/* Reset and Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --primary-navy: #0B1E3F;
    --accent-blue: #3C6FFF;
    --accent-blue-dark: #2557E8;
    --highlight-teal: #17D4D1;
    --light-bg: #F4F6FA;
    --white: #ffffff;
    --text-dark: #1a1a1a;
    --text-mid: #4a4a4a;
    --text-light: #6b7280;
    --border-light: #e5e7eb;
    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.1);
    --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 25px rgba(0, 0, 0, 0.1);

    /* Animation Tokens */
    --transition-fast: 0.2s ease;
    --transition-base: 0.3s ease;
    --transition-smooth: 0.5s cubic-bezier(0.4, 0, 0.2, 1);
}

/* Dark Mode Variables */
[data-theme="dark"] {
    --primary-navy: #E0E7FF;
    --accent-blue: #60A5FA;
    --accent-blue-dark: #3B82F6;
    --highlight-teal: #2DD4BF;
    --light-bg: #111827;
    --white: #1F2937;
    --text-dark: #F9FAFB;
    --text-mid: #E5E7EB;
    --text-light: #9CA3AF;
    --border-light: #374151;
    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.3);
    --shadow-lg: 0 10px 25px rgba(0, 0, 0, 0.4);
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    line-height: 1.6;
    color: var(--text-dark);
    background: var(--white);
    transition: background-color var(--transition-base), color var(--transition-base);
}

h1,
h2,
h3,
h4,
.nav-brand {
    font-family: 'Outfit', sans-serif;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
}

/* Navigation */
.navbar {
    background: var(--white);
    border-bottom: 1px solid var(--border-light);
    position: sticky;
    top: 0;
    z-index: 1000;
    box-shadow: var(--shadow-sm);
}

.navbar .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding-top: 1rem;
    padding-bottom: 1rem;
}

.nav-brand {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-navy);
    letter-spacing: -0.02em;
}

.nav-toggle {
    display: none;
    flex-direction: column;
    gap: 4px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 8px;
}

.nav-toggle span {
    display: block;
    width: 24px;
    height: 2px;
    background: var(--primary-navy);
    transition: all 0.3s;
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 2.5rem;
    margin: 0;
}

.nav-menu a {
    color: var(--text-mid);
    text-decoration: none;
    font-weight: 500;
    font-size: 0.95rem;
    transition: color 0.3s;
    position: relative;
}

.nav-menu a::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--accent-blue);
    transition: width 0.3s;
}

.nav-menu a:hover {
    color: var(--accent-blue);
}

.nav-menu a:hover::after {
    width: 100%;
}

/* Theme Toggle */
.theme-toggle {
    background: none;
    border: none;
    color: var(--text-mid);
    cursor: pointer;
    padding: 8px;
    border-radius: 50%;
    transition: all var(--transition-base);
    display: flex;
    align-items: center;
    justify-content: center;
}

.theme-toggle:hover {
    background: var(--light-bg);
    color: var(--accent-blue);
}

.theme-toggle svg {
    width: 20px;
    height: 20px;
}

.sun-icon {
    display: none;
}

.moon-icon {
    display: block;
}

[data-theme="dark"] .sun-icon {
    display: block;
}

[data-theme="dark"] .moon-icon {
    display: none;
}

/* Hero Section */
.hero {
    background: linear-gradient(135deg, var(--light-bg) 0%, var(--white) 100%);
    padding: 7rem 0 5rem;
}

.hero-content {
    display: grid;
    grid-template-columns: 1.3fr 1fr;
    gap: 4rem;
    align-items: start;
}

.hero-kicker {
    color: var(--accent-blue);
    font-weight: 600;
    font-size: 0.95rem;
    letter-spacing: 0.05em;
    text-transform: uppercase;
    margin-bottom: 1rem;
}

.hero-text h1 {
    font-size: 3.5rem;
    color: var(--primary-navy);
    margin-bottom: 1.5rem;
    line-height: 1.1;
    font-weight: 800;
    letter-spacing: -0.03em;
}

.hero-intro {
    font-size: 1.25rem;
    color: var(--text-mid);
    margin-bottom: 1rem;
    line-height: 1.6;
    font-weight: 500;
}

.hero-description {
    font-size: 1.05rem;
    color: var(--text-light);
    margin-bottom: 2rem;
    line-height: 1.7;
}

.hero-cta {
    display: flex;
    gap: 1rem;
    margin-top: 2rem;
}

.btn {
    padding: 0.875rem 2rem;
    text-decoration: none;
    border-radius: 6px;
    font-weight: 600;
    font-size: 0.95rem;
    transition: all 0.3s;
    display: inline-block;
    border: none;
    cursor: pointer;
}

