/* ==========================================================
   Tolga Ergen — personal site
   ========================================================== */

:root {
  --bg: #fbfbf9;
  --bg-alt: #f3f3ef;
  --surface: #ffffff;
  --text: #1b1d21;
  --text-2: #4a4f59;
  --text-3: #7a808c;
  --line: #e4e4de;
  --accent: #2c4fc9;
  --accent-soft: rgba(44, 79, 201, 0.08);
  --gold: #a8740f;
  --gold-soft: rgba(201, 145, 26, 0.12);
  --shadow: 0 1px 2px rgba(20, 22, 30, 0.04), 0 8px 24px rgba(20, 22, 30, 0.06);
  --radius: 14px;
  --serif: "Source Serif 4", Georgia, "Times New Roman", serif;
  --sans: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  --maxw: 1040px;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0f1115;
    --bg-alt: #151820;
    --surface: #181b23;
    --text: #e9eaee;
    --text-2: #b4b8c2;
    --text-3: #868b97;
    --line: #262a35;
    --accent: #8aa8ff;
    --accent-soft: rgba(138, 168, 255, 0.12);
    --gold: #e6b450;
    --gold-soft: rgba(230, 180, 80, 0.14);
    --shadow: 0 1px 2px rgba(0, 0, 0, 0.3), 0 8px 24px rgba(0, 0, 0, 0.25);
  }
}

*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: 80px; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--sans);
  font-size: 16px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}
img { max-width: 100%; display: block; }
a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; text-underline-offset: 3px; }
::selection { background: var(--accent-soft); }

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

/* ---------- Nav ---------- */
.nav {
  position: sticky; top: 0; z-index: 50;
  background: color-mix(in srgb, var(--bg) 82%, transparent);
  backdrop-filter: saturate(160%) blur(12px);
  -webkit-backdrop-filter: saturate(160%) blur(12px);
  border-bottom: 1px solid transparent;
  transition: border-color .2s;
}
.nav.scrolled { border-bottom-color: var(--line); }
.nav .wrap { display: flex; align-items: center; justify-content: space-between; height: 64px; gap: 16px; }
.brand { font-family: var(--serif); font-weight: 600; font-size: 20px; color: var(--text); letter-spacing: -0.01em; white-space: nowrap; }
.brand:hover { text-decoration: none; }
.nav ul { list-style: none; display: flex; gap: 4px; margin: 0; padding: 0; overflow-x: auto; scrollbar-width: none; }
.nav ul::-webkit-scrollbar { display: none; }
.nav a.nl { display: block; padding: 6px 12px; border-radius: 8px; color: var(--text-2); font-size: 14.5px; font-weight: 500; white-space: nowrap; }
.nav a.nl:hover { background: var(--bg-alt); color: var(--text); text-decoration: none; }
.nav a.nl.active { color: var(--text); background: var(--bg-alt); }

/* ---------- Hero ---------- */
.hero { position: relative; padding: 72px 0 56px; overflow: hidden; }
.hero::before {
  content: ""; position: absolute; inset: -40% -10% auto auto; width: 720px; height: 720px;
  background: radial-gradient(closest-side, var(--accent-soft), transparent 70%);
  pointer-events: none;
}
.hero .wrap { position: relative; display: grid; grid-template-columns: 260px 1fr; gap: 56px; align-items: center; }
.portrait { position: relative; }
.portrait img {
  width: 260px; height: 300px; object-fit: cover; object-position: center 20%;
  border-radius: 20px; box-shadow: var(--shadow);
  border: 1px solid var(--line);
}
.eyebrow { font-size: 13px; font-weight: 600; letter-spacing: .12em; text-transform: uppercase; color: var(--accent); margin: 0 0 10px; }
.hero h1 { font-family: var(--serif); font-weight: 600; font-size: clamp(38px, 6vw, 56px); line-height: 1.05; letter-spacing: -0.02em; margin: 0 0 14px; }
.hero .role { font-size: 18px; color: var(--text-2); margin: 0 0 22px; }
.hero .role strong { color: var(--text); font-weight: 600; }
.hero p.lead { color: var(--text-2); margin: 0 0 26px; max-width: 620px; }

