/* ============================================================
   Sohyun Kim — personal academic site
   Design system: "metadata rail"
   A mono gutter carries time (years) and status (In review /
   In prep.) beside every list on the site. Realized work sits on
   a solid rail; work in progress sits on a dashed one.

   Type: Archivo (headings, grotesque) over Source Serif 4 (body),
   with JetBrains Mono for the rail. Accent is a deep indigo; the
   variable --celadon names are kept so one edit recolors the site.
   ============================================================ */

:root {
  /* Palette — neutral paper, blue-black ink, deep indigo accent */
  --paper:        #FAFAF9;
  --paper-2:      #F0F0EC;
  --ink:          #14171D;
  --ink-2:        #4B515B;
  --ink-3:        #808791;
  --rule:         #DEDEDA;
  --rule-soft:    #EBEBE7;
  --celadon:      #2B4479;
  --celadon-2:    #8496BC;
  --celadon-wash: #ECEFF6;

  --display: "Archivo", "Helvetica Neue", Arial, sans-serif;
  --body:    "Source Serif 4", Georgia, "Times New Roman", serif;
  --mono:    "JetBrains Mono", ui-monospace, "SFMono-Regular", Menlo, monospace;

  --gutter: 76px;
  --gap:    28px;
  --maxw:   1040px;
}

*, *::before, *::after { box-sizing: border-box; }

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

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--body);
  font-size: 17.5px;
  line-height: 1.68;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { animation: none !important; transition: none !important; }
}

/* ---------- Layout primitives ---------- */

.wrap {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 0 28px;
}

.section { padding: 4.25rem 0; border-top: 1px solid var(--rule); }
.section[id] { scroll-margin-top: 100px; }
.section:first-of-type { border-top: 0; }

.eyebrow {
  font-family: var(--mono);
  font-size: 0.72rem;
  font-weight: 500;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--celadon);
  margin: 0 0 0.7rem;
}

h1, h2, h3, h4 {
  font-family: var(--display);
  font-weight: 600;
  color: var(--ink);
  letter-spacing: -0.018em;
  margin: 0;
}

h1 { font-weight: 700; font-stretch: 108%; }

h2 { font-size: 1.8rem; line-height: 1.22; font-stretch: 104%; margin-bottom: 1.6rem; }
h3 { font-size: 1.1rem; line-height: 1.32; letter-spacing: -0.01em; margin-bottom: 0.45rem; }
h4 { font-size: 1rem; font-weight: 600; margin-bottom: 0.4rem; }

p { margin: 0 0 1.05rem; }
p:last-child { margin-bottom: 0; }

.lede { font-size: 1.09rem; color: var(--ink-2); max-width: 66ch; }
.prose { max-width: 68ch; color: var(--ink-2); }
.prose strong { color: var(--ink); font-weight: 600; }

a { color: var(--celadon); text-decoration: none; }
a:hover { text-decoration: underline; text-underline-offset: 3px; }
a:focus-visible,
button:focus-visible {
  outline: 2px solid var(--celadon);
  outline-offset: 3px;
  border-radius: 2px;
}

em, i { font-style: italic; }

/* ---------- Header ---------- */

.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  background: rgba(250, 250, 249, 0.94);
  backdrop-filter: saturate(140%) blur(8px);
  border-bottom: 1px solid var(--rule);
}

.site-header .wrap {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1.5rem;
  min-height: 62px;
  flex-wrap: wrap;
}

.brand {
  font-family: var(--display);
  font-size: 0.98rem;
  font-weight: 700;
  color: var(--ink);
  letter-spacing: -0.005em;
}
.brand:hover { text-decoration: none; color: var(--celadon); }

.nav { display: flex; gap: 1.5rem; }

.nav a {
  font-family: var(--display);
  font-size: 0.86rem;
  letter-spacing: -0.004em;
  color: var(--ink-2);
  padding: 0.35rem 0;
  border-bottom: 1.5px solid transparent;
}
.nav a:hover { color: var(--ink); text-decoration: none; border-bottom-color: var(--celadon-2); }
.nav a[aria-current="page"] { color: var(--ink); border-bottom-color: var(--celadon); }

/* ---------- Hero ---------- */

.hero { background: var(--paper-2); border-bottom: 1px solid var(--rule); }

.hero .wrap {
  display: grid;
  grid-template-columns: 1fr 250px;
  gap: 3.5rem;
  align-items: start;
  padding-top: 4.25rem;
  padding-bottom: 4.25rem;
}

