:root {
  --bg-color: #0b0f19;
  --surface-color: rgba(255, 255, 255, 0.03);
  --surface-border: rgba(255, 255, 255, 0.08);
  --text-primary: #f8fafc;
  --text-secondary: #94a3b8;
  --accent-color: #0ea5e9;
  --accent-glow: rgba(14, 165, 233, 0.4);
  --pcb-green: #10b981;
  --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  --font-main: 'Inter', sans-serif;
}

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

body {
  font-family: var(--font-main);
  background-color: var(--bg-color);
  color: var(--text-primary);
  line-height: 1.6;
  overflow-x: hidden;
  background-image: radial-gradient(circle at 50% 0%, rgba(14, 165, 233, 0.1) 0%, transparent 50%);
  background-attachment: fixed;
}

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

h1 {
  font-size: 3.5rem;
  background: linear-gradient(to right, #fff, var(--text-secondary));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

h2 {
  font-size: 2.5rem;
  margin-bottom: 2rem;
  position: relative;
  display: inline-block;
}

h2::after {
  content: '';
  position: absolute;
  bottom: -10px;
  left: 0;
  width: 50%;
  height: 3px;
  background: var(--accent-color);
  border-radius: 2px;
  box-shadow: 0 0 10px var(--accent-glow);
}

p {
  color: var(--text-secondary);
  margin-bottom: 1rem;
}

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

a:hover {
  text-shadow: 0 0 8px var(--accent-glow);
}

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

section {
  padding: 6rem 0;
}

/* Header & Nav */
header {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  z-index: 1000;
  background: rgba(11, 15, 25, 0.8);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--surface-border);
  transition: var(--transition);
}

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

.logo {
  font-size: 1.5rem;
  font-weight: 800;
  letter-spacing: 1px;
  color: var(--text-primary);
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.logo span {
  color: var(--accent-color);
}

.nav-links {
  display: flex;
  gap: 2.5rem;
  list-style: none;
}

.nav-links a {
  color: var(--text-secondary);
  font-weight: 500;
  font-size: 0.95rem;
  text-transform: uppercase;
  letter-spacing: 1px;
  position: relative;
}

.nav-links a::after {
  content: '';
  position: absolute;
  bottom: -5px;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--accent-color);
  transition: var(--transition);
}

.nav-links a:hover,
.nav-links a.active {
  color: var(--text-primary);
}

.nav-links a:hover::after,
.nav-links a.active::after {
  width: 100%;
  box-shadow: 0 0 8px var(--accent-glow);
}

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

/* Glassmorphism Cards */
.glass-card {
  background: var(--surface-color);
  border: 1px solid var(--surface-border);
  border-radius: 16px;
  padding: 2.5rem;
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  transition: var(--transition);
  position: relative;
  overflow: hidden;
}

.glass-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 1px;
  background: linear-gradient(90deg, transparent, rgba(255,255,255,0.2), transparent);
  transform: translateX(-100%);
  transition: 0.5s;
}

.glass-card:hover {
  transform: translateY(-5px);
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.5);
  border-color: rgba(255, 255, 255, 0.15);
}

.glass-card:hover::before {
  transform: translateX(100%);
}

/* Buttons */
.btn {
  display: inline-block;
  padding: 0.8rem 2rem;
  border-radius: 8px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 1px;
  cursor: pointer;
  transition: var(--transition);
  border: none;
  font-size: 0.9rem;
}

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

.btn-primary:hover {
  background: #0284c7;
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(14, 165, 233, 0.6);
  color: #fff;
}

.btn-outline {
  background: transparent;
  color: var(--accent-color);
  border: 1px solid var(--accent-color);
}

.btn-outline:hover {
  background: rgba(14, 165, 233, 0.1);
  box-shadow: 0 0 15px var(--accent-glow);
  transform: translateY(-2px);
}

/* Footer */
footer {
  border-top: 1px solid var(--surface-border);
  padding: 3rem 0;
  text-align: center;
  background: rgba(11, 15, 25, 0.95);
  margin-top: 4rem;
}

footer p {
  margin: 0;
  font-size: 0.9rem;
}

/* Scrollbar */
::-webkit-scrollbar {
  width: 10px;
}

::-webkit-scrollbar-track {
  background: var(--bg-color);
}

::-webkit-scrollbar-thumb {
  background: var(--surface-border);
  border-radius: 5px;
}

::-webkit-scrollbar-thumb:hover {
  background: var(--accent-color);
}

/* Animations */
.fade-in {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.8s ease-out, transform 0.8s ease-out;
}

.fade-in.visible {
  opacity: 1;
  transform: translateY(0);
}

/* Grid Layouts */
.grid-2 {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 2rem;
}

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

/* Utilities */
.text-center { text-align: center; }
.mt-2 { margin-top: 2rem; }
.mb-2 { margin-bottom: 2rem; }
.pt-6 { padding-top: 6rem; }

/* Responsive */
@media (max-width: 768px) {
  h1 { font-size: 2.5rem; }
  h2 { font-size: 2rem; }
  
  .grid-2 { grid-template-columns: 1fr; }
  
  .mobile-menu-btn { display: block; }
  
  .nav-links {
    position: fixed;
    top: 80px;
    left: -100%;
    width: 100%;
    height: calc(100vh - 80px);
    background: rgba(11, 15, 25, 0.98);
    flex-direction: column;
    align-items: center;
    justify-content: center;
    transition: var(--transition);
    backdrop-filter: blur(15px);
  }
  
  .nav-links.active {
    left: 0;
  }
  
  .nav-links li { margin: 1.5rem 0; }
  .nav-links a { font-size: 1.2rem; }
}