/* ═══════════════════════════════════════════════
   CHARBEL ABI HANA — Professional Personal Website
   Clean, refined, no animations — with subtle depth
   ═══════════════════════════════════════════════ */

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

:root {
    /* Surface palette — warm-toned whites */
    --bg: #fdfdfe;
    --bg-alt: #f3f5f9;
    --bg-card: #ffffff;
    --bg-section-gradient: linear-gradient(180deg, #f4f6fa 0%, #edf0f6 100%);

    /* Borders — subtle but visible */
    --border: #d4d9e2;
    --border-light: #e6eaf1;
    --border-card: #dce0e8;

    /* Shadows — layered for real depth */
    --shadow-sm: 0 1px 3px rgba(30, 58, 95, 0.06), 0 1px 2px rgba(30, 58, 95, 0.04);
    --shadow-md: 0 4px 12px rgba(30, 58, 95, 0.07), 0 2px 4px rgba(30, 58, 95, 0.04);
    --shadow-lg: 0 8px 24px rgba(30, 58, 95, 0.09), 0 4px 8px rgba(30, 58, 95, 0.05);

    /* Text — high contrast for readability */
    --text: #0f1729;
    --text-secondary: #374263;
    --text-muted: #6b7a99;

    /* Accents */
    --accent: #1e3a5f;
    --accent-light: #2b547e;
    --accent-hover: #15294a;
    --accent-bg: rgba(30, 58, 95, 0.04);
    --link: #1d5296;

    /* Semantic colors */
    --green: #0e7a56;
    --gold: #9a6e1f;
    --orange: #b85c1f;
    --blue: #1d5296;

    /* Typography */
    --font-serif: 'Source Serif 4', 'Georgia', serif;
    --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    --font-mono: 'JetBrains Mono', 'Fira Code', monospace;

    /* Layout */
    --container: 960px;
    --radius: 10px;
    --radius-sm: 6px;
}

html {
    scroll-behavior: smooth;
    font-size: 16px;
}

body {
    font-family: var(--font-sans);
    background: linear-gradient(180deg,
            #fdfdfe 0%,
            #f0f3f9 15%,
            #eaeff7 30%,
            #f0f3f9 50%,
            #eaeff7 70%,
            #f0f3f9 85%,
            #fdfdfe 100%);
    color: var(--text);
    line-height: 1.7;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

a {
    color: var(--link);
    text-decoration: none;
}

a:hover {
    color: var(--accent-hover);
    text-decoration: underline;
}

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

.container {
    max-width: var(--container);
    margin: 0 auto;
    padding: 0 24px;
}

.section {
    padding: 80px 0;
    position: relative;
}

.section+.section::before {
    content: '';
    display: block;
    width: 120px;
    height: 1px;
    background: var(--border);
    position: absolute;
    top: 0;
    left: 50%;
    transform: translateX(-50%);
}

.section-alt {
    background: transparent;
}

.section-heading {
    font-family: var(--font-serif);
    font-size: 1.6rem;
    font-weight: 700;
    color: var(--text);
    margin-bottom: 32px;
    letter-spacing: -0.02em;
}

/* ─── Navigation ─── */
#navbar {
    position: sticky;
    top: 0;
    left: 0;
    right: 0;
    height: 52px;
    background: rgba(253, 253, 254, 0.88);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border-bottom: 1px solid rgba(30, 58, 95, 0.06);
    z-index: 100;
    box-shadow: 0 1px 8px rgba(30, 58, 95, 0.04);
}

.nav-container {
    max-width: var(--container);
    margin: 0 auto;
    padding: 0 24px;
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.nav-logo {
    font-family: var(--font-mono);
    font-size: 0.8rem;
    font-weight: 600;
    color: var(--text);
    text-decoration: none;
    letter-spacing: 0.02em;
}

