/* ============================================================
   Ye Joon Lee — personal website
   ============================================================ */

:root {
  --bg: #ffffff;
  --bg-elev: #ffffff;
  --bg-muted: #f6f6f3;
  --fg: #15141a;
  --fg-soft: #2e2c34;
  --fg-muted: #5e5d63;
  --fg-faint: #8e8d92;
  --author-self: #7d7c82;  /* coauthor gray, a touch darker — own-name byline */
  --rule: #e9e9e3;
  --rule-strong: #d3d3cc;

  --accent: #4E2A84;       /* Northwestern purple */
  --accent-soft: #6b4aa3;
  --accent-ink: #3a1f63;
  --accent-tint: #efe8f5;

  --cv-heading: #4f7c8d;   /* steel-teal — matches CV section headings */

  --font-display: "EB Garamond", Georgia, serif;
  --font-body: "Source Serif 4", "Source Serif Pro", Georgia, "Times New Roman", serif;
  --font-sans: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  --font-mono: "JetBrains Mono", ui-monospace, Menlo, monospace;

  --wide: 1100px;
  --mid: 880px;
  --narrow: 680px;
  --gutter: clamp(20px, 5vw, 56px);

  --t-fast: 120ms;
  --t-med: 220ms;
}

[data-theme="dark"] {
  --bg: #232328;
  --bg-elev: #2c2c33;
  --bg-muted: #2a2a30;
  --fg: #edece6;
  --fg-soft: #cfcec9;
  --fg-muted: #989899;
  --fg-faint: #76767a;
  --author-self: #7e7e82;  /* coauthor gray, a touch brighter — own-name byline */
  --rule: #3a3a40;
  --rule-strong: #4a4a52;

  --accent: #b29ae0;
  --accent-soft: #c4abe9;
  --accent-ink: #d3bff0;
  --accent-tint: #352a48;

  --cv-heading: #7aaec0;   /* steel-teal, lightened for dark bg */
}

html { color-scheme: light; }
html[data-theme="dark"] { color-scheme: dark; }

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--fg);
  font-family: var(--font-body);
  font-size: 19px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}
@media (min-width: 720px) { body { font-size: 20px; } }
@media (min-width: 1000px) { body { font-size: 21px; } }

p { margin: 0 0 1em; text-wrap: pretty; }
a { color: var(--accent); text-decoration: none; }
a:hover { color: var(--accent-ink); text-decoration: underline; text-underline-offset: 3px; }
a.plain { color: inherit; }
a.plain:hover { color: var(--accent); text-decoration: none; }

em, i { font-style: italic; }
strong { font-weight: 600; color: var(--fg); }
hr { border: 0; border-top: 1px solid var(--rule); margin: 2.5rem 0; }

h1, h2, h3, h4 {
  font-family: var(--font-display);
  font-weight: 600;
  line-height: 1.15;
  color: var(--fg);
  margin: 0 0 0.6em;
  letter-spacing: -0.01em;
}

.eyebrow {
  font-family: var(--font-sans);
  font-size: 12px;
  font-weight: 500;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--fg-muted);
  margin: 0 0 14px;
}

/* ------------------------------------------------------------ NAV */
.site-nav {
  position: sticky; top: 0; z-index: 20;
  background: var(--bg);
  border-bottom: 1px solid var(--rule);
  padding: 0 var(--gutter);
}
.site-nav .inner {
  max-width: var(--wide);
  margin: 0 auto;
  padding: 12px 0;
  display: flex; align-items: center; justify-content: space-between; gap: 1.5rem;
}
.site-nav .brand {
  font-family: var(--font-display);
  font-size: 25px;
  font-weight: 700;
  letter-spacing: -0.01em;
  color: var(--fg);
  display: inline-flex; align-items: center; gap: 14px;
}
.site-nav .brand:hover { color: var(--fg); }
.site-nav .theme-toggle {
  background: none;
  border: none;
  padding: 6px;
  margin-left: 4px;
  cursor: pointer;
  color: var(--fg-muted);
  display: inline-flex;
  align-items: center;
  border-radius: 4px;
  transition: color var(--t-fast);
}
.site-nav .theme-toggle:hover { color: var(--accent); }
.site-nav .theme-toggle svg { width: 18px; height: 18px; }
.site-nav .theme-toggle .icon-sun { display: none; }
.site-nav .theme-toggle .icon-moon { display: block; }
html[data-theme="dark"] .site-nav .theme-toggle .icon-sun { display: block; }
html[data-theme="dark"] .site-nav .theme-toggle .icon-moon { display: none; }
.site-nav .links {
  display: flex; gap: clamp(1.6rem, 4vw, 3rem); align-items: center;
}
.site-nav .links a {
  font-family: var(--font-sans);
  font-size: 15px;
  font-weight: 400;
  color: var(--fg-soft);
  padding: 2px 0;
  position: relative;
}
.site-nav .links a:hover { color: var(--accent); text-decoration: none; }
.site-nav .links a[aria-current="page"] {
  color: var(--fg);
  font-weight: 500;
}
.site-nav .links a[aria-current="page"]::after {
  content: "";
  position: absolute; left: 0; right: 0; bottom: -4px;
  height: 1.5px; background: var(--accent);
}
@media (max-width: 520px) {
  .site-nav .inner { padding: 14px 0; }
  .site-nav .brand { font-size: 19px; }
  .site-nav .links { gap: 14px; }
  .site-nav .links a { font-size: 14px; }
}
@media (max-width: 640px) {
  .hero-name { font-size: 43px; }
  .hero { padding: 32px 0 32px; gap: 24px; }
  .hero-portrait { order: -1; max-width: 240px; justify-self: center; }
}

