:root {
  --navy: #112b46;
  --blue: #1f5b87;
  --light-blue: #eaf3f8;
  --gold: #c89b3c;
  --text: #333;
  --muted: #6d7780;
  --white: #fff;
  --border: #dce3e8;
  --max-width: 1180px;
}

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

html {
  scroll-behavior: smooth;
}

body {
  color: var(--text);
  background: var(--white);
  font-family: "Montserrat", sans-serif;
  line-height: 1.7;
}

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

img {
  display: block;
  max-width: 100%;
}

button,
input,
textarea {
  font: inherit;
}

.container {
  width: min(100% - 40px, var(--max-width));
  margin: 0 auto;
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

/* Top bar */

.topbar {
  background: var(--navy);
  color: white;
  font-size: 12px;
  padding: 9px 0;
}

.topbar-content {
  display: flex;
  justify-content: space-between;
  gap: 20px;
}

/* Header and navigation */

.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  background: rgba(255, 255, 255, 0.97);
  border-bottom: 1px solid var(--border);
}

.nav {
  min-height: 80px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 30px;
}

.brand {
  color: var(--navy);
  font-family: "Playfair Display", serif;
  font-size: 23px;
  font-weight: 600;
  line-height: 1.1;
}

.brand span {
  display: block;
  color: var(--gold);
  font-family: "Montserrat", sans-serif;
  font-size: 10px;
  font-weight: 600;
  letter-spacing: 2px;
  margin-top: 5px;
  text-transform: uppercase;
}

.nav-links {
  display: flex;
  list-style: none;
  gap: 27px;
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.5px;
  text-transform: uppercase;
}

.nav-links a {
  transition: color 0.2s ease;
}

.nav-links a:hover,
.nav-links a:focus {
  color: var(--gold);
}

.menu-button {
  display: none;
  border: 0;
  background: none;
  color: var(--navy);
  cursor: pointer;
  font-size: 25px;
}

/* General sections */

section {
  padding: 95px 0;
}

.eyebrow {
  color: var(--gold);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 3px;
  text-transform: uppercase;
}

.section-heading {
  margin-bottom: 45px;
  text-align: center;
}

.section-heading h2,
.about-copy h2,
.credentials h2 {
  color: var(--navy);
  font-family: "Playfair Display", serif;
  font-size: 42px;
  font-weight: 500;
  line-height: 1.2;
  margin-top: 10px;
}

.section-heading p {
  color: var(--muted);
  margin: 14px auto 0;
  max-width: 650px;
}

/* Hero */

.hero {
  min-height: 570px;
  background:
    linear-gradient(90deg, rgba(17, 43, 70, 0.96), rgba(17, 43, 70, 0.86)),
    url("https://images.unsplash.com/photo-1485827404703-89b55fcc595e?auto=format&fit=crop&w=1800&q=85")
    center / cover;
  color: white;
}

.hero-layout {
  min-height: 570px;
  display: grid;
  grid-template-columns: 1.25fr 0.75fr;
  align-items: center;
  gap: 70px;
}

.hero-content {
  max-width: 720px;
  padding: 90px 0;
}

.hero h1 {
  max-width: 800px;
  font-family: "Playfair Display", serif;
  font-size: clamp(42px, 6vw, 74px);
  font-weight: 500;
  line-height: 1.1;
  margin: 18px 0;
}

.hero p {
  color: #e7edf1;
  font-size: 17px;
  max-width: 620px;
}

.button {
  display: inline-block;
  border: 1px solid var(--gold);
  color: white;
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 1px;
  margin-top: 30px;
  padding: 13px 23px;
  text-transform: uppercase;
  transition: background 0.2s ease, color 0.2s ease;
}

.button:hover,
.button:focus {
  background: var(--gold);
  color: white;
}

.hero-photo {
  align-self: stretch;
  display: flex;
  align-items: flex-end;
  justify-content: center;
  padding-top: 45px;
}

.hero-photo img {
  width: min(100%, 390px);
  height: 480px;
  object-fit: cover;
  object-position: center top;
  border: 8px solid rgba(255, 255, 255, 0.9);
  box-shadow: 0 15px 40px rgba(0, 0, 0, 0.25);
}

/* About */

.about {
  display: grid;
  grid-template-columns: 0.85fr 1.15fr;
  align-items: center;
  gap: 75px;
}

.about-placeholder {
  min-height: 460px;
  display: flex;
  flex-direction: column;
  justify-content: center;
  background: var(--light-blue);
  padding: 55px;
}

.about-placeholder h2 {
  color: var(--navy);
  font-family: "Playfair Display", serif;
  font-size: 36px;
  font-weight: 500;
  line-height: 1.25;
  margin-top: 18px;
}

