:root {
    --primary: #6366f1;
    --primary-hover: #4f46e5;
    --primary-light: rgba(99, 102, 241, 0.1);
    --success: #10b981;
    --success-light: rgba(16, 185, 129, 0.1);
    --danger: #ef4444;
    --danger-hover: #dc2626;
    --danger-light: rgba(239, 68, 68, 0.1);
    --warning: #f59e0b;
    --info: #3b82f6;

    --sidebar-width: 260px;
    --topbar-height: 70px;

    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 16px;
    --radius-xl: 24px;

    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);

    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-fast: all 0.15s cubic-bezier(0.4, 0, 0.2, 1);
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    line-height: 1.6;
    min-height: 100vh;
    overflow-x: hidden;
    transition: background-color 0.3s ease, color 0.3s ease;
}

button {
    font-family: inherit;
    cursor: pointer;
    border: none;
    background: none;
}

input, select, textarea {
    font-family: inherit;
}

a {
    text-decoration: none;
    color: inherit;
}

.hidden {
    display: none !important;
}

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

.sidebar {
    position: fixed;
    top: 0;
    left: 0;
    width: var(--sidebar-width);
    height: 100vh;
    background: var(--sidebar-bg);
    border-right: 1px solid var(--border);
    display: flex;
    flex-direction: column;
    z-index: 100;
    transition: transform 0.3s ease;
    backdrop-filter: blur(20px);
}

.sidebar-header {
    padding: 24px 20px;
    display: flex;
    align-items: center;
    gap: 12px;
    border-bottom: 1px solid var(--border);
}

.logo {
    width: 48px;
    height: 48px;
    background: linear-gradient(135deg, var(--primary), #8b5cf6);
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    box-shadow: 0 4px 12px rgba(99, 102, 241, 0.3);
}

.logo-text h2 {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--text-primary);
}

.logo-text span {
    font-size: 0.75rem;
    color: var(--text-secondary);
}

.nav-menu {
    flex: 1;
    padding: 16px 12px;
    display: flex;
    flex-direction: column;
    gap: 4px;
    overflow-y: auto;
}

.nav-item {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 12px 16px;
    border-radius: var(--radius-md);
    color: var(--text-secondary);
    font-weight: 500;
    transition: var(--transition-fast);
    cursor: pointer;
    position: relative;
}

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

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

.nav-item.active::before {
    content: '';
    position: absolute;
    left: 0;
    top: 50%;
    transform: translateY(-50%);
    width: 3px;
    height: 24px;
    background: var(--primary);
    border-radius: 0 3px 3px 0;
}

.nav-icon {
    font-size: 1.25rem;
}

.sidebar-footer {
    padding: 16px;
    border-top: 1px solid var(--border);
}

.user-card {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 12px;
    background: var(--nav-hover);
    border-radius: var(--radius-md);
}

.user-avatar {
    width: 40px;
    height: 40px;
    background: linear-gradient(135deg, var(--primary), #8b5cf6);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.25rem;
}

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

.user-name {
    font-weight: 600;
    font-size: 0.9rem;
    color: var(--text-primary);
}

.user-status {
    font-size: 0.75rem;
    color: var(--success);
}

/* Main content */
.main-content {
    margin-left: var(--sidebar-width);
    min-height: 100vh;
    background: var(--bg);
    transition: margin-left 0.3s ease;
}

.topbar {
    position: sticky;
    top: 0;
    height: var(--topbar-height);
    background: var(--topbar-bg);
    backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--border);
    display: flex;
    align-items: center;
    padding: 0 32px;
    gap: 16px;
    z-index: 50;
}

.menu-toggle {
    display: none;
    font-size: 1.5rem;
    color: var(--text-primary);
    padding: 8px;
}

.topbar-title {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--text-primary);
}

.topbar-actions {
    margin-left: auto;
    display: flex;
    gap: 8px;
}

.theme-toggle {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    background: var(--nav-hover);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.25rem;
    transition: var(--transition-fast);
}

.theme-toggle:hover {
    background: var(--primary-light);
    transform: rotate(20deg);
}

.page-container {
    padding: 32px;
}

.page {
    animation: fadeIn 0.4s ease;
}

.page-header {
    margin-bottom: 24px;
}

.page-header h1 {
    font-size: 2rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 4px;
}

.page-subtitle {
    color: var(--text-secondary);
    font-size: 1rem;
}