/* Alteron Therapeutics — site styles */

:root {
  --brand: #0013da;          /* logo blue */
  --brand-600: #1f33e6;
  --brand-700: #000fa8;
  --brand-50: #f2f4ff;
  --brand-100: #e4e8ff;
  --violet: #6b4fd8;          /* from the molecule imagery */
  --ink: #0b1030;
  --ink-2: #3b4163;
  --ink-3: #6a7090;
  --line: #e3e6f2;
  --bg: #ffffff;
  --bg-soft: #f7f8fd;
  --radius: 16px;
  --radius-sm: 10px;
  --shadow: 0 1px 2px rgba(11, 16, 48, .04), 0 8px 24px rgba(11, 16, 48, .06);
  --shadow-lg: 0 2px 4px rgba(11, 16, 48, .04), 0 24px 48px rgba(11, 16, 48, .10);
  --max: 1200px;
  --gutter: clamp(16px, 5vw, 48px);
  --header-h: 72px;
  --font: "Inter", system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
}

*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: calc(var(--header-h) + 16px); }
body {
  margin: 0;
  font-family: var(--font);
  font-size: 1.0625rem;
  line-height: 1.65;
  color: var(--ink-2);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}
img, svg { display: block; max-width: 100%; }
a { color: inherit; text-decoration: none; }
p { margin: 0; }
h1, h2, h3, h4, h5, h6 { margin: 0; color: var(--ink); line-height: 1.15; letter-spacing: -0.02em; font-weight: 700; }
h1 { font-size: clamp(2.25rem, 5vw, 3.75rem); letter-spacing: -0.03em; }
h2 { font-size: clamp(1.875rem, 3.6vw, 2.75rem); }
h3 { font-size: clamp(1.5rem, 2.6vw, 2rem); }
.h5 { font-size: 1.25rem; line-height: 1.35; letter-spacing: -0.01em; }

.container { width: 100%; max-width: var(--max); margin: 0 auto; padding: 0 var(--gutter); }
.section { padding: clamp(64px, 9vw, 112px) 0; }
.section--soft { background: var(--bg-soft); }
.center { text-align: center; }
.measure { max-width: 760px; }
.center.measure { margin-left: auto; margin-right: auto; }
.text-brand { color: var(--brand); }
.lead { font-size: clamp(1.0625rem, 1.6vw, 1.25rem); line-height: 1.6; }
.eyebrow {
  display: inline-flex; align-items: center; gap: 8px;
  font-size: .8125rem; font-weight: 600; letter-spacing: .08em; text-transform: uppercase;
  color: var(--brand);
}
.eyebrow::before { content: ""; width: 20px; height: 2px; background: currentColor; border-radius: 2px; }
.stack-sm > * + * { margin-top: 12px; }
.stack > * + * { margin-top: 20px; }
.stack-lg > * + * { margin-top: 32px; }
.skip-link { position: absolute; left: -9999px; top: 8px; z-index: 100; background: var(--brand); color: #fff; padding: 8px 14px; border-radius: 8px; }
.skip-link:focus { left: 8px; }

/* ---------- Buttons ---------- */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  padding: 14px 26px; border-radius: 999px;
  font-weight: 600; font-size: 1rem; line-height: 1;
  border: 1px solid transparent; cursor: pointer;
  transition: background-color .2s, color .2s, border-color .2s, transform .2s, box-shadow .2s;
}
.btn svg { width: 18px; height: 18px; }
.btn--primary { background: var(--brand); color: #fff; box-shadow: 0 6px 20px rgba(0, 19, 218, .25); }
.btn--primary:hover { background: var(--brand-700); transform: translateY(-1px); }
.btn--light { background: #fff; color: var(--brand); }
.btn--light:hover { background: var(--brand-50); transform: translateY(-1px); }
.btn--ghost { background: transparent; color: var(--brand); border-color: var(--brand-100); }
.btn--ghost:hover { background: var(--brand-50); border-color: var(--brand); }
.link-arrow {
  display: inline-flex; align-items: center; gap: 6px;
  font-weight: 600; color: var(--brand);
}
.link-arrow svg { width: 16px; height: 16px; transition: transform .2s; }
.link-arrow:hover svg { transform: translateX(3px); }
:focus-visible { outline: 3px solid rgba(0, 19, 218, .45); outline-offset: 3px; border-radius: 6px; }

