:root {
  --bg-color: #0f172a;
  --card-bg: #1e293b;
  --text-main: #f8fafc;
  --text-muted: #94a3b8;
  --accent-cyan: #38bdf8;
  --accent-indigo: #818cf8;
  --border-color: #334155;
}

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

body {
  font-family: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
  background-color: var(--bg-color);
  color: var(--text-main);
  line-height: 1.6;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

header {
  background-color: rgba(15, 23, 42, 0.9);
  border-bottom: 1px solid var(--border-color);
  position: sticky;
  top: 0;
  z-index: 100;
  backdrop-filter: blur(8px);
}

.nav-container {
  max-width: 1100px;
  margin: 0 auto;
  padding: 1rem 2rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.logo-group {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  text-decoration: none;
  color: var(--text-main);
  font-weight: 700;
  font-size: 1.25rem;
}

.logo-group img {
  width: 32px;
  height: 32px;
}

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

nav a {
  color: var(--text-muted);
  text-decoration: none;
  font-weight: 500;
  transition: color 0.2s ease;
}

nav a:hover, nav a.active {
  color: var(--accent-cyan);
}

main {
  max-width: 1100px;
  margin: 0 auto;
  padding: 3rem 2rem;
  flex: 1;
  width: 100%;
}

.hero {
  text-align: center;
  padding: 3rem 1rem;
  margin-bottom: 3rem;
  background: linear-gradient(135deg, rgba(56, 189, 248, 0.1), rgba(129, 140, 248, 0.1));
  border: 1px solid var(--border-color);
  border-radius: 12px;
}

.hero h1 {
  font-size: 2.75rem;
  margin-bottom: 1rem;
  background: linear-gradient(90deg, var(--accent-cyan), var(--accent-indigo));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.hero p {
  font-size: 1.2rem;
  color: var(--text-muted);
  max-width: 700px;
  margin: 0 auto;
}

.grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 1.5rem;
  margin-top: 2rem;
}

.card {
  background-color: var(--card-bg);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  padding: 1.75rem;
  transition: transform 0.2s ease, border-color 0.2s ease;
}

.card:hover {
  transform: translateY(-4px);
  border-color: var(--accent-cyan);
}

.card h3 {
  color: var(--accent-cyan);
  margin-bottom: 0.75rem;
  font-size: 1.25rem;
}

.card p {
  color: var(--text-muted);
  font-size: 0.95rem;
}

article.content-block {
  background-color: var(--card-bg);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  padding: 2rem;
  margin-bottom: 2rem;
}

article.content-block h2 {
  color: var(--accent-cyan);
  margin-bottom: 1rem;
  font-size: 1.75rem;
}

article.content-block p {
  margin-bottom: 1rem;
  color: var(--text-muted);
}

article.content-block ul {
  margin-left: 1.5rem;
  margin-bottom: 1rem;
  color: var(--text-muted);
}

article.content-block li {
  margin-bottom: 0.5rem;
}

.interactive-demo {
  background-color: var(--card-bg);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  padding: 2rem;
  text-align: center;
  margin-top: 2rem;
}

.interactive-demo h2 {
  color: var(--accent-indigo);
  margin-bottom: 1rem;
}

.demo-controls {
  display: flex;
  justify-content: center;
  gap: 1rem;
  margin: 1.5rem 0;
}

.btn {
  background-color: #334155;
  color: var(--text-main);
  border: 1px solid var(--accent-cyan);
  padding: 0.6rem 1.2rem;
  border-radius: 6px;
  cursor: pointer;
  font-weight: 600;
  transition: background-color 0.2s ease;
}

.btn:hover {
  background-color: var(--accent-cyan);
  color: var(--bg-color);
}

.status-display {
  font-size: 1.1rem;
  padding: 1rem;
  background-color: var(--bg-color);
  border-radius: 6px;
  border: 1px dashed var(--border-color);
  display: inline-block;
  min-width: 280px;
}

footer {
  background-color: var(--card-bg);
  border-top: 1px solid var(--border-color);
  text-align: center;
  padding: 1.5rem;
  color: var(--text-muted);
  font-size: 0.9rem;
}

@media (max-width: 640px) {
  .nav-container {
    flex-direction: column;
    gap: 1rem;
  }
  .hero h1 {
    font-size: 2rem;
  }
}