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

:root {
  --primary-color: #6366f1;
  --primary-dark: #4f46e5;
  --secondary-color: #8b5cf6;
  --accent-color: #06b6d4;
  --text-primary: #1f2937;
  --text-secondary: #6b7280;
  --text-light: #9ca3af;
  --bg-primary: #ffffff;
  --bg-secondary: #f8fafc;
  --bg-dark: #0f172a;
  --border-color: #e5e7eb;
  --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
  --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
  --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
  --shadow-xl: 0 20px 25px -5px rgb(0 0 0 / 0.1), 0 8px 10px -6px rgb(0 0 0 / 0.1);
}

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  line-height: 1.6;
  color: var(--text-primary);
  background-color: var(--bg-primary);
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
}

/* Navigation */
.navbar {
  position: fixed;
  top: 0;
  width: 100%;
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border-color);
  z-index: 1000;
  transition: all 0.3s ease;
}

.nav-container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  height: 70px;
}

.nav-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 24px;
  font-weight: 700;
  color: var(--primary-color);
}

.nav-logo i {
  font-size: 28px;
}

.nav-menu {
  display: flex;
  list-style: none;
  gap: 30px;
}

.nav-link {
  text-decoration: none;
  color: var(--text-primary);
  font-weight: 500;
  transition: color 0.3s ease;
  position: relative;
}

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

.nav-link::after {
  content: '';
  position: absolute;
  bottom: -5px;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--primary-color);
  transition: width 0.3s ease;
}

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

.hamburger {
  display: none;
  flex-direction: column;
  cursor: pointer;
}

.bar {
  width: 25px;
  height: 3px;
  background: var(--text-primary);
  margin: 3px 0;
  transition: 0.3s;
}

/* Hero Section */
.hero {
  padding: 120px 0 80px;
  background: linear-gradient(135deg, #f8fafc 0%, #e2e8f0 100%);
  overflow: hidden;
  position: relative;
}

.hero::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100"><defs><pattern id="grid" width="10" height="10" patternUnits="userSpaceOnUse"><path d="M 10 0 L 0 0 0 10" fill="none" stroke="%23e2e8f0" stroke-width="0.5"/></pattern></defs><rect width="100" height="100" fill="url(%23grid)"/></svg>');
  opacity: 0.3;
}

.hero-container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 60px;
  align-items: center;
  position: relative;
  z-index: 1;
}

.hero-content {
  animation: slideInLeft 0.8s ease-out;
}

.hero-title {
  font-size: 3.5rem;
  font-weight: 700;
  line-height: 1.1;
  margin-bottom: 24px;
  color: var(--text-primary);
}

.gradient-text {
  background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-subtitle {
  font-size: 1.25rem;
  color: var(--text-secondary);
  margin-bottom: 40px;
  line-height: 1.6;
}

.search-container {
  margin-bottom: 40px;
}

.search-box {
  display: flex;
  align-items: center;
  background: white;
  border-radius: 50px;
  padding: 4px;
  box-shadow: var(--shadow-lg);
  border: 2px solid transparent;
  transition: all 0.3s ease;
}

.search-box:focus-within {
  border-color: var(--primary-color);
  box-shadow: var(--shadow-xl);
}

.search-box i {
  color: var(--text-light);
  margin-left: 20px;
  font-size: 18px;
}

.search-input {
  flex: 1;
  border: none;
  outline: none;
  padding: 16px 20px;
  font-size: 16px;
  background: transparent;
}

.search-input::placeholder {
  color: var(--text-light);
}

.search-btn {
  background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
  color: white;
  border: none;
  padding: 12px 24px;
  border-radius: 50px;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.3s ease;
}

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

.hero-cta {
  display: flex;
  gap: 20px;
  align-items: center;
}

.cta-primary {
  background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
  color: white;
  border: none;
  padding: 16px 32px;
  border-radius: 50px;
  font-size: 16px;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.3s ease;
  box-shadow: var(--shadow-md);
}

