/* QAStudy.online Design System - Basic CSS */

/* Reset and base styles */
*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Oxygen', 'Ubuntu', 'Cantarell', sans-serif;
  font-size: 16px;
  font-weight: 400;
  line-height: 1.5;
  color: #374151;
  background-color: #ffffff;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* Container */
.container {
  width: 100%;
  max-width: 1280px;
  margin: 0 auto;
  padding-left: 1rem;
  padding-right: 1rem;
}

@media (min-width: 640px) {
  .container {
    padding-left: 1.5rem;
    padding-right: 1.5rem;
  }
}

@media (min-width: 1024px) {
  .container {
    padding-left: 2rem;
    padding-right: 2rem;
  }
}

/* Typography */
h1, .h1 {
  font-size: 2.25rem;
  font-weight: 800;
  line-height: 1.25;
  color: #111827;
  margin-bottom: 1.5rem;
}

h2, .h2 {
  font-size: 1.875rem;
  font-weight: 700;
  line-height: 1.25;
  color: #111827;
  margin-bottom: 1.25rem;
}

h3, .h3 {
  font-size: 1.5rem;
  font-weight: 600;
  line-height: 1.375;
  color: #111827;
  margin-bottom: 1rem;
}

h4, .h4 {
  font-size: 1.25rem;
  font-weight: 600;
  line-height: 1.375;
  color: #111827;
  margin-bottom: 0.75rem;
}

.text-large {
  font-size: 1.125rem;
  line-height: 1.625;
}

.text-primary {
  color: #7c3aed;
}

.text-gray {
  color: #6b7280;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.75rem 1.5rem;
  font-size: 0.875rem;
  font-weight: 500;
  line-height: 1;
  text-align: center;
  text-decoration: none;
  white-space: nowrap;
  vertical-align: middle;
  cursor: pointer;
  user-select: none;
  border: 1px solid transparent;
  border-radius: 0.375rem;
  transition: all 150ms ease-in-out;
}

.btn-primary {
  color: #ffffff;
  background-color: #7c3aed;
  border-color: #7c3aed;
}

.btn-primary:hover {
  background-color: #6d28d9;
  border-color: #6d28d9;
  transform: translateY(-1px);
  box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -2px rgba(0, 0, 0, 0.1);
}

.btn-secondary {
  color: #7c3aed;
  background-color: #ffffff;
  border-color: #7c3aed;
}

.btn-secondary:hover {
  color: #6d28d9;
  background-color: #f3f0ff;
  border-color: #6d28d9;
}

.btn-lg {
  padding: 1rem 2rem;
  font-size: 1.125rem;
}

/* Cards */
.card {
  position: relative;
  display: flex;
  flex-direction: column;
  min-width: 0;
  background-color: #ffffff;
  background-clip: border-box;
  border: 1px solid #e5e7eb;
  border-radius: 0.5rem;
  box-shadow: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  transition: all 150ms ease-in-out;
}

.card:hover {
  box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -2px rgba(0, 0, 0, 0.1);
  transform: translateY(-2px);
}

.card-body {
  flex: 1 1 auto;
  padding: 1.5rem;
}

/* Grid */
.grid {
  display: grid;
}

.grid-cols-1 {
  grid-template-columns: repeat(1, minmax(0, 1fr));
}

@media (min-width: 768px) {
  .md\:grid-cols-2 {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
  
  .md\:grid-cols-3 {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
  
  .md\:grid-cols-4 {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

@media (min-width: 1024px) {
  .lg\:grid-cols-3 {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
  
  .lg\:grid-cols-4 {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

.gap-8 {
  gap: 2rem;
}

/* Spacing */
.py-20 {
  padding-top: 5rem;
  padding-bottom: 5rem;
}

.mb-4 {
  margin-bottom: 1rem;
}

.mb-16 {
  margin-bottom: 4rem;
}

.mt-12 {
  margin-top: 3rem;
}

/* Background colors */
.bg-gray-50 {
  background-color: #f9fafb;
}

.bg-primary-100 {
  background-color: #e9e2ff;
}

/* Text alignment */
.text-center {
  text-align: center;
}

/* Flexbox utilities */
.d-flex {
  display: flex;
}

.justify-between {
  justify-content: space-between;
}

.align-center {
  align-items: center;
}

/* Hero section */
.hero {
  position: relative;
  padding: 6rem 0;
  background: linear-gradient(135deg, #f3f0ff 0%, #e9e2ff 100%);
  overflow: hidden;
}

.hero-content {
  display: grid;
  grid-template-columns: 1fr;
  gap: 3rem;
  align-items: center;
}

@media (min-width: 1024px) {
  .hero-content {
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
  }
}

.hero-text {
  text-align: center;
}

@media (min-width: 1024px) {
  .hero-text {
    text-align: left;
  }
}

.hero-description {
  font-size: 1.125rem;
  color: #6b7280;
  margin-bottom: 2rem;
  line-height: 1.625;
}

.hero-actions {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

@media (min-width: 640px) {
  .hero-actions {
    flex-direction: row;
    justify-content: center;
  }
}

@media (min-width: 1024px) {
  .hero-actions {
    justify-content: flex-start;
  }
}

/* Course grid */
.course-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 2rem;
  margin-top: 2rem;
}

@media (max-width: 640px) {
  .course-grid {
    grid-template-columns: 1fr;
    gap: 1.5rem;
  }
}

.course-card {
  overflow: hidden;
  transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

.course-card:hover {
  transform: translateY(-8px);
  box-shadow: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 8px 10px -6px rgba(0, 0, 0, 0.1);
}

.course-image {
  position: relative;
  width: 100%;
  height: 200px;
  background: linear-gradient(135deg, #9b73ff 0%, #7c3aed 100%);
  display: flex;
  align-items: center;
  justify-content: center;
  color: #ffffff;
  font-size: 1.125rem;
  font-weight: 600;
  overflow: hidden;
  transition: transform 150ms ease-in-out;
}

