/* ══════════════════════════════════════════════════
   DESIGN SYSTEM — Yash Karle Portfolio
   ══════════════════════════════════════════════════ */

@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700&family=Outfit:wght@400;500;600;700;800&family=JetBrains+Mono:wght@400;500&display=swap');

/* ── Tokens ────────────────────────────────────── */
:root {
  --bg-primary:    #060b18;
  --bg-secondary:  #0c1225;
  --bg-card:       rgba(15, 23, 50, .55);
  --bg-card-hover: rgba(22, 33, 68, .6);

  --text-primary:   #e8ecf4;
  --text-secondary: #8892a8;
  --text-muted:     #5a6480;

  --accent:         #6366f1;
  --accent-light:   #818cf8;
  --accent-glow:    rgba(99,102,241,.25);
  --gradient-start:  #6366f1;
  --gradient-end:    #a855f7;

  --border:         rgba(99,102,241,.12);
  --border-hover:   rgba(99,102,241,.3);

  --glass-blur:     18px;
  --radius-sm:      8px;
  --radius-md:      14px;
  --radius-lg:      20px;
  --radius-xl:      28px;

  --shadow-card:    0 4px 30px rgba(0,0,0,.35);
  --shadow-glow:    0 0 40px var(--accent-glow);

  --transition:     .3s cubic-bezier(.4,0,.2,1);
  --max-width:      1200px;
}

/* ── Reset ─────────────────────────────────────── */
*,*::before,*::after{box-sizing:border-box;margin:0;padding:0}
html{scroll-behavior:smooth;font-size:16px;-webkit-font-smoothing:antialiased}
body{
  font-family:'Inter',system-ui,sans-serif;
  background:var(--bg-primary);
  color:var(--text-primary);
  line-height:1.7;
  overflow-x:hidden;
}
a{color:inherit;text-decoration:none}
ul,ol{list-style:none}
img{max-width:100%;display:block}
button{font-family:inherit;cursor:pointer;border:none;background:none}

/* ── Utility ───────────────────────────────────── */
.container{max-width:var(--max-width);margin:0 auto;padding:0 24px}
.section-label{
  font-family:'Outfit',sans-serif;
  font-size:.8rem;
  font-weight:600;
  letter-spacing:3px;
  text-transform:uppercase;
  background:linear-gradient(135deg,var(--gradient-start),var(--gradient-end));
  -webkit-background-clip:text;-webkit-text-fill-color:transparent;
  margin-bottom:10px;
}
.section-title{
  font-family:'Outfit',sans-serif;
  font-size:clamp(1.8rem,4vw,2.6rem);
  font-weight:700;
  margin-bottom:16px;
  color:var(--text-primary);
}
.section-subtitle{
  color:var(--text-secondary);
  max-width:640px;
  font-size:1.05rem;
  line-height:1.75;
}

/* ── Scroll reveal ─────────────────────────────── */
.reveal{opacity:0;transform:translateY(30px);transition:opacity .7s var(--transition),transform .7s var(--transition)}
.reveal.visible{opacity:1;transform:translateY(0)}

/* ══════════════════════════════════════════════════
   NAVIGATION
   ══════════════════════════════════════════════════ */
.navbar{
  position:fixed;top:0;left:0;width:100%;z-index:1000;
  padding:16px 0;
  transition:background var(--transition),box-shadow var(--transition),padding var(--transition);
}
.navbar.scrolled{
  background:rgba(6,11,24,.85);
  backdrop-filter:blur(var(--glass-blur));
  -webkit-backdrop-filter:blur(var(--glass-blur));
  box-shadow:0 1px 30px rgba(0,0,0,.4);
  padding:10px 0;
}
.nav-inner{
  display:flex;align-items:center;justify-content:space-between;
  max-width:var(--max-width);margin:0 auto;padding:0 24px;
}
.nav-logo{
  font-family:'Outfit',sans-serif;
  font-weight:700;font-size:1.35rem;
  background:linear-gradient(135deg,var(--gradient-start),var(--gradient-end));
  -webkit-background-clip:text;-webkit-text-fill-color:transparent;
}
.nav-links{display:flex;gap:32px}
.nav-links a{
  font-size:.9rem;font-weight:500;color:var(--text-secondary);
  position:relative;transition:color var(--transition);
}
.nav-links a::after{
  content:'';position:absolute;bottom:-4px;left:0;width:0;height:2px;
  background:linear-gradient(90deg,var(--gradient-start),var(--gradient-end));
  transition:width var(--transition);
}
.nav-links a:hover,
.nav-links a.active{color:var(--text-primary)}
.nav-links a:hover::after,
.nav-links a.active::after{width:100%}

