/* =========================================================================
   Giorgio Papitto — personal site
   Design tokens live here. Change these few variables to re-skin the site.
   ========================================================================= */

:root {
  /* Palette — light theme */
  --bg:           #fbfbf9;   /* warm near-white paper */
  --surface:      #ffffff;
  --ink:          #16161a;   /* primary text */
  --ink-soft:     #4a4a52;   /* secondary text */
  --ink-faint:    #8a8a94;   /* tertiary / meta */
  --line:         #e7e6e1;   /* hairline borders */
  --accent:       #3a4cff;   /* single restrained accent */
  --accent-soft:  rgba(58, 76, 255, 0.10);

  /* Type */
  --font-sans: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  --font-serif: "Newsreader", Georgia, "Times New Roman", serif;
  --font-mono: ui-monospace, "SF Mono", SFMono-Regular, Menlo, Consolas, "Liberation Mono", monospace;

  /* Rhythm */
  --maxw: 760px;
  --maxw-wide: 1080px;
  --gutter: clamp(1.25rem, 5vw, 3rem);
  --radius: 14px;
}

[data-theme="dark"] {
  --bg:           #0e0e11;
  --surface:      #161619;
  --ink:          #f1f0ec;
  --ink-soft:     #b6b5ad;
  --ink-faint:    #76757d;
  --line:         #26262b;
  --accent:       #8e9bff;
  --accent-soft:  rgba(142, 155, 255, 0.14);
}

/* ---------- Reset-ish ---------- */
*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  * { animation: none !important; transition: none !important; }
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--font-sans);
  font-size: 1.0625rem;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  transition: background-color .35s ease, color .35s ease;
}

img { max-width: 100%; display: block; }
a { color: inherit; }

::selection { background: var(--accent-soft); }

.skip-link {
  position: absolute; left: -999px; top: 0;
  background: var(--accent); color: #fff; padding: .6rem 1rem; z-index: 100;
  border-radius: 0 0 8px 0;
}
.skip-link:focus { left: 0; }

/* ---------- Header / nav ---------- */
.site-header {
  position: sticky; top: 0; z-index: 50;
  background: color-mix(in srgb, var(--bg) 82%, transparent);
  backdrop-filter: saturate(1.4) blur(12px);
  -webkit-backdrop-filter: saturate(1.4) blur(12px);
  border-bottom: 1px solid var(--line);
}
.nav {
  max-width: var(--maxw-wide);
  margin: 0 auto;
  padding: .85rem var(--gutter);
  display: flex; align-items: center; justify-content: space-between;
  gap: 1rem;
}
.nav__brand {
  display: inline-flex; align-items: center; gap: .55rem;
  text-decoration: none; font-weight: 600; letter-spacing: -0.01em;
  font-size: 1.02rem;
}
.nav__mark { color: #ff5a1f; font-size: .85em; }
.nav__menu {
  list-style: none; margin: 0; padding: 0;
  display: flex; align-items: center; gap: clamp(1rem, 2.4vw, 2rem);
}
.nav__menu a {
  text-decoration: none; color: var(--ink-soft);
  font-size: .95rem; font-weight: 500;
  position: relative; padding: .25rem 0;
  transition: color .2s ease;
}
.nav__menu a::after {
  content: ""; position: absolute; left: 0; right: 100%; bottom: -2px;
  height: 1.5px; background: var(--accent); transition: right .25s ease;
}
.nav__menu a:hover { color: var(--ink); }
.nav__menu a:hover::after,
.nav__menu a.is-active::after { right: 0; }
.nav__menu a.is-active { color: var(--ink); }

.nav__toggle { display: none; }

.theme-toggle {
  display: inline-flex; align-items: center; justify-content: center;
  width: 36px; height: 36px; border-radius: 50%;
  border: 1px solid var(--line); background: var(--surface);
  color: var(--ink); cursor: pointer; padding: 0;
  transition: border-color .2s ease, transform .2s ease;
}
.theme-toggle:hover { border-color: var(--accent); transform: rotate(-12deg); }
.theme-toggle__icon { width: 18px; height: 18px; fill: none; stroke: currentColor; stroke-width: 1.8; stroke-linecap: round; stroke-linejoin: round; }
.theme-toggle__icon--moon { display: none; }
[data-theme="dark"] .theme-toggle__icon--sun { display: none; }
[data-theme="dark"] .theme-toggle__icon--moon { display: block; }