.course-image-content {
  text-align: center;
  padding: 1rem;
}

.course-content {
  padding: 1.5rem;
}

.course-category {
  display: inline-block;
  padding: 0.25rem 0.75rem;
  background-color: #f3f0ff;
  color: #5b21b6;
  font-size: 0.75rem;
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  border-radius: 9999px;
  margin-bottom: 0.75rem;
}

.course-title {
  font-size: 1.125rem;
  font-weight: 600;
  color: #111827;
  margin-bottom: 0.75rem;
  line-height: 1.375;
}

.course-title a {
  color: inherit;
  text-decoration: none;
  transition: color 150ms ease-in-out;
}

.course-title a:hover {
  color: #7c3aed;
}

.course-description {
  color: #6b7280;
  font-size: 0.875rem;
  line-height: 1.625;
  margin-bottom: 1rem;
}

.course-instructor {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  margin-bottom: 1rem;
  font-size: 0.875rem;
  color: #6b7280;
}

.instructor-avatar {
  width: 1.5rem;
  height: 1.5rem;
  border-radius: 9999px;
  background-color: #e5e7eb;
}

.course-stats {
  display: flex;
  gap: 1rem;
  margin-bottom: 1rem;
  font-size: 0.875rem;
  color: #6b7280;
}

.stat-item {
  display: flex;
  align-items: center;
  gap: 0.25rem;
}

.icon {
  width: 1rem;
  height: 1rem;
}

.course-meta {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding-top: 1rem;
  border-top: 1px solid #e5e7eb;
}

.course-rating {
  display: flex;
  align-items: center;
  gap: 0.25rem;
  font-size: 0.875rem;
  font-weight: 500;
}

.stars {
  color: #f59e0b;
}

.rating-count {
  color: #6b7280;
}

.course-price {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.current-price {
  font-size: 1.125rem;
  font-weight: 700;
  color: #7c3aed;
}

.original-price {
  font-size: 0.875rem;
  color: #6b7280;
  text-decoration: line-through;
}

/* Navigation */
.navbar {
  position: sticky;
  top: 0;
  z-index: 1020;
  width: 100%;
  background-color: #ffffff;
  border-bottom: 1px solid #e5e7eb;
  box-shadow: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  transition: all 150ms ease-in-out;
}

.navbar-brand {
  display: inline-flex;
  align-items: center;
  font-size: 1.25rem;
  font-weight: 800;
  color: #7c3aed;
  text-decoration: none;
  transition: color 150ms ease-in-out;
}

.navbar-brand:hover {
  color: #6d28d9;
  text-decoration: none;
}

.navbar-nav {
  display: flex;
  align-items: center;
  gap: 2rem;
  list-style: none;
  margin: 0;
  padding: 0;
}

@media (max-width: 768px) {
  .navbar-nav {
    display: none;
  }
}

.nav-link {
  display: flex;
  align-items: center;
  padding: 0.5rem 0;
  font-weight: 500;
  color: #374151;
  text-decoration: none;
  transition: color 150ms ease-in-out;
}

.nav-link:hover {
  color: #7c3aed;
  text-decoration: none;
}

.navbar-actions {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.btn-ghost {
  color: #6b7280;
  background-color: transparent;
  border-color: transparent;
}

.btn-ghost:hover {
  color: #111827;
  background-color: #f3f4f6;
}

/* Footer */
.footer {
  background-color: #111827;
  color: #d1d5db;
  padding: 4rem 0 2rem;
}

.footer-content {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 2rem;
  margin-bottom: 3rem;
}

@media (max-width: 768px) {
  .footer-content {
    grid-template-columns: 1fr;
    text-align: center;
    gap: 3rem;
  }
}

.footer-section h3 {
  color: #ffffff;
  font-size: 1.125rem;
  font-weight: 600;
  margin-bottom: 1rem;
}

.footer-links {
  list-style: none;
  margin: 0;
  padding: 0;
}

.footer-links li {
  margin-bottom: 0.5rem;
}

.footer-links a {
  color: #d1d5db;
  text-decoration: none;
  transition: color 150ms ease-in-out;
}

.footer-links a:hover {
  color: #a78bfa;
  text-decoration: none;
}

.footer-brand h3 {
  color: #a78bfa;
  font-size: 1.25rem;
  font-weight: 800;
  margin-bottom: 0.75rem;
}

.footer-bottom {
  padding-top: 2rem;
  border-top: 1px solid #374151;
  text-align: center;
  color: #9ca3af;
  font-size: 0.875rem;
}

.footer-bottom-content {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

@media (min-width: 768px) {
  .footer-bottom-content {
    flex-direction: row;
    justify-content: space-between;
    align-items: center;
  }
}

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

.footer-bottom-links a {
  color: #9ca3af;
  text-decoration: none;
  transition: color 150ms ease-in-out;
}

.footer-bottom-links a:hover {
  color: #a78bfa;
}

/* Utility classes */
.space-y-2 > * + * {
  margin-top: 0.5rem;
}

.w-16 {
  width: 4rem;
}

.h-16 {
  height: 4rem;
}

.w-8 {
  width: 2rem;
}

.h-8 {
  height: 2rem;
}

.rounded-full {
  border-radius: 9999px;
}

.mx-auto {
  margin-left: auto;
  margin-right: auto;
}

.mb-3 {
  margin-bottom: 0.75rem;
}

.mb-4 {
  margin-bottom: 1rem;
}

.text-primary {
  color: #7c3aed;
}

.text-gray-600 {
  color: #6b7280;
}

.hover\:text-primary:hover {
  color: #7c3aed;
}