*{margin:0;padding:0;box-sizing:border-box}body{font-family:Segoe UI,Tahoma,Geneva,Verdana,sans-serif;background:linear-gradient(135deg,#667eea,#764ba2);min-height:100vh;display:flex;justify-content:center;align-items:center;padding:20px}.container{width:100%;max-width:900px;background:#fff;border-radius:20px;box-shadow:0 20px 60px #0000004d;overflow:hidden}header{background:linear-gradient(135deg,#667eea,#764ba2);color:#fff;padding:20px 30px;display:flex;justify-content:space-between;align-items:center}header h1{font-size:24px;font-weight:600}.user-info{display:flex;align-items:center;gap:15px}.screen{padding:30px;min-height:500px}.login-box{max-width:400px;margin:50px auto;text-align:center}.login-box h2{color:#333;margin-bottom:30px}#loginForm{display:flex;flex-direction:column;gap:15px}#loginForm input{padding:12px 20px;border:2px solid #e0e0e0;border-radius:10px;font-size:16px;transition:border-color .3s}#loginForm input:focus{outline:none;border-color:#667eea}.hint{color:#666;font-size:14px;margin-top:15px}.login-hint{margin-top:20px;padding:15px;background:#f8f9fa;border-radius:10px;border-left:4px solid #667eea}.login-hint .hint{margin:5px 0;font-size:13px}.login-hint .hint:first-child{font-weight:600;color:#333;margin-bottom:8px}.menu-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(200px,1fr));gap:20px;margin-top:30px}.menu-item{background:#fff;border:2px solid #e0e0e0;border-radius:15px;padding:30px 20px;cursor:pointer;transition:all .3s;text-align:center}.menu-item:hover{border-color:#667eea;transform:translateY(-5px);box-shadow:0 10px 30px #667eea33}.menu-icon{font-size:48px;margin-bottom:15px}.menu-title{font-size:20px;font-weight:600;color:#333;margin-bottom:10px}.menu-desc{font-size:14px;color:#666}.progress-bar{background:#e0e0e0;height:30px;border-radius:15px;position:relative;margin-bottom:30px;overflow:hidden}.progress-fill{background:linear-gradient(135deg,#667eea,#764ba2);height:100%;width:0%;border-radius:15px;transition:width .5s}.progress-text{position:absolute;top:50%;left:50%;transform:translate(-50%,-50%);color:#fff;font-weight:600;text-shadow:0 1px 2px rgba(0,0,0,.2)}.question-card{background:#fff;border:2px solid #e0e0e0;border-radius:15px;padding:30px;margin-bottom:20px}.question-header{display:flex;justify-content:space-between;margin-bottom:20px}.topic-label{background:#f0f0f0;padding:5px 15px;border-radius:20px;font-size:14px;color:#666}.difficulty{padding:5px 15px;border-radius:20px;font-size:14px;font-weight:600}.difficulty.easy{background:#c3f0c3;color:#2e7d2e}.difficulty.medium{background:#fff3cd;color:#856404}.difficulty.hard{background:#f8d7da;color:#721c24}.question-text{font-size:20px;color:#333;margin-bottom:30px;line-height:1.6}.options{display:flex;flex-direction:column;gap:12px;margin-bottom:20px}.option{padding:15px 20px;border:2px solid #e0e0e0;border-radius:10px;cursor:pointer;transition:all .3s;font-size:16px}.option:hover{border-color:#667eea;background:#f8f9ff}.option.selected{border-color:#667eea;background:#f0f3ff}.option.correct{border-color:#28a745;background:#d4edda}.option.incorrect{border-color:#dc3545;background:#f8d7da}textarea,#answerTextarea{width:100%;max-width:100%;padding:15px;border:2px solid #e0e0e0;border-radius:10px;font-size:16px;font-family:inherit;resize:vertical;transition:border-color .3s;box-sizing:border-box}textarea:focus,#answerTextarea:focus{outline:none;border-color:#667eea}.true-false-options{display:flex;gap:20px;justify-content:center;margin:30px 0}.btn{padding:12px 25px;border:none;border-radius:10px;font-size:16px;font-weight:600;cursor:pointer;transition:all .3s}.btn-primary:hover{transform:translateY(-2px);box-shadow:0 5px 15px #667eea4d}.btn-secondary{background:#f0f0f0;color:#666}.btn-secondary:hover{background:#e0e0e0}.btn-large{padding:15px 