/* ============================================
   Clinical Reference - Main Stylesheet
   WCAG 2.1 AA Compliant | Mobile-First Responsive
   ============================================ */

/* CSS Variables for Theming */
:root {
    /* Colors - Accessible contrast ratios */
    --primary-color: #1e40af;        /* Blue 700 */
    --primary-dark: #1e3a8a;         /* Blue 900 */
    --primary-light: #3b82f6;        /* Blue 500 */
    --secondary-color: #059669;      /* Green 600 */
    --accent-color: #7c3aed;         /* Purple 600 */
    
    --text-primary: #111827;         /* Gray 900 */
    --text-secondary: #4b5563;       /* Gray 600 */
    --text-muted: #6b7280;           /* Gray 500 */
    
    --bg-primary: #ffffff;
    --bg-secondary: #f9fafb;         /* Gray 50 */
    --bg-highlight: #eff6ff;         /* Blue 50 */
    --bg-code: #f3f4f6;              /* Gray 100 */
    
    --border-color: #e5e7eb;         /* Gray 200 */
    --border-dark: #d1d5db;          /* Gray 300 */
    
    /* Typography */
    --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    --font-serif: 'Merriweather', Georgia, serif;
    
    --font-size-base: 18px;
    --font-size-sm: 16px;
    --font-size-xs: 14px;
    --line-height-base: 1.75;
    --line-height-tight: 1.4;
    
    /* Spacing */
    --spacing-xs: 0.5rem;    /* 8px */
    --spacing-sm: 1rem;      /* 16px */
    --spacing-md: 1.5rem;    /* 24px */
    --spacing-lg: 2rem;      /* 32px */
    --spacing-xl: 3rem;      /* 48px */
    --spacing-xxl: 4rem;     /* 64px */
    
    /* Layout */
    --container-width: 1280px;
    --content-width: 65ch;
    --sidebar-width: 280px;
    
    /* 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);
    
    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-base: 200ms ease;
    --transition-slow: 300ms ease;
    
    /* Professional Section Colors */
    --slp-color: #3b82f6;    /* Blue */
    --ot-color: #10b981;     /* Green */
    --pt-color: #f59e0b;     /* Amber */
    --aba-color: #8b5cf6;    /* Purple */
    --educator-color: #ef4444;   /* Red */
    --staff-color: #6b7280;  /* Gray */
}

/* ============================================
   Base Styles
   ============================================ */

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

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

body {
    font-family: var(--font-sans);
    font-size: var(--font-size-base);
    line-height: var(--line-height-base);
    color: var(--text-primary);
    background-color: var(--bg-primary);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* ============================================
   Typography
   ============================================ */

h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-serif);
    font-weight: 700;
    line-height: var(--line-height-tight);
    color: var(--text-primary);
    margin-bottom: var(--spacing-md);
}

h1 {
    font-size: clamp(2rem, 5vw, 3rem);
    margin-bottom: var(--spacing-lg);
}

h2 {
    font-size: clamp(1.75rem, 4vw, 2.25rem);
    margin-top: var(--spacing-xl);
    padding-bottom: var(--spacing-sm);
    border-bottom: 3px solid var(--primary-color);
}

h3 {
    font-size: clamp(1.5rem, 3vw, 1.875rem);
    margin-top: var(--spacing-lg);
    color: var(--primary-dark);
}

h4 {
    font-size: clamp(1.25rem, 2.5vw, 1.5rem);
    margin-top: var(--spacing-md);
}

p {
    margin-bottom: var(--spacing-md);
}

.lead {
    font-size: 1.25rem;
    font-weight: 400;
    color: var(--text-secondary);
}

a {
    color: var(--primary-color);
    text-decoration: underline;
    text-decoration-color: var(--primary-light);
    text-underline-offset: 0.2em;
    transition: color var(--transition-fast);
}

a:hover, a:focus {
    color: var(--primary-dark);
    text-decoration-color: var(--primary-dark);
}

