/* Apple-inspired Design System */
:root {
    --system-background: #f2f2f7;
    --secondary-system-background: #ffffff;
    --tertiary-system-background: #f2f2f7;
    --system-grouped-background: #f2f2f7;
    --secondary-system-grouped-background: #ffffff;

    --label-primary: #000000;
    --label-secondary: #3c3c4399;
    --label-tertiary: #3c3c434c;
    --label-quaternary: #3c3c432e;

    --separator: #c6c6c8;

    --blue: #007aff;
    --green: #34c759;
    --orange: #ff9500;
    --red: #ff3b30;
    --purple: #af52de;
    --teal: #5ac8fa;

    --shadow-light: 0 1px 3px rgba(0, 0, 0, 0.12), 0 1px 2px rgba(0, 0, 0, 0.24);
    --shadow-medium: 0 3px 6px rgba(0, 0, 0, 0.15), 0 2px 4px rgba(0, 0, 0, 0.12);
    --shadow-heavy: 0 10px 20px rgba(0, 0, 0, 0.15), 0 3px 6px rgba(0, 0, 0, 0.10);

    --border-radius: 12px;
    --border-radius-large: 16px;

    --spacing-xs: 4px;
    --spacing-sm: 8px;
    --spacing-md: 16px;
    --spacing-lg: 20px;
    --spacing-xl: 24px;
    --spacing-2xl: 32px;
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'SF Pro Display', 'SF Pro Text', 'Helvetica Neue', Helvetica, Arial, sans-serif;
    background-color: var(--system-background);
    color: var(--label-primary);
    line-height: 1.4;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* App Container */
.app-container {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* Header */
.app-header {
    background-color: var(--secondary-system-background);
    border-bottom: 1px solid var(--separator);
    padding: var(--spacing-lg) var(--spacing-xl);
}

.header-content {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    max-width: 1200px;
    margin: 0 auto;
}

.header-icon {
    width: 40px;
    height: 40px;
    background: linear-gradient(135deg, var(--blue), var(--purple));
    border-radius: var(--border-radius);
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 18px;
}

.header-text h1 {
    font-size: 28px;
    font-weight: 700;
    color: var(--label-primary);
    margin-bottom: 2px;
}

.header-text p {
    font-size: 14px;
    color: var(--label-secondary);
    font-weight: 400;
}

/* Main Content */
.main-content {
    flex: 1;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-xl);
    width: 100%;
}

/* Section Headers */
.section-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: var(--spacing-lg);
    padding: var(--spacing-xl) 0 var(--spacing-md) 0;
}

.section-header h2 {
    font-size: 22px;
    font-weight: 600;
    color: var(--label-primary);
}

.last-updated, .chart-period {
    font-size: 13px;
    color: var(--label-secondary);
    font-weight: 400;
}

/* Stats Grid */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-2xl);
}

/* Stat Cards */
.stat-card {
    background-color: var(--secondary-system-background);
    border-radius: var(--border-radius-large);
    padding: var(--spacing-xl);
    box-shadow: var(--shadow-light);
    border: 1px solid var(--separator);
    transition: all 0.2s ease;
    display: flex;
    align-items: center;
    gap: var(--spacing-lg);
}

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

.today-card {
    background: linear-gradient(135deg, var(--blue), var(--purple));
    color: white;
}

.today-card .stat-value,
.today-card .stat-label,
.today-card .stat-subtitle {
    color: white;
}

.card-icon {
    width: 48px;
    height: 48px;
    border-radius: var(--border-radius);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 20px;
    flex-shrink: 0;
}

.stat-card:not(.today-card) .card-icon {
    background-color: var(--tertiary-system-background);
    color: var(--blue);
}

.today-card .card-icon {
    background-color: rgba(255, 255, 255, 0.2);
    color: white;
}

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

.stat-value {
    font-size: 28px;
    font-weight: 700;
    color: var(--label-primary);
    margin-bottom: var(--spacing-xs);
    font-variant-numeric: tabular-nums;
}

.stat-label {
    font-size: 15px;
    font-weight: 600;
    color: var(--label-primary);
    margin-bottom: 2px;
}

.stat-subtitle {
    font-size: 13px;
    color: var(--label-secondary);
    font-weight: 400;
}

/* Device Section */
.device-section {
    margin-bottom: var(--spacing-2xl);
}

.device-card {
    background-color: var(--secondary-system-background);
    border-radius: var(--border-radius-large);
    padding: var(--spacing-xl);
    box-shadow: var(--shadow-light);
    border: 1px solid var(--separator);
}

.device-info {
    display: flex;
    align-items: center;
    gap: var(--spacing-lg);
}

.device-icon {
    width: 48px;
    height: 48px;
    background-color: var(--tertiary-system-background);
    border-radius: var(--border-radius);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--green);
    font-size: 20px;
}