40px;font-size:18px}.btn-small{padding:8px 15px;font-size:14px}.question-actions{display:flex;gap:15px;justify-content:center;margin-top:20px}.feedback{margin-top:20px;padding:20px;border-radius:10px;background:#f8f9fa;border-left:4px solid #667eea}.feedback.correct{background:#d4edda;border-left-color:#28a745}.feedback.incorrect{background:#f8d7da;border-left-color:#dc3545}.feedback-content{color:#333;line-height:1.6}.stats-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(150px,1fr));gap:20px;margin:30px 0}.stat-card{background:#f8f9fa;padding:20px;border-radius:10px;text-align:center}.stat-value{font-size:32px;font-weight:700;color:#667eea}.stat-label{font-size:14px;color:#666;margin-top:5px}.topics-list{display:flex;flex-direction:column;gap:15px;margin:20px 0}.topic-item{padding:20px;background:#f8f9fa;border-radius:10px;border-left:4px solid #667eea}.topic-title{font-size:18px;font-weight:600;color:#333;margin-bottom:10px}.topic-info{display:flex;gap:20px;color:#666;font-size:14px}.history-list{display:flex;flex-direction:column;gap:15px;margin:20px 0}.history-item{padding:15px;background:#f8f9fa;border-radius:10px;border-left:4px solid #e0e0e0}.history-item.correct{border-left-color:#28a745}.history-item.incorrect{border-left-color:#dc3545}.history-question{font-weight:600;color:#333;margin-bottom:10px}.history-answer{color:#666;margin-bottom:5px}.history-meta{display:flex;gap:15px;font-size:12px;color:#999}.loading{text-align:center;padding:40px;color:#666}.loading:after{content:"...";animation:dots 1.5s steps(4,end) infinite}@keyframes dots{0%,20%{content:"."}40%{content:".."}60%,to{content:"..."}}.ai-loading{display:flex;align-items:center;justify-content:center;padding:20px;background:#f8f9ff;border:2px solid #667eea;border-radius:10px;margin:20px 0;color:#667eea;font-weight:600}.ai-loading .spinner{width:20px;height:20px;border:2px solid #e0e0e0;border-top:2px solid #667eea;border-radius:50%;animation:spin 1s linear infinite;margin-right:10px}@keyframes spin{0%{transform:rotate(0)}to{transform:rotate(360deg)}}.ai-loading-text{animation:loadingText 2s ease-in-out infinite}@keyframes loadingText{0%,to{opacity:1}50%{opacity:.5}}.btn.loading{position:relative;color:transparent;pointer-events:none}.btn.loading:after{content:"";position:absolute;top:50%;left:50%;width:16px;height:16px;margin:-8px 0 0 -8px;border:2px solid #ffffff;border-top:2px solid transparent;border-radius:50%;animation:spin 1s linear infinite}.notification-container{position:fixed;top:20px;right:20px;z-index:1000;max-width:400px}.notification{background:#fff;border-radius:12px;box-shadow:0 10px 40px #0000001a;margin-bottom:10px;padding:16px 20px;border-left:4px solid #667eea;display:flex;align-items:flex-start;gap:12px;transform:translate(100%);animation:slideIn .3s ease-out forwards}.notification.success{border-left-color:#28a745}.notification.error{border-left-color:#dc3545}.notification.warning{border-left-color:#ffc107}.notification.info{border-left-color:#17a2b8}.notification-icon{font-size:20px;flex-shrink:0;margin-top:2px}.notification-content{flex:1}.notification-title{font-weight:600;color:#333;margin-bottom:4px;font-size:14px}.notification-message{color:#666;font-size:13px;line-height:1.4}.notification-close{background:none;border:none;color:#999;cursor:pointer;font-size:18px;padding:0;margin-left:8px;flex-shrink:0}.notification-close:hover{color:#666}.notification.closing{animation:slideOut .3s ease-in forwards}@keyframes slideIn{0%{transform:translate(100%);opacity:0}to{transform:translate(0);opacity:1}}@keyframes