:root {
  --color-bg: #f7f2e8;
  --color-bg-soft: #fbf7ef;
  --color-surface: #fffaf0;
  --color-surface-strong: #ffffff;
  --color-text: #1f2933;
  --color-muted: #667085;
  --color-border: #ded6c7;
  --color-border-strong: #c9bda9;
  --color-primary: #17324d;
  --color-primary-light: #244d73;
  --color-primary-dark: #102338;
  --color-accent: #a66a2c;
  --color-accent-soft: #ead8bf;

  --font-body: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  --font-heading: Georgia, "Times New Roman", serif;

  --container: 1120px;
  --radius-sm: 10px;
  --radius-md: 16px;
  --radius-lg: 24px;

  --shadow-sm: 0 8px 20px rgba(16, 35, 56, 0.07);
  --shadow-md: 0 18px 50px rgba(16, 35, 56, 0.12);

  --transition: 180ms ease;
}

/* Base */

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

html {
  color-scheme: light;
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.6;
  color: var(--color-text);
  background:
    radial-gradient(circle at top left, rgba(166, 106, 44, 0.08), transparent 34rem),
    var(--color-bg);
}

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

a {
  color: inherit;
  text-decoration-color: rgba(166, 106, 44, 0.45);
  text-underline-offset: 0.18em;
}

a:hover {
  color: var(--color-primary-light);
  text-decoration-color: currentColor;
}

button,
input {
  font: inherit;
}

h1,
h2,
h3 {
  margin: 0;
  font-family: var(--font-heading);
  line-height: 1.12;
  color: var(--color-primary-dark);
}

p {
  margin: 0;
}

ul {
  margin: 0;
  padding: 0;
}

.container {
  width: min(var(--container), calc(100% - 32px));
  margin-inline: auto;
}

.section {
  padding-block: clamp(3.5rem, 7vw, 6rem);
}

.section-header {
  max-width: 740px;
  margin-bottom: 2rem;
}

.section-header h1,
.section-header h2 {
  font-size: clamp(2rem, 4vw, 3rem);
  margin-top: 0.3rem;
}

.section-header p {
  margin-top: 0.85rem;
  color: var(--color-muted);
  font-size: 1.05rem;
}

.section-header-split {
  max-width: none;
  display: flex;
  justify-content: space-between;
  align-items: end;
  gap: 1.5rem;
}

.eyebrow {
  color: var(--color-accent);
  font-size: 0.76rem;
  font-weight: 800;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

.sr-only,
.skip-link:not(:focus) {
  position: absolute;
  width: 1px;
  height: 1px;
  clip-path: inset(50%);
  overflow: hidden;
  white-space: nowrap;
}

.skip-link:focus {
  position: fixed;
  z-index: 999;
  top: 1rem;
  left: 1rem;
  padding: 0.75rem 1rem;
  color: #fff;
  background: var(--color-primary);
  border-radius: var(--radius-sm);
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: 0.72rem 1rem;
  border: 1px solid transparent;
  border-radius: 999px;
  font-weight: 800;
  text-decoration: none;
  transition:
    background-color var(--transition),
    border-color var(--transition),
    color var(--transition),
    transform var(--transition);
}

.button:hover {
  transform: translateY(-1px);
}

.button-primary {
  color: #fff;
  background: var(--color-primary);
  border-color: var(--color-primary);
}

.button-primary:hover {
  color: #fff;
  background: var(--color-primary-light);
  border-color: var(--color-primary-light);
}

.button-secondary {
  color: var(--color-primary-dark);
  background: var(--color-accent-soft);
  border-color: rgba(166, 106, 44, 0.18);
}

.button-secondary:hover {
  color: var(--color-primary-dark);
  background: #efd2a9;
}

.button-ghost {
  color: var(--color-primary-dark);
  background: rgba(255, 255, 255, 0.72);
  border-color: rgba(255, 255, 255, 0.7);
}

.button-ghost:hover {
  background: #fff;
}

.section-link,
.text-link {
  font-weight: 800;
  color: var(--color-primary);
}

.section-link {
  white-space: nowrap;
}

/* Header */

.site-header {
  position: sticky;
  z-index: 100;
  top: 0;
  background: rgba(247, 242, 232, 0.9);
  border-bottom: 1px solid rgba(222, 214, 199, 0.75);
  backdrop-filter: blur(16px);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: 76px;
  gap: 1.5rem;
}