/* ---------- Header ---------- */
.site-header {
  position: sticky; top: 0; z-index: 50;
  background: rgba(255, 255, 255, .88);
  backdrop-filter: saturate(180%) blur(14px);
  -webkit-backdrop-filter: saturate(180%) blur(14px);
  border-bottom: 1px solid transparent;
  transition: border-color .2s, box-shadow .2s;
}
.site-header.is-scrolled { border-bottom-color: var(--line); box-shadow: 0 4px 20px rgba(11, 16, 48, .05); }
.nav { display: flex; align-items: center; justify-content: space-between; height: var(--header-h); }
.nav__logo img { height: 40px; width: auto; }
.nav__menu { display: flex; align-items: center; gap: 4px; list-style: none; margin: 0; padding: 0; }
.nav__link, .nav__dropdown-toggle {
  display: inline-flex; align-items: center; gap: 6px;
  padding: 10px 16px; border-radius: 999px;
  font: inherit; font-size: .9875rem; font-weight: 500; color: var(--ink);
  background: none; border: 0; cursor: pointer;
  transition: background-color .2s, color .2s;
}
.nav__link:hover, .nav__dropdown-toggle:hover { background: var(--brand-50); color: var(--brand); }
.nav__link[aria-current="page"], .nav__dropdown.is-current > .nav__dropdown-toggle { color: var(--brand); }
.nav__dropdown { position: relative; }
.nav__dropdown-toggle svg { width: 14px; height: 14px; transition: transform .2s; }
.nav__dropdown[data-open="true"] .nav__dropdown-toggle svg { transform: rotate(180deg); }
.nav__dropdown-menu {
  position: absolute; top: calc(100% + 8px); right: 0; min-width: 200px;
  list-style: none; margin: 0; padding: 8px;
  background: #fff; border: 1px solid var(--line); border-radius: 14px; box-shadow: var(--shadow-lg);
  opacity: 0; visibility: hidden; transform: translateY(-4px);
  transition: opacity .18s, transform .18s, visibility .18s;
}
.nav__dropdown[data-open="true"] .nav__dropdown-menu { opacity: 1; visibility: visible; transform: none; }
.nav__dropdown-menu a {
  display: block; padding: 10px 14px; border-radius: 8px;
  font-size: .9875rem; font-weight: 500; color: var(--ink);
}
.nav__dropdown-menu a:hover { background: var(--brand-50); color: var(--brand); }
.nav__dropdown-menu a[aria-current="page"] { color: var(--brand); background: var(--brand-50); }
.nav__toggle { display: none; }

@media (max-width: 820px) {
  .nav__logo img { height: 34px; }
  .nav__toggle {
    display: inline-flex; align-items: center; justify-content: center;
    width: 44px; height: 44px; border-radius: 12px;
    background: none; border: 1px solid var(--line); color: var(--ink); cursor: pointer;
  }
  .nav__toggle svg { width: 22px; height: 22px; }
  .nav__toggle .icon-close { display: none; }
  .site-header[data-menu-open="true"] .nav__toggle .icon-open { display: none; }
  .site-header[data-menu-open="true"] .nav__toggle .icon-close { display: block; }
  .nav__panel {
    position: fixed; inset: var(--header-h) 0 auto 0;
    background: #fff; border-bottom: 1px solid var(--line); box-shadow: var(--shadow-lg);
    padding: 12px var(--gutter) 24px;
    display: none;
  }
  .site-header[data-menu-open="true"] .nav__panel { display: block; }
  .nav__menu { flex-direction: column; align-items: stretch; gap: 2px; }
  .nav__link, .nav__dropdown-toggle { width: 100%; justify-content: space-between; padding: 14px 12px; border-radius: 10px; font-size: 1.0625rem; }
  .nav__dropdown-menu {
    position: static; opacity: 1; visibility: visible; transform: none;
    border: 0; box-shadow: none; padding: 0 0 0 12px; display: none;
  }
  .nav__dropdown[data-open="true"] .nav__dropdown-menu { display: block; }
}