.hero h1 {
  font-size: clamp(2.4rem, 5.4vw, 3.5rem);
  line-height: 1.06;
  letter-spacing: -0.028em;
  margin-bottom: 0.75rem;
}

.hero-role {
  font-family: var(--display);
  font-size: 0.97rem;
  color: var(--ink-2);
  margin-bottom: 0.15rem;
}
.hero-role strong { color: var(--ink); font-weight: 600; }

.hero-thesis {
  font-family: var(--body);
  font-size: 1.3rem;
  line-height: 1.52;
  color: var(--ink);
  max-width: 40ch;
  margin: 1.6rem 0 1.75rem;
}

.hero-areas {
  font-family: var(--mono);
  font-size: 0.74rem;
  letter-spacing: 0.05em;
  color: var(--ink-3);
  margin-bottom: 1.9rem;
  line-height: 1.9;
}
.hero-areas span { color: var(--celadon-2); padding: 0 0.35rem; }

.linkrow { display: flex; flex-wrap: wrap; gap: 0.55rem; }

.linkrow a {
  font-family: var(--mono);
  font-size: 0.78rem;
  letter-spacing: 0.02em;
  color: var(--ink-2);
  border: 1px solid var(--rule);
  background: var(--paper);
  padding: 0.42rem 0.85rem;
  border-radius: 2px;
  transition: border-color 0.15s ease, color 0.15s ease, background 0.15s ease;
}
.linkrow a:hover {
  text-decoration: none;
  color: var(--celadon);
  border-color: var(--celadon-2);
  background: var(--celadon-wash);
}

.portrait {
  width: 100%;
  aspect-ratio: 4 / 5;
  object-fit: cover;
  border: 1px solid var(--rule);
  background: var(--celadon-wash);
  display: block;
}

.portrait-note {
  font-family: var(--mono);
  font-size: 0.68rem;
  color: var(--ink-3);
  margin-top: 0.6rem;
  line-height: 1.5;
}

/* ---------- The metadata rail ---------- */

.rail-list { position: relative; margin: 0; padding: 0; list-style: none; }

.rail-list::before {
  content: "";
  position: absolute;
  left: var(--gutter);
  top: 1.35rem;
  bottom: 1.35rem;
  border-left: 1px solid var(--rule);
}

.rail-item {
  position: relative;
  display: grid;
  grid-template-columns: var(--gutter) 1fr;
  column-gap: var(--gap);
  padding: 0.6rem 0;
}

.rail-item::before {
  content: "";
  position: absolute;
  left: var(--gutter);
  top: 1.02rem;
  width: 7px;
  height: 7px;
  margin-left: -3.5px;
  border-radius: 50%;
  background: var(--celadon);
  box-shadow: 0 0 0 3px var(--paper);
}

.rail-key {
  font-family: var(--mono);
  font-size: 0.76rem;
  line-height: 1.45;
  letter-spacing: 0.01em;
  text-align: right;
  color: var(--ink-3);
  padding-top: 0.3rem;
  padding-right: 0.15rem;
}

.rail-body { color: var(--ink-2); max-width: 74ch; }
.rail-body strong { color: var(--ink); font-weight: 600; }
.rail-body em { color: var(--ink-2); }
.rail-title { color: var(--ink); }

.rail-method {
  display: block;
  margin-top: 0.3rem;
  font-family: var(--mono);
  font-size: 0.71rem;
  letter-spacing: 0.02em;
  color: var(--celadon);
}

/* Work in progress: same structure, projected rail */
.rail-list--projected::before {
  border-left-style: dashed;
  border-left-color: var(--celadon-2);
}
.rail-list--projected .rail-item::before {
  background: var(--paper);
  border: 1px solid var(--celadon-2);
}
.rail-list--projected .rail-key { color: var(--celadon); }

.rail-note {
  font-family: var(--mono);
  font-size: 0.72rem;
  letter-spacing: 0.02em;
  color: var(--ink-3);
  margin: 0 0 1rem;
  padding-left: calc(var(--gutter) + var(--gap));
}

.subhead {
  font-family: var(--mono);
  font-size: 0.72rem;
  font-weight: 500;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--ink-3);
  margin: 2.6rem 0 0.9rem;
  padding-bottom: 0.5rem;
  border-bottom: 1px solid var(--rule-soft);
}
.subhead:first-child { margin-top: 0; }

