/* IMARENS — Institute for Marine and Environmental Sciences Nigeria */

:root {
  --ocean-deep: #0a3d62;
  --ocean-mid: #1e6b8a;
  --ocean-light: #3a9bc2;
  --teal: #2a9d8f;
  --teal-light: #48c9b0;
  --sand: #f4f7f9;
  --white: #ffffff;
  --text: #1a2b3c;
  --text-muted: #5a6b7c;
  --border: #dde4ea;
  --shadow: 0 4px 24px rgba(10, 61, 98, 0.12);
  --radius: 8px;
  --max-width: 1200px;
  --header-height: 76px;
  --nav-dropdown-bg: #ffffff;
  --nav-dropdown-shadow: 0 12px 40px rgba(10, 61, 98, 0.14);
  --font-sans: "Segoe UI", system-ui, -apple-system, sans-serif;
  --font-serif: Georgia, "Times New Roman", serif;
}

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

html { scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: var(--font-sans);
  color: var(--text);
  line-height: 1.65;
  background: var(--white);
}

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

a { color: var(--ocean-mid); text-decoration: none; transition: color 0.2s; }
a:hover { color: var(--teal); }

.container {
  width: min(100% - 2rem, var(--max-width));
  margin-inline: auto;
}

/* Header */
.site-header {
  position: sticky;
  top: 0;
  z-index: 200;
  background: rgba(255, 255, 255, 0.92);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid transparent;
  transition: border-color 0.25s, box-shadow 0.25s;
  overflow: visible;
}

.site-header.is-scrolled {
  border-bottom-color: var(--border);
  box-shadow: 0 4px 24px rgba(10, 61, 98, 0.08);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: var(--header-height);
  gap: 2rem;
  overflow: visible;
  position: relative;
}

.logo {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  color: var(--ocean-deep);
  font-weight: 700;
  font-size: 1.1rem;
  line-height: 1.2;
  flex-shrink: 0;
  text-decoration: none;
}

.logo:hover { color: var(--ocean-deep); }

.logo-img {
  height: 42px;
  width: auto;
  max-width: 148px;
  object-fit: contain;
  flex-shrink: 0;
  display: block;
}

.logo-text span {
  display: block;
  font-size: 0.68rem;
  font-weight: 500;
  color: var(--text-muted);
  letter-spacing: 0.02em;
}

/* Nav toggle (hamburger) */
.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 44px;
  height: 44px;
  background: var(--sand);
  border: 1px solid var(--border);
  border-radius: 10px;
  cursor: pointer;
  padding: 0;
  z-index: 210;
  transition: background 0.2s;
}

.nav-toggle:hover { background: var(--border); }

.nav-toggle-bar {
  display: block;
  width: 20px;
  height: 2px;
  background: var(--ocean-deep);
  border-radius: 2px;
  margin: 0 auto;
  transition: transform 0.3s, opacity 0.3s;
}

.nav-toggle[aria-expanded="true"] .nav-toggle-bar:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}

.nav-toggle[aria-expanded="true"] .nav-toggle-bar:nth-child(2) { opacity: 0; }

.nav-toggle[aria-expanded="true"] .nav-toggle-bar:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

/* Main navigation */
.main-nav { flex: 1; display: flex; justify-content: flex-end; overflow: visible; }

.nav-list {
  display: flex;
  align-items: center;
  gap: 0.15rem;
  list-style: none;
  margin: 0;
  padding: 0;
}

.nav-list > li { position: relative; }

/* Invisible bridge so cursor can reach the panel without closing */
.nav-dropdown::after {
  content: "";
  position: absolute;
  top: 100%;
  left: 0;
  right: 0;
  height: 14px;
  display: none;
}

.nav-dropdown.is-open::after,
.nav-dropdown:focus-within::after {
  display: block;
}

.nav-list > li > a,
.nav-dropdown-trigger {
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--text);
  padding: 0.5rem 0.85rem;
  border-radius: 8px;
  border: none;
  background: none;
  cursor: pointer;
  font-family: inherit;
  white-space: nowrap;
  transition: color 0.2s, background 0.2s;
  text-decoration: none;
}