/* ---------- Hero (image) ---------- */
.hero {
  position: relative; isolation: isolate; overflow: hidden;
  color: #fff;
  min-height: clamp(520px, 78vh, 760px);
  display: flex; align-items: center;
}
.hero--sub { min-height: clamp(420px, 60vh, 560px); }
.hero__bg { position: absolute; inset: 0; z-index: -2; width: 100%; height: 100%; object-fit: cover; }
.hero::before {
  content: ""; position: absolute; inset: 0; z-index: -1;
  background:
    linear-gradient(100deg, rgba(5, 9, 60, .88) 0%, rgba(8, 14, 110, .70) 42%, rgba(40, 24, 140, .25) 100%);
}
.hero h1 { color: #fff; max-width: 15ch; }
.hero--sub h1 { max-width: 22ch; font-size: clamp(2rem, 4.4vw, 3.25rem); }
.hero .lead { color: rgba(255, 255, 255, .86); max-width: 52ch; }
.hero .eyebrow { color: #c9ceff; }
.hero__content > * + * { margin-top: 24px; }
.hero__content .btn { margin-top: 36px; }

/* ---------- Page header (no image) ---------- */
.page-head {
  position: relative; overflow: hidden;
  padding: clamp(72px, 10vw, 128px) 0 clamp(56px, 8vw, 96px);
  background:
    radial-gradient(60% 80% at 85% 0%, rgba(107, 79, 216, .14) 0%, transparent 60%),
    radial-gradient(50% 70% at 0% 100%, rgba(0, 19, 218, .10) 0%, transparent 60%),
    var(--bg-soft);
  border-bottom: 1px solid var(--line);
}
.page-head h1 { color: var(--ink); }
.page-head h1 .text-brand { color: var(--brand); }
.page-head > .container > * + * { margin-top: 20px; }
.page-head .btn { margin-top: 32px; }

/* ---------- Home: 4-step feature scroller ---------- */
.steps { display: grid; grid-template-columns: 260px 1fr; gap: clamp(32px, 6vw, 88px); align-items: start; }
.steps__nav { position: sticky; top: calc(var(--header-h) + 40px); list-style: none; margin: 0; padding: 0; }
.steps__nav li + li { margin-top: 4px; }
.steps__nav a {
  display: flex; align-items: baseline; gap: 16px;
  padding: 16px 18px; border-radius: 12px;
  color: var(--ink-3); font-weight: 600;
  border-left: 3px solid var(--line);
  border-top-left-radius: 0; border-bottom-left-radius: 0;
  transition: color .2s, background-color .2s, border-color .2s;
}
.steps__nav a span { font-size: .875rem; font-variant-numeric: tabular-nums; }
.steps__nav a:hover { color: var(--ink); background: var(--bg-soft); }
.steps__nav a.is-active { color: var(--brand); border-left-color: var(--brand); background: var(--brand-50); }
.step { display: grid; grid-template-columns: minmax(0, 5fr) minmax(0, 6fr); gap: clamp(24px, 4vw, 48px); align-items: center; padding-bottom: clamp(56px, 8vw, 96px); }
.step:last-child { padding-bottom: 0; }
.step__media { border-radius: var(--radius); overflow: hidden; aspect-ratio: 1 / 1; background: var(--brand-50); box-shadow: var(--shadow); }
.step__media img { width: 100%; height: 100%; object-fit: cover; transition: transform .8s cubic-bezier(.2, .7, .2, 1); }
.step:hover .step__media img { transform: scale(1.03); }
.step__label { display: none; }
@media (max-width: 640px) { .step { grid-template-columns: 1fr; } .step__media { aspect-ratio: 4 / 3; } }
.step h2 { color: var(--brand); font-size: clamp(1.625rem, 2.6vw, 2.125rem); }
.step p { max-width: 62ch; }

@media (max-width: 900px) {
  .steps { grid-template-columns: 1fr; }
  .steps__nav { display: none; }
  .step__label { display: inline-flex; }
}

/* ---------- Cards ---------- */
.grid-2 { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 24px; }
.grid-3 { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 24px; }
.grid-4 { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 24px; }
@media (max-width: 980px) { .grid-3, .grid-4 { grid-template-columns: repeat(2, minmax(0, 1fr)); } }
@media (max-width: 640px) { .grid-2, .grid-3, .grid-4 { grid-template-columns: 1fr; } }

