:root {
    --bg-primary: #0d1117;
    --bg-secondary: #161b22;
    --bg-card: #21262d;
    --bg-card-hover: #2d333b;
    --accent-blue: #0078D4;
    --accent-orange: #E25A1C;
    --accent-purple: #6929C4;
    --text-primary: #e6edf3;
    --text-secondary: #8b949e;
    --border: #30363d;
    --border-hover: #58a6ff;
    --radius: 12px;
    --transition: 0.25s ease;
}

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

html { scroll-behavior: smooth; }

body {
    font-family: 'Inter', sans-serif;
    background: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.7;
    overflow-x: hidden;
}

::-webkit-scrollbar { width: 6px; }
::-webkit-scrollbar-track { background: var(--bg-primary); }
::-webkit-scrollbar-thumb { background: var(--accent-blue); border-radius: 3px; }

.accent { color: var(--accent-blue); }
.container { max-width: 1100px; margin: 0 auto; padding: 0 2rem; }

/* ── NAVBAR ── */
#navbar {
    position: fixed;
    top: 0; left: 0; right: 0;
    z-index: 100;
    padding: 1rem 0;
    transition: background var(--transition), border-bottom var(--transition);
}
#navbar.scrolled {
    background: rgba(13, 17, 23, 0.95);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border);
}
.nav-container {
    max-width: 1100px;
    margin: 0 auto;
    padding: 0 2rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
}
.nav-logo {
    font-family: 'Fira Code', monospace;
    font-size: 1.4rem;
    font-weight: 700;
    color: var(--text-primary);
}
.nav-links {
    display: flex;
    gap: 2rem;
    list-style: none;
}
.nav-links a {
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 0.9rem;
    font-weight: 500;
    transition: color var(--transition);
}
.nav-links a:hover { color: var(--text-primary); }
.nav-hamburger { display: none; flex-direction: column; gap: 5px; cursor: pointer; }
.nav-hamburger span { width: 24px; height: 2px; background: var(--text-primary); transition: var(--transition); }

/* ── HERO ── */
#hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    position: relative;
    overflow: hidden;
    padding: 6rem 2rem 4rem;
}
.hero-content {
    max-width: 700px;
    margin: 0 auto;
    text-align: center;
    position: relative;
    z-index: 2;
}
.hero-greeting {
    font-family: 'Fira Code', monospace;
    color: var(--accent-blue);
    font-size: 1rem;
    margin-bottom: 0.5rem;
    opacity: 0;
    animation: fadeUp 0.6s ease 0.2s forwards;
}
.hero-name {
    font-size: clamp(2.5rem, 6vw, 4.5rem);
    font-weight: 700;
    line-height: 1.1;
    margin-bottom: 1rem;
    opacity: 0;
    animation: fadeUp 0.6s ease 0.4s forwards;
}
.hero-typing {
    font-family: 'Fira Code', monospace;
    font-size: clamp(1rem, 2.5vw, 1.3rem);
    color: var(--text-secondary);
    min-height: 2em;
    margin-bottom: 1.5rem;
    opacity: 0;
    animation: fadeUp 0.6s ease 0.6s forwards;
}
.cursor {
    display: inline-block;
    animation: blink 1s step-end infinite;
    color: var(--accent-blue);
}
.hero-desc {
    color: var(--text-secondary);
    font-size: 1.05rem;
    max-width: 520px;
    margin: 0 auto 2rem;
    opacity: 0;
    animation: fadeUp 0.6s ease 0.8s forwards;
}
.hero-cta {
    display: flex;
    gap: 1rem;
    justify-content: center;
    flex-wrap: wrap;
    opacity: 0;
    animation: fadeUp 0.6s ease 1s forwards;
}
.btn {
    padding: 0.75rem 1.75rem;
    border-radius: 8px;
    font-size: 0.95rem;
    font-weight: 600;
    text-decoration: none;
    transition: transform var(--transition), box-shadow var(--transition), background var(--transition);
    display: inline-block;
}
.btn-primary {
    background: var(--accent-blue);
    color: #fff;
}
.btn-primary:hover {
    background: #1a8ae0;
    transform: translateY(-2px);
    box-shadow: 0 8px 24px rgba(0, 120, 212, 0.35);
}
.btn-secondary {
    background: transparent;
    color: var(--text-primary);
    border: 1px solid var(--border);
}
.btn-secondary:hover {
    border-color: var(--accent-blue);
    color: var(--accent-blue);
    transform: translateY(-2px);
}
.hero-orb {
    position: absolute;
    border-radius: 50%;
    filter: blur(80px);
    opacity: 0.15;
    pointer-events: none;
}
.orb-1 {
    width: 500px; height: 500px;
    background: var(--accent-blue);
    top: -100px; right: -100px;
    animation: float 8s ease-in-out infinite;
}
.orb-2 {
    width: 350px; height: 350px;
    background: var(--accent-orange);
    bottom: -50px; left: -50px;
    animation: float 10s ease-in-out infinite reverse;
}

