:root {
    --primary-color: #0056b3; /* Deep Blue */
    --primary-dark: #004494;
    --secondary-color: #f8f9fa; /* Light Gray */
    --accent-color: #ffc107; /* Gold/Yellow for attention */
    --text-dark: #333333;
    --text-light: #666666;
    --white: #ffffff;
    --border-color: #dddddd;
    --success-color: #28a745;
    --spacing-unit: 1rem;
    --container-width: 1200px;
    --shadow-sm: 0 2px 4px rgba(0,0,0,0.1);
    --shadow-md: 0 4px 6px rgba(0,0,0,0.1);
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    line-height: 1.6;
    color: var(--text-dark);
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}

/* Layout Utilities */
.container {
    width: 100%;
    max-width: var(--container-width);
    margin: 0 auto;
    padding: 0 var(--spacing-unit);
}

.grid {
    display: grid;
    gap: calc(var(--spacing-unit) * 2);
}

.grid-2 {
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
}

.grid-3 {
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
}

.section {
    padding: calc(var(--spacing-unit) * 4) 0;
}

.section-light {
    background-color: var(--secondary-color);
}

.section-dark {
    background-color: var(--text-dark);
    color: var(--white);
}

/* Typography Utilities */
h1, h2, h3, h4, h5, h6 {
    line-height: 1.2;
    margin-bottom: var(--spacing-unit);
    color: var(--text-dark);
}

.section-dark h1, .section-dark h2, .section-dark h3 {
    color: var(--white);
}

.heading-1 { font-size: 2.5rem; }
.heading-2 { font-size: 2rem; }
.heading-3 { font-size: 1.5rem; }

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

ul {
    list-style-position: inside;
}

a {
    color: var(--primary-color);
    text-decoration: none;
    transition: color 0.2s;
}

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

/* Button Utilities */
.btn {
    display: inline-block;
    padding: 0.75rem 1.5rem;
    border-radius: 4px;
    font-weight: 600;
    text-decoration: none;
    cursor: pointer;
    border: none;
    transition: background-color 0.2s, transform 0.1s;
    text-align: center;
}

.btn:active {
    transform: translateY(1px);
}

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

.btn-primary:hover {
    background-color: var(--primary-dark);
    text-decoration: none;
    color: var(--white);
}

.btn-secondary {
    background-color: var(--secondary-color);
    color: var(--text-dark);
    border: 1px solid var(--border-color);
}

.btn-secondary:hover {
    background-color: #e2e6ea;
    text-decoration: none;
}

/* Header & Navigation */
.navbar {
    background-color: var(--white);
    box-shadow: var(--shadow-sm);
    padding: 1rem 0;
    position: sticky;
    top: 0;
    z-index: 1000;
}

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

.logo {
    font-size: 1.5rem;
    font-weight: bold;
    color: var(--primary-color);
    text-decoration: none;
}

.nav-links {
    display: flex;
    align-items: center;
    gap: 1.5rem;
}

.nav-links a:not(.btn) {
    color: var(--text-dark);
    font-weight: 500;
    text-decoration: none;
}

.nav-links a:not(.btn):hover {
    color: var(--primary-color);
}

.mobile-menu-toggle {
    display: none;
    background: none;
    border: none;
    cursor: pointer;
    flex-direction: column;
    gap: 5px;
}

.mobile-menu-toggle span {
    display: block;
    width: 25px;
    height: 3px;
    background-color: var(--text-dark);
    transition: 0.3s;
}

/* Mobile Navigation */
@media (max-width: 900px) {
    .mobile-menu-toggle {
        display: flex;
    }

    .nav-links {
        display: none; /* Hidden by default on mobile */
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        background-color: var(--white);
        flex-direction: column;
        padding: 1rem;
        box-shadow: var(--shadow-md);
        text-align: center;
    }

    .nav-links.active {
        display: flex;
    }

    .nav-links a {
        padding: 0.5rem 0;
        display: block;
        width: 100%;
    }
}

/* Hero Section */
.hero {
    background: linear-gradient(rgba(0,0,0,0.6), rgba(0,0,0,0.6)), url('https://images.unsplash.com/photo-1449844908441-8829872d2607?auto=format&fit=crop&q=80&w=1200'); /* Placeholder image of Chicago Skyline/Architecture */
    background-size: cover;
    background-position: center;
    color: var(--white);
    padding: 6rem 0;
    text-align: center;
}

.hero h1 {
    color: var(--white);
    font-size: 3rem;
    margin-bottom: 1rem;
}

.hero p {
    font-size: 1.25rem;
    margin-bottom: 2rem;
    max-width: 800px;
    margin-left: auto;
    margin-right: auto;
}

.hero-buttons {
    display: flex;
    gap: 1rem;
    justify-content: center;
    flex-wrap: wrap;
}

/* Cards */
.card {
    background-color: var(--white);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: 1.5rem;
    transition: transform 0.2s, box-shadow 0.2s;
}

.card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-md);
}

.card h3 {
    color: var(--primary-color);
    margin-bottom: 0.5rem;
}

.card-meta {
    font-size: 0.9rem;
    color: var(--text-light);
    margin-bottom: 1rem;
}

/* FAQ Styles */
.faq-item {
    border-bottom: 1px solid var(--border-color);
    padding: 1rem 0;
}

.faq-item:last-child {
    border-bottom: none;
}

.faq-item h3 {
    font-size: 1.2rem;
    cursor: pointer;
    margin-bottom: 0.5rem;
    color: var(--primary-color);
}

/* Content Pages */
.content h2 {
    margin-top: 2rem;
    border-bottom: 2px solid var(--border-color);
    padding-bottom: 0.5rem;
}

/* Rehab Checklist */
.checklist-section {
    margin-bottom: 2rem;
    background: var(--white);
    padding: 1.5rem;
    border: 1px solid var(--border-color);
    border-radius: 8px;
}

.checklist-item {
    display: flex;
    align-items: flex-start;
    margin-bottom: 0.75rem;
}

.checklist-item input[type="checkbox"] {
    margin-top: 0.35em;
    margin-right: 0.75em;
    width: 1.2em;
    height: 1.2em;
}

/* Detail Views */
.detail-view {
    background-color: var(--white);
    padding: 2rem;
    border-radius: 8px;
    box-shadow: var(--shadow-sm);
}

.detail-view h1 {
    border-bottom: 3px solid var(--primary-color);
    padding-bottom: 0.5rem;
    margin-bottom: 1.5rem;
}

.detail-grid {
    display: grid;
    grid-template-columns: 2fr 1fr;
    gap: 2rem;
}

@media (max-width: 768px) {
    .detail-grid {
        grid-template-columns: 1fr;
    }
}

.detail-sidebar {
    background-color: var(--secondary-color);
    padding: 1.5rem;
    border-radius: 8px;
}

/* Footer */
.site-footer {
    background-color: #2c3e50;
    color: #ecf0f1;
    padding-top: 3rem;
    margin-top: auto;
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
    padding-bottom: 2rem;
}

.footer-content h3, .footer-content h4 {
    color: var(--white);
    margin-bottom: 1rem;
}

.footer-links ul {
    list-style: none;
}

.footer-links li {
    margin-bottom: 0.5rem;
}

.footer-links a {
    color: #bdc3c7;
    text-decoration: none;
}

.footer-links a:hover {
    color: var(--white);
}

.footer-bottom {
    border-top: 1px solid rgba(255,255,255,0.1);
    padding: 1rem 0;
    text-align: center;
    font-size: 0.9rem;
    color: #95a5a6;
}

/* Utility Animations */
@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

.fade-in {
    animation: fadeIn 0.4s ease-out forwards;
}