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

:root {
    /* Color Palette */
    --primary-dark: #05386B;
    --primary-medium: #379683;
    --primary-light: #5CDB95;
    --secondary-light: #8EE4AF;
    --background-light: #EDF5E1;
    
    /* Theme Colors */
    --bg-primary: var(--background-light);
    --bg-secondary: #ffffff;
    --text-primary: var(--primary-dark);
    --text-secondary: #6c757d;
    --border-color: #dee2e6;
    
    /* Gradients */
    --gradient-primary: linear-gradient(135deg, var(--primary-dark) 0%, var(--primary-medium) 100%);
    --gradient-secondary: linear-gradient(135deg, var(--primary-medium) 0%, var(--primary-light) 100%);
    --gradient-accent: linear-gradient(135deg, var(--primary-light) 0%, var(--secondary-light) 100%);
    
    /* Shadows */
    --shadow-sm: 0 2px 4px rgba(5, 56, 107, 0.1);
    --shadow-md: 0 4px 6px rgba(5, 56, 107, 0.1);
    --shadow-lg: 0 10px 15px rgba(5, 56, 107, 0.1);
    
    /* Transitions */
    --transition-fast: 0.2s ease;
    --transition-normal: 0.3s ease;
    --transition-slow: 0.5s ease;
}

/* Dark Theme Variables */
[data-theme="dark"] {
    --bg-primary: #1a1a1a;
    --bg-secondary: #2d2d2d;
    --text-primary: #ffffff;
    --text-secondary: #b0b0b0;
    --border-color: #404040;
}

/* Base Styles */
body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    transition: background-color var(--transition-normal), color var(--transition-normal);
}

/* Header Styles */
.bg-primary-gradient {
    background: var(--gradient-primary) !important;
    box-shadow: var(--shadow-md);
}

.navbar-brand {
    font-size: 1.5rem;
    font-weight: 700;
}

.navbar-nav .nav-link {
    font-weight: 500;
    transition: color var(--transition-fast);
    border-radius: 0.375rem;
    margin: 0 0.25rem;
    padding: 0.5rem 1rem !important;
}

.navbar-nav .nav-link:hover,
.navbar-nav .nav-link.active {
    background: rgba(255, 255, 255, 0.1);
    color: #ffffff !important;
}

/* Content Sections */
.content-section {
    display: none;
    animation: fadeIn var(--transition-normal);
}

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

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

.section-title {
    color: var(--primary-dark);
    font-weight: 700;
    margin-bottom: 2rem;
}

[data-theme="dark"] .section-title {
    color: var(--primary-light);
}

/* Card Styles */
.card {
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 0.75rem;
    box-shadow: var(--shadow-sm);
    transition: all var(--transition-normal);
}

.card:hover {
    box-shadow: var(--shadow-md);
    transform: translateY(-2px);
}

.card-header {
    border-bottom: 1px solid var(--border-color);
    border-radius: 0.75rem 0.75rem 0 0 !important;
    font-weight: 600;
}

.bg-gradient-primary {
    background: var(--gradient-primary) !important;
}

.bg-gradient-secondary {
    background: var(--gradient-secondary) !important;
}

.bg-gradient-success {
    background: var(--gradient-accent) !important;
}

/* Stats Cards */
.stats-card {
    background: var(--bg-secondary);
    border: none;
    border-radius: 1rem;
    box-shadow: var(--shadow-md);
    transition: all var(--transition-normal);
}

.stats-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
}

.stats-icon {
    font-size: 2.5rem;
    margin-bottom: 1rem;
}

.stats-number {
    font-size: 2rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 0.5rem;
}

.stats-label {
    color: var(--text-secondary);
    font-weight: 500;
    margin-bottom: 0;
}

/* Subject Cards */
.subject-card {
    background: var(--bg-secondary);
    border: none;
    border-radius: 1rem;
    box-shadow: var(--shadow-md);
    transition: all var(--transition-normal);
    position: relative;
    overflow: hidden;
}

.subject-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: var(--gradient-primary);
}

.subject-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
}

.subject-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1rem;
}

.subject-title {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--text-primary);
    margin: 0;
}

.subject-actions {
    display: flex;
    gap: 0.5rem;
}

.btn-icon {
    width: 2.5rem;
    height: 2.5rem;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    border: none;
    transition: all var(--transition-fast);
}

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

.btn-edit:hover {
    background: var(--primary-medium);
    transform: scale(1.1);
}

.btn-delete {
    background: #dc3545;
    color: white;
}

.btn-delete:hover {
    background: #c82333;
    transform: scale(1.1);
}

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

.btn-add-task:hover {
    background: var(--primary-dark);
    transform: scale(1.1);
}

/* Progress Bars */
.progress {
    height: 0.75rem;
    border-radius: 0.5rem;
    background: var(--border-color);
}