slideOut{0%{transform:translate(0);opacity:1}to{transform:translate(100%);opacity:0}}.hint-modal{position:fixed;top:0;left:0;right:0;bottom:0;background:#00000080;z-index:1001;display:flex;align-items:center;justify-content:center;padding:20px;opacity:0;visibility:hidden;transition:all .3s ease}.hint-modal.show{opacity:1;visibility:visible}.hint-modal-content{background:#fff;border-radius:15px;padding:30px;max-width:500px;width:100%;box-shadow:0 20px 60px #0000004d;transform:scale(.8);transition:transform .3s ease}.hint-modal.show .hint-modal-content{transform:scale(1)}.hint-modal-header{display:flex;align-items:center;margin-bottom:20px}.hint-modal-icon{font-size:24px;margin-right:10px;color:#667eea}.hint-modal-title{font-size:20px;font-weight:600;color:#333;margin:0}.hint-modal-message{color:#666;line-height:1.6;margin-bottom:25px;font-size:16px}.hint-modal-footer{text-align:right}.hint-modal-close{background:linear-gradient(135deg,#667eea,#764ba2);color:#fff;border:none;padding:12px 25px;border-radius:8px;font-weight:600;cursor:pointer;transition:transform .2s}.hint-modal-close:hover{transform:translateY(-2px)}.hint-display{background:linear-gradient(135deg,#fef3c7,#fde68a);border:2px solid #f59e0b;border-radius:12px;padding:16px;margin-bottom:20px;box-shadow:0 4px 6px #f59e0b1a;animation:slideDown .3s ease-out}@keyframes slideDown{0%{opacity:0;transform:translateY(-10px)}to{opacity:1;transform:translateY(0)}}.hint-display-header{display:flex;align-items:center;justify-content:space-between;margin-bottom:12px;padding-bottom:8px;border-bottom:1px solid rgba(245,158,11,.3)}.hint-icon{font-size:20px;margin-right:8px}.hint-title{font-size:16px;font-weight:600;color:#92400e;flex-grow:1}.hint-close-btn{background:none;border:none;font-size:24px;color:#92400e;cursor:pointer;width:28px;height:28px;display:flex;align-items:center;justify-content:center;border-radius:4px;transition:background .2s;padding:0;line-height:1}.hint-close-btn:hover{background:#f59e0b33}.hint-display-content{color:#78350f;line-height:1.6;font-size:15px;white-space:pre-wrap}.admin-panel{padding:20px}.admin-tabs{display:flex;gap:10px;margin-bottom:20px;border-bottom:2px solid #e0e0e0}.tab-btn{padding:12px 24px;background:none;border:none;border-bottom:3px solid transparent;cursor:pointer;font-weight:600;color:#666;transition:all .3s}.tab-btn.active{color:#667eea;border-bottom-color:#667eea}.tab-btn:hover{color:#667eea}.users-table{overflow-x:auto;margin:20px 0}.users-table table{width:100%;border-collapse:collapse;background:#fff;border-radius:10px;overflow:hidden}.users-table th,.users-table td{padding:12px 15px;text-align:left;border-bottom:1px solid #e0e0e0}.users-table th{background:#f8f9fa;font-weight:600;color:#333}.users-table tr:hover{background:#f8f9ff}.accuracy.good{color:#28a745;font-weight:600}.accuracy.medium{color:#ffc107;font-weight:600}.accuracy.low{color:#dc3545;font-weight:600}.user-details-modal{position:fixed;top:0;left:0;right:0;bottom:0;background:#00000080;display:flex;align-items:center;justify-content:center;padding:20px;z-index:1000}.user-details-modal .modal-content{background:#fff;border-radius:15px;max-width:900px;width:100%;max-height:90vh;overflow-y:auto;box-shadow:0 20px 60px #0000004d}.user-details-modal .modal-header{display:flex;justify-content:space-between;align-items:center;padding:20px 30px;border-bottom:2px solid #e0e0e0}.user-details-modal .modal-header h3{margin:0;color:#333}.user-details-modal .close-btn{background:none;border:none;font-size:32px;color:#999;cursor:pointer;padding:0;width:32px;height:32px;line-height:1}.user-details-modal .close-btn:hover{color:#333}.user-details-modal .modal-body{padding:30px}.user-details-modal .modal-body h4{margin-top:30px;margin-bottom:15px;color:#333}.user-details-modal .modal-body