:root {
    --primary: #6366f1;
    --primary-dark: #4f46e5;
    --primary-light: #818cf8;
    --bg-gradient: linear-gradient(135deg, #f0f1f7 0%, #e8eaf6 100%);
    --card-bg: #ffffff;
    --text-primary: #1f2937;
    --text-secondary: #6b7280;
    --border-color: #e5e7eb;
    --success: #10b981;
    --warning: #f59e0b;
    --danger: #ef4444;
    --priority-high: #ef4444;
    --priority-medium: #f59e0b;
    --priority-low: #10b981;
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px 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);
    --radius: 12px;
    --radius-sm: 8px;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    background: var(--bg-gradient);
    min-height: 100vh;
    padding: 2rem 1rem;
    color: var(--text-primary);
}

.app-container {
    max-width: 560px;
    margin: 0 auto;
}

.app-header {
    text-align: center;
    margin-bottom: 2rem;
}

.logo {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    margin-bottom: 0.5rem;
}

.logo svg {
    color: var(--primary);
}

.logo h1 {
    font-size: 1.75rem;
    font-weight: 700;
    background: linear-gradient(135deg, var(--primary) 0%, var(--primary-light) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.tagline {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

/* Stats Section */
.stats-section {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 1rem;
    margin-bottom: 1.5rem;
}

.stat-card {
    background: var(--card-bg);
    padding: 1rem;
    border-radius: var(--radius);
    text-align: center;
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--border-color);
}

.stat-number {
    display: block;
    font-size: 1.75rem;
    font-weight: 700;
    color: var(--primary);
}

.stat-label {
    font-size: 0.75rem;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

/* Progress Bar */
.progress-container {
    background: var(--card-bg);
    padding: 1rem 1.25rem;
    border-radius: var(--radius);
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--border-color);
    margin-bottom: 1.5rem;
}

.progress-info {
    display: flex;
    justify-content: space-between;
    font-size: 0.875rem;
    font-weight: 500;
    margin-bottom: 0.5rem;
}

.progress-bar {
    height: 8px;
    background: var(--border-color);
    border-radius: 4px;
    overflow: hidden;
}

.progress-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--primary) 0%, var(--primary-light) 100%);
    border-radius: 4px;
    width: 0%;
    transition: width 0.4s ease;
}

/* Filter Section */
.filter-section {
    display: flex;
    gap: 0.5rem;
    margin-bottom: 1.5rem;
    flex-wrap: wrap;
}

.filter-btn {
    padding: 0.5rem 1rem;
    border: 1px solid var(--border-color);
    background: var(--card-bg);
    border-radius: 20px;
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--text-secondary);
    cursor: pointer;
    transition: all 0.2s ease;
}

.filter-btn:hover {
    border-color: var(--primary);
    color: var(--primary);
}

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

/* Task Form */
.task-form {
    background: var(--card-bg);
    padding: 1.25rem;
    border-radius: var(--radius);
    box-shadow: var(--shadow-md);
    border: 1px solid var(--border-color);
    margin-bottom: 1.5rem;
}

.input-row {
    display: flex;
    gap: 0.75rem;
    margin-bottom: 1rem;
}

.task-form input[type="text"] {
    flex: 1;
    padding: 0.75rem 1rem;
    border: 2px solid var(--border-color);
    border-radius: var(--radius-sm);
    font-size: 0.95rem;
    transition: border-color 0.2s ease;
    outline: none;
}

.task-form input[type="text"]:focus {
    border-color: var(--primary);
}

.add-btn {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.75rem 1.25rem;
    background: var(--primary);
    color: white;
    border: none;
    border-radius: var(--radius-sm);
    font-size: 0.95rem;
    font-weight: 600;
    cursor: pointer;
    transition: background 0.2s ease;
}

.add-btn:hover {
    background: var(--primary-dark);
}

.options-row {
    display: flex;
    gap: 1rem;
}

.select-group {
    flex: 1;
}

.select-group label {
    display: block;
    font-size: 0.75rem;
    font-weight: 500;
    color: var(--text-secondary);
    margin-bottom: 0.35rem;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.select-group select {
    width: 100%;
    padding: 0.5rem 0.75rem;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    font-size: 0.875rem;
    background: #f9fafb;
    cursor: pointer;
    outline: none;
    transition: border-color 0.2s ease;
}

.select-group select:focus {
    border-color: var(--primary);
}

/* Task List */
.task-list {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.task-item {
    background: var(--card-bg);
    padding: 1rem 1.25rem;
    border-radius: var(--radius);
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--border-color);
    display: flex;
    align-items: center;
    gap: 1rem;
    transition: all 0.2s ease;
    animation: slideIn 0.3s ease;
}

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

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

.task-item.completed {
    opacity: 0.6;
}

.task-item.completed .task-text {
    text-decoration: line-through;
    color: var(--text-secondary);
}

.task-checkbox {
    width: 22px;
    height: 22px;
    border: 2px solid var(--border-color);
    border-radius: 6px;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.2s ease;
    flex-shrink: 0;
}

.task-checkbox:hover {
    border-color: var(--primary);
}

.task-checkbox.checked {
    background: var(--success);
    border-color: var(--success);
}

.task-checkbox.checked svg {
    opacity: 1;
}

.task-checkbox svg {
    width: 14px;
    height: 14px;
    color: white;
    opacity: 0;
    transition: opacity 0.2s ease;
}

.task-content {
    flex: 1;
    min-width: 0;
}

.task-text {
    font-size: 0.95rem;
    font-weight: 500;
    margin-bottom: 0.25rem;
    word-break: break-word;
}

.task-meta {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    font-size: 0.75rem;
}

.category-tag {
    padding: 0.2rem 0.5rem;
    border-radius: 4px;
    font-weight: 500;
    text-transform: capitalize;
}

.category-tag.work {
    background: #e0e7ff;
    color: #4338ca;
}

.category-tag.personal {
    background: #d1fae5;
    color: #065f46;
}

.category-tag.shopping {
    background: #fef3c7;
    color: #92400e;
}

.priority-tag {
    padding: 0.2rem 0.5rem;
    border-radius: 4px;
    font-weight: 500;
    text-transform: capitalize;
}

.priority-tag.high {
    background: #fee2e2;
    color: var(--priority-high);
}

.priority-tag.medium {
    background: #fef3c7;
    color: var(--priority-medium);
}

.priority-tag.low {
    background: #d1fae5;
    color: var(--priority-low);
}

.delete-btn {
    width: 32px;
    height: 32px;
    border: none;
    background: transparent;
    color: var(--text-secondary);
    cursor: pointer;
    border-radius: var(--radius-sm);
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.2s ease;
    flex-shrink: 0;
}

.delete-btn:hover {
    background: #fee2e2;
    color: var(--danger);
}

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

.empty-state svg {
    margin-bottom: 1rem;
    opacity: 0.5;
}

.empty-state p {
    font-size: 0.95rem;
}

/* Responsive */
@media (max-width: 480px) {
    .stats-section {
        grid-template-columns: 1fr;
    }
    
    .options-row {
        flex-direction: column;
        gap: 0.75rem;
    }
    
    .task-meta {
        flex-wrap: wrap;
    }
}