*{margin:0;padding:0;box-sizing:border-box}body{font-family:-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,sans-serif;background-color:#f5f5f5;color:#333}.app{height:100vh;display:flex;flex-direction:column}.app-header{background:#2c3e50;color:#fff;padding:1rem;display:flex;justify-content:space-between;align-items:center;box-shadow:0 2px 4px #0000001a}.connection-status{display:flex;align-items:center;gap:1rem}.status-indicator{font-size:.9rem}.status-indicator.connected{color:#2ecc71}.status-indicator.disconnected{color:#e74c3c}.logout-btn{background:#e74c3c;color:#fff;border:none;padding:.5rem 1rem;border-radius:4px;cursor:pointer}.logout-btn:hover{background:#c0392b}.app-main{flex:1;display:flex;overflow:hidden}.login-container{display:flex;justify-content:center;align-items:center;flex:1;padding:2rem}.login-card{background:#fff;padding:2rem;border-radius:8px;box-shadow:0 4px 6px #0000001a;max-width:400px;width:100%}.login-form{display:flex;flex-direction:column;gap:1rem;margin-bottom:2rem}.username-input{padding:.75rem;border:1px solid #ddd;border-radius:4px;font-size:1rem}.login-button{background:#3498db;color:#fff;border:none;padding:.75rem;border-radius:4px;font-size:1rem;cursor:pointer}.login-button:hover{background:#2980b9}.login-features ul{list-style:none;padding-left:0}.login-features li{padding:.25rem 0;color:#666}.chat-room{display:flex;flex:1;height:100%}.chat-sidebar{width:250px;background:#fff;border-right:1px solid #ddd;display:flex;flex-direction:column}.chat-main{flex:1;display:flex;flex-direction:column}.chat-header{background:#fff;padding:1rem;border-bottom:1px solid #ddd;display:flex;justify-content:space-between;align-items:center}.room-users{color:#666;font-size:.9rem}.room-selector{padding:1rem;border-bottom:1px solid #ddd}.rooms{display:flex;flex-direction:column;gap:.5rem}.room-button{display:flex;justify-content:space-between;align-items:center;padding:.75rem;border:none;background:none;text-align:left;cursor:pointer;border-radius:4px;transition:background-color .2s}.room-button:hover{background:#f8f9fa}.room-button.active{background:#3498db;color:#fff}.unread-badge{background:#e74c3c;color:#fff;border-radius:10px;padding:.2rem .5rem;font-size:.8rem}.user-list{flex:1;padding:1rem;overflow-y:auto}.users{display:flex;flex-direction:column;gap:.5rem}.user-item{display:flex;flex-direction:column;padding:.5rem;border-radius:4px;transition:background-color .2s}.user-item:hover{background:#f8f9fa}.user-info{display:flex;align-items:center;gap:.5rem}.user-status{width:8px;height:8px;border-radius:50%}.user-status.online{background:#2ecc71}.username{font-weight:500}.current-user{background:#e8f4fd}.private-message-btn{background:none;border:none;cursor:pointer;padding:.25rem;border-radius:4px}.private-message-btn:hover{background:#e9ecef}.private-message-input{display:flex;gap:.5rem;margin-top:.5rem}.private-message-input input{flex:1;padding:.25rem;border:1px solid #ddd;border-radius:4px}.private-message-input button{padding:.25rem .5rem;border:none;border-radius:4px;cursor:pointer;font-size:.8rem}.message-list{flex:1;overflow-y:auto;padding:1rem;display:flex;flex-direction:column;gap:1rem}.message{display:flex;flex-direction:column;max-width:70%;animation:messageAppear .3s ease-out}@keyframes messageAppear{0%{opacity:0;transform:translateY(10px)}to{opacity:1;transform:translateY(0)}}.own-message{align-self:flex-end;align-items:flex-end}.other-message{align-self:flex-start;align-items:flex-start}.system-message{align-self:center;align-items:center;color:#666;font-style:italic;max-width:100%}.message-sender{font-weight:600;font-size:.9rem;margin-bottom:.25rem;color:#555}.message-content-wrapper{position:relative}.message-content{background:#fff;padding:.75rem 