.site-brand {
  display: inline-flex;
  align-items: center;
  gap: 0.75rem;
  color: var(--color-primary-dark);
  text-decoration: none;
}

.site-logo {
  width: 48px;
  height: 48px;
  object-fit: contain;
}

.site-brand strong {
  display: block;
  font-family: var(--font-heading);
  font-size: 1.28rem;
  line-height: 1.1;
}

.site-brand small {
  display: block;
  color: var(--color-muted);
  font-size: 0.78rem;
  line-height: 1.2;
}

.site-nav ul {
  display: flex;
  align-items: center;
  gap: 0.2rem;
  list-style: none;
}

.site-nav a {
  display: inline-flex;
  padding: 0.6rem 0.72rem;
  border-radius: 999px;
  color: var(--color-primary-dark);
  font-size: 0.93rem;
  font-weight: 750;
  text-decoration: none;
}

.site-nav a:hover,
.site-nav a[aria-current="page"] {
  background: rgba(23, 50, 77, 0.08);
}

.nav-toggle-button {
  display: none;
}

/* Hero */

.hero-section {
  position: relative;
  isolation: isolate;
  min-height: 660px;
  display: grid;
  align-items: center;
  overflow: hidden;
  color: #fff;
  background: var(--color-primary-dark);
}

.hero-media {
  position: absolute;
  inset: 0;
  z-index: -2;
  background:
    linear-gradient(90deg, rgba(16, 35, 56, 0.93), rgba(16, 35, 56, 0.72), rgba(16, 35, 56, 0.35)),
    var(--hero-image, url("/assets/images/hero-aviation.jpg")) center / cover no-repeat;
}

.hero-section::after {
  content: "";
  position: absolute;
  inset: auto 0 0;
  z-index: -1;
  height: 40%;
  background: linear-gradient(transparent, rgba(16, 35, 56, 0.75));
}

.hero-content {
  max-width: 760px;
  padding-block: 5rem;
}

.hero-content .eyebrow {
  color: #efc27e;
}

.hero-content h1 {
  margin-top: 0.55rem;
  color: #fffaf0;
  font-size: clamp(2.5rem, 7vw, 5.65rem);
  letter-spacing: -0.045em;
}

.hero-lead {
  max-width: 680px;
  margin-top: 1.35rem;
  color: rgba(255, 250, 240, 0.88);
  font-size: clamp(1.05rem, 2vw, 1.28rem);
}

.hero-search {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 0.55rem;
  max-width: 760px;
  margin-top: 2rem;
  padding: 0.45rem;
  background: rgba(255, 250, 240, 0.96);
  border: 1px solid rgba(255, 255, 255, 0.45);
  border-radius: 999px;
  box-shadow: var(--shadow-md);
}

.hero-search input {
  min-width: 0;
  width: 100%;
  padding: 0.9rem 1rem;
  color: var(--color-text);
  background: transparent;
  border: 0;
  outline: 0;
}

.hero-search input::placeholder {
  color: #7b8794;
}

.hero-search button {
  min-height: 48px;
  padding-inline: 1.35rem;
  color: #fff;
  font-weight: 800;
  background: var(--color-accent);
  border: 0;
  border-radius: 999px;
  cursor: pointer;
  transition: background-color var(--transition);
}

.hero-search button:hover {
  background: #8d5621;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-top: 1.25rem;
}

/* Feature grid */

.section-archive {
  background: linear-gradient(180deg, var(--color-bg), var(--color-bg-soft));
}

.feature-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.15rem;
}

.feature-card {
  position: relative;
  min-height: 235px;
  padding: 1.35rem;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-sm);
  transition:
    transform var(--transition),
    border-color var(--transition),
    box-shadow var(--transition);
}

.feature-card:hover {
  transform: translateY(-3px);
  border-color: var(--color-border-strong);
  box-shadow: var(--shadow-md);
}

.card-icon {
  display: grid;
  place-items: center;
  width: 42px;
  height: 42px;
  margin-bottom: 1.1rem;
  color: var(--color-primary);
  background: var(--color-accent-soft);
  border-radius: 50%;
  font-weight: 900;
}

