/* AI Trends — editorial / Swiss data-viz. Disciplined palette, strong type scale,
   semantic colour (warm = emerging/hot, cool = fading). No framework. */

:root {
  --paper: #f6f4ee;
  --paper-2: #efece3;
  --card: #fffdf8;
  --ink: #17150f;
  --muted: #6c6757;
  --line: rgba(23, 21, 15, 0.14);
  --line-soft: rgba(23, 21, 15, 0.08);

  --accent: #d9461b;        /* emerging / hot */
  --accent-ink: #8f2c0f;
  --cool: #2c5aa6;          /* fading / cool */
  --cool-ink: #1d3c70;
  --top: #1c1a14;           /* top / established */

  --text-hero: clamp(2.2rem, 1.3rem + 3vw, 4rem);
  --text-h2: clamp(1.6rem, 1.1rem + 1.8vw, 2.6rem);
  --space-section: clamp(3.5rem, 2.5rem + 4vw, 7rem);

  --sans: "Inter", system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  --mono: ui-monospace, "SF Mono", "JetBrains Mono", "Cascadia Code", Menlo, monospace;

  --dur: 240ms;
  --ease: cubic-bezier(0.16, 1, 0.3, 1);
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  * { animation-duration: 0.001ms !important; transition-duration: 0.001ms !important; }
}

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--sans);
  font-size: clamp(1rem, 0.96rem + 0.2vw, 1.08rem);
  line-height: 1.55;
  -webkit-font-smoothing: antialiased;
}

.wrap { width: min(1240px, 92vw); margin-inline: auto; }

a { color: inherit; }
em { font-style: italic; }

:focus-visible {
  outline: 2.5px solid var(--accent);
  outline-offset: 3px;
  border-radius: 2px;
}

/* ---------- header ---------- */
.site-head {
  position: sticky; top: 0; z-index: 20;
  background: color-mix(in oklab, var(--paper) 86%, transparent);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--line-soft);
}
.site-head__inner { display: flex; align-items: center; justify-content: space-between; height: 64px; }
.brand { display: inline-flex; align-items: center; gap: 0.6ch; text-decoration: none; font-weight: 800; letter-spacing: -0.02em; }
.brand__logo { width: 1.9em; height: 1.9em; display: block; }
.brand__dim { color: var(--muted); font-weight: 600; }
.nav { display: flex; gap: clamp(1rem, 3vw, 2rem); align-items: center; font-weight: 600; }
.nav a { text-decoration: none; color: var(--muted); transition: color var(--dur) var(--ease); }
.nav a:hover { color: var(--ink); }
.nav__ext { color: var(--ink); }

/* Hamburger toggle — hidden on desktop, revealed on narrow screens. */
.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 42px; height: 42px;
  padding: 0;
  background: transparent;
  border: 1px solid var(--line);
  border-radius: 10px;
  cursor: pointer;
}
.nav-toggle__bar {
  display: block; width: 20px; height: 2px; margin: 0 auto;
  background: var(--ink);
  transition: transform var(--dur) var(--ease), opacity var(--dur) var(--ease);
}

/* Narrow screens: brand + menu button on the bar; nav collapses into a
   tappable dropdown list that the button opens/closes. */
@media (max-width: 640px) {
  .site-head__inner { flex-wrap: wrap; min-height: 64px; height: auto; }
  .nav-toggle { display: flex; }
  .nav {
    flex-basis: 100%;
    display: none;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    padding-bottom: 0.4rem;
  }
  .site-head__inner.is-open .nav { display: flex; }
  .nav a { padding: 0.75rem 0.2rem; border-top: 1px solid var(--line-soft); }
  /* morph the bars into an X while open */
  .site-head__inner.is-open .nav-toggle__bar:nth-child(1) { transform: translateY(7px) rotate(45deg); }
  .site-head__inner.is-open .nav-toggle__bar:nth-child(2) { opacity: 0; }
  .site-head__inner.is-open .nav-toggle__bar:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }
}

