:root {
    --ink: #101936;
    --ink-soft: #33405f;
    --primary: #5356df;
    --primary-dark: #3437ab;
    --accent: #31d2c0;
    --surface: #f5f7fc;
    --border: rgba(16, 25, 54, .11);
    --shadow: 0 24px 60px rgba(30, 38, 80, .12);
}

html { scroll-behavior: smooth; }
body {
    font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
    color: var(--ink);
    background: #fff;
}
a { text-decoration: none; }
.section-padding { padding: 7rem 0; }
.section-kicker {
    color: var(--primary);
    font-size: .78rem;
    font-weight: 800;
    letter-spacing: .16em;
    text-transform: uppercase;
    margin-bottom: 1rem;
}
.section-title {
    font-size: clamp(2rem, 4vw, 3.45rem);
    font-weight: 800;
    letter-spacing: -.04em;
    line-height: 1.05;
}
.section-heading-center { max-width: 780px; }

.glass-nav {
    background: rgba(12, 19, 45, .82);
    backdrop-filter: blur(18px);
    border-bottom: 1px solid rgba(255,255,255,.08);
    transition: .25s ease;
}
.glass-nav.scrolled { background: rgba(12, 19, 45, .96); }
.brand-mark {
    display: inline-grid;
    place-items: center;
    width: 38px;
    height: 38px;
    margin-right: .55rem;
    border-radius: 12px;
    background: linear-gradient(135deg, var(--accent), var(--primary));
    box-shadow: 0 8px 22px rgba(83, 86, 223, .3);
}
.navbar .nav-link { color: rgba(255,255,255,.72); font-weight: 600; font-size: .93rem; }
.navbar .nav-link:hover { color: #fff; }
.language-select {
    color: #fff;
    background-color: rgba(255,255,255,.08);
    border-color: rgba(255,255,255,.18);
    min-width: 70px;
}
.language-select option { color: #111; }

.hero-section {
    min-height: 100vh;
    position: relative;
    overflow: hidden;
    padding: 9rem 0 5rem;
    color: #fff;
    background:
        linear-gradient(120deg, rgba(10,17,42,.98), rgba(28,31,78,.95)),
        radial-gradient(circle at 80% 10%, #595cde 0, transparent 45%);
}
.hero-section::before {
    content: "";
    position: absolute;
    inset: 0;
    opacity: .18;
    background-image: linear-gradient(rgba(255,255,255,.08) 1px, transparent 1px), linear-gradient(90deg, rgba(255,255,255,.08) 1px, transparent 1px);
    background-size: 48px 48px;
    mask-image: linear-gradient(to bottom, #000 20%, transparent 85%);
}
.hero-orb { position: absolute; border-radius: 999px; filter: blur(2px); opacity: .28; }
.hero-orb-one { width: 420px; height: 420px; background: #5157e8; right: -140px; top: 80px; }
.hero-orb-two { width: 280px; height: 280px; background: #22d3bd; left: -160px; bottom: 60px; }
.eyebrow {
    display: inline-flex;
    padding: .55rem .9rem;
    border: 1px solid rgba(255,255,255,.17);
    border-radius: 999px;
    background: rgba(255,255,255,.07);
    font-weight: 700;
    color: #b7fff7;
}
.hero-headline { font-size: clamp(1.2rem, 2.1vw, 1.72rem); line-height: 1.45; color: #dce1ff; max-width: 780px; }
.hero-bio { max-width: 760px; color: rgba(255,255,255,.68); font-size: 1.05rem; line-height: 1.75; }
.hero-meta { display: flex; flex-wrap: wrap; gap: 1rem; color: rgba(255,255,255,.72); }
.hero-meta span { display: inline-flex; align-items: center; gap: .5rem; }
.btn-primary { --bs-btn-bg: var(--primary); --bs-btn-border-color: var(--primary); --bs-btn-hover-bg: var(--primary-dark); --bs-btn-hover-border-color: var(--primary-dark); }

.portrait-shell { position: relative; width: min(100%, 430px); }
.portrait-frame {
    position: relative;
    overflow: hidden;
    aspect-ratio: .82;
    border-radius: 48px 48px 160px 48px;
    padding: 10px;
    background: linear-gradient(145deg, rgba(255,255,255,.55), rgba(255,255,255,.08));
    box-shadow: 0 35px 90px rgba(0,0,0,.35);
}
.profile-photo { width: 100%; height: 100%; object-fit: cover; border-radius: 40px 40px 150px 40px; display: none; }
.portrait-placeholder { width: 100%; height: 100%; display: grid; place-items: center; border-radius: 40px 40px 150px 40px; background: linear-gradient(145deg, #30356f, #101936); }
.portrait-placeholder span { font-size: 7rem; font-weight: 900; color: rgba(255,255,255,.88); }
.floating-card {
    position: absolute;
    z-index: 2;
    display: flex;
    align-items: center;
    gap: .6rem;
    padding: .8rem 1rem;
    background: rgba(255,255,255,.92);
    color: var(--ink);
    border-radius: 16px;
    font-size: .88rem;
    font-weight: 800;
    box-shadow: 0 18px 45px rgba(0,0,0,.23);
}
.floating-card i { color: var(--primary); font-size: 1.25rem; }
.card-one { top: 12%; left: -30px; }
.card-two { right: -25px; top: 47%; }
.card-three { left: 4%; bottom: -15px; }

.stats-strip { position: relative; z-index: 3; margin-top: -42px; }
.stat-card {
    height: 100%;
    padding: 1.45rem;
    border-radius: 22px;
    background: #fff;
    border: 1px solid var(--border);
    box-shadow: var(--shadow);
}
.stat-number { font-size: 2rem; font-weight: 900; color: var(--primary); }
.stat-label { color: #6d7692; font-weight: 650; }

