:root{--primary: #4b5563;--primary-hover: #374151;--primary-active: #1f2937;--primary-light: #6b7280;--primary-dark: #374151;--secondary: #6b7280;--secondary-hover: #4b5563;--secondary-active: #374151;--secondary-light: #9ca3af;--bg-primary: #F5F5F5;--bg-secondary: #FFFFFF;--bg-elevated: #ECECEC;--bg-tertiary: #E0E0E0;--bg-hover: #F0F0F0;--bg-overlay: rgba(255, 255, 255, .9);--text-primary: #111827;--text-secondary: #4b5563;--text-tertiary: #5A6B7D;--text-muted: #888888;--text-placeholder: #B0B0B0;--success: #10B981;--success-light: #D1F4E6;--danger: #EF4444;--danger-light: #FED7D7;--warning: #F59E0B;--warning-light: #FEF3C7;--info: #3b82f6;--info-light: #DFFBFF;--border: #D0D0D0;--border-light: #E0E0E0;--border-darker: #C0C0C0;--radius-xs: .25rem;--radius-sm: .375rem;--radius: .5rem;--radius-md: .625rem;--radius-lg: .75rem;--radius-xl: 1rem;--radius-full: 9999px;--shadow-xs: 0 1px 2px 0 rgba(0, 0, 0, .05);--shadow-sm: 0 1px 3px 0 rgba(0, 0, 0, .08), 0 1px 2px 0 rgba(0, 0, 0, .04);--shadow: 0 4px 6px -1px rgba(0, 0, 0, .1), 0 2px 4px -2px rgba(0, 0, 0, .08);--shadow-md: 0 10px 15px -3px rgba(0, 0, 0, .1), 0 4px 6px -4px rgba(0, 0, 0, .08);--shadow-lg: 0 20px 25px -5px rgba(0, 0, 0, .1), 0 8px 10px -6px rgba(0, 0, 0, .08);--shadow-xl: 0 25px 50px -12px rgba(0, 0, 0, .15);--gradient-primary: linear-gradient(135deg, var(--primary), var(--secondary));--gradient-accent: linear-gradient(135deg, var(--secondary), var(--info));--gradient-glow: linear-gradient(135deg, var(--primary), var(--info));--transition-fast: .15s ease-in-out;--transition-normal: .2s ease-in-out;--transition-slow: .3s ease-in-out;--font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Roboto", "Oxygen", "Ubuntu", "Cantarell", "Fira Sans", "Droid Sans", "Helvetica Neue", sans-serif;--font-mono: "Monaco", "Menlo", "Ubuntu Mono", "Cascadia Code", "Source Code Pro", monospace;--text-xs: .75rem;--text-sm: .875rem;--text-base: 1rem;--text-lg: 1.125rem;--text-xl: 1.25rem;--text-2xl: 1.5rem;--text-3xl: 1.875rem;--text-4xl: 2.25rem;--text-5xl: 3rem;--line-height-xs: 1;--line-height-sm: 1.25;--line-height-base: 1.5;--line-height-lg: 1.75;--line-height-xl: 2;--letter-spacing-tighter: -.05em;--letter-spacing-tight: -.025em;--letter-spacing-normal: 0em;--letter-spacing-wide: .025em;--letter-spacing-wider: .05em;--space-0: 0px;--space-xs: .25rem;--space-sm: .5rem;--space-md: 1rem;--space-lg: 1.5rem;--space-xl: 2rem;--space-2xl: 3rem;--space-3xl: 4rem;--space-4xl: 6rem;font-family:var(--font-family);line-height:var(--line-height-base);font-weight:400;color-scheme:dark}*{box-sizing:border-box;margin:0;padding:0}html{scroll-behavior:smooth}body{background-color:var(--bg-primary);color:var(--text-primary);min-height:100vh;-webkit-font-smoothing:antialiased;-moz-osx-font-smoothing:grayscale;background-image:radial-gradient(at 20% 50%,rgba(75,85,99,.04) 0px,transparent 50%),radial-gradient(at 80% 80%,rgba(107,114,128,.04) 0px,transparent 50%);background-attachment:fixed}#root{min-height:100vh}h1,h2,h3,h4,h5,h6{line-height:var(--line-height-sm);font-weight:600;letter-spacing:var(--letter-spacing-tight)}h1{font-size:var(--text-4xl);font-weight:700}h2{font-size:var(--text-3xl);font-weight:700}h3{font-size:var(--text-2xl);font-weight:600}h4{font-size:var(--text-xl);font-weight:600}h5{font-size:var(--text-lg);font-weight:600}h6{font-size:var(--text-base);font-weight:600}p{margin-bottom:var(--space-md);color:var(--text-secondary)}small{font-size:var(--text-sm);color:var(--text-tertiary)}code{font-family:var(--font-mono);background-color:#f5f5f5;color:#c6097e;padding:.125rem .375rem;border-radius:var(--radius-sm);font-size:.9em}pre{background-color:#f5f5f5;border:1px solid var(--border);border-radius:var(--radius-lg);padding:var(--space-lg);overflow-x:auto;margin-bottom:var(--space-md);font-family:var(--font-mono);font-size:var(--text-sm);line-height:var(--line-height-base)}pre code{background:none;color:#c6097e;padding:0;border-radius:0}a{color:var(--primary);text-decoration:none;transition:color var(--transition-fast)}a:hover{color:var(--primary-light);text-decoration:underline}input,textarea,select{font-family:inherit;font-size:var(--text-base);background-color:#fafafa;border:1px solid var(--border);color:var(--text-primary);padding:var(--space-sm) var(--space-md);border-radius:var(--radius-md);outline:none;transition:all var(--transition-normal)}input::placeholder,textarea::placeholder,select::placeholder{color:var(--text-placeholder)}input:hover,textarea:hover,select:hover{border-color:#b0b0b0;background-color:#fff}input:focus,textarea:focus,select:focus{border-color:var(--primary);background-color:#fff;box-shadow:0 0 0 3px #4b55631f}textarea{resize:vertical;min-height:100px}button{cursor:pointer;border:none;background:transparent;color:inherit;font-family:inherit;display:inline-flex;align-items:center;justify-content:center;gap:var(--space-sm);transition:all var(--transition-normal);font-weight:500;border-radius:var(--radius-md);font-size:var(--text-base)}button:disabled{opacity:.5;cursor:not-allowed}.btn{padding:var(--space-sm) var(--space-md);font-size:var(--text-sm);font-weight:500;border-radius:var(--radius-md);transition:all var(--transition-normal)}.btn-primary{background:var(--gradient-primary);color:#fff;box-shadow:var(--shadow-sm)}.btn-primary:hover:not(:disabled){background:linear-gradient(135deg,var(--primary-hover),var(--primary-active));box-shadow:var(--shadow-md);transform:translateY(-1px)}.btn-primary:active:not(:disabled){transform:translateY(0);box-shadow:var(--shadow-sm)}.btn-secondary{background-color:var(--bg-secondary);color:var(--text-primary);border:1px solid var(--border)}.btn-secondary:hover:not(:disabled){background-color:#f0f0f0;border-color:#b0b0b0;box-shadow:var(--shadow-sm)}.btn-danger{background-color:#ef444426;color:var(--danger-light);border:1px solid rgba(239,68,68,.3)}.btn-danger:hover:not(:disabled){background-color:#ef444440;border-color:#ef444480;box-shadow:0 0 0 3px #ef44441a}.btn-tertiary{background-color:transparent;color:var(--primary);border:1px solid var(--border)}.btn-tertiary:hover:not(:disabled){background-color:var(--primary);color:#fff;border-color:var(--primary)}.btn-ghost{background-color:transparent;color:var(--text-secondary);border:none}.btn-ghost:hover:not(:disabled){background-color:var(--bg-secondary);color:var(--text-primary)}.btn-sm{padding:var(--space-xs) var(--space-sm);font-size:var(--text-xs);border-radius:var(--radius-sm)}.btn-lg{padding:var(--space-md) var(--space-lg);font-size:var(--text-lg);border-radius:var(--radius-lg)}.btn-icon{width:2.5rem;height:2.5rem;padding:0;border-radius:var(--radius-lg)}.btn-loading{pointer-events:none;opacity:.8}.auth-container{display:flex;flex-direction:row;align-items:center;justify-content:center;min-height:100vh;padding:var(--space-lg);background:radial-gradient(circle at top right,rgba(75,85,99,.06),transparent 40%),radial-gradient(circle at bottom left,rgba(107,114,128,.04),transparent 40%)}.card{background-color:#fff;border:1px