/* ============================================================
   2-Sigma — Design System
   Content/structure: "Tools for Precision Education" wireframe
   Look & feel: 2-Sigma Figma branding (violet → magenta → pink
   gradient accent, airy light theme, soft lavender washes).
   ============================================================ */

/* ---------- Design tokens ---------- */
:root {
  /* Brand — real 2-Sigma palette (deep purple #5A1F73 → pink #F2529D) */
  --violet-700: #5a1f73;
  --violet-600: #6e2487;
  --violet-500: #8b2e84;
  --magenta-500: #f2529d;
  --pink-600: #f2529d;
  --pink-500: #f573ae;

  /* Ink / neutrals */
  --ink-900: #1b2244;
  --ink-800: #232b4d;
  --ink-700: #2f3860;
  --slate-600: #515a78;
  --slate-500: #6b7280;
  --slate-400: #98a0b3;
  --slate-300: #c3c9d6;

  /* Surfaces */
  --bg: #ffffff;
  --bg-soft: #f6f7fc;
  --bg-tint: #faf8ff;
  --border: #e9eaf2;
  --border-strong: #dfe1ee;

  /* Effects */
  --gradient-brand: linear-gradient(95deg, #5a1f73 0%, #a03587 48%, #f2529d 100%);
  --gradient-brand-soft: linear-gradient(120deg, #efe2f1 0%, #fce4ef 100%);
  --shadow-sm: 0 1px 2px rgba(27, 34, 68, 0.06);
  --shadow-md: 0 10px 30px rgba(90, 31, 115, 0.1);
  --shadow-lg: 0 30px 70px rgba(90, 31, 115, 0.18);

  /* Typography */
  --font-display: "Poppins", "Segoe UI", system-ui, sans-serif;
  --font-body: "Inter", "Segoe UI", system-ui, sans-serif;

  /* Layout */
  --maxw: 1640px;
  --radius-sm: 10px;
  --radius: 16px;
  --radius-lg: 22px;
  --radius-pill: 999px;
}

/* ---------- Reset ---------- */
*,
*::before,
*::after { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: var(--font-body);
  color: var(--slate-600);
  background: var(--bg);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

img { max-width: 100%; display: block; }
a { color: inherit; text-decoration: none; }
ul { margin: 0; padding: 0; list-style: none; }

h1, h2, h3, h4 {
  font-family: var(--font-display);
  color: var(--ink-900);
  margin: 0;
  line-height: 1.12;
  letter-spacing: -0.01em;
}

/* ---------- Helpers ---------- */
.container {
  width: 100%;
  max-width: var(--maxw);
  margin-inline: auto;
  padding-inline: 24px;
}
.container--narrow { max-width: 1240px; }

.section { padding-block: 96px; }
.section--soft { background: var(--bg-soft); }

/* Campus photo backdrop with brand-tinted scrim for readability */
.section--campus {
  position: relative;
  isolation: isolate;
  background-image:
    linear-gradient(180deg, rgba(0, 0, 0, 0.42) 0%, rgba(0, 0, 0, 0.42) 100%),
    url("../assets/campus.jpg");
  background-size: cover;
  background-position: center 38%;
}
.section--campus .section-head h2 { color: #fff; }
.section--campus .section-head .eyebrow {
  background: none;
  -webkit-text-fill-color: initial;
  color: #fff;
}

.eyebrow {
  font-family: var(--font-body);
  font-weight: 700;
  font-size: 0.78rem;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  background: var(--gradient-brand);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  margin: 0 0 14px;
}

.gradient-text {
  background: var(--gradient-brand);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.section-head {
  text-align: center;
  max-width: 640px;
  margin-inline: auto;
  margin-bottom: 56px;
}
.section-head h2 { font-size: clamp(2rem, 3.4vw, 2.6rem); font-weight: 700; }
.section-head p { margin: 16px 0 0; font-size: 1.05rem; color: var(--slate-500); }

