/* ============================================================
   Utsav Shah — Portfolio
   Design: deep-space dark theme, dual research/engineer modes
   ============================================================ */

:root {
  /* base palette */
  --bg: #060814;
  --bg-soft: #0b0f24;
  --surface: #0f1530;
  --surface-2: #141b3d;
  --border: rgba(140, 160, 255, 0.12);
  --border-strong: rgba(140, 160, 255, 0.28);

  --text: #eef1ff;
  --text-dim: #aab2d5;
  --text-faint: #6c7599;

  /* accents — research mode (default) */
  --accent: #7c5cff;
  --accent-2: #22d3ee;
  --accent-glow: rgba(124, 92, 255, 0.5);
  --grad: linear-gradient(120deg, #7c5cff 0%, #22d3ee 100%);

  --radius: 18px;
  --radius-sm: 12px;
  --maxw: 1180px;
  --ease: cubic-bezier(0.22, 1, 0.36, 1);
  --font-display: "Space Grotesk", sans-serif;
  --font-body: "Inter", sans-serif;
  --font-mono: "JetBrains Mono", monospace;
}

/* engineer mode swaps the accent toward a warmer green/amber */
body[data-mode="engineer"] {
  --accent: #34d399;
  --accent-2: #fbbf24;
  --accent-glow: rgba(52, 211, 153, 0.45);
  --grad: linear-gradient(120deg, #34d399 0%, #fbbf24 100%);
}

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

html { scroll-behavior: smooth; scroll-padding-top: 90px; }

body {
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-body);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

#bg-canvas {
  position: fixed;
  inset: 0;
  z-index: 0;
  opacity: 0.7;
  pointer-events: none;
}

main, .nav, .footer { position: relative; z-index: 1; }

a { color: inherit; text-decoration: none; }
strong { color: var(--text); font-weight: 600; }
.acc { color: var(--accent-2); font-weight: 600; }

/* ---------- scroll progress ---------- */
.scroll-progress {
  position: fixed; top: 0; left: 0; height: 3px; width: 0%;
  background: var(--grad); z-index: 100;
  box-shadow: 0 0 12px var(--accent-glow);
  transition: width 0.1s linear;
}

/* ---------- buttons ---------- */
.btn {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 12px 22px; border-radius: 999px;
  font-weight: 600; font-size: 0.95rem;
  cursor: pointer; border: 1px solid transparent;
  transition: transform 0.25s var(--ease), box-shadow 0.25s var(--ease), background 0.25s, border-color 0.25s;
  white-space: nowrap;
}
.btn--primary {
  background: var(--grad); color: #06070f;
  box-shadow: 0 8px 30px var(--accent-glow);
}
.btn--primary:hover { transform: translateY(-3px); box-shadow: 0 14px 40px var(--accent-glow); }
.btn--ghost {
  background: rgba(255,255,255,0.03); color: var(--text);
  border-color: var(--border-strong);
}
.btn--ghost:hover { transform: translateY(-3px); border-color: var(--accent); color: var(--accent); }
.btn--lg { padding: 16px 30px; font-size: 1.05rem; }

/* ---------- navbar ---------- */
.nav {
  position: fixed; top: 0; left: 0; right: 0;
  display: flex; align-items: center; justify-content: space-between;
  gap: 18px; padding: 16px clamp(18px, 5vw, 48px);
  backdrop-filter: blur(14px);
  background: rgba(6, 8, 20, 0.55);
  border-bottom: 1px solid transparent;
  transition: background 0.3s, border-color 0.3s, padding 0.3s;
}
.nav.is-scrolled {
  background: rgba(6, 8, 20, 0.85);
  border-bottom-color: var(--border);
  padding-top: 12px; padding-bottom: 12px;
}
.nav__brand { display: flex; align-items: center; gap: 12px; font-weight: 700; }
.nav__logo {
  display: grid; place-items: center;
  width: 38px; height: 38px; border-radius: 11px;
  background: var(--grad); color: #06070f;
  font-family: var(--font-display); font-weight: 700; font-size: 0.95rem;
  box-shadow: 0 6px 20px var(--accent-glow);
}
.nav__name { font-family: var(--font-display); letter-spacing: 0.2px; }
.nav__links { display: flex; gap: 4px; }
.nav__links a {
  padding: 8px 14px; border-radius: 999px;
  color: var(--text-dim); font-size: 0.92rem; font-weight: 500;
  transition: color 0.2s, background 0.2s;
}
.nav__links a:hover, .nav__links a.is-active { color: var(--text); background: rgba(255,255,255,0.05); }
.nav__actions { display: flex; align-items: center; gap: 12px; }