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

.cta-primary.large {
  padding: 20px 40px;
  font-size: 18px;
}

.cta-secondary {
  background: transparent;
  color: var(--text-primary);
  border: 2px solid var(--border-color);
  padding: 14px 28px;
  border-radius: 50px;
  font-size: 16px;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.3s ease;
  display: flex;
  align-items: center;
  gap: 8px;
}

.cta-secondary:hover {
  border-color: var(--primary-color);
  color: var(--primary-color);
  transform: translateY(-2px);
}

/* Hero Visual */
.hero-visual {
  position: relative;
  animation: slideInRight 0.8s ease-out;
}

.floating-cards {
  position: relative;
  height: 400px;
}

.card {
  position: absolute;
  background: white;
  border-radius: 20px;
  padding: 24px;
  box-shadow: var(--shadow-lg);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 12px;
  transition: all 0.3s ease;
  cursor: pointer;
}

.card:hover {
  transform: translateY(-10px);
  box-shadow: var(--shadow-xl);
}

.card i {
  font-size: 32px;
  color: var(--primary-color);
}

.card span {
  font-weight: 600;
  color: var(--text-primary);
}

.card-1 {
  top: 20px;
  left: 50px;
  animation: float 3s ease-in-out infinite;
}

.card-2 {
  top: 120px;
  right: 30px;
  animation: float 3s ease-in-out infinite 0.5s;
}

.card-3 {
  bottom: 120px;
  left: 20px;
  animation: float 3s ease-in-out infinite 1s;
}

.card-4 {
  bottom: 30px;
  right: 60px;
  animation: float 3s ease-in-out infinite 1.5s;
}

/* Section Styles */
section {
  padding: 80px 0;
}

.section-title {
  text-align: center;
  font-size: 2.5rem;
  font-weight: 700;
  margin-bottom: 60px;
  color: var(--text-primary);
}

/* Suggested Topics */
.suggested-topics {
  background: var(--bg-secondary);
}

.topics-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 30px;
}

.topic-card {
  background: white;
  border-radius: 20px;
  padding: 32px;
  text-align: center;
  box-shadow: var(--shadow-md);
  transition: all 0.3s ease;
  border: 1px solid var(--border-color);
}

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

.topic-icon {
  width: 80px;
  height: 80px;
  background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
  border-radius: 20px;
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto 20px;
}

.topic-icon i {
  font-size: 32px;
  color: white;
}

.topic-card h3 {
  font-size: 1.5rem;
  font-weight: 600;
  margin-bottom: 12px;
  color: var(--text-primary);
}

.topic-card p {
  color: var(--text-secondary);
  margin-bottom: 20px;
}

.topic-difficulty {
  background: var(--bg-secondary);
  color: var(--text-secondary);
  padding: 6px 16px;
  border-radius: 20px;
  font-size: 14px;
  font-weight: 500;
}

/* Features Section */
.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 40px;
}

.feature-card {
  text-align: center;
  padding: 40px 20px;
}

.feature-icon {
  width: 100px;
  height: 100px;
  background: linear-gradient(135deg, var(--accent-color), var(--primary-color));
  border-radius: 25px;
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto 24px;
  box-shadow: var(--shadow-md);
}

.feature-icon i {
  font-size: 40px;
  color: white;
}

.feature-card h3 {
  font-size: 1.5rem;
  font-weight: 600;
  margin-bottom: 16px;
  color: var(--text-primary);
}

.feature-card p {
  color: var(--text-secondary);
  line-height: 1.6;
}

/* Testimonials */
.testimonials {
  background: var(--bg-secondary);
}

.testimonials-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
  gap: 30px;
}

.testimonial-card {
  background: white;
  border-radius: 20px;
  padding: 32px;
  box-shadow: var(--shadow-md);
  transition: all 0.3s ease;
}

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

.stars {
  display: flex;
  gap: 4px;
  margin-bottom: 16px;
}

.stars i {
  color: #fbbf24;
  font-size: 16px;
}

.testimonial-content p {
  font-size: 1.1rem;
  line-height: 1.6;
  color: var(--text-primary);
  margin-bottom: 24px;
  font-style: italic;
}