/* ---------- Buttons ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  font-family: var(--font-body);
  font-weight: 600;
  font-size: 0.95rem;
  padding: 13px 26px;
  border-radius: var(--radius-pill);
  border: 1.5px solid transparent;
  cursor: pointer;
  transition: transform 0.18s ease, box-shadow 0.18s ease, background 0.18s ease, color 0.18s ease;
  white-space: nowrap;
}
.btn:active { transform: translateY(1px); }

.btn--primary {
  color: #fff;
  background: var(--gradient-brand);
}
.btn--primary:hover { transform: translateY(-2px); }

.btn--ghost {
  color: var(--ink-800);
  background: #fff;
  border-color: var(--border-strong);
}
.btn--ghost:hover { border-color: var(--violet-500); color: var(--violet-700); transform: translateY(-2px); }

.btn--sm { padding: 9px 20px; font-size: 0.88rem; }
.btn--lg { padding: 17px 42px; font-size: 1.05rem; }

/* ---------- Link arrow ---------- */
.link-arrow {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-weight: 600;
  font-size: 0.92rem;
  color: var(--violet-700);
}
.link-arrow svg { transition: transform 0.18s ease; }
.link-arrow:hover svg { transform: translateX(4px); }

/* ============================================================
   Header
   ============================================================ */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(255, 255, 255, 0.82);
  backdrop-filter: saturate(180%) blur(14px);
  border-bottom: 1px solid var(--border);
}
.site-header__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 74px;
  gap: 24px;
}

.brand { display: inline-flex; align-items: center; }
.brand__logo { height: 46px; width: auto; display: block; }

.nav { display: flex; align-items: center; gap: 34px; }
.nav__link {
  font-weight: 500;
  font-size: 0.95rem;
  color: var(--slate-600);
  position: relative;
}
.nav__link::after {
  content: "";
  position: absolute;
  left: 0; bottom: -6px;
  width: 0; height: 2px;
  border-radius: 2px;
  background: var(--gradient-brand);
  transition: width 0.2s ease;
}
.nav__link:hover { color: var(--ink-900); }
.nav__link:hover::after { width: 100%; }

.header__actions { display: flex; align-items: center; gap: 12px; }

.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  width: 42px; height: 42px;
  border: 1px solid var(--border-strong);
  border-radius: 10px;
  background: #fff;
  cursor: pointer;
  align-items: center;
  justify-content: center;
}
.nav-toggle span {
  display: block;
  width: 18px; height: 2px;
  background: var(--ink-800);
  border-radius: 2px;
}

/* ============================================================
   Hero
   ============================================================ */
.hero {
  position: relative;
  text-align: center;
  padding-block: 92px 80px;
  overflow: hidden;
  background:
    radial-gradient(60% 50% at 18% 100%, rgba(90, 31, 115, 0.16), transparent 60%),
    radial-gradient(55% 50% at 88% 92%, rgba(242, 82, 157, 0.14), transparent 60%),
    var(--bg);
}
.hero__eyebrow { justify-content: center; }
.hero h1 {
  font-size: clamp(2.6rem, 5.4vw, 4rem);
  font-weight: 700;
  max-width: 22ch;
  margin-inline: auto;
}
.hero__sub {
  margin: 22px auto 0;
  max-width: 560px;
  font-size: 1.12rem;
  color: var(--slate-500);
}
.hero__actions {
  display: flex;
  justify-content: center;
  gap: 14px;
  margin-top: 34px;
  flex-wrap: wrap;
}

.hero__preview {
  margin: 64px auto 0;
  max-width: 1040px;
  border-radius: var(--radius-lg);
  border: 1px solid var(--border);
  box-shadow: var(--shadow-lg);
  overflow: hidden;
  background: #fff;
}
.hero__preview img {
  display: block;
  width: 100%;
  height: auto;
}

