:root {
  --primary: #B497BD;
  --secondary: #87CEEB;
  --accent: #FF69B4;
  --light: #F0F0F0;
  --dark: #2A2A3C;
  --gray: #C0C0C0;
}

@import url('https://fonts.googleapis.com/css2?family=Montserrat:wght@500;700&family=Roboto:wght@300;400;500&display=swap');

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

body {
  background: linear-gradient(135deg, #f5f7fa 0%, #e4e8f0 100%);
  font-family: 'Roboto', sans-serif;
  color: var(--dark);
  line-height: 1.6;
  padding: 0;
  margin: 0;
  overflow-x: hidden;
}

.header {
  background: linear-gradient(45deg, var(--primary), var(--secondary));
  padding: 2rem 5%;
  text-align: center;
  position: relative;
  overflow: hidden;
  box-shadow: 0 10px 30px rgba(0,0,0,0.1);
}

.header::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: url('https://images.gptkong.com/demo/sample3.png') no-repeat center center/cover;
  opacity: 0.1;
}

.header h1 {
  font-family: 'Montserrat', sans-serif;
  color: white;
  font-size: 2.5rem;
  margin-bottom: 1rem;
  text-shadow: 0 2px 10px rgba(0,0,0,0.2);
  position: relative;
}

.header p {
  color: white;
  max-width: 800px;
  margin: 0 auto;
  position: relative;
}

.notice {
  background: rgba(255,255,255,0.9);
  color: var(--dark);
  padding: 1rem;
  text-align: center;
  font-size: 0.9rem;
  border-bottom: 1px solid var(--gray);
  position: sticky;
  top: 0;
  z-index: 100;
}

.container {
  max-width: 1200px;
  margin: 3rem auto;
  padding: 0 2rem;
}

.nav-tabs {
  display: flex;
  justify-content: center;
  margin-bottom: 3rem;
  flex-wrap: wrap;
  gap: 1rem;
}

.nav-tabs a {
  text-decoration: none;
  color: var(--dark);
  padding: 0.8rem 1.5rem;
  border-radius: 50px;
  background: white;
  box-shadow: 0 5px 15px rgba(0,0,0,0.05);
  transition: all 0.3s ease;
  font-family: 'Montserrat', sans-serif;
  font-weight: 500;
  border: 2px solid transparent;
}

.nav-tabs a:hover {
  transform: translateY(-3px);
  box-shadow: 0 8px 25px rgba(0,0,0,0.1);
  border-color: var(--primary);
}

.content-section {
  background: white;
  border-radius: 15px;
  padding: 3rem;
  margin-bottom: 3rem;
  box-shadow: 0 10px 30px rgba(0,0,0,0.05);
  position: relative;
  overflow: hidden;
}

.content-section::after {
  content: '';
  position: absolute;
  top: 0;
  right: 0;
  width: 100px;
  height: 100px;
  background: radial-gradient(circle, var(--accent) 0%, transparent 70%);
  opacity: 0.1;
}

h2 {
  font-family: 'Montserrat', sans-serif;
  color: var(--primary);
  margin-bottom: 1.5rem;
  font-size: 1.8rem;
  position: relative;
  padding-bottom: 0.5rem;
}

h2::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 50px;
  height: 3px;
  background: linear-gradient(to right, var(--primary), var(--secondary));
}

h3 {
  font-family: 'Montserrat', sans-serif;
  color: var(--secondary);
  margin: 2rem 0 1rem;
  font-size: 1.4rem;
}

p {
  margin-bottom: 1.5rem;
}

.img-container {
  display: flex;
  flex-wrap: wrap;
  gap: 1.5rem;
  margin: 2rem 0;
  justify-content: center;
}

.img-container img {
  width: 100%;
  max-width: 320px;
  height: auto;
  border-radius: 10px;
  box-shadow: 0 10px 20px rgba(0,0,0,0.1);
  transition: all 0.3s ease;
}

.img-container img:hover {
  transform: scale(1.03);
  box-shadow: 0 15px 30px rgba(0,0,0,0.15);
}

pre {
  background: #2A2A3C;
  color: #f8f8f2;
  padding: 1.5rem;
  border-radius: 8px;
  overflow-x: auto;
  margin: 2rem 0;
  font-family: 'Roboto Mono', monospace;
  font-size: 0.9rem;
  line-height: 1.5;
  position: relative;
}

pre::before {
  content: 'CSS';
  position: absolute;
  top: 0;
  left: 0;
  background: var(--accent);
  color: white;
  padding: 0.2rem 0.8rem;
  font-size: 0.8rem;
  border-radius: 0 0 5px 0;
}

code {
  font-family: 'Roboto Mono', monospace;
  background: rgba(0,0,0,0.05);
  padding: 0.2rem 0.4rem;
  border-radius: 3px;
  font-size: 0.9rem;
}

table {
  width: 100%;
  border-collapse: collapse;
  margin: 2rem 0;
  background: white;
  box-shadow: 0 5px 15px rgba(0,0,0,0.05);
  border-radius: 8px;
  overflow: hidden;
}

th, td {
  padding: 1rem;
  text-align: left;
  border-bottom: 1px solid #eee;
}

th {
  background: linear-gradient(to right, var(--primary), var(--secondary));
  color: white;
  font-family: 'Montserrat', sans-serif;
}

tr:hover {
  background: rgba(0,0,0,0.02);
}

.footer {
  text-align: center;
  padding: 2rem;
  background: linear-gradient(45deg, var(--dark), #1a1a2e);
  color: white;
  margin-top: 3rem;
}

.footer p {
  margin-bottom: 0;
}

@media (max-width: 768px) {
  .header h1 {
    font-size: 2rem;
  }
  
  .content-section {
    padding: 2rem;
  }
  
  .nav-tabs {
    flex-direction: column;
    align-items: center;
  }
  
  .img-container img {
    max-width: 100%;
  }
}

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

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

/* Card styles */
.card {
  background: white;
  border-radius: 15px;
  padding: 2rem;
  margin-bottom: 2rem;
  box-shadow: 0 10px 30px rgba(0,0,0,0.05);
  transition: all 0.3s ease;
}

.card:hover {
  transform: translateY(-5px);
  box-shadow: 0 15px 40px rgba(0,0,0,0.1);
}

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

.card p {
  margin-bottom: 1rem;
}