h4:first-child{margin-top:0}.activity-chart{margin-top:20px}.activity-day{padding:15px;background:#f8f9fa;border-radius:8px;margin-bottom:10px}.activity-date{font-weight:600;color:#333;margin-bottom:8px}.activity-bars{display:flex;gap:20px}.activity-bar{flex:1;padding:8px 12px;background:#fff;border-radius:5px;border-left:3px solid #667eea}.menu-item.admin-item{border-color:#ffc107;background:linear-gradient(135deg,#fff8e1,#ffecb3)}.menu-item.admin-item:hover{border-color:#ff9800;transform:translateY(-5px);box-shadow:0 10px 30px #ff980033}.recent-answers{max-height:400px;overflow-y:auto}.material-modal{position:fixed;top:0;left:0;right:0;bottom:0;background:#000000b3;display:flex;align-items:center;justify-content:center;padding:20px;z-index:1002}.material-modal-content{background:#fff;border-radius:15px;max-width:1000px;width:100%;max-height:90vh;overflow-y:auto;box-shadow:0 20px 60px #0000004d}.material-modal-header{display:flex;justify-content:space-between;align-items:center;padding:20px 30px;border-bottom:2px solid #e0e0e0;position:sticky;top:0;background:#fff;z-index:1}.material-modal-header h3{margin:0;color:#333}.material-modal-body{padding:30px}.material-info{margin-bottom:20px}.material-title{font-size:20px;font-weight:600;color:#333;margin-bottom:10px}.material-description{color:#666;font-size:14px;margin-bottom:10px;line-height:1.5}.material-page{color:#999;font-size:13px}.material-image-container{background:#f8f9fa;border-radius:10px;padding:20px;text-align:center;margin:20px 0}.material-image{max-width:100%;height:auto;border-radius:8px;box-shadow:0 4px 12px #0000001a}.material-navigation{display:flex;justify-content:space-between;align-items:center;margin-top:20px;padding:15px;background:#f8f9fa;border-radius:10px}.material-counter{font-weight:600;color:#667eea}.material-relevance{text-align:center;margin-top:10px;font-size:14px;color:#ffc107}.material-loading,.material-empty{text-align:center;padding:40px;color:#666}.material-empty p{margin:0}.autosave-indicator{font-size:12px;color:#28a745;margin-top:8px;display:flex;align-items:center;gap:5px;opacity:.8}.answer-supplement{margin-top:20px;padding:20px;background:#fff8e1;border-radius:10px;border-left:4px solid #ffc107}.answer-supplement-title{font-weight:600;color:#333;margin-bottom:10px;display:flex;align-items:center;gap:8px}.answer-supplement textarea{width:100%;margin:10px 0}.answer-supplement-actions{display:flex;gap:10px;margin-top:10px}.admin-header{display:flex;justify-content:space-between;align-items:center;margin-bottom:20px;padding-bottom:15px;border-bottom:2px solid #e0e0e0}.admin-header h2{margin:0;color:#333}.admin-content{margin-top:20px}.section-header{margin-bottom:25px}.section-header h3{color:#333;margin-bottom:5px}.section-header p{color:#666;font-size:14px;margin:0}.filters{display:flex;gap:20px;margin-bottom:20px;padding:15px;background:#f8f9fa;border-radius:10px}.filter-group{display:flex;align-items:center;gap:10px}.filter-group label{font-weight:600;color:#333}.filter-group select{padding:8px 12px;border:2px solid #e0e0e0;border-radius:8px;font-size:14px}.materials-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(250px,1fr));gap:20px;margin:20px 0}.material-card{background:#fff;border:2px solid #e0e0e0;border-radius:10px;padding:15px;cursor:pointer;transition:all .3s}.material-card:hover{border-color:#667eea;transform:translateY(-3px);box-shadow:0 5px 15px #667eea33}.material-thumbnail{width:100%;height:150px;background:#f0f0f0;border-radius:8px;overflow:hidden;margin-bottom:10px}.material-thumbnail img{width:100%;height:100%;object-fit:cover}.material-info{text-align:center}.material-stats{display:flex;justify-content:space-around;margin-top:10px;font-size:12px;color:#666}.questions-list table,.users-table table{width:100%;border-collapse:collapse;background:#fff;border-radius:10px;overflow:hidden}.questions-list