.nav-logo:hover {
    text-decoration: none;
    color: var(--accent);
}

.nav-links {
    display: flex;
    gap: 4px;
}

.nav-links a {
    font-size: 0.8rem;
    font-weight: 500;
    color: var(--text-secondary);
    text-decoration: none !important;
    padding: 6px 12px;
    border-radius: 6px;
    transition: color 0.2s ease, background 0.2s ease;
}

.nav-links a:hover {
    color: var(--accent);
    background: rgba(30, 58, 95, 0.05);
    text-decoration: none;
}

.nav-links a.active {
    color: var(--accent);
    background: rgba(30, 58, 95, 0.07);
    font-weight: 600;
}

.nav-toggle {
    display: none;
    background: none;
    border: none;
    cursor: pointer;
    color: var(--text);
}

/* ─── Hero ─── */
#hero {
    padding: 72px 0 64px;
    background: linear-gradient(175deg, var(--bg) 0%, #eef2f8 60%, #e5ebf5 100%);
    border-bottom: 1px solid var(--border-light);
}

.hero-layout {
    display: grid;
    grid-template-columns: 200px 1fr;
    gap: 48px;
    align-items: start;
}

.hero-photo {
    display: flex;
    justify-content: center;
}

.profile-photo {
    width: 230px;
    height: 344px;
    border-radius: var(--radius);
    object-fit: cover;
    object-position: center top;
    box-shadow: var(--shadow-md);
    border: 1px solid var(--border);
}

.hero-text h1 {
    font-family: var(--font-serif);
    font-size: 2.4rem;
    font-weight: 700;
    color: var(--text);
    margin-bottom: 4px;
    line-height: 1.2;
}

.hero-title {
    font-size: 1.15rem;
    font-weight: 600;
    color: var(--accent);
    margin-bottom: 8px;
}

.hero-tagline {
    font-size: 0.92rem;
    color: var(--text-secondary);
    margin-bottom: 16px;
    font-family: var(--font-mono);
    letter-spacing: -0.01em;
}

.hero-summary {
    font-size: 0.95rem;
    color: var(--text-secondary);
    margin-bottom: 20px;
    max-width: 640px;
    line-height: 1.7;
}

.hero-meta {
    display: flex;
    gap: 24px;
    margin-bottom: 24px;
}

.meta-item {
    display: flex;
    align-items: center;
    gap: 6px;
    font-size: 0.85rem;
    color: var(--text-secondary);
}

.hero-links {
    display: flex;
    gap: 12px;
    flex-wrap: wrap;
}

/* Hero Logo Bar */
.hero-logos {
    margin-top: 28px;
    padding-top: 24px;
    border-top: 1px solid var(--border-light);
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 16px;
    grid-column: 1 / -1;
}

.hero-logos-row {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 32px;
    flex-wrap: wrap;
    width: 100%;
}

.hero-logo-item {
    display: flex;
    align-items: center;
    text-decoration: none;
    transition: transform 0.2s ease, opacity 0.2s ease;
}

.hero-logo-item:hover {
    transform: translateY(-2px);
    opacity: 0.75;
}

.hero-logo-item img {
    height: 36px;
    width: auto;
    object-fit: contain;
    filter: grayscale(30%);
    opacity: 0.8;
    transition: filter 0.2s ease, opacity 0.2s ease;
}

.hero-logo-item:hover img {
    filter: grayscale(0%);
    opacity: 1;
}

/* Per-logo size tuning for consistent visual text size */
.logo-nvidia {
    height: 20px !important;
}

.logo-idealworks {
    height: 22px !important;
}

.logo-bmw {
    height: 42px !important;
}

.logo-inmind {
    height: 28px !important;
    mix-blend-mode: multiply;
}

.logo-ens {
    height: 42px !important;
}

.logo-aamas {
    height: 38px !important;
}

.logo-ieee {
    height: 36px !important;
}

.hero-logo-divider {
    width: 1px;
    height: 36px;
    background: var(--border);
    margin: 0 4px;
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 9px 18px;
    border-radius: var(--radius);
    font-size: 0.85rem;
    font-weight: 500;
    text-decoration: none;
    border: 1px solid var(--border);
    color: var(--text-secondary);
    background: var(--bg-card);
    box-shadow: var(--shadow-sm);
    transition: all 0.2s ease;
}

