:root {
    --primary-color: #3b82f6;
    --primary-dark: #2563eb;
    --secondary-color: #10b981;
    --danger-color: #ef4444;
    --warning-color: #f59e0b;
    --info-color: #06b6d4;
    --success-color: #22c55e;
    --dark-bg: #111827;
    --card-bg: #1f2937;
    --border-color: #374151;
    --text-primary: #f9fafb;
    --text-secondary: #9ca3af;
    --text-muted: #6b7280;
}

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

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background: var(--dark-bg);
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

.container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 0 20px;
}

/* Header */
.header {
    background: var(--card-bg);
    border-bottom: 1px solid var(--border-color);
    position: sticky;
    top: 0;
    z-index: 100;
}

.header-content {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 1rem 0;
}

.logo {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--primary-color);
}

.nav {
    display: flex;
    gap: 2rem;
}

.nav-link {
    color: var(--text-secondary);
    text-decoration: none;
    font-weight: 500;
    transition: color 0.2s;
    position: relative;
}

.nav-link:hover,
.nav-link.active {
    color: var(--text-primary);
}

.nav-link.active::after {
    content: '';
    position: absolute;
    bottom: -1rem;
    left: 0;
    right: 0;
    height: 2px;
    background: var(--primary-color);
}

.built-with {
    color: var(--text-muted);
    text-decoration: none;
    font-size: 0.875rem;
    transition: color 0.2s;
}

.built-with:hover {
    color: var(--primary-color);
}

/* Main Content */
.main {
    flex: 1;
    padding: 2rem 0;
}

.section {
    display: none;
}

.section.active {
    display: block;
}

.page-title {
    font-size: 2rem;
    font-weight: 700;
    margin-bottom: 2rem;
}

/* Stats Grid */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1.5rem;
    margin-bottom: 2rem;
}

.stat-card {
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 0.75rem;
    padding: 1.5rem;
    display: flex;
    align-items: center;
    gap: 1rem;
    transition: transform 0.2s, box-shadow 0.2s;
}

.stat-card:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.3);
}

.stat-icon {
    width: 48px;
    height: 48px;
    background: var(--primary-color);
    border-radius: 0.5rem;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
}

.stat-content h3 {
    font-size: 0.875rem;
    color: var(--text-secondary);
    margin-bottom: 0.25rem;
}

.stat-value {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 0.25rem;
}

.stat-change {
    font-size: 0.75rem;
    font-weight: 500;
}

.stat-change.positive {
    color: var(--success-color);
}

.stat-change.negative {
    color: var(--danger-color);
}

.stat-change.neutral {
    color: var(--text-muted);
}

/* Charts */
.charts-container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(400px, 1fr));
    gap: 1.5rem;
    margin-bottom: 2rem;
}

.chart-card {
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 0.75rem;
    padding: 1.5rem;
}

.chart-card h3 {
    margin-bottom: 1rem;
    font-size: 1.125rem;
}

.chart-placeholder {
    height: 200px;
    background: var(--dark-bg);
    border-radius: 0.5rem;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--text-muted);
}

/* Alerts */
.alerts-section {
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 0.75rem;
    padding: 1.5rem;
}

.alerts-section h3 {
    margin-bottom: 1rem;
    font-size: 1.125rem;
}

.alert-list {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.alert-item {
    display: flex;
    align-items: flex-start;
    gap: 0.75rem;
    padding: 0.75rem;
    background: var(--dark-bg);
    border-radius: 0.5rem;
    border-left: 3px solid;
}

.alert-item.info {
    border-left-color: var(--info-color);
}

.alert-item.success {
    border-left-color: var(--success-color);
}

.alert-item.warning {
    border-left-color: var(--warning-color);
}

.alert-icon {
    width: 32px;
    height: 32px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
}

.alert-item.info .alert-icon {
    background: rgba(6, 182, 212, 0.1);
    color: var(--info-color);
}

.alert-item.success .alert-icon {
    background: rgba(34, 197, 94, 0.1);
    color: var(--success-color);
}

.alert-item.warning .alert-icon {
    background: rgba(245, 158, 11, 0.1);
    color: var(--warning-color);
}

.alert-content p {
    margin-bottom: 0.25rem;
    font-size: 0.875rem;
}

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

/* Devices */
.device-filters {
    display: flex;
    gap: 1rem;
    margin-bottom: 1.5rem;
    flex-wrap: wrap;
}

.search-input,
.filter-select {
    padding: 0.5rem 1rem;
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 0.5rem;
    color: var(--text-primary);
    font-size: 0.875rem;
}

.search-input {
    flex: 1;
    min-width: 200px;
}

.filter-select {
    min-width: 150px;
}

.devices-table-container {
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 0.75rem;
    overflow: hidden;
}

.devices-table {
    width: 100%;
    border-collapse: collapse;
}

.devices-table th {
    background: var(--dark-bg);
    padding: 1rem;
    text-align: left;
    font-weight: 600;
    font-size: 0.875rem;
    color: var(--text-secondary);
    border-bottom: 1px solid var(--border-color);
}

