:root {
    --bg: #ffffff;
    --bg-nav: rgba(255, 255, 255, 0.95);
    --bg-card: #ffffff;
    --bg-featured: #f7f9ff;
    --bg-tag: #f2f2f2;
    --text: #1a1a1a;
    --text-muted: #555;
    --text-subtle: #666;
    --text-faint: #999;
    --text-body: #444;
    --border: #eee;
    --border-card: #e0e0e0;
    --accent: #0066ff;
    --accent-hover: #0044cc;
    --badge-fullstack-bg: #e8f0ff;
    --badge-fullstack-text: #0044cc;
    --badge-ml-bg: #e8fff4;
    --badge-ml-text: #007a40;
    --badge-degree-bg: #fff4e0;
    --badge-degree-text: #a05c00;
    --shadow: rgba(0, 0, 0, 0.1);
    --transition: background 0.3s, color 0.3s, border-color 0.3s;
}

html.dark {
    --bg: #111111;
    --bg-nav: rgba(17, 17, 17, 0.95);
    --bg-card: #1a1a1a;
    --bg-featured: #0d1a33;
    --bg-tag: #2a2a2a;
    --text: #e8e8e8;
    --text-muted: #aaa;
    --text-subtle: #888;
    --text-faint: #555;
    --text-body: #bbb;
    --border: #2a2a2a;
    --border-card: #333;
    --accent: #4d94ff;
    --accent-hover: #80b3ff;
    --badge-fullstack-bg: #0d1a33;
    --badge-fullstack-text: #80b3ff;
    --badge-ml-bg: #0d2b1a;
    --badge-ml-text: #4dbb87;
    --badge-degree-bg: #2b1d00;
    --badge-degree-text: #ffaa44;
    --shadow: rgba(0, 0, 0, 0.4);
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
    color: var(--text);
    background: var(--bg);
    line-height: 1.6;
    transition: var(--transition);
}

/* Scroll animations */
.fade-up {
    opacity: 0;
    transform: translateY(24px);
    transition: opacity 0.6s ease, transform 0.6s ease;
}

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

.fade-up:nth-child(2) { transition-delay: 0.1s; }
.fade-up:nth-child(3) { transition-delay: 0.2s; }
.fade-up:nth-child(4) { transition-delay: 0.3s; }

/* Nav */
header {
    position: sticky;
    top: 0;
    background: var(--bg-nav);
    border-bottom: 1px solid var(--border);
    z-index: 100;
    backdrop-filter: blur(8px);
    transition: var(--transition);
}

nav {
    max-width: 900px;
    margin: 0 auto;
    padding: 1rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-weight: 700;
    font-size: 1.2rem;
}

nav ul {
    list-style: none;
    display: flex;
    gap: 2rem;
    align-items: center;
}

nav a {
    text-decoration: none;
    color: var(--text-muted);
    font-size: 0.95rem;
    transition: color 0.2s;
}

nav a:hover {
    color: var(--text);
}

nav a.active {
    color: var(--accent);
    font-weight: 600;
}

/* Dark mode toggle */
#theme-toggle {
    background: none;
    border: 1px solid var(--border-card);
    border-radius: 6px;
    padding: 0.3rem 0.5rem;
    cursor: pointer;
    font-size: 1rem;
    line-height: 1;
    color: var(--text-muted);
    transition: var(--transition);
}

#theme-toggle:hover {
    border-color: var(--accent);
    color: var(--accent);
}

/* Sections */
main {
    max-width: 900px;
    margin: 0 auto;
    padding: 0 2rem;
}

section {
    padding: 5rem 0;
}

#hero {
    padding-top: 8rem;
    padding-bottom: 6rem;
}

h1 {
    font-size: 3rem;
    font-weight: 700;
    margin-bottom: 1rem;
}

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

.subtitle {
    font-size: 1.2rem;
    color: var(--text-subtle);
}

.hero-content {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 3rem;
}

.hero-text {
    flex: 1;
}

.avatar {
    width: 180px;
    height: 180px;
    border-radius: 10px;
    object-fit: cover;
    object-position: center top;
    flex-shrink: 0;
    border: 1px solid var(--border-card);
}

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

.btn {
    display: inline-block;
    padding: 0.6rem 1.4rem;
    border-radius: 6px;
    font-size: 0.95rem;
    font-weight: 500;
    text-decoration: none;
    transition: opacity 0.2s;
}

.btn:hover {
    opacity: 0.85;
}

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

.btn-secondary {
    border: 1px solid var(--border-card);
    color: var(--text-muted);
    background: transparent;
}

h2 {
    font-size: 1.8rem;
    margin-bottom: 1.5rem;
    border-bottom: 2px solid var(--accent);
    padding-bottom: 0.5rem;
    display: inline-block;
}