/* ---------- hero ---------- */
.hero { padding: clamp(2.2rem, 1.4rem + 2.5vw, 4rem) 0; border-bottom: 1px solid var(--line); }
.hero__inner { display: grid; grid-template-columns: 1.5fr 1fr; gap: clamp(2rem, 4vw, 4.5rem); align-items: center; }
@media (max-width: 820px) { .hero__inner { grid-template-columns: 1fr; gap: 1.8rem; } }
.eyebrow { font-family: var(--mono); font-size: 0.8rem; letter-spacing: 0.04em; color: var(--muted); text-transform: uppercase; margin: 0 0 1rem; }
.hero__title { font-size: var(--text-hero); line-height: 1.02; letter-spacing: -0.03em; font-weight: 800; margin: 0 0 1rem; }
.hero__title em { color: var(--accent); margin-right: 0.22em; }
.hero__title .hero__hl { color: var(--cool); }
.hero__lede { font-size: clamp(1rem, 0.95rem + 0.35vw, 1.2rem); max-width: 52ch; color: #2c291f; margin: 0; line-height: 1.5; }
.hero__lede strong { color: var(--ink); }
.hero__panel { background: var(--card); border: 1px solid var(--line); border-radius: 16px; padding: clamp(1.3rem, 2.5vw, 2rem); }
.hero__stats { display: grid; grid-template-columns: 1fr 1fr; gap: 1.3rem 1.4rem; }
.stat { display: flex; flex-direction: column; }
.stat__num { font-family: var(--mono); font-size: clamp(1.5rem, 1rem + 1.4vw, 2.2rem); font-weight: 700; line-height: 1; letter-spacing: -0.03em; }
.stat__label { font-size: 0.75rem; color: var(--muted); text-transform: uppercase; letter-spacing: 0.05em; margin-top: 0.45rem; }

/* ---------- sections ---------- */
.section { padding: clamp(2rem, 1.4rem + 2vw, 3.5rem) 0; }
.section--alt { background: var(--paper-2); border-top: 1px solid var(--line); }
.section__head { margin-bottom: clamp(1.6rem, 3vw, 2.8rem); }
.section__title { font-size: var(--text-h2); letter-spacing: -0.03em; font-weight: 800; margin: 0 0 0.4rem; display: flex; align-items: baseline; gap: 0.7ch; }
.section__num { font-family: var(--mono); font-size: 0.5em; color: var(--accent); font-weight: 700; }
.section__hint { color: var(--muted); margin: 0; max-width: 60ch; line-height: 1.5; text-wrap: pretty; }

/* ---------- picker (pills) ---------- */
.picker { display: flex; flex-direction: column; gap: 0.7rem; margin-bottom: 2.2rem; }
.picker__row { display: flex; flex-wrap: wrap; gap: 0.5rem; }
.pill {
  font: inherit; font-weight: 700; cursor: pointer;
  border: 1px solid var(--line); background: transparent; color: var(--ink);
  padding: 0.45rem 1rem; border-radius: 999px;
  transition: background var(--dur) var(--ease), color var(--dur) var(--ease), border-color var(--dur) var(--ease), transform var(--dur) var(--ease);
}
.picker__row--years .pill { font-family: var(--mono); font-weight: 600; }
.pill:hover { border-color: var(--ink); transform: translateY(-1px); }
.pill[aria-pressed="true"] { background: var(--ink); color: var(--paper); border-color: var(--ink); }
.pill:disabled { opacity: 0.32; cursor: not-allowed; transform: none; }

/* ---------- trend panel ---------- */
.trend-panel { display: grid; grid-template-columns: 1.1fr 1fr; gap: clamp(1.2rem, 3vw, 2.4rem); align-items: start; }
@media (max-width: 860px) { .trend-panel { grid-template-columns: 1fr; } }

