:root {
    --bg: #f7f7f9;
    --surface: #ffffff;
    --text: #0b0d16;
    --muted: #5a6072;
    --accent: #1f6feb;
    --accent-strong: #0f3c96;
    --border: #e1e4eb;
    --shadow: 0 20px 60px rgba(15, 30, 80, 0.08);
    font-size: 16px;
}

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

body {
    margin: 0;
    font-family: "Inter", "Segoe UI", Roboto, system-ui, -apple-system, sans-serif;
    color: var(--text);
    background: var(--bg);
    line-height: 1.6;
}

.skip-link {
    position: absolute;
    top: -40px;
    left: 12px;
    background: var(--accent);
    color: #fff;
    padding: 0.5rem 1rem;
    border-radius: 999px;
    text-decoration: none;
    transition: top 0.2s ease;
    z-index: 2000;
}

.skip-link:focus {
    top: 12px;
}

.site-header {
    position: sticky;
    top: 0;
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 1rem 4vw;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(12px);
    border-bottom: 1px solid rgba(225, 228, 235, 0.7);
    z-index: 1000;
}

.site-header.is-scrolled {
    box-shadow: 0 10px 40px rgba(15, 25, 55, 0.08);
}

.brand {
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.brand-mark {
    width: 44px;
    height: 44px;
    border-radius: 12px;
    background: var(--text);
    color: #fff;
    font-weight: 600;
    display: grid;
    place-items: center;
}

.brand-name {
    margin: 0;
    font-size: 1rem;
    font-weight: 600;
}

.brand-role {
    margin: 0;
    color: var(--muted);
    font-size: 0.9rem;
}

.site-nav ul {
    list-style: none;
    display: flex;
    gap: 1.5rem;
    margin: 0;
    padding: 0;
}

.site-nav a {
    color: var(--text);
    text-decoration: none;
    font-weight: 500;
    font-size: 0.95rem;
    position: relative;
}

.site-nav a::after {
    content: "";
    position: absolute;
    left: 0;
    bottom: -4px;
    width: 100%;
    height: 2px;
    background: var(--accent);
    transform: scaleX(0);
    transform-origin: left;
    transition: transform 0.2s ease;
}

.site-nav a:focus-visible,
.site-nav a:hover {
    color: var(--accent);
}

.site-nav a:hover::after,
.site-nav a:focus-visible::after {
    transform: scaleX(1);
}

.nav-toggle {
    display: none;
    align-items: center;
    justify-content: center;
    gap: 4px;
    width: 44px;
    height: 44px;
    border-radius: 50%;
    border: 1px solid rgba(15, 15, 30, 0.15);
    background: #fff;
    cursor: pointer;
}

.nav-toggle .dot {
    width: 6px;
    height: 6px;
    border-radius: 50%;
    background: var(--text);
}

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

main {
    padding: 4rem 4vw 5rem;
    max-width: 1200px;
    margin: 0 auto;
}

.hero {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 2.5rem;
    background: var(--surface);
    border-radius: 28px;
    padding: 3rem;
    box-shadow: var(--shadow);
    margin-bottom: 3rem;
}

.hero,
.section,
.publication-subsection {
    scroll-margin-top: 110px;
}

.hero h1 {
    margin-top: 0.3rem;
    font-size: clamp(2rem, 4vw, 3.2rem);
    line-height: 1.2;
}

.eyebrow {
    text-transform: uppercase;
    letter-spacing: 0.2em;
    font-size: 0.78rem;
    color: var(--muted);
    margin: 0;
}

.lead {
    font-size: 1.05rem;
    color: var(--muted);
}

.contact-list {
    list-style: none;
    padding: 0;
    margin: 1.25rem 0;
    display: grid;
    gap: 0.4rem;
}

.contact-list strong {
    font-weight: 600;
    color: var(--text);
}

.hero-actions {
    display: flex;
    flex-wrap: wrap;
    gap: 1rem;
    margin-top: 1.5rem;
}

.btn {
    text-decoration: none;
    font-weight: 600;
    padding: 0.85rem 1.6rem;
    border-radius: 999px;
    border: 1px solid transparent;
    transition: all 0.2s ease;
}

.btn.primary {
    background: var(--text);
    color: #fff;
}

.btn.primary:hover,
.btn.primary:focus-visible {
    background: var(--accent-strong);
}

.btn.ghost {
    border-color: var(--border);
    color: var(--text);
}

.btn.ghost:hover,
.btn.ghost:focus-visible {
    border-color: var(--accent);
    color: var(--accent);
}

.hero-portrait {
    margin: 0;
    text-align: center;
}

.hero-portrait img {
    width: min(320px, 100%);
    border-radius: 24px;
    box-shadow: var(--shadow);
}

.hero-portrait figcaption {
    margin-top: 0.75rem;
    font-size: 0.85rem;
    color: var(--muted);
}

.section {
    background: var(--surface);
    border-radius: 28px;
    padding: 2.5rem;
    margin-bottom: 2.5rem;
    box-shadow: 0 18px 40px rgba(20, 35, 90, 0.05);
}

.section-heading h2 {
    margin: 0.35rem 0 1.5rem;
    font-size: 1.9rem;
}

.subtabs {
    display: inline-flex;
    gap: 0.5rem;
    padding: 0.25rem;
    border-radius: 999px;
    border: 1px solid var(--border);
    background: #fdfdff;
    margin-bottom: 1.75rem;
}

