:root {
  --accent: #00b4c6;
  --dark: #0a192f;
  --text: #1a1a1a;
  --background: #f9fbfc;
  --link: #007acc;
}

html, body {
  height: 100%;
}

body {
  font-family: 'Segoe UI', 'Inter', sans-serif;
  background: var(--background);
  color: var(--text);
  line-height: 1.7;
  margin: 0;
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

.container {
  max-width: 900px;
  margin: 0 auto;
  padding: 2rem 1.5rem;
}

header {
  background: var(--dark);
  color: white;
  text-align: center;
  padding: 3rem 1.5rem;
}

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

header p {
  font-size: 1.1rem;
  color: var(--accent);
}

nav {
  margin-top: 2rem;
}

nav a {
  margin: 0 1rem;
  color: var(--accent);
  text-decoration: none;
  font-weight: 600;
  position: relative;
  transition: color 0.3s ease;
}

nav a::after {
  content: '';
  display: block;
  height: 2px;
  background: var(--accent);
  transition: width 0.3s;
  width: 0;
  position: absolute;
  bottom: -4px;
  left: 0;
}

nav a:hover {
  color: white;
}

nav a:hover::after {
  width: 100%;
}

main {
  flex: 1;
}

main h2 {
  font-size: 1.8rem;
  margin-bottom: 1rem;
  color: var(--dark);
}

main h3 {
  margin-top: 2rem;
  margin-bottom: 0.5rem;
  color: var(--accent);
  font-size: 1.3rem;
}

main p {
  margin-bottom: 1rem;
}

main ul {
  margin-left: 1.5rem;
  margin-bottom: 2rem;
}

a {
  color: var(--link);
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

footer {
  text-align: center;
  padding: 1rem 0;
  font-size: 0.85rem;
  background: #e8ecf0;
  color: #555;
}
/* Theme Toggle Button */
#theme-toggle {
  position: absolute;
  top: 1rem;
  right: 1rem;
  background: none;
  border: none;
  font-size: 1.5rem;
  cursor: pointer;
  color: white;
}

/* Dark Mode Styles */
body.dark {
  background: #121212;
  color: #e0e0e0;
}

body.dark header {
  background: #1e1e1e;
  color: #ffffff;
}

body.dark nav a {
  color: #64ffda;
}

body.dark a {
  color: #80cbc4;
}

body.dark footer {
  background: #1e1e1e;
  color: #ccc;
}