*{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;padding:20px}.container{max-width:1200px;margin:0 auto;background:#fffffff2;border-radius:20px;-webkit-backdrop-filter:blur(10px);backdrop-filter:blur(10px);box-shadow:0 20px 40px #0000001a;overflow:hidden}input,select{padding:10px 12px;border-radius:10px;border:1px solid #ddd;outline:none}input:focus,select:focus{border-color:#667eea;box-shadow:0 0 0 3px #667eea26}.modal-backdrop{position:fixed;top:0;left:0;right:0;bottom:0;background:#000000b3;z-index:1000;overflow-y:auto;padding:20px 0}body.modal-open{overflow:hidden}.modal{position:absolute;top:20px;left:50%;transform:translate(-50%);background:#fff;width:calc(100% - 40px);max-width:900px;max-height:calc(100vh - 40px);border-radius:16px;box-shadow:0 20px 60px #0000004d;overflow:hidden}.modal-header{display:flex;align-items:center;justify-content:space-between;padding:20px 24px;border-bottom:1px solid #e5e7eb;background:linear-gradient(135deg,#667eea,#764ba2);color:#fff}.modal-header h3{margin:0;font-size:1.25em}.close-btn{background:#fff3;color:#fff;border:none;width:32px;height:32px;border-radius:50%;cursor:pointer;display:flex;align-items:center;justify-content:center;font-size:14px;transition:background .2s}.close-btn:hover{background:#ffffff4d}.modal-body{padding:24px;max-height:calc(90vh - 80px);overflow-y:auto}.modal-section{background:#f8fafc;padding:16px;border-radius:12px;margin-bottom:16px;border:1px solid #e2e8f0}.modal-section h4{margin:0 0 12px;color:#334155;font-size:1.1em}.toggle-btn.primary{background:#3b82f6;color:#fff}.toggle-btn.primary:hover{background:#2563eb}.toggle-btn.primary:disabled{background:#9ca3af;cursor:not-allowed}.toggle-btn.small{padding:4px 8px;font-size:.8em}@media (max-width: 768px){.container{margin:10px;border-radius:15px}.modal-backdrop{padding:10px 0}.modal{top:10px;width:calc(100% - 20px);max-height:calc(100vh - 20px)}.modal-header{padding:16px 20px}.modal-body{padding:20px}}@media (max-width: 480px){.modal{border-radius:12px;top:5px;width:calc(100% - 10px);max-height:calc(100vh - 10px)}.modal-header{padding:12px 16px}.modal-body{padding:16px}}.header{background:linear-gradient(135deg,#ff6b6b,#ffd93d);padding:30px;color:#fff;position:relative;overflow:hidden}.header-content{display:flex;align-items:center;gap:12px;justify-content:space-between}.header-left{cursor:pointer}.header-right{display:flex;gap:8px;align-items:center;position:relative;z-index:10}.user-info{text-align:right}.user-name{font-weight:600}.user-role{font-size:12px;opacity:.8}.header-buttons{display:flex;gap:8px;align-items:center}.header:before{content:"📚";position:absolute;top:-20px;left:-20px;font-size:100px;opacity:.1}.header:after{content:"🎯";position:absolute;bottom:-20px;right:-20px;font-size:100px;opacity:.1}.header h1{font-size:2em;margin-bottom:6px;text-shadow:2px 2px 4px rgba(0,0,0,.3)}.logout-btn{position:relative;z-index:20}.logout-btn:hover{background:#4a5568!important}.delete-btn{background:#e53e3e!important}.delete-btn:hover{background:#c53030!important}@media (max-width: 768px){.header{padding:20px}.header-content{flex-direction:column;gap:16px;align-items:stretch}.header-left{text-align:center}.header-right{flex-direction:column;gap:12px}.user-info{text-align:center}.header-buttons{justify-content:center;flex-wrap:wrap}.header h1{font-size:1.6em}}@media (max-width: 480px){.header{padding:16px}.header h1{font-size:1.4em}.header-buttons{flex-direction:column;width:100%}.header-buttons .toggle-btn{width:100%}}.progress-overview{padding:20px 30px;background:linear-gradient(135deg,#a8edea,#fed6e3);display:grid;grid-template-columns:repeat(auto-fit,minmax(200px,1fr));gap:20px}.progress-card{background:#fff;padding:20px;border-radius:15px;text-align:center;box-shadow:0 10px 20px #0000001a}.progress-card .icon{font-size:2.2em;margin-bottom:10px}.progress-bar{background:#e0e0e0;height:8px;border-radius:4px;overflow:hidden;margin:10px 