:root {
    --primary: #4f46e5;
    /* Indigo 600 */
    --primary-hover: #4338ca;
    /* Indigo 700 */
    --secondary: #0ea5e9;
    /* Sky 500 */
    --accent: #f43f5e;
    /* Rose 500 */
    --text-main: #0f172a;
    /* Slate 900 */
    --text-muted: #64748b;
    /* Slate 500 */
    --bg-body: #f8fafc;
    /* Slate 50 */
    --bg-white: #ffffff;
    --border-light: #e2e8f0;
    /* Slate 200 */
    --shadow-sm: 0 1px 3px 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);
    --radius: 1rem;
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Inter', sans-serif;
    background-color: var(--bg-body);
    color: var(--text-main);
    line-height: 1.6;
    overflow-x: hidden;
}

h1,
h2,
h3,
h4,
.font-heading {
    font-family: 'Outfit', sans-serif;
    font-weight: 700;
    color: var(--text-main);
}

a {
    text-decoration: none;
    color: inherit;
}

ul {
    list-style: none;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1.5rem;
}

.hidden {
    display: none !important;
}

/* --- Header --- */
header {
    background: rgba(255, 255, 255, 0.9);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border-light);
    position: sticky;
    top: 0;
    z-index: 1000;
    padding: 1rem 0;
}

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

.logo {
    font-size: 1.5rem;
    font-weight: 800;
    letter-spacing: -0.5px;
    color: var(--primary);
    display: flex;
    align-items: center;
    gap: 0;
}

.logo span {
    color: var(--secondary);
}

nav ul {
    display: flex;
    gap: 2rem;
    align-items: center;
}

nav ul a {
    font-weight: 500;
    color: var(--text-muted);
    transition: var(--transition);
}

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

/* --- Buttons --- */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.75rem 1.5rem;
    border-radius: 0.5rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    border: none;
    font-size: 1rem;
    gap: 0.5rem;
}

.btn-primary {
    background: var(--primary);
    color: white;
    box-shadow: 0 4px 6px -1px rgba(79, 70, 229, 0.2);
}

.btn-primary:hover {
    background: var(--primary-hover);
    transform: translateY(-2px);
    box-shadow: 0 10px 15px -3px rgba(79, 70, 229, 0.3);
}

.btn-outline {
    background: transparent;
    border: 1px solid var(--border-light);
    color: var(--text-main);
}

.btn-outline:hover {
    border-color: var(--primary);
    color: var(--primary);
    background: #eff6ff;
}

.btn-lg {
    padding: 1rem 2rem;
    font-size: 1.125rem;
}

.btn-block {
    width: 100%;
}

/* --- Hero --- */
#hero {
    padding: 8rem 0 6rem;
    text-align: center;
    background: radial-gradient(circle at top center, #e0e7ff 0%, transparent 60%);
}

.hero-content {
    max-width: 800px;
    margin: 0 auto;
}

.hero-content h1 {
    font-size: 3.5rem;
    line-height: 1.2;
    margin-bottom: 1.5rem;
}

.hero-content h1 span {
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
}

.hero-content p {
    font-size: 1.25rem;
    color: var(--text-muted);
    margin-bottom: 2.5rem;
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

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

/* --- Features Grid --- */
.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    padding: 4rem 0;
}

.feature-card {
    background: var(--bg-white);
    padding: 2rem;
    border-radius: var(--radius);
    border: 1px solid var(--border-light);
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
}

.feature-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
    border-color: var(--primary);
}

.icon-box {
    width: 4rem;
    height: 4rem;
    background: #eff6ff;
    border-radius: 0.75rem;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 1.5rem;
    color: var(--primary);
}

.icon-box svg {
    width: 2rem;
    height: 2rem;
}

.feature-card h3 {
    font-size: 1.25rem;
    margin-bottom: 0.75rem;
}

.feature-card p {
    color: var(--text-muted);
    font-size: 0.95rem;
}

/* --- Generic Section Styles --- */
.section-head {
    text-align: center;
    max-width: 700px;
    margin: 0 auto 3rem;
}

.section-head h2 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
}

.section-head p {
    color: var(--text-muted);
    font-size: 1.1rem;
}

.content-box {
    background: var(--bg-white);
    padding: 3rem;
    border-radius: var(--radius);
    border: 1px solid var(--border-light);
    box-shadow: var(--shadow-sm);
    margin-bottom: 4rem;
}

/* --- FAQ Accordion --- */
.faq-item {
    border-bottom: 1px solid var(--border-light);
    margin-bottom: 1rem;
}

.faq-question {
    width: 100%;
    text-align: left;
    padding: 1.25rem 0;
    background: none;
    border: none;
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--text-main);
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.faq-question:hover {
    color: var(--primary);
}

.faq-toggle-icon {
    font-size: 1.5rem;
    font-weight: 300;
    transition: transform 0.3s ease;
}