.nav-list > li > a:hover,
.nav-dropdown-trigger:hover,
.nav-dropdown.is-open > .nav-dropdown-trigger {
  color: var(--ocean-mid);
  background: rgba(42, 157, 143, 0.08);
}

.nav-list > li > a.active,
.nav-dropdown.is-active > .nav-dropdown-trigger {
  color: var(--ocean-deep);
  background: rgba(30, 107, 138, 0.1);
  font-weight: 600;
}

.nav-chevron {
  width: 14px;
  height: 14px;
  opacity: 0.55;
  transition: transform 0.25s;
  flex-shrink: 0;
}

.nav-dropdown.is-open .nav-chevron { transform: rotate(180deg); }

/* Dropdown panel */
.nav-dropdown-menu {
  position: absolute;
  top: calc(100% + 10px);
  left: 50%;
  transform: translateX(-50%) translateY(4px);
  min-width: 260px;
  background: var(--nav-dropdown-bg);
  border: 1px solid var(--border);
  border-radius: 12px;
  box-shadow: var(--nav-dropdown-shadow);
  list-style: none;
  margin: 0;
  padding: 0.5rem;
  opacity: 0;
  visibility: hidden;
  pointer-events: none;
  transition: opacity 0.2s, transform 0.2s, visibility 0.2s;
  z-index: 400;
}

.nav-dropdown-menu::before {
  content: "";
  position: absolute;
  top: -6px;
  left: 50%;
  transform: translateX(-50%) rotate(45deg);
  width: 10px;
  height: 10px;
  background: var(--nav-dropdown-bg);
  border-left: 1px solid var(--border);
  border-top: 1px solid var(--border);
  pointer-events: none;
}

.nav-dropdown.is-open .nav-dropdown-menu,
.nav-dropdown:focus-within .nav-dropdown-menu {
  opacity: 1;
  visibility: visible;
  pointer-events: auto;
  transform: translateX(-50%) translateY(0);
}

@media (min-width: 901px) {
  .nav-dropdown:hover .nav-dropdown-menu {
    opacity: 1;
    visibility: visible;
    pointer-events: auto;
    transform: translateX(-50%) translateY(0);
  }

  .nav-dropdown:hover::after {
    display: block;
  }
}

.nav-dropdown-menu a {
  display: block;
  padding: 0.65rem 1rem;
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--text);
  border-radius: 8px;
  transition: background 0.15s, color 0.15s;
  position: relative;
  z-index: 1;
}

.nav-dropdown-menu a:hover {
  background: var(--sand);
  color: var(--ocean-mid);
}

.nav-dropdown-menu a.active {
  background: rgba(42, 157, 143, 0.12);
  color: var(--ocean-deep);
  font-weight: 600;
}

.nav-dropdown-menu a .nav-item-desc {
  display: block;
  font-size: 0.75rem;
  font-weight: 400;
  color: var(--text-muted);
  margin-top: 0.15rem;
}

/* Contact CTA in nav */
.nav-cta {
  background: linear-gradient(135deg, var(--ocean-mid), var(--teal)) !important;
  color: var(--white) !important;
  padding: 0.55rem 1.25rem !important;
  border-radius: 8px !important;
  font-weight: 600 !important;
  box-shadow: 0 4px 14px rgba(42, 157, 143, 0.35);
  margin-left: 0.35rem;
}

.nav-cta:hover {
  background: linear-gradient(135deg, var(--ocean-light), var(--teal-light)) !important;
  color: var(--white) !important;
  transform: translateY(-1px);
  box-shadow: 0 6px 18px rgba(42, 157, 143, 0.4);
}

.nav-cta.active {
  background: linear-gradient(135deg, var(--ocean-deep), var(--ocean-mid)) !important;
  color: var(--white) !important;
}

/* Mobile nav overlay */
.nav-backdrop {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(10, 61, 98, 0.4);
  z-index: 190;
  opacity: 0;
  transition: opacity 0.3s;
}

.nav-backdrop.is-visible {
  display: block;
  opacity: 1;
}

/* Hero */
.hero {
  position: relative;
  min-height: 520px;
  display: flex;
  align-items: center;
  color: var(--white);
  overflow: hidden;
}

