:root {
  --i1-primary: #1a73e8;
  --i1-bg: #181b20;
  --i1-card: #23262c;
  --i1-text: #e6eaf0;
  --i1-secondary: #2e8b57;
  --i1-accent: #fbbc04;
  --i1-user: #2e8b57;
  --i1-ai: #1a73e8;
  --i1-border: #33363d;
}

body {
  background: var(--i1-bg);
  color: var(--i1-text);
  font-family: 'Segoe UI', 'Roboto', 'Arial', sans-serif;
  margin: 0;
  min-height: 100vh;
}

.i1-app {
  max-width: 500px;
  margin: 32px auto;
  background: var(--i1-card);
  border-radius: 16px;
  box-shadow: 0 6px 24px rgba(0,0,0,0.25);
  display: flex;
  flex-direction: column;
  min-height: 80vh;
}

header {
  padding: 1.5em 1.5em 0.5em 1.5em;
  border-bottom: 1px solid var(--i1-border);
}

.i1-logo {
  font-size: 1.5em;
  font-weight: bold;
  color: var(--i1-primary);
  letter-spacing: 1px;
  display: flex;
  align-items: center;
  gap: 0.5em;
}

.i1-logo span {
  color: var(--i1-accent);
}

main {
  flex: 1;
  display: flex;
  flex-direction: column;
  padding: 0 1.5em;
  overflow: hidden;
}

.chat-history {
  flex: 1;
  overflow-y: auto;
  padding: 1em 0;
  margin-bottom: 1em;
}

.message {
  display: flex;
  align-items: flex-start;
  margin-bottom: 1.2em;
}

.message .avatar {
  font-size: 1.7em;
  margin-right: 0.7em;
  margin-top: -0.2em;
}

.message.user .avatar {
  color: var(--i1-user);
}

.message.ai .avatar {
  color: var(--i1-ai);
}

.message .bubble {
  background: var(--i1-border);
  color: var(--i1-text);
  border-radius: 12px;
  padding: 0.9em 1.1em;
  font-size: 1em;
  max-width: 80%;
  word-break: break-word;
  line-height: 1.5;
  border: 1.5px solid transparent;
}

.message.user .bubble {
  background: var(--i1-user);
  color: #fff;
  align-self: flex-end;
  border: 1.5px solid var(--i1-user);
}

.message.ai .bubble {
  background: var(--i1-ai);
  color: #fff;
  border: 1.5px solid var(--i1-ai);
}

#chat-form {
  display: flex;
  gap: 0.5em;
  padding-bottom: 1em;
}

#user-input {
  flex: 1;
  resize: none;
  border-radius: 8px;
  border: 1px solid var(--i1-border);
  padding: 0.7em 1em;
  font-size: 1em;
  background: var(--i1-bg);
  color: var(--i1-text);
  outline: none;
  transition: border 0.2s;
}

#user-input:focus {
  border-color: var(--i1-primary);
}

#send-btn {
  background: var(--i1-primary);
  color: #fff;
  border: none;
  border-radius: 8px;
  padding: 0.7em 1.3em;
  font-size: 1em;
  font-weight: bold;
  cursor: pointer;
  transition: background 0.2s;
}

#send-btn:disabled {
  background: #444a;
  cursor: not-allowed;
}

#loading-indicator {
  color: var(--i1-accent);
  font-size: 1em;
  padding: 0.5em 0;
  text-align: center;
}

footer {
  padding: 1em 1.5em;
  border-top: 1px solid var(--i1-border);
  font-size: 0.95em;
  color: #aaa;
  text-align: center;
  background: var(--i1-card);
  border-radius: 0 0 16px 16px;
}

@media (max-width: 600px) {
  .i1-app {
    max-width: 100vw;
    margin: 0;
    border-radius: 0;
    min-height: 100vh;
  }
  main {
    padding: 0 0.5em;
  }
  footer, header {
    padding-left: 0.7em;
    padding-right: 0.7em;
  }
}