:root {
    /* Colors */
    --primary: #3B82F6;
    --primary-dark: #2563EB;
    --primary-light: #60A5FA;
    --secondary: #10B981;
    --secondary-dark: #059669;
    --danger: #EF4444;
    --danger-dark: #DC2626;
    --warning: #F59E0B;
    --success: #10B981;
    --info: #3B82F6;
    
    /* Grays */
    --gray-50: #F9FAFB;
    --gray-100: #F3F4F6;
    --gray-200: #E5E7EB;
    --gray-300: #D1D5DB;
    --gray-400: #9CA3AF;
    --gray-500: #6B7280;
    --gray-600: #4B5563;
    --gray-700: #374151;
    --gray-800: #1F2937;
    --gray-900: #111827;
    
    /* Layout */
    --sidebar-width: 260px;
    --header-height: 64px;
    --border-radius: 8px;
    --border-radius-sm: 6px;
    --border-radius-lg: 12px;
    
    /* Shadows */
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow: 0 1px 3px 0 rgba(0, 0, 0, 0.1), 0 1px 2px -1px rgba(0, 0, 0, 0.1);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -2px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -4px rgba(0, 0, 0, 0.1);
    
    /* Typography */
    --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    --font-mono: "SF Mono", Monaco, "Cascadia Code", "Roboto Mono", Consolas, monospace;
}

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

body {
    font-family: var(--font-sans);
    font-size: 14px;
    line-height: 1.5;
    color: var(--gray-900);
    background: var(--gray-50);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* Layout */
.app-container {
    display: flex;
    min-height: 100vh;
}

.sidebar {
    width: var(--sidebar-width);
    background: white;
    border-right: 1px solid var(--gray-200);
    display: flex;
    flex-direction: column;
    position: fixed;
    height: 100vh;
    z-index: 100;
}

.sidebar-header {
    height: var(--header-height);
    padding: 0 20px;
    display: flex;
    align-items: center;
    border-bottom: 1px solid var(--gray-200);
}

.sidebar-logo {
    font-size: 20px;
    font-weight: 700;
    color: var(--primary);
}

.sidebar-nav {
    flex: 1;
    overflow-y: auto;
    padding: 20px 0;
}

.nav-section {
    margin-bottom: 24px;
}

.nav-section-title {
    font-size: 11px;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    color: var(--gray-500);
    padding: 0 20px;
    margin-bottom: 8px;
}

.nav-item {
    display: flex;
    align-items: center;
    padding: 10px 20px;
    color: var(--gray-700);
    text-decoration: none;
    transition: all 0.15s;
    border-left: 3px solid transparent;
}

.nav-item:hover {
    background: var(--gray-50);
    color: var(--primary);
}

.nav-item.active {
    background: var(--primary-light) / 0.1;
    color: var(--primary);
    border-left-color: var(--primary);
    font-weight: 500;
}

.nav-icon {
    width: 20px;
    height: 20px;
    margin-right: 12px;
    opacity: 0.8;
}

.nav-item.active .nav-icon {
    opacity: 1;
}

.main-content {
    flex: 1;
    margin-left: var(--sidebar-width);
    display: flex;
    flex-direction: column;
}

.header {
    height: var(--header-height);
    background: white;
    border-bottom: 1px solid var(--gray-200);
    display: flex;
    align-items: center;
    padding: 0 32px;
    justify-content: space-between;
}

.header-left {
    display: flex;
    align-items: center;
    gap: 16px;
}

.header-title {
    font-size: 20px;
    font-weight: 600;
    color: var(--gray-900);
}

.header-right {
    display: flex;
    align-items: center;
    gap: 16px;
}

.content {
    flex: 1;
    padding: 32px;
    overflow-y: auto;
}

/* Cards */
.card {
    background: white;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--gray-200);
}

.card-header {
    padding: 20px 24px;
    border-bottom: 1px solid var(--gray-200);
}

.card-title {
    font-size: 16px;
    font-weight: 600;
    color: var(--gray-900);
}

.card-body {
    padding: 24px;
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 10px 16px;
    font-size: 14px;
    font-weight: 500;
    line-height: 1;
    border-radius: var(--border-radius-sm);
    border: 1px solid transparent;
    cursor: pointer;
    transition: all 0.15s;
    text-decoration: none;
    gap: 8px;
}

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

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

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

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

.btn-outline {
    background: white;
    color: var(--gray-700);
    border-color: var(--gray-300);
}

.btn-outline:hover {
    background: var(--gray-50);
    border-color: var(--gray-400);
}

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

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

.btn-sm {
    padding: 6px 12px;
    font-size: 13px;
}

.btn-lg {
    padding: 12px 20px;
    font-size: 15px;
}

/* Forms */
.form-group {
    margin-bottom: 20px;
}

.form-label {
    display: block;
    font-size: 13px;
    font-weight: 500;
    color: var(--gray-700);
    margin-bottom: 6px;
}

