/* Base */
:root {
    --font-heading: 'Space Grotesk', 'Manrope', system-ui, -apple-system, sans-serif;
    --font-body: 'Manrope', system-ui, -apple-system, sans-serif;
    --bg: #f5f7fb;
    --bg-accent: radial-gradient(circle at 20% 20%, rgba(14, 165, 233, 0.12), transparent 35%),
                 radial-gradient(circle at 80% 0%, rgba(245, 158, 11, 0.14), transparent 30%),
                 #f5f7fb;
    --surface: #ffffff;
    --panel: #0f172a;
    --text: #0f172a;
    --muted: #5b6477;
    --accent: #0ea5e9;
    --accent-2: #f59e0b;
    --pill: #e2f3ff;
    --shadow: 0 25px 60px rgba(15, 23, 42, 0.12);
    --radius: 18px;
}

body.dark-mode {
    --bg: #050912;
    --bg-accent: radial-gradient(circle at 20% 20%, rgba(14, 165, 233, 0.1), transparent 35%),
                 radial-gradient(circle at 80% 0%, rgba(245, 158, 11, 0.12), transparent 30%),
                 #050912;
    --surface: #0c162c;
    --panel: #0b1021;
    --text: #e2e8f0;
    --muted: #94a3b8;
    --accent: #38bdf8;
    --accent-2: #fbbf24;
    --pill: rgba(56, 189, 248, 0.12);
    --shadow: 0 25px 60px rgba(0, 0, 0, 0.45);
}

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

body {
    font-family: var(--font-body);
    line-height: 1.7;
    color: var(--text);
    background: var(--bg-accent);
    padding-top: 76px;
    transition: background 0.4s ease, color 0.4s ease;
}

img {
    max-width: 100%;
    display: block;
}

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

.container.narrow {
    max-width: 960px;
}

/* Navigation */
#navbar {
    position: fixed;
    top: 0;
    width: 100%;
    z-index: 1000;
    background: rgba(255, 255, 255, 0.72);
    backdrop-filter: blur(14px);
    border-bottom: 1px solid rgba(15, 23, 42, 0.05);
    transition: background 0.3s ease, border-color 0.3s ease;
}

body.dark-mode #navbar {
    background: rgba(12, 22, 44, 0.82);
    border-color: rgba(255, 255, 255, 0.06);
}

.nav-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 16px 0;
}

.nav-logo {
    font-family: var(--font-heading);
    font-weight: 700;
    font-size: 1.25rem;
    letter-spacing: 1px;
    color: var(--text);
}

.nav-menu {
    display: flex;
    list-style: none;
    align-items: center;
    gap: 18px;
}

.nav-menu li {
    position: relative;
}

.nav-close {
    display: none;
}

.nav-link {
    text-decoration: none;
    color: var(--muted);
    font-weight: 600;
    letter-spacing: 0.01em;
    transition: color 0.25s ease;
}

.nav-link::after {
    content: '';
    position: absolute;
    left: 0;
    bottom: -8px;
    width: 0;
    height: 2px;
    background: linear-gradient(90deg, var(--accent), var(--accent-2));
    transition: width 0.25s ease;
}

.nav-link:hover,
.nav-link.active {
    color: var(--text);
}

.nav-link:hover::after,
.nav-link.active::after {
    width: 100%;
}

.nav-actions {
    display: flex;
    align-items: center;
    gap: 12px;
}

.nav-toggle {
    display: none;
    cursor: pointer;
    color: var(--text);
    font-size: 1.3rem;
    transition: transform 0.25s ease;
}

.nav-toggle i {
    transition: transform 0.25s ease;
}

.nav-toggle.open i {
    transform: rotate(90deg);
}

.dark-mode-toggle {
    background: var(--pill);
    border: 1px solid rgba(15, 23, 42, 0.08);
    border-radius: 999px;
    color: var(--text);
    width: 42px;
    height: 42px;
    display: grid;
    place-items: center;
    cursor: pointer;
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.dark-mode-toggle:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow);
}

