/* Modern Header Styles */
header {
  width: 100%;
  position: fixed;
  top: 0;
  left: 0;
  z-index: 1000;
  transition: var(--transition);
  background: var(--glass-bg);
  backdrop-filter: blur(var(--glass-blur));
  -webkit-backdrop-filter: blur(var(--glass-blur));
  border-bottom: 1px solid var(--glass-border);
}

header.sticky {
  padding: 0.5rem 0;
  box-shadow: var(--shadow-md);
}

#header-nav .container {
  display: flex;
  justify-content: space-between;
  align-items: center;
  height: var(--header-h);
}

.brand h1 {
  font-size: 1.5rem;
  font-weight: 700;
  letter-spacing: -1px;
}

.brand a {
  color: var(--primary);
  text-decoration: none;
}

/* Navigation */
#menu ul {
  display: flex;
  list-style: none;
  gap: 2rem;
  align-items: center;
}

#menu a {
  text-decoration: none;
  color: var(--text-main);
  font-weight: 500;
  font-size: 0.95rem;
  transition: var(--transition);
  position: relative;
}

#menu a:hover,
#menu a.active-link {
  color: var(--primary);
}

#menu a::after {
  content: '';
  position: absolute;
  bottom: -4px;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--primary);
  transition: var(--transition);
}

#menu a:hover::after,
#menu a.active-link::after {
  width: 100%;
}

/* Theme Toggle */
#theme-toggle {
  background: var(--bg-soft);
  border: 1px solid var(--border-color);
  color: var(--text-main);
  width: 40px;
  height: 40px;
  border-radius: 10px;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: var(--transition);
}

#theme-toggle:hover {
  background: var(--primary);
  color: white;
  transform: rotate(15deg);
}

/* Mobile Menu Link */
.menu-link {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  z-index: 1100;
}

.menu-link span {
  width: 25px;
  height: 2px;
  background: var(--text-main);
  transition: var(--transition);
}

/* Mobile View */
@media (max-width: 768px) {
  .menu-link {
    display: flex;
  }

  #menu {
    position: fixed;
    top: 0;
    right: -100%;
    width: 80%;
    max-width: 300px;
    height: 100vh;
    background: var(--bg-surface);
    box-shadow: var(--shadow-lg);
    transition: var(--transition);
    padding: 8rem 2rem;
  }

  #menu.menu-open {
    right: 0;
  }

  #menu ul {
    flex-direction: column;
    align-items: flex-start;
  }

  #menu a {
    font-size: 1.5rem;
    font-weight: 600;
  }
}