/* mode toggle */
.mode-toggle {
  position: relative; display: flex;
  background: var(--surface); border: 1px solid var(--border);
  border-radius: 999px; padding: 4px;
}
.mode-toggle__btn {
  position: relative; z-index: 2;
  background: none; border: none; cursor: pointer;
  color: var(--text-dim); font-family: var(--font-body);
  font-size: 0.8rem; font-weight: 600; padding: 7px 14px;
  border-radius: 999px; transition: color 0.3s; white-space: nowrap;
}
.mode-toggle__btn.is-active { color: #06070f; }
.mode-toggle__pill {
  position: absolute; z-index: 1; top: 4px; left: 4px;
  height: calc(100% - 8px); border-radius: 999px;
  background: var(--grad); box-shadow: 0 4px 16px var(--accent-glow);
  transition: transform 0.35s var(--ease), width 0.35s var(--ease);
}
.nav__resume { padding: 9px 18px; font-size: 0.88rem; }

.nav__burger { display: none; background: none; border: none; cursor: pointer; flex-direction: column; gap: 5px; padding: 6px; }
.nav__burger span { width: 24px; height: 2px; background: var(--text); border-radius: 2px; transition: 0.3s; }

/* ---------- hero ---------- */
.hero {
  min-height: 100vh; display: flex; flex-direction: column; justify-content: center;
  padding: 130px clamp(18px, 5vw, 48px) 60px;
  max-width: var(--maxw); margin: 0 auto;
}
.hero__inner {
  display: grid; grid-template-columns: 1.25fr 0.85fr;
  gap: clamp(30px, 6vw, 80px); align-items: center;
}
.hero__eyebrow {
  display: inline-flex; align-items: center; gap: 9px;
  font-family: var(--font-mono); font-size: 0.85rem; color: var(--text-dim);
  background: rgba(255,255,255,0.03); border: 1px solid var(--border);
  padding: 7px 14px; border-radius: 999px; margin-bottom: 22px;
}
.status-dot {
  width: 8px; height: 8px; border-radius: 50%; background: var(--accent);
  box-shadow: 0 0 0 0 var(--accent-glow); animation: pulse 2.2s infinite;
}
@keyframes pulse {
  0% { box-shadow: 0 0 0 0 var(--accent-glow); }
  70% { box-shadow: 0 0 0 10px rgba(0,0,0,0); }
  100% { box-shadow: 0 0 0 0 rgba(0,0,0,0); }
}
.hero__title {
  font-family: var(--font-display); font-weight: 700;
  font-size: clamp(3rem, 8vw, 5.6rem); line-height: 1.02;
  letter-spacing: -2px; margin-bottom: 12px;
  background: linear-gradient(180deg, #fff 30%, #aab2d5 100%);
  -webkit-background-clip: text; background-clip: text; -webkit-text-fill-color: transparent;
}
.hero__role { font-size: clamp(1.2rem, 3vw, 1.7rem); font-weight: 600; margin-bottom: 22px; min-height: 1.6em; }
.rotator { background: var(--grad); -webkit-background-clip: text; background-clip: text; -webkit-text-fill-color: transparent; }
.hero__lede { color: var(--text-dim); font-size: 1.08rem; max-width: 600px; margin-bottom: 18px; }

.hero__pitch { margin-bottom: 30px; max-width: 600px; min-height: 60px; position: relative; }
.hero__pitch-text {
  color: var(--text-dim); font-size: 1rem;
  padding: 14px 18px; border-left: 3px solid var(--accent);
  background: rgba(255,255,255,0.025); border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  display: none;
}
.hero__pitch-text.is-visible { display: block; animation: fadeUp 0.5s var(--ease); }

.hero__cta { display: flex; gap: 14px; flex-wrap: wrap; margin-bottom: 26px; }
.hero__socials { display: flex; align-items: center; gap: 12px; color: var(--text-faint); font-size: 0.95rem; }
.hero__socials a { color: var(--text-dim); font-weight: 500; transition: color 0.2s; }
.hero__socials a:hover { color: var(--accent); }