.testimonial-author {
  display: flex;
  align-items: center;
  gap: 16px;
}

.testimonial-author img {
  width: 50px;
  height: 50px;
  border-radius: 50%;
  object-fit: cover;
}

.author-info h4 {
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 4px;
}

.author-info span {
  color: var(--text-secondary);
  font-size: 14px;
}

/* Final CTA */
.final-cta {
  background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
  color: white;
  text-align: center;
}

.cta-content h2 {
  font-size: 2.5rem;
  font-weight: 700;
  margin-bottom: 16px;
}

.cta-content p {
  font-size: 1.25rem;
  margin-bottom: 32px;
  opacity: 0.9;
}

.cta-content .cta-primary {
  background: white;
  color: var(--primary-color);
  border: none;
}

.cta-content .cta-primary:hover {
  background: var(--bg-secondary);
  transform: translateY(-2px);
}

/* Footer */
.footer {
  background: var(--bg-dark);
  color: white;
  padding: 60px 0 20px;
}

.footer-content {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 40px;
  margin-bottom: 40px;
}

.footer-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 24px;
  font-weight: 700;
  color: var(--primary-color);
  margin-bottom: 16px;
}

.footer-section h4 {
  font-size: 1.1rem;
  font-weight: 600;
  margin-bottom: 16px;
  color: white;
}

.footer-section ul {
  list-style: none;
}

.footer-section ul li {
  margin-bottom: 8px;
}

.footer-section ul li a {
  color: #94a3b8;
  text-decoration: none;
  transition: color 0.3s ease;
}

.footer-section ul li a:hover {
  color: var(--primary-color);
}

.footer-section p {
  color: #94a3b8;
  line-height: 1.6;
}

.footer-bottom {
  border-top: 1px solid #334155;
  padding-top: 20px;
  text-align: center;
  color: #94a3b8;
}

/* Animations */
@keyframes slideInLeft {
  from {
    opacity: 0;
    transform: translateX(-50px);
  }

  to {
    opacity: 1;
    transform: translateX(0);
  }
}

@keyframes slideInRight {
  from {
    opacity: 0;
    transform: translateX(50px);
  }

  to {
    opacity: 1;
    transform: translateX(0);
  }
}

@keyframes float {

  0%,
  100% {
    transform: translateY(0px);
  }

  50% {
    transform: translateY(-20px);
  }
}

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

  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* Responsive Design */
@media (max-width: 768px) {
  .hamburger {
    display: flex;
  }

  .nav-menu {
    position: fixed;
    left: -100%;
    top: 70px;
    flex-direction: column;
    background-color: white;
    width: 100%;
    text-align: center;
    transition: 0.3s;
    box-shadow: var(--shadow-lg);
    padding: 20px 0;
  }

  .nav-menu.active {
    left: 0;
  }

  .nav-menu li {
    margin: 15px 0;
  }

  .hero-container {
    grid-template-columns: 1fr;
    text-align: center;
    gap: 40px;
  }

  .hero-title {
    font-size: 2.5rem;
  }

  .hero-cta {
    justify-content: center;
    flex-wrap: wrap;
  }

  .floating-cards {
    height: 300px;
  }

  .card {
    padding: 16px;
  }

  .card i {
    font-size: 24px;
  }

  .section-title {
    font-size: 2rem;
  }

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

  .footer-content {
    grid-template-columns: 1fr;
    text-align: center;
  }

  .search-box {
    flex-direction: column;
    border-radius: 20px;
    padding: 8px;
  }

  .search-input {
    margin: 8px 0;
  }

  .search-btn {
    border-radius: 20px;
  }
}

@media (max-width: 480px) {
  .hero-title {
    font-size: 2rem;
  }

  .hero-subtitle {
    font-size: 1.1rem;
  }

  .cta-content h2 {
    font-size: 2rem;
  }

  .section-title {
    font-size: 1.8rem;
  }

  .topic-card,
  .testimonial-card {
    padding: 24px;
  }

  .feature-card {
    padding: 30px 15px;
  }
}