/* ------------------------------------------------------------ LAYOUT */
main { padding: 0 var(--gutter); }
.container-wide   { max-width: var(--wide);   margin: 0 auto; }
.container-mid    { max-width: var(--mid);    margin: 0 auto; }
.container-narrow { max-width: var(--narrow); margin: 0 auto; }

.section { margin: 40px 0; }
@media (min-width: 720px) { .section { margin: 56px 0; } }

/* ------------------------------------------------------------ HERO */
.hero {
  padding: 60px 0 40px;
  display: grid;
  grid-template-columns: 1fr;
  gap: 40px;
  align-items: center;
  min-height: calc(100vh - 200px);
}
.hero-text { max-width: 720px; }
.hero-name {
  font-family: var(--font-display);
  font-size: 65px;
  font-weight: 700;
  line-height: 1.02;
  letter-spacing: -0.015em;
  color: var(--fg);
  margin: 0 0 18px;
}
.hero-name .ee-small {
  font-size: 0.82em;
  font-weight: 700;
  letter-spacing: -0.005em;
}
.hero-title {
  font-family: var(--font-sans);
  font-size: 18px;
  font-weight: 500;
  letter-spacing: 0.005em;
  color: var(--fg-muted);
  line-height: 1.6;
  margin: 0 0 28px;
}
.hero-title .inst-accent { color: var(--accent); font-weight: 600; }
.hero-bio {
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.6;
  color: var(--fg-soft);
  max-width: 80ch;
}

/* Portrait */
.hero-portrait {
  width: 100%;
  max-width: 360px;
  justify-self: start;
}
.hero-portrait .frame {
  aspect-ratio: 1/1;
  overflow: hidden;
  position: relative;
  border-radius: 12px;
}
.hero-portrait .frame img {
  width: 100%; height: 100%;
  object-fit: contain;
  display: block;
}

@media (min-width: 820px) {
  .hero {
    grid-template-columns: 1fr 360px;
    gap: 40px;
    padding: 60px 0 60px;
    min-height: calc(100vh - 120px);
  }
  .hero-portrait {
    width: 360px; max-width: 360px;
    justify-self: end;
    margin-top: 96px;
    margin-right: -20px;
  }
}

/* ------------------------------------------------------------ SOCIALS */
.socials {
  display: flex; gap: 18px; margin-top: 24px;
  font-family: var(--font-sans); font-size: 15px;
}
.socials a {
  color: var(--fg-muted);
  display: inline-flex; align-items: center; gap: 8px;
  padding: 4px 0;
  border-bottom: 1px solid transparent;
}
.socials a:hover { color: var(--accent); text-decoration: none; border-bottom-color: var(--accent); }
.socials svg { width: 18px; height: 18px; }

/* ------------------------------------------------------------ SECTION HEADERS */
.page-title {
  font-family: var(--font-display);
  font-size: clamp(41px, 5vw, 57px);
  font-weight: 600;
  letter-spacing: -0.015em;
  line-height: 1.1;
  color: var(--fg);
  margin: 0 0 18px;
}
.page-lead {
  font-family: var(--font-body);
  font-size: 20px;
  line-height: 1.55;
  color: var(--fg-soft);
  max-width: 100%;
  margin: 0;
}
.research-interests-label {
  font-family: var(--font-sans);
  font-size: 14px;
  font-weight: 600;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--accent);
  margin: 0 0 12px;
}
.research-interests {
  font-family: var(--font-body);
  font-size: 18px;
  color: var(--fg-soft);
  line-height: 1.6;
  margin: 0;
  max-width: 100%;
}
.section-head { margin-bottom: 16px; }
.section-head h2 {
  font-family: var(--font-sans);
  font-size: 17px;
  font-weight: 600;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--accent);
  margin: 0 0 20px;
}
.section-head p {
  font-family: var(--font-sans);
  color: var(--fg);
  max-width: 100%;
  margin: 0;
  font-size: 16px;
  line-height: 1.6;
}

