:root {
    --primary-bg: #121212;
    --secondary-bg: #1e1e1e;
    --accent-color: #c0c0c0;
    --text-color: #f5f5f5;
    --card-bg: #252525;
    --hover-color: #e0e0e0;
    --track-accent: #c0c0c0;
}
* { margin: 0; padding: 0; box-sizing: border-box; }
body { font-family: 'Poppins', sans-serif; background-color: var(--primary-bg); color: var(--text-color); line-height: 1.6; overflow-x: hidden; }
.section { padding: 80px 0; }
.container { max-width: 1200px; margin: 0 auto; padding: 0 30px; }
.section-title { text-align: center; margin-bottom: 50px; position: relative; }
.section-title h2 { font-size: 2.5rem; font-weight: 600; position: relative; display: inline-block; }
.section-title h2::after { content: ''; position: absolute; width: 50%; height: 3px; background-color: var(--track-accent); bottom: -10px; left: 25%; }
.section-sub { text-align: center; max-width: 700px; margin: -30px auto 50px; opacity: .8; }

/* Header */
header { background-color: rgba(30,30,30,.95); position: fixed; width: 100%; z-index: 1000; box-shadow: 0 2px 10px rgba(0,0,0,.3); transition: all .3s ease; }
header.scrolled { padding: 10px 0; background-color: rgba(18,18,18,.95); }
nav { display: flex; justify-content: space-between; align-items: center; padding: 20px 0; }
.logo img { height: 40px; }
.logo a { color: var(--text-color); text-decoration: none; font-weight: 600; font-size: 1.1rem; }
.nav-links { display: flex; list-style: none; align-items: center; }
.nav-links li { margin-left: 30px; }
.nav-links a { color: var(--text-color); text-decoration: none; font-weight: 500; font-size: 1rem; transition: all .3s ease; position: relative; }
.nav-links a::after { content: ''; position: absolute; width: 0; height: 2px; background-color: var(--track-accent); bottom: -5px; left: 0; transition: width .3s ease; }
.nav-links a:hover::after, .nav-links a.current::after { width: 100%; }
.nav-links a.current { color: var(--track-accent); }
.menu-toggle { display: none; cursor: pointer; font-size: 1.5rem; }

/* Track switcher */
.track-bar { display: flex; gap: 10px; align-items: center; }
.track-pill { padding: 6px 14px; border-radius: 50px; border: 1px solid rgba(255,255,255,.18); font-size: .8rem; text-decoration: none; color: var(--text-color); transition: all .3s ease; white-space: nowrap; }
.track-pill:hover { border-color: var(--track-accent); background: color-mix(in srgb, var(--track-accent) 14%, transparent); color: var(--text-color); }
.track-pill.current { background: color-mix(in srgb, var(--track-accent) 18%, transparent); border-color: var(--track-accent); color: var(--track-accent); font-weight: 600; }
.track-pill.current:hover { background: color-mix(in srgb, var(--track-accent) 26%, transparent); color: var(--track-accent); }
.track-pill::after { content: none; }

/* Hero */
.hero { min-height: 100vh; display: flex; align-items: center; background-color: var(--secondary-bg); position: relative; overflow: hidden; padding: 140px 0 80px; }
.hero::before { content: ''; position: absolute; top: 0; left: 0; width: 100%; height: 100%; background: linear-gradient(45deg, rgba(30,30,30,.85) 0%, rgba(18,18,18,.85) 100%); z-index: 1; }
.hero-content { position: relative; z-index: 2; max-width: 800px; }
.hero-mark { width: 124px; height: 124px; border-radius: 30px; margin-bottom: 22px; box-shadow: 0 12px 32px rgba(0,0,0,.5); border: 1px solid rgba(255,255,255,.1); }
.hero-kicker { display: inline-block; padding: 6px 16px; border: 1px solid var(--track-accent); border-radius: 50px; font-size: .85rem; margin-bottom: 20px; color: var(--track-accent); letter-spacing: .05em; text-transform: uppercase; }
.hero h1 { font-size: 3.2rem; font-weight: 700; margin-bottom: 20px; line-height: 1.2; }
.hero h1 span { color: var(--track-accent); }
.hero p { font-size: 1.15rem; margin-bottom: 15px; max-width: 640px; }
.hero-meta { display: flex; flex-wrap: wrap; gap: 8px; margin: 20px 0 30px; }
.hero-meta span { font-size: .8rem; padding: 5px 12px; background: var(--card-bg); border-radius: 4px; color: var(--track-accent); }
.hero-buttons { display: flex; gap: 20px; flex-wrap: wrap; }
.btn { display: inline-block; padding: 12px 30px; background-color: var(--track-accent); color: var(--primary-bg); text-decoration: none; border-radius: 5px; font-weight: 500; transition: all .3s ease; border: 2px solid var(--track-accent); }
.btn:hover { background-color: transparent; color: var(--track-accent); }
.btn-outline { background-color: transparent; color: var(--track-accent); }
.btn-outline:hover { background-color: var(--track-accent); color: var(--primary-bg); }

