/* ========================================
   CSS Variables & Design Tokens
   ======================================== */
:root {
    /* Light Mode Colors */
    --color-bg-primary: #ffffff;
    --color-bg-secondary: #f8f9fa;
    --color-bg-tertiary: #e9ecef;
    --color-text-primary: #1a1a1a;
    --color-text-secondary: #6c757d;
    --color-text-tertiary: #adb5bd;
    --color-border: #dee2e6;
    --color-shadow: rgba(0, 0, 0, 0.1);

    /* Brand Colors */
    --color-primary: #6366f1;
    --color-primary-hover: #4f46e5;
    --color-success: #10b981;
    --color-warning: #f59e0b;
    --color-danger: #ef4444;
    --color-info: #3b82f6;

    /* Spacing */
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 0.75rem;
    --spacing-lg: 1rem;
    --spacing-xl: 1.5rem;
    --spacing-2xl: 2rem;

    /* Border Radius */
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;

    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-base: 250ms ease;
    --transition-slow: 350ms ease;

    /* Sidebar */
    --sidebar-width: 240px;
}

/* Dark Mode Colors */
body.dark-mode {
    --color-bg-primary: #0f172a;
    --color-bg-secondary: #1e293b;
    --color-bg-tertiary: #334155;
    --color-text-primary: #f1f5f9;
    --color-text-secondary: #cbd5e1;
    --color-text-tertiary: #94a3b8;
    --color-border: #334155;
    --color-shadow: rgba(0, 0, 0, 0.3);
}

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

body {
    font-family: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto,
        sans-serif;
    background-color: var(--color-bg-primary);
    color: var(--color-text-primary);
    font-size: 14px;
    line-height: 1.5;
    transition: background-color var(--transition-base),
        color var(--transition-base);
}

/* ========================================
   Layout
   ======================================== */
.app-container {
    display: flex;
    min-height: 100vh;
    max-width: 100vw;
    overflow-x: hidden;
}

/* ========================================
   Sidebar
   ======================================== */
.sidebar {
    width: var(--sidebar-width);
    background-color: var(--color-bg-secondary);
    border-right: 1px solid var(--color-border);
    display: flex;
    flex-direction: column;
    position: fixed;
    height: 100vh;
    transition: all var(--transition-base);
}

.sidebar-header {
    padding: var(--spacing-xl) var(--spacing-lg);
    border-bottom: 1px solid var(--color-border);
}

.logo {
    font-size: 1.5rem;
    font-weight: 700;
    background: linear-gradient(
        135deg,
        var(--color-primary),
        var(--color-info)
    );
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.sidebar-nav {
    flex: 1;
    padding: var(--spacing-lg);
    overflow-y: auto;
}

.nav-item {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    padding: var(--spacing-md) var(--spacing-lg);
    margin-bottom: var(--spacing-xs);
    border-radius: var(--radius-md);
    color: var(--color-text-secondary);
    text-decoration: none;
    font-weight: 500;
    transition: all var(--transition-fast);
    position: relative;
    overflow: hidden;
}

.nav-item::before {
    content: "";
    position: absolute;
    left: 0;
    top: 0;
    height: 100%;
    width: 3px;
    background: var(--color-primary);
    transform: scaleY(0);
    transition: transform var(--transition-fast);
}

.nav-item:hover {
    background-color: var(--color-bg-tertiary);
    color: var(--color-text-primary);
    transform: translateX(4px);
}

.nav-item.active {
    background-color: var(--color-bg-tertiary);
    color: var(--color-primary);
}

.nav-item.active::before {
    transform: scaleY(1);
}

.nav-icon {
    width: 20px;
    height: 20px;
    flex-shrink: 0;
}

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

.theme-toggle {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    width: 100%;
    padding: var(--spacing-md) var(--spacing-lg);
    background-color: var(--color-bg-tertiary);
    border: none;
    border-radius: var(--radius-md);
    color: var(--color-text-secondary);
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition-fast);
}

