:root {
  --primary-color: #e2136e;
  --primary-dark: #c5115d;
  --primary-light: #ff6a88;
  --secondary-color: #2c3e50;
  --text-dark: #333;
  --text-light: #666;
  --bg-light: #f9f9f9;
  --bg-white: #fff;
  --shadow-sm: 0 2px 4px rgba(0,0,0,0.1);
  --shadow-md: 0 4px 8px rgba(0,0,0,0.15);
  --shadow-lg: 0 8px 16px rgba(0,0,0,0.2);
  --border-radius: 8px;
  --transition: all 0.3s ease;
}

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

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
  color: var(--text-dark);
  line-height: 1.6;
  background-color: var(--bg-light);
  scroll-behavior: smooth;
}

.nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 20px 40px;
  background: var(--bg-white);
  box-shadow: var(--shadow-sm);
  position: sticky;
  top: 0;
  z-index: 1000;
  transition: var(--transition);
}

.nav-logo {
  font-weight: bold;
  font-size: 1.5rem;
  color: var(--primary-color);
  display: flex;
  align-items: center;
  gap: 8px;
  transition: var(--transition);
  cursor: pointer;
}

.nav-logo:hover {
  transform: scale(1.05);
}

.nav-links {
  list-style: none;
  display: flex;
  gap: 30px;
  margin: 0;
  padding: 0;
  align-items: center;
}

.nav-links a {
  text-decoration: none;
  color: var(--text-dark);
  font-weight: 500;
  transition: var(--transition);
  padding: 8px 16px;
  border-radius: 4px;
  position: relative;
}

.nav-links a:hover {
  color: var(--primary-color);
  background-color: rgba(226, 19, 110, 0.1);
}

.nav-links a.active {
  color: var(--primary-color);
  font-weight: 600;
}

.github-link {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  background: var(--secondary-color);
  color: var(--bg-white) !important;
  padding: 8px 16px !important;
  border-radius: 6px;
  font-weight: 500;
  transition: var(--transition);
}

.github-link:hover {
  background: #1a252f !important;
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

.hero {
  text-align: center;
  padding: 120px 20px 100px;
  background: linear-gradient(135deg, var(--primary-color), var(--primary-light));
  color: var(--bg-white);
  position: relative;
  overflow: hidden;
}

.hero::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: url('data:image/svg+xml,<svg width="100" height="100" xmlns="http://www.w3.org/2000/svg"><circle cx="50" cy="50" r="2" fill="white" opacity="0.1"/></svg>');
  opacity: 0.3;
}

.hero h1 {
  font-size: 3rem;
  margin-bottom: 20px;
  position: relative;
  z-index: 1;
  animation: fadeInUp 0.8s ease;
}

.hero p {
  font-size: 1.3rem;
  margin-bottom: 30px;
  position: relative;
  z-index: 1;
  opacity: 0.95;
  animation: fadeInUp 1s ease;
}

@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(30px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.btn-primary {
  display: inline-block;
  margin-top: 20px;
  padding: 14px 32px;
  background: var(--bg-white);
  color: var(--primary-color);
  text-decoration: none;
  border-radius: 6px;
  font-weight: 600;
  font-size: 1.1rem;
  transition: var(--transition);
  box-shadow: var(--shadow-md);
  position: relative;
  z-index: 1;
}

.btn-primary:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-lg);
  background: #fafafa;
}

.features {
  max-width: 1200px;
  margin: 80px auto;
  padding: 0 40px;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 30px;
}

.feature-card {
  background: var(--bg-white);
  padding: 30px;
  border-radius: var(--border-radius);
  box-shadow: var(--shadow-sm);
  transition: var(--transition);
  border-top: 4px solid var(--primary-color);
}

.feature-card:hover {
  transform: translateY(-5px);
  box-shadow: var(--shadow-lg);
}

.feature-card h3 {
  color: var(--primary-color);
  margin-bottom: 15px;
  font-size: 1.4rem;
}

.feature-card p {
  color: var(--text-light);
  font-size: 1rem;
  line-height: 1.8;
}

.demo {
  max-width: 900px;
  margin: 80px auto;
  padding: 40px;
  background: var(--bg-white);
  border-radius: var(--border-radius);
  box-shadow: var(--shadow-md);
}

.demo h2 {
  text-align: center;
  color: var(--secondary-color);
  margin-bottom: 40px;
  font-size: 2rem;
}

.demo input {
  padding: 10px;
  margin-right: 10px;
  border: 2px solid #ddd;
  border-radius: 4px;
  transition: var(--transition);
}

.demo input:focus {
  outline: none;
  border-color: var(--primary-color);
}

.product-card {
  background: linear-gradient(135deg, #f8f9fa 0%, #e9ecef 100%);
  padding: 40px;
  border-radius: var(--border-radius);
  box-shadow: var(--shadow-sm);
  text-align: center;
  max-width: 400px;
  margin: 0 auto;
  border: 2px solid #dee2e6;
}

