:root {
  --bg-color: #ffffff;
  --text-color: #222;
  --accent-color: #2a9d8f;
  --nav-bg: #f9f9f9;
}

body.dark-theme {
  --bg-color: #121212;
  --text-color: #f5f5f5;
  --accent-color: #4dd0e1;
  --nav-bg: #1e1e1e;
}

body {
  margin: 0;
  font-family: "Poppins", sans-serif;
  background-color: var(--bg-color);
  color: var(--text-color);
  transition: background 0.3s ease, color 0.3s ease;
}

.navbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  background-color: var(--nav-bg);
  padding: 1rem 2rem;
  box-shadow: 0 2px 6px rgba(0,0,0,0.1);
  position: sticky;
  top: 0;
  z-index: 1000;
}

.logo {
  font-size: 1.5rem;
  font-weight: bold;
  color: var(--accent-color);
}

.nav-links {
  list-style: none;
  display: flex;
  gap: 1.2rem;
  align-items: center;
}

.nav-links a {
  text-decoration: none;
  color: var(--text-color);
  font-weight: 500;
  transition: color 0.3s;
}

.nav-links a:hover {
  color: var(--accent-color);
}

#theme-toggle {
  background: none;
  border: none;
  font-size: 1.2rem;
  cursor: pointer;
}

.hero {
  text-align: center;
  padding: 4rem 1rem;
  background: linear-gradient(135deg, var(--accent-color), #264653);
  color: #fff;
}

.hero h1 {
  font-size: 2.2rem;
  margin-bottom: 1rem;
}

.hero p {
  font-size: 1.1rem;
}

.content {
  max-width: 900px;
  margin: 2rem auto;
  padding: 0 1rem;
}

.content h2, .content h3 {
  color: var(--accent-color);
}

footer {
  text-align: center;
  padding: 1.5rem;
  background: var(--nav-bg);
  font-size: 0.9rem;
}

@media (max-width: 768px) {
  .nav-links {
    flex-direction: column;
    background: var(--nav-bg);
    position: absolute;
    top: 60px;
    right: 0;
    width: 100%;
    display: none;
  }
  .nav-links.active {
    display: flex;
  }
}