:root{--primary: #0ea5e9;--primary-dark: #0284c7;--surface: #1e293b;--surface-hover: #334155;--bg: #0f172a;--bg-secondary: #1a2332;--text: #e2e8f0;--text-muted: #94a3b8;--text-dim: #64748b;--border: #334155;--danger: #ef4444;--success: #22c55e;--mine-bg: #0ea5e9;--other-bg: #334155;--badge-bg: #ef4444;--input-bg: #1e293b;--scrollbar-bg: #1e293b;--scrollbar-thumb: #475569}*{margin:0;padding:0;box-sizing:border-box}body{font-family:-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,sans-serif;background:var(--bg);color:var(--text);height:100vh;overflow:hidden}#app{height:100vh;display:flex;flex-direction:column}::-webkit-scrollbar{width:6px}::-webkit-scrollbar-track{background:transparent}::-webkit-scrollbar-thumb{background:var(--scrollbar-thumb);border-radius:3px}.login-container{display:flex;align-items:center;justify-content:center;height:100vh;background:var(--bg)}.login-card{background:var(--surface);border-radius:16px;padding:40px;width:100%;max-width:400px;box-shadow:0 25px 50px -12px #00000080}.login-card h1{font-size:24px;margin-bottom:8px;color:var(--text)}.login-card p{color:var(--text-muted);margin-bottom:24px;font-size:14px}.form-group{margin-bottom:16px}.form-group label{display:block;font-size:13px;color:var(--text-muted);margin-bottom:6px}.form-group input{width:100%;padding:12px 16px;background:var(--bg);border:1px solid var(--border);border-radius:8px;color:var(--text);font-size:15px;outline:none;transition:border-color .2s}.form-group input:focus{border-color:var(--primary)}.btn{display:inline-flex;align-items:center;justify-content:center;gap:8px;padding:12px 24px;border:none;border-radius:8px;font-size:15px;font-weight:600;cursor:pointer;transition:all .2s;width:100%}.btn-primary{background:var(--primary);color:#fff}.btn-primary:hover{background:var(--primary-dark)}.btn-primary:disabled{opacity:.5;cursor:not-allowed}.error-msg{background:#ef44441a;color:var(--danger);padding:10px 14px;border-radius:8px;font-size:13px;margin-bottom:16px;display:none}.error-msg.visible{display:block}.chat-layout{display:flex;height:100vh;overflow:hidden}.sidebar{width:320px;min-width:320px;background:var(--bg-secondary);border-right:1px solid var(--border);display:flex;flex-direction:column;overflow:hidden}.sidebar-header{padding:16px;border-bottom:1px solid var(--border);display:flex;align-items:center;justify-content:space-between}.sidebar-header h2{font-size:18px;font-weight:700}.sidebar-header .user-info{display:flex;align-items:center;gap:8px;font-size:13px;color:var(--text-muted)}.sidebar-actions{padding:12px 16px;border-bottom:1px solid var(--border);display:flex;gap:8px}.sidebar-actions button{flex:1;padding:8px;border:1px solid var(--border);border-radius:8px;background:transparent;color:var(--text-muted);font-size:12px;cursor:pointer;transition:all .2s}.sidebar-actions button:hover{background:var(--surface);color:var(--text)}.room-list{flex:1;overflow-y:auto;padding:8px}.room-section-title{font-size:11px;font-weight:700;text-transform:uppercase;color:var(--text-dim);padding:12px 8px 6px;letter-spacing:.05em}.room-item{display:flex;align-items:center;gap:12px;padding:12px;border-radius:10px;cursor:pointer;transition:background .15s;position:relative}.room-item:hover,.room-item.active{background:var(--surface)}.room-avatar{width:44px;height:44px;border-radius:50%;background:var(--primary);display:flex;align-items:center;justify-content:center;font-size:18px;font-weight:700;color:#fff;flex-shrink:0}.room-avatar.group{background:var(--surface-hover);font-size:20px}.room-info{flex:1;min-width:0}.room-name{font-size:14px;font-weight:600;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}.room-preview{font-size:12px;color:var(--text-muted);white-space:nowrap;overflow:hidden;text-overflow:ellipsis;margin-top:2px}.room-meta{display:flex;flex-direction:column;align-items:flex-end;gap:4px;flex-shrink:0}.room-time{font-size:11px;color:var(--text-dim)}.unread-badge{background:var(--badge-bg);color:#fff;font-size:11px;font-weight:700;min-width:20px;height:20px;border-radius:10px;display:flex;align-items:center;justify-content:center;padding:0 6px}.chat-area{flex:1;display:flex;flex-direction:column;background:var(--bg);min-width:0}.chat-header{padding:16px 20px;border-bottom:1px solid var(--border);display:flex;align-items:center;gap:12px}.chat-header .back-btn{display:none;background:none;border:none;color:var(--text);font-size:20px;cursor:pointer;padding:4px}.chat-header-info h3{font-size:16px;font-weight:600}.chat-header-info .online-status{font-size:12px;color:var(--success)}.chat-empty{flex:1;display:flex;align-items:center;justify-content:center;color:var(--text-dim);font-size:16px;flex-direction:column;gap:12px}.chat-empty .icon{font-size:48px;opacity:.5}.messages-container{flex:1;overflow-y:auto;padding:16px 20px;display:flex;flex-direction:column;gap:4px}.msg-group{display:flex;flex-direction:column;gap:2px}.msg-sender-name{font-size:12px;font-weight:600;color:var(--primary);margin-bottom:2px;margin-left:4px}.msg-sender-name.mine{text-align:right;margin-right:4px;margin-left:0;color:var(--text-muted)}.msg-sender-name.clickable{cursor:pointer;text-decoration:underline;text-decoration-color:var(--primary);text-underline-offset:2px}.msg-sender-name.clickable:hover{color:var(--primary-hover)}.msg-bubble{max-width:70%;padding:10px 14px;border-radius:16px;font-size:14px;line-height:1.5;word-wrap:break-word;position:relative;animation:msgIn .2s ease}@keyframes msgIn{0%{opacity:0;transform:translateY(8px)}to{opacity:1;transform:translateY(0)}}.msg-bubble.mine{background:var(--mine-bg);color:#fff;align-self:flex-end;border-bottom-right-radius:4px}.msg-bubble.other{background:var(--other-bg);color:var(--text);align-self:flex-start;border-bottom-left-radius:4px}.msg-bubble img{max-width:240px;max-height:240px;border-radius:8px;display:block;cursor:pointer}.msg-time{font-size:10px;color:#fff9;margin-top:4px;text-align:right}.msg-bubble.other .msg-time{color:var(--text-dim)}.msg-date-separator{text-align:center;color:var(--text-dim);font-size:12px;padding:12px 0}.msg-date-separator span{background:var(--surface);padding:4px 12px;border-radius:12px}.typing-indicator{font-size:12px;color:var(--text-muted);padding:4px 20px 8px;min-height:24px;font-style:italic}.message-input-area{padding:12px 20px;border-top:1px solid var(--border);display:flex;align-items:flex-end;gap:8px}.message-input-area .attach-btn{background:none;border:none;color:var(--text-muted);font-size:22px;cursor:pointer;padding:8px;border-radius:8px;transition:all .15s;flex-shrink:0}.message-input-area .attach-btn:hover{background:var(--surface);color:var(--text)}.message-input-area textarea{flex:1;padding:10px 16px;background:var(--input-bg);border:1px solid var(--border);border-radius:20px;color:var(--text);font-size:14px;font-family:inherit;resize:none;outline:none;max-height:120px;line-height:1.4;transition:border-color .2s}.message-input-area textarea:focus{border-color:var(--primary)}.message-input-area textarea::placeholder{color:var(--text-dim)}.message-input-area .send-btn{background:var(--primary);border:none;color:#fff;width:40px;height:40px;border-radius:50%;cursor:pointer;display:flex;align-items:center;justify-content:center;font-size:18px;transition:all .15s;flex-shrink:0}.message-input-area .send-btn:hover{background:var(--primary-dark)}.message-input-area .send-btn:disabled{opacity:.4;cursor:not-allowed}.modal-overlay{position:fixed;top:0;right:0;bottom:0;left:0;background:#0009;display:flex;align-items:center;justify-content:center;z-index:1000;animation:fadeIn .15s}@keyframes fadeIn{0%{opacity:0}to{opacity:1}}.modal{background:var(--surface);border-radius:16px;width:90%;max-width:400px;max-height:70vh;display:flex;flex-direction:column;overflow:hidden}.modal-header{padding:16px 20px;border-bottom:1px solid var(--border);display:flex;align-items:center;justify-content:space-between}.modal-header h3{font-size:16px}.modal-close{background:none;border:none;color:var(--text-muted);font-size:20px;cursor:pointer}.modal-body{flex:1;overflow-y:auto;padding:8px}.user-item{display:flex;align-items:center;gap:12px;padding:10px 12px;border-radius:8px;cursor:pointer;transition:background .15s}.user-item:hover{background:var(--surface-hover)}.user-item .avatar{width:36px;height:36px;border-radius:50%;background:var(--primary);display:flex;align-items:center;justify-content:center;font-weight:700;color:#fff;font-size:14px}.user-item .name{font-size:14px}.user-item .role{font-size:12px;color:var(--text-muted)}@media(max-width:768px){.sidebar{width:100%;min-width:unset}.chat-area,.chat-layout.room-open .sidebar{display:none}.chat-layout.room-open .chat-area{display:flex}.chat-header .back-btn{display:block}}.spinner{width:24px;height:24px;border:3px solid var(--border);border-top-color:var(--primary);border-radius:50%;animation:spin .6s linear infinite}@keyframes spin{to{transform:rotate(360deg)}}.logout-btn{background:none;border:none;color:var(--text-dim);font-size:13px;cursor:pointer;padding:4px 8px;border-radius:4px}.logout-btn:hover{color:var(--danger)}