.socials { display: flex; flex-wrap: wrap; gap: 10px; }
.btn {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 9px 16px; border-radius: 999px; font-size: 14.5px; font-weight: 500;
  border: 1px solid var(--line); background: var(--surface); color: var(--text);
  transition: transform .15s, border-color .15s, box-shadow .15s, background .15s;
}
.btn:hover { text-decoration: none; border-color: var(--accent); transform: translateY(-1px); box-shadow: var(--shadow); }
.btn i { font-size: 15px; color: var(--text-2); }
.btn.primary { background: var(--text); color: var(--bg); border-color: var(--text); }
.btn.primary i { color: var(--bg); }

/* ---------- Sections ---------- */
section.block { padding: 56px 0; border-top: 1px solid var(--line); }
.section-head { display: flex; align-items: baseline; justify-content: space-between; gap: 16px; margin-bottom: 28px; }
h2.title { font-family: var(--serif); font-weight: 600; font-size: 30px; letter-spacing: -0.015em; margin: 0; }
.section-head .sub { color: var(--text-3); font-size: 14.5px; }
.prose p { color: var(--text-2); margin: 0 0 16px; max-width: 760px; }
.prose p:last-child { margin-bottom: 0; }

/* Interests chips */
.interests { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; margin-top: 28px; }
.interest {
  background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 20px; box-shadow: var(--shadow);
}
.interest i { font-size: 20px; color: var(--accent); background: var(--accent-soft); width: 40px; height: 40px; border-radius: 10px; display: grid; place-items: center; margin-bottom: 12px; }
.interest h3 { font-size: 16px; margin: 0 0 6px; font-weight: 600; }
.interest p { margin: 0; color: var(--text-2); font-size: 14.5px; line-height: 1.55; }

/* Honors */
.honors { display: grid; grid-template-columns: repeat(4, 1fr); gap: 14px; }
.honor {
  border: 1px solid var(--line); border-radius: var(--radius); padding: 18px;
  background: var(--surface);
}
.honor .yr { font-size: 12.5px; font-weight: 600; color: var(--gold); background: var(--gold-soft); padding: 2px 9px; border-radius: 999px; display: inline-block; margin-bottom: 10px; }
.honor h3 { font-size: 15px; margin: 0 0 4px; font-weight: 600; line-height: 1.35; }
.honor p { font-size: 13.5px; color: var(--text-3); margin: 0; line-height: 1.45; }

/* News */
.news { list-style: none; margin: 0; padding: 0; }
.news li { display: grid; grid-template-columns: 96px 1fr; gap: 20px; padding: 13px 0; border-bottom: 1px dashed var(--line); }
.news li:last-child { border-bottom: 0; }
.news .date { font-size: 13.5px; font-weight: 600; color: var(--text-3); font-variant-numeric: tabular-nums; padding-top: 1px; }
.news .txt { color: var(--text-2); }
.news .txt strong { color: var(--text); font-weight: 600; }
.news li.hl .date { color: var(--gold); }
details.more summary {
  cursor: pointer; list-style: none; margin-top: 14px;
  display: inline-flex; align-items: center; gap: 8px; font-size: 14.5px; font-weight: 500; color: var(--accent);
}
details.more summary::-webkit-details-marker { display: none; }
details.more summary i { transition: transform .2s; font-size: 12px; }
details.more[open] summary i { transform: rotate(180deg); }
details.more[open] summary .lbl-open { display: none; }
details.more:not([open]) summary .lbl-close { display: none; }

/* Timeline (experience / education / teaching) */
.two-col { display: grid; grid-template-columns: 1fr 1fr; gap: 48px; }
h3.col-title { font-size: 13px; font-weight: 600; letter-spacing: .12em; text-transform: uppercase; color: var(--text-3); margin: 0 0 18px; }
.tl { list-style: none; margin: 0; padding: 0; }
.tl li { display: grid; grid-template-columns: 52px 1fr; gap: 16px; align-items: center; padding: 12px 0; }
.tl .logo {
  width: 52px; height: 52px; border-radius: 12px; background: #fff; border: 1px solid var(--line);
  display: grid; place-items: center; overflow: hidden; padding: 6px;
}
.tl .logo img { width: 100%; height: 100%; object-fit: contain; }
.tl .what { font-weight: 600; line-height: 1.35; }
.tl .where { color: var(--text-2); font-size: 14.5px; }
.tl .when { color: var(--text-3); font-size: 13.5px; font-variant-numeric: tabular-nums; }

