/* Reset & Base */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: var(--font-primary);
  font-size: var(--text-base);
  line-height: 1.6;
  color: var(--text-dark);
  background-color: var(--white);
}

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

@media (min-width: 768px) {
  .container {
    padding: 0 var(--container-tablet);
  }
}

@media (min-width: 1024px) {
  .container {
    padding: 0 var(--container-desktop);
  }
}

/* Navigation */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(10px);
  z-index: var(--z-fixed);
  border-bottom: 1px solid var(--border-light);
  transition: var(--transition-normal);
}

.navbar.scrolled {
  background: rgba(255, 255, 255, 0.98);
  box-shadow: var(--shadow-md);
}

.nav-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--spacing-md) var(--container-mobile);
  min-height: 60px;
}

.nav-logo {
  height: 35px;
  width: auto;
}

.nav-menu {
  display: none;
  list-style: none;
  gap: var(--spacing-xl);
}

.nav-menu.active {
  display: flex;
  position: absolute;
  top: 100%;
  left: 0;
  right: 0;
  flex-direction: column;
  background: var(--white);
  padding: var(--spacing-lg);
  box-shadow: var(--shadow-lg);
  gap: var(--spacing-md);
}

.nav-link {
  text-decoration: none;
  color: var(--text-dark);
  font-weight: 500;
  font-size: var(--text-sm);
  transition: var(--transition-fast);
  padding: var(--spacing-sm) 0;
}

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

.nav-toggle {
  display: flex;
  flex-direction: column;
  cursor: pointer;
  gap: 3px;
  background: none;
  border: none;
  padding: var(--spacing-sm);
}

.nav-toggle span {
  width: 20px;
  height: 2px;
  background: var(--text-dark);
  transition: var(--transition-fast);
}

.nav-toggle.active span:nth-child(1) {
  transform: rotate(45deg) translate(5px, 5px);
}

.nav-toggle.active span:nth-child(2) {
  opacity: 0;
}

.nav-toggle.active span:nth-child(3) {
  transform: rotate(-45deg) translate(7px, -6px);
}

@media (min-width: 768px) {
  .nav-container {
    padding: var(--spacing-lg) var(--container-tablet);
    min-height: 70px;
  }
  
  .nav-logo {
    height: 42px;
  }
  
  .nav-menu {
    display: flex;
    position: static;
    flex-direction: row;
    background: transparent;
    padding: 0;
    box-shadow: none;
  }
  
  .nav-toggle {
    display: none;
  }
  
  .nav-link {
    font-size: var(--text-base);
    padding: var(--spacing-sm) var(--spacing-md);
    border-radius: var(--radius-sm);
  }
  
  .nav-link:hover {
    background: rgba(46, 91, 186, 0.1);
  }
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: var(--spacing-md) var(--spacing-xl);
  font-size: var(--text-sm);
  font-weight: 600;
  text-decoration: none;
  border: none;
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: var(--transition-normal);
  gap: var(--spacing-sm);
  min-height: 44px;
}

.btn-primary {
  background: var(--gradient-primary);
  color: var(--white);
  box-shadow: var(--shadow-md);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
}

.btn-secondary {
  background: var(--gradient-accent);
  color: var(--white);
  box-shadow: var(--shadow-md);
}

.btn-secondary:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
}

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

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

.btn-lg {
  padding: var(--spacing-lg) var(--spacing-2xl);
  font-size: var(--text-lg);
}

@media (min-width: 768px) {
  .btn {
    padding: var(--spacing-lg) var(--spacing-2xl);
    font-size: var(--text-base);
  }
}

/* Cards */
.card {
  background: var(--white);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-md);
  overflow: hidden;
  transition: var(--transition-normal);
}

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

.card-image {
  width: 100%;
  height: 180px;
  object-fit: cover;
}

.card-content {
  padding: var(--spacing-lg);
}

.card-title {
  font-family: var(--font-heading);
  font-size: var(--text-lg);
  font-weight: 600;
  color: var(--text-dark);
  margin-bottom: var(--spacing-sm);
  line-height: 1.3;
}

.card-subtitle {
  font-size: var(--text-sm);
  color: var(--primary-blue);
  font-weight: 500;
  margin-bottom: var(--spacing-md);
}

.card-text {
  font-size: var(--text-sm);
  color: var(--text-light);
  margin-bottom: var(--spacing-lg);
  line-height: 1.5;
}

.card-meta {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: var(--spacing-lg);
  gap: var(--spacing-md);
}

