/* ===========================================================================
   NG5004 — AI-driven Innovation from Deep-tech Research
   Palette anchored on official NUS Blue (#003D7C) and NUS Orange (#EF7C00).
   =========================================================================== */

:root {
  /* Core palette */
  --navy-950: #041427;   /* hero background, deepest */
  --navy-900: #06213f;
  --nus-blue: #003d7c;   /* official NUS Blue */
  --blue-600: #1f5aa5;
  --nus-orange: #ef7c00; /* official NUS Orange */
  --orange-400: #ff9a33;

  /* Neutrals */
  --paper: #f7f6f2;      /* warm off-white reading surface */
  --paper-tint: #eef1f6; /* cool section fill */
  --ink: #17233a;        /* body text */
  --slate: #5b6b82;      /* muted text */
  --line: #dfe3ea;       /* hairlines */
  --white: #ffffff;

  /* Type */
  --display: "Space Grotesk", system-ui, sans-serif;
  --body: "Inter", system-ui, sans-serif;
  --mono: "JetBrains Mono", ui-monospace, monospace;

  /* Layout */
  --maxw: 1120px;
  --gutter: clamp(1.25rem, 4vw, 3.5rem);
  --radius: 14px;
}

* { box-sizing: border-box; margin: 0; padding: 0; }

html { scroll-behavior: smooth; }

body {
  font-family: var(--body);
  color: var(--ink);
  background: var(--paper);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

h1, h2, h3 { font-family: var(--display); line-height: 1.08; font-weight: 600; letter-spacing: -0.02em; }

a { color: inherit; text-decoration: none; }

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

:focus-visible { outline: 3px solid var(--nus-orange); outline-offset: 3px; border-radius: 4px; }

/* ---------- Shared bits ---------- */
.eyebrow {
  font-family: var(--mono);
  font-size: .74rem;
  letter-spacing: .18em;
  text-transform: uppercase;
  color: var(--nus-orange);
  margin-bottom: 1.1rem;
}
.eyebrow--onDark { color: var(--orange-400); }

.section { max-width: var(--maxw); margin: 0 auto; padding: clamp(4.5rem, 9vw, 8rem) var(--gutter); }
/* offset anchored jumps so titles clear the sticky nav */
#about, #people, #pathway, #materials { scroll-margin-top: 72px; }
.section__head { max-width: 46rem; margin-bottom: clamp(2.5rem, 5vw, 4rem); }
.section__title { font-size: clamp(1.9rem, 4.4vw, 3.05rem); }
.section__sub { margin-top: 1.25rem; color: var(--slate); font-size: 1.08rem; max-width: 40rem; }

.btn {
  display: inline-flex; align-items: center; justify-content: center;
  font-family: var(--display); font-weight: 500; font-size: .98rem;
  padding: .85rem 1.5rem; border-radius: 999px;
  transition: transform .18s ease, background .18s ease, box-shadow .18s ease, color .18s ease;
}
.btn--primary { background: var(--nus-orange); color: #fff; box-shadow: 0 8px 24px -8px rgba(239,124,0,.6); }
.btn--primary:hover { transform: translateY(-2px); background: var(--orange-400); }
.btn--ghost { color: #fff; border: 1px solid rgba(255,255,255,.3); }
.btn--ghost:hover { border-color: #fff; background: rgba(255,255,255,.08); }

/* ---------- Nav ---------- */
.nav {
  position: sticky; top: 0; z-index: 50;
  display: flex; align-items: center; justify-content: space-between;
  padding: .9rem var(--gutter);
  background: rgba(4, 20, 39, .82);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid rgba(255,255,255,.08);
}
.nav__brand { display: flex; align-items: baseline; gap: .55rem; color: #fff; font-family: var(--display); }
.nav__code { font-weight: 700; letter-spacing: .02em; }
.nav__sep { color: var(--orange-400); }
.nav__short { color: rgba(255,255,255,.7); font-size: .95rem; }
.nav__links { display: flex; gap: 1.6rem; }
.nav__links a { color: rgba(255,255,255,.78); font-size: .92rem; font-weight: 500; transition: color .16s ease; }
.nav__links a:hover { color: var(--orange-400); }