/* hamburger */
.hamburger{display:none;flex-direction:column;gap:5px;padding:4px}
.hamburger span{display:block;width:24px;height:2px;background:var(--text-primary);border-radius:2px;transition:var(--transition)}

/* ══════════════════════════════════════════════════
   HERO
   ══════════════════════════════════════════════════ */
.hero{
  min-height:100vh;display:flex;align-items:center;
  position:relative;overflow:hidden;
  padding:120px 0 80px;
}
.hero-bg{
  position:absolute;inset:0;z-index:0;
  background:
    radial-gradient(ellipse 80% 60% at 50% -10%, rgba(99,102,241,.15), transparent),
    radial-gradient(ellipse 60% 50% at 80% 80%, rgba(168,85,247,.1), transparent);
}
.hero-content{position:relative;z-index:1;max-width:720px}
.hero-badge{
  display:inline-flex;align-items:center;gap:8px;
  padding:6px 16px;border-radius:999px;
  background:var(--bg-card);border:1px solid var(--border);
  font-size:.82rem;font-weight:500;color:var(--accent-light);
  margin-bottom:24px;
}
.hero-badge .dot{width:8px;height:8px;border-radius:50%;background:var(--accent);animation:pulse 2s infinite}
@keyframes pulse{0%,100%{opacity:1}50%{opacity:.4}}

.hero h1{
  font-family:'Outfit',sans-serif;
  font-size:clamp(2.4rem,6vw,4rem);
  font-weight:800;line-height:1.15;
  margin-bottom:12px;
}
.hero h1 .gradient{
  background:linear-gradient(135deg,var(--gradient-start),var(--gradient-end));
  -webkit-background-clip:text;-webkit-text-fill-color:transparent;
}
.hero .tagline{
  font-size:1.15rem;color:var(--text-secondary);line-height:1.8;
  margin-bottom:32px;max-width:560px;
}
.hero-cta{display:flex;flex-wrap:wrap;gap:14px;margin-bottom:40px}

/* ── Buttons ───────────────────────────────────── */
.btn{
  display:inline-flex;align-items:center;gap:8px;
  padding:13px 28px;border-radius:var(--radius-sm);
  font-weight:600;font-size:.92rem;
  transition:all var(--transition);
}
.btn-primary{
  background:linear-gradient(135deg,var(--gradient-start),var(--gradient-end));
  color:#fff;
  box-shadow:0 4px 20px var(--accent-glow);
}
.btn-primary:hover{transform:translateY(-2px);box-shadow:var(--shadow-glow)}
.btn-secondary{
  background:var(--bg-card);
  border:1px solid var(--border);
  color:var(--text-primary);
}
.btn-secondary:hover{border-color:var(--border-hover);background:var(--bg-card-hover)}

/* tool badges */
.tool-badges{display:flex;flex-wrap:wrap;gap:10px}
.tool-badge{
  padding:6px 16px;border-radius:999px;
  background:var(--bg-card);border:1px solid var(--border);
  font-size:.78rem;font-weight:500;color:var(--text-secondary);
  transition:all var(--transition);
}
.tool-badge:hover{border-color:var(--border-hover);color:var(--accent-light)}

/* ══════════════════════════════════════════════════
   ABOUT
   ══════════════════════════════════════════════════ */
#about{padding:100px 0}
.about-grid{
  display:grid;grid-template-columns:1fr 1fr;gap:48px;
  margin-top:40px;
}
.about-text p{color:var(--text-secondary);margin-bottom:16px;font-size:1.02rem}
.about-text p strong{color:var(--text-primary)}
.about-highlights{display:flex;flex-direction:column;gap:20px}
.highlight-card{
  padding:22px 26px;border-radius:var(--radius-md);
  background:var(--bg-card);border:1px solid var(--border);
  backdrop-filter:blur(var(--glass-blur));
  transition:all var(--transition);
}
.highlight-card:hover{border-color:var(--border-hover);transform:translateY(-3px);box-shadow:var(--shadow-card)}
.highlight-card .icon{font-size:1.5rem;margin-bottom:8px}
.highlight-card h4{font-family:'Outfit',sans-serif;font-weight:600;font-size:1rem;margin-bottom:4px}
.highlight-card p{font-size:.88rem;color:var(--text-secondary);line-height:1.6}