.btn:hover {
    text-decoration: none;
    border-color: var(--accent);
    color: var(--accent);
    box-shadow: var(--shadow-md);
    transform: translateY(-1px);
}

.btn-primary {
    background: linear-gradient(135deg, var(--accent), var(--accent-light));
    color: #fff;
    border-color: var(--accent);
    box-shadow: 0 2px 8px rgba(30, 58, 95, 0.25);
}

.btn-primary:hover {
    background: linear-gradient(135deg, var(--accent-hover), var(--accent));
    color: #fff;
    border-color: var(--accent-hover);
    box-shadow: 0 4px 14px rgba(30, 58, 95, 0.3);
}

.btn-outline {
    background: transparent;
}

/* ─── About ─── */
.about-grid {
    display: block;
}

.about-text p {
    margin-bottom: 14px;
    font-size: 0.95rem;
    color: var(--text-secondary);
    line-height: 1.8;
}

.about-highlights {
    display: flex;
    flex-direction: column;
    gap: 14px;
}

.highlight-item {
    display: flex;
    gap: 16px;
    align-items: flex-start;
    padding: 16px;
    border: 1px solid var(--border-light);
    border-radius: var(--radius);
    background: var(--bg-card);
    box-shadow: var(--shadow-sm);
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

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

.highlight-icon {
    flex-shrink: 0;
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: var(--radius);
    background: linear-gradient(135deg, #eef2f8, #dfe6f2);
    border: 1px solid var(--border-light);
    color: var(--accent);
}

.highlight-item strong {
    display: block;
    font-size: 0.9rem;
    color: var(--text);
    margin-bottom: 2px;
}

.highlight-item span {
    font-size: 0.82rem;
    color: var(--text-secondary);
}

/* ─── Experience Timeline ─── */
.timeline {
    position: relative;
    padding-left: 180px;
}

.timeline::before {
    content: '';
    position: absolute;
    left: 167px;
    top: 8px;
    bottom: 8px;
    width: 2px;
    background: var(--border);
}

.timeline-item {
    position: relative;
    padding-bottom: 36px;
}

.timeline-item:last-child {
    padding-bottom: 0;
}

.timeline-date {
    position: absolute;
    left: -180px;
    top: 6px;
    width: 150px;
    text-align: right;
    font-family: var(--font-mono);
    font-size: 0.8rem;
    color: var(--text-secondary);
    white-space: nowrap;
    line-height: 16px;
}

.timeline-dot {
    position: absolute;
    left: -20px;
    top: 6px;
    width: 16px;
    height: 16px;
    border-radius: 50%;
    background: var(--accent);
    border: 3px solid var(--bg);
    box-shadow: 0 0 0 2px var(--accent);
    z-index: 1;
}

.timeline-item:first-child .timeline-dot {
    background: var(--accent);
    box-shadow: 0 0 0 2px var(--accent), 0 0 8px rgba(30, 58, 95, 0.3);
}

.timeline-content {
    margin-left: 12px;
    padding: 14px 18px;
    border: 1px solid var(--border-card);
    border-radius: var(--radius);
    background: var(--bg-card);
    box-shadow: var(--shadow-sm);
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

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

.timeline-header {
    display: flex;
    align-items: center;
    gap: 14px;
    margin-bottom: 10px;
}

.timeline-logo {
    width: 36px;
    height: 36px;
    object-fit: contain;
    border-radius: 6px;
    flex-shrink: 0;
}