/* ── SECTIONS ── */
section { padding: 6rem 0; }
section:nth-child(even) { background: var(--bg-secondary); }
.section-title {
    font-size: clamp(1.8rem, 4vw, 2.5rem);
    font-weight: 700;
    margin-bottom: 3rem;
}

/* ── ABOUT ── */
.about-grid {
    display: grid;
    grid-template-columns: auto 1fr auto;
    gap: 3rem;
    align-items: start;
}
.about-photo { display: flex; justify-content: center; align-items: flex-start; }
.profile-photo {
    width: 200px;
    height: 200px;
    min-width: 200px;
    border-radius: 50%;
    object-fit: cover;
    object-position: center top;
    border: 3px solid var(--accent-blue);
    box-shadow: 0 0 0 6px rgba(0, 120, 212, 0.15);
    transition: transform var(--transition), box-shadow var(--transition);
    display: block;
}
.profile-photo:hover {
    transform: scale(1.04);
    box-shadow: 0 0 0 8px rgba(0, 120, 212, 0.25);
}
.about-text p {
    color: var(--text-secondary);
    margin-bottom: 1rem;
    font-size: 1.02rem;
}
.about-text strong { color: var(--text-primary); }
.about-stats {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 1rem;
}
.stat-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 1.5rem 1rem;
    text-align: center;
    transition: border-color var(--transition), transform var(--transition);
}
.stat-card:hover {
    border-color: var(--accent-blue);
    transform: translateY(-4px);
}
.stat-number {
    display: block;
    font-size: 2rem;
    font-weight: 700;
    color: var(--accent-blue);
    font-family: 'Fira Code', monospace;
}
.stat-label {
    display: block;
    font-size: 0.8rem;
    color: var(--text-secondary);
    margin-top: 0.25rem;
}

/* ── TIMELINE ── */
.timeline { position: relative; padding-left: 2rem; }
.timeline::before {
    content: '';
    position: absolute;
    left: 0; top: 0; bottom: 0;
    width: 2px;
    background: linear-gradient(to bottom, var(--accent-blue), var(--accent-orange));
}
.timeline-item { position: relative; margin-bottom: 2rem; }
.timeline-dot {
    position: absolute;
    left: -2.45rem;
    top: 0.4rem;
    width: 14px; height: 14px;
    border-radius: 50%;
    background: var(--accent-blue);
    border: 2px solid var(--bg-secondary);
    box-shadow: 0 0 0 3px var(--accent-blue);
}
.timeline-content {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 1.75rem;
    transition: border-color var(--transition);
}
.timeline-content:hover { border-color: var(--accent-blue); }
.timeline-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    flex-wrap: wrap;
    gap: 0.5rem;
    margin-bottom: 1rem;
}
.timeline-header h3 { font-size: 1.2rem; font-weight: 600; }
.timeline-company {
    display: block;
    color: var(--accent-blue);
    font-size: 0.9rem;
    font-weight: 500;
    margin-top: 0.15rem;
}
.timeline-date {
    font-family: 'Fira Code', monospace;
    font-size: 0.85rem;
    color: var(--text-secondary);
    white-space: nowrap;
}
.timeline-bullets {
    list-style: none;
    margin-bottom: 1.25rem;
}
.timeline-bullets li {
    color: var(--text-secondary);
    font-size: 0.95rem;
    padding: 0.3rem 0 0.3rem 1.25rem;
    position: relative;
}
.timeline-bullets li::before {
    content: '▹';
    position: absolute;
    left: 0;
    color: var(--accent-blue);
}
.timeline-bullets strong { color: var(--text-primary); }
.timeline-tags { display: flex; flex-wrap: wrap; gap: 0.5rem; }
.tag {
    background: rgba(0, 120, 212, 0.12);
    color: var(--accent-blue);
    border: 1px solid rgba(0, 120, 212, 0.3);
    border-radius: 6px;
    padding: 0.2rem 0.7rem;
    font-size: 0.8rem;
    font-weight: 500;
}