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

.btn-primary:hover {
    background: #2557E8;
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.btn-secondary {
    background: transparent;
    color: var(--accent-blue);
    border: 2px solid var(--accent-blue);
}

.btn-secondary:hover {
    background: var(--accent-blue);
    color: var(--white);
}

/* Profile Section */
.hero-image {
    display: flex;
    flex-direction: column;
    align-items: center;
}

.profile-photo {
    width: 280px;
    height: 280px;
    border-radius: 50%;
    object-fit: cover;
    border: 4px solid var(--white);
    box-shadow: var(--shadow-lg);
    margin-bottom: 1.5rem;
}

.profile-info {
    text-align: center;
}

.profile-info h3 {
    color: var(--primary-navy);
    margin-bottom: 1rem;
    font-size: 1.4rem;
    font-weight: 700;
}

.profile-credentials {
    margin-top: 1rem;
    text-align: left;
}

.profile-credentials ul {
    list-style: none;
    padding: 0;
}

.profile-credentials li {
    color: var(--text-light);
    font-size: 0.95rem;
    margin-bottom: 0.5rem;
    line-height: 1.5;
    position: relative;
    padding-left: 1.25rem;
}

.profile-credentials li::before {
    content: "•";
    position: absolute;
    left: 0;
    color: var(--accent-blue);
    font-weight: bold;
}

.social-links {
    display: flex;
    gap: 0.75rem;
    justify-content: center;
    margin-top: 1.25rem;
    flex-wrap: wrap;
}

.social-links a {
    color: var(--accent-blue);
    text-decoration: none;
    font-weight: 600;
    padding: 0.5rem 1rem;
    border: 1.5px solid var(--accent-blue);
    border-radius: 6px;
    transition: all 0.3s;
    font-size: 0.85rem;
}

.social-links a:hover {
    background: var(--accent-blue);
    color: var(--white);
}

/* Vision Section */
.vision {
    padding: 5rem 0;
    background: var(--white);
}

.vision h2 {
    font-size: 2.75rem;
    color: var(--primary-navy);
    margin-bottom: 1.5rem;
    font-weight: 800;
    text-align: center;
    letter-spacing: -0.01em;
}

/* Premium Loading Animations */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes fadeInDown {
    from {
        opacity: 0;
        transform: translateY(-20px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.reveal-item {
    opacity: 0;
    animation-fill-mode: both;
    animation-duration: 0.8s;
    animation-timing-function: cubic-bezier(0.4, 0, 0.2, 1);
}

.hero-kicker.reveal-item {
    animation-name: fadeInDown;
}

.reveal-item:not(.hero-kicker) {
    animation-name: fadeInUp;
}

.stagger-1 {
    animation-delay: 0.1s;
}

.stagger-2 {
    animation-delay: 0.2s;
}

.stagger-3 {
    animation-delay: 0.3s;
}

.stagger-4 {
    animation-delay: 0.4s;
}

.stagger-5 {
    animation-delay: 0.5s;
}

.stagger-6 {
    animation-delay: 0.6s;
}

/* Animations section remains at the bottom */
.section-lead {
    font-size: 1.25rem;
    color: var(--text-light);
    text-align: center;
    max-width: 900px;
    margin: 0 auto 4rem;
    line-height: 1.8;
}

.vision-cards {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 2rem;
    margin-top: 3rem;
}

.vision-card {
    background: var(--light-bg);
    padding: 2.5rem;
    border-radius: 12px;
    border-left: 4px solid var(--accent-blue);
    transition: transform 0.3s, box-shadow 0.3s;
}

.vision-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.card-number {
    font-size: 2.5rem;
    font-weight: 800;
    color: var(--accent-blue);
    margin-bottom: 1rem;
    opacity: 0.2;
    font-family: 'Outfit', sans-serif;
}

.vision-card h3 {
    color: var(--primary-navy);
    margin-bottom: 1rem;
    font-size: 1.4rem;
    font-weight: 700;
}

.vision-card p {
    color: var(--text-light);
    line-height: 1.7;
}

/* Research Timeline */
.research {
    padding: 5rem 0;
    background: var(--light-bg);
}

.research h2 {
    font-size: 2.75rem;
    color: var(--primary-navy);
    margin-bottom: 1.5rem;
    font-weight: 800;
    text-align: center;
    letter-spacing: -0.02em;
}

.research-timeline {
    margin-top: 4rem;
    position: relative;
}

.research-timeline::before {
    content: '';
    position: absolute;
    left: 20px;
    top: 0;
    bottom: 0;
    width: 4px;
    background: var(--accent-blue);
    opacity: 0.3;
}