.card {
  position: relative; display: flex; flex-direction: column; gap: 16px;
  background: #fff; border: 1px solid var(--line); border-radius: var(--radius);
  padding: clamp(24px, 3vw, 36px);
  transition: transform .25s, box-shadow .25s, border-color .25s;
}
.card:hover { transform: translateY(-3px); box-shadow: var(--shadow-lg); border-color: var(--brand-100); }
.card .link-arrow { margin-top: auto; padding-top: 8px; }
.icon-badge {
  display: inline-flex; align-items: center; justify-content: center;
  width: 52px; height: 52px; border-radius: 14px;
  background: linear-gradient(135deg, var(--brand-50), #efeaff);
  color: var(--brand);
}
.icon-badge svg { width: 26px; height: 26px; }
.section-head { margin-bottom: clamp(40px, 6vw, 64px); }

/* ---------- Contact ---------- */
.contact { display: grid; grid-template-columns: minmax(0, 5fr) minmax(0, 7fr); gap: clamp(32px, 6vw, 80px); align-items: center; }
.contact__items { display: grid; gap: 28px; margin-top: 40px; }
.contact__item { display: flex; gap: 16px; }
.contact__item h6 { font-size: 1.0625rem; letter-spacing: 0; margin-bottom: 4px; }
.contact__item a { color: var(--brand); font-weight: 500; }
.contact__item a:hover { text-decoration: underline; text-underline-offset: 3px; }
.contact__item .icon-badge { flex: none; width: 44px; height: 44px; border-radius: 12px; }
.contact__item .icon-badge svg { width: 22px; height: 22px; }
.contact__map { border-radius: var(--radius); overflow: hidden; border: 1px solid var(--line); box-shadow: var(--shadow); }
.contact__map img { width: 100%; height: auto; }
@media (max-width: 860px) { .contact { grid-template-columns: 1fr; } }

/* ---------- Science: split rows ---------- */
.split { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: clamp(32px, 6vw, 88px); align-items: center; }
.split + .split { margin-top: clamp(64px, 9vw, 112px); }
.split--reverse .split__media { order: -1; }
.split__media { background: #fff; border: 1px solid var(--line); border-radius: var(--radius); padding: clamp(12px, 2vw, 24px); box-shadow: var(--shadow); }
.split__media img { width: 100%; height: auto; border-radius: var(--radius-sm); }
@media (max-width: 860px) {
  .split { grid-template-columns: 1fr; }
  .split--reverse .split__media { order: 0; }
}

/* ---------- Science: timeline ---------- */
.timeline-head { display: flex; flex-wrap: wrap; align-items: end; justify-content: space-between; gap: 24px; margin-bottom: clamp(40px, 6vw, 64px); }
.timeline-head h2 { max-width: 18ch; }
.timeline { position: relative; display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 24px; list-style: none; margin: 0; padding: 0; }
.timeline::before {
  content: ""; position: absolute; left: 0; right: 0; top: 26px; height: 2px;
  background: linear-gradient(90deg, var(--brand), var(--violet));
  opacity: .25;
}
.timeline li { position: relative; }
.timeline .icon-badge { position: relative; background: #fff; border: 2px solid var(--brand-100); box-shadow: 0 0 0 6px var(--bg-soft); }
.timeline h6 { margin-top: 24px; color: var(--brand-700); font-size: 1.125rem; letter-spacing: -0.01em; }
.timeline p { margin-top: 8px; font-size: 1rem; }
@media (max-width: 900px) {
  .timeline { grid-template-columns: 1fr; gap: 32px; padding-left: 0; }
  .timeline::before { left: 26px; right: auto; top: 0; bottom: 0; width: 2px; height: auto; background: linear-gradient(180deg, var(--brand), var(--violet)); }
  .timeline li { display: grid; grid-template-columns: 52px 1fr; column-gap: 20px; }
  .timeline h6 { margin-top: 2px; grid-column: 2; }
  .timeline .icon-badge { grid-row: span 2; }
  .timeline p { grid-column: 2; }
}

/* ---------- CTA panel ---------- */
.cta-panel {
  position: relative; overflow: hidden; isolation: isolate;
  border-radius: calc(var(--radius) + 8px);
  padding: clamp(40px, 7vw, 88px) clamp(24px, 6vw, 80px);
  background: linear-gradient(135deg, #07107a 0%, var(--brand) 55%, var(--violet) 130%);
  color: rgba(255, 255, 255, .88);
  text-align: center;
}
.cta-panel::after {
  content: ""; position: absolute; inset: -40% -10% auto auto; width: 60%; aspect-ratio: 1; z-index: -1;
  background: radial-gradient(circle, rgba(255, 255, 255, .18), transparent 60%);
}
.cta-panel h2 { color: #fff; }
.cta-panel > * + * { margin-top: 20px; }
.cta-panel p { max-width: 60ch; margin-left: auto; margin-right: auto; }
.cta-panel .btn { margin-top: 36px; }

