/* =========================================================
   Dayoung Jeong — Academic personal website
   Minimal academic style, no frameworks, no external assets
   ========================================================= */

/* Self-hosted (not CDN-linked) — same font used in the index.html splash */
@font-face {
  font-family: 'Pinyon Script';
  src: url('assets/fonts/PinyonScript.ttf') format('truetype');
  font-display: swap;
}

:root {
  --color-bg: #ffffff;
  --color-text: #222222;
  --color-muted: #5a5a5a;
  --color-accent: #1a3a5c;
  --color-border: #e2e2e2;
  --font-serif: Georgia, 'Times New Roman', Times, serif;
  --font-sans: -apple-system, BlinkMacSystemFont, 'Segoe UI', Helvetica, Arial, sans-serif;
  --max-width: 860px;
}

* {
  box-sizing: border-box;
}

/* Keeps an element in the accessibility tree / DOM (screen readers, SEO)
   without showing it visually — used for a page's h1 when the visible
   heading role is already served by other on-screen text. */
.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

html {
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  background: var(--color-bg);
  color: var(--color-text);
  font-family: var(--font-serif);
  font-size: 17px;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

a {
  color: var(--color-accent);
  text-decoration: none;
  border-bottom: 1px solid transparent;
}

a:hover,
a:focus {
  border-bottom-color: var(--color-accent);
}

h1, h2, h3 {
  font-family: var(--font-serif);
  font-weight: normal;
  color: var(--color-text);
  line-height: 1.3;
}

h1 {
  font-size: 2rem;
  margin: 0 0 1.2rem;
}

h2 {
  font-size: 1.3rem;
  margin: 2.5rem 0 1rem;
  padding-bottom: 0.4rem;
  border-bottom: 1px solid var(--color-border);
}

p {
  margin: 0 0 1.2rem;
}

/* ---------- Layout shell ---------- */

.site-wrap {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 1.5rem;
}

/* ---------- Top navigation ---------- */

.site-header {
  border-bottom: 1px solid var(--color-border);
}

.nav-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 1.25rem 1.5rem;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
}

.site-name {
  font-family: 'Pinyon Script', var(--font-serif);
  font-size: 2rem;
  color: var(--color-text);
  border-bottom: none;
  letter-spacing: 0.01em;
}

.site-name:hover {
  color: var(--color-accent);
}

.site-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 1.5rem;
}

.site-nav a {
  font-family: var(--font-sans);
  color: var(--color-muted);
  font-size: 0.95rem;
  letter-spacing: 0.02em;
  border-bottom: 1px solid transparent;
  padding-bottom: 2px;
}

.site-nav a:hover {
  color: var(--color-accent);
}

.site-nav a[aria-current="page"] {
  color: var(--color-accent);
  border-bottom-color: var(--color-accent);
}

/* ---------- Main content ---------- */

.site-main {
  padding: 3rem 0 4rem;
}

/* ---------- Home page two-column layout ---------- */

.home-layout {
  display: flex;
  gap: 3rem;
  align-items: flex-start;
}

.home-sidebar {
  flex: 0 0 260px;
  width: 260px;
}

.home-photo {
  width: 100%;
  height: auto;
  display: block;
  border: 1px solid var(--color-border);
  margin-bottom: 1.5rem;
  background: #f4f4f4;
}

.home-sidebar h2.name {
  font-size: 1.3rem;
  margin: 0 0 0.3rem;
  border-bottom: none;
  padding-bottom: 0;
}

.home-title {
  color: var(--color-muted);
  font-size: 0.95rem;
  margin: 0 0 1.3rem;
  line-height: 1.5;
}

.contact-block {
  font-family: var(--font-sans);
  /* Small enough that "Chungnam National University Law School" fits on
     one line within the 260px sidebar, rather than wrapping mid-phrase. */
  font-size: 0.84rem;
  color: var(--color-muted);
  line-height: 1.6;
}

.contact-block dt {
  font-weight: bold;
  color: var(--color-text);
  margin-top: 0.9rem;
}

.contact-block dt:first-child {
  margin-top: 0;
}

.contact-block dd {
  margin: 0.15rem 0 0;
}

.home-content {
  flex: 1 1 auto;
  min-width: 0;
}

.research-interests {
  color: var(--color-muted);
}

/* ---------- Publication lists ---------- */

.pub-list {
  list-style: none;
  margin: 0 0 1rem;
  padding: 0;
  counter-reset: pub-counter;
}

.pub-list li {
  counter-increment: pub-counter;
  position: relative;
  margin: 0 0 1.1rem;
  padding-left: 2.6rem;
  line-height: 1.6;
}

.pub-list li::before {
  content: counter(pub-counter) ".";
  position: absolute;
  left: 0;
  top: 0;
  width: 2rem;
  text-align: right;
  color: var(--color-muted);
  font-variant-numeric: tabular-nums;
}