/* Timeline */
.timeline {
    margin-top: 1.5rem;
    display: flex;
    flex-direction: column;
    gap: 0.8rem;
}

.timeline-item {
    display: flex;
    gap: 1.5rem;
    align-items: center;
}

.year {
    font-size: 0.85rem;
    color: var(--accent);
    font-weight: 600;
    min-width: 110px;
    white-space: nowrap;
}

.event {
    color: var(--text-body);
    font-size: 0.95rem;
}

.logo-wrap {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 80px;
    flex-shrink: 0;
}

.school-logo {
    height: 28px;
    width: auto;
    object-fit: contain;
    mix-blend-mode: multiply;
}

html.dark .school-logo {
    mix-blend-mode: normal;
}

.school-logo--wide {
    height: 18px;
}


/* Projects */
.project-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(380px, 1fr));
    gap: 1.5rem;
    margin-top: 1.5rem;
}

.project-card {
    border: 1px solid var(--border-card);
    border-radius: 8px;
    padding: 1.5rem;
    background: var(--bg-card);
    transition: box-shadow 0.2s, var(--transition);
}

.project-card:hover {
    box-shadow: 0 4px 12px var(--shadow);
}

.card-label {
    font-size: 0.72rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.07em;
    color: var(--text-subtle);
    margin-bottom: 0.5rem;
}

.card-header {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    margin-bottom: 0.75rem;
    flex-wrap: wrap;
}

.card-header h3 {
    margin: 0;
}

.badge {
    font-size: 0.7rem;
    font-weight: 600;
    padding: 0.2rem 0.6rem;
    border-radius: 999px;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.badge-fullstack {
    background: var(--badge-fullstack-bg);
    color: var(--badge-fullstack-text);
}

.badge-ml {
    background: var(--badge-ml-bg);
    color: var(--badge-ml-text);
}

.badge-degree {
    background: var(--badge-degree-bg);
    color: var(--badge-degree-text);
}

.tags {
    display: flex;
    flex-wrap: wrap;
    gap: 0.4rem;
    margin-top: 1rem;
}

.tag {
    font-size: 0.78rem;
    background: var(--bg-tag);
    color: var(--text-muted);
    padding: 0.2rem 0.6rem;
    border-radius: 4px;
    transition: var(--transition);
}

/* Featured project */
.project-featured {
    border: 2px solid var(--accent);
    border-radius: 10px;
    padding: 2rem;
    margin-bottom: 2rem;
    background: var(--bg-featured);
    transition: var(--transition);
}

.featured-label {
    font-size: 0.75rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    color: var(--accent);
    margin-bottom: 0.6rem;
}

.project-featured h3 {
    font-size: 1.4rem;
    margin-bottom: 0.75rem;
}

.project-featured p {
    color: var(--text-body);
    line-height: 1.7;
}

/* Cities map */
.section-sub {
    color: var(--text-subtle);
    margin-bottom: 1.5rem;
    font-size: 0.95rem;
}

#map {
    height: 420px;
    border-radius: 10px;
    border: 1px solid var(--border-card);
    overflow: hidden;
}


/* City photo popup */
.city-photo-popup .leaflet-popup-content-wrapper {
    padding: 0;
    overflow: hidden;
    border-radius: 10px;
    box-shadow: 0 4px 20px rgba(0,0,0,0.18);
}
.city-photo-popup .leaflet-popup-content {
    margin: 0;
    padding: 0;
    width: 210px !important;
    line-height: 0;
}
.city-photo-popup img {
    width: 100%;
    height: 140px;
    object-fit: cover;
    display: block;
}
.city-photo-popup .popup-label {
    padding: 8px 12px 10px;
    font-size: 0.88rem;
    font-weight: 600;
    line-height: 1.3;
    color: var(--text);
    background: var(--bg-card);
}
.city-photo-popup .popup-note {
    display: block;
    font-size: 0.78rem;
    font-weight: 400;
    color: var(--text-faint);
    margin-top: 2px;
}
.city-photo-popup .leaflet-popup-tip-container {
    filter: drop-shadow(0 2px 4px rgba(0,0,0,0.12));
}

/* City list accordion */
#city-list {
    margin-top: 1.5rem;
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(72px, 1fr));
    gap: 0.4rem;
}

.cl-section {
    border: 1px solid transparent;
    border-radius: 8px;
    overflow: hidden;
    transition: var(--transition);
}

.cl-section.cl-open {
    grid-column: 1 / -1;
    border-color: var(--border-card);
}

.cl-header {
    width: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.6rem;
    padding: 0.7rem 0.5rem;
    background: var(--bg-tag);
    border: none;
    cursor: pointer;
    color: var(--text);
    transition: background 0.15s;
}