solid var(--border);border-radius:var(--radius-lg);padding:var(--space-xl);box-shadow:var(--shadow-lg);width:100%;max-width:450px;transition:all var(--transition-normal)}.card:hover{border-color:#b0b0b0;box-shadow:var(--shadow-xl)}.card-compact{padding:var(--space-lg)}.card-elevated{background:linear-gradient(135deg,#4b55630a,#6b72800a)}.heading{font-size:var(--text-3xl);font-weight:700;margin-bottom:var(--space-lg);text-align:center;background:var(--gradient-glow);-webkit-background-clip:text;-webkit-text-fill-color:transparent;background-clip:text}.form-group{margin-bottom:var(--space-md)}.label{display:block;font-size:var(--text-sm);color:var(--text-secondary);margin-bottom:var(--space-xs);font-weight:500;text-transform:uppercase;letter-spacing:var(--letter-spacing-wide)}.app-layout{display:grid;grid-template-columns:260px 1fr;height:100vh;overflow:hidden;gap:0}.app-layout-3col{display:grid;grid-template-columns:260px 300px 1fr;height:100vh;overflow:hidden}.sidebar{background-color:var(--bg-primary);border-right:1px solid var(--border);display:flex;flex-direction:column;height:100%}.sidebar-header{padding:var(--space-md);border-bottom:1px solid var(--border);font-weight:600;font-size:var(--text-lg);display:flex;align-items:center;gap:var(--space-sm)}.sidebar-content{flex:1;overflow-y:auto;padding:var(--space-sm)}.sidebar-footer{padding:var(--space-md);border-top:1px solid var(--border)}.nav-item{padding:var(--space-sm) var(--space-md);border-radius:var(--radius-md);margin-bottom:var(--space-xs);cursor:pointer;color:var(--text-tertiary);display:flex;align-items:center;gap:var(--space-sm);font-size:var(--text-sm);transition:all var(--transition-normal);white-space:nowrap;overflow:hidden;text-overflow:ellipsis}.nav-item:hover{background-color:var(--bg-secondary);color:var(--text-primary);padding-left:calc(var(--space-md) + 4px)}.nav-item.active{background-color:#e8f0f8;color:var(--primary);font-weight:500;left:2px;border-left:3px solid var(--primary);padding-left:calc(var(--space-md) - 3px)}.main-content{background-color:var(--bg-primary);display:flex;flex-direction:column;overflow:hidden}.content-header{padding:var(--space-lg);border-bottom:1px solid var(--border);background:linear-gradient(135deg,var(--bg-primary),var(--bg-secondary))}.content-header h1{margin:0;margin-bottom:var(--space-sm)}.content-header p{margin:0;font-size:var(--text-sm)}.content-body{flex:1;overflow-y:auto;padding:var(--space-lg)}.chat-area{background-color:var(--bg-primary);display:flex;flex-direction:column;position:relative;overflow:hidden;flex:1}.messages{flex:1;overflow-y:auto;padding:var(--space-xl) var(--space-lg);padding-bottom:150px;display:flex;flex-direction:column;gap:var(--space-md)}.input-area{position:absolute;bottom:0;left:0;right:0;padding:var(--space-xl) var(--space-lg);background:linear-gradient(180deg,transparent,var(--bg-primary) 30%);-webkit-backdrop-filter:blur(10px);backdrop-filter:blur(10px);border-top:1px solid var(--border)}.message{display:flex;gap:var(--space-md);max-width:100%;animation:fadeIn var(--transition-normal)}.message.user{justify-content:flex-end;flex-direction:row-reverse}.message.assistant{justify-content:flex-start}.message-content{background-color:var(--bg-secondary);border:1px solid var(--border);border-radius:var(--radius-lg);padding:var(--space-md);word-wrap:break-word;max-width:min(50vw,600px);line-height:var(--line-height-lg)}.message.user .message-content{background:var(--gradient-primary);border:none;color:#fff}.message.assistant .message-content{background-color:#f5f5f5;color:var(--text-primary);border:1px solid var(--border)}.avatar{width:2.5rem;height:2.5rem;border-radius:var(--radius-xl);background:var(--gradient-primary);display:flex;align-items:center;justify-content:center;font-weight:700;font-size:var(--text-sm);color:#fff;flex-shrink:0;box-shadow:var(--shadow-sm)}.avatar.assistant{background:var(--gradient-accent)}::-webkit-scrollbar{width:8px;height:8px}::-webkit-scrollbar-track{background:var(--bg-primary)}::-webkit-scrollbar-thumb{background:#d0d0d0;border-radius:4px}::-webkit-scrollbar-thumb:hover{background:#b0b0b0}.spinner{width:1.5rem;height:1.5rem;border:3px solid var(--bg-elevated);border-top-color:var(--primary);border-radius:50%;animation:spin 1s linear infinite}@keyframes spin{to{transform:rotate(360deg)}}.streaming:after{content:"▋";animation:blink 1s infinite;color:var(--primary)}@keyframes blink{50%{opacity:.5}}.text-right{text-align:right}.text-muted{color:var(--text-muted)}.text-secondary{color:var(--text-secondary)}.text-primary{color:var(--primary)}.text-success{color:var(--success)}.text-danger{color:var(--danger)}.text-warning{color:var(--warning)}.mt-xs{margin-top:var(--space-xs)}.mt-sm{margin-top:var(--space-sm)}.mt-md{margin-top:var(--space-md)}.mt-lg{margin-top:var(--space-lg)}.mt-xl{margin-top:var(--space-xl)}.mb-xs{margin-bottom:var(--space-xs)}.mb-sm{margin-bottom:var(--space-sm)}.mb-md{margin-bottom:var(--space-md)}.mb-lg{margin-bottom:var(--space-lg)}.mb-xl{margin-bottom:var(--space-xl)}.px-xs{padding-left:var(--space-xs);padding-right:var(--space-xs)}.px-sm{padding-left:var(--space-sm);padding-right:var(--space-sm)}.px-md{padding-left:var(--space-md);padding-right:var(--space-md)}.px-lg{padding-left:var(--space-lg);padding-right:var(--space-lg)}.gap-sm{gap:var(--space-sm)}.gap-md{gap:var(--space-md)}.gap-lg{gap:var(--space-lg)}@media(max-width:1024px){.app-layout-3col{grid-template-columns:200px 250px 1fr}.message-content{max-width:min(70vw,500px)}}@media(max-width:768px){.app-layout,.app-layout-3col{grid-template-columns:1fr}.sidebar{display:none}.content-body{padding:var(--space-md)}.message-content{max-width:90vw}}.lecturer-dashboard{padding:40px 20px;max-width:1400px;margin:0 auto}.dashboard-header{margin-bottom:40px;text-align:center}.dashboard-header h1{font-size:2.5rem;color:var(--primary);margin-bottom:10px;font-weight:700}.dashboard-header p{font-size:1.1rem;color:#666}.subjects-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(320px,1fr));gap:24px;margin-bottom:40px}.subject-card{background:#fff;border:2px solid #e0e0e0;border-radius:12px;overflow:hidden;cursor:pointer;transition:all .3s ease;display:flex;flex-direction:column;height:100%;box-shadow:0 2px 8px #00000014}.subject-card:hover{border-color:var(--secondary);box-shadow:0 8px 24px #0a66ae26;transform:translateY(-4px)}.card-header{background:linear-gradient(135deg,var(--primary) 0%,var(--secondary) 100%);color:#fff;padding:24px;flex-shrink:0}.card-header h2{font-size:1.3rem;margin:0;font-weight:600}.card-stats{display:flex;padding:24px;gap:24px;flex:1}.stat{flex:1;display:flex;flex-direction:column;align-items:center;text-align:center}.stat-label{font-size:.9rem;color:#888;margin-bottom:8px;font-weight:500;text-transform:uppercase;letter-spacing:.5px}.stat-value{font-size:2.2rem;color:var(--primary);font-weight:700}.card-students{padding:16px 24px;border-top:1px solid #f0f0f0;flex:1;overflow-y:auto;max-height:200px}.card-students