.pub-list.plain {
  list-style: disc;
  padding-left: 1.4rem;
}

.pub-list.plain li {
  padding-left: 0;
  position: static;
}

.pub-list.plain li::before {
  content: none;
}

.award {
  color: var(--color-accent);
  font-size: 0.88em;
}

/* Expandable English abstract per publication */

.abstract {
  margin-top: 0.35rem;
}

.abstract summary {
  display: inline-block;
  cursor: pointer;
  font-family: var(--font-sans);
  font-size: 0.78rem;
  letter-spacing: 0.04em;
  color: var(--color-accent);
  border: 1px solid var(--color-border);
  border-radius: 3px;
  padding: 0.05rem 0.55rem;
  user-select: none;
}

.abstract summary:hover {
  border-color: var(--color-accent);
}

.abstract[open] summary {
  background: var(--color-accent);
  color: #ffffff;
  border-color: var(--color-accent);
}

.abstract p {
  font-size: 0.92rem;
  color: var(--color-muted);
  line-height: 1.65;
  margin: 0.6rem 0 0.4rem;
  padding: 0.8rem 1rem;
  background: #f7f8fa;
  border-left: 2px solid var(--color-accent);
}

/* ---------- Simple lists (talks, funding, courses) ---------- */

.simple-list {
  margin: 0 0 1rem;
  padding-left: 1.4rem;
}

.simple-list li {
  margin: 0 0 0.9rem;
  line-height: 1.6;
}

.course-group {
  margin: 0 0 1.5rem;
}

.course-group h3 {
  font-family: var(--font-serif);
  font-size: 1.05rem;
  font-weight: normal;
  font-style: italic;
  color: var(--color-accent);
  margin: 0 0 0.4rem;
}

.course-group p {
  color: var(--color-text);
  margin: 0;
  line-height: 1.8;
}

.intro-text {
  font-family: var(--font-serif);
  font-size: 1.05rem;
  color: var(--color-muted);
  max-width: 70ch;
}

.interests-list {
  list-style: none;
  margin: 0 0 1.2rem;
  padding: 0;
  color: var(--color-muted);
}

.interests-list li {
  margin: 0 0 0.35rem;
  padding-left: 1.1rem;
  position: relative;
}

.interests-list li::before {
  content: "·";
  position: absolute;
  left: 0;
  color: var(--color-accent);
  font-weight: bold;
}

/* ---------- Footer ---------- */

.site-footer {
  font-family: var(--font-sans);
  border-top: 1px solid var(--color-border);
  padding: 1.5rem 0 2.5rem;
  color: var(--color-muted);
  font-size: 0.85rem;
}

.site-footer .site-wrap {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 0.4rem;
}

/* ---------- Back-to-top button ---------- */

.back-to-top {
  position: fixed;
  right: 1.5rem;
  bottom: 1.5rem;
  z-index: 20;
  width: 2.6rem;
  height: 2.6rem;
  display: flex;
  align-items: center;
  justify-content: center;
  border: 1px solid var(--color-border);
  border-radius: 50%;
  background: var(--color-bg);
  color: var(--color-accent);
  box-shadow: 0 1px 4px rgba(0, 0, 0, 0.12);
  opacity: 0;
  pointer-events: none;
  transform: translateY(8px);
  transition: opacity 0.2s ease, transform 0.2s ease;
}

.back-to-top.is-visible {
  opacity: 1;
  pointer-events: auto;
  transform: translateY(0);
}

.back-to-top:hover,
.back-to-top:focus {
  border-color: var(--color-accent);
}

.back-to-top svg {
  width: 1.1rem;
  height: 1.1rem;
}

/* ---------- Responsive ---------- */

@media (max-width: 600px) {
  body {
    font-size: 16px;
  }

  /* Keep the logo + nav visible while scrolling long pages (Research in
     particular runs to many screens of publications) — desktop is left
     alone since its shorter scroll doesn't need this. */
  .site-header {
    position: sticky;
    top: 0;
    z-index: 10;
    background: var(--color-bg);
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.06);
  }

  .nav-inner {
    padding: 1.1rem 1.25rem;
  }

  .site-nav {
    gap: 0.4rem 1rem;
    row-gap: 0.5rem;
  }

  /* Larger touch targets on mobile (min ~44px tap height per Apple/Google guidance) */
  .site-nav a {
    padding: 0.5rem 0.1rem;
  }

  .home-layout {
    flex-direction: column;
    align-items: center;
    gap: 2rem;
  }

  .home-sidebar {
    flex: 1 1 auto;
    width: 100%;
    max-width: 320px;
  }

  /* Keep "Chungnam National University Law School" on one line at
     mobile widths rather than wrapping mid-word. */
  .contact-block dd {
    font-size: 0.78rem;
  }

  h1 {
    font-size: 1.6rem;
  }

  h2 {
    font-size: 1.15rem;
  }

  /* Larger tap target for abstract toggle buttons */
  .abstract summary {
    padding: 0.35rem 0.7rem;
    font-size: 0.82rem;
  }

  .pub-list li {
    padding-left: 2.1rem;
  }

  .pub-list li::before {
    width: 1.6rem;
  }
}