0}.progress-fill{height:100%;border-radius:4px;transition:width .3s ease}@media (max-width: 768px){.progress-overview{grid-template-columns:1fr;gap:15px;padding:20px;border-radius:15px}}.sections{min-height:300px;padding:20px 30px}.section{margin-bottom:28px;background:#fff;border-radius:15px;padding:20px;box-shadow:0 5px 15px #00000014;border-left:5px solid #667eea}.tasks-list{padding-inline:0}.section-header{display:flex;align-items:center;margin-bottom:16px;cursor:pointer;-webkit-user-select:none;user-select:none;gap:12px}.section-header .icon{font-size:1.6em}.section-header h2{color:#333;flex-grow:1}.toggle-btn,.count-week{background:#667eea;color:#fff;border:none;padding:8px 15px;border-radius:20px;cursor:pointer;transition:background .3s ease}.toggle-btn:hover{background:#5a67d8}.tasks-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(40px,1fr));gap:8px;margin-top:8px;transition:all .3s ease;overflow:visible}.section.collapsed .tasks-grid{max-height:0;margin-top:0;opacity:0;overflow:hidden}.task-item{aspect-ratio:1;border:2px solid #e0e0e0;border-radius:8px;display:flex;align-items:center;justify-content:center;font-weight:700;cursor:pointer;transition:all .3s ease;position:relative;background:#fff}.task-item.has-picker{z-index:10000}.task-item:hover{transform:scale(1.06);box-shadow:0 5px 15px #0003}.task-item.readonly:hover{transform:none;box-shadow:none}.task-item.completed{background:linear-gradient(135deg,#4caf50,#45a049);color:#fff;border-color:#4caf50}.task-item.overdue{background:linear-gradient(135deg,#ff4d4f,#d9363e);color:#fff;border-color:#ff4d4f}.task-item.mistakes{background:linear-gradient(135deg,#ffa940,#fa8c16);color:#fff;border-color:#fa8c16}.status-picker{position:absolute;top:100%;left:50%;transform:translate(-50%);background:#fff;border:1px solid #e0e0e0;border-radius:8px;box-shadow:0 10px 24px #0003;display:flex;flex-direction:column;gap:6px;padding:8px;z-index:9999;margin-top:6px;width:160px}.status-option{border:none;border-radius:6px;padding:8px 10px;cursor:pointer;color:#fff;font-weight:600;width:100%;text-align:center}.status-option.done{background:#45a049}.status-option.mistakes{background:#fa8c16}.status-option.overdue{background:#d9363e}.status-option.clear{background:#6b7280}.picker-backdrop{position:absolute;top:0;right:0;bottom:0;left:0;z-index:9000;background:transparent}.task-item.completed:after{content:"✓";position:absolute;top:-5px;right:-5px;background:#fff;color:#4caf50;border-radius:50%;width:16px;height:16px;font-size:10px;display:flex;align-items:center;justify-content:center}.stats{display:flex;justify-content:space-between;align-items:center;margin-top:12px;padding:12px;background:#f8f9fa;border-radius:10px;transition:all .3s ease;overflow:hidden}.section.collapsed .stats{max-height:0;margin-top:0;padding-top:0;padding-bottom:0;opacity:0}.stat-item{text-align:center}.stat-number{font-size:1.3em;font-weight:700;color:#667eea}.stat-label{font-size:.9em;color:#666}.explanations-editor{margin-top:12px;background:#f8f9ff;border:1px solid #e3e6ff;border-radius:12px;padding:12px}.explanations-actions{display:flex;justify-content:flex-end;margin-top:12px}.explanations-grid{display:grid;grid-template-columns:1fr;gap:8px}.explanation-row{display:grid;grid-template-columns:40px 1fr;gap:8px;align-items:start}.explanation-num{width:36px;height:36px;border-radius:8px;background:#eef0ff;color:#4a56e2;display:flex;align-items:center;justify-content:center;font-weight:700}.explanation-input{width:100%;border:1px solid #e0e0e0;border-radius:8px;padding:8px 10px;font-family:inherit;resize:vertical;min-height:40px}.details{margin-top:12px;background:#f9fafb;border:1px dashed #e0e0e0;border-radius:10px;padding:12px}.detail-row{display:grid;grid-template-columns:40px 1fr;gap:8px;padding:6px 0;border-bottom:1px dashed #eaeaea}.detail-row:last-child{border-bottom:none}.detail-num{width:36px;height:36px;border-radius:8px;background:#eef0ff;color:#4a56e2;display:flex;align-items:center;justify-content:center;font-weight:700}.detail-text{color:#333;white-space:pre-wrap}.footer{background:#333;color:#fff;text-align:center;padding:16px}@media (max-width: 768px){.sections{padding:20px}.section-header{flex-direction:column;align-items:flex-start;gap:8px}.toggle-btn{align-self:flex-end}.tasks-grid{grid-template-columns:repeat(auto-fill,minmax(32px,1fr));gap:4px}.task-item{font-size:.85em;min-width:32px;min-height:32px}.stats{flex-direction:column;gap:8px}}@media (max-width: 480px){.section-header{flex-direction:column;align-items:flex-start;gap:8px}.toggle-btn{align-self:flex-end}.tasks-grid{grid-template-columns:repeat(auto-fill,minmax(28px,1fr));gap:3px}.task-item{font-size:.8em;min-width:28px;min-height:28px}}.admin-controls{display:grid;gap:8px;margin-bottom:12px}.search-section{display:flex;gap:8px;align-items:center}.search-input{flex:1}.student-select{min-width:260px}.action-buttons{display:flex;gap:8px;align-items:center;flex-wrap:wrap}.logs-container{overflow-x:auto}.logs-table{width:100%;border-collapse:collapse}.logs-table th{text-align:left;padding:8px}.logs-table td{padding:8px;border-top:1px solid #eee}@media (max-width: 768px){.admin-controls{gap:12px}.search-section{flex-direction:column}.student-select{min-width:auto;width:100%}.action-buttons{justify-content:center}}@media (max-width: 480px){.action-buttons{flex-direction:column;width:100%}.action-buttons .toggle-btn{width:100%}}.groups-modal{max-width:700px}.groups-modal-body{display:grid;gap:20px}.input-group{display:flex;gap:8px;align-items:center}.group-input,.group-select{flex:1}.members-list{display:grid;gap:8px;max-height:200px;overflow-y:auto}.member-item{display:flex;justify-content:space-between;align-items:center;padding:12px;background:#fff;border-radius:8px;border:1px solid #e2e8f0}.member-info{flex:1}.member-name{font-weight:600;color:#334155}.member-email{font-size:.9em;color:#64748b}.search-students-input{width:100%;margin-bottom:12px;padding:10px 12px;border-radius:8px;border:1px solid #d1d5db;font-size:14px}.sections.tasks{padding-inline:0}.search-students-input:focus{border-color:#3b82f6;outline:none;box-shadow:0 0 0 3px #3b82f61a}.students-list{max-height:300px;overflow-y:auto;border:1px solid #e5e7eb;border-radius:8px;margin-bottom:12px}.student-checkbox-item{display:flex;align-items:center;gap:12px;padding:12px;border-bottom:1px solid #f3f4f6;cursor:pointer;transition:background-color .2s}.student-checkbox-item:hover{background-color:#f8fafc}.student-checkbox-item:last-child{border-bottom:none}.student-checkbox{width:18px;height:18px;cursor:pointer;accent-color:#3b82f6}.student-info{flex:1}.student-name{font-weight:600;color:#334155;margin-bottom:2px}.student-email{font-size:.9em;color:#64748b}.empty-state{text-align:center;color:#64748b;font-style:italic;padding:20px}.categories-modal{max-width:600px}.categories-modal-body{display:grid;gap:20px}.category-form{display:flex;gap:8px;align-items:center;flex-wrap:wrap}.category-input{flex:2;min-width:200px}.tasks-input{flex:1;min-width:100px}.categories-list{display:grid;gap:8px;max-height:300px;overflow-y:auto}.category-item{display:flex;justify-content:space-between;align-items:center;padding:12px;background:#fff;border-radius:8px;border:1px solid #e2e8f0}.category-info{flex:1}.category-name{font-weight:600;color:#334155}.category-tasks{font-size:.9em;color:#64748b}.category-actions{display:flex;gap:6px}@media (max-width: 768px){.input-group,.category-form{flex-direction:column;align-items:stretch}.member-item,.category-item{flex-direction:column;align-items:stretch;gap:8px}.category-actions{justify-content:center}.students-list{max-height:250px}.student-checkbox-item{padding:10px;gap:10px}}