.hero-bg {
  position: absolute;
  inset: 0;
  background-size: cover;
  background-position: center;
  z-index: 0;
}

.hero-bg::after {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, rgba(10,61,98,0.88) 0%, rgba(30,107,138,0.72) 60%, rgba(42,157,143,0.55) 100%);
}

.hero .container { position: relative; z-index: 1; padding-block: 4rem; }

.hero h1.hero-label {
  display: block;
  font-size: clamp(2rem, 5.5vw, 3.5rem);
  font-weight: 700;
  letter-spacing: 0.01em;
  color: var(--white);
  margin: 0 0 1.25rem;
  max-width: 820px;
  line-height: 1.2;
}

.hero-tagline {
  font-size: clamp(1.2rem, 2.8vw, 1.65rem);
  font-weight: 500;
  line-height: 1.4;
  margin: 0 0 1.25rem;
  max-width: 720px;
  opacity: 0.95;
  color: var(--white);
}

.hero-sub {
  font-size: clamp(1rem, 2vw, 1.25rem);
  opacity: 0.92;
  max-width: 600px;
  margin: 0 0 2rem;
}

.btn {
  display: inline-block;
  padding: 0.75rem 1.75rem;
  border-radius: var(--radius);
  font-weight: 600;
  font-size: 0.95rem;
  cursor: pointer;
  border: 2px solid transparent;
  transition: all 0.2s;
}

.btn-primary {
  background: var(--teal);
  color: var(--white);
  border-color: var(--teal);
}

.btn-primary:hover {
  background: var(--teal-light);
  border-color: var(--teal-light);
  color: var(--white);
}

.btn-outline {
  background: transparent;
  color: var(--white);
  border-color: rgba(255,255,255,0.7);
  margin-left: 0.75rem;
}

.btn-outline:hover {
  background: rgba(255,255,255,0.15);
  color: var(--white);
}

.btn-dark {
  background: var(--ocean-deep);
  color: var(--white);
  border-color: var(--ocean-deep);
}

.btn-dark:hover {
  background: var(--ocean-mid);
  border-color: var(--ocean-mid);
  color: var(--white);
}

/* Sections */
section { padding: 4.5rem 0; }

.section-alt { background: var(--sand); }

.section-header {
  text-align: center;
  max-width: 680px;
  margin: 0 auto 3rem;
}

.section-header h2 {
  font-size: clamp(1.75rem, 3vw, 2.25rem);
  color: var(--ocean-deep);
  margin: 0 0 0.75rem;
}

.section-header p {
  color: var(--text-muted);
  margin: 0;
  font-size: 1.05rem;
}

.section-label {
  display: inline-block;
  font-size: 0.8rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--teal);
  margin-bottom: 0.5rem;
}

/* Page hero (inner pages) */
.page-hero {
  background: linear-gradient(135deg, var(--ocean-deep), var(--ocean-mid));
  color: var(--white);
  padding: 3.5rem 0;
  text-align: center;
}

.page-hero h1 {
  margin: 0 0 0.5rem;
  font-size: clamp(1.75rem, 4vw, 2.5rem);
}

.page-hero p {
  margin: 0;
  opacity: 0.88;
  font-size: 1.1rem;
}

/* Two column layout */
.split {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 3rem;
  align-items: center;
}

.split img {
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  width: 100%;
  object-fit: cover;
  aspect-ratio: 4/3;
}

.split h2 {
  color: var(--ocean-deep);
  font-size: 1.75rem;
  margin: 0 0 1rem;
}

.split p { color: var(--text-muted); margin: 0 0 1rem; }

/* Mission / Vision cards */
.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1.5rem;
}

.card {
  background: var(--white);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 2rem;
  box-shadow: var(--shadow);
}

.card h3 {
  color: var(--ocean-deep);
  margin: 0 0 0.75rem;
  font-size: 1.2rem;
}

.card p { margin: 0; color: var(--text-muted); }

.card-icon {
  width: 48px;
  height: 48px;
  background: linear-gradient(135deg, var(--ocean-light), var(--teal));
  border-radius: var(--radius);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.4rem;
  margin-bottom: 1rem;
}

/* Research areas */
.research-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 1.5rem;
}