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

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

em {
    font-style: italic;
}

code {
    font-family: 'Monaco', 'Courier New', monospace;
    font-size: 0.9em;
    background-color: var(--bg-code);
    padding: 0.2em 0.4em;
    border-radius: 3px;
    color: var(--text-primary);
}

/* ============================================
   Layout Components
   ============================================ */

.container {
    width: 100%;
    max-width: var(--container-width);
    margin: 0 auto;
    padding: 0 var(--spacing-md);
}

.skip-link {
    position: absolute;
    top: -100px;
    left: var(--spacing-md);
    background: var(--primary-color);
    color: white;
    padding: var(--spacing-sm) var(--spacing-md);
    border-radius: 4px;
    text-decoration: none;
    font-weight: 600;
    z-index: 100;
}

.skip-link:focus {
    top: var(--spacing-md);
}

/* ============================================
   Header & Navigation
   ============================================ */

.site-header {
    background: var(--bg-primary);
    border-bottom: 1px solid var(--border-color);
    padding: var(--spacing-md) 0;
    position: sticky;
    top: 0;
    z-index: 50;
    box-shadow: var(--shadow-sm);
}

.main-nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: var(--spacing-lg);
}

.logo a {
    text-decoration: none;
    color: var(--text-primary);
    display: flex;
    flex-direction: column;
}

.logo strong {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-color);
}

.logo .tagline {
    font-size: var(--font-size-sm);
    color: var(--text-muted);
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: var(--spacing-lg);
}

.nav-menu a {
    text-decoration: none;
    color: var(--text-secondary);
    font-weight: 500;
    padding: var(--spacing-xs) var(--spacing-sm);
    border-radius: 4px;
    transition: all var(--transition-base);
}

.nav-menu a:hover, .nav-menu a:focus {
    color: var(--primary-color);
    background-color: var(--bg-highlight);
}

.mobile-menu-toggle {
    display: none;
    flex-direction: column;
    gap: 4px;
    background: none;
    border: none;
    cursor: pointer;
    padding: var(--spacing-xs);
}

.mobile-menu-toggle span {
    display: block;
    width: 24px;
    height: 2px;
    background-color: var(--text-primary);
    transition: all var(--transition-base);
}

/* ============================================
   Hero Section
   ============================================ */

.hero-section {
    background: linear-gradient(135deg, var(--bg-highlight) 0%, var(--bg-secondary) 100%);
    padding: var(--spacing-xl) 0 var(--spacing-lg);
}

.breadcrumbs {
    display: flex;
    gap: var(--spacing-xs);
    align-items: center;
    font-size: var(--font-size-sm);
    color: var(--text-muted);
    margin-bottom: var(--spacing-md);
}

.breadcrumbs a {
    color: var(--text-muted);
    text-decoration: none;
}

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

.page-title {
    font-size: clamp(2.5rem, 6vw, 3.5rem);
    margin-bottom: var(--spacing-md);
    color: var(--primary-dark);
}

.metadata {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-md);
    align-items: center;
}

.badge {
    display: inline-block;
    padding: var(--spacing-xs) var(--spacing-sm);
    border-radius: 9999px;
    font-size: var(--font-size-xs);
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.badge-verified {
    background-color: #dcfce7;
    color: #166534;
}

.badge-review {
    background-color: #fef3c7;
    color: #92400e;
}

.badge-draft {
    background-color: #e5e7eb;
    color: #374151;
}

.meta-item {
    font-size: var(--font-size-sm);
    color: var(--text-secondary);
}

/* ============================================
   Quick Reference
   ============================================ */

.quick-reference {
    background-color: var(--bg-primary);
    border: 2px solid var(--primary-color);
    border-radius: 8px;
    padding: var(--spacing-lg);
    margin: calc(-1 * var(--spacing-lg)) 0 var(--spacing-xl);
    box-shadow: var(--shadow-md);
}