.timeline-info {
    flex: 1;
    min-width: 0;
}

.timeline-role {
    font-family: var(--font-serif);
    font-size: 1.1rem;
    font-weight: 700;
    color: var(--text);
    margin-bottom: 2px;
    line-height: 1.3;
}

.timeline-company {
    font-size: 0.9rem;
    color: var(--accent);
    font-weight: 500;
}

.timeline-note {
    color: var(--text-muted);
    font-weight: 400;
}

.timeline-meta {
    display: flex;
    align-items: center;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 4px 16px;
}

.timeline-location {
    display: flex;
    align-items: center;
    gap: 5px;
    font-size: 0.82rem;
    color: var(--text-muted);
}

.timeline-location svg {
    flex-shrink: 0;
    color: var(--text-muted);
}

.timeline-dates {
    font-family: var(--font-mono);
    font-size: 0.8rem;
    color: var(--text-secondary);
    white-space: nowrap;
}

.timeline-gpa {
    font-family: var(--font-mono);
    font-size: 0.78rem;
    color: var(--text-muted);
    width: 100%;
}

#education .timeline-logo {
    width: 80px;
    height: 40px;
}

#education .logo-paris-saclay {
    width: 80px;
    height: 40px;
}

#education .logo-usek {
    width: 60px;
    height: 60px;
}

/* ─── Research ─── */
.research-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 20px;
}

.research-card {
    border: 1px solid var(--border-card);
    border-radius: var(--radius);
    padding: 24px;
    background: var(--bg-card);
    box-shadow: var(--shadow-sm);
    transition: transform 0.2s ease, box-shadow 0.2s ease, border-color 0.2s ease;
}

.research-card:hover {
    transform: translateY(-3px);
    border-color: var(--accent-light);
    box-shadow: var(--shadow-lg);
}

.card-top {
    margin-bottom: 12px;
}

.card-badge {
    font-family: var(--font-mono);
    font-size: 0.72rem;
    font-weight: 600;
    padding: 3px 10px;
    border-radius: 100px;
    border: 1px solid var(--border);
    color: var(--text-muted);
}

.badge-green {
    color: var(--green);
    border-color: var(--green);
    background: rgba(14, 122, 86, 0.06);
}

.badge-gold {
    color: var(--gold);
    border-color: var(--gold);
    background: rgba(154, 110, 31, 0.06);
}

.badge-blue {
    color: var(--blue);
    border-color: var(--blue);
    background: rgba(29, 82, 150, 0.06);
}

.badge-orange {
    color: var(--orange);
    border-color: var(--orange);
    background: rgba(184, 92, 31, 0.06);
}

.research-card h3 {
    font-size: 1.05rem;
    font-weight: 600;
    margin-bottom: 10px;
    line-height: 1.4;
    color: var(--text);
}

.research-card p {
    font-size: 0.88rem;
    color: var(--text-secondary);
    margin-bottom: 14px;
    line-height: 1.6;
}

.card-meta {
    display: flex;
    gap: 6px;
    flex-wrap: wrap;
    margin-bottom: 10px;
}

.card-meta span {
    font-size: 0.72rem;
    padding: 2px 8px;
    border-radius: var(--radius-sm);
    background: var(--bg-alt);
    color: var(--text-secondary);
    border: 1px solid var(--border-light);
}

.card-link {
    font-family: var(--font-mono);
    font-size: 0.8rem;
    color: var(--link);
    font-weight: 500;
}

/* ─── Publications ─── */
.pub-scholar-link {
    margin-bottom: 28px;
}

.pub-scholar-link a {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    font-size: 0.9rem;
    color: var(--link);
    font-weight: 500;
}

.pub-item {
    display: flex;
    gap: 20px;
    align-items: flex-start;
    padding: 24px;
    margin-bottom: 16px;
    border: 1px solid var(--border-card);
    border-radius: var(--radius);
    background: var(--bg-card);
    box-shadow: var(--shadow-sm);
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