.research-card {
  background: var(--white);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.75rem;
  transition: box-shadow 0.2s, transform 0.2s;
}

.research-card:hover {
  box-shadow: var(--shadow);
  transform: translateY(-2px);
}

.research-card h3 {
  color: var(--ocean-deep);
  margin: 0 0 0.5rem;
  font-size: 1.1rem;
}

.research-card .num {
  display: inline-block;
  background: var(--sand);
  color: var(--ocean-mid);
  font-weight: 700;
  font-size: 0.8rem;
  padding: 0.2rem 0.6rem;
  border-radius: 4px;
  margin-bottom: 0.75rem;
}

.research-card ul {
  margin: 0.75rem 0 0;
  padding-left: 1.2rem;
  color: var(--text-muted);
  font-size: 0.9rem;
}

.research-card li { margin-bottom: 0.25rem; }

/* News cards */
.news-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 2rem;
}

.news-card {
  background: var(--white);
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: var(--shadow);
  border: 1px solid var(--border);
  display: flex;
  flex-direction: column;
}

.news-card img {
  width: 100%;
  aspect-ratio: 16/10;
  object-fit: cover;
}

.news-card-body {
  padding: 1.5rem;
  flex: 1;
  display: flex;
  flex-direction: column;
}

.news-card h3 {
  color: var(--ocean-deep);
  margin: 0 0 0.75rem;
  font-size: 1.05rem;
  line-height: 1.4;
}

.news-card p {
  color: var(--text-muted);
  font-size: 0.92rem;
  margin: 0 0 1rem;
  flex: 1;
}

.news-card .news-links a {
  display: inline-block;
  font-size: 0.85rem;
  margin-right: 1rem;
}

.news-date {
  font-size: 0.8rem;
  color: var(--teal);
  font-weight: 600;
  margin-bottom: 0.5rem;
}

/* Contact */
.contact-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 3rem;
}

.contact-info h3 {
  color: var(--ocean-deep);
  margin: 0 0 1rem;
}

.contact-item {
  display: flex;
  gap: 1rem;
  margin-bottom: 1.25rem;
}

.contact-item-icon {
  width: 40px;
  height: 40px;
  background: var(--sand);
  border-radius: var(--radius);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.1rem;
  flex-shrink: 0;
}

.contact-item strong { display: block; color: var(--ocean-deep); font-size: 0.9rem; }
.contact-item span, .contact-item a { font-size: 0.92rem; color: var(--text-muted); }

.contact-form {
  background: var(--sand);
  padding: 2rem;
  border-radius: var(--radius);
}

.form-group { margin-bottom: 1.25rem; }

.form-group label {
  display: block;
  font-weight: 600;
  font-size: 0.875rem;
  margin-bottom: 0.4rem;
  color: var(--ocean-deep);
}

.form-group input,
.form-group textarea,
.form-group select {
  width: 100%;
  padding: 0.7rem 1rem;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  font-family: inherit;
  font-size: 0.95rem;
  background: var(--white);
}

.form-group textarea { min-height: 120px; resize: vertical; }

.form-alert {
  padding: 0.85rem 1rem;
  border-radius: var(--radius);
  font-size: 0.9rem;
  margin-bottom: 1.25rem;
  line-height: 1.5;
}

.form-alert--success {
  background: #e8f8f2;
  color: #1a6b4f;
  border: 1px solid #9ddfc4;
}

.form-alert--error {
  background: #fef2f2;
  color: #9b2c2c;
  border: 1px solid #f5c6c6;
}

button[type="submit"]:disabled {
  opacity: 0.65;
  cursor: not-allowed;
}

/* Content page prose */
.prose { max-width: 760px; }
.prose h2 { color: var(--ocean-deep); margin: 2rem 0 0.75rem; }
.prose h3 { color: var(--ocean-mid); margin: 1.5rem 0 0.5rem; }
.prose p, .prose li { color: var(--text-muted); }
.prose ul { padding-left: 1.4rem; }

.feature-list {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 1rem;
  list-style: none;
  padding: 0;
  margin: 1.5rem 0;
}

