:root {
  /* Brand Colors */
  --primary: #2563eb;       /* Electric Blue */
  --primary-dark: #1e40af;  /* Deep Blue */
  --accent: #06b6d4;        /* Cyan/Teal for AI feel */
  --accent-light: #e0f2fe;
  
  /* Neutrals */
  --text-main: #111827;     /* Almost Black */
  --text-light: #4b5563;    /* Dark Gray */
  --text-lighter: #9ca3af;  /* Light Gray */
  --white: #ffffff;
  --bg-light: #f9fafb;      /* Very Light Gray */
  --bg-white: #ffffff;
  --bg-dark: #0f172a;       /* Slate 900 */
  
  /* Borders */
  --border: #e5e7eb;
  
  /* Spacing */
  --container-width: 1280px;
  --header-height: 80px;
  
  /* Radius */
  --radius-sm: 6px;
  --radius-md: 12px;
  --radius-lg: 20px;
  --radius-full: 9999px;
  
  /* Shadows */
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
  --shadow-hover: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
}

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

body {
  font-family: 'Inter', system-ui, -apple-system, sans-serif;
  color: var(--text-main);
  background-color: var(--bg-white);
  line-height: 1.6;
  overflow-x: hidden;
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

h1, h2, h3, h4, h5, h6 {
  line-height: 1.2;
  font-weight: 700;
  color: var(--text-main);
  margin-bottom: 1rem;
}

h1 { font-size: 3.5rem; letter-spacing: -0.02em; }
h2 { font-size: 2.5rem; letter-spacing: -0.02em; }
h3 { font-size: 1.5rem; }
p { margin-bottom: 1.5rem; color: var(--text-light); }

a { text-decoration: none; color: inherit; transition: all 0.2s; }
ul { list-style: none; }
img { max-width: 100%; display: block; }

/* Utilities */
.container {
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 0 24px;
  width: 100%;
}

.text-center { text-align: center; }
.text-primary { color: var(--primary); }
.text-accent { color: var(--accent); }
.text-white { color: var(--white); }

.bg-light { background-color: var(--bg-light); }
.bg-dark { background-color: var(--bg-dark); color: var(--white); }
.bg-primary { background-color: var(--primary); color: var(--white); }

.py-lg { padding-top: 80px; padding-bottom: 80px; }
.py-md { padding-top: 48px; padding-bottom: 48px; }

.mb-sm { margin-bottom: 16px; }
.mb-md { margin-bottom: 32px; }
.mb-lg { margin-bottom: 64px; }

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 14px 28px;
  border-radius: var(--radius-md);
  font-weight: 600;
  cursor: pointer;
  border: none;
  font-size: 1rem;
  transition: all 0.3s ease;
  white-space: nowrap;
}

.btn-primary {
  background: linear-gradient(135deg, var(--primary) 0%, #4f46e5 100%);
  color: white;
  box-shadow: 0 4px 14px rgba(37, 99, 235, 0.4);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 20px rgba(37, 99, 235, 0.5);
}

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

.btn-outline:hover {
  background: var(--primary);
  color: white;
}

.btn-white {
  background: white;
  color: var(--primary);
}
.btn-white:hover {
  background: #f0f9ff;
}

.btn-sm { padding: 10px 20px; font-size: 0.9rem; }

/* Navbar */
.navbar {
  height: var(--header-height);
  background: rgba(255, 255, 255, 0.9);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 1000;
}

.nav-container {
  height: 100%;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.logo {
  font-size: 1.5rem;
  font-weight: 800;
  color: var(--text-main);
  display: flex;
  align-items: center;
  gap: 8px;
}

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

.nav-links {
  display: flex;
  gap: 32px;
}

.nav-link {
  font-weight: 500;
  font-size: 1rem;
  color: var(--text-light);
  position: relative;
}

.nav-link:hover, .nav-link.active {
  color: var(--primary);
}

.nav-link::after {
  content: '';
  position: absolute;
  width: 0;
  height: 2px;
  bottom: -4px;
  left: 0;
  background-color: var(--primary);
  transition: width 0.3s;
}

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

/* Hero Section */
.hero {
  padding: 120px 0 80px;
  background: 
    radial-gradient(circle at 10% 20%, rgba(37, 99, 235, 0.05) 0%, transparent 50%),
    radial-gradient(circle at 90% 80%, rgba(6, 182, 212, 0.05) 0%, transparent 50%);
  position: relative;
  overflow: hidden;
}