.feature-card h3 {
  font-size: 1.45rem;
}

.feature-card h3 a {
  text-decoration: none;
}

.feature-card h3 a::after {
  content: "";
  position: absolute;
  inset: 0;
}

.feature-card p {
  margin-top: 0.8rem;
  color: var(--color-muted);
}

/* Archive highlight */

.section-highlight {
  background: var(--color-bg-soft);
}

.archive-highlight {
  display: grid;
  grid-template-columns: minmax(0, 1.15fr) minmax(320px, 0.85fr);
  gap: 1.25rem;
  align-items: stretch;
}

.archive-photo-card {
  overflow: hidden;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-sm);
}

.archive-photo-card a {
  display: block;
  height: 100%;
  color: inherit;
  text-decoration: none;
}

.archive-photo-card figure {
  height: 100%;
  margin: 0;
}

.archive-photo-card img {
  width: 100%;
  height: 420px;
  object-fit: cover;
  filter: sepia(0.2) contrast(0.96);
}

.archive-photo-card figcaption {
  padding: 1.2rem;
  color: var(--color-muted);
}

.archive-photo-card figcaption span {
  display: block;
  margin-bottom: 0.2rem;
  color: var(--color-accent);
  font-size: 0.76rem;
  font-weight: 800;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

.archive-list {
  display: grid;
  gap: 1rem;
}

.small-feature {
  padding: 1.2rem;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-sm);
}

.small-feature h3 {
  margin-top: 0.25rem;
  font-size: 1.35rem;
}

.small-feature h3 a {
  text-decoration: none;
}

.small-feature p:not(.eyebrow) {
  margin-top: 0.65rem;
  color: var(--color-muted);
}

/* Topics */

.section-topics {
  background:
    linear-gradient(rgba(23, 50, 77, 0.035), rgba(23, 50, 77, 0.035)),
    var(--color-bg);
}

.topic-list {
  display: flex;
  flex-wrap: wrap;
  gap: 0.7rem;
}

.topic-list a {
  display: inline-flex;
  align-items: center;
  min-height: 42px;
  padding: 0.55rem 0.9rem;
  color: var(--color-primary-dark);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: 999px;
  font-weight: 750;
  text-decoration: none;
  box-shadow: 0 3px 10px rgba(16, 35, 56, 0.04);
  transition:
    background-color var(--transition),
    border-color var(--transition),
    transform var(--transition);
}

.topic-list a:hover {
  transform: translateY(-1px);
  background: #fff;
  border-color: var(--color-border-strong);
}

/* Publications */

.section-publications {
  background: var(--color-bg-soft);
}

.publication-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1.25rem;
}

.publication-card {
  display: grid;
  grid-template-columns: 150px 1fr;
  gap: 1rem;
  padding: 1rem;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-sm);
}

.publication-card img {
  width: 100%;
  height: 205px;
  object-fit: cover;
  background: var(--color-accent-soft);
  border-radius: var(--radius-md);
  filter: sepia(0.12);
}

.publication-card h3 {
  margin-top: 0.2rem;
  font-size: 1.45rem;
}

.publication-card h3 a {
  text-decoration: none;
}

.publication-card p:not(.eyebrow) {
  margin-top: 0.65rem;
  color: var(--color-muted);
}

.publication-card .text-link {
  display: inline-flex;
  margin-top: 0.9rem;
}

/* Contribute */

.section-contribute {
  background: var(--color-bg);
}

.contribute-box {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 2rem;
  align-items: center;
  padding: clamp(1.4rem, 4vw, 2.2rem);
  color: #fff;
  background:
    radial-gradient(circle at top right, rgba(239, 194, 126, 0.2), transparent 22rem),
    var(--color-primary);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-md);
}

.contribute-box .eyebrow {
  color: #efc27e;
}

.contribute-box h2 {
  margin-top: 0.3rem;
  color: #fffaf0;
  font-size: clamp(1.8rem, 4vw, 3rem);
}

.contribute-box p:not(.eyebrow) {
  max-width: 720px;
  margin-top: 0.8rem;
  color: rgba(255, 250, 240, 0.82);
}

.contribute-actions {
  display: flex;
  flex-wrap: wrap;
  justify-content: end;
  gap: 0.75rem;
}

.contribute-box .button-secondary {
  color: #fffaf0;
  background: rgba(255, 250, 240, 0.12);
  border-color: rgba(255, 250, 240, 0.22);
}

.contribute-box .button-secondary:hover {
  background: rgba(255, 250, 240, 0.18);
}