.product-card h3 {
  font-size: 1.8rem;
  color: var(--secondary-color);
  margin-bottom: 15px;
}

.product-card p {
  font-size: 1.3rem;
  color: var(--text-dark);
  margin: 20px 0;
  font-weight: 600;
}

#status {
  margin-top: 15px;
  padding: 10px;
  border-radius: 4px;
  font-weight: 500;
}

.footer {
  text-align: center;
  padding: 30px 20px;
  background: var(--secondary-color);
  color: var(--bg-white);
  margin-top: 80px;
}

.footer p {
  margin: 0;
  opacity: 0.9;
}

.content {
  max-width: 900px;
  margin: 60px auto;
  padding: 40px;
  background: var(--bg-white);
  border-radius: var(--border-radius);
  box-shadow: var(--shadow-sm);
}

.content h1 {
  color: var(--secondary-color);
  margin-bottom: 30px;
  font-size: 2.5rem;
  border-bottom: 3px solid var(--primary-color);
  padding-bottom: 15px;
}

.content h2 {
  color: var(--primary-color);
  margin-top: 40px;
  margin-bottom: 20px;
  font-size: 1.8rem;
}

.content h3 {
  color: var(--secondary-color);
  margin-top: 30px;
  margin-bottom: 15px;
  font-size: 1.4rem;
}

.content ol, .content ul {
  margin-left: 25px;
  margin-bottom: 20px;
}

.content li {
  margin-bottom: 12px;
  line-height: 1.8;
}

.content p {
  margin-bottom: 20px;
  color: var(--text-light);
  line-height: 1.8;
}

pre {
  background: #2c3e50;
  color: #ecf0f1;
  padding: 20px;
  overflow-x: auto;
  border-radius: var(--border-radius);
  margin: 20px 0;
  box-shadow: var(--shadow-sm);
  border-left: 4px solid var(--primary-color);
}

code {
  font-family: 'Consolas', 'Monaco', 'Courier New', monospace;
  font-size: 0.9rem;
  background: #f4f4f4;
  padding: 2px 6px;
  border-radius: 3px;
  color: var(--primary-color);
}

pre code {
  background: transparent;
  padding: 0;
  color: #ecf0f1;
}

.bkash-pay-button {
  background: var(--primary-color);
  color: var(--bg-white);
  border: none;
  padding: 14px 30px;
  border-radius: 6px;
  cursor: pointer;
  font-size: 1.1rem;
  font-weight: 600;
  transition: var(--transition);
  box-shadow: var(--shadow-sm);
  margin-top: 10px;
}

.bkash-pay-button:hover {
  background: var(--primary-dark);
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

.bkash-pay-button:active {
  transform: translateY(0);
}

.bkash-modal {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: rgba(0, 0, 0, 0.7);
  display: flex;
  align-items: center;
  justify-content: center;
  visibility: hidden;
  opacity: 0;
  transition: var(--transition);
  z-index: 2000;
}

.bkash-modal.active {
  visibility: visible;
  opacity: 1;
}

.bkash-modal-content {
  background: var(--bg-white);
  padding: 30px;
  border-radius: var(--border-radius);
  width: 90%;
  max-width: 400px;
  text-align: center;
  box-shadow: var(--shadow-lg);
  transform: scale(0.9);
  transition: var(--transition);
}

.bkash-modal.active .bkash-modal-content {
  transform: scale(1);
}

.bkash-modal-content input {
  width: 100%;
  padding: 12px;
  margin-bottom: 15px;
  border: 2px solid #ddd;
  border-radius: 4px;
  font-size: 1rem;
  transition: var(--transition);
}

.bkash-modal-content input:focus {
  outline: none;
  border-color: var(--primary-color);
}

/* Responsive Design */
@media (max-width: 768px) {
  .nav {
    padding: 15px 20px;
    flex-wrap: wrap;
  }

  .nav-logo {
    font-size: 1.2rem;
  }

  .nav-links {
    gap: 15px;
    flex-wrap: wrap;
  }

  .nav-links a {
    padding: 6px 12px;
    font-size: 0.9rem;
  }

  .hero {
    padding: 80px 20px 60px;
  }

  .hero h1 {
    font-size: 2rem;
  }

  .hero p {
    font-size: 1rem;
  }

  .features {
    padding: 0 20px;
    gap: 20px;
    margin: 50px auto;
  }

  .demo {
    padding: 30px 20px;
    margin: 50px auto;
  }

  .content {
    padding: 30px 20px;
    margin: 40px auto;
  }

  .content h1 {
    font-size: 2rem;
  }

  .content h2 {
    font-size: 1.5rem;
  }

  pre {
    padding: 15px;
    font-size: 0.85rem;
  }
}

@media (max-width: 480px) {
  .hero h1 {
    font-size: 1.5rem;
  }

  .btn-primary {
    padding: 12px 24px;
    font-size: 1rem;
  }

  .features {
    grid-template-columns: 1fr;
  }

  .product-card {
    padding: 25px;
  }
}