/* About */
#about { background-color: var(--primary-bg); }
.about-container { display: grid; grid-template-columns: 1fr 1fr; gap: 50px; align-items: center; }
.about-image { position: relative; border-radius: 10px; overflow: hidden; box-shadow: 0 10px 20px rgba(0,0,0,.3); }
.about-image img { width: 100%; display: block; transition: transform .5s ease; }
.about-image:hover img { transform: scale(1.05); }
.about-content h2 { font-size: 2rem; margin-bottom: 20px; color: var(--track-accent); }
.about-content p { margin-bottom: 15px; font-size: 1.05rem; }
.skills { margin-top: 30px; }
.skills h3 { font-size: 1.4rem; margin-bottom: 15px; color: var(--track-accent); }
.skills-list { display: flex; flex-wrap: wrap; gap: 10px; list-style: none; }
.skills-list li { padding: 8px 15px; background-color: var(--card-bg); border-radius: 50px; font-size: .9rem; transition: all .3s ease; border: 1px solid var(--track-accent); }
.skills-list li:hover { background-color: var(--track-accent); color: var(--primary-bg); transform: translateY(-3px); }

/* Experience */
#experience { background-color: var(--primary-bg); }
.exp-item { background: var(--card-bg); border-radius: 10px; padding: 25px 30px; margin-bottom: 20px; box-shadow: 0 5px 15px rgba(0,0,0,.2); border: 1px solid rgba(255,255,255,.06); transition: all .3s ease; }
.exp-item:hover { border-color: color-mix(in srgb, var(--track-accent) 45%, transparent); transform: translateY(-3px); box-shadow: 0 10px 25px rgba(0,0,0,.35); }
.exp-item h3 { font-size: 1.25rem; color: var(--track-accent); display: flex; align-items: center; gap: 10px; }
.exp-item h3::before { content: ''; width: 8px; height: 8px; border-radius: 50%; background: var(--track-accent); flex-shrink: 0; }
.exp-meta { font-size: .9rem; opacity: .75; margin-bottom: 10px; }
.exp-item ul { margin-left: 20px; }
.exp-item li { margin-bottom: 6px; font-size: .97rem; }

/* Portfolio */
#portfolio, #projects { background-color: var(--secondary-bg); }
.portfolio-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(320px, 1fr)); gap: 30px; }
.portfolio-item { background-color: var(--card-bg); border-radius: 10px; overflow: hidden; box-shadow: 0 5px 15px rgba(0,0,0,.2); transition: all .3s ease; height: 100%; display: flex; flex-direction: column; }
.portfolio-item:hover { transform: translateY(-10px); box-shadow: 0 15px 30px rgba(0,0,0,.4); }
.portfolio-item.featured { border: 1px solid var(--track-accent); }
.portfolio-image { height: 180px; overflow: hidden; }
.portfolio-image img { width: 100%; height: 100%; object-fit: cover; transition: transform .5s ease; }
.portfolio-item:hover .portfolio-image img { transform: scale(1.08); }
.cover-art { height: 100%; display: flex; align-items: center; justify-content: center; background: linear-gradient(135deg, color-mix(in srgb, var(--track-accent) 16%, var(--card-bg)), var(--card-bg) 70%); }
.cover-art .mono-initials { font-size: 3.6rem; font-weight: 700; color: color-mix(in srgb, var(--track-accent) 75%, transparent); letter-spacing: .05em; }
.cover-logo { height: 100%; display: flex; align-items: center; justify-content: center; background: radial-gradient(circle at center, rgba(255,255,255,.05), transparent 65%), var(--secondary-bg); }
.cover-logo img { width: auto; height: 62%; max-width: 70%; object-fit: contain; transition: transform .3s ease; }
.portfolio-item:hover .cover-logo img { transform: scale(1.06); }
.portfolio-content { padding: 20px; flex-grow: 1; display: flex; flex-direction: column; }
.portfolio-content h3 { font-size: 1.3rem; margin-bottom: 10px; color: var(--track-accent); }
.portfolio-content p { margin-bottom: 12px; font-size: .95rem; flex-grow: 1; }
.portfolio-content ul { margin: 0 0 12px 18px; font-size: .9rem; }
.portfolio-content ul li { margin-bottom: 4px; }
.tech-stack { display: flex; flex-wrap: wrap; gap: 5px; margin-bottom: 15px; }
.tech-tag { font-size: .75rem; padding: 3px 8px; background-color: rgba(192,192,192,.1); border-radius: 4px; color: var(--track-accent); }
.portfolio-links { display: flex; gap: 10px; }
.portfolio-links a { padding: 8px 15px; font-size: .9rem; text-decoration: none; border-radius: 5px; transition: all .3s ease; text-align: center; flex: 1; }
.demo-link { background-color: var(--track-accent); color: var(--primary-bg); }
.demo-link:hover { background-color: var(--hover-color); }
.repo-link { background-color: transparent; color: var(--track-accent); border: 1px solid var(--track-accent); }
.repo-link:hover { background-color: var(--track-accent); color: var(--primary-bg); }