.cl-section.cl-open .cl-header {
    justify-content: flex-start;
    padding: 0.7rem 1rem;
    border-bottom: 1px solid var(--border);
}

.cl-header:hover {
    background: var(--bg-tag);
}

.cl-flag {
    width: 2.6rem;
    height: 1.95rem;
    flex-shrink: 0;
    border-radius: 3px;
}

.cl-meta {
    display: none;
    align-items: center;
    gap: 0.5rem;
}

.cl-section.cl-open .cl-meta {
    display: flex;
}

.cl-country {
    font-size: 0.9rem;
    font-weight: 500;
}

.cl-count {
    font-size: 0.78rem;
    color: var(--text-subtle);
    font-style: normal;
}

.cl-arrow {
    display: none;
    font-size: 1rem;
    color: var(--text-subtle);
    transition: transform 0.2s;
    margin-left: auto;
}

.cl-section.cl-open .cl-arrow {
    display: block;
    transform: rotate(90deg);
}

.cl-body {
    display: none;
    flex-wrap: wrap;
    gap: 0.4rem;
    padding: 0.6rem 1rem 0.8rem;
}

.cl-section.cl-open .cl-body {
    display: flex;
}

.cl-city {
    font-size: 0.82rem;
    color: var(--text-body);
    cursor: pointer;
    padding: 0.15rem 0.5rem;
    border-radius: 4px;
    background: var(--bg-tag);
    transition: background 0.15s, color 0.15s;
}

.cl-city:hover {
    background: var(--accent);
    color: #fff;
}

.cl-city em {
    font-style: normal;
    color: var(--text-subtle);
    font-size: 0.75rem;
}

.cl-city:hover em {
    color: rgba(255,255,255,0.8);
}

/* Skills */
.skills-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 2rem;
    margin-top: 1.5rem;
}

.skills-col h4 {
    font-size: 0.82rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.07em;
    color: var(--accent);
    margin-bottom: 0.8rem;
}

.skills-col ul {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 0.45rem;
}

.skills-col li {
    font-size: 0.95rem;
    color: var(--text-body);
}

/* Contact */
.contact-links {
    display: flex;
    flex-direction: column;
    gap: 0.8rem;
    margin-top: 0.5rem;
}

.contact-item {
    display: flex;
    align-items: center;
    gap: 0.6rem;
    color: var(--text-body);
    text-decoration: none;
    font-size: 1rem;
    transition: color 0.2s;
}

.contact-item:hover {
    color: var(--accent);
}

.card-link {
    display: inline-flex;
    align-items: center;
    margin-top: 1rem;
    color: var(--text-subtle);
    text-decoration: none;
    transition: color 0.2s;
}

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

/* Hamburger toggle */
.nav-toggle {
    display: none;
    background: none;
    border: 1px solid var(--border-card);
    border-radius: 6px;
    padding: 0.3rem 0.6rem;
    cursor: pointer;
    font-size: 1.1rem;
    color: var(--text-muted);
    transition: var(--transition);
}

.nav-toggle:hover {
    border-color: var(--accent);
    color: var(--accent);
}

/* Mobile */
@media (max-width: 768px) {
    nav {
        flex-wrap: wrap;
        padding: 0.8rem 1.2rem;
    }

    .nav-toggle {
        display: block;
    }

    .nav-menu {
        display: none;
        flex-direction: column;
        width: 100%;
        gap: 0;
        margin-top: 0.5rem;
        border-top: 1px solid var(--border);
        padding-top: 0.5rem;
    }

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

    .nav-menu li {
        padding: 0.4rem 0;
    }

    main {
        padding: 0 1.2rem;
    }

    section {
        padding: 3rem 0;
    }

    #hero {
        padding-top: 4rem;
        padding-bottom: 3rem;
    }

    .hero-content {
        flex-direction: column-reverse;
        align-items: flex-start;
        gap: 1.5rem;
    }

    .avatar {
        width: 110px;
        height: 110px;
    }

    h1 {
        font-size: 2.2rem;
    }

    .hero-actions {
        flex-direction: column;
    }

    .btn {
        text-align: center;
    }

    .timeline-item {
        flex-wrap: wrap;
        gap: 0.4rem;
    }

    .logo-wrap {
        width: auto;
    }

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

    #map {
        height: 300px;
    }

    #city-list {
        grid-template-columns: 1fr;
    }

    .skills-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    h2 {
        font-size: 1.5rem;
    }
}

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


    #map {
        height: 240px;
    }
}

/* Footer */
footer {
    text-align: center;
    padding: 2rem;
    color: var(--text-faint);
    font-size: 0.9rem;
    border-top: 1px solid var(--border);
    transition: var(--transition);
}