h4{margin:0 0 12px;font-size:.95rem;color:#333;font-weight:600;text-transform:uppercase;letter-spacing:.5px}.students-list{display:flex;flex-direction:column;gap:8px}.student-item{padding:8px 12px;background:#f5f5f5;border-radius:6px;font-size:.85rem;color:#555;border-left:3px solid var(--secondary)}.card-footer{padding:16px 24px;border-top:1px solid #f0f0f0}.view-button{width:100%;padding:12px 16px;background:linear-gradient(135deg,var(--primary) 0%,var(--secondary) 100%);color:#fff;border:none;border-radius:8px;font-size:1rem;font-weight:600;cursor:pointer;transition:all .3s ease}.view-button:hover{transform:scale(1.02);box-shadow:0 4px 12px #0a66ae4d}.view-button:active{transform:scale(.98)}.error-message{background:#fff3cd;border:1px solid #ffc107;border-radius:8px;padding:16px;margin-bottom:24px;display:flex;justify-content:space-between;align-items:center;color:#856404}.error-message button{background:#ffc107;border:none;padding:8px 16px;border-radius:6px;cursor:pointer;font-weight:600;transition:all .3s ease}.error-message button:hover{background:#ffb300}.empty-state{text-align:center;padding:60px 20px;background:#f9f9f9;border-radius:12px;color:#888}.empty-state p{font-size:1.2rem;margin:0}@media(max-width:768px){.subjects-grid{grid-template-columns:1fr}.dashboard-header h1{font-size:2rem}.stat-value{font-size:1.8rem}}.students-class-view{width:100%}.class-tabs{display:flex;gap:12px;margin-bottom:24px;flex-wrap:wrap;border-bottom:2px solid #e0e0e0;padding-bottom:12px}.class-tab{padding:12px 16px;background:#f5f5f5;border:2px solid #e0e0e0;border-bottom:none;border-radius:8px 8px 0 0;cursor:pointer;font-size:.95rem;font-weight:600;color:#666;transition:all .3s ease;display:flex;align-items:center;gap:8px}.class-tab:hover{background:#e8f1f8;border-color:var(--secondary);color:var(--secondary)}.class-tab.active{background:#fff;border-color:var(--secondary);color:var(--primary);border-bottom:2px solid var(--secondary)}.tab-name{flex:1}.tab-count{background:var(--primary);color:#fff;padding:2px 8px;border-radius:12px;font-size:.8rem;font-weight:700}.students-table{background:#fff;border:1px solid #e0e0e0;border-radius:8px;overflow:hidden;box-shadow:0 2px 4px #0000000d}.name-cell{font-weight:600}.student-name{color:var(--primary)}.engagement-bar{width:100%;height:24px;background:#f0f0f0;border-radius:4px;overflow:hidden;position:relative;display:flex;align-items:center}.engagement-fill{height:100%;background:linear-gradient(90deg,var(--info) 0%,var(--secondary) 100%);transition:width .3s ease}.engagement-text{position:absolute;width:100%;text-align:center;font-size:.8rem;font-weight:700;color:#333;z-index:1}.view-profile-btn{padding:8px 16px;background:linear-gradient(135deg,var(--primary) 0%,var(--secondary) 100%);color:#fff;border:none;border-radius:6px;cursor:pointer;font-weight:600;font-size:.9rem;transition:all .3s ease}.view-profile-btn:hover{transform:scale(1.05);box-shadow:0 4px 12px #0a66ae4d}.view-profile-btn:active{transform:scale(.95)}@media(max-width:1024px){.controls{flex-direction:column}.search-input,.sort-select{min-width:100%}table{font-size:.9rem}th,td{padding:12px 8px}}@media(max-width:768px){.class-tabs{flex-direction:column}.class-tab{justify-content:space-between;width:100%}table{font-size:.85rem}th{font-size:.8rem}th,td{padding:10px 6px}.view-profile-btn{padding:6px 12px;font-size:.8rem}.engagement-text{font-size:.7rem}}.documents-management{width:100%}.controls{display:flex;gap:16px;margin-bottom:24px;flex-wrap:wrap}.search-input{flex:1;min-width:250px;padding:12px 