/* ---------- Layout primitives ---------- */
main { display: block; }
.hero, .section {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: clamp(3.5rem, 9vw, 7rem) var(--gutter) 0;
}
.section:last-of-type { padding-bottom: clamp(3.5rem, 9vw, 7rem); }

/* ---------- Hero ---------- */
.hero {
  padding-top: clamp(4rem, 12vw, 9rem);
  padding-bottom: clamp(1rem, 4vw, 2rem);
}
.hero__eyebrow {
  font-family: var(--font-mono);
  font-size: .75rem; letter-spacing: .1em; text-transform: uppercase;
  color: var(--ink-faint); margin: 0 0 1.4rem;
}
.hero__title {
  font-family: var(--font-serif);
  font-weight: 400;
  font-size: clamp(2.4rem, 6.2vw, 4.1rem);
  line-height: 1.06;
  letter-spacing: -0.02em;
  margin: 0 0 1.6rem;
}
.hero__title em { font-style: italic; color: var(--accent); }
.hero__role {
  font-size: clamp(1rem, 1.5vw, 1.15rem);
  color: var(--ink-faint);
  margin: 0 0 1.6rem;
  letter-spacing: -0.005em;
}
.hero__lede {
  font-size: clamp(1.05rem, 1.6vw, 1.2rem);
  color: var(--ink-soft);
  max-width: 60ch;
  margin: 0 0 2.2rem;
}
.hero__actions { display: flex; flex-wrap: wrap; gap: .8rem; }

.btn {
  display: inline-flex; align-items: center; gap: .4rem;
  text-decoration: none; font-weight: 500; font-size: .98rem;
  padding: .72rem 1.4rem; border-radius: 999px;
  border: 1px solid transparent; cursor: pointer;
  transition: transform .15s ease, background-color .2s ease, border-color .2s ease, color .2s ease;
}
.btn:hover { transform: translateY(-2px); }
.btn--primary { background: var(--ink); color: var(--bg); }
.btn--primary:hover { background: var(--accent); }
.btn--ghost { border-color: var(--line); color: var(--ink); }
.btn--ghost:hover { border-color: var(--accent); color: var(--accent); }

/* ---------- Section heads ---------- */
.section__head {
  display: flex; align-items: baseline; gap: .9rem;
  margin-bottom: 1.8rem;
  padding-bottom: 1rem;
  border-bottom: 1px solid var(--line);
}
.section__index {
  font-family: var(--font-mono);
  font-size: .8rem; font-variant-numeric: tabular-nums;
  color: var(--accent); font-weight: 500; letter-spacing: .05em;
}
.section__title {
  font-family: var(--font-serif); font-weight: 500;
  font-size: clamp(1.6rem, 3.4vw, 2.2rem);
  letter-spacing: -0.015em; margin: 0;
}
.section__intro { color: var(--ink-soft); margin: 0 0 2rem; max-width: 60ch; }

.prose p { color: var(--ink-soft); margin: 0 0 1.2rem; max-width: 66ch; }
.prose p:last-child { margin-bottom: 0; }

/* ---------- Tags / focus strip ---------- */
.tags {
  list-style: none; margin: 1.8rem 0 0; padding: 0;
  display: flex; flex-wrap: wrap; gap: .5rem;
}
.tags li {
  font-family: var(--font-mono);
  font-size: .76rem; color: var(--ink-soft);
  border: 1px solid var(--line); border-radius: 999px;
  padding: .3rem .8rem; white-space: nowrap;
  transition: border-color .2s ease, color .2s ease;
}
.tags li:hover { border-color: var(--accent); color: var(--accent); }