/* ---------- People ---------- */
.team { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 24px; }
@media (max-width: 760px) { .team { grid-template-columns: 1fr; } }
.person { flex-direction: row; gap: 24px; align-items: flex-start; }
.person__photo {
  flex: none; width: 96px; height: 96px; border-radius: 50%; object-fit: cover;
  background: var(--brand-50); box-shadow: 0 0 0 4px #fff, 0 0 0 5px var(--brand-100);
}
.person__body { display: flex; flex-direction: column; gap: 4px; min-width: 0; flex: 1; }
.person__name { font-size: 1.25rem; font-weight: 700; color: var(--ink); letter-spacing: -0.01em; }
.person__role { font-weight: 600; color: var(--brand); font-size: .9875rem; }
.person__bio { list-style: none; margin: 12px 0 0; padding: 0; font-size: .9875rem; }
.person__bio li { position: relative; padding-left: 16px; }
.person__bio li + li { margin-top: 6px; }
.person__bio li::before { content: ""; position: absolute; left: 0; top: .7em; width: 6px; height: 6px; border-radius: 50%; background: var(--brand-100); }
.person__social { margin-top: 16px; display: inline-flex; width: 36px; height: 36px; align-items: center; justify-content: center; border-radius: 10px; color: var(--ink-3); border: 1px solid var(--line); transition: color .2s, border-color .2s, background-color .2s; }
.person__social:hover { color: var(--brand); border-color: var(--brand-100); background: var(--brand-50); }
.person__social svg { width: 20px; height: 20px; }
@media (max-width: 480px) { .person { flex-direction: column; } }

.logos { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 16px; align-items: stretch; margin-top: 40px; }
.logos li { display: flex; align-items: center; justify-content: center; padding: 20px 24px; height: 112px; background: #fff; border: 1px solid var(--line); border-radius: var(--radius-sm); }
.logos img { max-height: 64px; width: auto; object-fit: contain; filter: grayscale(1); opacity: .75; transition: filter .25s, opacity .25s; }
.logos li:hover img { filter: none; opacity: 1; }
.logos { list-style: none; padding: 0; }
@media (max-width: 760px) { .logos { grid-template-columns: repeat(2, minmax(0, 1fr)); } }

/* ---------- Footer ---------- */
.site-footer { background: #070b2e; color: rgba(255, 255, 255, .72); padding: clamp(56px, 8vw, 88px) 0 32px; font-size: .9875rem; }
.footer__top { display: grid; grid-template-columns: minmax(0, 1.4fr) repeat(3, minmax(0, 1fr)); gap: 40px; }
.footer__brand img { height: 40px; width: auto; filter: brightness(0) invert(1); }
.footer__brand p { margin-top: 20px; }
.footer__brand strong { display: block; color: #fff; font-weight: 600; margin-bottom: 4px; }
.footer__brand a:hover { color: #fff; }
.footer__col h4 { color: #fff; font-size: .9375rem; font-weight: 600; letter-spacing: 0; margin-bottom: 16px; }
.footer__col ul { list-style: none; margin: 0; padding: 0; }
.footer__col li + li { margin-top: 10px; }
.footer__col a { display: inline-flex; align-items: center; gap: 10px; transition: color .2s; }
.footer__col a:hover { color: #fff; }
.footer__col svg { width: 18px; height: 18px; }
.footer__bottom { margin-top: 56px; padding-top: 24px; border-top: 1px solid rgba(255, 255, 255, .1); font-size: .875rem; color: rgba(255, 255, 255, .5); }
@media (max-width: 860px) { .footer__top { grid-template-columns: 1fr 1fr; } .footer__brand { grid-column: 1 / -1; } }
@media (max-width: 420px) { .footer__top { grid-template-columns: 1fr; } }

/* ---------- Motion ---------- */
.reveal { opacity: 0; transform: translateY(18px); transition: opacity .7s ease, transform .7s cubic-bezier(.2, .7, .2, 1); }
.reveal.is-visible { opacity: 1; transform: none; }
.no-js .reveal { opacity: 1; transform: none; }
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .reveal { opacity: 1; transform: none; transition: none; }
  *, *::before, *::after { transition-duration: 0s !important; animation-duration: 0s !important; }
}