.about-copy h2 {
  font-size: 32px;
  margin-bottom: 18px;
}

.about-copy p + p {
  margin-top: 17px;
}

.signature {
  color: var(--navy);
  font-family: "Playfair Display", serif;
  font-size: 25px;
  margin-top: 25px;
}

/* Research */

.research {
  background: var(--light-blue);
}

.research-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 22px;
}

.research-card {
  min-height: 190px;
  border: 1px solid #d6e4ec;
  background: white;
  padding: 30px;
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.research-card:hover {
  box-shadow: 0 10px 30px rgba(17, 43, 70, 0.1);
  transform: translateY(-5px);
}

.research-number {
  color: var(--gold);
  font-size: 13px;
  font-weight: 700;
}

.research-card h3 {
  color: var(--navy);
  font-size: 17px;
  line-height: 1.4;
  margin: 17px 0 10px;
}

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

/* Education and publications */

.credentials {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 70px;
}

.credentials h2 {
  font-size: 30px;
  margin-bottom: 25px;
}

.timeline-item {
  border-left: 2px solid var(--gold);
  margin-bottom: 25px;
  padding-left: 22px;
}

.timeline-item strong {
  color: var(--navy);
  display: block;
  font-size: 15px;
}

.timeline-item span {
  color: var(--gold);
  display: block;
  font-size: 12px;
  font-weight: 700;
  margin: 4px 0;
}

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

.publication {
  border-bottom: 1px solid var(--border);
  padding: 24px 0;
}

.publication:first-of-type {
  border-top: 1px solid var(--border);
}

.publication h3 {
  color: var(--navy);
  font-size: 16px;
  line-height: 1.5;
}

.publication p {
  color: var(--muted);
  font-size: 13px;
  margin-top: 7px;
}

/* Contact */

.contact {
  background: var(--navy);
  color: white;
}

.contact-grid {
  display: grid;
  grid-template-columns: 0.8fr 1.2fr;
  gap: 80px;
}

.contact-heading {
  text-align: left;
}

.contact .section-heading h2 {
  color: white;
}

.contact .section-heading p {
  color: #c5d1da;
  margin-left: 0;
}

.contact-details {
  color: #d5e0e6;
  font-size: 14px;
}

.contact-details div {
  border-bottom: 1px solid rgba(255, 255, 255, 0.18);
  padding: 14px 0;
}

.contact-details strong {
  color: var(--gold);
  display: block;
  font-size: 11px;
  letter-spacing: 1px;
  text-transform: uppercase;
}

.contact-details a:hover {
  color: var(--gold);
}

form {
  display: grid;
  gap: 15px;
}

input,
textarea {
  width: 100%;
  border: 1px solid rgba(255, 255, 255, 0.3);
  background: rgba(255, 255, 255, 0.08);
  color: white;
  outline: none;
  padding: 14px 16px;
}

input:focus,
textarea:focus {
  border-color: var(--gold);
}

input::placeholder,
textarea::placeholder {
  color: #c4d0d9;
}

textarea {
  min-height: 145px;
  resize: vertical;
}

form .button {
  width: fit-content;
  background: transparent;
  cursor: pointer;
}

.form-message {
  color: #d5e0e6;
  font-size: 13px;
}

/* Footer */

footer {
  background: #0b2034;
  color: #b8c5ce;
  font-size: 12px;
  padding: 24px 0;
  text-align: center;
}

/* Tablet */

@media (max-width: 800px) {
  .nav-links {
    display: none;
    position: absolute;
    top: 80px;
    left: 0;
    right: 0;
    background: white;
    flex-direction: column;
    gap: 0;
    padding: 8px 20px 18px;
  }

  .nav-links.open {
    display: flex;
  }

  .nav-links li {
    border-bottom: 1px solid var(--border);
    padding: 13px 0;
  }

  .menu-button {
    display: block;
  }

  .hero-layout {
    min-height: auto;
    grid-template-columns: 1fr;
    gap: 20px;
    padding: 60px 0;
  }

  .hero-content {
    order: 1;
    padding: 20px 0 0;
  }

  .hero-photo {
    order: 2;
    padding-top: 0;
  }

  .hero-photo img {
    width: min(100%, 300px);
    height: 360px;
  }

  .about,
  .credentials,
  .contact-grid {
    grid-template-columns: 1fr;
    gap: 40px;
  }

  .research-grid {
    grid-template-columns: 1fr 1fr;
  }
}

/* Mobile */

@media (max-width: 520px) {
  .container {
    width: min(100% - 28px, var(--max-width));
  }

  section {
    padding: 65px 0;
  }

  .topbar-content {
    display: block;
    text-align: center;
  }

  .topbar-content span:last-child {
    display: none;
  }

  .hero h1 {
    font-size: 43px;
  }

  .research-grid {
    grid-template-columns: 1fr;
  }

  .about-placeholder {
    min-height: 300px;
    padding: 35px;
  }

  .about-placeholder h2 {
    font-size: 30px;
  }
}