/* Reset and Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    /* Colors */
    --primary-50: #eff6ff;
    --primary-100: #dbeafe;
    --primary-200: #bfdbfe;
    --primary-300: #93c5fd;
    --primary-400: #60a5fa;
    --primary-500: #3b82f6;
    --primary-600: #2563eb;
    --primary-700: #1d4ed8;
    --primary-800: #1e40af;
    --primary-900: #1e3a8a;
    
    --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;
    
    --success-50: #f0fdf4;
    --success-500: #22c55e;
    --success-600: #16a34a;
    
    --warning-50: #fffbeb;
    --warning-500: #f59e0b;
    --warning-600: #d97706;
    
    --error-50: #fef2f2;
    --error-500: #ef4444;
    --error-600: #dc2626;
    
    /* Typography */
    --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --font-size-xs: 0.75rem;
    --font-size-sm: 0.875rem;
    --font-size-base: 1rem;
    --font-size-lg: 1.125rem;
    --font-size-xl: 1.25rem;
    --font-size-2xl: 1.5rem;
    --font-size-3xl: 1.875rem;
    --font-size-4xl: 2.25rem;
    
    /* Spacing */
    --spacing-1: 0.25rem;
    --spacing-2: 0.5rem;
    --spacing-3: 0.75rem;
    --spacing-4: 1rem;
    --spacing-5: 1.25rem;
    --spacing-6: 1.5rem;
    --spacing-8: 2rem;
    --spacing-10: 2.5rem;
    --spacing-12: 3rem;
    --spacing-16: 4rem;
    --spacing-20: 5rem;
    
    /* Shadows */
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow-base: 0 1px 3px 0 rgb(0 0 0 / 0.1), 0 1px 2px -1px rgb(0 0 0 / 0.1);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
    --shadow-xl: 0 20px 25px -5px rgb(0 0 0 / 0.1), 0 8px 10px -6px rgb(0 0 0 / 0.1);
    
    /* Border Radius */
    --radius-sm: 0.25rem;
    --radius-base: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;
    --radius-full: 9999px;
    
    /* Transitions */
    --transition-fast: 150ms ease-in-out;
    --transition-base: 200ms ease-in-out;
    --transition-slow: 300ms ease-in-out;
    
    /* Layout */
    --navbar-height: 4rem;
    --sidebar-width: 16rem;
    --container-max-width: 1200px;
}

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

/* Loading Overlay */
.loading-overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: rgba(255, 255, 255, 0.9);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 9999;
    transition: opacity var(--transition-base);
}

.loading-overlay.hidden {
    opacity: 0;
    pointer-events: none;
}

.loading-spinner {
    text-align: center;
}

.spinner {
    width: 3rem;
    height: 3rem;
    border: 3px solid var(--gray-200);
    border-top: 3px solid var(--primary-600);
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin: 0 auto var(--spacing-4);
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

/* Navigation */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: var(--navbar-height);
    background-color: white;
    border-bottom: 1px solid var(--gray-200);
    z-index: 1000;
    box-shadow: var(--shadow-sm);
}

.nav-container {
    max-width: var(--container-max-width);
    margin: 0 auto;
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 var(--spacing-6);
}

.nav-brand {
    display: flex;
    align-items: center;
    gap: var(--spacing-3);
    font-weight: 600;
    color: var(--gray-900);
}

.nav-icon {
    width: 1.5rem;
    height: 1.5rem;
    color: var(--primary-600);
}

.nav-title {
    font-size: var(--font-size-lg);
}

.nav-menu {
    display: flex;
    align-items: center;
    gap: var(--spacing-8);
}

.nav-link {
    display: flex;
    align-items: center;
    gap: var(--spacing-2);
    padding: var(--spacing-2) var(--spacing-4);
    color: var(--gray-600);
    text-decoration: none;
    border-radius: var(--radius-md);
    transition: all var(--transition-fast);
    font-weight: 500;
}

.nav-link:hover,
.nav-link.active {
    color: var(--primary-600);
    background-color: var(--primary-50);
}

.nav-link i {
    width: 1.125rem;
    height: 1.125rem;
}

.nav-actions {
    display: flex;
    align-items: center;
    gap: var(--spacing-4);
}

