:root {
  --primary-color: #03A9F4;
  --secondary-color: #E0E0E0;
  --accent-color: #FFC107;
  --dark-color: #1A237E;
  --light-color: #FFFFFF;
  --font-main: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  --font-code: 'Consolas', 'Monaco', 'Andale Mono', monospace;
  --transition: all 0.3s cubic-bezier(0.25, 0.8, 0.25, 1);
}

body {
  margin: 0;
  padding: 0;
  font-family: var(--font-main);
  background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
  color: #333;
  line-height: 1.6;
}

.notice {
  position: fixed;
  top: 70px;
  right: 20px;
  background: rgba(255,255,255,0.9);
  padding: 10px 15px;
  border-radius: 4px;
  box-shadow: 0 2px 10px rgba(0,0,0,0.1);
  z-index: 1000;
  font-size: 14px;
}

.navbar {
  position: fixed;
  top: 0;
  width: 100%;
  background: linear-gradient(90deg, var(--dark-color), var(--primary-color));
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 15px 5%;
  box-shadow: 0 2px 10px rgba(0,0,0,0.2);
  z-index: 1000;
}

.nav-logo {
  color: var(--light-color);
  font-weight: bold;
  font-size: 1.5em;
  text-decoration: none;
}

.nav-menu {
  display: flex;
  gap: 25px;
}

.nav-link {
  color: var(--light-color);
  text-decoration: none;
  font-weight: 500;
  position: relative;
  padding: 5px 0;
}

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

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

.hamburger {
  display: none;
  cursor: pointer;
}

.main-container {
  max-width: 1200px;
  margin: 100px auto 50px;
  padding: 0 20px;
}

.hero {
  text-align: center;
  margin-bottom: 60px;
  padding: 40px 0;
  background: rgba(255,255,255,0.1);
  backdrop-filter: blur(10px);
  border-radius: 16px;
  box-shadow: 0 8px 32px rgba(0,0,0,0.1);
  border: 1px solid rgba(255,255,255,0.2);
}

.hero h1 {
  font-size: 2.8em;
  margin-bottom: 20px;
  color: var(--light-color);
  text-shadow: 0 2px 4px rgba(0,0,0,0.2);
}

.hero p {
  font-size: 1.2em;
  max-width: 800px;
  margin: 0 auto;
  color: var(--light-color);
}

.content-section {
  background: var(--light-color);
  border-radius: 12px;
  padding: 40px;
  margin-bottom: 40px;
  box-shadow: 0 10px 20px rgba(0,0,0,0.1);
  position: relative;
  overflow: hidden;
}

.content-section:before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 5px;
  height: 100%;
  background: linear-gradient(to bottom, var(--primary-color), var(--accent-color));
}

.content-section h2 {
  color: var(--primary-color);
  font-size: 1.8em;
  margin-bottom: 25px;
  position: relative;
}

.content-section h2:after {
  content: '';
  position: absolute;
  bottom: -10px;
  left: 0;
  width: 50px;
  height: 3px;
  background: var(--accent-color);
}

.content-section h3 {
  color: var(--accent-color);
  font-size: 1.4em;
  margin: 25px 0 15px;
}

.content-section p {
  margin-bottom: 20px;
  font-size: 1.05em;
}

.image-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 20px;
  margin: 30px 0;
}

.image-card {
  border-radius: 8px;
  overflow: hidden;
  box-shadow: 0 4px 8px rgba(0,0,0,0.1);
  transition: var(--transition);
  position: relative;
}

.image-card:hover {
  transform: translateY(-5px);
  box-shadow: 0 10px 20px rgba(0,0,0,0.2);
}

.image-card img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: var(--transition);
}

.image-card:hover img {
  transform: scale(1.05);
}

pre {
  background: #2d2d2d;
  color: #f8f8f2;
  padding: 20px;
  border-radius: 8px;
  overflow-x: auto;
  margin: 25px 0;
  font-family: var(--font-code);
  font-size: 0.95em;
  line-height: 1.5;
  position: relative;
}

pre:before {
  content: 'CSS';
  position: absolute;
  top: 0;
  right: 0;
  background: var(--primary-color);
  color: white;
  padding: 2px 10px;
  font-size: 0.8em;
  border-radius: 0 0 0 8px;
}

code {
  font-family: var(--font-code);
  background: rgba(0,0,0,0.05);
  padding: 2px 4px;
  border-radius: 3px;
  font-size: 0.9em;
}

.toc {
  position: sticky;
  top: 100px;
  background: rgba(255,255,255,0.9);
  padding: 20px;
  border-radius: 8px;
  box-shadow: 0 4px 12px rgba(0,0,0,0.1);
  margin-bottom: 30px;
}

.toc h3 {
  color: var(--primary-color);
  margin-top: 0;
}

.toc ul {
  padding-left: 20px;
}

.toc li {
  margin-bottom: 8px;
}

.toc a {
  color: #333;
  text-decoration: none;
  transition: var(--transition);
}

.toc a:hover {
  color: var(--primary-color);
}

@media (max-width: 992px) {
  .main-container {
    grid-template-columns: 1fr;
  }
  
  .toc {
    position: static;
    margin-bottom: 40px;
  }
}

@media (max-width: 768px) {
  .nav-menu {
    display: none;
  }
  
  .hamburger {
    display: block;
  }
  
  .hero h1 {
    font-size: 2em;
  }
  
  .content-section {
    padding: 30px 20px;
  }
  
  .image-grid {
    grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
  }
}

@keyframes fadeIn {
  from {
    opacity: 0;
    transform: translateY(20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.content-section {
  animation: fadeIn 0.6s ease forwards;
}

@keyframes float {
  0% {
    transform: translateY(0);
  }
  50% {
    transform: translateY(-10px);
  }
  100% {
    transform: translateY(0);
  }
}

.floating {
  animation: float 3s ease-in-out infinite;
}