/* ---------- Research cards ---------- */
.cards { display: grid; gap: 2rem; grid-template-columns: 1fr; }
@media (min-width: 720px) { .cards { grid-template-columns: repeat(3, 1fr); gap: 2.4rem; } }
.card {
  border-top: 1px solid var(--ink);
  padding-top: .9rem;
}
.card__title {
  font-size: 1.02rem; margin: 0 0 .55rem; letter-spacing: -0.01em;
  transition: color .2s ease;
}
.card:hover .card__title { color: var(--accent); }
.card__body { color: var(--ink-soft); font-size: .94rem; margin: 0; }

/* ---------- Publications ---------- */
.pub-group {
  font-family: var(--font-mono);
  font-size: .76rem; text-transform: uppercase; letter-spacing: .1em;
  color: var(--ink-faint); font-weight: 500;
  margin: 2.6rem 0 1rem;
}
.pub-group:first-of-type { margin-top: 0; }
.pubs { list-style: none; margin: 0; padding: 0; }
.pub {
  display: grid; grid-template-columns: 64px 1fr; gap: 1rem;
  padding: 1.4rem 0; border-top: 1px solid var(--line);
}
.pub:first-child { border-top: none; }
.pub__year {
  font-variant-numeric: tabular-nums; color: var(--ink-faint);
  font-size: .9rem; font-weight: 500; padding-top: .15rem;
}
.pub__title { font-size: 1.08rem; line-height: 1.4; margin: 0 0 .45rem; letter-spacing: -0.01em; }
.pub__authors { margin: 0 0 .2rem; color: var(--ink-soft); font-size: .95rem; }
.pub__authors strong { color: var(--ink); font-weight: 600; }
.pub__note { color: var(--ink-faint); font-weight: 400; font-size: .85em; }
.pub__venue { margin: 0; color: var(--ink-faint); font-size: .92rem; font-style: italic; }
.pub__tag {
  font-style: normal; display: inline-block; margin-left: .4rem;
  font-size: .72rem; letter-spacing: .04em; text-transform: uppercase;
  color: var(--accent); background: var(--accent-soft);
  padding: .1rem .5rem; border-radius: 999px; vertical-align: middle;
}
.pub__abstract { margin: .7rem 0 0; }
.pub__abstract summary {
  cursor: pointer; color: var(--accent); font-size: .9rem; font-weight: 500;
  list-style: none; width: max-content;
}
.pub__abstract summary::-webkit-details-marker { display: none; }
.pub__abstract summary::before { content: "+ "; }
.pub__abstract[open] summary::before { content: "– "; }
.pub__abstract p {
  margin: .7rem 0 0; color: var(--ink-soft); font-size: .92rem; line-height: 1.65;
  max-width: 70ch;
}
.pub__links { margin: .6rem 0 0; }
.pub__links a {
  text-decoration: none; color: var(--ink-soft); font-size: .88rem; font-weight: 500;
  border-bottom: 1px solid var(--line); transition: color .2s, border-color .2s;
}
.pub__links a:hover { color: var(--accent); border-color: var(--accent); }

.media { list-style: none; margin: 0; padding: 0; }
.media li {
  padding: .7rem 0; border-top: 1px solid var(--line);
  color: var(--ink-soft); font-size: .94rem;
  display: flex; flex-wrap: wrap; gap: .5rem; align-items: baseline;
}
.media__src {
  font-family: var(--font-mono);
  font-size: .7rem; letter-spacing: .05em; text-transform: uppercase;
  color: var(--accent); font-weight: 500; min-width: 7ch;
}
.media a {
  text-decoration: none; color: var(--ink-soft);
  border-bottom: 1px solid var(--line); transition: color .2s, border-color .2s;
}
.media a:hover { color: var(--accent); border-color: var(--accent); }
.media__date { margin-left: auto; color: var(--ink-faint); font-variant-numeric: tabular-nums; font-size: .85rem; }