.cols { display: grid; grid-template-columns: repeat(3, 1fr); gap: 1rem; }
@media (max-width: 560px) { .cols { grid-template-columns: 1fr; } }
.col__h { font-family: var(--mono); font-size: 0.78rem; text-transform: uppercase; letter-spacing: 0.05em; margin: 0 0 0.8rem; padding-bottom: 0.5rem; border-bottom: 2px solid currentColor; display: inline-block; }
.col--top .col__h { color: var(--top); }
.col--emerging .col__h { color: var(--accent); }
.col--fading .col__h { color: var(--cool); }
.rank { list-style: none; margin: 0; padding: 0; display: flex; flex-direction: column; gap: 0.45rem; counter-reset: r; }
.rank li { counter-increment: r; }
.chip {
  display: flex; align-items: baseline; gap: 0.6ch; width: 100%; text-align: left;
  font: inherit; cursor: pointer; background: var(--card); color: var(--ink);
  border: 1px solid var(--line-soft); border-radius: 10px; padding: 0.55rem 0.7rem;
  transition: border-color var(--dur) var(--ease), transform var(--dur) var(--ease), box-shadow var(--dur) var(--ease);
}
.chip:hover { transform: translateY(-2px); border-color: var(--line); box-shadow: 0 8px 22px -16px rgba(0,0,0,0.5); }
.chip__rank { font-family: var(--mono); font-size: 0.78rem; color: var(--muted); }
.chip__rank::before { content: counter(r) ". "; }
.chip__name { font-weight: 650; }
.col--emerging .chip:hover { border-color: var(--accent); }
.col--fading .chip:hover { border-color: var(--cool); }

/* bar chart */
.chart { background: var(--card); border: 1px solid var(--line-soft); border-radius: 14px; padding: clamp(1rem, 2vw, 1.5rem); }
.chart__h { font-family: var(--mono); font-size: 0.78rem; text-transform: uppercase; letter-spacing: 0.05em; color: var(--muted); margin: 0 0 1rem; }
.bar { display: grid; grid-template-columns: 8.5rem 1fr auto; align-items: center; gap: 0.7rem; padding: 0.28rem 0; cursor: pointer; width: 100%; border: 0; background: none; font: inherit; color: inherit; text-align: left; }
.bar__name { font-size: 0.86rem; font-weight: 600; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.bar__track { height: 12px; background: var(--paper-2); border-radius: 999px; overflow: hidden; }
.bar__fill { height: 100%; background: linear-gradient(90deg, var(--cool), var(--accent)); border-radius: 999px; transform-origin: left; animation: grow var(--dur) var(--ease); }
@keyframes grow { from { transform: scaleX(0.02); } }
.bar__val { font-family: var(--mono); font-size: 0.8rem; color: var(--muted); }
.bar:hover .bar__name { color: var(--accent); }

.empty { color: var(--muted); font-style: italic; padding: 1rem 0; }

/* ---------- filters ---------- */
.filters { display: grid; grid-template-columns: repeat(3, minmax(0,1fr)) 1.4fr; gap: 1rem; margin-bottom: 1.6rem; }
@media (max-width: 760px) { .filters { grid-template-columns: 1fr 1fr; } .field--grow { grid-column: 1 / -1; } }
.field { display: flex; flex-direction: column; gap: 0.4rem; }
.field__label { font-family: var(--mono); font-size: 0.72rem; text-transform: uppercase; letter-spacing: 0.05em; color: var(--muted); }
.field__input { font: inherit; padding: 0.6rem 0.75rem; border: 1px solid var(--line); border-radius: 10px; background: var(--card); color: var(--ink); transition: border-color var(--dur) var(--ease); }
.field__input:hover { border-color: var(--ink); }

.result-meta { font-family: var(--mono); font-size: 0.85rem; color: var(--muted); margin: 0 0 1.2rem; }

