:root {
    /* Color Palette - Modern & Vibrant */
    --primary-hue: 220;
    --primary-color: hsl(var(--primary-hue), 85%, 60%);
    --primary-dark: hsl(var(--primary-hue), 85%, 45%);
    --primary-light: hsl(var(--primary-hue), 85%, 75%);

    --secondary-hue: 280;
    --secondary-color: hsl(var(--secondary-hue), 75%, 65%);

    --accent-hue: 340;
    --accent-color: hsl(var(--accent-hue), 85%, 60%);

    --success-color: hsl(145, 70%, 50%);
    --success-light: hsl(145, 70%, 95%);
    --danger-color: hsl(0, 75%, 60%);
    --danger-light: hsl(0, 75%, 95%);
    --warning-color: hsl(40, 90%, 55%);
    --info-color: hsl(200, 85%, 55%);

    /* Neutral Colors */
    --bg-primary: hsl(220, 25%, 10%);
    --bg-secondary: hsl(220, 20%, 15%);
    --bg-tertiary: hsl(220, 20%, 20%);
    --bg-card: hsla(220, 20%, 18%, 0.8);
    --bg-glass: hsla(220, 20%, 25%, 0.4);

    --text-primary: hsl(0, 0%, 95%);
    --text-secondary: hsl(0, 0%, 70%);
    --text-muted: hsl(0, 0%, 50%);

    --border-color: hsla(220, 20%, 40%, 0.3);
    --border-focus: var(--primary-color);

    /* Spacing */
    --space-xs: 0.25rem;
    --space-sm: 0.5rem;
    --space-md: 1rem;
    --space-lg: 1.5rem;
    --space-xl: 2rem;
    --space-2xl: 3rem;

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

    /* Shadows */
    --shadow-sm: 0 2px 4px rgba(0, 0, 0, 0.1);
    --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.2);
    --shadow-lg: 0 10px 25px rgba(0, 0, 0, 0.3);
    --shadow-xl: 0 20px 40px rgba(0, 0, 0, 0.4);
    --shadow-glow: 0 0 20px rgba(59, 130, 246, 0.3);

    /* Typography */
    --font-sans: 'Inter', system-ui, -apple-system, 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: 2rem;

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

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

html {
    font-size: 16px;
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-sans);
    background: linear-gradient(135deg, var(--bg-primary) 0%, var(--bg-secondary) 100%);
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100vh;
    position: relative;
    overflow-x: hidden;
}

/* Animated Background Effect */
body::before {
    content: '';
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background:
        radial-gradient(circle at 20% 30%, hsla(var(--primary-hue), 85%, 60%, 0.1) 0%, transparent 50%),
        radial-gradient(circle at 80% 70%, hsla(var(--secondary-hue), 75%, 65%, 0.1) 0%, transparent 50%);
    pointer-events: none;
    z-index: -1;
}

/* Container */
.container {
    max-width: 1400px;
    margin: 0 auto;
    padding: var(--space-lg);
}

.container-fluid {
    width: 100%;
    padding: var(--space-lg);
}

/* Typography */
h1,
h2,
h3,
h4,
h5,
h6 {
    font-weight: 700;
    line-height: 1.2;
    margin-bottom: var(--space-md);
}

h1 {
    font-size: var(--font-size-3xl);
}

h2 {
    font-size: var(--font-size-2xl);
}

h3 {
    font-size: var(--font-size-xl);
}

h4 {
    font-size: var(--font-size-lg);
}

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

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

/* Navigation - Minimal & Compact */
nav {
    background: hsla(220, 20%, 15%, 0.85);
    border-bottom: 1px solid var(--border-color);
    position: sticky;
    top: 0;
    z-index: 1000;
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    box-shadow: 0 4px 16px rgba(0, 0, 0, 0.3);
}

nav .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--space-md) var(--space-xl);
    max-width: 1600px;
}

.nav-brand {
    font-size: var(--font-size-xl);
    font-weight: 800;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    text-decoration: none;
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    flex-shrink: 0;
}

.nav-links {
    display: flex;
    gap: var(--space-xs);
    list-style: none;
    margin: 0;
    padding: 0;
    align-items: center;
    flex: 1;
    justify-content: center;
}