.device-details {
    flex: 1;
}

.device-name {
    font-size: 17px;
    font-weight: 600;
    color: var(--label-primary);
    margin-bottom: 2px;
}

.device-model {
    font-size: 14px;
    color: var(--label-secondary);
    font-weight: 400;
}

/* Chart Section */
.chart-section {
    margin-bottom: var(--spacing-2xl);
}

.chart-container {
    background-color: var(--secondary-system-background);
    border-radius: var(--border-radius-large);
    padding: var(--spacing-xl);
    box-shadow: var(--shadow-light);
    border: 1px solid var(--separator);
    position: relative;
    height: 400px;
}

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

/* Activity Section */
.activity-section {
    margin-bottom: var(--spacing-2xl);
}

.activity-list {
    background-color: var(--secondary-system-background);
    border-radius: var(--border-radius-large);
    overflow: hidden;
    box-shadow: var(--shadow-light);
    border: 1px solid var(--separator);
}

.activity-item {
    padding: var(--spacing-lg);
    border-bottom: 1px solid var(--separator);
    display: flex;
    justify-content: space-between;
    align-items: center;
    transition: background-color 0.2s ease;
}

.activity-item:hover {
    background-color: var(--tertiary-system-background);
}

.activity-item:last-child {
    border-bottom: none;
}

.activity-item .device-info {
    flex: 1;
}

.activity-item .device-name {
    font-size: 15px;
    font-weight: 600;
    color: var(--label-primary);
    margin-bottom: 2px;
}

.activity-item .timestamp {
    font-size: 13px;
    color: var(--label-secondary);
}

.activity-stats {
    text-align: right;
    display: flex;
    flex-direction: column;
    gap: 2px;
}

.activity-stats div {
    font-size: 12px;
    color: var(--label-tertiary);
    font-variant-numeric: tabular-nums;
}

/* Loading State */
.loading-state {
    padding: var(--spacing-2xl);
    text-align: center;
    color: var(--label-secondary);
}

.loading-state i {
    font-size: 24px;
    margin-bottom: var(--spacing-md);
    display: block;
}

.loading-state p {
    font-size: 15px;
}

/* Footer */
.app-footer {
    background-color: var(--secondary-system-background);
    border-top: 1px solid var(--separator);
    padding: var(--spacing-lg) var(--spacing-xl);
    display: flex;
    justify-content: space-between;
    align-items: center;
    max-width: 1200px;
    margin: 0 auto;
    width: 100%;
}

.refresh-button {
    background-color: var(--blue);
    color: white;
    border: none;
    padding: var(--spacing-sm) var(--spacing-lg);
    border-radius: var(--border-radius);
    font-size: 14px;
    font-weight: 600;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    transition: all 0.2s ease;
}

.refresh-button:hover {
    background-color: #0056cc;
    transform: scale(1.02);
}

.refresh-button:active {
    transform: scale(0.98);
}

.sync-status {
    font-size: 13px;
    color: var(--label-secondary);
    font-weight: 400;
}

/* Status Messages */
.success, .error {
    background-color: var(--green);
    color: white;
    padding: var(--spacing-md) var(--spacing-lg);
    border-radius: var(--border-radius);
    margin-bottom: var(--spacing-lg);
    font-size: 14px;
    font-weight: 500;
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

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

/* Responsive Design */
@media (max-width: 768px) {
    .app-header,
    .app-footer {
        padding-left: var(--spacing-lg);
        padding-right: var(--spacing-lg);
    }

    .main-content {
        padding-left: var(--spacing-lg);
        padding-right: var(--spacing-lg);
    }

    .section-header {
        padding-top: var(--spacing-lg);
    }

    .stats-grid {
        grid-template-columns: 1fr;
        gap: var(--spacing-md);
    }

    .stat-card {
        padding: var(--spacing-lg);
    }

    .header-content {
        gap: var(--spacing-sm);
    }

    .header-text h1 {
        font-size: 24px;
    }

    .section-header h2 {
        font-size: 20px;
    }

    .chart-container {
        height: 300px;
        padding: var(--spacing-lg);
    }

    .app-footer {
        flex-direction: column;
        gap: var(--spacing-md);
        align-items: stretch;
    }

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

@media (max-width: 480px) {
    .stat-card {
        flex-direction: column;
        text-align: center;
        gap: var(--spacing-md);
    }

    .card-content {
        text-align: center;
    }

    .device-info {
        flex-direction: column;
        text-align: center;
        gap: var(--spacing-md);
    }

    .activity-item {
        flex-direction: column;
        align-items: flex-start;
        gap: var(--spacing-sm);
    }

    .activity-stats {
        text-align: left;
        width: 100%;
    }
}