/* =========================================================
   Changyoon Lee — personal site
   Theme: conversational / dialogue. Clean, professional, readable.
   ========================================================= */

:root {
  /* Palette */
  --bg:            #f7f6f3;   /* warm paper */
  --bg-soft:       #efede7;
  --surface:       #ffffff;
  --ink:           #1c1b22;   /* near-black text */
  --ink-soft:      #55535f;
  --ink-faint:     #86838f;
  --line:          #e4e1da;

  --accent:        #5b57d6;   /* indigo — "assistant" */
  --accent-soft:   #ecebfb;
  --accent-ink:    #3b37a8;
  --user:          #128a6f;   /* teal — "learner/user" */
  --user-soft:     #e2f2ee;

  /* Type */
  --serif: "Newsreader", "Iowan Old Style", Georgia, "Times New Roman", serif;
  --sans:  "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  --mono:  "JetBrains Mono", ui-monospace, "SF Mono", Menlo, Consolas, monospace;

  --radius:   16px;
  --radius-sm:10px;
  --shadow:   0 1px 2px rgba(28,27,34,.04), 0 8px 24px rgba(28,27,34,.06);
  --maxw:     1160px;   /* whole page: ~820px content column + sidebar beside it */
  --contentw: 820px;    /* reading width for single-column pages */
}

/* ---------- Reset ---------- */
*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  font-family: var(--sans);
  font-size: 17px;
  line-height: 1.65;
  color: var(--ink);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
}
img { max-width: 100%; display: block; }
a { color: var(--accent-ink); text-decoration: none; }
a:hover { text-decoration: underline; }

/* ---------- Layout ---------- */
.wrap { max-width: var(--maxw); margin: 0 auto; padding: 0 24px; }

/* ---------- Top nav ---------- */
.nav {
  position: sticky; top: 0; z-index: 50;
  backdrop-filter: saturate(1.2) blur(10px);
  background: rgba(247,246,243,.82);
  border-bottom: 1px solid var(--line);
}
.nav__inner {
  max-width: var(--maxw); margin: 0 auto; padding: 12px 24px;
  display: flex; align-items: center; gap: 20px;
}
.nav__brand {
  font-family: var(--serif); font-weight: 600; font-size: 1.05rem;
  color: var(--ink); letter-spacing: .2px; margin-right: auto;
  display: inline-flex; align-items: center; gap: 9px;
}
.nav__brand:hover { text-decoration: none; }
.nav__dot {
  width: 10px; height: 10px; border-radius: 50%;
  background: var(--accent); box-shadow: 0 0 0 4px var(--accent-soft);
  flex: none;
}
.nav__links { display: flex; align-items: center; gap: 4px; flex-wrap: wrap; }
.nav__links a {
  color: var(--ink-soft); font-size: .95rem; font-weight: 500;
  padding: 6px 12px; border-radius: 999px; transition: all .15s ease;
}
.nav__links a:hover { background: var(--bg-soft); color: var(--ink); text-decoration: none; }
.nav__links a.is-active { background: var(--accent-soft); color: var(--accent-ink); }
.nav__cv {
  border: 1px solid var(--accent); color: var(--accent-ink) !important;
  background: var(--surface);
}
.nav__cv:hover { background: var(--accent) !important; color: #fff !important; }

/* ---------- Two-column layout (sidebar + content) ---------- */
.layout {
  display: grid;
  grid-template-columns: 250px minmax(0, 1fr);
  gap: 44px;
  align-items: start;
  padding: 40px 0 8px;
}
.content { min-width: 0; }

.sidebar { position: sticky; top: 80px; }
.card {
  background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius);
  box-shadow: var(--shadow); padding: 22px 20px; text-align: center;
}
.card__photo {
  width: 128px; height: 128px; border-radius: 22px; object-fit: cover; margin: 0 auto 14px;
  border: 1px solid var(--line); background: var(--bg-soft);
}
.card__name { font-family: var(--serif); font-size: 1.35rem; font-weight: 600; margin: 0 0 4px; line-height: 1.15; }
.card__role { color: var(--ink-soft); font-size: .92rem; margin: 0 0 4px; }
.card__role strong { color: var(--accent-ink); font-weight: 600; }
.card__affil { color: var(--ink-faint); font-size: .85rem; margin: 0 0 16px; }