/* ------------------------------------------------------------ NEWS LIST */
.news-list { list-style: none; padding: 0; margin: 0; }
.news-list li {
  display: grid;
  grid-template-columns: 1fr;
  gap: 4px 20px;
  padding: 18px 0;
  border-top: 1px solid var(--rule);
}
.news-list li:last-child { border-bottom: 1px solid var(--rule); }
.news-list .when {
  font-family: var(--font-sans);
  font-size: 13px; letter-spacing: 0.06em; text-transform: uppercase;
  color: var(--fg-muted);
}
.news-list .what {
  font-family: var(--font-body);
  font-size: 19px;
  color: var(--fg);
  line-height: 1.55;
}
@media (min-width: 640px) {
  .news-list li { grid-template-columns: 130px 1fr; gap: 20px; padding: 16px 0; align-items: baseline; }
  .news-list .when { padding-top: 3px; }
}

.section-head .research-line { margin: 0 0 0.45em; padding-left: 1.6em; }
/* empty line before the first stream and after the last */
.section-head p:not(.research-line) + .research-line { margin-top: 1em; }
.section-head .research-line:has(+ p:not(.research-line)) { margin-bottom: 1em; }

/* ------------------------------------------------------------ PAPERS */
.paper-group-heading {
  font-family: var(--font-sans);
  font-size: 17px;
  font-weight: 600;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--cv-heading);
  margin: 48px 0 14px;
}
.paper-group-heading:first-of-type { margin-top: 0; }
/* Box-free paper list with a thin left rule per entry. Status above the title:
   "R&R at <venue>", quiet; one notch-smaller, semibold title; First-Last names. */
.papers { list-style: none; padding: 0; margin: 0; }
.papers > li {
  padding: 11px 0;
  border-top: 1px solid var(--rule);
  display: flex;
  flex-direction: column;
  gap: 3px;
}
.papers > li:first-child { border-top: none; padding-top: 0; }
.papers > li:last-child { padding-bottom: 0; }
/* Whole status line italic, one size + one color. */
.p-status { font-family: var(--font-sans); font-size: 14.5px; font-style: italic; color: var(--fg-muted); margin: 0; }
.p-status .st,
.p-status .conj,
.p-status .vn { font-style: italic; font-weight: 400; color: inherit; }
.p-title {
  font-family: var(--font-sans);
  font-size: 16px;
  font-weight: 600;
  line-height: 1.3;
  color: var(--fg-soft);
  margin: 0;
}
.p-auth {
  font-family: var(--font-sans);
  font-size: 14px;
  color: var(--fg-soft);
  margin: 0;
  line-height: 1.5;
}
.p-auth .me { color: var(--fg); font-weight: 400; }
.eq-note { color: var(--accent); font-weight: 600; }
.eq-note-label {
  font-size: 12px;
  font-weight: 400;
  color: var(--fg-muted);
  font-style: italic;
  margin-left: 4px;
}
.p-note {
  font-family: var(--font-sans);
  font-size: 14px;
  font-style: italic;
  color: var(--fg-muted);
  margin: -1px 0 0;
  padding-left: 26px;
  line-height: 1.5;
}
.p-note::before { content: "– "; margin-left: -14px; font-style: normal; color: var(--fg-faint); }

/* ------------------------------------------------------------ CONTACT */
.contact-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 18px;
  font-family: var(--font-sans);
  font-size: 15px;
}
@media (min-width: 640px) {
  .contact-grid { grid-template-columns: auto 1fr; column-gap: 40px; row-gap: 12px; }
}
.contact-grid .key {
  font-weight: 500;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  font-size: 12px;
  color: var(--fg-muted);
  align-self: center;
}

/* Obfuscated email */
.obf-email {
  font-family: var(--font-mono);
  font-size: 0.95em;
  color: var(--fg);
  user-select: all;
}
.obf-email .obf-sep {
  color: var(--accent);
  font-weight: 500;
}

/* ------------------------------------------------------------ FOOTER */
.page-footer {
  border-top: 1px solid var(--rule);
  padding: 32px var(--gutter);
  margin-top: 80px;
  color: var(--fg-faint);
  font-family: var(--font-sans);
  font-size: 13px;
  letter-spacing: 0.04em;
  text-align: center;
}
.page-footer a { color: var(--fg-muted); }

/* ------------------------------------------------------------ PRINT */
@media print {
  .site-nav, .page-footer { display: none !important; }
  main { padding: 0; }
}