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

.pub-venue {
    flex-shrink: 0;
    font-family: var(--font-mono);
    font-size: 0.72rem;
    font-weight: 700;
    padding: 6px 12px;
    border-radius: var(--radius-sm);
    min-width: 88px;
    text-align: center;
    color: var(--gold);
    background: rgba(154, 110, 31, 0.07);
    border: 1px solid rgba(154, 110, 31, 0.2);
}

.venue-blue {
    color: var(--blue);
    background: rgba(29, 82, 150, 0.07);
    border-color: rgba(29, 82, 150, 0.2);
}

.venue-muted {
    color: var(--text-secondary);
    background: var(--bg-alt);
    border-color: var(--border);
}

.pub-body h3 {
    font-size: 1rem;
    font-weight: 600;
    margin-bottom: 4px;
    line-height: 1.4;
}

.pub-authors {
    font-size: 0.88rem;
    color: var(--text-secondary);
    margin-bottom: 4px;
}

.pub-note {
    font-family: var(--font-mono);
    font-size: 0.75rem;
    color: var(--text-secondary);
    margin-bottom: 8px;
}

.pub-desc {
    font-size: 0.85rem;
    color: var(--text-secondary);
    margin-bottom: 8px;
    line-height: 1.6;
}

.pub-links {
    font-family: var(--font-mono);
    font-size: 0.8rem;
}

.pub-links span {
    color: var(--text-secondary);
    margin: 0 6px;
}

/* ─── Skills ─── */
.skills-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 20px;
}

.skill-group {
    padding: 24px;
    border: 1px solid var(--border-card);
    border-radius: var(--radius);
    background: var(--bg-card);
    box-shadow: var(--shadow-sm);
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

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

.skill-group h3 {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 0.95rem;
    font-weight: 600;
    color: var(--text);
    margin-bottom: 14px;
}

.skill-group h3 svg {
    color: var(--accent);
}

.tags {
    display: flex;
    gap: 6px;
    flex-wrap: wrap;
}

.tags span {
    font-size: 0.78rem;
    padding: 4px 12px;
    border-radius: 100px;
    border: 1px solid var(--border);
    color: var(--text-secondary);
    background: var(--bg-alt);
}

.tag-primary {
    font-weight: 500;
    color: var(--accent);
    border-color: var(--accent);
    background: rgba(30, 58, 95, 0.05);
}

.tag-code {
    font-family: var(--font-mono);
    font-weight: 500;
    color: var(--green);
    border-color: var(--green);
    background: rgba(14, 122, 86, 0.05);
}

/* ─── Education ─── */
.edu-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
    gap: 20px;
}

.edu-card {
    padding: 28px;
    border: 1px solid var(--border-card);
    border-radius: var(--radius);
    background: var(--bg-card);
    text-align: center;
    box-shadow: var(--shadow-sm);
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

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

.edu-degree-badge {
    display: inline-block;
    font-family: var(--font-mono);
    font-size: 0.85rem;
    font-weight: 700;
    color: var(--accent);
    padding: 4px 14px;
    border: 2px solid var(--accent);
    border-radius: 100px;
    margin-bottom: 14px;
    background: var(--accent-bg);
}

.edu-card h3 {
    font-size: 1rem;
    font-weight: 600;
    margin-bottom: 6px;
    line-height: 1.4;
}

.edu-school {
    font-size: 0.92rem;
    color: var(--accent);
    font-weight: 500;
    margin-bottom: 4px;
}

.edu-meta {
    font-size: 0.82rem;
    color: var(--text-secondary);
    margin-bottom: 8px;
}

.edu-courses {
    font-size: 0.78rem;
    color: var(--text-secondary);
    line-height: 1.6;
}

/* ─── Contact ─── */
#contact {
    background: linear-gradient(175deg, var(--bg) 0%, #eef2f8 100%);
}

