/* File location: public_html/assets/css/responsive.css */

/* Mobile-first responsive design for Dimensional Relativity */

/* Tablet styles */
@media (max-width: 1024px) {
    .container {
        padding: 0 var(--spacing-md);
    }
    
    .footer-content {
        grid-template-columns: 1fr 1fr;
        gap: var(--spacing-lg);
    }
    
    .about-content {
        grid-template-columns: 1fr;
        gap: var(--spacing-lg);
    }
    
    .prerequisites-content {
        grid-template-columns: 1fr;
        gap: var(--spacing-lg);
    }
    
    .chapter-layout {
        grid-template-columns: 1fr;
        gap: var(--spacing-lg);
    }
    
    .chapter-sidebar {
        position: relative;
        top: 0;
        max-height: none;
        order: -1;
    }
    
    .notes-panel {
        width: 350px;
    }
}

/* Mobile styles */
@media (max-width: 768px) {
    html {
        font-size: 14px;
    }
    
    .container {
        padding: 0 var(--spacing-sm);
    }
    
    /* Navigation */
    .main-navigation .container {
        position: relative;
    }
    
    .nav-menu {
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        background: rgba(10, 14, 39, 0.98);
        backdrop-filter: blur(10px);
        border: 1px solid rgba(255, 255, 255, 0.1);
        border-top: none;
        border-radius: 0 0 12px 12px;
        padding: var(--spacing-md);
        transform: translateY(-10px);
        opacity: 0;
        visibility: hidden;
        transition: var(--transition-normal);
        z-index: 1000;
    }
    
    .nav-menu.active {
        transform: translateY(0);
        opacity: 1;
        visibility: visible;
    }
    
    .nav-links {
        flex-direction: column;
        gap: var(--spacing-sm);
        width: 100%;
    }
    
    .nav-link {
        width: 100%;
        text-align: center;
        padding: var(--spacing-md);
    }
    
    .mobile-menu-toggle {
        display: flex;
    }
    
    .mobile-menu-toggle.active span:nth-child(1) {
        transform: rotate(45deg) translate(5px, 5px);
    }
    
    .mobile-menu-toggle.active span:nth-child(2) {
        opacity: 0;
    }
    
    .mobile-menu-toggle.active span:nth-child(3) {
        transform: rotate(-45deg) translate(7px, -6px);
    }
    
    /* Hero section */
    .hero-content h1 {
        font-size: 2rem;
    }
    
    .hero-subtitle {
        font-size: 1rem;
    }
    
    .hero-actions {
        flex-direction: column;
        align-items: center;
    }
    
    .hero-actions .btn {
        width: 100%;
        max-width: 280px;
        justify-content: center;
    }
    
    /* Typography */
    h1 { font-size: 2rem; }
    h2 { font-size: 1.75rem; }
    h3 { font-size: 1.5rem; }
    
    .chapter-title {
        font-size: 2rem;
        line-height: 1.3;
    }
    
    /* Sections */
    .about-section,
    .book-section,
    .research-preview {
        padding: var(--spacing-xl) 0;
    }
    
    .hero-section {
        padding: var(--spacing-xl) 0;
    }
    
    /* Grids */
    .chapters-grid {
        grid-template-columns: 1fr;
    }
    
    .features-grid {
        grid-template-columns: 1fr;
    }
    
    .research-highlights {
        grid-template-columns: 1fr;
    }
    
    .book-stats {
        flex-direction: column;
        gap: var(--spacing-md);
    }
    
    /* Chapter items */
    .chapter-item {
        flex-direction: column;
        gap: var(--spacing-md);
    }
    
    .chapter-info {
        flex-direction: column;
        gap: var(--spacing-sm);
    }
    
    .chapter-number {
        align-self: flex-start;
        min-width: auto;
    }
    
    .chapter-actions {
        align-self: stretch;
    }
    
    .read-link {
        justify-content: center;
        text-align: center;
        width: 100%;
    }
    
    /* Book header */
    .toc-header {
        flex-direction: column;
        text-align: center;
        gap: var(--spacing-md);
    }
    
    .toc-actions {
        justify-content: center;
        width: 100%;
    }
    
    .toc-actions .btn {
        flex: 1;
        min-width: 0;
    }
    
    /* Chapter header */
    .chapter-meta {
        justify-content: center;
        text-align: center;
    }
    
    .chapter-actions {
        justify-content: center;
        flex-wrap: wrap;
    }
    
    .chapter-actions .btn {
        flex: 1;
        min-width: 120px;
    }
    
    /* Chapter footer navigation */
    .chapter-footer-nav {
        grid-template-columns: 1fr;
        gap: var(--spacing-sm);
    }
    
