* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

body {
  background: #0f172a;
  color: #f8fafc;
  min-height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
}

.app-container {
  width: 100%;
  max-width: 800px;
  height: 90vh;
  background: rgba(30, 41, 59, 0.7);
  backdrop-filter: blur(12px);
  border: 1px solid rgba(255, 255, 255, 0.1);
  border-radius: 16px;
  display: flex;
  flex-direction: column;
  overflow: hidden;
  box-shadow: 0 20px 25px -5px rgba(0, 0, 0, 0.5);
}

header {
  padding: 20px;
  background: rgba(15, 23, 42, 0.8);
  border-bottom: 1px solid rgba(255, 255, 255, 0.05);
  text-align: center;
}

header h1 {
  font-size: 1.5rem;
  color: #38bdf8;
}

header p {
  font-size: 0.85rem;
  color: #94a3b8;
}

.chat-messages {
  flex: 1;
  padding: 20px;
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.message {
  padding: 12px 16px;
  border-radius: 12px;
  max-width: 75%;
  line-height: 1.5;
  word-break: break-word;
}

.ai-message {
  background: #334155;
  color: #f8fafc;
  align-self: flex-start;
  border-bottom-left-radius: 2px;
}

.user-message {
  background: #0284c7;
  color: #ffffff;
  align-self: flex-end;
  border-bottom-right-radius: 2px;
}

.input-area {
  padding: 20px;
  background: rgba(15, 23, 42, 0.8);
  border-top: 1px solid rgba(255, 255, 255, 0.05);
  display: flex;
  gap: 12px;
  align-items: center;
}

textarea {
  flex: 1;
  background: #1e293b;
  border: 1px solid rgba(255, 255, 255, 0.1);
  border-radius: 8px;
  padding: 12px;
  color: #f8fafc;
  resize: none;
  max-height: 120px;
  outline: none;
  transition: border-color 0.2s;
}

textarea:focus {
  border-color: #38bdf8;
}

button {
  background: #0284c7;
  color: white;
  border: none;
  padding: 12px 24px;
  border-radius: 8px;
  font-weight: 600;
  cursor: pointer;
  transition: background 0.2s;
}

button:hover {
  background: #0369a1;
}