.contact-container {
    text-align: center;
    max-width: 640px;
}

.contact-text {
    font-size: 1rem;
    color: var(--text-secondary);
    margin-bottom: 28px;
    line-height: 1.8;
}

.contact-links {
    display: flex;
    justify-content: center;
    gap: 12px;
    flex-wrap: wrap;
}

/* ─── Footer ─── */
footer {
    padding: 28px 0;
    text-align: center;
    border-top: 1px solid var(--border);
    font-size: 0.8rem;
    color: var(--text-muted);
    background: var(--bg-alt);
}

/* ─── Projects Page ─── */
.page-header {
    padding: 56px 0 40px;
    border-bottom: 1px solid var(--border-light);
    background: linear-gradient(175deg, var(--bg) 0%, #eef2f8 100%);
}

.page-title {
    font-family: var(--font-serif);
    font-size: 2.2rem;
    font-weight: 700;
    color: var(--text);
    margin-bottom: 8px;
}

.page-subtitle {
    font-size: 0.95rem;
    color: var(--text-secondary);
    line-height: 1.7;
}

.projects-intro {
    font-size: 0.95rem;
    color: var(--text-secondary);
    line-height: 1.7;
    margin-bottom: 32px;
}

.projects-group-title {
    font-family: var(--font-serif);
    font-size: 1.15rem;
    font-weight: 600;
    color: var(--text);
    margin-bottom: 16px;
    margin-top: 36px;
    padding-bottom: 8px;
    border-bottom: 1px solid var(--border-light);
}

.projects-group-title:first-of-type {
    margin-top: 0;
}

.active-page {
    color: var(--accent) !important;
    font-weight: 600 !important;
}

.project-card {
    padding: 28px;
    margin-bottom: 20px;
    border: 1px solid var(--border-card);

    border-radius: var(--radius);
    background: var(--bg-card);
    box-shadow: var(--shadow-md);
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

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

.project-card:last-child {
    margin-bottom: 0;
}

.project-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    gap: 20px;
    margin-bottom: 16px;
}

.project-header-left {
    flex: 1;
    min-width: 0;
}

.project-header-right {
    flex-shrink: 0;
    display: flex;
    flex-direction: column;
    align-items: flex-end;
    gap: 8px;
}

.project-name {
    font-family: var(--font-mono);
    font-size: 1.15rem;
    font-weight: 600;
    color: var(--text);
    margin-bottom: 4px;
}

.project-one-liner {
    font-size: 0.88rem;
    color: var(--text-secondary);
    line-height: 1.5;
}

.project-lang {
    font-family: var(--font-mono);
    font-size: 0.72rem;
    font-weight: 600;
    padding: 3px 10px;
    border-radius: 100px;
    border: 1px solid var(--border);
    color: var(--text-muted);
    white-space: nowrap;
}

.lang-python {
    color: var(--blue);
    border-color: var(--blue);
    background: rgba(29, 82, 150, 0.06);
}

.lang-jupyter {
    color: var(--orange);
    border-color: var(--orange);
    background: rgba(184, 92, 31, 0.06);
}

.lang-lua {
    color: var(--green);
    border-color: var(--green);
    background: rgba(14, 122, 86, 0.06);
}

.project-github-link {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    font-family: var(--font-mono);
    font-size: 0.78rem;
    color: var(--text-muted);
    text-decoration: none;
    white-space: nowrap;
}

.project-github-link:hover {
    color: var(--accent);
    text-decoration: none;
}

.project-body {
    margin-bottom: 16px;
}

.project-body>p {
    font-size: 0.9rem;
    color: var(--text-secondary);
    line-height: 1.7;
    margin-bottom: 16px;
}

.project-details {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: 16px;
    margin-bottom: 12px;
}

.detail-block {
    padding: 14px 16px;
    border: 1px solid var(--border-light);
    border-radius: var(--radius-sm);
    background: var(--bg-alt);
}