/* ---------- Hero ---------- */
.hero {
  position: relative; overflow: hidden;
  background:
    radial-gradient(1200px 600px at 78% -10%, rgba(31,90,165,.55), transparent 60%),
    radial-gradient(900px 500px at 10% 110%, rgba(239,124,0,.16), transparent 55%),
    linear-gradient(180deg, var(--navy-900), var(--navy-950));
  color: #fff;
}
.hero__canvas { position: absolute; inset: 0; width: 100%; height: 100%; }
.hero__inner {
  position: relative; z-index: 2;
  max-width: var(--maxw); margin: 0 auto;
  padding: clamp(4rem, 10vw, 8rem) var(--gutter) clamp(6rem, 11vw, 9rem);
}
.hero__title {
  font-size: clamp(2.6rem, 7vw, 5.1rem);
  font-weight: 700; letter-spacing: -0.03em; margin-bottom: 1.6rem;
}
.hero__title-accent {
  background: linear-gradient(100deg, var(--orange-400), var(--nus-orange));
  -webkit-background-clip: text; background-clip: text; color: transparent;
}
.hero__lede { max-width: 38rem; font-size: clamp(1.05rem, 1.6vw, 1.22rem); color: rgba(255,255,255,.82); }
.hero__info {
  display: flex; flex-wrap: wrap; gap: 1.3rem 2.6rem; margin: 2.4rem 0;
  padding: 1.25rem 1.6rem; border-radius: 14px;
  background: rgba(255, 255, 255, .05);
  border: 1px solid rgba(255, 255, 255, .14);
  border-left: 3px solid var(--nus-orange);
  backdrop-filter: blur(2px);
}
.hero__infoItem { display: flex; align-items: center; gap: .85rem; }
.hero__infoIcon { width: 24px; height: 24px; color: var(--orange-400); flex-shrink: 0; }
.hero__infoKey {
  display: block; font-family: var(--mono); font-size: .64rem; letter-spacing: .18em;
  text-transform: uppercase; color: rgba(255, 255, 255, .55); margin-bottom: .15rem;
}
.hero__infoVal { display: block; font-family: var(--display); font-size: 1.2rem; font-weight: 600; color: #fff; }
.hero__cta { display: flex; flex-wrap: wrap; gap: 1rem; }
.hero__scroll {
  position: absolute; bottom: 1.6rem; left: 50%; transform: translateX(-50%); z-index: 2;
  width: 26px; height: 42px; border: 2px solid rgba(255,255,255,.35); border-radius: 999px;
  display: grid; place-items: start center; padding-top: 7px;
}
.hero__scroll span { width: 4px; height: 8px; border-radius: 4px; background: var(--orange-400); animation: scrolldot 1.6s ease-in-out infinite; }
@keyframes scrolldot { 0%,100% { opacity: 0; transform: translateY(0); } 50% { opacity: 1; transform: translateY(9px); } }

/* ---------- About ---------- */
.about__lead { max-width: 46rem; }
.about__lead p { font-size: 1.18rem; color: #2a374d; margin-bottom: 1.3rem; }
.about__lead p:last-child { margin-bottom: 0; }

/* ---------- People ---------- */
.people { background: var(--paper-tint); max-width: none; }
.people > .section__head, .people__grid { max-width: var(--maxw); margin-left: auto; margin-right: auto; }
.people__grid { display: grid; grid-template-columns: 1fr 1fr; gap: 1.5rem; }
.person {
  background: var(--white); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 2.2rem; position: relative; overflow: hidden;
  display: flex; gap: 1.6rem; align-items: center;
}
.person::before { content: ""; position: absolute; left: 0; top: 0; bottom: 0; width: 4px; background: var(--nus-orange); }
.person__photo {
  flex-shrink: 0; width: 104px; height: 104px; border-radius: 14px; object-fit: cover;
  object-position: center top; background: var(--paper-tint);
  border: 1px solid var(--line);
}
.person__text { min-width: 0; }
.person__role {
  display: inline-block; font-family: var(--mono); font-size: .82rem; font-weight: 500;
  letter-spacing: .1em; text-transform: uppercase; color: var(--nus-orange);
  background: rgba(239, 124, 0, .1); border: 1px solid rgba(239, 124, 0, .28);
  padding: .34rem .8rem; border-radius: 999px; margin-bottom: .85rem;
}
.person__name { font-size: clamp(1.3rem, 1.7vw, 1.6rem); margin-bottom: .6rem; color: var(--nus-blue); white-space: nowrap; }
.person__link {
  display: inline-flex; align-items: center; gap: .35rem;
  font-family: var(--mono); font-size: .82rem; font-weight: 500; color: var(--nus-orange);
  border-bottom: 1px solid transparent; transition: border-color .16s ease;
}
.person__link:hover { border-color: var(--nus-orange); }

