/* ==========================================================================
   Alp Simsek — personal site
   Hand-written CSS. No frameworks, no build step beyond build.py.
   ========================================================================== */

/* ---------- tokens: light (default) ---------- */
:root {
  --bg:        #fbfaf7;
  --bg-tint:   #f4f1ea;
  --surface:   #ffffff;
  --ink:       #1c1b19;
  --ink-soft:  #45423e;
  --muted:     #7a746c;
  --rule:      #e4dfd5;
  --rule-soft: #eeeae2;
  --accent:    #00356b;   /* Yale blue */
  --accent-2:  #0b5c8a;
  --pill-bg:   #ffffff;
  --pill-ink:  #4a4640;
  --shadow:    0 1px 2px rgba(28,27,25,.05), 0 8px 24px -16px rgba(28,27,25,.28);

  --serif: "Newsreader", Charter, "Iowan Old Style", Georgia, "Times New Roman", serif;
  --sans:  "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif;

  --measure: 42rem;
  --page:    64rem;
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg:        #14151a;
    --bg-tint:   #1a1c22;
    --surface:   #1b1d23;
    --ink:       #eae7e2;
    --ink-soft:  #c6c2bb;
    --muted:     #948e85;
    --rule:      #2c2f37;
    --rule-soft: #24272e;
    --accent:    #8fb8dd;
    --accent-2:  #a9cbe8;
    --pill-bg:   #1f2228;
    --pill-ink:  #bdb8b0;
    --shadow:    0 1px 2px rgba(0,0,0,.4), 0 8px 24px -16px rgba(0,0,0,.7);
  }
}

:root[data-theme="dark"] {
  --bg:        #14151a;
  --bg-tint:   #1a1c22;
  --surface:   #1b1d23;
  --ink:       #eae7e2;
  --ink-soft:  #c6c2bb;
  --muted:     #948e85;
  --rule:      #2c2f37;
  --rule-soft: #24272e;
  --accent:    #8fb8dd;
  --accent-2:  #a9cbe8;
  --pill-bg:   #1f2228;
  --pill-ink:  #bdb8b0;
  --shadow:    0 1px 2px rgba(0,0,0,.4), 0 8px 24px -16px rgba(0,0,0,.7);
}

/* ---------- base ---------- */
* { box-sizing: border-box; }

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

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--serif);
  font-size: 1.0625rem;
  line-height: 1.62;
  font-optical-sizing: auto;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

a { color: var(--accent); text-decoration: none; }
a:hover { color: var(--accent-2); text-decoration: underline; text-underline-offset: .18em; }

p { margin: 0 0 1em; }
em { font-style: italic; }
img { max-width: 100%; display: block; }

::selection { background: color-mix(in srgb, var(--accent) 18%, transparent); }

/* ---------- layout ---------- */
.wrap { max-width: var(--page); margin: 0 auto; padding: 0 1.5rem; }
.col  { max-width: var(--measure); }

/* ---------- header ---------- */
.site-header {
  position: sticky; top: 0; z-index: 20;
  background: color-mix(in srgb, var(--bg) 88%, transparent);
  backdrop-filter: saturate(1.4) blur(10px);
  -webkit-backdrop-filter: saturate(1.4) blur(10px);
  border-bottom: 1px solid var(--rule-soft);
}
.site-header .wrap {
  display: flex; align-items: baseline; justify-content: space-between;
  gap: 1.5rem; padding-top: .85rem; padding-bottom: .85rem;
}
.brand {
  font-family: var(--serif);
  font-size: 1.0625rem; font-weight: 500; letter-spacing: .01em;
  color: var(--ink);
}
.brand:hover { text-decoration: none; color: var(--accent); }

nav.site-nav { display: flex; gap: 1.35rem; flex-wrap: wrap; }
nav.site-nav a {
  font-family: var(--sans);
  font-size: .8125rem; font-weight: 450; letter-spacing: .02em;
  color: var(--muted);
  padding-bottom: 2px;
  border-bottom: 1px solid transparent;
}
nav.site-nav a:hover { color: var(--ink); text-decoration: none; border-bottom-color: var(--rule); }
nav.site-nav a[aria-current="page"] { color: var(--ink); border-bottom-color: var(--accent); }
nav.site-nav a .ext { font-size: .7em; opacity: .55; margin-left: .18em; }

