:root {
  --color-bg-primary: #0a192f;
  --color-bg-secondary: #112240;
  --color-bg-tertiary: #233554;
  --color-text-primary: #ccd6f6;
  --color-text-secondary: #8892b0;
  --color-accent: #64ffda;
  --color-white: #e6f1ff;
  --color-error: #ff6b6b;

  --font-sans: 'Inter', system-ui, -apple-system, sans-serif;
  --font-mono: 'Fira Code', monospace;

  --transition-default: 0.3s cubic-bezier(0.645, 0.045, 0.355, 1);
}

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

html {
  font-family: var(--font-sans);
  background-color: var(--color-bg-primary);
  color: var(--color-text-primary);
  line-height: 1.6;
  scroll-behavior: smooth;
}

a {
  text-decoration: none;
  color: inherit;
  transition: var(--transition-default);
}

ul {
  list-style: none;
}

button {
  cursor: pointer;
  border: none;
  background: none;
  font-family: inherit;
}

/* Utilities */
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 2rem;
}

.btn {
  display: inline-block;
  padding: 0.75rem 1.5rem;
  border-radius: 4px;
  font-weight: 500;
  border: 1px solid var(--color-accent);
  color: var(--color-accent);
  transition: var(--transition-default);
}

.btn:hover {
  background-color: rgba(100, 255, 218, 0.1);
}

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

.btn-primary:hover {
  background-color: rgba(100, 255, 218, 0.8);
}

/* Header */
header {
  position: fixed;
  top: 0;
  width: 100%;
  background-color: rgba(10, 25, 47, 0.85);
  backdrop-filter: blur(10px);
  z-index: 1000;
  padding: 1rem 0;
  border-bottom: 1px solid rgba(255, 255, 255, 0.05);
}

nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.logo {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--color-accent);
  letter-spacing: -1px;
}

.nav-links {
  display: flex;
  gap: 2rem;
}

.nav-links a {
  font-size: 0.9rem;
  font-weight: 500;
  position: relative;
}

.nav-links a:hover {
  color: var(--color-accent);
}

/* Hero Section */
.hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  padding-top: 80px;
}

.hero-content {
  max-width: 800px;
}

.hero h1 {
  font-size: 4rem;
  line-height: 1.1;
  color: var(--color-white);
  margin-bottom: 1.5rem;
}

.hero p {
  font-size: 1.25rem;
  color: var(--color-text-secondary);
  margin-bottom: 2rem;
  max-width: 600px;
}

/* Cards */
.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 2rem;
  margin: 4rem 0;
}

.card {
  background-color: var(--color-bg-secondary);
  padding: 2rem;
  border-radius: 8px;
  transition: var(--transition-default);
  border: 1px solid transparent;
}

.card:hover {
  transform: translateY(-5px);
  border-color: var(--color-accent);
}

.card h3 {
  color: var(--color-white);
  margin-bottom: 1rem;
}

/* Footer */
footer {
  background-color: var(--color-bg-secondary);
  padding: 4rem 0 2rem;
  margin-top: 6rem;
  border-top: 1px solid rgba(255, 255, 255, 0.05);
}

.footer-content {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 4rem;
  margin-bottom: 3rem;
}

.footer-col h4 {
  color: var(--color-white);
  margin-bottom: 1.5rem;
  font-size: 1.1rem;
}

.footer-col ul li {
  margin-bottom: 0.75rem;
}

.footer-col a {
  color: var(--color-text-secondary);
  font-size: 0.9rem;
}

.footer-col a:hover {
  color: var(--color-accent);
}

.footer-bottom {
  text-align: center;
  padding-top: 2rem;
  border-top: 1px solid rgba(255, 255, 255, 0.05);
  color: var(--color-text-secondary);
  font-size: 0.85rem;
}

@media (max-width: 768px) {
  .footer-content {
    grid-template-columns: 1fr;
    gap: 2rem;
  }
}

/* Responsive */
@media (max-width: 768px) {
  .hero h1 {
    font-size: 3rem;
  }

  .nav-links {
    display: none;
    /* simple hide for now, would generally implement burger menu */
  }
}