.login-container{display:flex;justify-content:center;align-items:center;min-height:100vh}.login-box{background:#fff;padding:40px;border-radius:20px;box-shadow:0 10px 40px #0003;text-align:center;max-width:400px;width:100%}.login-box h1{color:#667eea;margin-bottom:10px;font-size:28px}.login-box p{color:#666;margin-bottom:30px}.username-input{width:100%;padding:15px;border:2px solid #e0e0e0;border-radius:10px;font-size:16px;margin-bottom:20px;transition:border-color .3s}.username-input:focus{outline:none;border-color:#667eea}.login-button{width:100%;padding:15px;background:linear-gradient(135deg,#667eea,#764ba2);color:#fff;border:none;border-radius:10px;font-size:16px;font-weight:700;cursor:pointer;transition:transform .2s}.login-button:hover{transform:translateY(-2px)}.chat-container{display:grid;grid-template-columns:250px 1fr;grid-template-rows:auto 1fr;gap:0;height:calc(100vh - 40px);max-height:calc(100vh - 40px);background:#fff;border-radius:20px;box-shadow:0 10px 40px #0003;overflow:hidden}.chat-header{grid-column:1 / -1;background:linear-gradient(135deg,#667eea,#764ba2);color:#fff;padding:20px 30px;display:flex;justify-content:space-between;align-items:center}.chat-header h1{font-size:24px;font-weight:600}.user-info{display:flex;align-items:center;gap:15px}.current-user{font-weight:500}.logout-button{padding:8px 16px;background:#fff3;color:#fff;border:1px solid rgba(255,255,255,.3);border-radius:8px;cursor:pointer;transition:background .3s}.logout-button:hover{background:#ffffff4d}.users-sidebar{background:#f8f9fa;padding:20px;overflow-y:auto;overflow-x:hidden;border-right:1px solid #e0e0e0;height:100%;min-height:0;display:flex;flex-direction:column}.users-sidebar h3{color:#333;margin-bottom:15px;font-size:16px;flex-shrink:0}.users-list{display:flex;flex-direction:column;gap:8px;flex:1;min-height:0;overflow-y:auto}.user-item{padding:10px;background:#fff;border-radius:8px;font-size:14px;color:#555;transition:all .2s}.user-item.current{background:#667eea;color:#fff;font-weight:600}.chat-main{display:flex;flex-direction:column;height:100%;min-height:0;overflow:hidden}.messages-container{flex:1;overflow-y:auto;overflow-x:hidden;padding:0;background:#f8f9fa;min-height:0;height:100%}.messages-wrapper{padding:20px;min-height:100%;display:flex;flex-direction:column}.empty-state{display:flex;justify-content:center;align-items:center;height:100%;color:#999;font-size:18px}.message-wrapper{margin-bottom:20px;display:flex;flex-direction:column}.message-wrapper.own-message{align-items:flex-end}.message-wrapper:not(.own-message){align-items:flex-start}.message-bubble{max-width:70%;background:#fff;border-radius:15px;padding:15px;box-shadow:0 2px 10px #0000001a}.message-wrapper.own-message .message-bubble{background:linear-gradient(135deg,#667eea,#764ba2);color:#fff}.message-header{display:flex;justify-content:space-between;align-items:center;margin-bottom:8px;font-size:12px;opacity:.8}.message-username{font-weight:600}.message-time{margin-left:10px}.message-text{margin-bottom:12px;line-height:1.5;word-wrap:break-word}.ai-response{margin-top:12px;padding-top:12px;border-top:1px solid rgba(0,0,0,.1)}.message-wrapper.own-message .ai-response{border-top-color:#ffffff4d}.ai-label{font-size:11px;font-weight:600;opacity:.8;display:block;margin-bottom:5px}.ai-text{font-size:14px;line-height:1.5;word-wrap:break-word;font-style:italic}.message-form{display:flex;gap:10px;padding:20px;background:#fff;border-top:1px solid #e0e0e0}.message-input{flex:1;padding:15px;border:2px solid #e0e0e0;border-radius:25px;font-size:16px;transition:border-color .3s}.message-input:focus{outline:none;border-color:#667eea}.send-button{padding:15px 30px;background:linear-gradient(135deg,#667eea,#764ba2);color:#fff;border:none;border-radius:25px;font-size:20px;cursor:pointer;transition:transform .2s;min-width:60px}.send-button:hover:not(:disabled){transform:translateY(-2px)}.send-button:disabled{opacity:.5;cursor:not-allowed}.messages-container::-webkit-scrollbar,.users-sidebar::-webkit-scrollbar{width:10px}.messages-container::-webkit-scrollbar-track,.users-sidebar::-webkit-scrollbar-track{background:#f1f1f1;border-radius:5px}.messages-container::-webkit-scrollbar-thumb,.users-sidebar::-webkit-scrollbar-thumb{background:#888;border-radius:5px;border:2px solid #f1f1f1}.messages-container::-webkit-scrollbar-thumb:hover,.users-sidebar::-webkit-scrollbar-thumb:hover{background:#555}.messages-container,.users-sidebar{scrollbar-width:thin;scrollbar-color:#888 #f1f1f1}@media (max-width: 768px){.chat-container{grid-template-columns:1fr;grid-template-rows:auto auto 1fr}.users-sidebar{border-right:none;border-bottom:1px solid #e0e0e0;max-height:150px}.users-list{flex-direction:row;flex-wrap:wrap}.message-bubble{max-width:85%}}*{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:linear-gradient(135deg,#667eea,#764ba2);min-height:100vh;padding:20px}#root{max-width:1200px;margin:0 auto}