.form-control {
    display: block;
    width: 100%;
    padding: 10px 12px;
    font-size: 14px;
    line-height: 1.5;
    color: var(--gray-900);
    background: white;
    border: 1px solid var(--gray-300);
    border-radius: var(--border-radius-sm);
    transition: border-color 0.15s;
}

.form-control:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.1);
}

.form-control::placeholder {
    color: var(--gray-400);
}

.form-select {
    appearance: none;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' fill='none' viewBox='0 0 20 20'%3E%3Cpath stroke='%236B7280' stroke-linecap='round' stroke-linejoin='round' stroke-width='1.5' d='m6 8 4 4 4-4'/%3E%3C/svg%3E");
    background-position: right 8px center;
    background-repeat: no-repeat;
    background-size: 20px;
    padding-right: 36px;
}

textarea.form-control {
    resize: vertical;
    min-height: 100px;
}

/* Tables */
.table {
    width: 100%;
    border-collapse: collapse;
}

.table thead {
    background: var(--gray-50);
    border-bottom: 1px solid var(--gray-200);
}

.table th {
    padding: 12px 16px;
    text-align: left;
    font-size: 12px;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    color: var(--gray-600);
}

.table td {
    padding: 16px;
    border-bottom: 1px solid var(--gray-200);
    color: var(--gray-700);
}

.table tbody tr:hover {
    background: var(--gray-50);
}

/* Badges */
.badge {
    display: inline-flex;
    align-items: center;
    padding: 4px 10px;
    font-size: 12px;
    font-weight: 500;
    border-radius: 9999px;
    line-height: 1;
}

.badge-primary {
    background: rgba(59, 130, 246, 0.1);
    color: var(--primary);
}

.badge-success {
    background: rgba(16, 185, 129, 0.1);
    color: var(--secondary);
}

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

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

.badge-secondary {
    background: var(--gray-100);
    color: var(--gray-700);
}

/* Stats Cards */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 24px;
    margin-bottom: 32px;
}

.stat-card {
    background: white;
    padding: 24px;
    border-radius: var(--border-radius);
    border: 1px solid var(--gray-200);
}

.stat-label {
    font-size: 13px;
    color: var(--gray-600);
    margin-bottom: 8px;
}

.stat-value {
    font-size: 32px;
    font-weight: 700;
    color: var(--gray-900);
    margin-bottom: 4px;
}

.stat-change {
    font-size: 13px;
    font-weight: 500;
}

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

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

/* Alerts */
.alert {
    padding: 16px 20px;
    border-radius: var(--border-radius);
    border: 1px solid;
    margin-bottom: 20px;
}

.alert-info {
    background: rgba(59, 130, 246, 0.1);
    border-color: rgba(59, 130, 246, 0.3);
    color: var(--primary-dark);
}

.alert-success {
    background: rgba(16, 185, 129, 0.1);
    border-color: rgba(16, 185, 129, 0.3);
    color: var(--secondary-dark);
}

.alert-warning {
    background: rgba(245, 158, 11, 0.1);
    border-color: rgba(245, 158, 11, 0.3);
    color: #D97706;
}

.alert-danger {
    background: rgba(239, 68, 68, 0.1);
    border-color: rgba(239, 68, 68, 0.3);
    color: var(--danger-dark);
}

/* User Menu */
.user-menu {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 8px 12px;
    border-radius: var(--border-radius-sm);
    cursor: pointer;
    transition: background 0.15s;
}

.user-menu:hover {
    background: var(--gray-50);
}

.user-avatar {
    width: 36px;
    height: 36px;
    border-radius: 50%;
    background: var(--primary);
    color: white;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 600;
    font-size: 14px;
}

.user-info {
    display: flex;
    flex-direction: column;
    align-items: flex-start;
}

.user-name {
    font-size: 14px;
    font-weight: 500;
    color: var(--gray-900);
}

.user-role {
    font-size: 12px;
    color: var(--gray-500);
}

/* Utilities */
.mt-1 { margin-top: 8px; }
.mt-2 { margin-top: 16px; }
.mt-3 { margin-top: 24px; }
.mt-4 { margin-top: 32px; }

.mb-1 { margin-bottom: 8px; }
.mb-2 { margin-bottom: 16px; }
.mb-3 { margin-bottom: 24px; }
.mb-4 { margin-bottom: 32px; }

.text-center { text-align: center; }
.text-right { text-align: right; }

.flex { display: flex; }
.flex-between { display: flex; justify-content: space-between; align-items: center; }
.gap-2 { gap: 16px; }
.gap-3 { gap: 24px; }

.w-full { width: 100%; }

/* Responsive */
@media (max-width: 768px) {
    .sidebar {
        transform: translateX(-100%);
    }
    
    .main-content {
        margin-left: 0;
    }
    
    .content {
        padding: 16px;
    }
}