/* Hero */
.hero {
    position: relative;
    overflow: hidden;
    background: linear-gradient(135deg, rgba(14, 165, 233, 0.16), rgba(21, 36, 74, 0.7)), var(--bg);
    color: #fff;
    min-height: 90vh;
    display: flex;
    align-items: center;
}

.hero-overlay {
    position: absolute;
    inset: 0;
    background: radial-gradient(circle at 30% 20%, rgba(255, 255, 255, 0.08), transparent 40%),
                radial-gradient(circle at 80% 10%, rgba(245, 158, 11, 0.08), transparent 35%);
    pointer-events: none;
    z-index: 1;
}

.hero-grid {
    position: relative;
    z-index: 2;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 32px;
    align-items: center;
    padding: 110px 0 90px;
}

.hero-content {
    display: grid;
    gap: 18px;
    color: var(--text);
}

.eyebrow {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 8px 14px;
    border-radius: 999px;
    background: rgba(14, 165, 233, 0.18);
    color: var(--text);
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.06em;
    font-size: 0.8rem;
}

.hero .eyebrow {
    background: rgba(255, 255, 255, 0.8);
    color: #0f172a;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.08);
}

.hero-title {
    font-family: var(--font-heading);
    font-size: clamp(2.6rem, 4vw, 3.6rem);
    line-height: 1.15;
    color: #0b1224;
    text-shadow: 0 10px 30px rgba(0, 0, 0, 0.12);
}

.hero-title .highlight {
    color: var(--accent-2);
}

.hero-lead {
    font-size: 1.1rem;
    color: #0f172a;
    max-width: 680px;
    text-shadow: 0 8px 30px rgba(0, 0, 0, 0.12);
}

.hero-tags,
.pill-row {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
}

.pill {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 10px 14px;
    border-radius: 999px;
    background: var(--pill);
    color: var(--text);
    font-weight: 600;
    font-size: 0.95rem;
}

.hero-actions {
    display: flex;
    flex-wrap: wrap;
    gap: 12px;
    align-items: center;
}

.btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    border-radius: 12px;
    padding: 12px 16px;
    border: 1px solid transparent;
    text-decoration: none;
    font-weight: 700;
    letter-spacing: 0.01em;
    transition: transform 0.2s ease, box-shadow 0.25s ease, background 0.25s ease, color 0.25s ease;
}

.btn:hover {
    transform: translateY(-2px);
}

.btn.primary {
    background: #fff;
    color: #0f172a;
    box-shadow: var(--shadow);
}

.btn.ghost {
    background: rgba(255, 255, 255, 0.08);
    color: #e5edff;
    border-color: rgba(255, 255, 255, 0.15);
}

.btn.ghost:hover {
    background: #fff;
    color: #0f172a;
    box-shadow: var(--shadow);
    border-color: transparent;
}

.btn.accent {
    position: relative;
    overflow: hidden;
    background: linear-gradient(120deg, var(--accent), var(--accent-2));
    background-size: 200% 200%;
    color: #0f172a;
    box-shadow: 0 10px 35px rgba(14, 165, 233, 0.35);
}

.btn.accent::after {
    content: '';
    position: absolute;
    inset: 0;
    background: linear-gradient(90deg, rgba(255, 255, 255, 0.25), rgba(255, 255, 255, 0.05));
    transform: translateX(-100%);
    transition: transform 0.4s ease;
    pointer-events: none;
}

.btn.accent:hover {
    background-position: 100% 0;
    transform: translateY(-2px);
    box-shadow: 0 15px 40px rgba(14, 165, 233, 0.4);
}

.btn.accent:hover::after {
    transform: translateX(0);
}

.hero-stats {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
    gap: 14px;
    margin-top: 6px;
}

