/* CSS Custom Properties for Dark Theme */
:root {
    --bg-primary: #000000;
    --bg-secondary: #1a1a1a;
    --bg-tertiary: #333333;
    --text-primary: #ffffff;
    --text-secondary: #f8f9fa;
    --text-muted: #999999;
    --accent-primary: #4a90e2;
    --accent-secondary: #357abd;
    --border-color: #444444;
    --shadow-color: rgba(0, 0, 0, 0.5);
    --success-color: #28a745;
    --warning-color: #ffc107;
    --danger-color: #dc3545;
    --info-color: #17a2b8;
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    background-color: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100vh;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 20px;
}

/* Header Styles */
.header {
    text-align: center;
    margin-bottom: 40px;
    padding: 20px 0;
    border-bottom: 2px solid var(--border-color);
}

.header h1 {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 10px;
    background: linear-gradient(135deg, var(--accent-primary), var(--accent-secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.subtitle {
    color: var(--text-muted);
    font-size: 1.1rem;
}

/* Main Content Layout */
.main-content {
    display: grid;
    grid-template-columns: 1fr 2fr;
    gap: 40px;
    align-items: start;
}

/* Form Styles */
.task-form-section {
    background-color: var(--bg-secondary);
    padding: 30px;
    border-radius: 12px;
    border: 1px solid var(--border-color);
    box-shadow: 0 4px 6px var(--shadow-color);
}

.task-form-section h2 {
    margin-bottom: 20px;
    color: var(--text-primary);
    font-size: 1.5rem;
}

.form-group {
    margin-bottom: 20px;
}

.form-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 15px;
}

.form-group label {
    display: block;
    margin-bottom: 8px;
    color: var(--text-secondary);
    font-weight: 500;
}

.form-group input,
.form-group textarea,
.form-group select {
    width: 100%;
    padding: 12px 16px;
    background-color: var(--bg-tertiary);
    border: 2px solid var(--border-color);
    border-radius: 8px;
    color: var(--text-primary);
    font-size: 14px;
    transition: border-color 0.3s ease, box-shadow 0.3s ease;
}

.form-group input:focus,
.form-group textarea:focus,
.form-group select:focus {
    outline: none;
    border-color: var(--accent-primary);
    box-shadow: 0 0 0 3px rgba(74, 144, 226, 0.1);
}

.form-group textarea {
    resize: vertical;
    min-height: 80px;
}

/* Button Styles */
.btn {
    padding: 12px 24px;
    border: none;
    border-radius: 8px;
    font-size: 14px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.btn-primary {
    background: linear-gradient(135deg, var(--accent-primary), var(--accent-secondary));
    color: white;
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(74, 144, 226, 0.3);
}

.btn-secondary {
    background-color: var(--bg-tertiary);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
}

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

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

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

/* Tasks Section */
.tasks-section h2 {
    color: var(--text-primary);
    margin-bottom: 20px;
    font-size: 1.5rem;
}

.tasks-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 20px;
}

.filter-controls {
    display: flex;
    gap: 15px;
    margin-bottom: 20px;
}

.filter-controls select {
    padding: 8px 12px;
    background-color: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 6px;
    color: var(--text-primary);
}

/* Task Cards */
.tasks-container {
    display: grid;
    gap: 15px;
}

.task-card {
    background-color: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 20px;
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.task-card:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px var(--shadow-color);
}

.task-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: 10px;
}

.task-title {
    font-size: 1.2rem;
    font-weight: 600;
    color: var(--text-primary);
    margin: 0;
}

.task-priority {
    padding: 4px 8px;
    border-radius: 4px;
    font-size: 0.75rem;
    font-weight: 600;
    text-transform: uppercase;
}

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

.priority-medium {
    background-color: var(--warning-color);
    color: black;
}

.priority-low {
    background-color: var(--info-color);
    color: white;
}

.task-description {
    color: var(--text-muted);
    margin-bottom: 15px;
    line-height: 1.5;
}

.task-meta {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 15px;
    font-size: 0.9rem;
    color: var(--text-muted);
}

.task-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 5px;
    margin-bottom: 15px;
}

.tag {
    background-color: var(--bg-tertiary);
    color: var(--text-secondary);
    padding: 2px 8px;
    border-radius: 12px;
    font-size: 0.8rem;
}

.task-actions {
    display: flex;
    gap: 10px;
}

.task-actions .btn {
    padding: 6px 12px;
    font-size: 0.8rem;
}

/* Status Styles */
.status-pending {
    border-left: 4px solid var(--warning-color);
}

.status-in-progress {
    border-left: 4px solid var(--info-color);
}

.status-completed {
    border-left: 4px solid var(--success-color);
}

/* Notification Styles */
.notification {
    position: fixed;
    top: 20px;
    right: 20px;
    padding: 15px 20px;
    border-radius: 8px;
    color: white;
    font-weight: 500;
    z-index: 1000;
    transform: translateX(100%);
    transition: transform 0.3s ease;
}

.notification.show {
    transform: translateX(0);
}

.notification.hidden {
    display: none;
}

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

.notification.error {
    background-color: var(--danger-color);
}

.notification.info {
    background-color: var(--info-color);
}

/* Loading and Empty States */
.loading {
    text-align: center;
    color: var(--text-muted);
    padding: 40px;
    font-style: italic;
}

.empty-state {
    text-align: center;
    color: var(--text-muted);
    padding: 40px;
}

.empty-state h3 {
    margin-bottom: 10px;
    color: var(--text-secondary);
}

/* Responsive Design */
@media (max-width: 768px) {
    .main-content {
        grid-template-columns: 1fr;
        gap: 30px;
    }
    
    .form-row {
        grid-template-columns: 1fr;
    }
    
    .tasks-header {
        flex-direction: column;
        align-items: stretch;
        gap: 15px;
    }
    
    .filter-controls {
        flex-direction: column;
    }
    
    .task-header {
        flex-direction: column;
        align-items: flex-start;
        gap: 10px;
    }
    
    .task-actions {
        flex-wrap: wrap;
    }
    
    .container {
        padding: 15px;
    }
    
    .header h1 {
        font-size: 2rem;
    }
}

@media (max-width: 480px) {
    .task-form-section {
        padding: 20px;
    }
    
    .task-card {
        padding: 15px;
    }
    
    .task-meta {
        flex-direction: column;
        align-items: flex-start;
        gap: 5px;
    }
}

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

/* Focus Styles for Keyboard Navigation */
.btn:focus,
input:focus,
textarea:focus,
select:focus {
    outline: 2px solid var(--accent-primary);
    outline-offset: 2px;
}

/* High Contrast Mode Support */
@media (prefers-contrast: high) {
    :root {
        --border-color: #666666;
        --bg-secondary: #111111;
        --bg-tertiary: #222222;
    }
}