.nav-links a {
    color: var(--text-secondary);
    text-decoration: none;
    padding: var(--space-sm) var(--space-lg);
    border-radius: var(--radius-md);
    font-size: var(--font-size-sm);
    font-weight: 600;
    transition: all var(--transition-base);
    display: inline-flex;
    align-items: center;
    position: relative;
}

.nav-links a::after {
    content: '';
    position: absolute;
    bottom: 4px;
    left: 50%;
    transform: translateX(-50%) scaleX(0);
    width: 80%;
    height: 2px;
    background: linear-gradient(90deg, var(--primary-color), var(--secondary-color));
    border-radius: 2px;
    transition: transform var(--transition-base);
}

.nav-links a:hover {
    color: var(--primary-color);
    background: var(--bg-glass);
}

.nav-links a:hover::after {
    transform: translateX(-50%) scaleX(1);
}

.nav-links a.active {
    color: var(--primary-color);
    background: hsla(var(--primary-hue), 85%, 60%, 0.15);
}

.nav-links a.active::after {
    transform: translateX(-50%) scaleX(1);
}

/* Grid System */
.grid {
    display: grid;
    gap: var(--space-lg);
}

.grid-2 {
    grid-template-columns: repeat(2, 1fr);
}

.grid-3 {
    grid-template-columns: repeat(3, 1fr);
}

.grid-4 {
    grid-template-columns: repeat(4, 1fr);
}

@media (max-width: 1024px) {
    .grid-4 {
        grid-template-columns: repeat(2, 1fr);
    }

    .grid-3 {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 640px) {

    .grid-2,
    .grid-3,
    .grid-4 {
        grid-template-columns: 1fr;
    }
}

/* Flex Utilities */
.flex {
    display: flex;
}

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

.flex-center {
    justify-content: center;
    align-items: center;
}

.flex-between {
    justify-content: space-between;
    align-items: center;
}

.flex-wrap {
    flex-wrap: wrap;
}

.gap-sm {
    gap: var(--space-sm);
}

.gap-md {
    gap: var(--space-md);
}

.gap-lg {
    gap: var(--space-lg);
}

/* Spacing Utilities */
.mt-sm {
    margin-top: var(--space-sm);
}

.mt-md {
    margin-top: var(--space-md);
}

.mt-lg {
    margin-top: var(--space-lg);
}

.mt-xl {
    margin-top: var(--space-xl);
}

.mb-sm {
    margin-bottom: var(--space-sm);
}

.mb-md {
    margin-bottom: var(--space-md);
}

.mb-lg {
    margin-bottom: var(--space-lg);
}

.mb-xl {
    margin-bottom: var(--space-xl);
}

/* Text Utilities */
.text-center {
    text-align: center;
}

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

.text-muted {
    color: var(--text-muted);
}

.text-secondary {
    color: var(--text-secondary);
}

.text-success {
    color: var(--success-color);
}

.text-danger {
    color: var(--danger-color);
}

.text-warning {
    color: var(--warning-color);
}

/* Font Weights */
.font-bold {
    font-weight: 700;
}

.font-semibold {
    font-weight: 600;
}

.font-medium {
    font-weight: 500;
}

/* Animation Classes */
@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(10px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes slideIn {
    from {
        transform: translateX(-100%);
    }

    to {
        transform: translateX(0);
    }
}

@keyframes pulse {

    0%,
    100% {
        transform: scale(1);
    }

    50% {
        transform: scale(1.05);
    }
}

.fade-in {
    animation: fadeIn 0.5s ease forwards;
    will-change: opacity, transform;
}

.slide-in {
    animation: slideIn 0.3s ease forwards;
    will-change: transform;
}

/* Optimize hover transforms */
.card:hover,
.btn:hover,
.summary-card:hover {
    will-change: transform;
}

/* Loading Spinner - optimized */
.spinner {
    width: 40px;
    height: 40px;
    border: 4px solid var(--bg-tertiary);
    border-top-color: var(--primary-color);
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
    will-change: transform;
}

@keyframes spin {
    to {
        transform: rotate(360deg);
    }
}

.loading-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.7);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 9999;
}

/* Responsive */
@media (max-width: 768px) {
    .container {
        padding: var(--space-md);
    }

    .nav-links {
        gap: var(--space-md);
    }

    h1 {
        font-size: var(--font-size-2xl);
    }

    h2 {
        font-size: var(--font-size-xl);
    }
}