:root {
  --primary-dark: #0A2C4B;
  --primary-light: #3F87FF;
  --accent: #FF9D00;
  --bg-light: #F5F5F5;
  --text-dark: #333333;
  --text-light: #FFFFFF;
  --shadow: 0 4px 20px rgba(0, 0, 0, 0.1);
}

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

body {
  background: linear-gradient(135deg, #F5F5F5 0%, #E0E0E0 100%);
  font-family: 'Helvetica', sans-serif;
  color: var(--text-dark);
  line-height: 1.6;
  overflow-x: hidden;
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 40px 20px;
}

.header {
  text-align: center;
  margin-bottom: 60px;
  position: relative;
}

.header::after {
  content: "";
  display: block;
  width: 100px;
  height: 4px;
  background: linear-gradient(90deg, var(--primary-light), var(--accent));
  margin: 20px auto;
  border-radius: 2px;
}

h1, h2, h3 {
  font-family: 'Roboto', sans-serif;
  font-weight: bold;
  color: var(--primary-dark);
  margin-bottom: 20px;
}

h2 {
  font-size: 28px;
  position: relative;
  padding-left: 20px;
}

h2::before {
  content: "";
  position: absolute;
  left: 0;
  top: 50%;
  transform: translateY(-50%);
  width: 8px;
  height: 30px;
  background: linear-gradient(to bottom, var(--primary-light), var(--accent));
  border-radius: 4px;
}

h3 {
  font-size: 22px;
  margin-top: 40px;
  border-bottom: 2px solid var(--primary-light);
  padding-bottom: 10px;
}

p {
  margin-bottom: 20px;
  font-size: 16px;
}

.article-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 50px;
}

.article-section {
  background: white;
  border-radius: 12px;
  padding: 40px;
  box-shadow: var(--shadow);
  position: relative;
  overflow: hidden;
}

.article-section::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 5px;
  background: linear-gradient(90deg, var(--primary-dark), var(--accent));
}

.image-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 30px;
  margin: 40px 0;
}

.image-card {
  border-radius: 12px;
  overflow: hidden;
  box-shadow: var(--shadow);
  transition: transform 0.3s ease;
}

.image-card:hover {
  transform: translateY(-10px);
}

.image-card img {
  width: 100%;
  height: auto;
  display: block;
  transition: transform 0.5s ease;
}

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

.code-block {
  background: #282c34;
  color: #abb2bf;
  padding: 20px;
  border-radius: 8px;
  margin: 30px 0;
  overflow-x: auto;
  font-family: 'Courier New', monospace;
  font-size: 14px;
  line-height: 1.5;
  position: relative;
}

.code-block::before {
  content: "CSS";
  position: absolute;
  top: 0;
  left: 0;
  background: var(--accent);
  color: white;
  padding: 2px 10px;
  border-radius: 0 0 4px 0;
  font-size: 12px;
}

.notice {
  background: rgba(10, 44, 75, 0.1);
  border-left: 4px solid var(--accent);
  padding: 20px;
  margin: 40px 0;
  border-radius: 0 8px 8px 0;
}

.notice p {
  margin: 0;
  font-style: italic;
  color: var(--primary-dark);
}

.grid-animation {
  position: relative;
  height: 200px;
  margin: 40px 0;
  background: rgba(10, 44, 75, 0.05);
  border-radius: 8px;
  overflow: hidden;
}

.grid-animation::before {
  content: "";
  position: absolute;
  width: 100%;
  height: 100%;
  background-image: 
    linear-gradient(to right, rgba(10, 44, 75, 0.1) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(10, 44, 75, 0.1) 1px, transparent 1px);
  background-size: 50px 50px;
  animation: gridMove 60s linear infinite;
}

@keyframes gridMove {
  from { transform: translate(0, 0); }
  to { transform: translate(-50px, -50px); }
}

.button-demo {
  display: inline-block;
  background: var(--accent);
  color: white;
  padding: 12px 24px;
  border-radius: 30px;
  text-decoration: none;
  font-weight: bold;
  margin: 20px 0;
  position: relative;
  overflow: hidden;
  transition: all 0.3s ease;
  box-shadow: 0 4px 15px rgba(255, 157, 0, 0.3);
}

.button-demo:hover {
  transform: translateY(-3px);
  box-shadow: 0 6px 20px rgba(255, 157, 0, 0.4);
}

.button-demo::after {
  content: "";
  position: absolute;
  width: 100px;
  height: 100px;
  background: rgba(255, 255, 255, 0.3);
  border-radius: 50%;
  transform: scale(0);
  opacity: 0;
  transition: transform 0.5s, opacity 1s;
}

.button-demo:active::after {
  transform: scale(1);
  opacity: 1;
  transition: 0s;
}

@media (max-width: 768px) {
  .container {
    padding: 20px 15px;
  }
  
  .article-section {
    padding: 30px 20px;
  }
  
  h2 {
    font-size: 24px;
  }
  
  h3 {
    font-size: 20px;
  }
}

@media (max-width: 480px) {
  .image-grid {
    grid-template-columns: 1fr;
  }
}