/* certs */
.cert-list{margin-top:32px}
.cert-list h3{font-family:'Outfit',sans-serif;font-size:1.1rem;font-weight:600;margin-bottom:14px}
.cert-item{
  display:flex;gap:12px;align-items:flex-start;
  padding:10px 0;border-bottom:1px solid var(--border);
  font-size:.9rem;color:var(--text-secondary);
}
.cert-item:last-child{border-bottom:none}
.cert-item .year{color:var(--accent-light);font-weight:600;white-space:nowrap;font-size:.82rem}

/* ══════════════════════════════════════════════════
   PROJECTS
   ══════════════════════════════════════════════════ */
#projects{padding:100px 0}
.projects-header{text-align:center;margin-bottom:56px}
.projects-header .section-subtitle{margin:0 auto}

/* filter tabs */
.project-filters{
  display:flex;justify-content:center;gap:10px;
  margin-bottom:48px;flex-wrap:wrap;
}
.filter-btn{
  padding:8px 20px;border-radius:999px;
  font-size:.85rem;font-weight:500;
  background:var(--bg-card);border:1px solid var(--border);
  color:var(--text-secondary);
  transition:all var(--transition);
}
.filter-btn:hover,.filter-btn.active{
  background:linear-gradient(135deg,var(--gradient-start),var(--gradient-end));
  color:#fff;border-color:transparent;
}

/* project cards */
.projects-grid{
  display:grid;
  grid-template-columns:repeat(auto-fill,minmax(360px,1fr));
  gap:28px;
}
.project-card{
  background:var(--bg-card);
  border:1px solid var(--border);
  border-radius:var(--radius-lg);
  backdrop-filter:blur(var(--glass-blur));
  overflow:hidden;
  transition:all var(--transition);
  cursor:pointer;
}
.project-card:hover{
  border-color:var(--border-hover);
  transform:translateY(-6px);
  box-shadow:var(--shadow-card);
}
.card-header{
  padding:28px 28px 0;
}
.card-category{
  display:inline-block;
  padding:4px 12px;border-radius:999px;
  font-size:.72rem;font-weight:600;letter-spacing:1px;text-transform:uppercase;
  background:var(--accent-glow);color:var(--accent-light);
  margin-bottom:14px;
}
.card-header h3{
  font-family:'Outfit',sans-serif;font-size:1.2rem;font-weight:700;
  margin-bottom:8px;
}
.card-header p{
  font-size:.9rem;color:var(--text-secondary);line-height:1.65;
  margin-bottom:16px;
}
.card-tools{
  display:flex;flex-wrap:wrap;gap:6px;
  padding:0 28px;margin-bottom:20px;
}
.card-tools span{
  padding:3px 10px;border-radius:999px;
  font-size:.7rem;font-weight:500;
  background:rgba(99,102,241,.08);color:var(--accent-light);
  border:1px solid rgba(99,102,241,.15);
}
.card-metrics{
  display:grid;grid-template-columns:1fr 1fr;
  border-top:1px solid var(--border);
}
.card-metric{
  padding:16px 28px;
  border-right:1px solid var(--border);
}
.card-metric:last-child{border-right:none}
.card-metric .label{font-size:.7rem;text-transform:uppercase;letter-spacing:1px;color:var(--text-muted);margin-bottom:2px}
.card-metric .value{font-family:'Outfit',sans-serif;font-weight:700;font-size:1rem;color:var(--accent-light)}

/* expanded project detail */
.project-detail{
  display:none;
  padding:0 28px 28px;
  animation:fadeSlide .4s ease;
}
.project-card.expanded .project-detail{display:block}
@keyframes fadeSlide{from{opacity:0;transform:translateY(-10px)}to{opacity:1;transform:none}}

.detail-section{margin-bottom:20px}
.detail-section h4{
  font-family:'Outfit',sans-serif;font-size:.92rem;font-weight:600;
  color:var(--accent-light);margin-bottom:8px;
  display:flex;align-items:center;gap:8px;
}
.detail-section p,
.detail-section li{font-size:.88rem;color:var(--text-secondary);line-height:1.7}
.detail-section ul{padding-left:18px}
.detail-section ul li{position:relative;padding-left:14px;margin-bottom:6px}
.detail-section ul li::before{
  content:'▸';position:absolute;left:0;color:var(--accent);
}
.card-expand-btn{
  display:flex;align-items:center;justify-content:center;gap:6px;
  width:100%;padding:14px;
  border-top:1px solid var(--border);
  font-size:.82rem;font-weight:500;color:var(--text-muted);
  transition:color var(--transition);
}
.card-expand-btn:hover{color:var(--accent-light)}
.card-expand-btn .arrow{transition:transform var(--transition)}
.project-card.expanded .card-expand-btn .arrow{transform:rotate(180deg)}