/* sidebar links */
.side-links { display: flex; flex-direction: column; gap: 8px; text-align: left; }
.side-links a {
  display: inline-flex; align-items: center; gap: 10px;
  padding: 8px 12px; border-radius: 10px;
  border: 1px solid var(--line); background: var(--bg);
  color: var(--ink-soft); font-size: .9rem; font-weight: 500;
  transition: all .15s ease;
}
.side-links a:hover { text-decoration: none; border-color: var(--accent); color: var(--accent-ink); background: var(--accent-soft); transform: translateX(2px); }
.side-links svg { width: 17px; height: 17px; flex: none; }
.side-links .side__cv {
  justify-content: center; border-color: var(--accent); color: var(--accent-ink);
  background: var(--accent-soft); font-weight: 600; margin-top: 4px;
}
.side-links .side__cv:hover { background: var(--accent); color: #fff; }

@media (max-width: 820px) {
  .layout { grid-template-columns: 1fr; gap: 24px; padding-top: 26px; }
  .sidebar { position: static; }
  .card { display: grid; grid-template-columns: 96px 1fr; gap: 6px 18px; text-align: left; align-items: center; padding: 18px; }
  .card__photo { width: 96px; height: 96px; margin: 0; grid-row: 1 / span 3; }
  .card__name, .card__role, .card__affil { margin: 0; }
  .side-links { grid-column: 1 / -1; flex-direction: row; flex-wrap: wrap; margin-top: 12px; }
  .side-links a { padding: 7px 11px; }
  .side-links .side__cv { flex-basis: 100%; }
}

/* ---------- Chat bubbles ---------- */
.chat { display: flex; flex-direction: column; gap: 14px; }
.msg { display: flex; gap: 12px; align-items: flex-end; max-width: 100%; }
.msg__avatar {
  flex: none; width: 34px; height: 34px; border-radius: 50%;
  display: grid; place-items: center; font-size: .78rem; font-weight: 700;
  font-family: var(--sans); color: #fff; margin-bottom: 2px;
}
.msg--bot .msg__avatar { background: var(--accent); }
.msg--user { flex-direction: row-reverse; }
.msg--user .msg__avatar { background: var(--user); }

.bubble {
  position: relative;
  padding: 13px 17px;
  border-radius: 18px;
  box-shadow: var(--shadow);
  font-size: 1.02rem;
}
.msg--bot .bubble {
  background: var(--surface); border: 1px solid var(--line);
  border-bottom-left-radius: 5px;
}
.msg--user .bubble {
  background: var(--user-soft); border: 1px solid #cfe8e0;
  border-bottom-right-radius: 5px; color: #0d4c3e;
}
.bubble p { margin: 0 0 .5em; }
.bubble p:last-child { margin-bottom: 0; }

/* typing dots — hidden unless JS turns them on during streaming */
.typing { display: none; gap: 5px; padding: 4px 2px; }
.js .typing.is-on { display: inline-flex; }
.typing span {
  width: 7px; height: 7px; border-radius: 50%; background: var(--ink-faint);
  animation: blink 1.2s infinite ease-in-out;
}
.typing span:nth-child(2){ animation-delay: .2s; }
.typing span:nth-child(3){ animation-delay: .4s; }
@keyframes blink { 0%,60%,100%{opacity:.25; transform:translateY(0)} 30%{opacity:1; transform:translateY(-2px)} }

/* caret for streaming text */
.caret::after {
  content: "▋"; margin-left: 1px; color: var(--accent);
  animation: caret 1s steps(1) infinite;
}
@keyframes caret { 50% { opacity: 0; } }

/* reveal animation — only hide when JS is available to reveal it */
.js .reveal { opacity: 0; transform: translateY(10px); }
.js .reveal.in { opacity: 1; transform: none; transition: opacity .5s ease, transform .5s ease; }

/* ---------- Hero ---------- */
.hero { padding: 56px 0 12px; }
.hero__grid {
  display: grid; grid-template-columns: 132px 1fr; gap: 28px; align-items: center;
  margin-bottom: 30px;
}
.hero__photo {
  width: 132px; height: 132px; border-radius: 24px; object-fit: cover;
  border: 1px solid var(--line); box-shadow: var(--shadow); background: var(--bg-soft);
}
.hero__name { font-family: var(--serif); font-size: 2.1rem; line-height: 1.1; margin: 0 0 6px; font-weight: 600; }
.hero__role { color: var(--ink-soft); font-size: 1.05rem; margin: 0 0 14px; }
.hero__role strong { color: var(--accent-ink); font-weight: 600; }

/* ---------- Social row ---------- */
.social { display: flex; flex-wrap: wrap; gap: 10px; margin-top: 4px; }
.social a {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 8px 14px; border-radius: 999px;
  border: 1px solid var(--line); background: var(--surface);
  color: var(--ink-soft); font-size: .9rem; font-weight: 500;
  transition: all .15s ease;
}
.social a:hover { text-decoration: none; border-color: var(--accent); color: var(--accent-ink); transform: translateY(-1px); }
.social svg { width: 17px; height: 17px; flex: none; }
.social .social__cv { border-color: var(--accent); color: var(--accent-ink); background: var(--accent-soft); }
.social .social__cv:hover { background: var(--accent); color: #fff; }