.user-menu {
    position: relative;
}

.user-button {
    display: flex;
    align-items: center;
    gap: var(--spacing-2);
    padding: var(--spacing-2) var(--spacing-3);
    background: none;
    border: 1px solid var(--gray-200);
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all var(--transition-fast);
}

.user-button:hover {
    background-color: var(--gray-50);
    border-color: var(--gray-300);
}

.user-icon {
    width: 1.25rem;
    height: 1.25rem;
    color: var(--gray-600);
}

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

.chevron {
    width: 1rem;
    height: 1rem;
    color: var(--gray-400);
    transition: transform var(--transition-fast);
}

.user-menu.open .chevron {
    transform: rotate(180deg);
}

.user-dropdown {
    position: absolute;
    top: 100%;
    right: 0;
    margin-top: var(--spacing-2);
    background: white;
    border: 1px solid var(--gray-200);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-lg);
    min-width: 12rem;
    opacity: 0;
    visibility: hidden;
    transform: translateY(-0.5rem);
    transition: all var(--transition-fast);
}

.user-menu.open .user-dropdown {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.dropdown-item {
    display: flex;
    align-items: center;
    gap: var(--spacing-3);
    width: 100%;
    padding: var(--spacing-3) var(--spacing-4);
    color: var(--gray-700);
    text-decoration: none;
    background: none;
    border: none;
    cursor: pointer;
    transition: background-color var(--transition-fast);
    font-size: var(--font-size-sm);
}

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

.dropdown-item i {
    width: 1rem;
    height: 1rem;
}

.dropdown-divider {
    margin: var(--spacing-2) 0;
    border: none;
    border-top: 1px solid var(--gray-200);
}

.mobile-menu-btn {
    display: none;
    background: none;
    border: none;
    cursor: pointer;
    padding: var(--spacing-2);
    color: var(--gray-600);
}

.mobile-menu-btn i {
    width: 1.5rem;
    height: 1.5rem;
}

/* Main Content */
.main-content {
    margin-top: var(--navbar-height);
    min-height: calc(100vh - var(--navbar-height));
}

.page {
    max-width: var(--container-max-width);
    margin: 0 auto;
    padding: var(--spacing-8) var(--spacing-6);
}

.page.hidden {
    display: none;
}

.page-header {
    display: flex;
    align-items: flex-start;
    justify-content: space-between;
    margin-bottom: var(--spacing-8);
    gap: var(--spacing-6);
}

.page-title h1 {
    font-size: var(--font-size-3xl);
    font-weight: 700;
    color: var(--gray-900);
    margin-bottom: var(--spacing-2);
}

.page-title p {
    color: var(--gray-600);
    font-size: var(--font-size-lg);
}

.page-actions {
    display: flex;
    align-items: center;
    gap: var(--spacing-4);
    flex-shrink: 0;
}

/* Utility Classes */
.hidden {
    display: none !important;
}

.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}

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

.text-left {
    text-align: left;
}

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

.flex {
    display: flex;
}

.flex-col {
    flex-direction: column;
}

.items-center {
    align-items: center;
}

.justify-center {
    justify-content: center;
}

.justify-between {
    justify-content: space-between;
}

.gap-2 {
    gap: var(--spacing-2);
}

.gap-4 {
    gap: var(--spacing-4);
}

.gap-6 {
    gap: var(--spacing-6);
}

.w-full {
    width: 100%;
}

.h-full {
    height: 100%;
}

.mb-4 {
    margin-bottom: var(--spacing-4);
}

.mb-6 {
    margin-bottom: var(--spacing-6);
}

.mt-4 {
    margin-top: var(--spacing-4);
}

.mt-6 {
    margin-top: var(--spacing-6);
}

/* Responsive Design */
@media (max-width: 768px) {
    .nav-menu {
        display: none;
    }
    
    .mobile-menu-btn {
        display: block;
    }
    
    .nav-container {
        padding: 0 var(--spacing-4);
    }
    
    .page {
        padding: var(--spacing-6) var(--spacing-4);
    }
    
    .page-header {
        flex-direction: column;
        align-items: stretch;
        gap: var(--spacing-4);
    }
    
    .page-actions {
        flex-wrap: wrap;
    }
    
    .nav-title {
        display: none;
    }
}

@media (max-width: 480px) {
    .page {
        padding: var(--spacing-4) var(--spacing-3);
    }
    
    .page-title h1 {
        font-size: var(--font-size-2xl);
    }
}