:root {
  --bg: #ffffff;
  --surface: #f4f5f7;
  --ink: #12151a;
  --muted: #5b6270;
  --line: #e2e4e9;
  --accent: #3546e0;
  --accent-ink: #ffffff;
  --signal: #17b26a;

  --font-display: "Space Grotesk", sans-serif;
  --font-body: "IBM Plex Sans", sans-serif;
  --font-mono: "IBM Plex Mono", monospace;

  --content-width: 720px;
  --page-pad: 24px;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
  * {
    animation-duration: 0.01ms !important;
    transition-duration: 0.01ms !important;
  }
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--font-body);
  font-size: 17px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

a {
  color: inherit;
}

h1, h2, h3 {
  font-family: var(--font-display);
  font-weight: 600;
  margin: 0;
  letter-spacing: -0.01em;
}

p {
  margin: 0;
}

ul {
  list-style: none;
  margin: 0;
  padding: 0;
}

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

/* Header */

.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 20px var(--page-pad);
  background: rgba(255, 255, 255, 0.85);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--line);
}

.mark {
  font-family: var(--font-mono);
  font-weight: 500;
  font-size: 15px;
  text-decoration: none;
  color: var(--ink);
}

.nav {
  display: flex;
  gap: 28px;
}

.nav a {
  text-decoration: none;
  font-size: 15px;
  color: var(--muted);
  transition: color 0.15s ease;
}

.nav a:hover {
  color: var(--ink);
}

/* Sections shared */

main {
  max-width: var(--content-width);
  margin: 0 auto;
  padding: 0 var(--page-pad);
}

section {
  padding: 80px 0;
  border-bottom: 1px solid var(--line);
}

section:last-of-type {
  border-bottom: none;
}

.section-head {
  margin-bottom: 40px;
}

.section-head h2 {
  font-size: 26px;
  margin-bottom: 8px;
}

.section-head p {
  color: var(--muted);
}

/* Hero */

.hero {
  padding-top: 96px;
  padding-bottom: 88px;
}

.hero-kicker {
  font-family: var(--font-mono);
  font-size: 14px;
  color: var(--signal);
  height: 20px;
  margin-bottom: 20px;
}

.hero-kicker::before {
  content: "● ";
}

.hero-name {
  font-size: clamp(38px, 6vw, 56px);
  line-height: 1.05;
}

.hero-role {
  font-family: var(--font-display);
  font-size: clamp(18px, 2.4vw, 22px);
  color: var(--accent);
  margin-top: 10px;
  font-weight: 500;
}

.hero-sub {
  max-width: 52ch;
  color: var(--muted);
  font-size: 18px;
  margin-top: 20px;
}

.tag-list {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 28px;
}

.tag-list li {
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--muted);
  border: 1px solid var(--line);
  border-radius: 4px;
  padding: 5px 10px;
}

.hero-actions {
  display: flex;
  gap: 14px;
  margin-top: 36px;
}

.btn {
  display: inline-block;
  padding: 12px 20px;
  border-radius: 4px;
  font-size: 15px;
  font-weight: 500;
  text-decoration: none;
  border: 1px solid transparent;
  transition: background 0.15s ease, border-color 0.15s ease, color 0.15s ease;
}

.btn-primary {
  background: var(--accent);
  color: var(--accent-ink);
}

.btn-primary:hover {
  background: #2938c2;
}

.btn-ghost {
  border-color: var(--line);
  color: var(--ink);
}

.btn-ghost:hover {
  border-color: var(--ink);
}

/* About */

.about h2 {
  font-size: 26px;
  margin-bottom: 20px;
}

.about p {
  max-width: 62ch;
  color: var(--muted);
  font-size: 17px;
}

/* Products */

.product-list {
  display: flex;
  flex-direction: column;
  gap: 36px;
}

.product-head {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 16px;
  flex-wrap: wrap;
  margin-bottom: 8px;
}

.product-head h3 {
  font-size: 20px;
}

.product-link {
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--accent);
  text-decoration: none;
  white-space: nowrap;
}

.product-link:hover {
  text-decoration: underline;
}

.product p {
  color: var(--muted);
  max-width: 60ch;
}

/* Studies */

.study-list {
  display: flex;
  flex-direction: column;
}

.study-list li {
  border-top: 1px solid var(--line);
}

.study-list li:last-child {
  border-bottom: 1px solid var(--line);
}

.study-list a {
  display: flex;
  flex-direction: column;
  gap: 4px;
  padding: 18px 0;
  text-decoration: none;
}

.study-name {
  font-family: var(--font-mono);
  font-size: 14px;
  color: var(--ink);
}

.study-desc {
  font-size: 15px;
  color: var(--muted);
  max-width: 60ch;
}

.study-list a:hover .study-name {
  color: var(--accent);
}

/* Contact */

.contact h2 {
  font-size: 26px;
  margin-bottom: 12px;
}

.contact > p {
  color: var(--muted);
  margin-bottom: 28px;
}

.contact-list {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.contact-list a {
  font-family: var(--font-mono);
  font-size: 16px;
  text-decoration: none;
  color: var(--ink);
}

.contact-list a:hover {
  color: var(--accent);
}

/* Footer */

.site-footer {
  padding: 28px var(--page-pad) 40px;
  text-align: center;
}

.site-footer p {
  color: var(--muted);
  font-size: 13px;
}

/* Mobile */

@media (max-width: 640px) {
  .nav {
    gap: 16px;
  }

  .nav a {
    font-size: 13px;
  }

  section {
    padding: 56px 0;
  }

  .hero {
    padding-top: 56px;
  }

  .product-head {
    flex-direction: column;
    align-items: flex-start;
    gap: 4px;
  }
}