1rem;border-radius:18px;box-shadow:0 1px 2px #0000001a;word-wrap:break-word}.own-message .message-content{background:#3498db;color:#fff}.system-message .message-content{background:none;box-shadow:none;padding:.5rem;color:#666}.message-reactions{display:flex;gap:.5rem;margin-top:.5rem;flex-wrap:wrap}.reaction{background:#fff;border:1px solid #ddd;border-radius:12px;padding:.25rem .5rem;font-size:.8rem}.message-actions{position:absolute;top:-10px;right:-10px;opacity:0;transition:opacity .2s}.message-content-wrapper:hover .message-actions{opacity:1}.reaction-button{background:#fff;border:1px solid #ddd;border-radius:50%;width:24px;height:24px;cursor:pointer;font-size:.8rem}.reaction-picker{position:absolute;top:100%;right:0;background:#fff;border:1px solid #ddd;border-radius:8px;padding:.5rem;display:flex;gap:.25rem;box-shadow:0 2px 8px #0000001a;z-index:10}.reaction-option{background:none;border:none;cursor:pointer;font-size:1rem;padding:.25rem;border-radius:4px}.reaction-option:hover{background:#f8f9fa}.message-time{font-size:.75rem;color:#999;margin-top:.25rem}.typing-indicator{display:flex;align-items:center;gap:.5rem;color:#666;font-style:italic;padding:.5rem 1rem}.typing-dots{display:flex;gap:2px}.typing-dots span{width:4px;height:4px;border-radius:50%;background:#999;animation:typing 1.4s infinite ease-in-out}.typing-dots span:nth-child(1){animation-delay:-.32s}.typing-dots span:nth-child(2){animation-delay:-.16s}@keyframes typing{0%,80%,to{transform:scale(0)}40%{transform:scale(1)}}.message-input-form{padding:1rem;background:#fff;border-top:1px solid #ddd}.message-input-wrapper{display:flex;gap:.5rem;align-items:flex-end}.message-input{flex:1;padding:.75rem;border:1px solid #ddd;border-radius:20px;resize:none;font-family:inherit;font-size:1rem;max-height:120px;min-height:40px}.message-input:focus{outline:none;border-color:#3498db}.send-button{background:#3498db;color:#fff;border:none;padding:.75rem 1.5rem;border-radius:20px;cursor:pointer;font-size:1rem}.send-button:hover:not(:disabled){background:#2980b9}.send-button:disabled{background:#bdc3c7;cursor:not-allowed}.notification-center{position:fixed;bottom:2rem;right:2rem;z-index:1000}.notification-button{background:#fff;border:1px solid #ddd;border-radius:50%;width:50px;height:50px;cursor:pointer;font-size:1.2rem;position:relative;box-shadow:0 2px 8px #0000001a}.notification-badge{position:absolute;top:-5px;right:-5px;background:#e74c3c;color:#fff;border-radius:50%;width:20px;height:20px;font-size:.7rem;display:flex;align-items:center;justify-content:center}.notification-dropdown{position:absolute;bottom:100%;right:0;width:300px;background:#fff;border:1px solid #ddd;border-radius:8px;box-shadow:0 4px 12px #0000001a;margin-bottom:.5rem}.notification-header{display:flex;justify-content:space-between;align-items:center;padding:1rem;border-bottom:1px solid #ddd}.notification-header h4{margin:0}.notification-header button{background:none;border:none;cursor:pointer;font-size:1rem}.notification-list{max-height:300px;overflow-y:auto}.notification-item{padding:.75rem 1rem;border-bottom:1px solid #f0f0f0}.notification-item:last-child{border-bottom:none}.notification-item.unread{background:#f8f9fa}.notification-message{margin-bottom:.25rem}.notification-time{font-size:.8rem;color:#999}.no-notifications{padding:2rem;text-align:center;color:#666}@media(max-width:768px){.chat-sidebar{width:200px}.message{max-width:85%}.notification-dropdown{width:280px;right:-50px}}@media(max-width:480px){.chat-room{flex-direction:column}.chat-sidebar{width:100%;height:150px;flex-direction:row;overflow-x:auto}.room-selector,.user-list{flex:1;min-width:150px}.message{max-width:95%}.app-header{padding:.5rem}.app-header h1{font-size:1.2rem}}