/* Reset and Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --primary-color: #2563eb;
    --secondary-color: #64748b;
    --success-color: #10b981;
    --warning-color: #f59e0b;
    --danger-color: #ef4444;
    --dark-color: #1e293b;
    --light-color: #f8fafc;
    --border-color: #e2e8f0;
    --text-primary: #0f172a;
    --text-secondary: #64748b;
    --shadow: 0 1px 3px 0 rgba(0, 0, 0, 0.1), 0 1px 2px 0 rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
}

body {
    font-family: 'Inter', sans-serif;
    background-color: var(--light-color);
    color: var(--text-primary);
    line-height: 1.6;
}

/* Header */
.header {
    background: white;
    border-bottom: 1px solid var(--border-color);
    box-shadow: var(--shadow);
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    height: 70px;
}

.header-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0 2rem;
    height: 100%;
}

.logo {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-color);
}

.logo i {
    font-size: 2rem;
}

.user-info {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.user-name {
    font-weight: 500;
    color: var(--text-primary);
}

.user-avatar {
    width: 40px;
    height: 40px;
    background: var(--primary-color);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
}

.logout-btn {
    background: none;
    border: none;
    color: var(--text-secondary);
    cursor: pointer;
    padding: 0.5rem;
    border-radius: 0.375rem;
    transition: all 0.2s;
}

.logout-btn:hover {
    background: var(--light-color);
    color: var(--danger-color);
}

/* Sidebar */
.sidebar {
    position: fixed;
    top: 70px;
    left: 0;
    width: 250px;
    height: calc(100vh - 70px);
    background: white;
    border-right: 1px solid var(--border-color);
    overflow-y: auto;
    z-index: 999;
}

.sidebar-nav {
    padding: 1rem 0;
}

.nav-list {
    list-style: none;
}

.nav-item {
    margin-bottom: 0.25rem;
}

.nav-link {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 0.75rem 1.5rem;
    color: var(--text-secondary);
    text-decoration: none;
    transition: all 0.2s;
    border-right: 3px solid transparent;
}

.nav-link:hover {
    background: var(--light-color);
    color: var(--primary-color);
}

.nav-link.active {
    background: #eff6ff;
    color: var(--primary-color);
    border-right-color: var(--primary-color);
}

.nav-link i {
    width: 20px;
    text-align: center;
}

/* Main Content */
.main-content {
    margin-left: 250px;
    margin-top: 70px;
    padding: 2rem;
    min-height: calc(100vh - 70px);
}

.content-section {
    display: none;
}

.content-section.active {
    display: block;
}

.section-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 2rem;
}

.section-header h1 {
    font-size: 2rem;
    font-weight: 700;
    color: var(--text-primary);
}

.section-header p {
    color: var(--text-secondary);
    margin-top: 0.5rem;
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: 0.5rem;
    font-weight: 500;
    text-decoration: none;
    cursor: pointer;
    transition: all 0.2s;
    font-size: 0.875rem;
}

.btn-primary {
    background: var(--primary-color);
    color: white;
}

.btn-primary:hover {
    background: #1d4ed8;
}

.btn-secondary {
    background: var(--secondary-color);
    color: white;
}

.btn-secondary:hover {
    background: #475569;
}

.btn-success {
    background: var(--success-color);
    color: white;
}

.btn-warning {
    background: var(--warning-color);
    color: white;
}

.btn-danger {
    background: var(--danger-color);
    color: white;
}

.btn-sm {
    padding: 0.5rem 1rem;
    font-size: 0.75rem;
}

/* Stats Grid */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1.5rem;
    margin-bottom: 2rem;
}

.stat-card {
    background: white;
    padding: 1.5rem;
    border-radius: 0.75rem;
    box-shadow: var(--shadow);
    display: flex;
    align-items: center;
    gap: 1rem;
}

.stat-icon {
    width: 60px;
    height: 60px;
    background: var(--primary-color);
    border-radius: 0.75rem;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 1.5rem;
}

