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

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  line-height: 1.6;
  color: #2c3e50;
  background-color: #fafafa;
}

header {
  background-color: #fff;
  border-bottom: 1px solid #e5e5e5;
  padding: 1rem 2rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

header h1 {
  font-size: 1.25rem;
  color: #1a5f3f;
}

header nav a {
  margin-left: 1.5rem;
  color: #2c3e50;
  text-decoration: none;
  font-size: 0.95rem;
}

header nav a:hover {
  color: #1a5f3f;
}

main {
  max-width: 800px;
  margin: 0 auto;
  padding: 3rem 2rem;
}

.hero {
  text-align: center;
  padding: 2rem 0;
}

.hero h2 {
  font-size: 2rem;
  margin-bottom: 1rem;
  color: #1a5f3f;
}

.hero p {
  font-size: 1.1rem;
  color: #555;
  margin-bottom: 2rem;
}

.btn {
  display: inline-block;
  background-color: #1a5f3f;
  color: #fff;
  padding: 0.85rem 2rem;
  border: none;
  border-radius: 4px;
  text-decoration: none;
  font-size: 1rem;
  cursor: pointer;
  transition: background-color 0.2s;
}

.btn:hover {
  background-color: #144d32;
}

.chat-box {
  padding: 1.5rem;
  margin-top: 2rem;
}

.messages {
  min-height: 250px;
  margin-bottom: 1rem;
  padding: 1rem;
  background-color: #f9f9f9;
  border-radius: 4px;
}

.chat-form {
  display: flex;
  gap: 0.5rem;
}

.chat-form input {
  flex: 1;
  padding: 0.75rem;
  border: 1px solid #ddd;
  border-radius: 4px;
  font-size: 1rem;
}

.error-page {
  text-align: center;
  padding: 4rem 0;
}

.error-page h2 {
  font-size: 2rem;
  color: #c0392b;
  margin-bottom: 1rem;
}

.error-page p {
  margin-bottom: 2rem;
  color: #555;
}

footer {
  text-align: center;
  padding: 2rem;
  color: #888;
  font-size: 0.9rem;
  border-top: 1px solid #e5e5e5;
  margin-top: 3rem;
}