.feature-list li {
  background: var(--sand);
  padding: 1rem 1.25rem;
  border-radius: var(--radius);
  border-left: 3px solid var(--teal);
  color: var(--text);
  font-size: 0.92rem;
}

.cta-banner {
  background: linear-gradient(135deg, var(--ocean-deep), var(--teal));
  color: var(--white);
  text-align: center;
  padding: 3.5rem 2rem;
  border-radius: var(--radius);
  margin-top: 2rem;
}

.cta-banner h2 { margin: 0 0 0.75rem; font-size: 1.75rem; }
.cta-banner p { margin: 0 0 1.5rem; opacity: 0.9; }

/* Footer */
.site-footer {
  background: var(--ocean-deep);
  color: rgba(255,255,255,0.85);
  padding: 3.5rem 0 1.5rem;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 2rem;
  margin-bottom: 2.5rem;
}

.footer-grid h4 {
  color: var(--white);
  margin: 0 0 1rem;
  font-size: 0.95rem;
}

.footer-grid p, .footer-grid li {
  font-size: 0.875rem;
  line-height: 1.7;
}

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

.footer-grid a { color: rgba(255,255,255,0.75); }
.footer-grid a:hover { color: var(--teal-light); }

.footer-bottom {
  border-top: 1px solid rgba(255,255,255,0.15);
  padding-top: 1.5rem;
  text-align: center;
  font-size: 0.82rem;
  opacity: 0.7;
}

.social-links {
  display: flex;
  gap: 0.75rem;
  margin-top: 1rem;
}

.social-links a {
  width: 36px;
  height: 36px;
  background: rgba(255,255,255,0.1);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--white);
  font-size: 0.85rem;
  font-weight: 700;
}

.social-links a:hover { background: var(--teal); color: var(--white); }

/* Responsive */
@media (max-width: 960px) {
  .footer-grid { grid-template-columns: 1fr 1fr; }
  .split, .contact-grid { grid-template-columns: 1fr; }
  .split img { order: -1; }
}

@media (max-width: 1024px) {
  .nav-list > li > a,
  .nav-dropdown-trigger {
    padding: 0.45rem 0.65rem;
    font-size: 0.85rem;
  }
}

@media (max-width: 900px) {
  .nav-toggle { display: flex; }

  .main-nav {
    position: fixed;
    top: 0;
    right: 0;
    width: min(340px, 88vw);
    height: 100vh;
    height: 100dvh;
    background: var(--white);
    box-shadow: -8px 0 40px rgba(10, 61, 98, 0.15);
    transform: translateX(100%);
    transition: transform 0.35s cubic-bezier(0.4, 0, 0.2, 1);
    z-index: 200;
    overflow-y: auto;
    padding: calc(var(--header-height) + 1rem) 1.25rem 2rem;
    flex: unset;
    justify-content: flex-start;
  }

  .main-nav.open { transform: translateX(0); }

  .nav-list {
    flex-direction: column;
    align-items: stretch;
    gap: 0.25rem;
  }

  .nav-list > li > a,
  .nav-dropdown-trigger {
    width: 100%;
    justify-content: space-between;
    padding: 0.85rem 1rem;
    font-size: 0.95rem;
    border-radius: 10px;
  }

  .nav-dropdown-menu {
    position: static;
    transform: none;
    opacity: 1;
    visibility: visible;
    pointer-events: none;
    box-shadow: none;
    border: none;
    background: var(--sand);
    border-radius: 10px;
    margin: 0.25rem 0 0.5rem;
    padding: 0;
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease, padding 0.3s;
  }

  .nav-dropdown-menu::before { display: none; }
  .nav-dropdown::after { display: none !important; }

  .nav-dropdown.is-open .nav-dropdown-menu {
    max-height: 360px;
    padding: 0.35rem;
    pointer-events: auto;
  }

  .nav-dropdown-menu a {
    padding: 0.75rem 1rem;
  }

  .nav-cta {
    margin-left: 0 !important;
    margin-top: 0.5rem;
    text-align: center;
    justify-content: center;
  }

  body.nav-open { overflow: hidden; }

  .hero { min-height: 420px; }
  .btn-outline { margin-left: 0; margin-top: 0.75rem; }
  .footer-grid { grid-template-columns: 1fr; }
}