.timeline-item {
    display: grid;
    grid-template-columns: 40px 1fr;
    gap: 2rem;
    margin-bottom: 3rem;
    position: relative;
}

.timeline-marker {
    position: relative;
    z-index: 1;
}

.timeline-dot {
    width: 40px;
    height: 40px;
    background: var(--accent-blue);
    border-radius: 50%;
    border: 4px solid var(--light-bg);
    position: relative;
}

.timeline-content {
    background: var(--white);
    padding: 2.5rem;
    border-radius: 12px;
    box-shadow: var(--shadow-md);
    transition: transform var(--transition-base), box-shadow var(--transition-base);
    border: 1px solid var(--border-light);
}

.timeline-content:hover {
    transform: translateX(10px);
    box-shadow: var(--shadow-lg);
}

.phase-label {
    display: inline-block;
    background: var(--highlight-teal);
    color: var(--white);
    padding: 0.25rem 0.75rem;
    border-radius: 4px;
    font-size: 0.8rem;
    font-weight: 700;
    letter-spacing: 0.05em;
    text-transform: uppercase;
    margin-bottom: 1rem;
}

.timeline-content h3 {
    color: var(--primary-navy);
    margin-bottom: 1rem;
    font-size: 1.5rem;
    font-weight: 700;
}

.timeline-content p {
    color: var(--text-light);
    line-height: 1.7;
    margin-bottom: 1.25rem;
}

.impact-box {
    background: var(--light-bg);
    padding: 1rem 1.25rem;
    border-radius: 8px;
    border-left: 3px solid var(--highlight-teal);
    margin-top: 1.25rem;
}

.impact-box strong {
    color: var(--primary-navy);
}

/* Approach Section */
.approach {
    padding: 5rem 0;
    background: var(--white);
}

.approach h2 {
    font-size: 2.75rem;
    color: var(--primary-navy);
    margin-bottom: 1.5rem;
    font-weight: 800;
    text-align: center;
    letter-spacing: -0.02em;
}

.approach-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 2rem;
    margin-top: 3rem;
}

.approach-item {
    background: var(--light-bg);
    padding: 2rem;
    border-radius: 12px;
}

.approach-item h3 {
    color: var(--primary-navy);
    margin-bottom: 1rem;
    font-size: 1.3rem;
    font-weight: 700;
}

.approach-item ul {
    list-style: none;
    padding: 0;
}

.approach-item li {
    color: var(--text-light);
    padding: 0.5rem 0;
    padding-left: 1.5rem;
    position: relative;
    line-height: 1.6;
}

.approach-item li::before {
    content: "→";
    position: absolute;
    left: 0;
    color: var(--accent-blue);
    font-weight: bold;
}

.explainability-callout {
    margin-top: 3rem;
    padding: 2.5rem;
    background: linear-gradient(135deg, var(--accent-blue) 0%, #5580FF 100%);
    border-radius: 12px;
    color: var(--white);
}

.explainability-callout h3 {
    color: var(--white);
    margin-bottom: 1rem;
    font-size: 1.5rem;
    font-weight: 700;
}

.explainability-callout p {
    line-height: 1.7;
    margin-bottom: 0.75rem;
    opacity: 0.95;
}

.explainability-callout strong {
    font-weight: 700;
}

/* Publications Section */
.publications {
    padding: 5rem 0;
    background: var(--light-bg);
}

.publications h2 {
    font-size: 2.75rem;
    color: var(--primary-navy);
    margin-bottom: 3rem;
    font-weight: 800;
    text-align: center;
    letter-spacing: -0.02em;
}

.pub-category {
    margin-bottom: 3rem;
}

.pub-category h3 {
    color: var(--primary-navy);
    font-size: 1.75rem;
    margin-bottom: 1.5rem;
    font-weight: 700;
    padding-bottom: 0.75rem;
    border-bottom: 3px solid var(--accent-blue);
}

.pub-cards {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 1.5rem;
}

.pub-card {
    background: var(--white);
    padding: 1.75rem;
    border-radius: 10px;
    box-shadow: var(--shadow-sm);
    border-left: 3px solid var(--highlight-teal);
    transition: transform 0.3s, box-shadow 0.3s;
}

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

.pub-card h4 {
    color: var(--primary-navy);
    margin-bottom: 0.5rem;
    font-size: 1.1rem;
    line-height: 1.4;
    font-weight: 600;
}

.pub-meta {
    color: var(--text-mid);
    font-size: 0.9rem;
    margin-bottom: 0.75rem;
}