/* Placeholder pages */

.placeholder-page {
  min-height: 55vh;
}

/* Footer */

.site-footer {
  color: rgba(255, 250, 240, 0.78);
  background: var(--color-primary-dark);
}

.footer-grid {
  display: grid;
  grid-template-columns: 1.5fr repeat(3, 1fr);
  gap: 2rem;
  padding-block: 3rem;
}

.footer-brand {
  display: inline-flex;
  align-items: center;
  gap: 0.7rem;
  color: #fffaf0;
  font-family: var(--font-heading);
  font-size: 1.25rem;
  font-weight: 700;
  text-decoration: none;
}

.footer-logo {
  width: 42px;
  height: 42px;
  object-fit: contain;
}

.site-footer p {
  margin-top: 1rem;
  max-width: 360px;
}

.site-footer h2 {
  color: #fffaf0;
  font-family: var(--font-body);
  font-size: 0.85rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.site-footer ul {
  margin-top: 0.9rem;
  list-style: none;
}

.site-footer li + li {
  margin-top: 0.45rem;
}

.site-footer a {
  color: rgba(255, 250, 240, 0.82);
  text-decoration: none;
}

.site-footer a:hover {
  color: #fffaf0;
  text-decoration: underline;
  text-underline-offset: 0.2em;
}

.footer-bottom {
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  padding-block: 1.2rem;
  border-top: 1px solid rgba(255, 250, 240, 0.14);
}

.footer-bottom p {
  margin: 0;
  max-width: none;
  font-size: 0.9rem;
}

/* Responsive */

@media (max-width: 980px) {
  .site-nav {
    position: fixed;
    top: 76px;
    right: 16px;
    left: 16px;
    display: none;
    padding: 1rem;
    background: rgba(255, 250, 240, 0.98);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
  }

  .site-nav.is-open {
    display: block;
  }

  .site-nav ul {
    display: grid;
    gap: 0.2rem;
  }

  .site-nav a {
    display: flex;
    padding: 0.85rem 1rem;
  }

  .nav-toggle-button {
    display: grid;
    gap: 5px;
    width: 44px;
    height: 44px;
    place-content: center;
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: 999px;
    cursor: pointer;
  }

  .nav-toggle-button span:not(.sr-only) {
    display: block;
    width: 20px;
    height: 2px;
    background: var(--color-primary-dark);
    border-radius: 99px;
  }

  .feature-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .archive-highlight {
    grid-template-columns: 1fr;
  }

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

  .contribute-box {
    grid-template-columns: 1fr;
  }

  .contribute-actions {
    justify-content: start;
  }

  .footer-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 720px) {
  .container {
    width: min(var(--container), calc(100% - 24px));
  }

  .site-logo {
    width: 42px;
    height: 42px;
  }

  .site-brand small {
    display: none;
  }

  .hero-section {
    min-height: auto;
  }

  .hero-media {
    background:
      linear-gradient(180deg, rgba(16, 35, 56, 0.94), rgba(16, 35, 56, 0.78)),
      var(--hero-image, url("/assets/images/hero-aviation.jpg")) center / cover no-repeat;
  }

  .hero-content {
    padding-block: 4.5rem;
  }

  .hero-search {
    grid-template-columns: 1fr;
    border-radius: var(--radius-lg);
  }

  .hero-search input {
    padding: 0.9rem 1rem 0.4rem;
  }

  .hero-search button {
    width: 100%;
  }

  .hero-actions {
    display: grid;
  }

  .button {
    width: 100%;
  }

  .section-header-split {
    display: block;
  }

  .section-link {
    display: inline-flex;
    margin-top: 1rem;
  }

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

  .feature-card {
    min-height: auto;
  }

  .archive-photo-card img {
    height: 280px;
  }

  .publication-card {
    grid-template-columns: 1fr;
  }

  .publication-card img {
    height: 240px;
  }

  .topic-list {
    gap: 0.55rem;
  }

  .topic-list a {
    width: 100%;
    justify-content: center;
  }

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

  .footer-bottom {
    display: block;
  }

  .footer-bottom p + p {
    margin-top: 0.45rem;
  }
}

@media (max-width: 430px) {
  .header-inner {
    min-height: 68px;
  }

  .site-nav {
    top: 68px;
  }

  .site-brand strong {
    font-size: 1.1rem;
  }

  .hero-content h1 {
    font-size: 2.35rem;
  }

  .section {
    padding-block: 3rem;
  }
}