.hero-content {
  max-width: 800px;
  position: relative;
  z-index: 2;
}

.badge {
  display: inline-block;
  padding: 6px 16px;
  border-radius: var(--radius-full);
  font-size: 0.875rem;
  font-weight: 600;
  background: var(--accent-light);
  color: var(--primary-dark);
  margin-bottom: 24px;
}

.badge-primary {
  background: rgba(37, 99, 235, 0.1);
  color: var(--primary);
}

/* Cards & Grid */
.grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 32px;
}

.grid-2 {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 64px;
}

.card {
  background: var(--white);
  border-radius: var(--radius-lg);
  padding: 32px;
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--border);
  transition: all 0.3s ease;
  height: 100%;
  display: flex;
  flex-direction: column;
  position: relative;
  overflow: hidden;
}

.card:hover {
  transform: translateY(-8px);
  box-shadow: var(--shadow-hover);
  border-color: var(--accent);
}

.card-icon {
  width: 56px;
  height: 56px;
  background: var(--bg-light);
  color: var(--primary);
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.75rem;
  margin-bottom: 24px;
}

/* Course Card Specifics */
.course-header {
  margin-bottom: 16px;
}

.course-tags {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  margin-bottom: 20px;
}

.tag {
  font-size: 0.75rem;
  padding: 4px 10px;
  background: var(--bg-light);
  border-radius: 4px;
  color: var(--text-light);
  font-weight: 500;
}

/* Forms */
.form-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 20px;
  max-width: 600px;
  margin: 0 auto;
}

.form-group label {
  display: block;
  margin-bottom: 8px;
  font-weight: 500;
  color: var(--text-main);
}

.form-input, .form-textarea {
  width: 100%;
  padding: 14px;
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  font-size: 1rem;
  font-family: inherit;
  transition: all 0.2s;
  background: var(--bg-light);
}

.form-input:focus, .form-textarea:focus {
  outline: none;
  border-color: var(--primary);
  background: var(--white);
  box-shadow: 0 0 0 4px rgba(37, 99, 235, 0.1);
}

.form-textarea { min-height: 120px; resize: vertical; }

/* Stats */
.stats-container {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 40px;
  text-align: center;
  margin-top: 40px;
}

.stat-number {
  font-size: 3rem;
  font-weight: 800;
  color: var(--primary);
  line-height: 1;
  margin-bottom: 8px;
}

.stat-label {
  font-size: 1.1rem;
  color: var(--text-light);
}

/* Footer */
footer {
  background: var(--bg-dark);
  color: var(--white);
  padding: 80px 0 40px;
  margin-top: auto;
}

.footer-content {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 48px;
  margin-bottom: 48px;
}

.footer-col h4 {
  color: var(--white);
  font-size: 1.25rem;
  margin-bottom: 24px;
}

.footer-col ul li {
  margin-bottom: 12px;
}

.footer-col a {
  color: var(--text-lighter);
}

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

.copyright {
  border-top: 1px solid rgba(255,255,255,0.1);
  padding-top: 32px;
  text-align: center;
  color: var(--text-lighter);
  font-size: 0.9rem;
}

/* Placeholders */
.placeholder-image {
  width: 100%;
  height: 200px;
  background-color: #e5e7eb;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-md);
  margin-bottom: 24px;
  color: #6b7280;
  font-weight: 500;
}

/* Responsive */
@media (max-width: 1024px) {
  .container { max-width: 960px; }
  h1 { font-size: 3rem; }
}

@media (max-width: 768px) {
  .container { max-width: 100%; }
  
  .navbar { height: auto; padding: 16px 0; }
  .nav-container { flex-direction: column; gap: 20px; }
  .nav-links { flex-wrap: wrap; justify-content: center; gap: 16px; }
  
  h1 { font-size: 2.25rem; }
  h2 { font-size: 1.75rem; }
  
  .hero { text-align: center; padding: 60px 0; }
  .hero-content { margin: 0 auto; }
  .btn { width: 100%; margin-bottom: 8px; }
  .grid-2 { grid-template-columns: 1fr; gap: 32px; }
}