.devices-table td {
    padding: 1rem;
    border-bottom: 1px solid var(--border-color);
    font-size: 0.875rem;
}

.devices-table tr:last-child td {
    border-bottom: none;
}

.device-info {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.status-badge {
    padding: 0.25rem 0.75rem;
    border-radius: 9999px;
    font-size: 0.75rem;
    font-weight: 500;
}

.status-badge.online {
    background: rgba(34, 197, 94, 0.1);
    color: var(--success-color);
}

.status-badge.offline {
    background: rgba(239, 68, 68, 0.1);
    color: var(--danger-color);
}

.btn-icon {
    background: none;
    border: none;
    color: var(--text-secondary);
    cursor: pointer;
    padding: 0.25rem;
    border-radius: 0.25rem;
    transition: color 0.2s, background 0.2s;
}

.btn-icon:hover {
    color: var(--text-primary);
    background: var(--dark-bg);
}

/* Tools */
.tools-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 1.5rem;
}

.tool-card {
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 0.75rem;
    padding: 1.5rem;
    transition: transform 0.2s, box-shadow 0.2s;
}

.tool-card:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.3);
}

.tool-icon {
    width: 64px;
    height: 64px;
    background: var(--primary-color);
    border-radius: 0.75rem;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    margin-bottom: 1rem;
}

.tool-card h3 {
    font-size: 1.25rem;
    margin-bottom: 0.5rem;
}

.tool-card p {
    color: var(--text-secondary);
    font-size: 0.875rem;
    margin-bottom: 1.5rem;
}

.tool-form {
    display: flex;
    gap: 0.5rem;
    margin-bottom: 1rem;
}

.tool-form input {
    flex: 1;
    padding: 0.5rem 1rem;
    background: var(--dark-bg);
    border: 1px solid var(--border-color);
    border-radius: 0.5rem;
    color: var(--text-primary);
    font-size: 0.875rem;
}

.tool-result {
    padding: 0.75rem;
    background: var(--dark-bg);
    border-radius: 0.5rem;
    font-size: 0.875rem;
    color: var(--text-secondary);
    min-height: 60px;
    display: flex;
    align-items: center;
    justify-content: center;
}

/* Settings */
.settings-container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: 1.5rem;
}

.settings-card {
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 0.75rem;
    padding: 1.5rem;
}

.settings-card h3 {
    margin-bottom: 1.5rem;
    font-size: 1.125rem;
}

.form-group {
    margin-bottom: 1.25rem;
}

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--text-secondary);
}

.form-input {
    width: 100%;
    padding: 0.5rem 1rem;
    background: var(--dark-bg);
    border: 1px solid var(--border-color);
    border-radius: 0.5rem;
    color: var(--text-primary);
    font-size: 0.875rem;
    transition: border-color 0.2s;
}

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

.checkbox-label {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    cursor: pointer;
}

.checkbox-label input[type="checkbox"] {
    width: 18px;
    height: 18px;
    accent-color: var(--primary-color);
}

/* Buttons */
.btn {
    padding: 0.5rem 1.25rem;
    border: none;
    border-radius: 0.5rem;
    font-size: 0.875rem;
    font-weight: 500;
    cursor: pointer;
    transition: background-color 0.2s, transform 0.1s;
}

.btn:active {
    transform: scale(0.98);
}

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

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

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

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

/* Footer */
.footer {
    background: var(--card-bg);
    border-top: 1px solid var(--border-color);
    padding: 1.5rem 0;
    text-align: center;
    color: var(--text-muted);
    font-size: 0.875rem;
    margin-top: auto;
}

/* Responsive */
@media (max-width: 768px) {
    .header-content {
        flex-direction: column;
        gap: 1rem;
    }

    .nav {
        gap: 1rem;
    }

    .stats-grid {
        grid-template-columns: 1fr;
    }

    .charts-container {
        grid-template-columns: 1fr;
    }

    .device-filters {
        flex-direction: column;
    }

    .search-input {
        min-width: 100%;
    }

    .tools-grid {
        grid-template-columns: 1fr;
    }

    .settings-container {
        grid-template-columns: 1fr;
    }

    .devices-table-container {
        overflow-x: auto;
    }
}

/* Loading animation */
@keyframes pulse {
    0%, 100% {
        opacity: 1;
    }
    50% {
        opacity: 0.5;
    }
}

.loading {
    animation: pulse 2s cubic-bezier(0.4, 0, 0.6, 1) infinite;
}

/* Progress bar */
.progress-bar {
    width: 100%;
    height: 8px;
    background: var(--dark-bg);
    border-radius: 9999px;
    overflow: hidden;
    margin: 0.5rem 0;
}

.progress-fill {
    height: 100%;
    background: var(--primary-color);
    border-radius: 9999px;
    transition: width 0.3s ease;
}