/* ---------- Curriculum ---------- */
.cv-group {
  font-family: var(--font-mono);
  font-size: .76rem; text-transform: uppercase; letter-spacing: .1em;
  color: var(--ink-faint); font-weight: 500; margin: 2.2rem 0 1.1rem;
}
.timeline { list-style: none; margin: 0; padding: 0; }
.timeline__item {
  display: grid; grid-template-columns: 130px 1fr; gap: 1rem;
  padding: 1.1rem 0; border-top: 1px solid var(--line);
}
.timeline__item:first-child { border-top: none; }
.timeline__date { color: var(--ink-faint); font-size: .9rem; font-variant-numeric: tabular-nums; padding-top: .15rem; }
.timeline__body h4 { margin: 0 0 .3rem; font-size: 1.02rem; letter-spacing: -0.01em; }
.timeline__body h4 em { color: var(--ink-faint); font-weight: 400; font-size: .85em; }
.timeline__body p { margin: 0; color: var(--ink-soft); font-size: .93rem; }

.cv-grid { display: grid; gap: 1.5rem; grid-template-columns: 1fr; margin-top: .5rem; }
@media (min-width: 720px) { .cv-grid { grid-template-columns: 1fr 1fr; gap: 2.5rem; } }
.cv-list { margin: 0; padding-left: 1.1rem; }
.cv-list li { color: var(--ink-soft); font-size: .93rem; margin-bottom: .7rem; }
.cv-list strong { color: var(--ink); }

/* ---------- Contact ---------- */
.section--contact { }
.contact__lede { font-size: 1.15rem; color: var(--ink-soft); max-width: 50ch; margin: 0 0 1.8rem; }
.contact__actions { margin: 0 0 1.6rem; }
.contact__inline { list-style: none; margin: 0; padding: 0; display: flex; flex-wrap: wrap; gap: 1.4rem; }
.contact__inline a {
  text-decoration: none; color: var(--ink-soft); font-weight: 500; font-size: .98rem;
  padding-bottom: 2px; border-bottom: 1px solid var(--line);
  transition: color .2s ease, border-color .2s ease;
}
.contact__inline a:hover { color: var(--accent); border-color: var(--accent); }

/* ---------- Footer ---------- */
.site-footer {
  max-width: var(--maxw); margin: 0 auto;
  padding: 2.5rem var(--gutter) 3.5rem;
  border-top: 1px solid var(--line);
  display: flex; flex-wrap: wrap; justify-content: space-between; gap: .5rem;
  color: var(--ink-faint); font-size: .88rem;
}
.site-footer p { margin: 0; }

/* ---------- Mobile nav ---------- */
@media (max-width: 680px) {
  .nav__toggle {
    display: inline-flex; flex-direction: column; justify-content: center; gap: 5px;
    width: 40px; height: 40px; background: none; border: none; cursor: pointer; padding: 8px;
  }
  .nav__toggle span {
    display: block; height: 2px; width: 100%; background: var(--ink); border-radius: 2px;
    transition: transform .25s ease, opacity .2s ease;
  }
  .nav__toggle[aria-expanded="true"] span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
  .nav__toggle[aria-expanded="true"] span:nth-child(2) { opacity: 0; }
  .nav__toggle[aria-expanded="true"] span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

  .nav__menu {
    position: fixed; inset: 57px 0 auto 0;
    flex-direction: column; align-items: flex-start; gap: 0;
    background: var(--bg); border-bottom: 1px solid var(--line);
    padding: .5rem var(--gutter) 1.2rem;
    transform: translateY(-120%); transition: transform .3s ease;
    box-shadow: 0 12px 30px rgba(0,0,0,.08);
  }
  .nav__menu.is-open { transform: translateY(0); }
  .nav__menu li { width: 100%; }
  .nav__menu li a { display: block; padding: .85rem 0; width: 100%; border-bottom: 1px solid var(--line); }
  .nav__menu li:last-child { padding-top: .9rem; }
  .pub { grid-template-columns: 1fr; gap: .35rem; }
  .pub__year { padding-top: 0; }
  .timeline__item { grid-template-columns: 1fr; gap: .25rem; }
}