    .footer-nav-link.next {
        text-align: left;
    }
    
    /* Footer */
    .footer-content {
        grid-template-columns: 1fr;
        gap: var(--spacing-lg);
        text-align: center;
    }
    
    .footer-bottom {
        flex-direction: column;
        gap: var(--spacing-md);
        text-align: center;
    }
    
    .footer-meta {
        text-align: center;
    }
    
    .footer-social {
        justify-content: center;
    }
    
    /* Search */
    .search-container {
        padding: 0 var(--spacing-md);
    }
    
    .search-form {
        flex-direction: column;
    }
    
    .search-input {
        font-size: 1rem;
    }
    
    /* Notes panel */
    .notes-panel {
        width: 100%;
        right: -100%;
    }
    
    .notes-panel.active {
        right: 0;
    }
    
    /* Chapter sidebar */
    .chapter-sidebar {
        position: static;
        transform: none;
        opacity: 1;
        max-height: none;
        margin-bottom: var(--spacing-lg);
    }
    
    .chapter-sidebar.visible {
        transform: none;
    }
    
    /* Content adjustments */
    .content-body {
        padding: var(--spacing-lg);
    }
    
    .content-body h2 {
        margin-top: var(--spacing-xl);
    }
    
    /* Utility classes for mobile */
    .mobile-hidden {
        display: none;
    }
    
    .mobile-center {
        text-align: center;
    }
    
    .mobile-full-width {
        width: 100%;
    }
}

/* Small mobile styles */
@media (max-width: 480px) {
    html {
        font-size: 13px;
    }
    
    .container {
        padding: 0 var(--spacing-xs);
    }
    
    .hero-content h1 {
        font-size: 1.75rem;
    }
    
    .chapter-title {
        font-size: 1.75rem;
    }
    
    .btn {
        padding: var(--spacing-sm) var(--spacing-md);
        font-size: 0.875rem;
    }
    
    .chapter-item {
        padding: var(--spacing-md);
    }
    
    .content-body {
        padding: var(--spacing-md);
    }
    
    .book-header,
    .chapter-header {
        padding: var(--spacing-lg) 0;
    }
    
    .hero-section {
        padding: var(--spacing-lg) 0;
    }
    
    .about-section,
    .book-section,
    .research-preview {
        padding: var(--spacing-lg) 0;
    }
    
    .equation {
        font-size: 1.25rem;
    }
    
    .hero-equation {
        padding: var(--spacing-md);
    }
    
    .search-close {
        top: -40px;
        font-size: 1.5rem;
    }
}

/* Large desktop styles */
@media (min-width: 1400px) {
    .container {
        max-width: 1400px;
    }
    
    .hero-content h1 {
        font-size: 3.5rem;
    }
    
    .chapter-title {
        font-size: 3rem;
    }
    
    .chapter-layout {
        grid-template-columns: 350px 1fr;
        gap: var(--spacing-2xl);
    }
    
    .chapters-grid {
        grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    }
}

/* Print styles */
@media print {
    * {
        color: #000 !important;
        background: white !important;
        box-shadow: none !important;
    }
    
    .site-header,
    .site-footer,
    .chapter-sidebar,
    .chapter-actions,
    .notes-panel,
    .search-overlay {
        display: none !important;
    }
    
    .main-content {
        margin: 0;
        padding: 0;
    }
    
    .chapter-content,
    .content-body {
        background: white !important;
        border: none !important;
        box-shadow: none !important;
    }
    
    .chapter-title {
        border-bottom: 2px solid #000;
        padding-bottom: 10px;
    }
    
    a {
        text-decoration: underline;
    }
    
    .btn {
        border: 1px solid #000;
        padding: 5px 10px;
        text-decoration: none;
    }
}

/* Accessibility improvements */
@media (prefers-reduced-motion: reduce) {
    * {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
    
    .search-overlay,
    .notes-panel,
    .chapter-sidebar {
        transition: none;
    }
}

/* High contrast mode */
@media (prefers-contrast: high) {
    :root {
        --primary-bg: #000000;
        --secondary-bg: #1a1a1a;
        --surface-bg: #ffffff;
        --primary-text: #ffffff;
        --dark-text: #000000;
        --accent-text: #0066cc;
        --brand-primary: #0066cc;
    }
    
    .chapter-item,
    .feature-card,
    .highlight-card {
        border-width: 2px;
    }
    
    .btn {
        border-width: 2px;
        font-weight: 600;
    }
}

/* Focus styles for keyboard navigation */
@media (any-hover: none) {
    .nav-link:focus,
    .btn:focus,
    .search-input:focus,
    .toc-link:focus {
        outline: 2px solid var(--brand-primary);
        outline-offset: 2px;
    }
}