th,.questions-list td{padding:12px;text-align:left;border-bottom:1px solid #e0e0e0;font-size:14px}.questions-list th{background:#f8f9fa;font-weight:600;color:#333}.questions-list tr:hover{background:#f8f9ff}.question-text-cell{max-width:400px}.detail-section{margin:25px 0;padding:20px;background:#f8f9fa;border-radius:10px}.detail-section h4,.detail-section h5{color:#333;margin-top:0;margin-bottom:15px}.detail-section p{margin:8px 0;color:#333}.edit-form .form-group,.add-form .form-group{margin-bottom:15px}.edit-form label,.add-form label{display:block;font-weight:600;color:#333;margin-bottom:5px}.edit-form input,.edit-form textarea,.add-form input,.add-form textarea,.add-form select{width:100%;padding:10px;border:2px solid #e0e0e0;border-radius:8px;font-size:14px;font-family:inherit}.edit-form input:focus,.edit-form textarea:focus,.add-form input:focus,.add-form textarea:focus,.add-form select:focus{outline:none;border-color:#667eea}.add-form{background:#fff8e1;padding:20px;border-radius:10px;margin-bottom:20px;border-left:4px solid #ffc107}.add-form h4{margin-top:0;color:#333}.knowledge-list{display:flex;flex-direction:column;gap:15px}.knowledge-item{background:#fff;padding:15px;border-radius:10px;border-left:4px solid #667eea}.knowledge-header{display:flex;justify-content:space-between;align-items:center;margin-bottom:10px}.knowledge-fact{font-size:15px;color:#333;line-height:1.6;margin:10px 0}.knowledge-context{font-size:13px;color:#666;margin-top:8px;font-style:italic}.knowledge-stats{display:flex;gap:15px;margin-top:10px;font-size:12px;color:#999}.importance{display:inline-block;padding:4px 10px;border-radius:12px;font-size:12px;font-weight:600}.importance-1,.importance-2{background:#e0e0e0;color:#666}.importance-3{background:#fff3cd;color:#856404}.importance-4,.importance-5{background:#f8d7da;color:#721c24}.material-item,.question-item{display:flex;align-items:center;gap:15px;padding:12px;background:#fff;border:1px solid #e0e0e0;border-radius:8px;margin-bottom:10px}.material-item img{flex-shrink:0}.sample-answer{padding:12px;background:#fff;border:1px solid #e0e0e0;border-radius:8px;margin-bottom:10px}.modal-content.large{max-width:1200px;max-height:90vh;overflow-y:auto}.question-details-modal,.material-details-modal,.topic-details-modal{position:fixed;top:0;left:0;right:0;bottom:0;background:#00000080;display:flex;align-items:flex-start;justify-content:center;padding:40px 20px 20px;z-index:1000;overflow-y:auto}.question-details-modal .modal-content,.material-details-modal .modal-content,.topic-details-modal .modal-content{margin:0 auto;max-height:85vh;display:flex;flex-direction:column;position:relative}.question-details-modal .modal-header,.material-details-modal .modal-header,.topic-details-modal .modal-header{position:sticky;top:0;background:#fff;z-index:10;flex-shrink:0}.question-details-modal .modal-body,.material-details-modal .modal-body,.topic-details-modal .modal-body{overflow-y:auto;flex:1}.admin-students .section-header{display:flex;justify-content:space-between;align-items:flex-start}.material-preview-modal{position:fixed;top:0;left:0;right:0;bottom:0;background:#000000d9;display:flex;align-items:center;justify-content:center;padding:20px;z-index:2000;animation:fadeIn .2s ease-in}.material-preview-content{background:#fff;border-radius:15px;max-width:1000px;max-height:90vh;width:100%;display:flex;flex-direction:column;box-shadow:0 20px 60px #00000080;animation:slideUp .3s ease-out}.material-preview-header{display:flex;justify-content:space-between;align-items:flex-start;padding:20px 30px;border-bottom:2px solid #e0e0e0;background:#fff;border-radius:15px 15px 0 0}.material-preview-header