:root {
  --primary: #667eea;
  --secondary: #764ba2;
  --accent: #f5576c;
  --text: #333;
  --text-light: #666;
  --bg: #f5f5f5;
  --white: #fff;
  --shadow: rgba(0, 0, 0, 0.1);
}

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

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  font-size: 16px;
}

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

header {
  background: linear-gradient(135deg, var(--primary) 0%, var(--secondary) 100%);
  color: var(--white);
  padding: 1.5rem 0;
  box-shadow: 0 2px 10px var(--shadow);
  position: sticky;
  top: 0;
  z-index: 1000;
}

.logo {
  font-size: 1.8rem;
  font-weight: bold;
  margin-bottom: 1rem;
  letter-spacing: 1px;
}

nav ul {
  list-style: none;
  display: flex;
  flex-wrap: nowrap;
  justify-content: space-between;
  align-items: center;
  gap: 0;
}

nav ul li {
  flex: 1 1 0;
  min-width: 0;
  text-align: center;
}

nav ul li a {
  color: var(--white);
  text-decoration: none;
  padding: 0.5rem;
  display: block;
  transition: all 0.3s ease;
  border-radius: 4px;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  font-weight: 500;
}

nav ul li a:hover {
  background: rgba(255, 255, 255, 0.15);
  transform: translateY(-2px);
}

main {
  min-height: calc(100vh - 400px);
}

h1, h2, h3, h4 {
  font-weight: 600;
  line-height: 1.3;
}

a {
  transition: all 0.3s ease;
}

a:hover {
  opacity: 0.8;
}

.video-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 1.5rem;
}

.video-card {
  background: var(--white);
  padding: 1.5rem;
  border-radius: 8px;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.05);
  transition: all 0.3s ease;
}

.video-card:hover {
  transform: translateY(-5px);
  box-shadow: 0 4px 15px rgba(102, 126, 234, 0.2);
}

footer {
  background: var(--text);
  color: var(--white);
  padding: 2rem 0;
  margin-top: 3rem;
  text-align: center;
}

footer nav a {
  color: var(--white);
  margin: 0 1rem;
  text-decoration: none;
  font-size: 0.95rem;
}

footer nav a:hover {
  color: var(--primary);
}

@media (max-width: 768px) {
  .logo {
    font-size: 1.4rem;
    margin-bottom: 0.8rem;
  }

  nav ul {
    font-size: 0.9rem;
  }

  nav ul li a {
    padding: 0.4rem 0.2rem;
    font-size: 0.85rem;
  }

  .video-grid {
    grid-template-columns: 1fr;
    gap: 1rem;
  }

  .container {
    padding: 0 15px;
  }

  h1 {
    font-size: 1.5rem;
  }

  h2 {
    font-size: 1.3rem;
  }

  footer nav a {
    display: block;
    margin: 0.5rem 0;
  }
}

@media (max-width: 480px) {
  nav ul {
    font-size: 0.8rem;
  }

  nav ul li a {
    padding: 0.3rem 0.1rem;
    font-size: 0.75rem;
  }

  .logo {
    font-size: 1.2rem;
  }
}

.ui-style-7 {
  --primary: #667eea;
  --secondary: #764ba2;
  --accent: #f5576c;
}

.back-to-top {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  background: var(--primary);
  color: var(--white);
  width: 50px;
  height: 50px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  box-shadow: 0 4px 10px var(--shadow);
  opacity: 0;
  transition: all 0.3s ease;
  z-index: 999;
}

.back-to-top.show {
  opacity: 1;
}

.back-to-top:hover {
  transform: translateY(-5px);
  box-shadow: 0 6px 15px var(--shadow);
}