/* ---------- Sections ---------- */
section { padding: 40px 0; }
.section-label {
  display: inline-flex; align-items: center; gap: 8px;
  font-family: var(--mono); font-size: .72rem; letter-spacing: .12em;
  text-transform: uppercase; color: var(--accent-ink);
  background: var(--accent-soft); padding: 5px 11px; border-radius: 999px;
  margin-bottom: 18px;
}
.section-head { display: flex; align-items: baseline; justify-content: space-between; gap: 12px; flex-wrap: wrap; }
.link-more { font-size: .9rem; font-weight: 500; white-space: nowrap; }
.link-more::after { content: " →"; }
h2.section-title { font-family: var(--serif); font-size: 1.55rem; font-weight: 600; margin: 0 0 6px; }
.section-sub { color: var(--ink-soft); margin: 0 0 22px; }

.prose { font-size: 1.05rem; }
.prose p { margin: 0 0 1.05em; }

/* research chips */
.chips { display: flex; flex-wrap: wrap; gap: 8px; margin: 8px 0 4px; }
.chip {
  font-size: .85rem; padding: 5px 12px; border-radius: 999px;
  background: var(--surface); border: 1px solid var(--line); color: var(--ink-soft);
}
.chip strong { color: var(--accent-ink); font-weight: 600; }

/* ---------- Publications ---------- */
.pub {
  background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 20px 22px; margin-bottom: 16px; box-shadow: var(--shadow);
  transition: border-color .15s ease, transform .15s ease;
}
.pub:hover { border-color: var(--accent); transform: translateY(-2px); }
.pub__top { display: flex; align-items: baseline; gap: 12px; flex-wrap: wrap; }
.pub__venue {
  font-family: var(--mono); font-size: .72rem; letter-spacing: .05em; text-transform: uppercase;
  color: var(--accent-ink); background: var(--accent-soft); padding: 4px 9px; border-radius: 6px; flex: none;
}
.pub__year { color: var(--ink-faint); font-size: .85rem; margin-left: auto; font-family: var(--mono); }
.pub__title { font-family: var(--serif); font-size: 1.18rem; font-weight: 600; margin: 10px 0 6px; line-height: 1.3; }
.pub__authors { color: var(--ink-soft); font-size: .95rem; margin: 0 0 4px; }
.pub__authors .me { color: var(--ink); font-weight: 600; text-decoration: underline; text-decoration-color: var(--accent); text-underline-offset: 3px; }
.pub__note { color: var(--ink-faint); font-size: .82rem; font-style: italic; margin: 2px 0 0; }
.pub__desc { color: var(--ink-soft); font-size: .96rem; margin: 8px 0 12px; }
.pub__award {
  display: inline-flex; align-items: center; gap: 6px;
  font-size: .85rem; font-weight: 600; color: #9a6a00;
  background: #fdf2d6; border: 1px solid #f4e0a8; padding: 4px 10px; border-radius: 999px;
}
.pub__award svg { width: 14px; height: 14px; flex: none; }
.pub__links { display: flex; flex-wrap: wrap; gap: 8px; }
.pub__links a {
  font-size: .82rem; font-weight: 500; padding: 5px 12px; border-radius: 999px;
  border: 1px solid var(--line); color: var(--ink-soft); background: var(--bg);
  transition: all .15s ease;
}
.pub__links a:hover { text-decoration: none; border-color: var(--accent); color: var(--accent-ink); background: var(--accent-soft); }

/* filter tabs */
.filters { display: flex; flex-wrap: wrap; gap: 8px; margin-bottom: 24px; }
.filters button {
  font-family: var(--sans); font-size: .88rem; font-weight: 500; cursor: pointer;
  padding: 7px 15px; border-radius: 999px; border: 1px solid var(--line);
  background: var(--surface); color: var(--ink-soft); transition: all .15s ease;
}
.filters button:hover { border-color: var(--accent); color: var(--accent-ink); }
.filters button.is-active { background: var(--accent); color: #fff; border-color: var(--accent); }