/* ---------- hero ---------- */
.hero { padding: 3.75rem 0 2.5rem; }
.hero-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 15rem;
  gap: 3rem;
  align-items: start;
}
.hero h1 {
  font-family: var(--serif);
  font-size: clamp(2.1rem, 1.3rem + 2.6vw, 3.1rem);
  font-weight: 400;
  line-height: 1.08;
  letter-spacing: -.018em;
  margin: 0 0 .55rem;
}
.hero .role {
  font-family: var(--sans);
  font-size: .9375rem; font-weight: 450;
  color: var(--ink-soft);
  margin: 0 0 .25rem;
}
.hero .role .sep { color: var(--rule); margin: 0 .5rem; }
.hero .tagline {
  font-size: 1.0625rem; color: var(--muted); font-style: italic;
  margin: 0 0 1.75rem;
}

.portrait {
  width: 100%;
  height: auto;          /* beat the img height attribute so aspect-ratio wins */
  aspect-ratio: 4 / 5;
  object-fit: cover;
  object-position: 50% 14%;
  border-radius: 3px;
  box-shadow: var(--shadow);
  filter: saturate(.96);
}

/* ---------- prose ---------- */
.prose { max-width: var(--measure); }
.prose p { color: var(--ink-soft); }
.prose p:last-child { margin-bottom: 0; }

/* ---------- quick links ---------- */
.quicklinks { display: flex; flex-wrap: wrap; gap: .5rem; margin: 1.75rem 0 0; }
.quicklinks a {
  font-family: var(--sans);
  font-size: .8125rem; font-weight: 500; letter-spacing: .01em;
  color: var(--ink);
  background: var(--pill-bg);
  border: 1px solid var(--rule);
  border-radius: 999px;
  padding: .4rem .9rem;
  transition: border-color .15s ease, transform .15s ease;
}
.quicklinks a:hover {
  text-decoration: none;
  border-color: var(--accent);
  color: var(--accent);
  transform: translateY(-1px);
}

/* ---------- roles list under portrait ---------- */
.sidecard {
  font-family: var(--sans);
  font-size: .8125rem;
  line-height: 1.6;
  color: var(--muted);
  margin-top: 1rem;
}
.sidecard li { margin-bottom: .5rem; list-style: none; }
.sidecard ul { margin: 0; padding: 0; }
.sidecard em { font-style: italic; }

/* ---------- section headings ---------- */
.section { padding: 2.5rem 0; border-top: 1px solid var(--rule-soft); }
.section:first-of-type { border-top: 0; }

h2.section-title {
  font-family: var(--sans);
  font-size: .75rem;
  font-weight: 600;
  letter-spacing: .1em;
  text-transform: uppercase;
  color: var(--muted);
  margin: 0 0 1.75rem;
}

h3.group-title {
  max-width: 46rem;
  font-family: var(--serif);
  font-size: 1.25rem; font-weight: 500; letter-spacing: -.005em;
  margin: 2.75rem 0 1.25rem;
  padding-bottom: .4rem;
  border-bottom: 1px solid var(--rule);
}
h3.group-title:first-child { margin-top: 0; }

.page-title {
  font-family: var(--serif);
  font-size: clamp(1.9rem, 1.4rem + 1.6vw, 2.5rem);
  font-weight: 400; letter-spacing: -.015em;
  margin: 3rem 0 .5rem;
}
.page-intro { color: var(--muted); max-width: var(--measure); margin: 0 0 2.5rem; }