/* ---------- paper cards ---------- */
.papers { list-style: none; margin: 0; padding: 0; display: grid; gap: 0.6rem; align-items: start; grid-template-columns: repeat(auto-fill, minmax(min(100%, 32rem), 1fr)); }
.paper { background: var(--card); border: 1px solid var(--line-soft); border-radius: 10px; padding: 0.7rem 0.85rem; transition: border-color var(--dur) var(--ease), box-shadow var(--dur) var(--ease); }
.paper:hover { border-color: var(--line); box-shadow: 0 12px 30px -22px rgba(0,0,0,0.55); }
.paper__top { display: flex; gap: 1rem; justify-content: space-between; align-items: baseline; }
.paper__title { font-size: 0.98rem; font-weight: 700; letter-spacing: -0.01em; margin: 0; line-height: 1.25; }
.paper__title a { text-decoration: none; background-image: linear-gradient(var(--accent), var(--accent)); background-size: 0% 2px; background-repeat: no-repeat; background-position: 0 100%; transition: background-size var(--dur) var(--ease); }
.paper__title a:hover { background-size: 100% 2px; }
.paper__venue { font-family: var(--mono); font-size: 0.76rem; color: var(--muted); white-space: nowrap; }
.paper__authors { color: var(--muted); font-size: 0.8rem; margin: 0.25rem 0 0.4rem; }
.paper__abstract { font-size: 0.84rem; line-height: 1.45; color: #343026; margin: 0 0 0.55rem; display: -webkit-box; -webkit-line-clamp: 3; line-clamp: 3; -webkit-box-orient: vertical; overflow: hidden; }
.tags { display: flex; flex-wrap: wrap; gap: 0.4rem; }
.tag { font-family: var(--mono); font-size: 0.72rem; padding: 0.2rem 0.55rem; border-radius: 999px; background: var(--paper-2); border: 1px solid var(--line-soft); cursor: pointer; transition: background var(--dur) var(--ease), color var(--dur) var(--ease); }
.tag:hover { background: var(--ink); color: var(--paper); }
.paper__links { margin-left: auto; display: inline-flex; gap: 0.7rem; align-items: center; }
.paper__link { font-family: var(--mono); font-size: 0.72rem; font-weight: 600; color: var(--cool-ink); text-decoration: none; white-space: nowrap; }
.paper__link:hover { color: var(--accent); text-decoration: underline; }

.more { text-align: center; margin-top: 1.6rem; }
.btn { font: inherit; font-weight: 700; cursor: pointer; padding: 0.7rem 1.6rem; border-radius: 999px; border: 1px solid var(--ink); background: transparent; color: var(--ink); transition: background var(--dur) var(--ease), color var(--dur) var(--ease); }
.btn:hover { background: var(--ink); color: var(--paper); }

.loading { color: var(--muted); font-family: var(--mono); font-size: 0.85rem; padding: 2rem 0; }

/* ---------- footer ---------- */
.site-foot { border-top: 1px solid var(--line); padding: 2.5rem 0; }
.site-foot__inner { display: flex; flex-wrap: wrap; gap: 1rem; justify-content: space-between; color: var(--muted); font-size: 0.9rem; }
.site-foot__inner p { margin: 0; max-width: 62ch; }
.site-foot a { color: var(--ink); }

/* ---------- side navigation (quick jump) ---------- */
.sidenav { position: fixed; right: clamp(0.8rem, 2vw, 2rem); top: 50%; transform: translateY(-50%); z-index: 30; display: flex; flex-direction: column; gap: 0.9rem; }
.sidenav a { display: flex; align-items: center; gap: 0.6rem; text-decoration: none; color: var(--muted); flex-direction: row-reverse; }
.sidenav__dot { width: 9px; height: 9px; border-radius: 50%; border: 1.5px solid var(--muted); background: transparent; transition: background var(--dur) var(--ease), border-color var(--dur) var(--ease), transform var(--dur) var(--ease); flex: none; }
.sidenav__label { font-size: 0.78rem; font-weight: 600; opacity: 0; transform: translateX(6px); transition: opacity var(--dur) var(--ease), transform var(--dur) var(--ease); white-space: nowrap; }
.sidenav a:hover .sidenav__label, .sidenav a:focus-visible .sidenav__label { opacity: 1; transform: translateX(0); }
.sidenav a:hover .sidenav__dot { border-color: var(--ink); }
.sidenav a.active .sidenav__dot { background: var(--accent); border-color: var(--accent); transform: scale(1.25); }
.sidenav a.active .sidenav__label { opacity: 1; transform: translateX(0); color: var(--ink); }
@media (max-width: 1100px) { .sidenav { display: none; } }