.quick-ref-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-lg);
}

.quick-ref-item {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xs);
}

.quick-ref-item .label {
    font-size: var(--font-size-sm);
    font-weight: 600;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.quick-ref-item .value {
    font-size: 1.125rem;
    font-weight: 600;
    color: var(--primary-color);
}

.medical-coding {
    margin-top: var(--spacing-lg);
    border-top: 1px solid var(--border-color);
    padding-top: var(--spacing-md);
}

.medical-coding summary {
    cursor: pointer;
    font-weight: 600;
    color: var(--text-secondary);
    padding: var(--spacing-sm);
    margin: calc(-1 * var(--spacing-sm));
}

.medical-coding summary:hover {
    color: var(--primary-color);
}

.coding-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: var(--spacing-sm);
    margin-top: var(--spacing-md);
}

.code-item {
    font-size: var(--font-size-sm);
    color: var(--text-secondary);
}

/* ============================================
   Content Layout
   ============================================ */

.content-layout {
    display: grid;
    grid-template-columns: var(--sidebar-width) 1fr;
    gap: var(--spacing-xl);
    padding: var(--spacing-xl) 0;
}

/* ============================================
   Table of Contents
   ============================================ */

.table-of-contents {
    position: relative;
}

.toc-sticky {
    position: sticky;
    top: calc(80px + var(--spacing-md));
    max-height: calc(100vh - 120px);
    overflow-y: auto;
}

.toc-nav {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xs);
}

.toc-nav h2 {
    font-family: var(--font-sans);
    font-size: 1.125rem;
    font-weight: 700;
    margin: 0 0 var(--spacing-sm);
    padding: 0;
    border: none;
}

.toc-nav a {
    display: block;
    padding: var(--spacing-xs) var(--spacing-sm);
    text-decoration: none;
    color: var(--text-secondary);
    font-size: var(--font-size-sm);
    border-left: 2px solid transparent;
    transition: all var(--transition-fast);
}

.toc-nav a:hover, .toc-nav a:focus {
    color: var(--primary-color);
    border-left-color: var(--primary-color);
    background-color: var(--bg-highlight);
}

.toc-nav a.active {
    color: var(--primary-color);
    border-left-color: var(--primary-color);
    font-weight: 600;
}

/* ============================================
   Article Content
   ============================================ */

.article-content {
    max-width: var(--content-width);
    min-width: 0; /* Prevent grid blowout */
}

.content-section {
    margin-bottom: var(--spacing-xxl);
}

.highlight-section {
    background-color: var(--bg-highlight);
    border-left: 4px solid var(--primary-color);
    padding: var(--spacing-lg);
    border-radius: 4px;
    margin: var(--spacing-xl) calc(-1 * var(--spacing-lg));
}

.subsection {
    margin-top: var(--spacing-lg);
}

/* ============================================
   Lists
   ============================================ */

ul, ol {
    margin-left: var(--spacing-lg);
    margin-bottom: var(--spacing-md);
}

li {
    margin-bottom: var(--spacing-xs);
}

ul li::marker {
    color: var(--primary-color);
}

ol li::marker {
    color: var(--primary-color);
    font-weight: 600;
}

/* ============================================
   Professional Sections
   ============================================ */

.professional-section {
    background-color: var(--bg-secondary);
    border-radius: 8px;
    padding: var(--spacing-lg);
    margin-bottom: var(--spacing-lg);
    border-left: 4px solid var(--text-muted);
}

.professional-section h3 {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    margin-top: 0;
}

.professional-icon {
    font-size: 1.5rem;
}

.slp-section {
    border-left-color: var(--slp-color);
}

.ot-section {
    border-left-color: var(--ot-color);
}

.pt-section {
    border-left-color: var(--pt-color);
}

.aba-section {
    border-left-color: var(--aba-color);
}

.educator-section {
    border-left-color: var(--educator-color);
}

.staff-section {
    border-left-color: var(--staff-color);
}

/* ============================================
   IEP Goals
   ============================================ */

