/* Reset & base */

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

html {
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  font-display: swap;
}

body {
  margin: 0;
  padding: 0;
  background-color: #f9fafb;
  color: #222222;
  line-height: 1.6;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  font-weight: 400;
}

/* Navigation */

.top-nav {
  background-color: #004080;
  box-shadow: 0 2px 6px rgb(0 0 0 / 0.15);
  position: sticky;
  top: 0;
  z-index: 1000;
}

.top-nav ul {
  display: flex;
  justify-content: center;
  list-style: none;
  margin: 0;
  padding: 0.75rem 1rem;
  gap: 1.2rem;
  flex-wrap: wrap;
}

.top-nav li a {
  color: #ffffff;
  text-decoration: none;
  font-weight: 600;
  padding: 0.4rem 0.7rem;
  border-radius: 4px;
  transition: background-color 0.25s ease-in-out;
}

.top-nav li a:hover,
.top-nav li a:focus {
  background-color: #0066cc;
  outline: none;
}

/* Header */

header {
  background: linear-gradient(135deg, #0059b3 0%, #003366 100%);
  color: white;
  text-align: center;
  padding: 3rem 1rem 2.5rem;
  flex-shrink: 0;
}

header h1 {
  font-size: 2.75rem;
  margin: 0 0 0.25rem;
  font-weight: 700;
  line-height: 1.1;
}

header .subtitle {
  font-size: 1.25rem;
  font-weight: 400;
  max-width: 600px;
  margin: 0 auto;
  color: #cbd5e1;
}

/* Main content */

main {
  flex-grow: 1;
  max-width: 960px;
  margin: 2rem auto;
  padding: 0 1rem;
  display: grid;
  grid-template-columns: 1fr;
  gap: 2.5rem;
}

/* Sections styling */

section h2 {
  font-size: 1.8rem;
  font-weight: 700;
  margin-bottom: 0.8rem;
  color: #003366;
  border-bottom: 3px solid #0073e6;
  padding-bottom: 0.3rem;
}

section p {
  margin-top: 0;
  margin-bottom: 1.2rem;
  color: #2d2d2d;
  font-weight: 400;
  line-height: 1.6;
}

section ul {
  padding-left: 1.4rem;
  margin-top: 0.5rem;
  margin-bottom: 1rem;
  color: #333333;
}

section ul li {
  margin-bottom: 0.6rem;
  font-weight: 500;
}

/* Strong emphasis with improved contrast */

strong {
  color: #004080; /* dark blue for strong emphasis */
  font-weight: 700;
}

/* FAQ section */

#faq details {
  margin-bottom: 1rem;
  background-color: #e9f0ff;
  padding: 1rem 1.25rem;
  border-radius: 8px;
  border: 1px solid #aac8ff;
}

#faq summary {
  font-weight: 600;
  font-size: 1.1rem;
  cursor: pointer;
  color: #003366;
  outline-offset: 4px;
}

#faq details[open] {
  background-color: #d6e4ff;
}

/* Footer */

footer {
  background-color: #222222;
  color: #ffffff; /* pure white for max contrast */
  text-align: center;
  padding: 1.5rem 1rem;
  min-height: 80px; /* reserve space to prevent layout shift */
  line-height: 1.5;
  font-size: 0.9rem;
  user-select: none;
  font-weight: 500;
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  flex-shrink: 0;
}

/* Responsive adjustments */

@media (min-width: 768px) {
  main {
    grid-template-columns: repeat(2, 1fr);
    gap: 3rem;
  }

  #faq details {
    max-width: 600px;
  }
}

@media (min-width: 1024px) {
  main {
    grid-template-columns: repeat(3, 1fr);
  }
}