header {
  padding: 20px 0;
  background-color: var(--feature-bg);
  box-shadow: 0 2px 10px rgba(0,0,0,0.1);
  position: sticky;
  top: 0;
  z-index: 100;
}

.header-content {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.theme-toggle {
  margin-left: 20px;
}

#theme-toggle-btn {
  background: none;
  border: none;
  font-size: 24px;
  cursor: pointer;
  padding: 5px;
  border-radius: 50%;
  transition: background-color 0.3s;
}

#theme-toggle-btn:hover {
  background-color: rgba(0,0,0,0.1);
}

.logo {
  font-size: 28px;
  font-weight: 700;
  color: var(--primary);
}

.logo span {
  color: var(--secondary);
}

nav ul {
  display: flex;
  list-style: none;
  align-items: center;
}

nav ul li {
  margin-left: 30px;
}

nav ul li a {
  text-decoration: none;
  color: var(--dark);
  font-weight: 500;
  padding: 8px 16px;
  border-radius: 20px;
  transition: all 0.3s ease;
  position: relative;
  display: inline-block;
}

nav ul li a:not(.btn):hover {
  color: var(--primary);
  background-color: rgba(107, 154, 98, 0.1);
}

nav ul li a:not(.btn):after {
  content: '';
  position: absolute;
  width: 0;
  height: 2px;
  bottom: 0;
  left: 50%;
  background-color: var(--primary);
  transition: all 0.3s ease;
  transform: translateX(-50%);
}

nav ul li a:not(.btn):hover:after {
  width: 60%;
}

nav ul li a.btn {
  padding: 10px 25px;
  margin-top: 0;
  margin-bottom: 0;
}