.iep-goals {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-lg);
}

.iep-goal {
    background-color: var(--bg-secondary);
    border-left: 4px solid var(--secondary-color);
    padding: var(--spacing-md);
    border-radius: 4px;
}

.iep-goal h4 {
    margin-top: 0;
    color: var(--secondary-color);
}

/* ============================================
   Resources Section
   ============================================ */

.resources-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: var(--spacing-lg);
}

.resource-category {
    background-color: var(--bg-secondary);
    border-radius: 8px;
    padding: var(--spacing-lg);
}

.resource-category h3 {
    margin-top: 0;
    font-size: 1.25rem;
    color: var(--primary-color);
}

.resource-category ul {
    list-style: none;
    margin-left: 0;
}

.resource-category li {
    margin-bottom: var(--spacing-sm);
}

/* ============================================
   References
   ============================================ */

.references-list {
    font-size: var(--font-size-sm);
    counter-reset: reference-counter;
}

.references-list li {
    counter-increment: reference-counter;
    margin-bottom: var(--spacing-md);
    padding-left: var(--spacing-sm);
}

.references-list li::marker {
    content: counter(reference-counter) ". ";
    font-weight: 600;
}

/* ============================================
   Document Info
   ============================================ */

.document-info {
    margin-top: var(--spacing-xxl);
    padding: var(--spacing-lg);
    background-color: var(--bg-secondary);
    border-radius: 8px;
    font-size: var(--font-size-sm);
}

.info-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-md);
}

.disclaimer {
    color: var(--text-muted);
    font-style: italic;
}

/* ============================================
   Footer
   ============================================ */

.site-footer {
    background-color: var(--text-primary);
    color: white;
    padding: var(--spacing-xxl) 0 var(--spacing-lg);
    margin-top: var(--spacing-xxl);
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-xl);
    margin-bottom: var(--spacing-xl);
}

.footer-section h3 {
    font-family: var(--font-sans);
    font-size: 1.125rem;
    margin-top: 0;
    margin-bottom: var(--spacing-md);
    color: white;
}

.footer-section p {
    font-size: var(--font-size-sm);
    color: #d1d5db;
}

.footer-section ul {
    list-style: none;
    margin-left: 0;
}

.footer-section li {
    margin-bottom: var(--spacing-xs);
}

.footer-section a {
    color: #d1d5db;
    text-decoration: none;
}

.footer-section a:hover {
    color: white;
}

.footer-bottom {
    border-top: 1px solid #374151;
    padding-top: var(--spacing-lg);
    text-align: center;
    font-size: var(--font-size-sm);
    color: #9ca3af;
}

.footer-bottom a {
    color: #9ca3af;
}

.footer-bottom a:hover {
    color: white;
}

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

@media (max-width: 1024px) {
    .content-layout {
        grid-template-columns: 1fr;
    }
    
    .table-of-contents {
        display: none;
    }
    
    .article-content {
        max-width: 100%;
    }
}

@media (max-width: 768px) {
    :root {
        --font-size-base: 17px;
        --spacing-lg: 1.5rem;
        --spacing-xl: 2rem;
        --spacing-xxl: 3rem;
    }
    
    .nav-menu {
        display: none;
    }
    
    .mobile-menu-toggle {
        display: flex;
    }
    
    .quick-ref-grid {
        grid-template-columns: 1fr;
    }
    
    .highlight-section {
        margin-left: calc(-1 * var(--spacing-md));
        margin-right: calc(-1 * var(--spacing-md));
    }
    
    .resources-grid {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 var(--spacing-sm);
    }
    
    h2 {
        font-size: 1.5rem;
    }
    
    h3 {
        font-size: 1.25rem;
    }
}

/* ============================================
   Accessibility Enhancements
   ============================================ */

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

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

/* Screen reader only class */
.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border-width: 0;
}