/* ── Header ── */
header {
  background: rgba(10, 10, 12, 0.72);
  backdrop-filter: blur(20px) saturate(180%);
  -webkit-backdrop-filter: blur(20px) saturate(180%);
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
  padding: 0 2rem;
  height: 64px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  position: sticky;
  top: 0;
  z-index: 100;
}

[data-theme="light"] header {
  background: rgba(255, 255, 255, 0.72);
  border-bottom-color: rgba(0, 0, 0, 0.1);
}

.header-left {
  display: flex;
  align-items: center;
  gap: 3rem;
}

.logo { height: 40px; }
.logo-light { display: none; }
[data-theme="light"] .logo-dark { display: none; }
[data-theme="light"] .logo-light { display: inline; }

nav {
  display: flex;
  align-items: center;
  gap: 1.5rem;
}

nav a {
  color: var(--text);
  text-decoration: none;
  font-weight: 500;
  font-size: 1.05rem;
  white-space: nowrap;
  transition: color 0.2s;
}

nav a:hover { color: var(--primary); }

nav a.nav-cta {
  background: var(--primary);
  color: #ffffff;
  padding: 0.45rem 0.95rem;
  border-radius: 8px;
  font-weight: 600;
  transition: background 0.2s, transform 0.2s, box-shadow 0.2s;
}

nav a.nav-cta:hover {
  background: #b83aa8;
  color: #ffffff;
  transform: translateY(-1px);
  box-shadow: 0 4px 12px rgba(var(--primary-rgb), 0.35);
}

/* Nav group (dropdown under the brand label) */
.nav-group {
  position: relative;
  display: inline-flex;
  align-items: center;
}
.nav-group-trigger {
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
}
.nav-group-caret {
  font-size: 0.7em;
  opacity: 0.75;
  transition: transform 0.2s;
}
.nav-group:hover .nav-group-caret,
.nav-group:focus-within .nav-group-caret {
  transform: rotate(180deg);
}
.nav-submenu {
  position: absolute;
  top: calc(100% + 0.5rem);
  left: 0;
  min-width: 220px;
  display: flex;
  flex-direction: column;
  gap: 0.15rem;
  background: rgba(10, 10, 12, 0.96);
  backdrop-filter: blur(20px) saturate(180%);
  -webkit-backdrop-filter: blur(20px) saturate(180%);
  border: 1px solid rgba(255, 255, 255, 0.08);
  border-radius: 10px;
  padding: 0.5rem;
  opacity: 0;
  visibility: hidden;
  transform: translateY(-4px);
  transition: opacity 0.2s, visibility 0.2s, transform 0.2s;
  z-index: 110;
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.35);
}
[data-theme="light"] .nav-submenu {
  background: rgba(255, 255, 255, 0.96);
  border-color: rgba(0, 0, 0, 0.08);
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.12);
}
.nav-group:hover .nav-submenu,
.nav-group:focus-within .nav-submenu {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}
.nav-submenu a {
  padding: 0.5rem 0.75rem;
  border-radius: 6px;
  font-size: 0.95rem;
  white-space: nowrap;
}
.nav-submenu a:hover {
  background: rgba(var(--primary-rgb), 0.12);
}

.header-right {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.theme-toggle, .lang-select {
  background: none;
  border: 1px solid var(--border);
  color: var(--text);
  padding: 0.4rem 0.75rem;
  border-radius: 6px;
  cursor: pointer;
  font-size: 0.95rem;
  transition: border-color 0.2s;
}

.theme-toggle:hover, .lang-select:hover {
  border-color: var(--primary);
}

.theme-toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  padding: 0;
}

.theme-toggle svg {
  width: 18px;
  height: 18px;
  fill: currentColor;
}

.lang-select {
  appearance: none;
  padding-right: 1.5rem;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 12 12'%3E%3Cpath fill='%23666' d='M6 8L1 3h10z'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 0.5rem center;
}

/* Burger / mobile menu toggle — hidden by default on desktop */
.menu-toggle {
  display: none;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  padding: 0;
  gap: 4px;
  background: none;
  border: 1px solid var(--border);
  color: var(--text);
  border-radius: 6px;
  cursor: pointer;
  transition: border-color 0.2s;
}

.menu-toggle:hover { border-color: var(--primary); }

.menu-toggle span {
  display: block;
  width: 18px;
  height: 2px;
  background: currentColor;
  border-radius: 2px;
  transition: transform 0.25s ease, opacity 0.2s ease;
}

.menu-toggle.is-open span:nth-child(1) { transform: translateY(6px) rotate(45deg); }
.menu-toggle.is-open span:nth-child(2) { opacity: 0; }
.menu-toggle.is-open span:nth-child(3) { transform: translateY(-6px) rotate(-45deg); }