/* ---------- Pathway / timeline ---------- */
.timeline { list-style: none; position: relative; max-width: 46rem; margin-left: clamp(0.5rem, 3vw, 2rem); }
.timeline::before {
  content: ""; position: absolute; left: 15px; top: 8px; bottom: 8px; width: 2px;
  background: linear-gradient(180deg, var(--nus-blue) 0%, var(--blue-600) 45%, var(--nus-orange) 100%);
}
.week {
  position: relative; display: flex; gap: 1.3rem; align-items: flex-start;
  padding: 1.1rem 0 1.1rem 3.2rem;
}
.week::before {
  content: ""; position: absolute; left: 9px; top: 1.55rem; width: 14px; height: 14px;
  border-radius: 50%; background: var(--white); border: 3px solid var(--nus-blue);
  box-shadow: 0 0 0 4px var(--paper);
  transition: transform .2s ease, border-color .2s ease;
}
.week:hover::before { transform: scale(1.18); }
.week__no {
  flex-shrink: 0; font-family: var(--mono); font-weight: 500; font-size: .95rem;
  color: var(--nus-blue); min-width: 2.2rem; padding-top: .15rem;
}
.week__date {
  display: block; font-family: var(--mono); font-size: .74rem; letter-spacing: .06em;
  color: var(--nus-orange); margin-bottom: .25rem;
}
.week__body h3 { font-size: 1.2rem; }

/* progressively warmer nodes down the timeline */
.week:nth-of-type(n+9)::before { border-color: var(--blue-600); }
.week:nth-of-type(n+14)::before { border-color: var(--nus-orange); }
.week:nth-of-type(n+14) .week__no { color: var(--nus-orange); }

.week--break { opacity: .72; }
.week--break::before { background: var(--paper-tint); border-color: var(--line); border-style: dashed; }
.week--break .week__no { color: var(--slate); }
.week--break .week__date { color: var(--slate); }
.week--break .week__body h3 { font-weight: 500; color: var(--slate); }

/* ---------- Materials ---------- */
.materials { background: var(--navy-950); color: #fff; max-width: none; }
.materials > .section__head, .materials__block { max-width: var(--maxw); margin-left: auto; margin-right: auto; }
.materials .section__title { color: #fff; }
.materials .section__sub { color: rgba(255,255,255,.7); }

.materials__block { margin-top: 2.8rem; }
.materials__blockTitle {
  font-family: var(--mono); font-size: .8rem; font-weight: 500; letter-spacing: .14em;
  text-transform: uppercase; color: var(--orange-400);
  padding-bottom: .8rem; margin-bottom: .4rem; border-bottom: 1px solid rgba(255,255,255,.14);
}
.materials__empty { color: rgba(255,255,255,.55); font-size: .96rem; padding: 1rem 0; }

/* slide download rows */
.slides { list-style: none; max-width: 34rem; }
.slide {
  display: flex; align-items: center; justify-content: space-between; gap: 1.2rem;
  padding: 1rem .4rem; border-bottom: 1px solid rgba(255,255,255,.09);
}
.slide__wk {
  font-family: var(--mono); font-weight: 500; font-size: 1.02rem;
  color: rgba(255,255,255,.92);
}
.slide__dl {
  flex-shrink: 0; display: inline-flex; align-items: center; gap: .5rem;
  font-family: var(--display); font-weight: 500; font-size: .9rem; color: #fff;
  background: var(--nus-orange); padding: .5rem .95rem; border-radius: 999px;
  transition: background .18s ease, transform .18s ease;
}
.slide__dl:hover { background: var(--orange-400); transform: translateY(-1px); }
.slide__ext { font-family: var(--mono); font-size: .72rem; opacity: .85; }
.slides__empty { color: rgba(255,255,255,.55); font-size: .96rem; padding: 1rem 0; }

/* ---------- Footer ---------- */
.footer { background: var(--nus-blue); color: #fff; }
.footer__inner {
  max-width: var(--maxw); margin: 0 auto; padding: 2.6rem var(--gutter);
  display: flex; justify-content: space-between; align-items: center; gap: 1.5rem; flex-wrap: wrap;
}
.footer__code { font-family: var(--display); font-weight: 700; font-size: 1.1rem; }
.footer__name { color: rgba(255,255,255,.75); font-size: .95rem; }
.footer__org { font-family: var(--mono); font-size: .8rem; letter-spacing: .06em; color: rgba(255,255,255,.7); }

/* ---------- Reveal on scroll ---------- */
.reveal { opacity: 0; transform: translateY(18px); transition: opacity .6s ease, transform .6s ease; }
.reveal.is-in { opacity: 1; transform: none; }

/* ---------- Responsive ---------- */
@media (max-width: 860px) {
  .nav__links { display: none; }
  .people__grid { grid-template-columns: 1fr; }
}
/* let long names wrap instead of clipping on very narrow screens */
@media (max-width: 560px) {
  .person__name { white-space: normal; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .hero__scroll span { animation: none; }
  .reveal { opacity: 1; transform: none; transition: none; }
}