font-size: 0.85rem;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  border: 1px solid var(--accent);
  padding: 0.55rem 1.1rem;
  border-radius: 3px;
  margin: 0.3rem 0.6rem 0.3rem 0;
}
.btn:hover { background: var(--accent); color: #fff; text-decoration: none; }

/* Teaching */
.course { margin-bottom: 1.6rem; }
.course strong { color: var(--heading); }
ul.ta-list { padding-left: 1.2rem; }
ul.ta-list li { margin-bottom: 0.35rem; }

/* CV embed */
.cv-frame {
  width: 100%;
  height: 85vh;
  border: 1px solid var(--rule);
  border-radius: 4px;
  margin-top: 1rem;
}

/* Footer */
footer {
  border-top: 1px solid var(--rule);
  margin-top: 2rem;
}
.footer-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 1.5rem 1.25rem;
  font-family: var(--sans);
  font-size: 0.85rem;
  color: var(--muted);
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 0.5rem 1.5rem;
}
.footer-inner a { color: var(--muted); margin-right: 1.2rem; }
.footer-inner a:hover { color: var(--text); }