/* ---------- paper list ---------- */
.papers { list-style: none; margin: 0; padding: 0; max-width: 46rem; }

.paper {
  padding: 1.15rem 0 1.15rem 1.1rem;
  margin-left: -1.1rem;
  border-bottom: 1px solid var(--rule-soft);
  border-left: 2px solid transparent;
  transition: border-left-color .18s ease, background .18s ease;
}
.paper:last-child { border-bottom: 0; }
.paper:hover { border-left-color: var(--accent); background: var(--bg-tint); }

.paper-title {
  font-family: var(--serif);
  font-size: 1.1875rem;
  font-weight: 500;
  line-height: 1.32;
  letter-spacing: -.006em;
  margin: 0 0 .3rem;
  color: var(--ink);
}
.paper-title a { color: inherit; }
.paper-title a:hover { color: var(--accent); text-decoration: none; }

.paper-meta {
  font-family: var(--sans);
  font-size: .84375rem;
  color: var(--muted);
  margin: 0 0 .55rem;
}
.paper-meta .outlet { font-style: italic; color: var(--ink-soft); }
.paper-meta .dot { margin: 0 .45rem; opacity: .5; }

.paper-note {
  font-family: var(--sans);
  font-size: .8125rem;
  color: var(--muted);
  margin: 0 0 .55rem;
}
.paper-note em { font-style: italic; }

/* link pills */
.paper-links { display: flex; flex-wrap: wrap; gap: .35rem; align-items: center; }
.paper-links a, .abstract-toggle {
  font-family: var(--sans);
  font-size: .75rem; font-weight: 500; letter-spacing: .015em;
  color: var(--pill-ink);
  background: var(--pill-bg);
  border: 1px solid var(--rule);
  border-radius: 4px;
  padding: .2rem .55rem;
  white-space: nowrap;
  transition: border-color .15s ease, color .15s ease;
}
.paper-links a:hover { color: var(--accent); border-color: var(--accent); text-decoration: none; }

/* abstract disclosure */
details.abstract { margin-top: .55rem; }
details.abstract > summary {
  list-style: none;
  display: inline-block;
  cursor: pointer;
  font-family: var(--sans);
  font-size: .75rem; font-weight: 500; letter-spacing: .015em;
  color: var(--pill-ink);
  background: var(--pill-bg);
  border: 1px solid var(--rule);
  border-radius: 4px;
  padding: .2rem .55rem;
  user-select: none;
  transition: border-color .15s ease, color .15s ease;
}
details.abstract > summary::-webkit-details-marker { display: none; }
details.abstract > summary:hover { color: var(--accent); border-color: var(--accent); }
details.abstract > summary::after { content: " ＋"; font-size: .8em; opacity: .6; }
details.abstract[open] > summary::after { content: " －"; }
details.abstract[open] > summary { color: var(--accent); border-color: var(--accent); }
.abstract-body {
  margin-top: .85rem;
  padding-left: .9rem;
  border-left: 2px solid var(--rule);
  font-size: .96875rem;
  line-height: 1.6;
  color: var(--ink-soft);
  max-width: var(--measure);
}

/* keep the abstract row on its own line under the pills */
.paper-actions { display: flex; flex-wrap: wrap; gap: .35rem; align-items: center; }

/* ---------- teaching ---------- */
.courses { list-style: none; margin: 0; padding: 0; }
.course {
  display: grid;
  grid-template-columns: 7.5rem minmax(0,1fr);
  gap: 1rem;
  padding: .85rem 0;
  border-bottom: 1px solid var(--rule-soft);
}
.course:last-child { border-bottom: 0; }
.course .code {
  font-family: var(--sans);
  font-size: .8125rem; font-weight: 500;
  color: var(--muted);
  padding-top: .18rem;
}
.course .name { font-size: 1.0625rem; font-weight: 500; margin: 0 0 .15rem; }
.course .detail { font-family: var(--sans); font-size: .8125rem; color: var(--muted); }
.course .detail a { font-size: inherit; }

