:root {
  --bg-color: #0b0e14;
  --glass-bg: rgba(20, 25, 35, 0.6);
  --accent-color: #6366f1;
  --accent-gradient: linear-gradient(135deg, #6366f1 0%, #a855f7 100%);
  --text-primary: #f8fafc;
  --text-secondary: #94a3b8;
  --border-color: rgba(255, 255, 255, 0.1);
  --error-color: #ef4444;
}

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

body {
  font-family: 'Inter', system-ui, -apple-system, sans-serif;
  background-color: var(--bg-color);
  color: var(--text-primary);
  height: 100vh;
  overflow: hidden;
  display: flex;
  justify-content: center;
  align-items: center;
  background-image: 
    radial-gradient(at 0% 0%, rgba(99, 102, 241, 0.15) 0px, transparent 50%),
    radial-gradient(at 100% 100%, rgba(168, 85, 247, 0.15) 0px, transparent 50%);
}

/* Auth Overlay */
#auth-overlay {
  position: fixed;
  inset: 0;
  background: var(--bg-color);
  z-index: 1000;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  transition: opacity 0.5s ease, transform 0.5s ease;
}

.auth-card {
  background: var(--glass-bg);
  backdrop-filter: blur(20px);
  padding: 3rem;
  border-radius: 24px;
  border: 1px solid var(--border-color);
  text-align: center;
  width: 90%;
  max-width: 400px;
  box-shadow: 0 20px 50px rgba(0,0,0,0.5);
}

.logo {
  font-size: 2rem;
  font-weight: 800;
  background: var(--accent-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  margin-bottom: 1rem;
}

input {
  width: 100%;
  padding: 12px 16px;
  background: rgba(255,255,255,0.05);
  border: 1px solid var(--border-color);
  border-radius: 12px;
  color: white;
  margin: 1rem 0;
  outline: none;
  font-size: 1rem;
}

input:focus {
  border-color: var(--accent-color);
  box-shadow: 0 0 0 2px rgba(99, 102, 241, 0.2);
}

button {
  width: 100%;
  padding: 12px;
  background: var(--accent-gradient);
  border: none;
  border-radius: 12px;
  color: white;
  font-weight: 600;
  cursor: pointer;
  transition: transform 0.2s ease, opacity 0.2s ease;
}

button:hover {
  transform: translateY(-2px);
  opacity: 0.9;
}

/* Chat Layout */
#main-app {
  display: none;
  width: 100%;
  max-width: 1200px;
  height: 90vh;
  background: var(--glass-bg);
  backdrop-filter: blur(20px);
  border-radius: 24px;
  border: 1px solid var(--border-color);
  flex-direction: column;
  overflow: hidden;
  box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.5);
}

header {
  padding: 1.5rem 2rem;
  border-bottom: 1px solid var(--border-color);
  display: flex;
  justify-content: space-between;
  align-items: center;
}

#chat-container {
  flex: 1;
  overflow-y: auto;
  padding: 2rem;
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

.message {
  max-width: 80%;
  padding: 1rem 1.5rem;
  border-radius: 18px;
  line-height: 1.6;
  animation: slideUp 0.3s ease;
}

.user-message {
  align-self: flex-end;
  background: var(--accent-gradient);
  color: white;
  border-bottom-right-radius: 4px;
}

.bot-message {
  align-self: flex-start;
  background: rgba(255,255,255,0.05);
  border: 1px solid var(--border-color);
  border-bottom-left-radius: 4px;
}

.input-area {
  padding: 1.5rem 2rem;
  background: rgba(0,0,0,0.2);
  display: flex;
  gap: 1rem;
}

#user-input {
  flex: 1;
  margin: 0;
}

@keyframes slideUp {
  from { opacity: 0; transform: translateY(10px); }
  to { opacity: 1; transform: translateY(0); }
}