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

body {
  font-family:'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  line-height:1.6;
  color:#302f2f;
  background:linear-gradient(135deg,#667eea 0%, #764ba2 100%);
  min-height:100vh;
  padding:20px;  
}

.container {
  max-width:900px;
  margin:0 auto;
  background:rgba(255,255,255,0.95);
  border-radius:20px;
  box-shadow:0 20px 40px rgba(0,0,0,0.1);
  backdrop-filter:blur(10px);
  overflow:hidden;
  padding:20px;
}

.back-button {
  background:linear-gradient(45deg,#3498db,#2980b9);
  color:white;
  padding:12px 25px;
  border-radius:25px;
  text-decoration:none;
  margin-bottom:30px;
  display:inline-block;
}

.header {text-align:center; color:rgb(67,64,64);}
.header h1 {
  font-size:3em;
  margin-bottom:10px;
  text-shadow:2px 2px 4px rgba(29,16,44,0.3);
}
.header p {font-size:1.2em; opacity:0.9;}

.content {padding:40px;}

.section {
  margin-bottom:40px;
  padding:30px;
  background:rgba(251,251,251,0.97);
  border-radius:15px;
  border-left:5px solid #4105d7;
  transition:transform 0.3s ease;
}
.section:hover {
  transform:translateY(-5px);
  box-shadow:0 10px 20px rgba(0,0,0,0.1);
}
.section h2 {
  color:#2c3e50;
  margin-bottom:20px;
  font-size:2em;
  display:flex;
  align-items:center;
  gap:10px;
}

.icon {
  width:30px;
  height:30px;
  border-radius:50%;
  display:inline-flex;
  align-items:center;
  justify-content:center;
}

.examples-grid {
  display:grid;
  grid-template-columns:repeat(auto-fit,minmax(300px,1fr));
  gap:20px;
  margin:20px 0;
}
.example-card {
  background:linear-gradient(135deg,#f6f6f6 0%,#ffffff 100%);
  padding:20px;
  border-radius:10px;
  box-shadow:0 5px 15px rgba(0,0,0,0.1);
}
.example-card h4 {color:#2c3e50; margin-bottom:10px;}
.example-card p {margin:5px 0; font-size:1.1em;}

.key-points {
  background:linear-gradient(135deg,#ffecd2 0%,#fcb69f 100%);
  padding:30px;
  border-radius:15px;
  margin:20px 0;
}
.key-points li {
  margin:15px 0;
  padding:15px;
  background:rgba(255,255,255,0.5);
  border-radius:8px;
  border-left:4px solid #ff6b6b;
  font-weight:500;
}

.activity {
  background:linear-gradient(135deg,#d299c2 0%,#fef9d7 100%);
  padding:30px;
  border-radius:15px;
  margin:20px 0;
}
.question {
  background:rgba(255,255,255,0.7);
  padding:15px;
  margin:15px 0;
  border-radius:8px;
  border-left:4px solid #9b59b6;
}
.input-field {
  width:100%;
  padding:10px;
  margin:10px 0;
  border:2px solid #ddd;
  border-radius:5px;
  font-size:1em;
}
.check-btn {
  background:linear-gradient(135deg,#667eea 0%,#764ba2 100%);
  color:white;
  border:none;
  padding:12px 25px;
  border-radius:25px;
  cursor:pointer;
  font-size:1em;
  transition:transform 0.2s ease;
}
.check-btn:hover {transform:scale(1.05);}

.result {
  margin:10px 0;
  padding:10px;
  border-radius:5px;
  font-weight:bold;
}
.correct {
  background:#d4edda;
  color:#155724;
  border:1px solid #c3e6cb;
}
.incorrect {
  background:#f8d7da;
  color:#721c24;
  border:1px solid #f5c6cb;
}