* { box-sizing: border-box; }
body { margin: 0; font-family: system-ui, sans-serif; color: #1a1a1a; }
#app { display: flex; height: 100vh; }
#sidebar { width: 260px; border-right: 1px solid #e3e3e3; padding: 12px; overflow-y: auto; background: #fafafa; }
#new-chat { width: 100%; padding: 10px; margin-bottom: 12px; cursor: pointer; border: 1px solid #ccc; border-radius: 8px; background: #fff; }
#conversation-list { list-style: none; padding: 0; margin: 0; }
#conversation-list li { padding: 8px 10px; border-radius: 8px; cursor: pointer; font-size: 14px; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
#conversation-list li:hover { background: #eee; }
#conversation-list li.active { background: #e0ecff; }
#main { flex: 1; display: flex; flex-direction: column; }
#banner { padding: 10px 16px; font-size: 12px; color: #8a2b00; background: #fff6f0; border-bottom: 1px solid #ffd9c2; }
#messages { flex: 1; overflow-y: auto; padding: 16px; display: flex; flex-direction: column; gap: 10px; }
.bubble { max-width: 70%; padding: 10px 14px; border-radius: 14px; line-height: 1.4; white-space: pre-wrap; }
.bubble.user { align-self: flex-end; background: #2f6fed; color: #fff; }
.bubble.assistant { align-self: flex-start; background: #f0f0f0; }
#composer { display: flex; gap: 8px; padding: 12px; border-top: 1px solid #e3e3e3; }
#input { flex: 1; padding: 12px; border: 1px solid #ccc; border-radius: 10px; font-size: 15px; }
#composer button { padding: 0 18px; border: none; border-radius: 10px; background: #2f6fed; color: #fff; cursor: pointer; }
#composer button:disabled { opacity: 0.5; cursor: default; }