.courses { list-style: none; margin: 0; padding: 0; display: grid; gap: 10px; }
.courses li { background: var(--surface); border: 1px solid var(--line); border-radius: 12px; padding: 14px 16px; display: grid; grid-template-columns: 1fr auto; gap: 4px 16px; }
.courses .code { font-weight: 600; }
.courses .name { color: var(--text-2); font-size: 14.5px; grid-column: 1 / -1; }
.courses .term { color: var(--text-3); font-size: 13px; text-align: right; }
.courses .inst { color: var(--text-3); font-size: 12.5px; font-weight: 600; letter-spacing: .06em; text-transform: uppercase; }

.service { display: flex; flex-wrap: wrap; gap: 8px; }
.tag { font-size: 13px; padding: 4px 11px; border-radius: 999px; background: var(--bg-alt); color: var(--text-2); border: 1px solid var(--line); }

/* ---------- Publications ---------- */
.page-head { padding: 64px 0 32px; }
.page-head h1 { font-family: var(--serif); font-weight: 600; font-size: clamp(34px, 5vw, 46px); letter-spacing: -0.02em; margin: 0 0 10px; }
.page-head p { color: var(--text-2); margin: 0; max-width: 680px; }

.toolbar { position: sticky; top: 64px; z-index: 20; background: var(--bg); padding: 14px 0; border-bottom: 1px solid var(--line); margin-bottom: 8px; display: flex; flex-wrap: wrap; gap: 10px; align-items: center; justify-content: space-between; }
.filters { display: flex; flex-wrap: wrap; gap: 8px; }
.chip {
  font: inherit; font-size: 14px; font-weight: 500; cursor: pointer;
  padding: 7px 14px; border-radius: 999px; border: 1px solid var(--line);
  background: var(--surface); color: var(--text-2); transition: all .15s;
}
.chip:hover { border-color: var(--text-3); color: var(--text); }
.chip.on { background: var(--text); color: var(--bg); border-color: var(--text); }
.chip .n { opacity: .6; margin-left: 4px; font-variant-numeric: tabular-nums; }
.search { position: relative; }
.search i { position: absolute; left: 12px; top: 50%; transform: translateY(-50%); color: var(--text-3); font-size: 13px; }
.search input {
  font: inherit; font-size: 14px; width: 240px; padding: 8px 12px 8px 34px; border-radius: 999px;
  border: 1px solid var(--line); background: var(--surface); color: var(--text); outline: none;
}
.search input:focus { border-color: var(--accent); box-shadow: 0 0 0 3px var(--accent-soft); }

.pubs { list-style: none; margin: 0; padding: 0; }
.pub {
  display: grid; grid-template-columns: 200px 1fr; gap: 28px; padding: 26px 0;
  border-bottom: 1px solid var(--line);
}
.pub[hidden] { display: none; }
.pub .thumb {
  width: 200px; aspect-ratio: 4 / 3; border-radius: 12px; overflow: hidden;
  background: #fff; border: 1px solid var(--line); padding: 8px;
  transition: transform .25s, box-shadow .25s;
}
.pub:hover .thumb { transform: translateY(-2px); box-shadow: var(--shadow); }
.pub .thumb img { width: 100%; height: 100%; object-fit: contain; }
.pub h3 { font-family: var(--serif); font-size: 19px; font-weight: 600; line-height: 1.35; margin: 0 0 6px; letter-spacing: -0.005em; }
.pub h3 a { color: var(--text); }
.pub h3 a:hover { color: var(--accent); text-decoration: none; }
.pub .authors { color: var(--text-2); font-size: 14.5px; margin: 0 0 10px; }
.pub .authors b { color: var(--text); font-weight: 600; }
.pub .meta { display: flex; flex-wrap: wrap; gap: 8px; align-items: center; margin-bottom: 12px; }
.venue { font-size: 13px; font-weight: 600; padding: 3px 10px; border-radius: 6px; background: var(--accent-soft); color: var(--accent); }
.venue.pre { background: var(--bg-alt); color: var(--text-3); }
.award { font-size: 13px; font-weight: 600; padding: 3px 10px; border-radius: 6px; background: var(--gold-soft); color: var(--gold); display: inline-flex; gap: 6px; align-items: center; }
.pub .links { display: flex; flex-wrap: wrap; gap: 8px; margin-bottom: 10px; }
.pub .links a {
  font-size: 13px; font-weight: 500; padding: 4px 11px; border-radius: 8px;
  border: 1px solid var(--line); color: var(--text-2); display: inline-flex; gap: 6px; align-items: center;
}
.pub .links a:hover { border-color: var(--accent); color: var(--accent); text-decoration: none; }
.pub .kws { display: flex; flex-wrap: wrap; gap: 6px; }
.pub .kws span { font-size: 12.5px; color: var(--text-3); }
.pub .kws span:not(:last-child)::after { content: "·"; margin-left: 6px; }
.empty { text-align: center; color: var(--text-3); padding: 48px 0; }
.legend { font-size: 13px; color: var(--text-3); margin-top: 20px; }