/* Hub cards */
.hub-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); gap: 25px; }
.hub-card { background: var(--card-bg); border-radius: 12px; padding: 35px 30px; text-decoration: none; color: var(--text-color); border: 1px solid transparent; transition: all .3s ease; display: flex; flex-direction: column; }
.hub-card:hover { transform: translateY(-8px); border-color: var(--track-accent); box-shadow: 0 15px 30px rgba(0,0,0,.4); }
.hub-card .hub-icon { font-size: 2.2rem; margin-bottom: 15px; }
.hub-card h3 { font-size: 1.5rem; margin-bottom: 10px; }
.hub-card p { font-size: .95rem; opacity: .85; margin-bottom: 15px; flex-grow: 1; }
.hub-card .hub-tags { display: flex; flex-wrap: wrap; gap: 6px; margin-bottom: 20px; }
.hub-card .hub-tags span { font-size: .75rem; padding: 3px 10px; background: rgba(255,255,255,.07); border-radius: 4px; }
.hub-card .hub-cta { font-weight: 600; }

/* Contact */
#contact { background-color: var(--primary-bg); }
.contact-container { max-width: 700px; margin: 0 auto; text-align: center; }
.contact-message { margin-bottom: 40px; font-size: 1.15rem; }
.contact-icons { display: flex; justify-content: center; gap: 30px; margin-bottom: 40px; }
.contact-icons a { font-size: 2rem; color: var(--text-color); transition: all .3s ease; }
.contact-icons a:hover { color: var(--track-accent); transform: translateY(-5px); }
.resume-cta { margin-bottom: 35px; }

/* Footer */
footer { background-color: var(--secondary-bg); text-align: center; padding: 30px 0; position: relative; }
.footer-tracks { margin-bottom: 12px; }
.footer-tracks a { color: var(--text-color); opacity: .7; text-decoration: none; margin: 0 10px; font-size: .9rem; }
.footer-tracks a:hover { color: var(--track-accent); opacity: 1; }
.back-to-top { position: absolute; top: -25px; left: 50%; transform: translateX(-50%); width: 50px; height: 50px; background-color: var(--track-accent); color: var(--primary-bg); display: flex; justify-content: center; align-items: center; border-radius: 50%; font-size: 1.2rem; text-decoration: none; box-shadow: 0 0 10px rgba(0,0,0,.3); transition: all .3s ease; }
.back-to-top:hover { background-color: var(--hover-color); transform: translateX(-50%) translateY(-5px); }

/* Per-track accents */
body.track-frontend { --track-accent: #61dafb; }
body.track-ai { --track-accent: #a78bfa; }
body.track-fullstack { --track-accent: #fbbf24; }

/* Responsive */
@media screen and (max-width: 992px) {
    .hero h1 { font-size: 2.6rem; }
    .about-container { grid-template-columns: 1fr; }
    .about-image { order: -1; max-width: 500px; margin: 0 auto; }
}
@media screen and (max-width: 768px) {
    .menu-toggle { display: block; }
    .nav-links { position: fixed; top: 80px; left: -100%; flex-direction: column; background-color: var(--secondary-bg); width: 100%; text-align: center; transition: .3s; box-shadow: 0 10px 10px rgba(0,0,0,.1); padding: 10px 0; }
    .nav-links.active { left: 0; }
    .nav-links li { margin: 15px 0; }
    .hero h1 { font-size: 2.2rem; }
    .portfolio-grid { grid-template-columns: 1fr; max-width: 440px; margin: 0 auto; }
    .track-bar { display: none; }
}
@media screen and (max-width: 576px) {
    .section { padding: 60px 0; }
    .container { padding: 0 20px; }
    .hero h1 { font-size: 1.9rem; }
    .hero p { font-size: 1rem; }
    .hero-buttons { flex-direction: column; gap: 10px; }
    .btn { width: 100%; text-align: center; }
    .contact-icons { gap: 20px; }
}