/* ============================================================
SITE HEADER
============================================================ */

.site-header {
  position: fixed;
  top: 0;
  width: 100%;
  height: var(--nav-height);
  background: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
  z-index: 100;
  backdrop-filter: blur(8px);
}

.site-nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--gutter);
  height: var(--nav-height);
}

.nav-logo {
  font-weight: 700;
  font-size: 1.1rem;
  color: var(--color-accent-light);
}

/* ============================================================
DESKTOP NAV LINKS
============================================================ */

.nav-links {
  display: flex;
  gap: 1.5rem;
}

.nav-link {
  color: var(--color-text-muted);
  font-size: 0.9rem;
  position: relative;
  transition: color var(--transition-base);
}

.nav-link:hover {
  color: var(--color-text);
}

/* underline animation */

.nav-link::after {
  content: "";
  position: absolute;
  bottom: -4px;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--color-accent);
  transition: width var(--transition-base);
}

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

@media (max-width: 768px) {
  .nav-links {
    display: none;
  }
}

/* ============================================================
HAMBURGER BUTTON
============================================================ */

.nav-toggle {
  display: none;
}

@media (max-width: 768px) {
  .nav-toggle {
    display: flex;
    flex-direction: column;
    justify-content: center;
    gap: 4px;
    width: 2rem;
    height: 2rem;
    background: none;
    border: none;
    cursor: pointer;
  }
}

.hamburger-line {
  width: 100%;
  height: 2px;
  background: var(--color-text);
  border-radius: 2px;
  transition: transform var(--transition-base), opacity var(--transition-base);
}

/* hamburger animation */

.nav-toggle[aria-expanded="true"] .hamburger-line:nth-child(1) {
  transform: translateY(6px) rotate(45deg);
}

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

.nav-toggle[aria-expanded="true"] .hamburger-line:nth-child(3) {
  transform: translateY(-6px) rotate(-45deg);
}

/* ============================================================
SLIDE MENU
============================================================ */

.slide-menu {
  position: fixed;
  top: 0;
  right: 0;
  width: var(--slide-menu-width);
  height: 100vh;
  background: var(--color-surface);
  border-left: 1px solid var(--color-border);
  z-index: 150;
  padding: 2rem;
  transform: translateX(100%);
  transition: transform var(--transition-slide);
}

.slide-menu.is-open {
  transform: translateX(0);
}

.slide-menu-close {
  position: absolute;
  top: 1rem;
  right: 1rem;
  background: none;
  border: none;
  font-size: 1.5rem;
  color: var(--color-text-muted);
  cursor: pointer;
}

.slide-menu-close:hover {
  color: var(--color-text);
}

/* ============================================================
STAGGERED LINKS
============================================================ */

@keyframes link-enter {
  from {
    opacity: 0;
    transform: translateX(16px);
  }
  to {
    opacity: 1;
    transform: translateX(0);
  }
}

.slide-menu-links {
  display: flex;
  flex-direction: column;
  gap: 1rem;
  margin-top: 3rem;
}

.slide-menu-link {
  opacity: 0;
  font-size: 1.2rem;
  color: var(--color-text-muted);
}

.slide-menu-link:hover {
  color: var(--color-text);
}

.slide-menu.is-open .slide-menu-link {
  animation: link-enter 250ms ease-out forwards;
}

.slide-menu-link:nth-child(1) { animation-delay: 0ms; }
.slide-menu-link:nth-child(2) { animation-delay: 50ms; }
.slide-menu-link:nth-child(3) { animation-delay: 100ms; }
.slide-menu-link:nth-child(4) { animation-delay: 150ms; }

/* ============================================================
OVERLAY
============================================================ */

.slide-overlay {
  position: fixed;
  inset: 0;
  background: var(--color-overlay);
  z-index: 120;
  opacity: 0;
  pointer-events: none;
  transition: opacity var(--transition-slide);
}

.slide-overlay.is-open {
  opacity: 1;
  pointer-events: auto;
}