:root {
  --bg: #f5f7fa;
  --text: #333;
  --header: #1e2a38;
  --hero: #2f4f6f;
}

body.dark {
  --bg: #0f1720;
  --text: #e5e7eb;
  --header: #020617;
  --hero: #1e293b;
}

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

.container {
  max-width: 900px;
  margin: auto;
  padding: 20px;
}

header {
  background: var(--header);
  color: white;
}

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

.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 20px;
}

.logo img {
  height: 40px;
}

nav a {
  color: white;
  margin-left: 15px;
  text-decoration: none;
}

.hero {
  background: var(--hero);
  color: white;
  text-align: center;
  padding: 60px 20px;
}

.hero-logo {
  height: 80px;
  margin-bottom: 20px;
}

section {
  margin: 40px 0;
}

footer {
  background: var(--header);
  color: white;
  text-align: center;
  padding: 15px 0;
}

#theme-toggle {
  background: none;
  border: 1px solid #ccc;
  color: white;
  padding: 6px 10px;
  border-radius: 6px;
  cursor: pointer;
}