.pub-desc {
    color: var(--text-light);
    line-height: 1.6;
    margin-bottom: 0.75rem;
    font-size: 0.95rem;
}

.pub-link {
    color: var(--accent-blue);
    text-decoration: none;
    font-weight: 600;
    font-size: 0.9rem;
    transition: color 0.3s;
}

.pub-link:hover {
    color: #2557E8;
}

.pub-cta {
    text-align: center;
    margin-top: 3rem;
}

/* Media Section */
.media {
    padding: 5rem 0;
    background: var(--white);
}

.media h2 {
    font-size: 2.75rem;
    color: var(--primary-navy);
    margin-bottom: 3rem;
    font-weight: 800;
    text-align: center;
    letter-spacing: -0.02em;
}

.media-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 2rem;
}

.media-card {
    background: var(--light-bg);
    padding: 2rem;
    border-radius: 12px;
    transition: transform 0.3s, box-shadow 0.3s;
}

.media-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.media-tag {
    display: inline-block;
    background: var(--highlight-teal);
    color: var(--white);
    padding: 0.25rem 0.75rem;
    border-radius: 4px;
    font-size: 0.75rem;
    font-weight: 700;
    letter-spacing: 0.05em;
    text-transform: uppercase;
    margin-bottom: 1rem;
}

.media-card h3 {
    color: var(--primary-navy);
    margin-bottom: 0.75rem;
    font-size: 1.3rem;
    font-weight: 700;
}

.media-card p {
    color: var(--text-light);
    line-height: 1.6;
    margin-bottom: 1rem;
}

.media-link {
    color: var(--accent-blue);
    text-decoration: none;
    font-weight: 600;
    transition: color 0.3s;
}

.media-link:hover {
    color: #2557E8;
}

/* Join Section */
.join {
    padding: 5rem 0;
    background: var(--light-bg);
}

.join h2 {
    font-size: 2.75rem;
    color: var(--primary-navy);
    margin-bottom: 1.5rem;
    font-weight: 800;
    text-align: center;
    letter-spacing: -0.02em;
}

.join-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 2rem;
    margin: 3rem 0;
}

.join-section {
    background: var(--white);
    padding: 2rem;
    border-radius: 12px;
    box-shadow: var(--shadow-sm);
}

.join-section h3 {
    color: var(--primary-navy);
    margin-bottom: 1.25rem;
    font-size: 1.4rem;
    font-weight: 700;
}

.join-list {
    list-style: none;
    padding: 0;
}

.join-list li {
    color: var(--text-light);
    padding: 0.75rem 0;
    padding-left: 1.5rem;
    position: relative;
    line-height: 1.5;
    border-bottom: 1px solid var(--border-light);
}

.join-list li:last-child {
    border-bottom: none;
}

.join-list li::before {
    content: "✓";
    position: absolute;
    left: 0;
    color: var(--highlight-teal);
    font-weight: bold;
}

.join-focus {
    margin: 3rem 0;
    text-align: center;
}

.join-focus h3 {
    color: var(--primary-navy);
    margin-bottom: 1.5rem;
    font-size: 1.4rem;
    font-weight: 700;
}

.focus-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 0.75rem;
    justify-content: center;
}

.focus-tag {
    background: var(--white);
    color: var(--accent-blue);
    padding: 0.5rem 1.25rem;
    border-radius: 25px;
    font-weight: 600;
    font-size: 0.9rem;
    border: 2px solid var(--accent-blue);
    transition: all 0.3s;
}

.focus-tag:hover {
    background: var(--accent-blue);
    color: var(--white);
}

.join-cta {
    text-align: center;
    margin-top: 3rem;
    padding: 2.5rem;
    background: var(--white);
    border-radius: 12px;
}

.join-cta p {
    font-size: 1.1rem;
    color: var(--text-mid);
    margin-bottom: 1.5rem;
}

/* Footer */
.footer {
    background: var(--primary-navy);
    color: var(--white);
    padding: 3rem 0 1.5rem;
}

.footer-content {
    display: grid;
    grid-template-columns: 1.5fr 1fr;
    gap: 3rem;
    padding-bottom: 2rem;
    border-bottom: 1px solid rgba(255, 255, 255, 0.2);
    margin-bottom: 1.5rem;
}

.footer-bio h3 {
    margin-bottom: 0.75rem;
    font-size: 1.5rem;
    font-weight: 700;
}

.footer-bio p {
    opacity: 0.9;
    margin-bottom: 0.5rem;
    line-height: 1.6;
}