/* ---------- Research area blocks ---------- */

.areas { display: grid; gap: 1px; background: var(--rule); border: 1px solid var(--rule); }

.area {
  background: var(--paper);
  padding: 1.6rem 1.7rem;
}
.area .area-no {
  font-family: var(--mono);
  font-size: 0.72rem;
  letter-spacing: 0.1em;
  color: var(--celadon-2);
  display: block;
  margin-bottom: 0.55rem;
}
.area p { color: var(--ink-2); font-size: 0.97rem; margin: 0; }
.area h3 { margin-bottom: 0.5rem; }

@media (min-width: 860px) {
  .areas { grid-template-columns: repeat(3, 1fr); }
}

.tags { display: flex; flex-wrap: wrap; gap: 0.4rem; margin-top: 1rem; }
.tag {
  font-family: var(--mono);
  font-size: 0.7rem;
  letter-spacing: 0.02em;
  color: var(--ink-2);
  background: var(--paper-2);
  border: 1px solid var(--rule);
  border-radius: 2px;
  padding: 0.22rem 0.55rem;
}

/* ---------- Utility ---------- */

.more {
  font-family: var(--mono);
  font-size: 0.8rem;
  letter-spacing: 0.02em;
  display: inline-block;
  margin-top: 1.8rem;
}
.more::after { content: " →"; }
.more:hover { text-decoration: none; border-bottom: 1px solid var(--celadon); }

.two-col { display: grid; gap: 2.5rem; }
@media (min-width: 860px) { .two-col { grid-template-columns: 1fr 1fr; gap: 3rem; } }

.callout {
  background: var(--celadon-wash);
  border-left: 2px solid var(--celadon);
  padding: 1.4rem 1.6rem;
  margin: 0 0 2rem;
}
.callout p { color: var(--ink-2); margin-bottom: 0; }
.callout p + p { margin-top: 0.9rem; }

.plain-list { margin: 0; padding-left: 1.15rem; color: var(--ink-2); }
.plain-list li { margin-bottom: 0.4rem; }

/* ---------- Page header (interior pages) ---------- */

.page-head { background: var(--paper-2); border-bottom: 1px solid var(--rule); }
.page-head .wrap { padding-top: 3.4rem; padding-bottom: 3.4rem; }
.page-head h1 {
  font-size: clamp(2rem, 4.2vw, 2.7rem);
  line-height: 1.1;
  letter-spacing: -0.026em;
  margin-bottom: 0.9rem;
}

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

.site-footer {
  border-top: 1px solid var(--rule);
  background: var(--paper-2);
  padding: 2.6rem 0;
  margin-top: 0;
}
.site-footer .wrap {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 1.5rem;
  flex-wrap: wrap;
}
.site-footer p,
.site-footer .foot-links {
  font-family: var(--mono);
  font-size: 0.74rem;
  letter-spacing: 0.02em;
  color: var(--ink-3);
  margin: 0;
}
.foot-links { display: flex; gap: 1.2rem; flex-wrap: wrap; }
.foot-links a { color: var(--ink-2); }
.foot-links a:hover { color: var(--celadon); }

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

@media (max-width: 900px) {
  .hero .wrap { grid-template-columns: 1fr; gap: 2.5rem; }
  .portrait { max-width: 210px; }
}

@media (max-width: 700px) {
  body { font-size: 16px; }
  .wrap { padding: 0 20px; }
  .section { padding: 3.2rem 0; }
  h2 { font-size: 1.6rem; }

  .site-header .wrap { min-height: 0; padding-top: 0.7rem; padding-bottom: 0.7rem; }
  .nav { gap: 1.15rem; width: 100%; }

  .rail-list::before { display: none; }
  .rail-item { grid-template-columns: 1fr; row-gap: 0.15rem; padding: 0.85rem 0; }
  .rail-item::before { display: none; }
  .rail-item + .rail-item { border-top: 1px solid var(--rule-soft); }
  .rail-key { text-align: left; padding-top: 0; color: var(--celadon); }
  .rail-note { padding-left: 0; }
}

@media print {
  .site-header, .site-footer, .linkrow, .portrait, .portrait-note { display: none; }
  body { background: #fff; font-size: 11pt; }
  .section { padding: 1.2rem 0; }
}