.students-group { margin-bottom: 2rem; }
.students-group h4 {
  font-family: var(--sans);
  font-size: .8125rem; font-weight: 600; letter-spacing: .02em;
  color: var(--ink);
  margin: 0 0 .5rem;
}
.students-group p { color: var(--ink-soft); margin: 0; }

/* ---------- honors ---------- */
.honors { list-style: none; margin: 0; padding: 0; max-width: var(--measure); }
.honors li {
  padding: .45rem 0 .45rem 1.1rem;
  position: relative;
  color: var(--ink-soft);
  font-size: 1rem;
}
.honors li::before {
  content: "";
  position: absolute; left: 0; top: 1.05em;
  width: .35rem; height: 1px; background: var(--muted);
}

/* ---------- contact ---------- */
.contact-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(14rem, 1fr));
  gap: 2rem;
  max-width: var(--measure);
}
.contact-grid h4 {
  font-family: var(--sans);
  font-size: .75rem; font-weight: 600; letter-spacing: .08em; text-transform: uppercase;
  color: var(--muted);
  margin: 0 0 .5rem;
}
.contact-grid p { color: var(--ink-soft); margin: 0; }

/* ---------- footer ---------- */
.site-footer {
  border-top: 1px solid var(--rule-soft);
  margin-top: 3rem;
  padding: 2rem 0 3rem;
  font-family: var(--sans);
  font-size: .8125rem;
  color: var(--muted);
}
.site-footer .wrap { display: flex; justify-content: space-between; gap: 1.5rem; flex-wrap: wrap; }
.site-footer a { color: var(--muted); }
.site-footer a:hover { color: var(--accent); }

/* ---------- responsive ---------- */
@media (max-width: 46rem) {
  .hero { padding: 2.25rem 0 1.5rem; }
  .hero-grid { grid-template-columns: 1fr; gap: 1.75rem; }
  .portrait-wrap { max-width: 11rem; }
  .course { grid-template-columns: 1fr; gap: .1rem; }
  .course .code { padding-top: 0; }
  .site-header .wrap { flex-direction: column; align-items: flex-start; gap: .5rem; }
  nav.site-nav { gap: 1.1rem; }
}

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

/* ---------- print ---------- */
@media print {
  .site-header, .site-footer, .quicklinks { display: none; }
  body { background: #fff; color: #000; }
  details.abstract[open] > summary { display: none; }
}

/* ---------- in-page jump nav (research) ---------- */
.jumps {
  display: flex; flex-wrap: wrap; gap: .4rem;
  max-width: 46rem;
  margin: 0 0 2.5rem;
  padding-bottom: 1.75rem;
  border-bottom: 1px solid var(--rule-soft);
}
.jumps a {
  font-family: var(--sans);
  font-size: .75rem; font-weight: 500; letter-spacing: .015em;
  color: var(--pill-ink);
  background: var(--pill-bg);
  border: 1px solid var(--rule);
  border-radius: 999px;
  padding: .25rem .7rem;
  transition: border-color .15s ease, color .15s ease;
}
.jumps a:hover { color: var(--accent); border-color: var(--accent); text-decoration: none; }

/* offset anchors so the sticky header doesn't cover the heading */
h3.group-title { scroll-margin-top: 5rem; }

/* keep teaching content on the same measure as the paper lists */
.courses, .students-group, .honors { max-width: 46rem; }

/* ---------- subheading inside a research group ---------- */
h4.subgroup-title {
  font-family: var(--sans);
  font-size: .75rem;
  font-weight: 600;
  letter-spacing: .08em;
  text-transform: uppercase;
  color: var(--muted);
  max-width: 46rem;
  margin: 2rem 0 .75rem;
}
h4.subgroup-title:first-of-type { margin-top: 0; }