html, body {
  background: #4682b4 !important;
  margin: 0;
  padding: 0;
  font-family: 'Montserrat', 'Segoe UI', Arial, sans-serif;
  color: #222;
}

header.main-header {
  width: 2450px;
  margin: 0 auto 0 auto;
  background: #4682b4;
  border-radius: 0;
  box-shadow: 0 4px 24px rgba(0,0,0,0.18);
  padding: 36px 24px 24px 24px;
  text-align: center;
  position: relative;
}
header.main-header h1,
header.main-header h2,
header.main-header h3,
header.main-header a {
  color: #fff !important;
}
header.main-header .main-nav {
  margin-top: 24px;
  display: flex;
  justify-content: center;
  gap: 32px;
}
header.main-header .main-nav a {
  color: #fff !important;
  text-decoration: none;
  font-weight: 600;
  font-size: 1.1rem;
  padding: 8px 20px;
  border-radius: 18px;
  transition: background 0.2s, color 0.2s;
}
header.main-header .main-nav a:hover {
  background: #fff;
  color: #4682b4 !important;
}
@media (max-width: 900px) {
  header.main-header {
    width: 95%;
    padding: 18px 4px 12px 4px;
  }
  header.main-header .main-nav {
    gap: 12px;
  }
}

.subtitle {
  font-size: 1.2rem;
  margin-bottom: 20px;
  color: #e6f2ff;
}
.main-nav {
  margin: 0 auto 0 auto;
  display: flex;
  justify-content: center;
  gap: 30px;
}
.main-nav a {
  color: #fff;
  text-decoration: none;
  font-weight: 600;
  font-size: 1rem;
  padding: 8px 18px;
  border-radius: 20px;
  transition: background 0.2s, color 0.2s;
}
.main-nav a:hover {
  background: #fff;
  color: #4682b4;
}

.hero-section {
  background: linear-gradient(120deg, #6a82fb 0%, #87ceeb 100%);
  color: #fff;
  text-align: center;
  padding: 70px 20px 40px 20px;
  position: relative;
  overflow: hidden;
}
.hero-content {
  max-width: 700px;
  margin: 0 auto;
}
.hero-section h1 {
  margin: 0 0 10px 0;
  font-size: 3rem;
  letter-spacing: 2px;
  font-weight: 700;
}
.subtitle {
  font-size: 1.3rem;
  margin-bottom: 30px;
  color: #f8f8f8;
}
.cta-btn {
  display: inline-block;
  background: #fff;
  color: #4682b4;
  font-weight: 700;
  font-size: 1.1rem;
  padding: 14px 38px;
  border-radius: 30px;
  text-decoration: none;
  box-shadow: 0 4px 24px rgba(252,92,125,0.12);
  transition: background 0.2s, color 0.2s, box-shadow 0.2s;
  margin-top: 10px;
}
.cta-btn:hover {
  background: #4682b4;
  color: #fff;
  box-shadow: 0 8px 32px rgba(252,92,125,0.18);
}

.sticky-nav {
  position: sticky;
  top: 0;
  background: rgba(70, 130, 180, 0.95);
  z-index: 100;
  display: flex;
  justify-content: center;
  gap: 30px;
  padding: 12px 0;
  border-radius: 0 0 18px 18px;
  box-shadow: 0 2px 12px rgba(0,0,0,0.08);
  margin-top: 30px;
}
.main-nav a {
  color: #fff;
  text-decoration: none;
  font-weight: 600;
  font-size: 1rem;
  padding: 8px 18px;
  border-radius: 20px;
  transition: background 0.2s, color 0.2s;
}
.main-nav a:hover {
  background: #fff;
  color: #4682b4;
}

.main-nav.sticky-nav {
  background: #000 !important;
}

main {
  max-width: 1300px;
  margin: 0 auto;
}

.course-section {
  padding: 60px 0 40px 0;
}
.course-black {
  background: #b0c4de;
}
.course-white {
  background: #b0c4de;
}

.course-cards-row {
  display: flex;
  gap: 40px;
  justify-content: center;
  align-items: stretch;
  flex-wrap: wrap;
}
.course-cards-row .course-card {
  flex: 1 1 380px;
  max-width: 520px;
  min-width: 320px;
  margin: 0;
}
@media (max-width: 1100px) {
  .course-cards-row {
    flex-direction: column;
    gap: 24px;
    align-items: center;
  }
  .course-cards-row .course-card {
    max-width: 95vw;
  }
}