/* ── EDUCATION ── */
.edu-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 1.25rem;
}
.edu-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 1.5rem;
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
    transition: border-color var(--transition), transform var(--transition);
}
.edu-card:hover {
    border-color: var(--accent-blue);
    transform: translateY(-4px);
}
.edu-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    flex-wrap: wrap;
    gap: 0.5rem;
}
.edu-header h3 { font-size: 1rem; font-weight: 600; }
.edu-school {
    display: block;
    color: var(--accent-blue);
    font-size: 0.875rem;
    font-weight: 500;
    margin-top: 0.2rem;
}
.edu-note { font-size: 0.82rem; color: var(--text-secondary); }
.edu-badge {
    display: inline-block;
    font-size: 0.72rem;
    font-weight: 600;
    padding: 0.15rem 0.6rem;
    border-radius: 5px;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    align-self: flex-start;
}
.edu-badge.current {
    background: rgba(0, 120, 212, 0.15);
    color: #58a6ff;
    border: 1px solid rgba(0, 120, 212, 0.3);
}
.timeline-type {
    display: block;
    font-size: 0.78rem;
    color: var(--text-secondary);
    font-style: italic;
    margin-top: 0.1rem;
}

/* ── SKILLS ── */
.skills-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 1.5rem;
}
.skill-category {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 1.5rem;
    transition: border-color var(--transition), transform var(--transition);
}
.skill-category:hover {
    border-color: var(--accent-blue);
    transform: translateY(-4px);
}
.skill-category h3 {
    font-size: 1rem;
    font-weight: 600;
    margin-bottom: 1rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}
.skill-tags { display: flex; flex-wrap: wrap; gap: 0.5rem; }
.skill-tag {
    background: var(--bg-secondary);
    color: var(--text-secondary);
    border: 1px solid var(--border);
    border-radius: 6px;
    padding: 0.25rem 0.75rem;
    font-size: 0.82rem;
    font-weight: 500;
    transition: all var(--transition);
    cursor: default;
}
.skill-tag:hover {
    color: var(--accent-blue);
    border-color: var(--accent-blue);
    background: rgba(0, 120, 212, 0.08);
}

/* ── PROJECTS ── */
.filter-bar {
    display: flex;
    gap: 0.75rem;
    flex-wrap: wrap;
    margin-bottom: 2.5rem;
}
.filter-btn {
    background: var(--bg-card);
    color: var(--text-secondary);
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 0.45rem 1.1rem;
    font-size: 0.85rem;
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition);
    font-family: 'Inter', sans-serif;
}
.filter-btn:hover, .filter-btn.active {
    background: var(--accent-blue);
    color: #fff;
    border-color: var(--accent-blue);
}
.projects-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 1.5rem;
}
.project-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 1.5rem;
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
    transition: border-color var(--transition), transform var(--transition), box-shadow var(--transition);
}
.project-card:hover {
    border-color: var(--accent-blue);
    transform: translateY(-5px);
    box-shadow: 0 12px 32px rgba(0, 120, 212, 0.12);
}
.project-card.hidden { display: none; }
.project-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
}
.project-category-badge {
    font-size: 0.75rem;
    font-weight: 600;
    padding: 0.2rem 0.6rem;
    border-radius: 5px;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}
.project-category-badge.data { background: rgba(0, 120, 212, 0.15); color: #58a6ff; }
.project-category-badge.web  { background: rgba(226, 90, 28, 0.15);  color: #f0883e; }
.project-category-badge.ml   { background: rgba(105, 41, 196, 0.15); color: #bc8cff; }
.project-category-badge.research { background: rgba(46, 160, 67, 0.15); color: #3fb950; }
.project-link {
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 1.2rem;
    transition: color var(--transition);
}
.project-link:hover { color: var(--accent-blue); }
.project-card h3 { font-size: 1.05rem; font-weight: 600; }
.project-card p { color: var(--text-secondary); font-size: 0.9rem; flex: 1; }
.project-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 0.4rem;
    margin-top: auto;
}
.project-tags span {
    background: var(--bg-secondary);
    color: var(--text-secondary);
    border-radius: 5px;
    padding: 0.15rem 0.6rem;
    font-size: 0.78rem;
    font-family: 'Fira Code', monospace;
}

