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

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Hiragino Sans', 'Noto Sans CJK JP', sans-serif;
  background-color: #f5f5f5;
  color: #333;
  min-height: 100vh;
}

.container {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
  max-width: 1200px;
  margin: 0 auto;
  padding: 20px;
}

.header {
  text-align: center;
  padding: 30px 0;
}

.header h1 {
  font-size: 2.5rem;
  color: #2c3e50;
  margin-bottom: 10px;
}

.subtitle {
  font-size: 1.2rem;
  color: #7f8c8d;
}

.main {
  flex: 1;
  display: flex;
  justify-content: center;
  align-items: center;
  padding: 20px 0;
}

.chat-container {
  width: 100%;
  max-width: 800px;
  height: 600px;
  background-color: #fff;
  border-radius: 12px;
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.1);
  overflow: hidden;
}

.placeholder {
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  height: 100%;
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  color: #fff;
}

.placeholder p {
  font-size: 1.5rem;
  font-weight: bold;
}

.placeholder-note {
  margin-top: 10px;
  font-size: 1rem !important;
  font-weight: normal !important;
  opacity: 0.8;
}

.footer {
  text-align: center;
  padding: 20px 0;
  color: #95a5a6;
  font-size: 0.9rem;
}

/* Responsive */
@media (max-width: 768px) {
  .header h1 {
    font-size: 1.8rem;
  }

  .chat-container {
    height: 500px;
  }

  .container {
    padding: 10px;
  }
}