h3{margin:0;color:#333}.material-preview-body{padding:30px;overflow-y:auto;flex:1}@keyframes slideUp{0%{transform:translateY(50px);opacity:0}to{transform:translateY(0);opacity:1}}@media(max-width:768px){.container{border-radius:0;min-height:100vh}.menu-grid{grid-template-columns:1fr}.true-false-options,.question-actions{flex-direction:column}.notification-container{top:10px;right:10px;left:10px;max-width:none}.notification{margin-bottom:8px;padding:12px 16px}.hint-modal{padding:10px}.hint-modal-content{padding:20px}.users-table{font-size:14px}.admin-tabs{overflow-x:auto}.user-details-modal .modal-content{max-height:95vh}.activity-bars{flex-direction:column;gap:10px}}.change-password-container{max-width:500px;margin:0 auto;padding:30px;background:#fff;border-radius:12px;box-shadow:0 2px 8px #0000001a}.change-password-container h2{margin-top:0;margin-bottom:25px;color:#2c3e50;font-size:24px;text-align:center}.change-password-form{display:flex;flex-direction:column;gap:20px}.change-password-form .form-group{display:flex;flex-direction:column;gap:8px}.change-password-form label{font-weight:600;color:#34495e;font-size:14px}.change-password-form input[type=password]{padding:12px;border:2px solid #e0e0e0;border-radius:8px;font-size:16px;transition:border-color .3s}.change-password-form input[type=password]:focus{outline:none;border-color:#3498db}.change-password-form input[type=password]:disabled{background-color:#f5f5f5;cursor:not-allowed}.change-password-form small{color:#7f8c8d;font-size:12px;margin-top:-4px}.form-actions{display:flex;gap:12px;margin-top:10px}.btn-primary,.btn-secondary{padding:12px 24px;border:none;border-radius:8px;font-size:16px;font-weight:600;cursor:pointer;transition:all .3s;flex:1}.btn-primary{background:linear-gradient(135deg,#667eea,#764ba2);color:#fff}.btn-primary:hover:not(:disabled){transform:translateY(-2px);box-shadow:0 4px 12px #667eea66}.btn-primary:disabled{background:#bdc3c7;cursor:not-allowed;transform:none}.btn-secondary{background:#fff;color:#34495e;border:2px solid #e0e0e0}.btn-secondary:hover:not(:disabled){background:#f8f9fa;border-color:#bdc3c7}.btn-secondary:disabled{opacity:.5;cursor:not-allowed}.error-message{background-color:#fee;color:#c33;padding:12px 16px;border-radius:8px;border-left:4px solid #e74c3c;font-size:14px;animation:slideDown .3s ease-out}.success-message{background-color:#d4edda;color:#155724;padding:12px 16px;border-radius:8px;border-left:4px solid #28a745;font-size:14px;animation:slideDown .3s ease-out}.register-user-modal{position:fixed;top:0;left:0;right:0;bottom:0;background:#00000080;display:flex;align-items:center;justify-content:center;z-index:1000;animation:fadeIn .3s ease-out}.register-user-modal .modal-content{background:#fff;border-radius:12px;padding:30px;max-width:600px;width:90%;max-height:90vh;overflow-y:auto;box-shadow:0 10px 40px #0003;animation:slideUp .3s ease-out}.register-user-modal h2{margin-top:0;margin-bottom:25px;color:#2c3e50;font-size:24px;text-align:center}.register-user-form{display:flex;flex-direction:column;gap:20px}.register-user-form .form-group{display:flex;flex-direction:column;gap:8px}.register-user-form label{font-weight:600;color:#34495e;font-size:14px}.register-user-form input,.register-user-form select{padding:12px;border:2px solid #e0e0e0;border-radius:8px;font-size:16px;transition:border-color .3s}.register-user-form input:focus,.register-user-form select:focus{outline:none;border-color:#3498db}.register-user-form input:disabled,.register-user-form select:disabled{background-color:#f5f5f5;cursor:not-allowed}.register-user-form small{color:#7f8c8d;font-size:12px;margin-top:-4px}@keyframes fadeIn{0%{opacity:0}to{opacity:1}}@keyframes slideUp{0%{opacity:0;transform:translateY(20px)}to{opacity:1;transform:translateY(0)}}
