body{margin:0;font-family:-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Oxygen,Ubuntu,Cantarell,Fira Sans,Droid Sans,Helvetica Neue,sans-serif;-webkit-font-smoothing:antialiased;-moz-osx-font-smoothing:grayscale}code{font-family:source-code-pro,Menlo,Monaco,Consolas,Courier New,monospace}*{box-sizing:border-box}#root{width:100%;height:100vh;overflow:hidden}.app-container{display:flex;height:100vh;overflow:hidden;background:#fff}.platform-sidebar{width:60px;background:#2c3e50;border-right:1px solid #e5e5ea;display:flex;flex-direction:column;align-items:center;padding:12px 0;overflow-y:auto}.conversation-list-column{width:320px;background:#fff;border-right:1px solid #e5e5ea;display:flex;flex-direction:column;overflow:hidden}.conversation-list-header{padding:16px;border-bottom:1px solid #e5e5ea;background:#fff}.conversation-list-body{flex:1;overflow-y:auto}.main-content{flex:1;display:flex;flex-direction:column;overflow:hidden;background:#f4f4f5}.main-content-header{height:56px;background:#fff;border-bottom:1px solid #e5e5ea;display:flex;align-items:center;padding:0 16px}.main-content-body{flex:1;overflow-y:auto;padding:16px}.conversation-item{padding:12px 16px;border-bottom:1px solid #e5e5ea;cursor:pointer;transition:background-color .2s}.conversation-item:hover{background:#f4f4f5}.conversation-item.active{background:#e3f2fd}.conversation-item-header{display:flex;justify-content:space-between;align-items:center;margin-bottom:4px}.conversation-item-name{font-weight:600;font-size:14px;color:#000}.conversation-item-time{font-size:12px;color:#8e8e93}.conversation-item-preview{font-size:13px;color:#8e8e93;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}.message-thread{display:flex;flex-direction:column;height:100%}.message-list{flex:1;overflow-y:auto;padding:16px;display:flex;flex-direction:column;gap:8px}.message-item{display:flex;gap:8px;max-width:70%}.message-item.outgoing{align-self:flex-end;flex-direction:row-reverse}.message-bubble{background:#fff;padding:8px 12px;border-radius:12px;box-shadow:0 1px 2px #0000001a}.message-item.outgoing .message-bubble{background:#3390ec;color:#fff}.message-input-area{background:#fff;border-top:1px solid #e5e5ea;padding:12px 16px;display:flex;gap:8px;align-items:center}.message-input{flex:1;border:1px solid #e5e5ea;border-radius:20px;padding:8px 16px;outline:none;font-size:14px}.message-input:focus{border-color:#3390ec}.platform-button{width:44px;height:44px;border-radius:12px;display:flex;align-items:center;justify-content:center;cursor:pointer;transition:all .2s;background:#34495e;color:#fff;border:none;margin-bottom:8px}.platform-button:hover{background:#3390ec;transform:scale(1.05)}.platform-button.active{background:#3390ec;box-shadow:0 0 0 2px #3390ec4d}.loading-spinner{display:flex;align-items:center;justify-content:center;padding:32px}.empty-state{display:flex;flex-direction:column;align-items:center;justify-content:center;padding:48px 24px;text-align:center;color:#8e8e93}.empty-state-icon{font-size:48px;margin-bottom:16px;opacity:.5}.empty-state-title{font-size:18px;font-weight:600;margin-bottom:8px;color:#000}.empty-state-description{font-size:14px}::-webkit-scrollbar{width:6px}::-webkit-scrollbar-track{background:transparent}::-webkit-scrollbar-thumb{background:#c4c4c4;border-radius:3px}::-webkit-scrollbar-thumb:hover{background:#a0a0a0}@media(max-width:768px){.platform-sidebar{width:50px}.conversation-list-column{width:280px}}