:root {
  --bg-color: #fdfdfd;
  --text-color: #333;
  --header-bg: #fff;
  --header-border: #eee;
  --link-color: #007bff;
  --nav-link-color: #555;
  --footer-color: #888;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg-color: #121212;
    --text-color: #eee;
    --header-bg: #1c1c1c;
    --header-border: #333;
    --link-color: #1e90ff;
    --nav-link-color: #bbb;
    --footer-color: #777;
  }
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    line-height: 1.6;
    margin: 0;
    padding: 0;
    background-color: var(--bg-color);
    color: var(--text-color);
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}

header {
    background: var(--header-bg);
    border-bottom: 1px solid var(--header-border);
    padding: 1rem 0;
}

.header-container {
    width: 80%;
    max-width: 800px;
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

header a {
    color: var(--text-color);
    text-decoration: none;
    font-weight: 500;
}

nav {
    width: 80%;
    max-width: 800px;
    margin: 1rem auto;
}

nav ul {
    list-style: none;
    padding: 0;
    margin: 0;
    display: flex;
    gap: 1.5rem;
}

nav a {
    color: var(--nav-link-color);
    text-decoration: none;
    font-size: 1.1rem;
}

nav a:hover {
    text-decoration: underline;
}

main {
    flex-grow: 1;
    width: 80%;
    max-width: 800px;
    margin: 2rem auto;
}

h1 {
    font-size: 2.5rem;
    margin-bottom: 0.5rem;
}

p {
    font-size: 1.2rem;
}

a {
    color: var(--link-color);
}

a:hover {
    text-decoration: none;
}

footer {
    text-align: center;
    padding: 2rem 0;
    margin-top: auto;
    color: var(--footer-color);
    font-size: 0.9rem;
}

@media (max-width: 600px) {
  nav ul {
    flex-direction: column;
    align-items: center;
    gap: 1rem;
  }

  .header-container {
    flex-direction: column;
    gap: 0.5rem;
  }
}