.course-card {
  background: #b0c4de;
  color: #fff;
  border-radius: 28px;
  box-shadow: 0 8px 32px rgba(34,34,34,0.10);
  padding: 48px 36px;
  margin: 0 auto 40px auto;
  max-width: 700px;
  position: relative;
  backdrop-filter: blur(2px);
  transition: box-shadow 0.2s;
}
.course-black .course-card {
  background: rgba(176, 196, 222, 0.98);
  color: #fff;
}
.course-card h2 {
  margin-top: 0;
  font-size: 2.2rem;
  text-align: center;
  font-weight: 700;
}
.author-photo {
  display: block;
  margin: 24px auto 14px auto;
  width: 120px;
  height: 120px;
  object-fit: cover;
  border-radius: 50%;
  border: 4px solid #eee;
  box-shadow: 0 2px 8px rgba(0,0,0,0.10);
}
.course-info {
  text-align: center;
  margin-bottom: 22px;
}
.course-desc {
  background: #e6f2ff;
  border-radius: 16px;
  padding: 18px 20px;
  margin-bottom: 22px;
  color: #222;
  font-size: 1.08rem;
}
.course-black .course-desc {
  background: #a4c8f0;
  color: #fff;
}
.course-features ul {
  padding-left: 20px;
  margin: 0 0 22px 0;
}
.course-features li {
  margin-bottom: 10px;
  font-size: 1.05rem;
  display: flex;
  align-items: center;
  gap: 10px;
}
.accent {
  color: #4682b4;
}
.course-price {
  font-size: 1.2rem;
  font-weight: 700;
  margin: 22px 0;
  text-align: center;
  color: #2a7b2a;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
}
.course-black .course-price {
  color: #2a7b2a;
}
.course-faq {
  margin: 22px 0;
}
.faq-item {
  background: #e6f2ff;
  border-radius: 12px;
  padding: 14px 18px;
  margin-bottom: 12px;
  color: #222;
  font-size: 1.05rem;
  display: flex;
  align-items: flex-start;
  gap: 10px;
}
.course-black .faq-item {
  background: #a4c8f0;
  color: #fff;
  border: 1px solid #4682b4;
}
.course-program {
  background: #e6f2ff;
  border-radius: 16px;
  padding: 18px 20px;
  margin-top: 22px;
}
.course-black .course-program {
  background: #a4c8f0;
  color: #fff;
}
.course-program h4 {
  margin-top: 0;
  display: flex;
  align-items: center;
  gap: 8px;
}

.wavy-divider {
  width: 100%;
  overflow: hidden;
  line-height: 0;
  background: none;
  margin: 0 !important;
  padding: 0 !important;
}
.wavy-divider svg {
  display: block;
  width: 100%;
  height: 60px;
}

.fade-in {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.8s cubic-bezier(.4,0,.2,1), transform 0.8s cubic-bezier(.4,0,.2,1);
}
.fade-in.visible {
  opacity: 1;
  transform: none;
}

.main-footer {
  background: #4682b4;
  color: #fff;
  text-align: center;
  padding: 36px 10px 24px 10px;
  border-radius: 24px 24px 0 0;
  margin-top: 40px;
}
.footer-content {
  max-width: 900px;
  margin: 0 auto;
}
.footer-social a {
  color: #fff;
  text-decoration: none;
  margin: 0 8px;
  font-weight: 600;
  transition: color 0.2s;
  display: inline-flex;
  align-items: center;
  gap: 6px;
}
.footer-social a:hover {
  color: #e6f2ff;
}
.footer-links {
  margin-top: 10px;
  font-size: 0.98rem;
}
.footer-links a {
  color: #fff;
  text-decoration: underline;
  margin: 0 4px;
  transition: color 0.2s;
  display: inline-flex;
  align-items: center;
  gap: 6px;
}
.footer-links a:hover {
  color: #e6f2ff;
}
.footer-copy {
  margin-top: 10px;
  font-size: 1.05rem;
}

@media (max-width: 700px) {
  .main-header {
    padding: 24px 5px 10px 5px;
  }
  .hero-section h1 {
    font-size: 1.5rem;
  }
  .main-nav {
    gap: 10px;
    flex-direction: column;
  }
  main {
    padding: 0 2px;
  }
  .course-card {
    padding: 18px 6px;
  }
  .footer-content {
    padding: 0 2px;
  }
  .wavy-divider svg {
    height: 30px;
  }
} 

section#russian-course.course-section.course-black.fade-in.visible {
  width: 100vw;
  min-height: 100vh;
  margin: 0;
  padding: 60px 0 40px 0;
  background: #4682b4;
  color: #fff;
  box-sizing: border-box;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
} 

section#social-course.course-section.course-black.fade-in.visible {
  width: 100vw;
  min-height: 100vh;
  margin: 0;
  padding: 60px 0 40px 0;
  background: #4682b4;
  color: #fff;
  box-sizing: border-box;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
} 

section#social-course.course-section.course-black.fade-in.visible {
  width: 100vw;
  min-height: 100vh;
  margin: 0;
  padding: 60px 0 40px 0;
  background: #4682b4;
  color: #fff;
  box-sizing: border-box;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
}

section#informatics-course.course-section.course-black.fade-in.visible {
  width: 100vw;
  min-height: 100vh;
  margin: 0;
  padding: 60px 0 40px 0;
  background: #4682b4;
  color: #fff;
  box-sizing: border-box;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
} 


section#history-course.course-section.course-black.fade-in.visible {
  width: 100vw;
  min-height: 100vh;
  margin: 0;
  padding: 60px 0 40px 0;
  background: #4682b4;
  color: #fff;
  box-sizing: border-box;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
} 

section#math-course {
  padding-top: 0 !important;
}