.card-price {
  font-size: var(--text-lg);
  font-weight: 700;
  color: var(--primary-orange);
}

.card-duration {
  font-size: var(--text-sm);
  color: var(--text-light);
  background: var(--light-gray);
  padding: var(--spacing-xs) var(--spacing-sm);
  border-radius: var(--radius-sm);
}

@media (min-width: 768px) {
  .card-image {
    height: 220px;
  }
  
  .card-content {
    padding: var(--spacing-xl);
  }
}

/* Grid System */
.grid {
  display: grid;
  gap: var(--spacing-lg);
}

.grid-1 { grid-template-columns: 1fr; }
.grid-2 { grid-template-columns: repeat(2, 1fr); }
.grid-3 { grid-template-columns: repeat(3, 1fr); }

@media (max-width: 767px) {
  .grid-2,
  .grid-3 {
    grid-template-columns: 1fr;
  }
}

@media (min-width: 768px) and (max-width: 1023px) {
  .grid-3 {
    grid-template-columns: repeat(2, 1fr);
  }
}

/* Section */
.section {
  padding: var(--spacing-2xl) 0;
}

.section-title {
  font-family: var(--font-heading);
  font-size: var(--text-3xl);
  font-weight: 700;
  text-align: center;
  margin-bottom: var(--spacing-xl);
  color: var(--text-dark);
}

.section-subtitle {
  font-size: var(--text-lg);
  text-align: center;
  color: var(--text-light);
  margin-bottom: var(--spacing-3xl);
  max-width: 600px;
  margin-left: auto;
  margin-right: auto;
}

@media (min-width: 768px) {
  .section {
    padding: var(--spacing-3xl) 0;
  }
}

/* Utilities */
.text-center { text-align: center; }
.text-left { text-align: left; }
.text-right { text-align: right; }

.mb-sm { margin-bottom: var(--spacing-sm); }
.mb-md { margin-bottom: var(--spacing-md); }
.mb-lg { margin-bottom: var(--spacing-lg); }
.mb-xl { margin-bottom: var(--spacing-xl); }

.mt-sm { margin-top: var(--spacing-sm); }
.mt-md { margin-top: var(--spacing-md); }
.mt-lg { margin-top: var(--spacing-lg); }
.mt-xl { margin-top: var(--spacing-xl); }

.hidden { display: none; }
.block { display: block; }
.flex { display: flex; }
.inline-flex { display: inline-flex; }

/* Featured Course Styles */
.featured-course {
    margin-bottom: var(--spacing-3xl);
}

.card-featured {
    background: var(--gradient-primary);
    color: var(--white);
    border-radius: var(--radius-xl);
    overflow: hidden;
    box-shadow: var(--shadow-xl);
}

.card-featured-content {
    display: grid;
    grid-template-columns: 1fr;
    gap: 0;
}

.card-featured-image {
    position: relative;
    overflow: hidden;
}

.card-featured-image::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(46, 91, 186, 0.3);
    z-index: 1;
}

.card-featured-image .card-image {
    height: 250px;
    width: 100%;
    object-fit: cover;
}

.card-featured-info {
    position: relative;
    z-index: 2;
    padding: var(--spacing-xl);
}

.card-featured .card-title {
    color: var(--white);
    font-size: var(--text-2xl);
    margin-bottom: var(--spacing-md);
}

.card-featured .card-subtitle {
    color: rgba(255, 255, 255, 0.8);
    margin-bottom: var(--spacing-lg);
}

.card-featured .card-price {
    color: var(--accent-gold);
}

.card-featured .card-duration {
    background: rgba(255, 255, 255, 0.2);
    color: var(--white);
}

.card-featured .card-text {
    color: rgba(255, 255, 255, 0.9);
    font-size: var(--text-base);
    line-height: 1.6;
}

.card-featured .btn {
    background: var(--gradient-accent);
    border: none;
}

/* Desktop Layout for Featured Course */
@media (min-width: 768px) {
    .card-featured-content {
        grid-template-columns: 400px 1fr;
        align-items: center;
    }
    
    .card-featured-image {
        height: 100%;
    }
    
    .card-featured-image .card-image {
        height: 100%;
        min-height: 300px;
    }
    
    .card-featured-info {
        padding: var(--spacing-2xl);
    }
    
    .card-featured .card-title {
        font-size: var(--text-3xl);
    }
}

@media (min-width: 1024px) {
    .card-featured-content {
        grid-template-columns: 500px 1fr;
    }
    
    .card-featured-info {
        padding: var(--spacing-3xl);
    }
}