.progress-bar {
    background: var(--gradient-secondary);
    border-radius: 0.5rem;
    transition: width var(--transition-normal);
}

.progress-info {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 0.5rem;
}

.progress-label {
    font-weight: 600;
    color: var(--text-primary);
}

.progress-value {
    font-weight: 700;
    color: var(--primary-medium);
}

/* Task Lists */
.task-list {
    max-height: 400px;
    overflow-y: auto;
}

.task-item {
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 0.5rem;
    padding: 1rem;
    margin-bottom: 0.75rem;
    transition: all var(--transition-fast);
    position: relative;
}

.task-item:hover {
    box-shadow: var(--shadow-sm);
    transform: translateX(5px);
}

.task-item.completed {
    opacity: 0.7;
    background: var(--background-light);
}

[data-theme="dark"] .task-item.completed {
    background: rgba(92, 219, 149, 0.1);
}

.task-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: 0.5rem;
}

.task-title {
    font-weight: 600;
    color: var(--text-primary);
    margin: 0;
}

.task-title.completed {
    text-decoration: line-through;
}

.task-meta {
    display: flex;
    gap: 1rem;
    font-size: 0.875rem;
    color: var(--text-secondary);
    margin-bottom: 0.5rem;
}

.task-actions {
    display: flex;
    gap: 0.5rem;
}

.task-checkbox {
    width: 1.25rem;
    height: 1.25rem;
    margin-right: 0.5rem;
}

/* Priority Indicators */
.priority-indicator {
    width: 0.75rem;
    height: 0.75rem;
    border-radius: 50%;
    display: inline-block;
    margin-right: 0.5rem;
}

.priority-high {
    background: #dc3545;
}

.priority-medium {
    background: #ffc107;
}

.priority-low {
    background: #28a745;
}

/* Calendar Styles */
.calendar-grid {
    display: grid;
    grid-template-columns: repeat(7, 1fr);
    gap: 1px;
    background: var(--border-color);
    border-radius: 0.5rem;
    overflow: hidden;
}

.calendar-header {
    background: var(--primary-dark);
    color: white;
    padding: 1rem;
    text-align: center;
    font-weight: 600;
}

.calendar-day {
    background: var(--bg-secondary);
    min-height: 100px;
    padding: 0.5rem;
    position: relative;
    transition: background-color var(--transition-fast);
}

.calendar-day:hover {
    background: var(--background-light);
}

[data-theme="dark"] .calendar-day:hover {
    background: rgba(55, 150, 131, 0.1);
}

.calendar-day.other-month {
    opacity: 0.3;
}

.calendar-day.today {
    background: var(--primary-light);
    color: white;
    font-weight: 700;
}

.calendar-day-number {
    font-weight: 600;
    margin-bottom: 0.25rem;
}

.calendar-tasks {
    font-size: 0.75rem;
}

.calendar-task {
    background: var(--primary-medium);
    color: white;
    padding: 0.125rem 0.25rem;
    border-radius: 0.25rem;
    margin-bottom: 0.125rem;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

/* Form Styles */
.form-control,
.form-select {
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    color: var(--text-primary);
    transition: all var(--transition-fast);
}

.form-control:focus,
.form-select:focus {
    background: var(--bg-secondary);
    border-color: var(--primary-medium);
    box-shadow: 0 0 0 0.2rem rgba(55, 150, 131, 0.25);
    color: var(--text-primary);
}

.form-label {
    color: var(--text-primary);
    font-weight: 600;
}

/* Button Styles */
.btn {
    border-radius: 0.5rem;
    font-weight: 600;
    transition: all var(--transition-fast);
}

.btn-primary {
    background: var(--gradient-primary);
    border: none;
}

.btn-primary:hover {
    background: var(--gradient-secondary);
    transform: translateY(-1px);
    box-shadow: var(--shadow-sm);
}

.btn-success {
    background: var(--gradient-accent);
    border: none;
}

.btn-success:hover {
    background: var(--gradient-secondary);
    transform: translateY(-1px);
}

.btn-outline-primary {
    border-color: var(--primary-medium);
    color: var(--primary-medium);
}

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

.btn-outline-light {
    border-color: rgba(255, 255, 255, 0.5);
    color: rgba(255, 255, 255, 0.8);
}

.btn-outline-light:hover {
    background: rgba(255, 255, 255, 0.1);
    border-color: rgba(255, 255, 255, 0.8);
    color: white;
}

/* Modal Styles */
.modal-content {
    background: var(--bg-secondary);
    border: none;
    border-radius: 1rem;
    box-shadow: var(--shadow-lg);
}

.modal-header {
    border-bottom: 1px solid var(--border-color);
    border-radius: 1rem 1rem 0 0;
}

