:root {
    /* Colors */
    --primary: #2563eb;
    --primary-hover: #1d4ed8;
    --secondary: #64748b;
    --success: #10b981;
    --danger: #ef4444;
    --warning: #f59e0b;
    --background: #f8fafc;
    --surface: #ffffff;
    --border: #e2e8f0;
    --text-main: #1e293b;
    --text-muted: #64748b;
    --sidebar-bg: #1e293b;
    --sidebar-text: #f1f5f9;
    --sidebar-hover: #334155;

    /* Spacing */
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;

    /* Radius */
    --radius-sm: 0.25rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;

    /* Shadows */
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1);
}

* {
    box-sizing: border-box;
}

body {
    margin: 0;
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    background-color: var(--background);
    color: var(--text-main);
    line-height: 1.5;
    height: 100vh;
    display: flex;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
    margin-top: 0;
    font-weight: 600;
    color: var(--text-main);
}

a {
    color: var(--primary);
    text-decoration: none;
    transition: color 0.2s;
}

a:hover {
    color: var(--primary-hover);
}

/* Layout */
.app-layout {
    display: flex;
    width: 100%;
    height: 100%;
}

.sidebar {
    width: 260px;
    background-color: var(--sidebar-bg);
    color: var(--sidebar-text);
    display: flex;
    flex-direction: column;
    padding: var(--spacing-md);
    flex-shrink: 0;
}

.sidebar .logo {
    font-size: 1.25rem;
    font-weight: 700;
    margin-bottom: var(--spacing-xl);
    padding: var(--spacing-sm);
    color: white;
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

.sidebar nav {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xs);
}

.sidebar a {
    color: var(--sidebar-text);
    padding: var(--spacing-sm) var(--spacing-md);
    border-radius: var(--radius-md);
    display: block;
    font-weight: 500;
}

.sidebar a:hover, .sidebar a.active {
    background-color: var(--sidebar-hover);
    color: white;
}

.sidebar .footer {
    margin-top: auto;
    border-top: 1px solid var(--sidebar-hover);
    padding-top: var(--spacing-md);
}

.main-content {
    flex: 1;
    display: flex;
    flex-direction: column;
    overflow: hidden;
}

.top-bar {
    background-color: var(--surface);
    border-bottom: 1px solid var(--border);
    padding: var(--spacing-md) var(--spacing-xl);
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 64px;
}

.content-area {
    flex: 1;
    padding: var(--spacing-xl);
    overflow-y: auto;
}

/* Components */
.card {
    background-color: var(--surface);
    border-radius: var(--radius-md);
    border: 1px solid var(--border);
    box-shadow: var(--shadow-sm);
    padding: var(--spacing-lg);
    margin-bottom: var(--spacing-lg);
}

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: var(--spacing-sm) var(--spacing-md);
    border-radius: var(--radius-md);
    font-weight: 500;
    cursor: pointer;
    border: none;
    transition: all 0.2s;
    font-size: 0.875rem;
    gap: var(--spacing-sm);
}

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

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

.btn-secondary {
    background-color: white;
    border: 1px solid var(--border);
    color: var(--text-main);
}

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

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

.btn-danger:hover {
    background-color: #dc2626;
}

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

.form-group {
    margin-bottom: var(--spacing-md);
}

.form-label {
    display: block;
    margin-bottom: var(--spacing-xs);
    font-weight: 500;
    font-size: 0.875rem;
    color: var(--text-main);
}

.form-control {
    width: 100%;
    padding: 0.625rem;
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    font-size: 0.875rem;
    transition: border-color 0.2s;
}

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

/* Tables */
.table-container {
    overflow-x: auto;
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
}

table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.875rem;
}

th {
    background-color: var(--background);
    text-align: left;
    padding: var(--spacing-md);
    font-weight: 600;
    color: var(--text-muted);
    border-bottom: 1px solid var(--border);
}

td {
    padding: var(--spacing-md);
    border-bottom: 1px solid var(--border);
    color: var(--text-main);
}

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

/* Badges */
.badge {
    display: inline-flex;
    align-items: center;
    padding: 0.125rem 0.5rem;
    border-radius: 9999px;
    font-size: 0.75rem;
    font-weight: 500;
}

.badge-success {
    background-color: #dcfce7;
    color: #166534;
}

.badge-warning {
    background-color: #fef3c7;
    color: #92400e;
}

.badge-danger {
    background-color: #fee2e2;
    color: #991b1b;
}

/* Login Page */
.login-page {
    display: flex;
    align-items: center;
    justify-content: center;
    height: 100vh;
    background-color: var(--background);
}

.login-card {
    width: 100%;
    max-width: 400px;
    background: white;
    padding: var(--spacing-xl);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-lg);
    border: 1px solid var(--border);
}

.login-header {
    text-align: center;
    margin-bottom: var(--spacing-xl);
}

.login-header h2 {
    font-size: 1.5rem;
    color: var(--text-main);
}

/* Alerts */
.alert {
    padding: var(--spacing-md);
    border-radius: var(--radius-md);
    margin-bottom: var(--spacing-md);
    font-size: 0.875rem;
}

.alert-success {
    background-color: #dcfce7;
    color: #166534;
    border: 1px solid #bbf7d0;
}

.alert-danger {
    background-color: #fee2e2;
    color: #991b1b;
    border: 1px solid #fecaca;
}

/* Utilities */
.flex { display: flex; }
.items-center { align-items: center; }
.justify-between { justify-content: space-between; }
.gap-2 { gap: 0.5rem; }
.gap-4 { gap: 1rem; }
.mb-4 { margin-bottom: 1rem; }
.text-sm { font-size: 0.875rem; }
.text-muted { color: var(--text-muted); }

/* Folder Tree */
.folder-tree {
    list-style: none;
    padding: 0;
    margin: 0;
}

.folder-tree-root {
    margin-bottom: var(--spacing-sm);
}

.folder-tree .folder-tree {
    padding-left: var(--spacing-lg);
}

.folder-item {
    margin: 0;
}

.folder-row {
    display: flex;
    align-items: center;
    padding: var(--spacing-xs) var(--spacing-sm);
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: background-color 0.15s ease;
    gap: var(--spacing-xs);
}

.folder-row:hover {
    background-color: var(--background);
}

.folder-row.active {
    background-color: rgba(37, 99, 235, 0.1);
}

.folder-row.active .folder-name {
    color: var(--primary);
    font-weight: 600;
}

.folder-row.active .folder-icon {
    color: var(--primary);
}

.folder-toggle {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 20px;
    height: 20px;
    padding: 0;
    border: none;
    background: transparent;
    cursor: pointer;
    color: var(--text-muted);
    border-radius: var(--radius-sm);
    transition: all 0.15s ease;
    flex-shrink: 0;
}

.folder-toggle:hover {
    background-color: var(--border);
    color: var(--text-main);
}

.folder-arrow {
    transition: transform 0.2s ease;
}

.folder-toggle[aria-expanded="true"] .folder-arrow {
    transform: rotate(90deg);
}

.folder-toggle-spacer {
    width: 20px;
    flex-shrink: 0;
}

.folder-icon {
    color: var(--warning);
    flex-shrink: 0;
}

.folder-name {
    flex: 1;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
    font-size: 0.875rem;
    color: var(--text-main);
}

.folder-name:hover {
    color: var(--primary);
}

.folder-children {
    display: none;
    overflow: hidden;
}

.folder-children.open {
    display: block;
    animation: slideDown 0.2s ease;
}

@keyframes slideDown {
    from {
        opacity: 0;
        transform: translateY(-4px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}