.stat-card {
    background: rgba(255, 255, 255, 0.14);
    border: 1px solid rgba(255, 255, 255, 0.2);
    border-radius: 16px;
    padding: 14px 16px;
    backdrop-filter: blur(6px);
    color: #0f172a;
}

.stat-card .label {
    font-size: 0.95rem;
    opacity: 0.8;
}

.stat-card .stat {
    font-family: var(--font-heading);
    font-size: 1.6rem;
    margin-top: 6px;
}

body.dark-mode .stat-card {
    background: rgba(255, 255, 255, 0.08);
    border-color: rgba(255, 255, 255, 0.18);
    color: #e5edff;
}

body.dark-mode .hero .eyebrow {
    background: rgba(255, 255, 255, 0.12);
    color: #e5edff;
    box-shadow: none;
}

body.dark-mode .hero-title,
body.dark-mode .hero-lead {
    color: #f8fbff;
    text-shadow: 0 12px 30px rgba(0, 0, 0, 0.45);
}

.hero-panel {
    background: var(--surface);
    color: var(--text);
    border-radius: var(--radius);
    padding: 26px;
    box-shadow: var(--shadow);
    border: 1px solid rgba(15, 23, 42, 0.05);
    position: relative;
    overflow: hidden;
    text-align: left;
}

.hero-panel::before {
    content: '';
    position: absolute;
    inset: 0;
    background: linear-gradient(145deg, rgba(14, 165, 233, 0.08), rgba(245, 158, 11, 0.08));
    pointer-events: none;
}

.hero-panel > * {
    position: relative;
    z-index: 1;
}

#particles-js {
    position: absolute;
    inset: 0;
    width: 100%;
    height: 100%;
    z-index: 0;
    opacity: 0.35;
}

.panel-kicker {
    color: var(--accent-2);
    font-weight: 700;
    letter-spacing: 0.06em;
    text-transform: uppercase;
    font-size: 0.8rem;
}

.hero-panel h3 {
    font-family: var(--font-heading);
    font-size: 1.6rem;
    margin: 6px 0;
}

.panel-meta {
    color: var(--muted);
    margin-bottom: 12px;
    font-weight: 600;
}

.panel-list {
    list-style: none;
    display: grid;
    gap: 10px;
    color: var(--text);
    text-align: left;
}

.panel-list li {
    padding-left: 22px;
    position: relative;
}

.panel-list li::before {
    content: '';
    position: absolute;
    left: 0;
    top: 10px;
    width: 10px;
    height: 10px;
    border-radius: 50%;
    background: var(--accent);
}

.focus-badges {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin: 16px 0;
}

.focus-badges span {
    background: rgba(15, 23, 42, 0.06);
    color: var(--text);
    padding: 8px 12px;
    border-radius: 12px;
    font-weight: 600;
}

.panel-footer {
    padding: 10px 12px;
    background: rgba(15, 23, 42, 0.05);
    border-radius: 12px;
    font-weight: 700;
}

/* Sections */
.section {
    padding: 90px 0;
    position: relative;
    opacity: 0;
    transform: translateY(24px);
    transition: opacity 0.6s ease, transform 0.6s ease;
}

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

.section:nth-of-type(even) {
    background: rgba(255, 255, 255, 0.62);
}

body.dark-mode .section:nth-of-type(even) {
    background: rgba(12, 22, 44, 0.6);
}

.section-header {
    text-align: center;
    margin-bottom: 38px;
}

.section-header h2 {
    font-family: var(--font-heading);
    font-size: 2.4rem;
    margin: 8px 0 10px;
}

.section-description {
    max-width: 760px;
    margin: 0 auto;
    color: var(--muted);
}

.lead-paragraph {
    font-size: 1.05rem;
    color: var(--text);
    margin-bottom: 18px;
}

.about-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
    gap: 18px;
    margin-top: 18px;
}

.about-card {
    background: var(--surface);
    border-radius: var(--radius);
    padding: 18px;
    box-shadow: var(--shadow);
    border: 1px solid rgba(15, 23, 42, 0.06);
}

