/**
* ADVANCED STYLES
* Modern CSS with CSS Variables, Grid, Flexbox
* Optimized for latest browsers
*/

:root {
    /* Advanced Color System */
    --primary-color: #0d6efd;
    --secondary-color: #6f42c1;
    --accent-color: #e83e8c;
    --success-color: #198754;
    --danger-color: #dc3545;
    --warning-color: #ffc107;
    --info-color: #0dcaf0;

    /* Advanced Spacing System */
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-xxl: 3rem;

    /* Advanced Typography */
    --font-family-base: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    --font-family-mono: 'SF Mono', Monaco, 'Cascadia Code', 'Roboto Mono', Consolas, monospace;

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

    /* Advanced Transitions */
    --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-base: 300ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-slow: 500ms cubic-bezier(0.4, 0, 0.2, 1);

    /* Advanced Border Radius */
    --radius-sm: 0.25rem;
    --radius-md: 0.5rem;
    --radius-lg: 1rem;
    --radius-full: 9999px;
}

/* Advanced Reset for Modern Browsers */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    font-size: 16px;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    text-rendering: optimizeLegibility;
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-family-base);
    line-height: 1.6;
    color: #212529;
    background-color: #ffffff;
    overflow-x: hidden;
}

/* Advanced Container System */
.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-md);
}

/* Advanced Grid System */
.grid {
    display: grid;
    gap: var(--spacing-md);
}

.grid-cols-1 { grid-template-columns: repeat(1, 1fr); }
.grid-cols-2 { grid-template-columns: repeat(2, 1fr); }
.grid-cols-3 { grid-template-columns: repeat(3, 1fr); }
.grid-cols-4 { grid-template-columns: repeat(4, 1fr); }

@media (min-width: 768px) {
    .md\:grid-cols-2 { grid-template-columns: repeat(2, 1fr); }
    .md\:grid-cols-3 { grid-template-columns: repeat(3, 1fr); }
    .md\:grid-cols-4 { grid-template-columns: repeat(4, 1fr); }
}

@media (min-width: 1024px) {
    .lg\:grid-cols-3 { grid-template-columns: repeat(3, 1fr); }
    .lg\:grid-cols-4 { grid-template-columns: repeat(4, 1fr); }
}

/* Advanced Flexbox Utilities */
.flex { display: flex; }
.flex-col { flex-direction: column; }
.flex-wrap { flex-wrap: wrap; }
.items-center { align-items: center; }
.justify-center { justify-content: center; }
.justify-between { justify-content: space-between; }
.gap-sm { gap: var(--spacing-sm); }
.gap-md { gap: var(--spacing-md); }
.gap-lg { gap: var(--spacing-lg); }

/* Advanced Button System */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: var(--spacing-sm) var(--spacing-md);
    font-size: 1rem;
    font-weight: 500;
    line-height: 1.5;
    text-align: center;
    text-decoration: none;
    border: 1px solid transparent;
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all var(--transition-base);
    user-select: none;
    -webkit-tap-highlight-color: transparent;
}

.btn:focus {
    outline: 2px solid var(--primary-color);
    outline-offset: 2px;
}

.btn-primary {
    background-color: var(--primary-color);
    color: #ffffff;
}

.btn-primary:hover {
    background-color: #0b5ed7;
    transform: translateY(-1px);
    box-shadow: var(--shadow-md);
}

/* Advanced Card System */
.card {
    background: #ffffff;
    border: 1px solid rgba(0, 0, 0, 0.125);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
    transition: all var(--transition-base);
    overflow: hidden;
}

.card:hover {
    box-shadow: var(--shadow-lg);
    transform: translateY(-2px);
}

/* Advanced Animation System */
@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes slideIn {
    from {
        opacity: 0;
        transform: translateX(-20px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

.animate-fade-in {
    animation: fadeIn var(--transition-base) ease-out;
}

.animate-slide-in {
    animation: slideIn var(--transition-base) ease-out;
}

/* Advanced Performance Optimizations */
img {
    max-width: 100%;
    height: auto;
    display: block;
}

img[loading="lazy"] {
    opacity: 0;
    transition: opacity var(--transition-base);
}

img[loading="lazy"].loaded {
    opacity: 1;
}

/* Advanced GPU Acceleration */
.gpu-accelerated {
    transform: translateZ(0);
    will-change: transform, opacity;
    backface-visibility: hidden;
    perspective: 1000px;
}

/* Advanced Responsive Images */
picture {
    display: block;
}

source {
    display: none;
}

/* Advanced Form Styles */
input, textarea, select {
    width: 100%;
    padding: var(--spacing-sm) var(--spacing-md);
    font-size: 1rem;
    line-height: 1.5;
    color: #212529;
    background-color: #ffffff;
    border: 1px solid #ced4da;
    border-radius: var(--radius-md);
    transition: all var(--transition-fast);
}

input:focus, textarea:focus, select:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(13, 110, 253, 0.1);
}

input.error, textarea.error {
    border-color: var(--danger-color);
}

.error-message {
    color: var(--danger-color);
    font-size: 0.875rem;
    margin-top: var(--spacing-xs);
}

/* Advanced Dark Mode Support */
@media (prefers-color-scheme: dark) {
    :root {
        --text-color: #ffffff;
        --bg-color: #1a1a1a;
    }

    body {
        color: var(--text-color);
        background-color: var(--bg-color);
    }

    .card {
        background: #2d2d2d;
        border-color: #404040;
    }
}

/* Advanced Print Styles */
@media print {
    * {
        background: transparent !important;
        color: #000 !important;
        box-shadow: none !important;
        text-shadow: none !important;
    }

    a, a:visited {
        text-decoration: underline;
    }

    img {
        page-break-inside: avoid;
    }
}

/* Advanced Accessibility */
@media (prefers-reduced-motion: reduce) {
    *, *::before, *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}

/* Advanced Focus Styles */
:focus-visible {
    outline: 2px solid var(--primary-color);
    outline-offset: 2px;
}

/* Advanced Loading States */
.loading {
    position: relative;
    pointer-events: none;
    opacity: 0.6;
}

.loading::after {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 20px;
    height: 20px;
    margin: -10px 0 0 -10px;
    border: 2px solid var(--primary-color);
    border-top-color: transparent;
    border-radius: 50%;
    animation: spin 0.6s linear infinite;
}

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