/* ── CONTACT ── */
.contact-desc {
    color: var(--text-secondary);
    font-size: 1.05rem;
    margin-bottom: 2.5rem;
}
.contact-links {
    display: flex;
    gap: 1.5rem;
    flex-wrap: wrap;
}
.contact-card {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.5rem;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 2rem 2.5rem;
    text-decoration: none;
    color: var(--text-primary);
    transition: all var(--transition);
    min-width: 160px;
}
.contact-card:hover {
    border-color: var(--accent-blue);
    transform: translateY(-5px);
    box-shadow: 0 12px 32px rgba(0, 120, 212, 0.15);
}
.contact-icon {
    width: 48px; height: 48px;
    background: var(--accent-blue);
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-family: 'Fira Code', monospace;
    font-weight: 700;
    font-size: 1rem;
    color: #fff;
}
.contact-label { font-weight: 600; font-size: 0.95rem; }
.contact-sub { font-size: 0.78rem; color: var(--text-secondary); text-align: center; }

/* ── FOOTER ── */
footer {
    background: var(--bg-secondary);
    border-top: 1px solid var(--border);
    padding: 2rem;
}
.footer-content {
    max-width: 1100px;
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
    color: var(--text-secondary);
    font-size: 0.85rem;
}
.footer-content a {
    color: var(--text-secondary);
    text-decoration: none;
    transition: color var(--transition);
}
.footer-content a:hover { color: var(--accent-blue); }

/* ── ANIMATIONS ── */
@keyframes fadeUp {
    from { opacity: 0; transform: translateY(20px); }
    to   { opacity: 1; transform: translateY(0); }
}
@keyframes blink {
    0%, 100% { opacity: 1; }
    50%       { opacity: 0; }
}
@keyframes float {
    0%, 100% { transform: translateY(0); }
    50%       { transform: translateY(-30px); }
}
.fade-in {
    opacity: 0;
    transform: translateY(24px);
    transition: opacity 0.6s ease, transform 0.6s ease;
}
.fade-in.visible {
    opacity: 1;
    transform: translateY(0);
}

/* ── RESPONSIVE ── */
@media (max-width: 768px) {
    .nav-links { display: none; }
    .nav-hamburger { display: flex; }
    .nav-links.open {
        display: flex;
        flex-direction: column;
        position: fixed;
        top: 0; left: 0; right: 0; bottom: 0;
        background: var(--bg-primary);
        align-items: center;
        justify-content: center;
        gap: 2rem;
        font-size: 1.2rem;
        z-index: 99;
    }
    .about-grid { grid-template-columns: 1fr; gap: 2rem; justify-items: center; }
    .about-photo { width: auto; }
    .profile-photo { width: 150px; height: 150px; min-width: 150px; }
    .about-text { text-align: center; width: 100%; }
    .about-stats { grid-template-columns: repeat(3, 1fr); width: 100%; }
    .timeline { padding-left: 1.5rem; }
    .contact-links { flex-direction: column; }
    .contact-card { flex-direction: row; min-width: unset; padding: 1.25rem 1.5rem; }
}
@media (max-width: 480px) {
    .about-stats { grid-template-columns: 1fr; }
    .hero-cta { flex-direction: column; align-items: center; }
    .filter-bar { gap: 0.5rem; }
}