:root {
  --bg-primary: #0f172a; /* Slate 900 */
  --bg-secondary: #1e293b; /* Slate 800 */
  --bg-glass: rgba(30, 41, 59, 0.7);
  --text-primary: #f8fafc; /* Slate 50 */
  --text-secondary: #94a3b8; /* Slate 400 */
  --accent-base: #3b82f6; /* Blue 500 */
  --accent-glow: rgba(59, 130, 246, 0.5);
  --gradient-accent: linear-gradient(135deg, #3b82f6, #8b5cf6); /* Blue to Purple */
  
  --font-main: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  --transition-normal: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  --radius-md: 12px;
  --radius-lg: 20px;
}

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

body {
  font-family: var(--font-main);
  background-color: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  overflow-x: hidden;
  background-image: 
    radial-gradient(at 0% 0%, rgba(59, 130, 246, 0.15) 0vw, transparent 50vw),
    radial-gradient(at 100% 100%, rgba(139, 92, 246, 0.1) 0vw, transparent 50vw);
  background-attachment: fixed;
}

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

a:hover {
  color: var(--accent-base);
}

ul {
  list-style: none;
}

/* Layout */
.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 2rem;
}

section {
  padding: 6rem 0;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
  font-weight: 700;
  line-height: 1.2;
  margin-bottom: 1rem;
}

h1 {
  font-size: clamp(2.5rem, 5vw, 4rem);
  background: var(--gradient-accent);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

h2 {
  font-size: 2.5rem;
  margin-bottom: 3rem;
  text-align: center;
}

.text-gradient {
  background: var(--gradient-accent);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

/* Navigation */
header {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  z-index: 1000;
  background: rgba(15, 23, 42, 0.8);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid rgba(255, 255, 255, 0.05);
  transition: all var(--transition-normal);
}

header.scrolled {
  box-shadow: 0 4px 30px rgba(0, 0, 0, 0.5);
  padding: 0.5rem 0;
}

nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
  height: 80px;
}

.logo {
  font-size: 1.5rem;
  font-weight: 800;
  letter-spacing: -0.5px;
}

.nav-links {
  display: flex;
  gap: 2.5rem;
}

.nav-links a {
  font-size: 0.95rem;
  font-weight: 500;
  position: relative;
  padding: 0.5rem 0;
}

.nav-links a::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--gradient-accent);
  transition: width var(--transition-normal);
}

.nav-links a:hover::after,
.nav-links a.active::after {
  width: 100%;
}

.mobile-menu-btn {
  display: none;
  background: none;
  border: none;
  color: var(--text-primary);
  font-size: 1.5rem;
  cursor: pointer;
}

/* Buttons */
.btn {
  display: inline-block;
  padding: 0.8rem 2rem;
  border-radius: 30px;
  font-weight: 600;
  font-size: 1rem;
  cursor: pointer;
  transition: all var(--transition-normal);
  border: none;
}

.btn-primary {
  background: var(--gradient-accent);
  color: white;
  box-shadow: 0 4px 15px var(--accent-glow);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(139, 92, 246, 0.6);
  color: white;
}

.btn-outline {
  background: transparent;
  border: 2px solid var(--accent-base);
  color: var(--accent-base);
}

.btn-outline:hover {
  background: var(--accent-base);
  color: white;
  transform: translateY(-2px);
}

/* Cards (Glassmorphism) */
.glass-card {
  background: var(--bg-glass);
  backdrop-filter: blur(10px);
  border: 1px solid rgba(255, 255, 255, 0.05);
  border-radius: var(--radius-lg);
  padding: 2rem;
  transition: transform var(--transition-normal), box-shadow var(--transition-normal);
}

.glass-card:hover {
  transform: translateY(-5px);
  border-color: rgba(255, 255, 255, 0.1);
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.3);
}

/* Footer */
footer {
  background: var(--bg-secondary);
  padding: 3rem 0;
  text-align: center;
  border-top: 1px solid rgba(255, 255, 255, 0.05);
  margin-top: 4rem;
}

.social-links {
  display: flex;
  justify-content: center;
  gap: 1.5rem;
  margin-bottom: 1.5rem;
}

.social-links a {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.05);
  transition: all var(--transition-normal);
}

.social-links a:hover {
  background: var(--gradient-accent);
  color: white;
  transform: translateY(-3px);
}

/* Animations */
.reveal {
  opacity: 0;
  transform: translateY(30px);
  transition: all 0.8s cubic-bezier(0.5, 0, 0, 1);
}

.reveal.active {
  opacity: 1;
  transform: translateY(0);
}

.delay-1 { transition-delay: 0.1s; }
.delay-2 { transition-delay: 0.2s; }
.delay-3 { transition-delay: 0.3s; }

/* Responsive Grid Helper */
.grid {
  display: grid;
  gap: 2rem;
}

@media (min-width: 768px) {
  .grid-2 { grid-template-columns: repeat(2, 1fr); }
  .grid-3 { grid-template-columns: repeat(3, 1fr); }
}

/* Mobile Responsive */
@media (max-width: 768px) {
  .mobile-menu-btn {
    display: block;
  }
  
  .nav-links {
    position: fixed;
    top: 80px;
    left: -100%;
    width: 100%;
    height: calc(100vh - 80px);
    background: var(--bg-primary);
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 2rem;
    transition: left 0.4s ease;
  }
  
  .nav-links.nav-active {
    left: 0;
  }
  
  .nav-links a {
    font-size: 1.5rem;
  }
}