:root {
  --primary-color: #007bff;
  --secondary-color: #0056b3;
  --bg-light: #f4f4f4;
  --bg-dark: #333;
  --text-light: #333;
  --text-dark: #f4f4f4;
  --font-main: 'Arial', sans-serif;
}

[data-theme='dark'] {
  --bg-light: #333;
  --bg-dark: #f4f4f4;
  --text-light: #f4f4f4;
  --text-dark: #333;
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: var(--font-main);
  background-color: var(--bg-light);
  color: var(--text-light);
  line-height: 1.6;
  transition: background-color 0.3s, color 0.3s;
}

header {
  background: var(--primary-color);
  padding: 1rem 0;
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: 0 2px 5px rgba(0,0,0,0.1);
}

nav ul {
  list-style: none;
  display: flex;
  justify-content: center;
  gap: 2rem;
}

nav a {
  color: white;
  text-decoration: none;
  font-weight: bold;
  padding: 0.5rem 1rem;
  border-radius: 5px;
  transition: background 0.3s;
}

nav a:hover {
  background: var(--secondary-color);
}

main {
  max-width: 1200px;
  margin: 0 auto;
  padding: 2rem;
}

.hero {
  text-align: center;
  padding: 4rem 0;
}

.hero h1 {
  font-size: 3rem;
  margin-bottom: 1rem;
  background: linear-gradient(45deg, var(--primary-color), #00d4ff);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero p {
  font-size: 1.5rem;
  margin-bottom: 2rem;
  opacity: 0.9;
}

#message {
  font-size: 1.4em;
  margin: 20px 0;
  padding: 1rem;
  background: rgba(255,255,255,0.1);
  border-radius: 10px;
  border-left: 5px solid var(--primary-color);
}

.btn {
  display: inline-block;
  padding: 12px 24px;
  background: var(--primary-color);
  color: white;
  border: none;
  border-radius: 50px;
  cursor: pointer;
  font-size: 1.1em;
  transition: all 0.3s;
  text-decoration: none;
}

.btn:hover {
  background: var(--secondary-color);
  transform: translateY(-2px);
  box-shadow: 0 5px 15px rgba(0,123,255,0.4);
}

#themeToggle {
  position: fixed;
  top: 20px;
  right: 20px;
  background: var(--primary-color);
  color: white;
  border: none;
  padding: 10px;
  border-radius: 50%;
  cursor: pointer;
}

.ideas-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 2rem;
  margin-top: 3rem;
}

.idea-card {
  background: white;
  padding: 2rem;
  border-radius: 15px;
  box-shadow: 0 10px 30px rgba(0,0,0,0.1);
  transition: transform 0.3s;
}

.idea-card:hover {
  transform: translateY(-10px);
}

footer {
  text-align: center;
  padding: 2rem;
  background: var(--bg-dark);
  color: var(--text-dark);
  margin-top: 4rem;
}

@media (max-width: 768px) {
  .hero h1 { font-size: 2rem; }
  nav ul { flex-direction: column; align-items: center; gap: 1rem; }
}