.faq-item.active .faq-toggle-icon {
    transform: rotate(45deg);
}

.faq-answer {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease-out;
    color: var(--text-muted);
}

.faq-answer p {
    padding-bottom: 1.5rem;
}

/* --- Pricing --- */
.pricing-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 2rem;
    max-width: 900px;
    margin: 0 auto;
}

.pricing-card {
    background: var(--bg-white);
    border-radius: var(--radius);
    padding: 2.5rem;
    border: 1px solid var(--border-light);
    text-align: center;
    position: relative;
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
}

.pricing-card.featured {
    border-color: var(--primary);
    box-shadow: var(--shadow-lg);
}

.badge {
    position: absolute;
    top: 1rem;
    right: 1rem;
    background: var(--primary);
    color: white;
    padding: 0.25rem 0.75rem;
    border-radius: 1rem;
    font-size: 0.75rem;
    font-weight: 700;
    text-transform: uppercase;
}

.price {
    font-size: 3rem;
    font-weight: 700;
    color: var(--text-main);
    margin: 1.5rem 0;
}

.price span {
    font-size: 1rem;
    color: var(--text-muted);
    font-weight: 400;
}

.features-list {
    text-align: left;
    margin: 2rem 0;
}

.features-list li {
    padding: 0.5rem 0;
    color: var(--text-muted);
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.features-list li svg {
    color: #10b981;
    width: 1.25rem;
    height: 1.25rem;
}

/* --- Footer --- */
footer {
    background: #0f172a;
    color: #f8fafc;
    padding: 4rem 0 2rem;
    margin-top: 6rem;
}

.footer-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 3rem;
    margin-bottom: 3rem;
}

.footer-col h4 {
    color: white;
    margin-bottom: 1.5rem;
    font-size: 1.1rem;
}

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

.footer-col ul li {
    margin-bottom: 0.75rem;
}

.footer-col ul a {
    color: #94a3b8;
    transition: color 0.2s;
}

.footer-col ul a:hover {
    color: white;
}

.footer-disclaimer {
    border-top: 1px solid #1e293b;
    padding-top: 2rem;
    color: #64748b;
    font-size: 0.9rem;
    text-align: center;
}

/* --- Test Interface --- */
.test-card {
    background: var(--bg-white);
    max-width: 800px;
    margin: 4rem auto;
    padding: 3rem;
    border-radius: var(--radius);
    box-shadow: var(--shadow-lg);
}

.progress-container {
    background: #f1f5f9;
    height: 0.5rem;
    border-radius: 1rem;
    margin-top: 2rem;
    overflow: hidden;
}

#progress {
    background: var(--primary);
    height: 100%;
    width: 0;
    transition: width 0.3s ease;
}

.option-btn {
    width: 100%;
    padding: 1rem;
    border: 1px solid var(--border-light);
    background: white;
    border-radius: 0.5rem;
    text-align: left;
    font-size: 1rem;
    cursor: pointer;
    transition: var(--transition);
    color: var(--text-main);
}

.option-btn:hover {
    border-color: var(--primary);
    background: #f5f3ff;
}

/* --- Responsive --- */
@media (max-width: 768px) {
    .hero-content h1 {
        font-size: 2.5rem;
    }

    nav ul {
        display: none;
        /* Simplification for task focus */
    }
}

/* --- Research Section --- */
#research {
    background: #f8fafc;
    padding: 6rem 0;
    margin-top: 4rem;
}

.research-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    align-items: center;
}

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

.research-content h2 {
    font-size: 2.5rem;
    margin-bottom: 1.5rem;
}

.research-content p {
    color: var(--text-muted);
    font-size: 1.1rem;
    margin-bottom: 1.5rem;
    line-height: 1.8;
}

.research-stat {
    display: flex;
    gap: 3rem;
    margin-top: 3rem;
}

.stat-item h4 {
    font-size: 2.5rem;
    color: var(--primary);
    line-height: 1;
    margin-bottom: 0.5rem;
}

.stat-item span {
    color: var(--text-muted);
    font-size: 0.9rem;
    font-weight: 500;
}

.research-visual {
    position: relative;
}

.image-canvas {
    background: linear-gradient(135deg, #e0e7ff 0%, #cbd5e1 100%);
    border-radius: 2rem;
    height: 400px;
    width: 100%;
    position: relative;
    overflow: hidden;
    box-shadow: var(--shadow-lg);
}

.location-tag {
    position: absolute;
    bottom: 2rem;
    left: 2rem;
    background: rgba(255, 255, 255, 0.9);
    backdrop-filter: blur(4px);
    padding: 0.75rem 1.25rem;
    border-radius: 2rem;
    font-weight: 600;
    font-size: 0.9rem;
    box-shadow: var(--shadow-sm);
    display: flex;
    align-items: center;
    gap: 0.5rem;
}