/* ══════════════════════════════════════════════════
   OTHER PROJECTS (secondary)
   ══════════════════════════════════════════════════ */
.other-projects{margin-top:64px;text-align:center}
.other-projects h3{font-family:'Outfit',sans-serif;font-size:1.25rem;font-weight:600;margin-bottom:8px}
.other-projects>p{color:var(--text-secondary);font-size:.95rem;margin-bottom:28px}
.other-grid{
  display:grid;grid-template-columns:repeat(auto-fill,minmax(300px,1fr));
  gap:22px;text-align:left;
}
.other-card{
  padding:24px;border-radius:var(--radius-md);
  background:var(--bg-card);border:1px solid var(--border);
  backdrop-filter:blur(var(--glass-blur));
  transition:all var(--transition);
}
.other-card:hover{border-color:var(--border-hover);transform:translateY(-3px)}
.other-card h4{font-family:'Outfit',sans-serif;font-weight:600;margin-bottom:6px;font-size:1rem}
.other-card p{font-size:.85rem;color:var(--text-secondary);line-height:1.6;margin-bottom:12px}
.other-card .card-tools{padding:0}

/* ══════════════════════════════════════════════════
   RESUME
   ══════════════════════════════════════════════════ */
#resume{
  padding:100px 0;text-align:center;
}
.resume-box{
  max-width:560px;margin:40px auto 0;
  padding:48px;border-radius:var(--radius-lg);
  background:var(--bg-card);border:1px solid var(--border);
  backdrop-filter:blur(var(--glass-blur));
}
.resume-box .icon{font-size:3rem;margin-bottom:16px}
.resume-box p{color:var(--text-secondary);margin-bottom:28px;font-size:1rem}
.resume-box .btn{font-size:1rem;padding:16px 36px}

/* ══════════════════════════════════════════════════
   CONTACT
   ══════════════════════════════════════════════════ */
#contact{padding:100px 0}
.contact-inner{text-align:center}
.contact-links{
  display:flex;justify-content:center;gap:24px;
  margin-top:40px;flex-wrap:wrap;
}
.contact-card{
  display:flex;align-items:center;gap:14px;
  padding:22px 32px;border-radius:var(--radius-md);
  background:var(--bg-card);border:1px solid var(--border);
  backdrop-filter:blur(var(--glass-blur));
  transition:all var(--transition);
  text-decoration:none;
}
.contact-card:hover{
  border-color:var(--border-hover);transform:translateY(-4px);
  box-shadow:var(--shadow-card);
}
.contact-card .c-icon{
  width:48px;height:48px;border-radius:var(--radius-sm);
  display:flex;align-items:center;justify-content:center;
  background:var(--accent-glow);font-size:1.3rem;
}
.contact-card .c-label{font-size:.78rem;color:var(--text-muted);text-transform:uppercase;letter-spacing:1px}
.contact-card .c-value{font-weight:600;font-size:.95rem;color:var(--text-primary)}

/* ══════════════════════════════════════════════════
   FOOTER
   ══════════════════════════════════════════════════ */
.footer{
  padding:32px 0;text-align:center;
  border-top:1px solid var(--border);
  font-size:.82rem;color:var(--text-muted);
}

/* ══════════════════════════════════════════════════
   RESPONSIVE
   ══════════════════════════════════════════════════ */
@media(max-width:900px){
  .about-grid{grid-template-columns:1fr}
  .projects-grid{grid-template-columns:1fr}
  .other-grid{grid-template-columns:1fr}
}
@media(max-width:768px){
  .nav-links{
    position:fixed;top:0;right:-100%;width:70%;max-width:300px;height:100vh;
    flex-direction:column;gap:0;
    background:var(--bg-secondary);
    padding:80px 32px 32px;
    transition:right var(--transition);
    box-shadow:-4px 0 30px rgba(0,0,0,.5);
  }
  .nav-links.open{right:0}
  .nav-links a{padding:14px 0;border-bottom:1px solid var(--border);font-size:1rem}
  .hamburger{display:flex}
  .hero h1{font-size:clamp(2rem,8vw,2.8rem)}
  .contact-links{flex-direction:column;align-items:center}
  .projects-grid{grid-template-columns:1fr}
}

/* ── Overlay for mobile nav ────────────────────── */
.nav-overlay{
  position:fixed;inset:0;background:rgba(0,0,0,.5);z-index:999;
  opacity:0;pointer-events:none;transition:opacity var(--transition);
}
.nav-overlay.open{opacity:1;pointer-events:auto}