.theme-toggle:hover {
    background-color: var(--color-primary);
    color: white;
    transform: translateY(-2px);
    box-shadow: 0 4px 12px var(--color-shadow);
}

.theme-toggle svg {
    width: 20px;
    height: 20px;
}

.dark-mode .sun-icon {
    display: none;
}

.dark-mode .moon-icon {
    display: block;
}

body:not(.dark-mode) .sun-icon {
    display: block;
}

body:not(.dark-mode) .moon-icon {
    display: none;
}

/* ========================================
   Main Content
   ======================================== */
.main-content {
    flex: 1;
    margin-left: var(--sidebar-width);
    display: flex;
    flex-direction: column;
    min-width: 0;
}

/* ========================================
   Header
   ======================================== */
.header {
    background-color: var(--color-bg-secondary);
    border-bottom: 1px solid var(--color-border);
    padding: var(--spacing-lg) var(--spacing-xl);
    display: flex;
    justify-content: space-between;
    align-items: center;
    position: sticky;
    top: 0;
    z-index: 10;
    backdrop-filter: blur(10px);
}

.page-title {
    font-size: 1.75rem;
    font-weight: 700;
    color: var(--color-text-primary);
}

.header-right {
    display: flex;
    align-items: center;
    gap: var(--spacing-lg);
}

.user-menu {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    padding: var(--spacing-sm) var(--spacing-md);
    background-color: var(--color-bg-tertiary);
    border-radius: var(--radius-lg);
    cursor: pointer;
    transition: all var(--transition-fast);
}

.user-menu:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px var(--color-shadow);
}

.user-avatar {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    border: 2px solid var(--color-primary);
}

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

/* ========================================
   Content Area
   ======================================== */
.content {
    flex: 1;
    padding: var(--spacing-xl);
    background-color: var(--color-bg-primary);
    min-width: 0;
    overflow-x: auto;
}

/* ========================================
   Dashboard Grid
   ======================================== */
.dashboard-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-xl);
}

/* ========================================
   Stat Cards
   ======================================== */
.stat-card {
    background-color: var(--color-bg-secondary);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    padding: var(--spacing-lg);
    display: flex;
    gap: var(--spacing-lg);
    transition: all var(--transition-base);
    position: relative;
    overflow: hidden;
}

.stat-card::before {
    content: "";
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
    background: linear-gradient(90deg, var(--color-primary), var(--color-info));
    transform: scaleX(0);
    transition: transform var(--transition-base);
}

.stat-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 8px 24px var(--color-shadow);
}

.stat-card:hover::before {
    transform: scaleX(1);
}

.stat-icon {
    width: 60px;
    height: 60px;
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
}

.stat-icon svg {
    width: 28px;
    height: 28px;
}

.stat-icon-primary {
    background: linear-gradient(
        135deg,
        rgba(99, 102, 241, 0.1),
        rgba(99, 102, 241, 0.2)
    );
    color: var(--color-primary);
}

.stat-icon-success {
    background: linear-gradient(
        135deg,
        rgba(16, 185, 129, 0.1),
        rgba(16, 185, 129, 0.2)
    );
    color: var(--color-success);
}

.stat-icon-warning {
    background: linear-gradient(
        135deg,
        rgba(245, 158, 11, 0.1),
        rgba(245, 158, 11, 0.2)
    );
    color: var(--color-warning);
}

.stat-icon-info {
    background: linear-gradient(
        135deg,
        rgba(59, 130, 246, 0.1),
        rgba(59, 130, 246, 0.2)
    );
    color: var(--color-info);
}

.stat-content {
    flex: 1;
}

.stat-label {
    font-size: 0.875rem;
    color: var(--color-text-secondary);
    margin-bottom: var(--spacing-xs);
    font-weight: 500;
}