16px;border:2px solid #e0e0e0;border-radius:8px;font-size:1rem;transition:all .3s ease}.search-input:focus{outline:none;border-color:var(--secondary);box-shadow:0 0 0 3px #0a66ae1a}.sort-select{padding:12px 16px;border:2px solid #e0e0e0;border-radius:8px;font-size:1rem;background:#fff;cursor:pointer;transition:all .3s ease;min-width:180px}.sort-select:focus{outline:none;border-color:var(--secondary);box-shadow:0 0 0 3px #0a66ae1a}.upload-btn{padding:12px 24px;background:linear-gradient(135deg,var(--primary) 0%,var(--secondary) 100%);color:#fff;border:none;border-radius:8px;font-size:1rem;font-weight:600;cursor:pointer;transition:all .3s ease;white-space:nowrap}.upload-btn:hover{transform:translateY(-2px);box-shadow:0 4px 12px #0a66ae4d}.upload-btn:active{transform:translateY(0)}.documents-table{background:#fff;border:1px solid #e0e0e0;border-radius:8px;overflow:hidden;box-shadow:0 2px 4px #0000000d}table{width:100%;border-collapse:collapse}thead{background:#f9f9f9;border-bottom:2px solid #e0e0e0}th{padding:16px 12px;text-align:left;font-weight:700;color:#333;font-size:.9rem;text-transform:uppercase;letter-spacing:.5px}tbody tr{border-bottom:1px solid #f0f0f0;transition:background .3s ease}tbody tr:hover{background:#f5f9ff}td{padding:14px 12px;color:#333}.filename-cell{font-weight:600}.filename{color:var(--primary);word-break:break-word}.text-center{text-align:center}.text-muted{color:#888;font-size:.9rem}.access-badge{display:inline-block;background:#e8f1f8;color:var(--secondary);padding:4px 12px;border-radius:12px;font-weight:600;font-size:.9rem}.relevance-score{display:flex;align-items:center;gap:8px;justify-content:center}.relevance-bar{width:60px;height:6px;background:#f0f0f0;border-radius:3px;overflow:hidden}.relevance-fill{height:100%;background:linear-gradient(90deg,var(--info) 0%,var(--secondary) 100%)}.delete-btn{padding:6px 12px;background:#ffebee;color:#c62828;border:1px solid #ef5350;border-radius:6px;cursor:pointer;font-weight:600;font-size:.9rem;transition:all .3s ease}.delete-btn:hover{background:#ffcdd2;border-color:#e53935}.empty-message{text-align:center;color:#888;padding:40px 20px!important;font-size:1.1rem}.modal-overlay{position:fixed;inset:0;background:#00000080;display:flex;align-items:center;justify-content:center;z-index:1000;animation:fadeIn .3s ease}@keyframes fadeIn{0%{opacity:0}to{opacity:1}}.modal{background:#fff;border-radius:12px;width:90%;max-width:500px;box-shadow:0 20px 60px #0000004d;display:flex;flex-direction:column;max-height:90vh;overflow-y:auto}.modal-header{display:flex;justify-content:space-between;align-items:center;padding:20px 24px;border-bottom:1px solid #e0e0e0}.modal-header h2{font-size:1.5rem;margin:0;color:var(--primary)}.close-btn{background:none;border:none;font-size:2rem;cursor:pointer;color:#666;transition:color .3s ease;padding:0;width:40px;height:40px;display:flex;align-items:center;justify-content:center}.close-btn:hover{color:var(--primary)}.modal-content{padding:24px;flex:1}.file-input-wrapper{position:relative;margin-bottom:16px}.file-input-wrapper input[type=file]{display:none}.file-label{display:block;padding:24px;border:2px dashed var(--secondary);border-radius:8px;text-align:center;cursor:pointer;background:#f5f9ff;transition:all .3s ease;font-weight:600;color:var(--secondary)}.file-label:hover{background:#e8f1f8;border-color:var(--primary)}.file-input-wrapper 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