:root{--bg-primary: #1a1a2e;--bg-secondary: #16213e;--bg-card: #0f3460;--bg-input: #1a1a3e;--accent: #e94560;--accent-hover: #ff6b81;--text-primary: #eee;--text-secondary: #aab;--text-muted: #667;--border: #2a2a4e;--success: #4ecdc4;--warning: #ffe66d;--radius: 12px;--radius-sm: 8px}*{margin:0;padding:0;box-sizing:border-box}html,body,#root{height:100%;font-family:-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,sans-serif;background:var(--bg-primary);color:var(--text-primary);-webkit-font-smoothing:antialiased}.app{display:flex;flex-direction:column;height:100%;max-width:900px;margin:0 auto}.loading-screen{display:flex;align-items:center;justify-content:center}.spinner{width:40px;height:40px;border:3px solid var(--border);border-top-color:var(--accent);border-radius:50%;animation:spin .8s linear infinite}@keyframes spin{to{transform:rotate(360deg)}}.navbar{display:flex;align-items:center;gap:4px;padding:8px 12px;background:var(--bg-secondary);border-bottom:1px solid var(--border);overflow-x:auto;flex-shrink:0}.navbar a,.navbar button.nav-link{padding:6px 12px;border-radius:var(--radius-sm);color:var(--text-secondary);text-decoration:none;font-size:14px;white-space:nowrap;background:none;border:none;cursor:pointer;font-family:inherit}.navbar a:hover,.navbar button.nav-link:hover{color:var(--text-primary);background:var(--bg-card)}.navbar a.active{color:var(--accent);background:#e945601a}.nav-spacer{flex:1}.nav-user{font-size:12px;color:var(--text-muted);padding:0 8px}.main-content{flex:1;display:flex;flex-direction:column;overflow:hidden}.login-page{display:flex;align-items:center;justify-content:center;height:100%;padding:20px}.login-card{background:var(--bg-secondary);border:1px solid var(--border);border-radius:var(--radius);padding:32px;width:100%;max-width:380px}.login-card h1{font-size:24px;margin-bottom:4px;color:var(--accent)}.login-card p.subtitle{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-secondary);margin-bottom:4px}.form-group input,.form-input{width:100%;padding:10px 12px;background:var(--bg-input);border:1px solid var(--border);border-radius:var(--radius-sm);color:var(--text-primary);font-size:15px;outline:none;font-family:inherit}.form-group input:focus,.form-input:focus{border-color:var(--accent)}.btn{padding:10px 20px;border:none;border-radius:var(--radius-sm);font-size:15px;font-weight:500;cursor:pointer;font-family:inherit;transition:background .15s}.btn-primary{background:var(--accent);color:#fff;width:100%}.btn-primary:hover{background:var(--accent-hover)}.btn-primary:disabled{opacity:.5;cursor:not-allowed}.btn-secondary{background:var(--bg-card);color:var(--text-primary)}.btn-secondary:hover{background:#1a4a7a}.btn-danger{background:#c0392b;color:#fff}.btn-danger:hover{background:#e74c3c}.btn-sm{padding:6px 12px;font-size:13px}.error-msg{color:var(--accent);font-size:13px;margin-top:8px}.link-btn{background:none;border:none;color:var(--accent);cursor:pointer;font-size:13px;padding:0;font-family:inherit}.link-btn:hover{text-decoration:underline}.chat-page{display:flex;flex-direction:column;height:100%}.chat-header{padding:8px 16px;display:flex;align-items:center;gap:8px;border-bottom:1px solid var(--border);flex-shrink:0}.chat-header .mode-label{font-size:13px;color:var(--text-muted);text-transform:uppercase;letter-spacing:.5px}.new-session-btn{margin-left:auto;font-size:12px}.messages{flex:1;overflow-y:auto;padding:16px;display:flex;flex-direction:column;gap:12px}.message{max-width:85%;padding:10px 14px;border-radius:var(--radius);font-size:15px;line-height:1.5;word-wrap:break-word}.message-user{align-self:flex-end;background:var(--accent);color:#fff;border-bottom-right-radius:4px}.message-assistant{align-self:flex-start;background:var(--bg-card);color:var(--text-primary);border-bottom-left-radius:4px}.message-system{align-self:center;background:none;color:var(--text-muted);font-size:13px;font-style:italic}.message-assistant .speak-btn{display:inline-block;margin-left:6px;background:none;border:none;cursor:pointer;font-size:16px;vertical-align:middle;opacity:.7;filter:grayscale(1) brightness(2)}.message-assistant .speak-btn:hover{opacity:1}.typing-indicator{align-self:flex-start;color:var(--text-muted);font-size:13px;padding:8px 14px}.typing-indicator span{animation:blink 1.4s infinite both}.typing-indicator span:nth-child(2){animation-delay:.2s}.typing-indicator span:nth-child(3){animation-delay:.4s}@keyframes blink{0%,80%,to{opacity:0}40%{opacity:1}}.chat-input-area{padding:12px 16px;border-top:1px solid var(--border);display:flex;gap:8px;align-items:flex-end;flex-shrink:0}.chat-input-area textarea{flex:1;padding:10px 12px;background:var(--bg-input);border:1px solid var(--border);border-radius:var(--radius-sm);color:var(--text-primary);font-size:15px;resize:none;outline:none;min-height:42px;max-height:120px;font-family:inherit;line-height:1.4}.chat-input-area textarea:focus{border-color:var(--accent)}.lang-toggle{padding:4px 