.subtab {
    border: none;
    border-radius: 999px;
    padding: 0.5rem 1.25rem;
    font-weight: 600;
    text-decoration: none;
    color: var(--muted);
    transition: background 0.2s ease, color 0.2s ease;
}

.subtab.is-active {
    background: var(--text);
    color: #fff;
    box-shadow: 0 8px 20px rgba(15, 20, 40, 0.15);
}

.subtab:hover,
.subtab:focus-visible {
    color: var(--accent);
}

.publication-groups {
    display: grid;
    gap: 1.5rem;
}

.publication-subsection {
    border: 1px solid var(--border);
    border-radius: 18px;
    padding: 1.75rem;
    background: #fff;
}

.publication-subsection:target {
    border-color: var(--accent);
    box-shadow: 0 10px 30px rgba(31, 111, 235, 0.15);
}

.stat-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
    gap: 1.5rem;
}

.stat-grid article {
    padding: 1.5rem;
    border: 1px solid var(--border);
    border-radius: 18px;
}

.stat-value {
    font-size: 2rem;
    font-weight: 600;
    margin: 0 0 0.5rem;
}

.stat-label {
    margin: 0;
    color: var(--muted);
}

.chip-list {
    display: flex;
    flex-wrap: wrap;
    gap: 0.75rem;
}

.chip {
    border: 1px solid var(--border);
    border-radius: 999px;
    padding: 0.45rem 1.1rem;
    font-size: 0.95rem;
    background: #fcfcff;
}

.timeline {
    list-style: none;
    margin: 0;
    padding: 0;
    display: grid;
    gap: 1.8rem;
    position: relative;
}

.timeline::before {
    content: "";
    position: absolute;
    left: 12px;
    top: 4px;
    bottom: 4px;
    width: 2px;
    background: var(--border);
}

.timeline li {
    padding-left: 2.5rem;
    position: relative;
}

.timeline-marker {
    width: 14px;
    height: 14px;
    border-radius: 50%;
    background: var(--accent);
    position: absolute;
    left: 6px;
    top: 6px;
}

.timeline-date {
    margin: 0;
    color: var(--muted);
    font-size: 0.95rem;
}

.card-stack {
    display: grid;
    gap: 1.5rem;
}

.card {
    border: 1px solid var(--border);
    border-radius: 18px;
    padding: 1.75rem;
}

.card-date {
    margin: 0;
    font-size: 0.9rem;
    color: var(--muted);
}

.note {
    margin-top: 1.5rem;
    color: var(--muted);
}

.patent-list {
    margin: 0;
    padding-left: 1.2rem;
    display: grid;
    gap: 1rem;
}

.patent-list h3 {
    margin: 0;
}

.achievement-list {
    margin: 0;
    padding-left: 1.2rem;
    display: grid;
    gap: 0.8rem;
}

.contact {
    background: radial-gradient(circle at top, rgba(31, 111, 235, 0.07), transparent 60%), var(--surface);
}

.contact-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
    gap: 2rem;
    align-items: start;
}

.contact-form {
    display: grid;
    gap: 0.75rem;
}

.contact-form input,
.contact-form textarea {
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 0.75rem;
    font: inherit;
    background: #fff;
    transition: border 0.2s ease;
}

.contact-form input:focus,
.contact-form textarea:focus {
    outline: none;
    border-color: var(--accent);
}

.contact-form button {
    border: none;
    border-radius: 999px;
    padding: 0.9rem 1.2rem;
    background: var(--accent);
    color: #fff;
    font-weight: 600;
    cursor: pointer;
    transition: background 0.2s ease;
}

.contact-form button:hover,
.contact-form button:focus-visible {
    background: var(--accent-strong);
}

.social-links {
    display: inline-flex;
    flex-wrap: wrap;
    gap: 0.75rem;
    margin-top: 1rem;
}

.social-links a {
    text-decoration: none;
    font-weight: 600;
    color: var(--accent-strong);
    border-bottom: 1px solid transparent;
    transition: border-color 0.2s ease;
}

.social-links a:hover,
.social-links a:focus-visible {
    border-color: currentColor;
}

.site-footer {
    text-align: center;
    padding: 2rem 0 3rem;
    color: var(--muted);
}

@media (max-width: 900px) {
    .site-nav {
        position: absolute;
        top: calc(100% + 0.5rem);
        right: 4vw;
        background: #fff;
        border: 1px solid var(--border);
        border-radius: 16px;
        box-shadow: var(--shadow);
        padding: 1rem 1.25rem;
        transform: scale(0.95);
        transform-origin: top right;
        opacity: 0;
        pointer-events: none;
        transition: opacity 0.2s ease, transform 0.2s ease;
    }

    .site-nav ul {
        flex-direction: column;
        gap: 0.75rem;
    }

    .site-nav.is-open {
        opacity: 1;
        transform: scale(1);
        pointer-events: auto;
    }

    .nav-toggle {
        display: inline-flex;
    }
}

@media (max-width: 640px) {
    .site-header {
        padding: 0.8rem 1rem;
    }

    main {
        padding: 3rem 1rem 4rem;
    }

    .hero,
    .section {
        padding: 2rem;
    }
}