.research-section { background: #101936; color: #fff; }
.research-intro { top: 120px; }
.skill-card {
    height: 100%;
    padding: 1.5rem;
    border: 1px solid rgba(255,255,255,.1);
    border-radius: 22px;
    background: linear-gradient(145deg, rgba(255,255,255,.09), rgba(255,255,255,.04));
    transition: .25s ease;
}
.skill-card:hover { transform: translateY(-4px); border-color: rgba(49,210,192,.4); }
.skill-card h3 { font-size: 1rem; color: #9cf5eb; margin-bottom: 1rem; }
.skill-tags { display: flex; flex-wrap: wrap; gap: .5rem; }
.skill-tag { padding: .48rem .7rem; border-radius: 999px; background: rgba(255,255,255,.08); color: rgba(255,255,255,.82); font-size: .82rem; }

.publication-card {
    padding: 1.55rem;
    border: 1px solid var(--border);
    background: #fff;
    border-radius: 22px;
    transition: .2s ease;
}
.publication-card:hover { transform: translateY(-3px); box-shadow: var(--shadow); }
.publication-year { min-width: 72px; height: 72px; display: grid; place-items: center; border-radius: 18px; background: #eef0ff; color: var(--primary); font-weight: 900; }
.publication-title { font-size: 1.08rem; font-weight: 800; line-height: 1.45; }
.publication-authors { color: #6f7893; font-size: .9rem; }
.publication-journal { color: var(--ink-soft); font-weight: 650; }

.timeline { position: relative; max-width: 940px; margin: 0 auto; }
.timeline::before { content: ""; position: absolute; left: 17px; top: 0; bottom: 0; width: 2px; background: #dfe3f4; }
.timeline-item { position: relative; padding-left: 58px; padding-bottom: 2.1rem; }
.timeline-dot { position: absolute; left: 8px; top: 8px; width: 20px; height: 20px; border-radius: 50%; background: #fff; border: 5px solid var(--primary); box-shadow: 0 0 0 6px #eef0ff; }
.timeline-card { padding: 1.5rem; border: 1px solid var(--border); border-radius: 20px; background: #fff; }
.timeline-role { font-size: 1.2rem; font-weight: 850; }
.timeline-meta { color: #6f7893; }

.articles-section { background: #f6f8fe; }
.article-card { height: 100%; overflow: hidden; border: 1px solid var(--border); border-radius: 24px; background: #fff; transition: .25s ease; }
.article-card:hover { transform: translateY(-6px); box-shadow: var(--shadow); }
.article-cover { width: 100%; aspect-ratio: 16/9; object-fit: cover; background: linear-gradient(135deg, #202860, #4f55dc); }
.article-cover-placeholder { display: grid; place-items: center; color: rgba(255,255,255,.92); font-size: 3rem; }
.article-content { padding: 1.35rem; }
.article-title { font-size: 1.15rem; line-height: 1.4; font-weight: 850; }
.article-excerpt { color: #6d7692; line-height: 1.65; }
.article-filters .btn { font-weight: 700; }

.contact-section { background: linear-gradient(130deg, #0d1533, #1e2458); }
.contact-card { padding: clamp(1.4rem, 4vw, 2.4rem); border-radius: 28px; background: #fff; box-shadow: 0 35px 80px rgba(0,0,0,.25); }
.contact-card .form-control { min-height: 52px; border-radius: 14px; border-color: #dfe3ef; }
.contact-card textarea.form-control { min-height: 150px; }
.contact-details a, .contact-details div { color: rgba(255,255,255,.78); display: flex; align-items: flex-start; gap: .75rem; margin-bottom: 1rem; }
.contact-details i { color: var(--accent); font-size: 1.2rem; }
.site-footer { background: #080d20; color: rgba(255,255,255,.62); }
.footer-admin-link { color: rgba(255,255,255,.55); }
.footer-admin-link:hover { color: #fff; }

.article-modal-close { position: absolute; top: 1.1rem; right: 1.1rem; z-index: 5; padding: .75rem; background-color: #fff; border-radius: 999px; }
.article-modal-image { width: 100%; max-height: 520px; object-fit: cover; }
.article-body { color: #3f4965; line-height: 1.85; font-size: 1.03rem; }
.article-body h2, .article-body h3 { color: var(--ink); margin-top: 1.7rem; }
.article-gallery-image { width: 100%; aspect-ratio: 4/3; object-fit: cover; border-radius: 18px; }
.loading-overlay { position: fixed; inset: 0; z-index: 2000; display: grid; place-items: center; background: rgba(255,255,255,.9); transition: opacity .25s; }
.loading-overlay.hidden { opacity: 0; pointer-events: none; }
.empty-state { padding: 3rem; text-align: center; border: 1px dashed #cfd5e8; border-radius: 22px; color: #78809a; }

@media (max-width: 991.98px) {
    .section-padding { padding: 5rem 0; }
    .hero-section { min-height: auto; }
    .navbar-collapse { padding: 1rem 0; }
    .portrait-shell { margin-top: 1rem; }
    .card-one { left: -5px; }
    .card-two { right: -5px; }
    .research-intro { position: static !important; }
}
@media (max-width: 575.98px) {
    .hero-section { padding-top: 7rem; }
    .portrait-frame { border-radius: 30px 30px 90px 30px; }
    .portrait-placeholder, .profile-photo { border-radius: 23px 23px 82px 23px; }
    .floating-card { position: static; display: inline-flex; margin: .8rem .35rem 0 0; }
    .portrait-shell { text-align: center; }
    .stats-strip { margin-top: -18px; }
    .publication-year { min-width: 58px; height: 58px; }
}