* {
  box-sizing: border-box;
}

html, body {
  margin: 0;
  padding: 0;
  font-family: system-ui, -apple-system, BlinkMacSystemFont, sans-serif;
  color: #111827;
  background: #f9fafb;
}

/* ---------------- Header ---------------- */

.site-header {
  position: sticky;
  top: 0;
  z-index: 1000;
  background: #ffffff;
  border-bottom: 1px solid #e5e7eb;
}

/* Scroll shadow */
.site-header.scrolled {
  box-shadow: 0 2px 10px rgba(0, 0, 0, 0.06);
}

/* Single horizontal flex row */
.nav-container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0.75rem 2rem;

  display: flex;
  justify-content: space-between;
  align-items: center;
}

/* Brand */
.nav-brand {
  font-size: 1.5rem;
  font-weight: 700;
  color: #1d4ed8;
  white-space: nowrap;
}

/* Links */
.nav-links {
  list-style: none;
  display: flex;
  align-items: center;
  gap: 1.75rem;
  margin: 0;
  padding: 0;
}

.nav-links a {
  position: relative;
  font-weight: 500;
  text-decoration: none;
  color: #374151;
  padding: 0.25rem 0;
  transition: color 0.25s ease;
}

/* Hover underline animation */
.nav-links a::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: -4px;
  width: 0%;
  height: 2px;
  background-color: #1d4ed8;
  transition: width 0.25s ease;
}

.nav-links a:hover {
  color: #1d4ed8;
}

.nav-links a:hover::after {
  width: 100%;
}

/* Active link */
.nav-links a.active {
  color: #1d4ed8;
  font-weight: 600;
}

.nav-links a.active::after {
  width: 100%;
}

/* ---------------- Main Content ---------------- */

.content {
  max-width: 960px;
  margin: 0 auto;
  padding: 3rem 2rem;
}

.home h1 {
  font-size: 2.75rem;
  margin-bottom: 1.5rem;
}

.home p {
  font-size: 1.05rem;
  line-height: 1.7;
  margin-bottom: 1.25rem;
  color: #374151;
}

/* ---------- Hamburger Button ---------- */

.nav-toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: 0;
}

.nav-toggle span {
  display: block;
  width: 24px;
  height: 2px;
  background-color: #111827;
  margin: 5px 0;
  transition: transform 0.3s ease, opacity 0.3s ease;
}

/* Hamburger animation */
.nav-toggle.open span:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}

.nav-toggle.open span:nth-child(2) {
  opacity: 0;
}

.nav-toggle.open span:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

/* ---------- Mobile Nav ---------- */
@media (max-width: 768px) {
  .nav-toggle {
    display: block;
  }

  .nav-links {
    position: absolute;
    top: 64px;
    left: 0;
    right: 0;
    background: #ffffff;
    border-bottom: 1px solid #e5e7eb;

    flex-direction: column;
    align-items: flex-start;
    padding: 1.25rem 2rem;
    gap: 1.25rem;

    max-height: 0;
    overflow: hidden;
    opacity: 0;
    pointer-events: none;

    transition:
      max-height 0.35s ease,
      opacity 0.25s ease;
  }

  .nav-links a {
    font-size: 1.1rem;
  }
  
  .nav-links.open {
    max-height: 400px;
    opacity: 1;
    pointer-events: auto;
  }
}