.detail-block h4 {
    font-size: 0.78rem;
    font-weight: 600;
    color: var(--text);
    text-transform: uppercase;
    letter-spacing: 0.06em;
    margin-bottom: 8px;
}

.detail-block ul {
    list-style: none;
    padding: 0;
}

.detail-block li {
    position: relative;
    padding-left: 14px;
    margin-bottom: 5px;
    font-size: 0.82rem;
    color: var(--text-secondary);
    line-height: 1.6;
}

.detail-block li::before {
    content: '\2013';
    position: absolute;
    left: 0;
    color: var(--accent);
    font-weight: 700;
}

.project-meta-row {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-top: 12px;
}

.pub-badge {
    font-family: var(--font-mono);
    font-size: 0.72rem;
    font-weight: 700;
    padding: 3px 12px;
    border-radius: var(--radius-sm);
    color: var(--gold);
    background: rgba(154, 110, 31, 0.07);
    border: 1px solid rgba(154, 110, 31, 0.2);
}

.project-ext-link {
    font-family: var(--font-mono);
    font-size: 0.78rem;
    color: var(--link);
    font-weight: 500;
}

.project-tags {
    display: flex;
    gap: 8px;
    flex-wrap: wrap;
    padding-top: 16px;
    border-top: 1px solid var(--border-light);
}

.project-tags span {
    font-family: var(--font-mono);
    font-size: 0.72rem;
    padding: 3px 10px;
    border-radius: 100px;
    border: 1px solid var(--border);
    color: var(--text-secondary);
    background: var(--bg-alt);
}

/* Tools Grid */
.tools-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 20px;
}

.tool-card {
    padding: 24px;
    border: 1px solid var(--border-card);
    border-radius: var(--radius);
    background: var(--bg-card);
    box-shadow: var(--shadow-sm);
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

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

.tool-card h3 {
    display: flex;
    align-items: center;
    gap: 8px;
    font-family: var(--font-mono);
    font-size: 0.95rem;
    font-weight: 600;
    color: var(--text);
    margin-bottom: 10px;
}

.tool-card h3 svg {
    color: var(--accent);
}

.tool-card p {
    font-size: 0.85rem;
    color: var(--text-secondary);
    line-height: 1.6;
    margin-bottom: 12px;
}

.tool-link {
    font-family: var(--font-mono);
    font-size: 0.78rem;
    color: var(--link);
    font-weight: 500;
}

/* ─── Responsive ─── */
@media (max-width: 768px) {
    .nav-links {
        display: none;
    }

    .nav-toggle {
        display: block;
    }

    .nav-links.open {
        display: flex;
        flex-direction: column;
        position: absolute;
        top: 52px;
        left: 0;
        right: 0;
        background: rgba(253, 253, 254, 0.95);
        backdrop-filter: blur(16px);
        -webkit-backdrop-filter: blur(16px);
        border-bottom: 1px solid var(--border);
        padding: 12px 24px;
        gap: 4px;
    }

    .hero-layout {
        grid-template-columns: 1fr;
        text-align: center;
    }

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

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

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

    .hero-summary {
        margin-left: auto;
        margin-right: auto;
    }

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

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

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

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

    .pub-item {
        flex-direction: column;
        gap: 8px;
    }

    .timeline {
        padding-left: 32px;
    }

    .timeline::before {
        left: 7px;
    }

    .timeline-date {
        position: static;
        width: auto;
        text-align: left;
        margin-bottom: 8px;
        white-space: normal;
    }

    .timeline-dot {
        left: -32px;
    }

    .project-header {
        flex-direction: column;
        gap: 8px;
    }

    .project-header-right {
        align-items: flex-start;
        flex-direction: row;
    }

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

@media (max-width: 480px) {
    .hero-text h1 {
        font-size: 1.8rem;
    }

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

    .btn {
        width: 100%;
        max-width: 260px;
        justify-content: center;
    }

    .contact-links {
        flex-direction: column;
        align-items: center;
    }
}