*{margin:0;padding:0;box-sizing:border-box}body{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;background-color:#f5f5f5}.app{display:flex;flex-direction:column;height:100vh;max-width:800px;margin:0 auto;background-color:#fff;box-shadow:0 0 10px #0000001a}.header{padding:20px;border-bottom:1px solid #e0e0e0;background-color:#fff;display:flex;justify-content:space-between;align-items:center}.header h1{font-size:24px;font-weight:600;color:#333}.download-btn{padding:8px 16px;background-color:#fff;color:#333;border:1px solid #d0d0d0;border-radius:6px;font-size:14px;font-weight:500;cursor:pointer;transition:all .2s}.download-btn:hover{background-color:#f5f5f5;border-color:#999}.messages{flex:1;overflow-y:auto;padding:20px;display:flex;flex-direction:column;gap:16px}.message{display:flex;gap:12px;animation:fadeIn .3s ease-in}@keyframes fadeIn{0%{opacity:0;transform:translateY(10px)}to{opacity:1;transform:translateY(0)}}.message-label{font-size:14px;font-weight:600;color:#666;min-width:40px}.message-content{flex:1;padding:12px 16px;border-radius:8px;line-height:1.5;white-space:pre-wrap;word-wrap:break-word}.message.user .message-content{background-color:#f0f0f0;color:#333}.message.assistant .message-content{background-color:#e8f4f8;color:#333}.input-area{display:flex;gap:12px;padding:20px;border-top:1px solid #e0e0e0;background-color:#fff}.input-area input{flex:1;padding:12px 16px;border:1px solid #d0d0d0;border-radius:8px;font-size:14px;outline:none;transition:border-color .2s}.input-area input:focus{border-color:#666}.input-area input:disabled{background-color:#f5f5f5;cursor:not-allowed}.input-area button{padding:12px 24px;background-color:#333;color:#fff;border:none;border-radius:8px;font-size:14px;font-weight:500;cursor:pointer;transition:background-color .2s}.input-area button:hover:not(:disabled){background-color:#555}.input-area button:disabled{background-color:#ccc;cursor:not-allowed}.header-right{display:flex;align-items:center;gap:16px}.usage-bar{display:flex;align-items:center;gap:8px}.usage-label{font-size:13px;color:#666;white-space:nowrap}.usage-progress{width:100px;height:8px;accent-color:#333}