.stat-info h3 {
    font-size: 2rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 0.25rem;
}

.stat-info p {
    color: var(--text-secondary);
    font-size: 0.875rem;
}

/* Dashboard Grid */
.dashboard-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(400px, 1fr));
    gap: 2rem;
}

.dashboard-card {
    background: white;
    padding: 1.5rem;
    border-radius: 0.75rem;
    box-shadow: var(--shadow);
}

.dashboard-card h3 {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

.activity-list {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.activity-item {
    display: flex;
    align-items: center;
    gap: 1rem;
    padding: 0.75rem;
    background: var(--light-color);
    border-radius: 0.5rem;
}

.activity-item i {
    color: var(--primary-color);
    width: 20px;
}

.activity-item span {
    flex: 1;
    font-size: 0.875rem;
}

.activity-item small {
    color: var(--text-secondary);
    font-size: 0.75rem;
}

.quick-actions {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 1rem;
}

.action-btn {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.5rem;
    padding: 1rem;
    background: var(--light-color);
    border: 1px solid var(--border-color);
    border-radius: 0.5rem;
    cursor: pointer;
    transition: all 0.2s;
    text-align: center;
}

.action-btn:hover {
    background: var(--primary-color);
    color: white;
    border-color: var(--primary-color);
}

.action-btn i {
    font-size: 1.5rem;
}

/* Table Styles */
.table-container {
    background: white;
    border-radius: 0.75rem;
    box-shadow: var(--shadow);
    overflow: hidden;
}

.table-controls {
    display: flex;
    gap: 1rem;
    padding: 1.5rem;
    border-bottom: 1px solid var(--border-color);
}

.search-input,
.filter-select,
.date-input {
    padding: 0.75rem;
    border: 1px solid var(--border-color);
    border-radius: 0.5rem;
    font-size: 0.875rem;
}

.search-input {
    flex: 1;
}

.data-table {
    width: 100%;
    border-collapse: collapse;
}

.data-table th,
.data-table td {
    padding: 1rem;
    text-align: left;
    border-bottom: 1px solid var(--border-color);
}

.data-table th {
    background: var(--light-color);
    font-weight: 600;
    color: var(--text-primary);
}

.data-table tbody tr:hover {
    background: var(--light-color);
}

/* Grid Layouts */
.classes-grid,
.subjects-grid,
.reports-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 1.5rem;
}

.class-card,
.subject-card,
.report-card {
    background: white;
    padding: 1.5rem;
    border-radius: 0.75rem;
    box-shadow: var(--shadow);
    transition: all 0.2s;
}

.class-card:hover,
.subject-card:hover,
.report-card:hover {
    box-shadow: var(--shadow-lg);
    transform: translateY(-2px);
}

.class-card h3,
.subject-card h3,
.report-card h3 {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
    color: var(--text-primary);
}

.class-card p,
.subject-card p,
.report-card p {
    color: var(--text-secondary);
    margin-bottom: 1rem;
}

/* Attendance Styles */
.attendance-controls,
.grade-controls {
    display: flex;
    gap: 1rem;
    margin-bottom: 1.5rem;
    align-items: center;
}

.attendance-container,
.grades-container {
    background: white;
    border-radius: 0.75rem;
    box-shadow: var(--shadow);
    padding: 1.5rem;
}

.attendance-list {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.attendance-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem;
    background: var(--light-color);
    border-radius: 0.5rem;
}

.attendance-controls-item {
    display: flex;
    gap: 0.5rem;
}

.attendance-btn {
    padding: 0.5rem 1rem;
    border: none;
    border-radius: 0.375rem;
    cursor: pointer;
    font-size: 0.75rem;
    font-weight: 500;
}

.attendance-btn.present {
    background: var(--success-color);
    color: white;
}

.attendance-btn.absent {
    background: var(--danger-color);
    color: white;
}