/* ---------- Footer ---------- */
footer { border-top: 1px solid var(--line); padding: 32px 0 48px; color: var(--text-3); font-size: 14px; }
footer .wrap { display: flex; justify-content: space-between; flex-wrap: wrap; gap: 12px; }
footer a { color: var(--text-2); }

/* ---------- Reveal ---------- */
.reveal { opacity: 0; transform: translateY(14px); transition: opacity .6s ease, transform .6s ease; }
.reveal.in { opacity: 1; transform: none; }
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .reveal { opacity: 1; transform: none; transition: none; }
}

/* ---------- Responsive ---------- */
@media (max-width: 860px) {
  .hero .wrap { grid-template-columns: 1fr; gap: 32px; text-align: left; }
  .portrait img { width: 180px; height: 210px; }
  .interests { grid-template-columns: 1fr; }
  .honors { grid-template-columns: 1fr 1fr; }
  .two-col { grid-template-columns: 1fr; gap: 36px; }
  .pub { grid-template-columns: 1fr; gap: 14px; }
  .pub .thumb { width: 100%; max-width: 320px; }
  .search input { width: 100%; }
  .search { flex: 1 1 100%; }
}
@media (max-width: 560px) {
  .wrap { padding: 0 16px; }
  .hero { padding: 40px 0 40px; }
  .nav .brand { font-size: 18px; }
  .nav a.nl { padding: 6px 8px; font-size: 14px; }
  .nav li.opt { display: none; }
  .honors { grid-template-columns: 1fr; }
  .news li { grid-template-columns: 1fr; gap: 2px; }
  section.block { padding: 44px 0; }
  .toolbar { position: static; }
}

/* ---------- Current work ---------- */
section.now { background: linear-gradient(180deg, var(--bg-alt), var(--bg)); }
.focus { display: grid; grid-template-columns: repeat(3, 1fr); gap: 18px; }
.focus-card {
  position: relative; background: var(--surface); border: 1px solid var(--line); border-radius: 18px;
  padding: 24px 24px 20px; box-shadow: var(--shadow); display: flex; flex-direction: column;
  transition: transform .2s, border-color .2s;
}
.focus-card::before { content: ""; position: absolute; inset: 0 0 auto 0; height: 3px; border-radius: 18px 18px 0 0; background: var(--accent); opacity: .85; }
.focus-card:hover { transform: translateY(-3px); border-color: color-mix(in srgb, var(--accent) 40%, var(--line)); }
.focus-top { display: flex; justify-content: space-between; align-items: center; margin-bottom: 14px; }
.focus-top i { font-size: 20px; color: var(--accent); background: var(--accent-soft); width: 44px; height: 44px; border-radius: 12px; display: grid; place-items: center; }
.focus-top .num { font-family: var(--serif); font-size: 28px; color: var(--line); font-weight: 600; }
.focus-card h3 { font-family: var(--serif); font-size: 21px; font-weight: 600; margin: 0 0 8px; letter-spacing: -0.01em; }
.focus-card p { color: var(--text-2); font-size: 15px; line-height: 1.6; margin: 0 0 18px; flex: 1; }
.refs { display: flex; flex-wrap: wrap; gap: 6px; align-items: center; border-top: 1px dashed var(--line); padding-top: 14px; }
.refs span { font-size: 11.5px; font-weight: 600; letter-spacing: .1em; text-transform: uppercase; color: var(--text-3); margin-right: 4px; }
.refs a { font-size: 12.5px; padding: 3px 9px; border-radius: 999px; background: var(--bg-alt); border: 1px solid var(--line); color: var(--text-2); }
.refs a:hover { color: var(--accent); border-color: var(--accent); text-decoration: none; }
.refs a em { font-style: normal; color: var(--text-3); margin-left: 3px; }
.tl .desc { color: var(--text-2); font-size: 13.5px; line-height: 1.5; margin-top: 3px; }
.tl li { align-items: start; }
@media (max-width: 860px) { .focus { grid-template-columns: 1fr; } }