/* ============================================================
   Products
   ============================================================ */
.product-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 28px;
}
.product-card {
  background: #fff;
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 38px 36px;
  box-shadow: var(--shadow-sm);
  transition: transform 0.2s ease, box-shadow 0.2s ease, border-color 0.2s ease;
}
.product-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
  border-color: var(--border-strong);
}
.product-card__icon {
  width: 54px; height: 54px;
  border-radius: 14px;
  display: grid;
  place-items: center;
  background: var(--gradient-brand-soft);
  color: var(--violet-600);
  margin-bottom: 22px;
}
.product-card__tag {
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--violet-700);
  margin-bottom: 10px;
}
.product-card h3 { font-size: 1.5rem; font-weight: 700; margin-bottom: 12px; }
.product-card p:not(.product-card__tag) { margin: 0 0 22px; color: var(--slate-500); }

/* ============================================================
   Testimonials
   ============================================================ */
.testimonial-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 24px;
}
.testimonial {
  position: relative;
  margin: 0;
  background: #fff;
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 34px 34px 30px;
}
.testimonial__quote-mark {
  font-family: var(--font-display);
  font-size: 3.4rem;
  line-height: 1;
  font-weight: 700;
  background: var(--gradient-brand);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  opacity: 0.28;
  margin-bottom: 8px;
}
.testimonial__text {
  font-style: italic;
  color: var(--ink-700);
  font-size: 1.02rem;
  margin: 0 0 24px;
}
.testimonial__author { display: flex; align-items: center; gap: 14px; }
.testimonial__avatar {
  width: 46px; height: 46px;
  border-radius: 50%;
  flex: none;
  background: var(--gradient-brand-soft);
  display: grid;
  place-items: center;
  color: var(--violet-600);
}
.testimonial__name { font-weight: 700; color: var(--ink-900); font-size: 0.98rem; }
.testimonial__role { font-size: 0.86rem; color: var(--slate-500); }
.testimonial__org { font-size: 0.86rem; color: var(--slate-400); }

/* ============================================================
   Featured testimonial (spotlight)
   ============================================================ */
.spotlight {
  position: relative;
  margin: 0;
  display: grid;
  grid-template-columns: 1fr 380px;
  min-height: 460px;
  background: var(--bg-soft);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-sm);
}
/* soft diagonal sheen on the left, echoing the reference */
.spotlight::before {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(118deg, rgba(255, 255, 255, 0.9) 0%, rgba(246, 247, 252, 0) 46%);
  pointer-events: none;
}
.spotlight__body {
  position: relative;
  z-index: 1;
  display: flex;
  flex-direction: column;
  padding: 56px 60px;
}
.spotlight__logo {
  font-family: var(--font-display);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.32em;
  font-size: 0.9rem;
  color: var(--slate-400);
}
.spotlight__quote {
  margin: auto 0;
  padding: 36px 0;
  font-family: var(--font-display);
  font-weight: 500;
  font-size: clamp(1.4rem, 2vw, 1.9rem);
  line-height: 1.42;
  letter-spacing: -0.01em;
  color: var(--ink-900);
  max-width: 660px;
}
.spotlight__quote mark {
  background: var(--magenta-500);
  color: var(--ink-900);
  padding: 0.04em 0.14em;
  border-radius: 2px;
  box-decoration-break: clone;
  -webkit-box-decoration-break: clone;
}
.spotlight__author { display: flex; flex-direction: column; gap: 4px; }
.spotlight__name { font-weight: 700; color: var(--ink-900); font-size: 1.05rem; }
.spotlight__role { color: var(--slate-500); font-size: 0.95rem; }

.spotlight__media { position: relative; padding: 24px 24px 24px 0; }
.spotlight__photo {
  display: block;
  width: 100%;
  height: 100%;
  border-radius: 14px;
  object-fit: cover;
  object-position: center 20%;
}

@media (max-width: 820px) {
  .spotlight { grid-template-columns: 1fr; min-height: 0; }
  .spotlight__body { padding: 40px 32px; order: 2; }
  .spotlight__media { order: 1; padding: 0; min-height: 240px; }
  .spotlight__photo { border-radius: 0; }
}