.modal-footer {
    border-top: 1px solid var(--border-color);
    border-radius: 0 0 1rem 1rem;
}

.modal-title {
    color: var(--text-primary);
    font-weight: 700;
}

/* Toast Styles */
.toast {
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 0.75rem;
    box-shadow: var(--shadow-lg);
}

.toast-header {
    background: var(--background-light);
    border-bottom: 1px solid var(--border-color);
    border-radius: 0.75rem 0.75rem 0 0;
}

[data-theme="dark"] .toast-header {
    background: var(--bg-primary);
}

.toast-body {
    color: var(--text-primary);
}

/* Alert Styles */
.alert {
    border: none;
    border-radius: 0.75rem;
    box-shadow: var(--shadow-sm);
}

.alert-info {
    background: rgba(92, 219, 149, 0.1);
    color: var(--primary-dark);
}

.alert-warning {
    background: rgba(255, 193, 7, 0.1);
    color: #856404;
}

.alert-success {
    background: rgba(40, 167, 69, 0.1);
    color: #155724;
}

/* Responsive Design */
@media (max-width: 768px) {
    .container-fluid {
        padding-left: 1rem;
        padding-right: 1rem;
    }
    
    .stats-card {
        margin-bottom: 1rem;
    }
    
    .subject-card {
        margin-bottom: 1rem;
    }
    
    .calendar-day {
        min-height: 80px;
        padding: 0.25rem;
    }
    
    .task-meta {
        flex-direction: column;
        gap: 0.25rem;
    }
    
    .task-actions {
        flex-direction: column;
        width: 100%;
        margin-top: 0.5rem;
    }
    
    .btn-group {
        flex-direction: column;
    }
    
    .navbar-nav {
        text-align: center;
        margin-top: 1rem;
    }
    
    .section-title {
        font-size: 1.5rem;
    }
}

@media (max-width: 576px) {
    .calendar-grid {
        grid-template-columns: 1fr;
    }
    
    .calendar-day {
        min-height: 60px;
        display: flex;
        justify-content: space-between;
        align-items: center;
    }
    
    .calendar-tasks {
        display: none;
    }
    
    .stats-number {
        font-size: 1.5rem;
    }
    
    .stats-icon {
        font-size: 2rem;
    }
    
    .modal-dialog {
        margin: 0.5rem;
    }
}

/* Accessibility */
@media (prefers-reduced-motion: reduce) {
    * {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}

/* Focus Styles */
.btn:focus,
.form-control:focus,
.form-select:focus {
    outline: 2px solid var(--primary-medium);
    outline-offset: 2px;
}

/* Print Styles */
@media print {
    .navbar,
    .modal,
    .toast-container,
    .btn,
    footer {
        display: none !important;
    }
    
    .content-section {
        display: block !important;
    }
    
    .card {
        box-shadow: none;
        border: 1px solid #000;
    }
    
    body {
        background: white;
        color: black;
    }
}

/* Scrollbar Styles */
::-webkit-scrollbar {
    width: 8px;
}

::-webkit-scrollbar-track {
    background: var(--bg-primary);
}

::-webkit-scrollbar-thumb {
    background: var(--primary-medium);
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--primary-dark);
}

/* Loading Animation */
.loading {
    display: inline-block;
    width: 20px;
    height: 20px;
    border: 3px solid rgba(255, 255, 255, 0.3);
    border-radius: 50%;
    border-top-color: #fff;
    animation: spin 1s ease-in-out infinite;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

/* Empty State */
.empty-state {
    text-align: center;
    padding: 3rem 1rem;
    color: var(--text-secondary);
}

.empty-state i {
    font-size: 4rem;
    margin-bottom: 1rem;
    opacity: 0.5;
}

.empty-state h3 {
    margin-bottom: 0.5rem;
    color: var(--text-primary);
}

.empty-state p {
    margin-bottom: 1.5rem;
}

/* Utility Classes */
.text-gradient {
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.bg-blur {
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
}

.shadow-custom {
    box-shadow: var(--shadow-lg);
}

.border-gradient {
    border: 2px solid transparent;
    background: linear-gradient(var(--bg-secondary), var(--bg-secondary)) padding-box,
                var(--gradient-primary) border-box;
}

/* Animation Classes */
.fade-in {
    animation: fadeIn var(--transition-normal);
}

.slide-up {
    animation: slideUp var(--transition-normal);
}

@keyframes slideUp {
    from { transform: translateY(20px); opacity: 0; }
    to { transform: translateY(0); opacity: 1; }
}

.bounce-in {
    animation: bounceIn var(--transition-slow);
}

@keyframes bounceIn {
    0% { transform: scale(0.3); opacity: 0; }
    50% { transform: scale(1.05); }
    70% { transform: scale(0.9); }
    100% { transform: scale(1); opacity: 1; }
}