.about-card h3 {
    font-family: var(--font-heading);
    margin-bottom: 8px;
}

/* Timeline */
.timeline {
    position: relative;
    margin-top: 24px;
    padding-left: 20px;
}

.timeline::before {
    content: '';
    position: absolute;
    left: 12px;
    top: 0;
    bottom: 0;
    width: 2px;
    background: linear-gradient(180deg, var(--accent), var(--accent-2));
    opacity: 0.7;
}

.timeline-card {
    position: relative;
    margin-bottom: 28px;
    background: var(--surface);
    border-radius: var(--radius);
    padding: 20px 22px 18px;
    box-shadow: var(--shadow);
    border: 1px solid rgba(15, 23, 42, 0.06);
}

.timeline-dot {
    position: absolute;
    left: -20px;
    top: 24px;
    width: 14px;
    height: 14px;
    border-radius: 50%;
    background: #fff;
    border: 4px solid var(--accent);
    box-shadow: 0 0 0 6px rgba(14, 165, 233, 0.1);
}

.timeline-meta {
    display: flex;
    justify-content: space-between;
    align-items: baseline;
    gap: 12px;
    flex-wrap: wrap;
}

.timeline-meta h3 {
    font-family: var(--font-heading);
    font-size: 1.3rem;
}

.company {
    color: var(--accent);
    font-weight: 700;
    display: inline-flex;
    align-items: center;
    gap: 8px;
}

.company-logo {
    width: 34px;
    height: 34px;
    object-fit: contain;
    border-radius: 6px;
    box-shadow: var(--shadow);
    background: #fff;
    padding: 4px;
}

.location {
    color: var(--muted);
    margin: 4px 0 10px;
    font-weight: 600;
}

/* Projects */
.projects-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 24px;
}

.project-card {
    background: var(--surface);
    border-radius: var(--radius);
    padding: 22px;
    border: 1px solid rgba(15, 23, 42, 0.06);
    box-shadow: var(--shadow);
    position: relative;
    overflow: hidden;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.project-card::after {
    content: '';
    position: absolute;
    inset: 0;
    background: linear-gradient(140deg, rgba(14, 165, 233, 0.12), rgba(245, 158, 11, 0.08));
    opacity: 0;
    transition: opacity 0.3s ease;
}

.project-card:hover {
    transform: translateY(-6px);
    box-shadow: 0 20px 50px rgba(15, 23, 42, 0.18);
}

.project-card:hover::after {
    opacity: 1;
}

.project-card > * { position: relative; z-index: 1; }

.project-top {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 10px;
}

.tech {
    margin-top: 14px;
    font-weight: 700;
    color: var(--accent);
}

.chip {
    display: inline-flex;
    align-items: center;
    padding: 6px 12px;
    border-radius: 999px;
    background: rgba(15, 23, 42, 0.06);
    color: var(--text);
    font-weight: 700;
    font-size: 0.85rem;
}

.chip.subtle {
    background: var(--pill);
    color: var(--text);
}

/* Skills */
.skills-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: 18px;
}

.skill-category {
    background: var(--surface);
    border-radius: var(--radius);
    padding: 20px;
    box-shadow: var(--shadow);
    border: 1px solid rgba(15, 23, 42, 0.06);
}

.skill-category h3 {
    display: flex;
    align-items: center;
    gap: 10px;
    margin-bottom: 12px;
    font-family: var(--font-heading);
}

.skill-category .pill-row .pill {
    background: rgba(14, 165, 233, 0.12);
    color: var(--text);
}

/* Education */
.education-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 20px;
}

.education-card {
    background: var(--surface);
    border-radius: var(--radius);
    padding: 20px;
    box-shadow: var(--shadow);
    border: 1px solid rgba(15, 23, 42, 0.06);
}

.education-header {
    display: flex;
    gap: 14px;
    align-items: center;
}

.school-logo {
    width: 70px;
    height: 70px;
    object-fit: contain;
    border-radius: 12px;
    box-shadow: var(--shadow);
}