/* ============================================================
   Publications
   ============================================================ */
.pub-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 26px;
}
.pub-card {
  background: #fff;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: var(--shadow-sm);
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}
.pub-card:hover { transform: translateY(-4px); box-shadow: var(--shadow-md); }
.pub-card__thumb {
  aspect-ratio: 16 / 9;
  display: grid;
  place-items: center;
  color: var(--slate-300);
  background: linear-gradient(135deg, #f1eefb 0%, #f9f1f6 100%);
  border-bottom: 1px solid var(--border);
}
.pub-card__body { padding: 24px 24px 28px; }
.pub-card__tag {
  font-size: 0.7rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--violet-600);
}
.pub-card h3 {
  font-size: 1.05rem;
  font-weight: 600;
  line-height: 1.35;
  margin: 12px 0 16px;
  color: var(--ink-800);
}
.pub-card__date { font-size: 0.84rem; color: var(--slate-400); }

/* ============================================================
   CTA with video background
   ============================================================ */
.cta {
  position: relative;
  isolation: isolate;
  overflow: hidden;
  text-align: center;
  padding-block: 128px;
  background: var(--ink-900); /* fallback until video paints */
}
.cta__video {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  z-index: -2;
}
.cta__overlay {
  position: absolute;
  inset: 0;
  z-index: -1;
  background: rgba(0, 0, 0, 0.6);
}
.cta__inner { position: relative; }
.cta__title {
  color: #fff;
  font-size: clamp(2.1rem, 4vw, 3.1rem);
  font-weight: 700;
}
.cta__sub {
  margin: 18px auto 0;
  max-width: 560px;
  font-size: 1.12rem;
  color: rgba(255, 255, 255, 0.86);
}
.cta .btn--lg { margin-top: 34px; }

/* ============================================================
   Footer
   ============================================================ */
.site-footer {
  background: var(--ink-900);
  color: #b9bfd6;
  padding-block: 64px 30px;
}
.footer__top {
  display: grid;
  grid-template-columns: 1.6fr repeat(3, 1fr);
  gap: 40px;
  padding-bottom: 48px;
  border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}
.footer__brand .brand__logo { height: 40px; }
.footer__tagline { margin: 18px 0 0; font-size: 0.95rem; color: #8c93b0; max-width: 240px; }

.footer__col h4 {
  color: #fff;
  font-family: var(--font-body);
  font-size: 0.78rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  margin: 0 0 18px;
}
.footer__col li { margin-bottom: 12px; }
.footer__col a { font-size: 0.95rem; color: #b9bfd6; transition: color 0.18s ease; }
.footer__col a:hover { color: #fff; }

.footer__bottom {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-top: 26px;
  gap: 16px;
  flex-wrap: wrap;
}
.footer__copy { font-size: 0.86rem; color: #767d9b; }
.footer__social { display: flex; gap: 22px; }
.footer__social a { font-size: 0.86rem; color: #b9bfd6; }
.footer__social a:hover { color: #fff; }

/* ============================================================
   Responsive
   ============================================================ */
@media (max-width: 900px) {
  .product-grid,
  .testimonial-grid { grid-template-columns: 1fr; }
  .pub-grid { grid-template-columns: 1fr; }
  .footer__top { grid-template-columns: 1fr 1fr; }
}

@media (max-width: 760px) {
  .section { padding-block: 64px; }
  .nav, .header__actions .btn { display: none; }
  .nav-toggle { display: inline-flex; }

  .nav.is-open {
    display: flex;
    flex-direction: column;
    position: absolute;
    top: 74px; left: 0; right: 0;
    background: #fff;
    border-bottom: 1px solid var(--border);
    padding: 20px 24px 28px;
    gap: 18px;
    align-items: flex-start;
    box-shadow: var(--shadow-md);
  }
  .footer__top { grid-template-columns: 1fr; gap: 32px; }
}

@media (max-width: 420px) {
  .hero__actions .btn { width: 100%; }
}