:root {
  --bg: #eeeeee;
  --sidebar-bg: #e4e5e7;
  --border: #d0d2d5;
  --text: #222831;
  --muted: #5b616a;
  --accent: #0092ca;
  --link: #0073a0;
  --sidebar-width: 260px;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans KR", sans-serif;
  font-size: 16px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

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

/* ---------- Sidebar ---------- */

/* Sidebar + content form one block, centered on wide screens. */
.page {
  display: flex;
  align-items: flex-start;
  max-width: calc(var(--sidebar-width) + 960px);
  margin: 0 auto;
}

.sidebar {
  position: sticky;
  top: 0;
  flex: none;
  width: var(--sidebar-width);
  height: 100vh;
  display: flex;
  flex-direction: column;
  padding: 2.5rem 1.5rem 1.5rem;
  background: var(--sidebar-bg);
  border-right: 1px solid var(--border);
  border-left: 1px solid var(--border);
  overflow-y: auto;
}

.profile { text-align: center; }

.avatar img {
  display: block;
  width: 128px;
  height: 128px;
  margin: 0 auto 1rem;
  border-radius: 50%;
  object-fit: cover;
  border: 3px solid #fff;
}

.name {
  display: block;
  color: var(--text);
  font-size: 1.3rem;
  font-weight: 700;
}
.name:hover { text-decoration: none; }

.bio {
  margin: .35rem 0 0;
  color: var(--muted);
  font-size: .85rem;
  line-height: 1.5;
}
.bio a { color: inherit; text-decoration: underline; text-decoration-color: var(--border); }
.bio a:hover { color: var(--text); }

.collapsible {
  display: flex;
  flex-direction: column;
  flex: 1;
}

.nav ul {
  list-style: none;
  margin: 2rem 0 0;
  padding: 0;
}

.nav a {
  display: block;
  padding: .45rem .8rem;
  border-radius: 6px;
  color: var(--muted);
  font-size: .8rem;
  font-weight: 600;
  letter-spacing: .06em;
  text-transform: uppercase;
}
.nav a:hover,
.nav a.active {
  background: rgba(0, 0, 0, .06);
  color: var(--text);
  text-decoration: none;
}
.nav a.active { box-shadow: inset 3px 0 0 var(--accent); }

/* Email / LinkedIn, right under the bio: a left-aligned list centered in the sidebar. */
.contact {
  display: inline-flex;
  flex-direction: column;
  align-items: flex-start;
  gap: .3rem;
  margin: .9rem 0 0;
  padding: 0;
  list-style: none;
  font-size: .8rem;
}
.contact a {
  display: inline-flex;
  align-items: center;
  gap: .45rem;
  color: var(--muted);
}
.contact a:hover { color: var(--accent); text-decoration: none; }
.contact svg { flex: none; width: 16px; height: 16px; }

/* Visually hidden but still focusable, so the mobile menu works from the keyboard. */
.nav-toggle {
  position: absolute;
  width: 1px;
  height: 1px;
  opacity: 0;
  pointer-events: none;
}
.nav-button { display: none; }

/* ---------- Content ---------- */

.content {
  display: flex;
  flex-direction: column;
  flex: 1;
  min-width: 0;
  min-height: 100vh;
  padding: 2.5rem 3rem 1.5rem;
}
.content article { flex: 1; }

.page-title {
  margin: 0 0 1.25rem;
  font-size: 1.6rem;
}

h2 {
  margin: 2.25rem 0 .9rem;
  padding-bottom: .3rem;
  border-bottom: 1px solid var(--border);
  font-size: 1.3rem;
  scroll-margin-top: 1.5rem;
}

article ul { padding-left: 1.3rem; }
article li { margin: .3rem 0; }
article li > ul { margin: .15rem 0; }
/* Publication entries: one item per paper, a bit of air between them. */
#publications + ul > li { margin-bottom: .9rem; }
#publications + ul p { margin: 0; }

sup { line-height: 0; }

footer {
  margin-top: 3rem;
  padding-top: 1rem;
  border-top: 1px solid var(--border);
  color: var(--muted);
  font-size: .85rem;
}

/* ---------- CV page ---------- */

.cv-actions { margin-bottom: 1rem; }

.btn {
  display: inline-block;
  padding: .4rem .9rem;
  border: 1px solid var(--link);
  border-radius: 6px;
  font-size: .9rem;
}
.btn:hover { background: var(--link); color: #fff; text-decoration: none; }

.cv-embed {
  display: block;
  width: 100%;
  height: calc(100vh - 12rem);
  min-height: 600px;
  border: 1px solid var(--border);
  border-radius: 6px;
  background: #fff;
}

/* ---------- Mobile: sidebar becomes a collapsible top bar ---------- */

@media (max-width: 768px) {
  .page { display: block; }

  .sidebar {
    position: static;
    width: auto;
    height: auto;
    padding: .9rem 1.1rem;
    border-right: 0;
    border-left: 0;
    border-bottom: 1px solid var(--border);
    overflow: visible;
  }

  .profile {
    display: flex;
    align-items: center;
    gap: .9rem;
    text-align: left;
  }
  .avatar img {
    width: 52px;
    height: 52px;
    margin: 0;
    border-width: 2px;
  }
  .name { font-size: 1.1rem; }
  .bio { margin-top: .1rem; font-size: .8rem; }

  .nav-button {
    display: flex;
    margin-left: auto;
    padding: .4rem;
    border-radius: 6px;
    color: var(--muted);
    cursor: pointer;
  }
  .nav-button svg { width: 24px; height: 24px; }
  .nav-toggle:focus-visible ~ .sidebar .nav-button { outline: 2px solid var(--accent); }

  .collapsible { display: none; }
  .nav-toggle:checked ~ .sidebar .collapsible { display: flex; }
  .nav-toggle:checked ~ .sidebar .nav-button { background: rgba(0, 0, 0, .06); }

  .nav ul { margin-top: .75rem; }
  .contact {
    display: flex;
    flex-direction: row;
    flex-wrap: wrap;
    gap: .2rem .9rem;
    margin-top: .3rem;
  }
  .desktop-only { display: none; }

  .content {
    min-height: 0;
    padding: 1.5rem 1.1rem 1.25rem;
  }

  .cv-embed { height: 75vh; min-height: 0; }
}