.footer-note {
    margin-top: 1rem;
    font-size: 0.9rem;
    opacity: 0.8;
}

/* Back to Top */
.back-to-top {
    position: fixed;
    bottom: 30px;
    right: 30px;
    width: 50px;
    height: 50px;
    background: var(--accent-blue);
    color: var(--white);
    border: none;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    box-shadow: var(--shadow-lg);
    opacity: 0;
    visibility: hidden;
    transition: all var(--transition-base);
    z-index: 1000;
}

.back-to-top.visible {
    opacity: 1;
    visibility: visible;
}

.back-to-top:hover {
    background: var(--accent-blue-dark);
    transform: translateY(-5px);
}

.back-to-top svg {
    width: 24px;
    height: 24px;
}

/* Animations */
.reveal-item {
    opacity: 0;
    transform: translateY(30px);
    transition: opacity var(--transition-smooth), transform var(--transition-smooth);
}

.fade-in {
    opacity: 1;
    transform: translateY(0);
}

/* Base Responsive Fixes */
@media (max-width: 768px) {
    .hero-content {
        grid-template-columns: 1fr;
        text-align: center;
    }

    .hero-image {
        order: -1;
        margin-bottom: 2rem;
    }

    .nav-toggle {
        display: flex;
    }

    .nav-menu {
        position: fixed;
        top: 70px;
        left: -100%;
        width: 100%;
        height: calc(100vh - 70px);
        background: var(--white);
        flex-direction: column;
        align-items: center;
        padding-top: 2rem;
        transition: left var(--transition-base);
        box-shadow: var(--shadow-md);
    }

    .nav-menu.active {
        left: 0;
    }

    .vision-cards,
    .approach-grid,
    .pub-cards,
    .media-grid,
    .join-grid {
        grid-template-columns: 1fr;
    }

    .hero-text h1 {
        font-size: 2.5rem;
    }
}

.footer-links {
    display: flex;
    gap: 1.5rem;
    align-items: center;
    justify-content: flex-end;
}

.footer-links a {
    color: var(--white);
    text-decoration: none;
    opacity: 0.85;
    font-weight: 500;
    transition: opacity 0.3s;
}

.footer-links a:hover {
    opacity: 1;
}

.footer-copyright {
    text-align: center;
    opacity: 0.6;
    font-size: 0.9rem;
}

/* Responsive Design */
@media (max-width: 968px) {
    .hero-content {
        grid-template-columns: 1fr;
        text-align: center;
    }

    .hero-text h1 {
        font-size: 2.75rem;
    }

    .hero-cta {
        justify-content: center;
        flex-wrap: wrap;
    }

    .vision-cards {
        grid-template-columns: 1fr;
    }

    .research-timeline::before {
        display: none;
    }

    .timeline-item {
        grid-template-columns: 1fr;
    }

    .timeline-marker {
        display: none;
    }

    .approach-grid {
        grid-template-columns: 1fr;
    }

    .pub-cards {
        grid-template-columns: 1fr;
    }

    .media-grid {
        grid-template-columns: 1fr;
    }

    .join-grid {
        grid-template-columns: 1fr;
    }

    .footer-content {
        grid-template-columns: 1fr;
        text-align: center;
    }

    .footer-links {
        justify-content: center;
    }

    .nav-toggle {
        display: flex;
    }

    .nav-menu {
        display: none;
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        background: var(--white);
        flex-direction: column;
        padding: 1rem;
        box-shadow: var(--shadow-md);
        gap: 0;
    }

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

    .nav-menu li {
        padding: 0.75rem 0;
        border-bottom: 1px solid var(--border-light);
    }

    .nav-menu li:last-child {
        border-bottom: none;
    }
}

@media (max-width: 640px) {
    .hero-text h1 {
        font-size: 2.25rem;
    }

    .hero-intro {
        font-size: 1.1rem;
    }

    .profile-photo {
        width: 220px;
        height: 220px;
    }

    h2 {
        font-size: 2.25rem;
    }

    .social-links {
        flex-direction: column;
        gap: 0.5rem;
    }

    .social-links a {
        width: 100%;
        text-align: center;
    }
}

.explainability-large {
    max-width: 900px;
    margin: 2.5rem auto;
    padding: 2.5rem;
    border-left-width: 6px;
    /* slightly thicker accent */
}

.explainability-large h3 {
    font-size: 1.6rem;
    /* slightly larger */
    margin-bottom: 1rem;
}

.explainability-large p {
    font-size: 1.05rem;
    line-height: 1.7;
    margin-bottom: 1rem;
}

/* Impact Highlighting */
.impact-highlight {
    color: var(--accent-blue);
    font-weight: 800;
}

.approach-item li strong {
    color: var(--primary-navy);
}

.vision-card h3 {
    letter-spacing: -0.01em;
}