:root {
    --primary-color: #2563eb;
    --secondary-color: #64748b;
    --success-color: #10b981;
    --warning-color: #f59e0b;
    --danger-color: #ef4444;
    --bg-color: #f8fafc;
    --card-bg: #ffffff;
    --text-primary: #1e293b;
    --text-secondary: #64748b;
    --border-color: #e2e8f0;
    --in-range-color: #10b981;
    --low-color: #ef4444;
    --high-color: #f59e0b;
    --very-low-color: #dc2626;
    --very-high-color: #b91c1c;
}

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

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

.header {
    background: var(--card-bg);
    padding: 1rem 2rem;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.header h1 {
    font-size: 1.5rem;
    font-weight: 600;
}

.connection-status {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 0.875rem;
}

.status-dot {
    width: 8px;
    height: 8px;
    border-radius: 50%;
    background: var(--warning-color);
    animation: pulse 2s infinite;
}

.status-dot.connected {
    background: var(--success-color);
    animation: none;
}

.status-dot.error {
    background: var(--danger-color);
    animation: none;
}

@keyframes pulse {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.5; }
}

#app {
    max-width: 1200px;
    margin: 0 auto;
}

.stats-bar {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1rem;
    padding: 2rem;
}

.stat-card {
    background: var(--card-bg);
    border-radius: 8px;
    padding: 1.5rem;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
    text-align: center;
}

.stat-card.current-bg {
    border-left: 4px solid var(--primary-color);
}

.stat-value {
    font-size: 2rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
}

.unit {
    font-size: 1rem;
    font-weight: 400;
    color: var(--text-secondary);
}

.trend-arrow {
    font-size: 1.5rem;
}

.stat-label {
    font-size: 0.875rem;
    color: var(--text-secondary);
    font-weight: 500;
}

.stat-detail, .last-update {
    font-size: 0.75rem;
    color: var(--text-secondary);
    margin-top: 0.25rem;
}

.chart-container {
    background: var(--card-bg);
    margin: 0 2rem 2rem;
    padding: 2rem;
    border-radius: 8px;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
    height: 400px;
}

.controls {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin: 0 2rem 2rem;
    gap: 1rem;
}

.time-controls {
    display: flex;
    gap: 0.5rem;
}

.time-btn {
    padding: 0.5rem 1rem;
    border: 1px solid var(--border-color);
    background: var(--card-bg);
    border-radius: 6px;
    cursor: pointer;
    font-size: 0.875rem;
    transition: all 0.2s;
}

.time-btn:hover {
    background: var(--bg-color);
}

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

.action-controls {
    display: flex;
    gap: 0.5rem;
}

.action-btn {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.5rem 1rem;
    background: var(--primary-color);
    color: white;
    border: none;
    border-radius: 6px;
    cursor: pointer;
    font-size: 0.875rem;
    transition: background-color 0.2s;
}

.action-btn:hover {
    background: #1d4ed8;
}

.btn-icon {
    font-size: 1rem;
}

.summary-section, .events-section {
    background: var(--card-bg);
    margin: 0 2rem 2rem;
    padding: 2rem;
    border-radius: 8px;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
}

.summary-section h3, .events-section h3 {
    margin-bottom: 1rem;
    font-size: 1.125rem;
    font-weight: 600;
}

.summary-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1rem;
}

.summary-item {
    display: flex;
    justify-content: space-between;
    padding: 0.5rem 0;
    border-bottom: 1px solid var(--border-color);
}

.summary-label {
    color: var(--text-secondary);
    font-size: 0.875rem;
}

.events-list {
    min-height: 100px;
    margin-bottom: 1rem;
}

.event-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0.75rem 0;
    border-bottom: 1px solid var(--border-color);
}

.event-info {
    display: flex;
    flex-direction: column;
    gap: 0.25rem;
}

.event-type {
    font-weight: 500;
    text-transform: capitalize;
}

.event-details {
    font-size: 0.875rem;
    color: var(--text-secondary);
}

.event-time {
    font-size: 0.75rem;
    color: var(--text-secondary);
}

.no-events {
    color: var(--text-secondary);
    font-style: italic;
    text-align: center;
    padding: 2rem;
}

.add-event {
    text-align: center;
}

/* Modal Styles */
.modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.5);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
}

.modal.hidden {
    display: none;
}

.modal-content {
    background: var(--card-bg);
    border-radius: 8px;
    width: 90%;
    max-width: 500px;
    max-height: 90vh;
    overflow-y: auto;
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1.5rem;
    border-bottom: 1px solid var(--border-color);
}

.modal-header h3 {
    margin: 0;
    font-size: 1.125rem;
    font-weight: 600;
}

.close-btn {
    background: none;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    color: var(--text-secondary);
    padding: 0;
    width: 2rem;
    height: 2rem;
    display: flex;
    align-items: center;
    justify-content: center;
}

.close-btn:hover {
    color: var(--text-primary);
}

.modal-body {
    padding: 1.5rem;
}

.form-group {
    margin-bottom: 1rem;
}

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 500;
    color: var(--text-primary);
}

.form-group input,
.form-group select,
.form-group textarea {
    width: 100%;
    padding: 0.5rem;
    border: 1px solid var(--border-color);
    border-radius: 4px;
    font-size: 0.875rem;
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

.form-actions {
    display: flex;
    gap: 1rem;
    justify-content: flex-end;
    margin-top: 1.5rem;
}

.btn-primary {
    background: var(--primary-color);
    color: white;
    border: none;
    padding: 0.5rem 1rem;
    border-radius: 6px;
    cursor: pointer;
    font-size: 0.875rem;
}

.btn-primary:hover {
    background: #1d4ed8;
}

.btn-secondary {
    background: var(--card-bg);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
    padding: 0.5rem 1rem;
    border-radius: 6px;
    cursor: pointer;
    font-size: 0.875rem;
}

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

/* Glucose value colors */
.glucose-low { color: var(--low-color); }
.glucose-high { color: var(--high-color); }
.glucose-very-low { color: var(--very-low-color); }
.glucose-very-high { color: var(--very-high-color); }
.glucose-in-range { color: var(--in-range-color); }

/* Responsive Design */
@media (max-width: 768px) {
    .header {
        padding: 1rem;
    }
    
    .stats-bar {
        grid-template-columns: 1fr;
        padding: 1rem;
    }
    
    .controls {
        flex-direction: column;
        align-items: stretch;
        margin: 0 1rem 1rem;
    }
    
    .time-controls {
        justify-content: center;
    }
    
    .action-controls {
        justify-content: center;
    }
    
    .summary-section, .events-section {
        margin: 0 1rem 1rem;
        padding: 1rem;
    }
    
    .chart-container {
        margin: 0 1rem 1rem;
        padding: 1rem;
        height: 300px;
    }
    
    .summary-grid {
        grid-template-columns: 1fr;
    }
}