.header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  background: #ffffff;
  backdrop-filter: none;
  -webkit-backdrop-filter: none;
  border-bottom: 0.0625em solid rgba(255, 255, 255, 0.25);
  z-index: 1000;
  box-shadow: 0 0.0625em 0.75em rgba(0, 0, 0, 0.06);
}

.nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 0.3em 0;
}

.logo {
  display: flex;
  align-items: center;
  text-decoration: none;
  color: var(--text);
  font-size: 1.375em;
  font-weight: 800;
  letter-spacing: -0.03em;
  transition: transform var(--transition);
}

.logo:hover {
  transform: scale(1.04);
}

.logo-icon {
  font-size: 1.625em;
  margin-right: 0.5em;
}

.logo-text {
  background: linear-gradient(135deg, var(--primary) 0%, #a855f7 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.nav-links {
  display: flex;
  gap: 0.375em;
  align-items: center;
}

/* ===== Language switcher ===== */
.language-switcher {
  display: inline-flex;
  align-items: center;
  gap: 0.125em;
  margin-left: 0.75em;
  padding: 0.1875em;
  background: rgba(99, 102, 241, 0.06);
  border: 0.0625em solid rgba(99, 102, 241, 0.12);
  border-radius: var(--radius-sm);
}

.lang-btn {
  background: transparent;
  border: none;
  cursor: pointer;
  padding: 0.25em 0.5em;
  font-family: inherit;
  font-size: 0.75em;
  font-weight: 600;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  color: var(--text-muted);
  border-radius: calc(var(--radius-sm) - 0.125em);
  transition: color var(--transition), background var(--transition);
  line-height: 1;
}

.lang-btn:hover {
  color: var(--primary);
  background: rgba(99, 102, 241, 0.1);
}

.lang-btn.active {
  color: #ffffff;
  background: linear-gradient(135deg, var(--primary) 0%, #a855f7 100%);
  box-shadow: 0 0.0625em 0.25em rgba(99, 102, 241, 0.25);
}

.lang-btn:focus {
  outline: 0.125em solid var(--primary);
  outline-offset: 0.125em;
}

.nav-toggle {
  display: none;
  background: transparent;
  border: none;
  cursor: pointer;
  width: 2.75em;
  height: 2.75em;
  border-radius: var(--radius-sm);
  align-items: center;
  justify-content: center;
  flex-direction: column;
  position: relative;
  z-index: 1001;
  transition: background var(--transition);
}

.nav-toggle:hover {
  background: rgba(99, 102, 241, 0.06);
}

.nav-toggle:focus {
  outline: 0.125em solid var(--primary);
  outline-offset: 0.125em;
}

.hamburger-line {
  display: block;
  position: absolute;
  left: 50%;
  width: 1.375em;
  height: 0.125em;
  background: var(--text);
  border-radius: 0.125em;
  transform: translate(-50%, -50%);
  transition: transform 0.3s cubic-bezier(0.4, 0, 0.2, 1),
              opacity 0.2s ease,
              background-color 0.3s ease,
              top 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  transform-origin: center;
}

.nav-toggle .hamburger-line:nth-child(1) { top: calc(50% - 0.4375em); }
.nav-toggle .hamburger-line:nth-child(2) { top: 50%; }
.nav-toggle .hamburger-line:nth-child(3) { top: calc(50% + 0.4375em); }

/* Animate to X when open */
.header.nav-open .nav-toggle .hamburger-line:nth-child(1) {
  top: 50%;
  transform: translate(-50%, -50%) rotate(45deg);
}
.header.nav-open .nav-toggle .hamburger-line:nth-child(2) {
  opacity: 0;
}
.header.nav-open .nav-toggle .hamburger-line:nth-child(3) {
  top: 50%;
  transform: translate(-50%, -50%) rotate(-45deg);
}

.nav-link {
  text-decoration: none;
  color: var(--text-muted);
  font-weight: 500;
  font-size: 0.875em;
  padding: 0.5em 1em;
  border-radius: var(--radius-sm);
  transition: all var(--transition);
  position: relative;
  letter-spacing: -0.01em;
}

.nav-link:hover {
  color: var(--primary);
  background: rgba(99, 102, 241, 0.08);
}

.nav-link.active {
  color: var(--primary);
  background: rgba(99, 102, 241, 0.1);
  font-weight: 600;
}

.nav-link.active::after {
  content: '';
  position: absolute;
  bottom: -0.125em;
  left: 50%;
  transform: translateX(-50%);
  width: 1.125em;
  height: 0.125em;
  background: linear-gradient(90deg, var(--primary), #a855f7);
  border-radius: 0.0625em;
}

@media (max-width: 64em) {
  .nav-toggle {
    display: inline-flex;
  }

  .nav {
    gap: 0;
    flex-wrap: wrap;
  }

  .nav-links {
    display: none;
    flex-direction: column;
    align-items: stretch;
    gap: 0.25em;
    width: 100%;
    margin-top: 0.5em;
    padding: 0.625em 0 0.3125em 0;
    border-top: 0.0625em solid rgba(99, 102, 241, 0.12);
    position: relative;
    z-index: 1000;
  }

  .header.nav-open .nav-links {
    display: flex;
  }

  .nav-link {
    padding: 0.75em 0.75em;
    font-size: 0.875em;
  }

  .nav-link.active::after {
    display: none;
  }

  .language-switcher {
    margin-left: 0;
    margin-top: 0.5em;
    align-self: flex-start;
  }
}