8px;border-radius:var(--radius-sm);border:1px solid var(--border);background:var(--bg-input);color:var(--accent);font-size:12px;font-weight:600;cursor:pointer;font-family:inherit;min-width:32px}.lang-toggle:hover{background:var(--bg-card)}.mic-btn{width:42px;height:42px;border-radius:50%;border:none;background:var(--bg-card);color:var(--text-secondary);font-size:20px;cursor:pointer;display:flex;align-items:center;justify-content:center;flex-shrink:0}.mic-btn.recording{background:var(--accent);color:#fff;animation:pulse 1.5s infinite}.mic-btn.transcribing{background:var(--warning);color:var(--bg-primary);opacity:.8;cursor:wait}@keyframes pulse{0%,to{box-shadow:0 0 #e9456066}50%{box-shadow:0 0 0 10px #e9456000}}.send-btn{width:42px;height:42px;border-radius:50%;border:none;background:var(--accent);color:#fff;font-size:18px;cursor:pointer;display:flex;align-items:center;justify-content:center;flex-shrink:0}.send-btn:disabled{opacity:.4;cursor:not-allowed}.admin-page{padding:20px 16px;overflow-y:auto;height:100%}.admin-page h2{font-size:20px;margin-bottom:16px;color:var(--accent)}.admin-page h3{font-size:16px;margin:20px 0 10px}.admin-section{background:var(--bg-secondary);border:1px solid var(--border);border-radius:var(--radius);padding:16px;margin-bottom:16px}.user-list{list-style:none}.user-list li{display:flex;align-items:center;justify-content:space-between;padding:8px 0;border-bottom:1px solid var(--border);gap:8px}.user-list li:last-child{border-bottom:none}.user-info{flex:1}.user-info .username{font-weight:500}.user-info .role{font-size:12px;color:var(--text-muted);margin-left:8px}.user-actions{display:flex;gap:6px}.toggle-row{display:flex;align-items:center;justify-content:space-between;padding:8px 0}.toggle-switch{position:relative;width:44px;height:24px}.toggle-switch input{opacity:0;width:0;height:0}.toggle-slider{position:absolute;cursor:pointer;top:0;right:0;bottom:0;left:0;background:var(--border);border-radius:24px;transition:.2s}.toggle-slider:before{content:"";position:absolute;height:18px;width:18px;left:3px;bottom:3px;background:#fff;border-radius:50%;transition:.2s}.toggle-switch input:checked+.toggle-slider{background:var(--success)}.toggle-switch input:checked+.toggle-slider:before{transform:translate(20px)}.create-user-form{display:flex;gap:8px;flex-wrap:wrap;align-items:flex-end}.create-user-form input{flex:1;min-width:120px}.modal-overlay{position:fixed;top:0;right:0;bottom:0;left:0;background:#000000b3;display:flex;align-items:center;justify-content:center;z-index:100;padding:20px}.modal{background:var(--bg-secondary);border:1px solid var(--border);border-radius:var(--radius);width:100%;max-width:700px;max-height:90vh;display:flex;flex-direction:column}.modal-header{display:flex;align-items:center;justify-content:space-between;padding:16px;border-bottom:1px solid var(--border)}.modal-header h3{margin:0}.modal-body{flex:1;overflow-y:auto;padding:16px}.modal-body textarea{width:100%;min-height:200px;padding:12px;background:var(--bg-input);border:1px solid var(--border);border-radius:var(--radius-sm);color:var(--text-primary);font-size:14px;font-family:Consolas,Monaco,monospace;resize:vertical;outline:none;line-height:1.5}.modal-body textarea:focus{border-color:var(--accent)}.modal-footer{padding:12px 16px;border-top:1px solid var(--border);display:flex;gap:8px;justify-content:flex-end}.file-list{list-style:none}.file-list li{display:flex;align-items:center;justify-content:space-between;padding:6px 0;font-size:14px}.file-size{color:var(--text-muted);font-size:12px;margin-left:8px}.admin-chat{border:1px solid var(--border);border-radius:var(--radius-sm);margin-top:12px}.admin-chat .messages{max-height:300px;min-height:150px;padding:12px}.admin-chat .chat-input-area{padding:8px 12px}.tabs{display:flex;gap:0;border-bottom:1px solid var(--border);margin-bottom:16px}.tab{padding:8px 16px;background:none;border:none;color:var(--text-muted);cursor:pointer;font-size:14px;border-bottom:2px solid transparent;font-family:inherit}.tab.active{color:var(--accent);border-bottom-color:var(--accent)}.flashcard-page,.quiz-page,.shadow-page{display:flex;flex-direction:column;height:100%}.card-container{flex:1;display:flex;align-items:center;justify-content:center;padding:20px}.flashcard{width:100%;max-width:400px;min-height:220px;background:var(--bg-card);border:1px solid var(--border);border-radius:var(--radius);display:flex;align-items:center;justify-content:center;padding:32px;cursor:pointer;text-align:center;font-size:24px;line-height:1.4;transition:transform .3s;-webkit-user-select:none;user-select:none}.flashcard:hover{transform:scale(1.02)}.flashcard .hint{font-size:13px;color:var(--text-muted);margin-top:12px}@media(max-width:600px){.navbar{padding:6px 8px}.navbar a,.navbar button.nav-link{padding:6px 8px;font-size:13px}.message{max-width:92%}.admin-page{padding:12px}.modal{max-height:95vh}}