/* ============================================
   SOL+ — Header / Navigation
   ============================================ */

.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  height: var(--header-height);
  background-color: var(--color-white);
  transition: box-shadow var(--transition-fast), background-color var(--transition-fast);
}

.site-header.is-scrolled {
  box-shadow: 0 2px 12px rgba(0,0,0,0.08);
}

/* Transparent variant for hero overlap */
.site-header.header--transparent {
  background-color: transparent;
}

.site-header.header--transparent .nav-link {
  color: rgba(255,255,255,0.9);
}

.site-header.header--transparent .site-header__logo {
  color: #fff;
}

.site-header.header--transparent .site-header__logo img {
  filter: brightness(0) invert(1);
}

.site-header.header--transparent.is-scrolled {
  background-color: var(--color-white);
}

.site-header.header--transparent.is-scrolled .nav-link {
  color: var(--color-charcoal);
}

.site-header.header--transparent.is-scrolled .site-header__logo {
  color: var(--color-teal-700);
}

.site-header.header--transparent.is-scrolled .site-header__logo img {
  filter: none;
}

.site-header__inner {
  max-width: var(--content-width);
  margin: 0 auto;
  padding: 0 var(--space-lg);
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-xl);
}

/* ── Logo ── */
.site-header__logo {
  text-decoration: none;
  flex-shrink: 0;
  display: flex;
  align-items: center;
  line-height: 1;
}

.site-header__logo img {
  height: 36px;
  width: auto;
  display: block;
  transition: filter var(--transition-fast);
}

/* ── Nav ── */
.site-nav {
  display: flex;
  align-items: center;
  gap: 0;
}

.nav-list {
  display: flex;
  align-items: center;
  gap: var(--space-lg);
  list-style: none;
}

.nav-link {
  font-family: var(--font-body);
  font-size: 14px;
  font-weight: 500;
  color: var(--color-charcoal);
  text-decoration: none;
  letter-spacing: 0.04em;
  transition: color var(--transition-fast);
  white-space: nowrap;
}

.nav-link:hover {
  color: var(--color-teal-700);
}

.nav-cta {
  margin-left: var(--space-md);
}

/* ── Hamburger ── */
.hamburger {
  display: none;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  gap: 6px;
  width: 44px;
  height: 44px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 0;
  z-index: 1100;
}

.hamburger__line {
  display: block;
  width: 24px;
  height: 2px;
  background-color: var(--color-charcoal);
  transition: transform var(--transition-fast), opacity var(--transition-fast);
}

.hamburger.is-open .hamburger__line:nth-child(1) {
  transform: translateY(8px) rotate(45deg);
}

.hamburger.is-open .hamburger__line:nth-child(2) {
  opacity: 0;
}

.hamburger.is-open .hamburger__line:nth-child(3) {
  transform: translateY(-8px) rotate(-45deg);
}

/* Transparent header hamburger */
.site-header.header--transparent .hamburger__line {
  background-color: #fff;
}

.site-header.header--transparent.is-scrolled .hamburger__line {
  background-color: var(--color-charcoal);
}

/* ── Mobile Menu ── */
.mobile-menu {
  position: fixed;
  inset: 0;
  background-color: var(--color-teal-900);
  z-index: 999;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: var(--space-xl);
  opacity: 0;
  visibility: hidden;
  transition: opacity 0.4s ease, visibility 0.4s ease;
}

.mobile-menu.is-open {
  opacity: 1;
  visibility: visible;
}

.mobile-menu__list {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-lg);
  list-style: none;
}

.mobile-menu__list li {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.35s ease, transform 0.35s ease;
}

.mobile-menu.is-open .mobile-menu__list li {
  opacity: 1;
  transform: translateY(0);
}

.mobile-menu.is-open .mobile-menu__list li:nth-child(1) { transition-delay: 0.1s; }
.mobile-menu.is-open .mobile-menu__list li:nth-child(2) { transition-delay: 0.17s; }
.mobile-menu.is-open .mobile-menu__list li:nth-child(3) { transition-delay: 0.24s; }
.mobile-menu.is-open .mobile-menu__list li:nth-child(4) { transition-delay: 0.31s; }
.mobile-menu.is-open .mobile-menu__list li:nth-child(5) { transition-delay: 0.38s; }
.mobile-menu.is-open .mobile-menu__list li:nth-child(6) { transition-delay: 0.45s; }

.mobile-menu__link {
  font-family: var(--font-heading-ja);
  font-size: 24px;
  font-weight: 600;
  color: rgba(255,255,255,0.9);
  text-decoration: none;
  letter-spacing: 0.08em;
  transition: color var(--transition-fast);
}

.mobile-menu__link:hover {
  color: var(--color-teal-300);
}

.mobile-menu__cta {
  margin-top: var(--space-md);
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.35s ease, transform 0.35s ease;
}

.mobile-menu.is-open .mobile-menu__cta {
  opacity: 1;
  transform: translateY(0);
  transition-delay: 0.45s;
}

/* ── Responsive ── */
@media (max-width: 1023px) {
  .nav-list {
    gap: var(--space-md);
  }
}

@media (max-width: 767px) {
  .site-nav {
    display: none;
  }

  .hamburger {
    display: flex;
  }
}