.school-link {
    text-decoration: none;
    color: var(--text);
    transition: color 0.25s ease;
}

.school-link:hover {
    color: var(--accent);
}

/* Publications & patents */
.list-stack {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 20px;
}

.list-card {
    background: var(--surface);
    border-radius: var(--radius);
    padding: 20px;
    border: 1px solid rgba(15, 23, 42, 0.06);
    box-shadow: var(--shadow);
}

.list-card-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 10px;
    margin-bottom: 12px;
}

.list-card ul {
    list-style: none;
}

.list-card li {
    margin-bottom: 16px;
    padding: 14px;
    border-radius: 12px;
    background: rgba(15, 23, 42, 0.03);
    border: 1px solid rgba(15, 23, 42, 0.05);
    color: var(--text);
}

.hidden { display: none; }

.show-more-btn {
    width: 100%;
    border: none;
    margin-top: 6px;
    padding: 12px 16px;
    border-radius: 12px;
    background: linear-gradient(120deg, var(--accent), var(--accent-2));
    color: #0f172a;
    font-weight: 700;
    cursor: pointer;
    transition: transform 0.2s ease, box-shadow 0.25s ease;
}

.show-more-btn:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow);
}

/* Buttons and utilities */
.back-to-top {
    position: fixed;
    bottom: 24px;
    right: 24px;
    background: linear-gradient(160deg, var(--accent), var(--accent-2));
    color: #0f172a;
    border: none;
    border-radius: 50%;
    width: 52px;
    height: 52px;
    font-size: 1.1rem;
    cursor: pointer;
    box-shadow: var(--shadow);
    transition: transform 0.2s ease, box-shadow 0.25s ease;
}

.back-to-top:hover {
    transform: translateY(-3px);
}

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

/* Footer */
footer {
    background: var(--panel);
    color: #e5edff;
    text-align: center;
    padding: 24px 0;
}

/* Responsive */
@media (max-width: 1100px) {
    .hero-grid {
        padding: 90px 0 70px;
    }
}

@media (max-width: 900px) {
    .nav-container {
        padding: 16px 18px;
    }

    .nav-menu {
        position: fixed;
        top: 72px;
        right: -100%;
        width: 100%;
        height: calc(100vh - 72px);
        background: var(--panel);
        flex-direction: column;
        justify-content: center;
        align-items: center;
        gap: 22px;
        transition: right 0.3s ease;
        z-index: 999;
        padding: 20px;
        text-align: center;
    }

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

    .nav-menu li { margin: 0; }

    .nav-link { color: #e5edff; font-size: 1.1rem; }

    .nav-close {
        display: block;
        position: static;
        font-size: 2rem;
        cursor: pointer;
        color: #e5edff;
        align-self: center;
    }

    .nav-toggle { display: block; }

    .hero {
        padding: 0 0 20px;
    }

    .hero-grid {
        grid-template-columns: 1fr;
        padding: 80px 0 60px;
        text-align: center;
    }

    .hero-content {
        justify-items: center;
    }

    .hero-actions {
        justify-content: center;
    }

    .hero-panel {
        max-width: 640px;
        margin: 0 auto;
    }
}

@media (max-width: 600px) {
    body {
        padding-top: 70px;
    }

    .nav-container {
        padding: 14px 16px;
    }

    .hero-actions { flex-direction: column; align-items: center; }

    .hero-stats { grid-template-columns: repeat(auto-fit, minmax(140px, 1fr)); }

    .timeline { padding-left: 10px; }
    .timeline::before { left: 6px; }
    .timeline-card { padding: 18px; }
    .timeline-dot { left: -26px; }

    .section { padding: 64px 0; }

    .projects-grid,
    .skills-grid,
    .education-grid,
    .list-stack {
        grid-template-columns: 1fr;
    }

    .pill-row { justify-content: center; }

    .hero-tags { justify-content: center; }
}