:root {
    --bg-color: #f8fafc;
    --surface-color: #ffffff;
    --surface-border: #e2e8f0;
    --text-primary: #0f172a;
    --text-secondary: #64748b;
    --primary: #0f172a;
    --primary-hover: #1e293b;
    --success: #10b981;
    --danger: #ef4444;
    --radius: 0.5rem;
    --radius-lg: 0.75rem;
}

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

body {
    font-family: 'Inter', -apple-system, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-primary);
    line-height: 1.5;
    -webkit-font-smoothing: antialiased;
}

.app-container {
    display: flex;
    height: 100vh;
}

/* Sidebar */
.sidebar {
    width: 250px;
    background: var(--surface-color);
    border-right: 1px solid var(--surface-border);
    display: flex;
    flex-direction: column;
}

.sidebar-header {
    padding: 1.5rem;
    border-bottom: 1px solid var(--surface-border);
}

.sidebar-header h2 {
    font-size: 1.25rem;
    font-weight: 600;
}

.sidebar-nav {
    padding: 1rem;
    display: flex;
    flex-direction: column;
    gap: 0.25rem;
}

.nav-item {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 0.75rem 1rem;
    border: none;
    background: transparent;
    color: var(--text-secondary);
    font-size: 0.875rem;
    font-weight: 500;
    border-radius: var(--radius);
    cursor: pointer;
    text-align: left;
    transition: all 0.2s;
}

.nav-item:hover {
    background: #f1f5f9;
    color: var(--text-primary);
}

.nav-item.active {
    background: #f1f5f9;
    color: var(--text-primary);
    font-weight: 600;
}

/* Main Content */
.main-content {
    flex: 1;
    display: flex;
    flex-direction: column;
    overflow: hidden;
}

.top-header {
    height: 64px;
    background: var(--surface-color);
    border-bottom: 1px solid var(--surface-border);
    display: flex;
    align-items: center;
    padding: 0 2rem;
    justify-content: flex-end;
}

.status-indicator {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--text-secondary);
}

.status-dot {
    width: 8px;
    height: 8px;
    border-radius: 50%;
    background: var(--danger);
    transition: background-color 0.3s;
}
.status-dot.connected { background: var(--success); }

.content-area {
    padding: 2rem;
    overflow-y: auto;
    flex: 1;
}

.tab-pane {
    display: none;
}
.tab-pane.active {
    display: block;
}

/* Components */
.card {
    background: var(--surface-color);
    border: 1px solid var(--surface-border);
    border-radius: var(--radius-lg);
    padding: 1.5rem;
    box-shadow: 0 1px 2px 0 rgba(0,0,0,0.05);
}

.card h3 {
    margin-bottom: 0.5rem;
    font-size: 1.125rem;
}

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

.mt-2 { margin-top: 1.5rem; }

/* Forms */
.form-layout {
    display: flex;
    flex-direction: column;
    gap: 1rem;
    max-width: 400px;
}

.form-group {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.form-group label {
    font-size: 0.875rem;
    font-weight: 500;
}

.form-group input {
    padding: 0.5rem 0.75rem;
    border: 1px solid var(--surface-border);
    border-radius: var(--radius);
    font-family: inherit;
    font-size: 0.875rem;
    outline: none;
    transition: border-color 0.2s, box-shadow 0.2s;
}

.form-group input:focus {
    border-color: var(--primary);
    box-shadow: 0 0 0 1px var(--primary);
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.5rem 1rem;
    font-size: 0.875rem;
    font-weight: 500;
    border-radius: var(--radius);
    cursor: pointer;
    transition: all 0.2s;
    border: 1px solid transparent;
}

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

.btn-outline {
    background: transparent;
    border-color: var(--surface-border);
    color: var(--text-primary);
}
.btn-outline:hover {
    background: #f1f5f9;
}

/* Products Grid */
.action-bar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1.5rem;
}

.products-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 1.5rem;
}

.product-card {
    background: var(--surface-color);
    border: 1px solid var(--surface-border);
    border-radius: var(--radius-lg);
    padding: 1.5rem;
    display: flex;
    flex-direction: column;
    gap: 1rem;
    transition: transform 0.2s, box-shadow 0.2s;
}
.product-card:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 6px -1px rgba(0,0,0,0.1), 0 2px 4px -1px rgba(0,0,0,0.06);
}

.product-header h4 {
    font-size: 1.125rem;
    margin-bottom: 0.25rem;
}
.product-price {
    font-weight: 600;
    color: var(--success);
}
.product-id {
    font-size: 0.75rem;
    color: var(--text-secondary);
    font-family: monospace;
}

/* Modal */
.modal {
    position: fixed;
    top: 0; left: 0; right: 0; bottom: 0;
    background: rgba(15, 23, 42, 0.4);
    backdrop-filter: blur(4px);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 50;
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.2s;
}

.modal:not(.hidden) {
    opacity: 1;
    pointer-events: auto;
}

.modal-content {
    background: var(--surface-color);
    border-radius: var(--radius-lg);
    padding: 2rem;
    width: 100%;
    max-width: 450px;
    box-shadow: 0 20px 25px -5px rgba(0,0,0,0.1);
    transform: translateY(20px);
    transition: transform 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}
.modal:not(.hidden) .modal-content {
    transform: translateY(0);
}

.form-actions {
    display: flex;
    justify-content: flex-end;
    gap: 0.75rem;
    margin-top: 1rem;
}

.hidden { display: none !important; }

/* Animations */
@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}
.fade-in { animation: fadeIn 0.4s ease-out forwards; }