.attendance-btn.late {
    background: var(--warning-color);
    color: white;
}

/* Modal Styles */
.modal {
    display: none;
    position: fixed;
    z-index: 2000;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.5);
}

.modal-content {
    background-color: white;
    margin: 5% auto;
    padding: 0;
    border-radius: 0.75rem;
    width: 90%;
    max-width: 500px;
    box-shadow: var(--shadow-lg);
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1.5rem;
    border-bottom: 1px solid var(--border-color);
}

.modal-header h2 {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--text-primary);
}

.close {
    color: var(--text-secondary);
    font-size: 2rem;
    font-weight: bold;
    cursor: pointer;
    line-height: 1;
}

.close:hover {
    color: var(--danger-color);
}

.modal-form {
    padding: 1.5rem;
}

.form-group {
    margin-bottom: 1rem;
}

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 500;
    color: var(--text-primary);
}

.form-group input,
.form-group select,
.form-group textarea {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid var(--border-color);
    border-radius: 0.5rem;
    font-size: 0.875rem;
    transition: border-color 0.2s;
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

.modal-actions {
    display: flex;
    gap: 1rem;
    justify-content: flex-end;
    margin-top: 1.5rem;
}

/* Responsive Design */
@media (max-width: 1024px) {
    .sidebar {
        transform: translateX(-100%);
        transition: transform 0.3s;
    }
    
    .sidebar.open {
        transform: translateX(0);
    }
    
    .main-content {
        margin-left: 0;
    }
    
    .stats-grid {
        grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    }
    
    .dashboard-grid {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 768px) {
    .main-content {
        padding: 1rem;
    }
    
    .section-header {
        flex-direction: column;
        align-items: flex-start;
        gap: 1rem;
    }
    
    .table-controls {
        flex-direction: column;
    }
    
    .attendance-controls,
    .grade-controls {
        flex-direction: column;
        align-items: stretch;
    }
    
    .quick-actions {
        grid-template-columns: 1fr;
    }
    
    .classes-grid,
    .subjects-grid,
    .reports-grid {
        grid-template-columns: 1fr;
    }
    
    .modal-content {
        width: 95%;
        margin: 10% auto;
    }
}

@media (max-width: 480px) {
    .header-content {
        padding: 0 1rem;
    }
    
    .logo {
        font-size: 1.25rem;
    }
    
    .stats-grid {
        grid-template-columns: 1fr;
    }
    
    .stat-card {
        padding: 1rem;
    }
    
    .stat-icon {
        width: 50px;
        height: 50px;
        font-size: 1.25rem;
    }
    
    .stat-info h3 {
        font-size: 1.5rem;
    }
}

/* Utility Classes */
.text-center {
    text-align: center;
}

.text-right {
    text-align: right;
}

.mb-1 {
    margin-bottom: 0.25rem;
}

.mb-2 {
    margin-bottom: 0.5rem;
}

.mb-3 {
    margin-bottom: 0.75rem;
}

.mb-4 {
    margin-bottom: 1rem;
}

.mt-1 {
    margin-top: 0.25rem;
}

.mt-2 {
    margin-top: 0.5rem;
}

.mt-3 {
    margin-top: 0.75rem;
}

.mt-4 {
    margin-top: 1rem;
}

.p-1 {
    padding: 0.25rem;
}

.p-2 {
    padding: 0.5rem;
}

.p-3 {
    padding: 0.75rem;
}

.p-4 {
    padding: 1rem;
}

.hidden {
    display: none;
}

.visible {
    display: block;
}

.flex {
    display: flex;
}

.flex-col {
    flex-direction: column;
}

.items-center {
    align-items: center;
}

.justify-center {
    justify-content: center;
}

.justify-between {
    justify-content: space-between;
}

.gap-1 {
    gap: 0.25rem;
}

.gap-2 {
    gap: 0.5rem;
}

.gap-3 {
    gap: 0.75rem;
}

.gap-4 {
    gap: 1rem;
}