/* ---------- News timeline ---------- */
.timeline { position: relative; padding-left: 26px; }
.timeline::before {
  content: ""; position: absolute; left: 6px; top: 6px; bottom: 6px;
  width: 2px; background: linear-gradient(var(--accent), var(--line));
}
.news-item { position: relative; margin-bottom: 26px; }
.news-item::before {
  content: ""; position: absolute; left: -26px; top: 6px;
  width: 12px; height: 12px; border-radius: 50%;
  background: var(--surface); border: 2px solid var(--accent);
}
.news-item.is-fresh::before { background: var(--accent); box-shadow: 0 0 0 5px var(--accent-soft); }
.news-item__date {
  font-family: var(--mono); font-size: .78rem; color: var(--ink-faint);
  letter-spacing: .04em; margin-bottom: 4px;
}
.news-item__body {
  background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius-sm);
  padding: 14px 18px; box-shadow: var(--shadow);
}
.news-item__body p { margin: 0; }
.tag {
  display: inline-block; font-family: var(--mono); font-size: .68rem; text-transform: uppercase;
  letter-spacing: .06em; color: var(--user); background: var(--user-soft);
  padding: 2px 8px; border-radius: 5px; margin-bottom: 6px;
}

/* ---------- CV page ---------- */
.cv-download {
  display: inline-flex; align-items: center; gap: 9px; margin-top: 6px;
  padding: 9px 16px; border-radius: 999px; font-size: .92rem; font-weight: 600;
  border: 1px solid var(--accent); color: #fff; background: var(--accent);
  transition: all .15s ease;
}
.cv-download:hover { text-decoration: none; background: var(--accent-ink); border-color: var(--accent-ink); transform: translateY(-1px); }
.cv-download svg { width: 17px; height: 17px; flex: none; }
.cv-updated { color: var(--ink-faint); font-size: .85rem; font-family: var(--mono); margin-left: 12px; }

.cv-section { padding: 26px 0 6px; }
.cv-section + .cv-section { border-top: 1px solid var(--line); }
.cv-section__title {
  font-family: var(--serif); font-size: 1.3rem; font-weight: 600; color: var(--accent-ink);
  margin: 0 0 14px;
}
.cv-lead { font-size: 1.03rem; color: var(--ink-soft); margin: 0; max-width: 68ch; }

.cv-entry { margin-bottom: 15px; }
.cv-entry__row { display: flex; justify-content: space-between; align-items: baseline; gap: 14px; flex-wrap: wrap; }
.cv-entry__title { font-weight: 600; font-size: 1.02rem; }
.cv-entry__date { color: var(--ink-faint); font-family: var(--mono); font-size: .82rem; white-space: nowrap; }
.cv-entry__org { color: var(--ink-soft); font-size: .95rem; margin-top: 1px; }
.cv-items { margin: 6px 0 0; padding-left: 18px; color: var(--ink-soft); font-size: .93rem; }
.cv-items li { margin-bottom: 3px; }
.cv-year { color: var(--ink-faint); font-family: var(--mono); font-size: .8rem; }

.cv-pub { margin-bottom: 16px; padding-bottom: 15px; border-bottom: 1px dashed var(--line); }
.cv-pub:last-child { border-bottom: none; }
.cv-pub__title { font-family: var(--serif); font-weight: 600; font-size: 1.05rem; line-height: 1.3; }
.cv-pub__authors { color: var(--ink-soft); font-size: .92rem; margin: 4px 0 2px; }
.cv-pub__venue { color: var(--accent-ink); font-size: .85rem; font-style: italic; margin-bottom: 8px; }

/* ---------- Callout / edit hint ---------- */
.hint {
  font-size: .85rem; color: var(--ink-faint); border: 1px dashed var(--line);
  border-radius: var(--radius-sm); padding: 10px 14px; margin: 20px 0;
  background: var(--bg-soft); font-family: var(--mono);
}

/* ---------- Footer ---------- */
.footer {
  border-top: 1px solid var(--line); margin-top: 40px; padding: 28px 0 48px;
  color: var(--ink-faint); font-size: .86rem;
}
.footer .wrap { display: flex; justify-content: space-between; gap: 12px; flex-wrap: wrap; }
.footer a { color: var(--ink-soft); }

/* ---------- Page header (sub pages) ---------- */
.page-head { padding: 44px 0 6px; }
.page-head h1 { font-family: var(--serif); font-size: 2rem; font-weight: 600; margin: 12px 0 6px; }
.page-head p { color: var(--ink-soft); margin: 0; max-width: 60ch; }

/* ---------- Responsive ---------- */
@media (max-width: 620px) {
  body { font-size: 16px; }
  .hero__grid { grid-template-columns: 1fr; text-align: left; gap: 18px; justify-items: start; }
  .hero__photo { width: 104px; height: 104px; }
  .hero__name { font-size: 1.7rem; }
  .nav__brand { font-size: .98rem; }
  .nav__links a { padding: 6px 9px; }
  .pub__year { margin-left: 0; }
}

/* ---------- Reduced motion ---------- */
@media (prefers-reduced-motion: reduce) {
  * { animation: none !important; transition: none !important; }
  .js .reveal { opacity: 1; transform: none; }
  html { scroll-behavior: auto; }
}