.stat-value {
    font-size: 2rem;
    font-weight: 700;
    color: var(--color-text-primary);
    margin-bottom: var(--spacing-xs);
}

.stat-change {
    font-size: 0.875rem;
    font-weight: 500;
}

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

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

/* ========================================
   Cards
   ======================================== */
.card {
    background-color: var(--color-bg-secondary);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    overflow: hidden;
    transition: all var(--transition-base);
}

.card:hover {
    box-shadow: 0 4px 16px var(--color-shadow);
}

.card-header {
    padding: var(--spacing-lg);
    border-bottom: 1px solid var(--color-border);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

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

.card-action {
    color: var(--color-primary);
    text-decoration: none;
    font-weight: 600;
    font-size: 0.875rem;
    transition: all var(--transition-fast);
}

.card-action:hover {
    color: var(--color-primary-hover);
    transform: translateX(4px);
}

.card-body {
    padding: var(--spacing-lg);
}

/* ========================================
   Activity List
   ======================================== */
.activity-list {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-lg);
}

.activity-item {
    display: flex;
    gap: var(--spacing-md);
    padding: var(--spacing-md);
    border-radius: var(--radius-md);
    transition: all var(--transition-fast);
}

.activity-item:hover {
    background-color: var(--color-bg-tertiary);
}

.activity-avatar {
    flex-shrink: 0;
}

.activity-avatar img {
    width: 48px;
    height: 48px;
    border-radius: 50%;
    border: 2px solid var(--color-border);
}

.activity-content {
    flex: 1;
}

.activity-text {
    color: var(--color-text-primary);
    margin-bottom: var(--spacing-xs);
}

.activity-text strong {
    font-weight: 600;
    color: var(--color-primary);
}

.activity-time {
    font-size: 0.875rem;
    color: var(--color-text-tertiary);
}

/* ========================================
   Responsive Design
   ======================================== */

/* Mobile Menu Button */
.mobile-menu-btn {
    display: none;
    align-items: center;
    justify-content: center;
    background: none;
    border: none;
    color: var(--color-text-primary);
    cursor: pointer;
    padding: var(--spacing-sm);
    margin-right: var(--spacing-md);
    border-radius: var(--radius-md);
    transition: background-color var(--transition-fast);
}

.mobile-menu-btn:hover {
    background-color: var(--color-bg-tertiary);
}

/* Mobile Overlay */
.mobile-overlay {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: rgba(0, 0, 0, 0.5);
    z-index: 40;
    opacity: 0;
    transition: opacity var(--transition-base);
}

.mobile-overlay.active {
    display: block;
    opacity: 1;
}

@media (max-width: 768px) {
    .mobile-menu-btn {
        display: flex;
    }

    .sidebar {
        position: fixed;
        left: 0;
        top: 0;
        z-index: 50;
        transform: translateX(-100%);
        transition: transform var(--transition-base);
    }

    .sidebar.mobile-open {
        transform: translateX(0);
    }

    .main-content {
        margin-left: 0;
    }

    .dashboard-grid {
        grid-template-columns: 1fr;
    }

    .page-title {
        font-size: 1.5rem;
    }

    .header-left {
        display: flex;
        align-items: center;
        max-width: 50%;
    }

    .header-right {
        max-width: 50%;
        justify-content: flex-end;
    }

    .user-menu {
        max-width: 100%;
        min-width: 0;
    }

    .user-name {
        white-space: nowrap;
        overflow: hidden;
        text-overflow: ellipsis;
        flex: 1;
        min-width: 0;
    }
}

/* ========================================
   Scrollbar Styling
   ======================================== */
::-webkit-scrollbar {
    width: 8px;
    height: 8px;
}

::-webkit-scrollbar-track {
    background: var(--color-bg-secondary);
}

::-webkit-scrollbar-thumb {
    background: var(--color-bg-tertiary);
    border-radius: var(--radius-sm);
}

::-webkit-scrollbar-thumb:hover {
    background: var(--color-primary);
}