:root {
    --primary-color: #4f46e5;
    --primary-hover: #4338ca;
    --secondary-color: #6b7280;
    --success-color: #10b981;
    --warning-color: #f59e0b;
    --danger-color: #ef4444;
    --bg-color: #f9fafb;
    --card-bg: #ffffff;
    --text-color: #111827;
    --text-muted: #6b7280;
    --border-color: #e5e7eb;
    --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);
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    line-height: 1.6;
    padding: 20px;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    background-color: var(--card-bg);
    border-radius: 12px;
    padding: 40px;
    box-shadow: var(--shadow-lg);
}

h1 {
    font-size: 2.5rem;
    margin-bottom: 8px;
    color: var(--primary-color);
}

h2 {
    font-size: 1.75rem;
    margin-bottom: 24px;
    color: var(--text-color);
}

h3 {
    font-size: 1.25rem;
    margin-bottom: 16px;
    color: var(--text-color);
}

h4 {
    font-size: 1.1rem;
    margin-bottom: 12px;
    color: var(--text-muted);
}

.subtitle {
    font-size: 1.1rem;
    color: var(--text-muted);
    margin-bottom: 32px;
}

.view {
    animation: fadeIn 0.3s ease-in;
}

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

.hidden {
    display: none !important;
}

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

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

.form-group input {
    width: 100%;
    padding: 12px;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    font-size: 1rem;
    transition: border-color 0.2s;
}

.form-group input:focus {
    outline: none;
    border-color: var(--primary-color);
}

.form-row {
    display: grid;
    grid-template-columns: 1fr 1fr auto;
    gap: 16px;
    align-items: end;
}

.btn {
    padding: 12px 24px;
    border: none;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s;
    margin-right: 8px;
    touch-action: manipulation;
    -webkit-tap-highlight-color: transparent;
}

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

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

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

.btn-secondary:hover {
    background-color: #4b5563;
    transform: translateY(-1px);
    box-shadow: var(--shadow);
}

.header-bar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 32px;
    flex-wrap: wrap;
    gap: 16px;
}

.header-bar > div {
    display: flex;
    align-items: center;
    gap: 12px;
    flex-wrap: wrap;
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 20px;
    margin-bottom: 40px;
}

.stat-card {
    background-color: var(--bg-color);
    padding: 24px;
    border-radius: 12px;
    border: 2px solid var(--border-color);
    transition: transform 0.2s, box-shadow 0.2s;
}

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

.stat-label {
    font-size: 0.875rem;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.5px;
    margin-bottom: 8px;
}

.stat-value {
    font-size: 2rem;
    font-weight: bold;
    color: var(--text-color);
}

#statusCard.on-track {
    border-color: var(--success-color);
    background-color: #ecfdf5;
}

#statusCard.on-track .stat-value {
    color: var(--success-color);
}

#statusCard.behind {
    border-color: var(--danger-color);
    background-color: #fef2f2;
}

#statusCard.behind .stat-value {
    color: var(--danger-color);
}

#statusCard.ahead {
    border-color: var(--primary-color);
    background-color: #eef2ff;
}

#statusCard.ahead .stat-value {
    color: var(--primary-color);
}

.chart-container {
    background-color: var(--card-bg);
    padding: 24px;
    border-radius: 12px;
    border: 2px solid var(--border-color);
    margin-bottom: 40px;
    position: relative;
    overflow-x: auto;
    min-height: 400px;
}

.chart-container canvas {
    max-width: 100%;
    height: auto !important;
    min-height: 350px !important;
}

.daily-progress {
    background-color: var(--bg-color);
    padding: 24px;
    border-radius: 12px;
    border: 2px solid var(--border-color);
}

.progress-list {
    margin-top: 24px;
    max-height: 300px;
    overflow-y: auto;
}

.progress-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 12px;
    background-color: var(--card-bg);
    border-radius: 8px;
    margin-bottom: 8px;
    border: 1px solid var(--border-color);
}

.progress-item-date {
    font-weight: 500;
}

.progress-item-tasks {
    color: var(--primary-color);
    font-weight: 600;
}

.progress-item-actions {
    display: flex;
    gap: 8px;
}

.btn-small {
    padding: 6px 12px;
    font-size: 0.875rem;
    margin: 0;
}

.message {
    position: fixed;
    top: 20px;
    right: 20px;
    padding: 16px 24px;
    border-radius: 8px;
    box-shadow: var(--shadow-lg);
    animation: slideIn 0.3s ease-out;
    z-index: 1000;
    max-width: 400px;
}

@keyframes slideIn {
    from {
        transform: translateX(400px);
        opacity: 0;
    }
    to {
        transform: translateX(0);
        opacity: 1;
    }
}

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

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

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

@media (max-width: 768px) {
    body {
        padding: 10px;
    }
    
    .container {
        padding: 20px;
        border-radius: 8px;
    }
    
    h1 {
        font-size: 1.75rem;
    }
    
    h2 {
        font-size: 1.5rem;
    }
    
    .subtitle {
        font-size: 1rem;
    }
    
    .form-row {
        grid-template-columns: 1fr;
    }
    
    .stats-grid {
        grid-template-columns: 1fr;
        gap: 12px;
    }
    
    .stat-card {
        padding: 16px;
    }
    
    .stat-value {
        font-size: 1.5rem;
    }
    
    .header-bar {
        flex-direction: column;
        gap: 12px;
        align-items: stretch;
    }
    
    .header-bar .btn {
        width: 100%;
        margin-right: 0;
        margin-bottom: 8px;
    }
    
    .chart-container {
        padding: 16px;
        margin-bottom: 20px;
        overflow-x: auto;
        -webkit-overflow-scrolling: touch;
        min-height: 350px;
    }
    
    .chart-container canvas {
        min-height: 300px !important;
    }
    
    .daily-progress {
        padding: 16px;
    }
    
    .form-group input,
    .btn {
        font-size: 16px; /* Prevents zoom on iOS */
    }
    
    .btn {
        padding: 14px 20px;
        min-height: 44px; /* Touch-friendly size */
    }
    
    .btn-small {
        padding: 8px 14px;
        min-height: 36px;
    }
    
    .progress-item {
        flex-wrap: wrap;
        gap: 8px;
    }
    
    .progress-item-actions {
        width: 100%;
        justify-content: flex-end;
    }
    
    .message {
        top: 10px;
        right: 10px;
        left: 10px;
        max-width: none;
    }
}

@media (max-width: 480px) {
    h1 {
        font-size: 1.5rem;
    }
    
    .stat-value {
        font-size: 1.25rem;
    }
    
    .chart-container {
        padding: 12px;
        min-height: 320px;
    }
    
    .chart-container canvas {
        min-height: 280px !important;
    }
}