/* hero photo */
.hero__visual { display: flex; justify-content: center; }
.hero__photo-wrap { position: relative; width: min(340px, 78vw); aspect-ratio: 1; }
.hero__photo-glow {
  position: absolute; inset: -12%; border-radius: 50%;
  background: var(--grad); filter: blur(48px); opacity: 0.4;
  animation: float 7s ease-in-out infinite;
}
.hero__photo {
  position: relative; width: 100%; height: 100%; object-fit: cover;
  border-radius: 28px; border: 1px solid var(--border-strong);
  box-shadow: 0 30px 80px rgba(0,0,0,0.6);
}
.hero__badge {
  position: absolute; z-index: 3;
  font-family: var(--font-mono); font-size: 0.78rem; font-weight: 500;
  color: var(--text); background: rgba(15, 21, 48, 0.9);
  backdrop-filter: blur(8px); border: 1px solid var(--border-strong);
  padding: 8px 13px; border-radius: 999px; white-space: nowrap;
  box-shadow: 0 8px 24px rgba(0,0,0,0.4);
  animation: float 6s ease-in-out infinite;
}
.hero__badge--1 { top: 6%; left: -14%; animation-delay: 0s; }
.hero__badge--2 { bottom: 14%; right: -18%; animation-delay: 1.2s; }
.hero__badge--3 { bottom: -4%; left: 6%; animation-delay: 2.4s; }
@keyframes float { 0%,100% { transform: translateY(0); } 50% { transform: translateY(-12px); } }

.hero__scroll {
  display: inline-flex; align-items: center; gap: 8px; margin-top: 50px;
  align-self: center; color: var(--text-faint); font-family: var(--font-mono); font-size: 0.8rem;
}
.hero__scroll span {
  width: 22px; height: 36px; border: 2px solid var(--border-strong); border-radius: 12px; position: relative;
}
.hero__scroll span::after {
  content: ""; position: absolute; top: 7px; left: 50%; transform: translateX(-50%);
  width: 4px; height: 7px; border-radius: 2px; background: var(--accent);
  animation: scrolldot 1.8s infinite;
}
@keyframes scrolldot { 0% { opacity: 0; top: 7px; } 40% { opacity: 1; } 80% { opacity: 0; top: 18px; } 100% { opacity: 0; } }

/* ---------- metrics ---------- */
.metrics {
  max-width: var(--maxw); margin: 0 auto; padding: 0 clamp(18px, 5vw, 48px) 40px;
  display: grid; grid-template-columns: repeat(4, 1fr); gap: 18px;
}
.metric {
  text-align: center; padding: 28px 16px;
  background: linear-gradient(180deg, var(--surface) 0%, rgba(15,21,48,0.4) 100%);
  border: 1px solid var(--border); border-radius: var(--radius);
}
.metric__num {
  display: block; font-family: var(--font-display); font-weight: 700;
  font-size: clamp(2rem, 4vw, 2.8rem);
  background: var(--grad); -webkit-background-clip: text; background-clip: text; -webkit-text-fill-color: transparent;
}
.metric__label { color: var(--text-faint); font-size: 0.85rem; font-family: var(--font-mono); }

/* ---------- generic section ---------- */
.section { max-width: var(--maxw); margin: 0 auto; padding: clamp(60px, 9vw, 120px) clamp(18px, 5vw, 48px); }
.section__head { margin-bottom: 50px; }
.section__kicker {
  display: inline-block; font-family: var(--font-mono); font-size: 0.82rem;
  color: var(--accent-2); letter-spacing: 1px; margin-bottom: 14px;
}
.section__title {
  font-family: var(--font-display); font-weight: 700;
  font-size: clamp(1.9rem, 4.5vw, 3rem); letter-spacing: -1px; line-height: 1.1;
}
.section__sub { color: var(--text-dim); margin-top: 14px; max-width: 620px; font-size: 1.05rem; }

/* ---------- about ---------- */
.about { display: grid; grid-template-columns: 1.4fr 1fr; gap: 40px; align-items: start; }
.about__bio p { color: var(--text-dim); margin-bottom: 18px; font-size: 1.05rem; }
.about__interests { display: flex; flex-wrap: wrap; gap: 10px; margin-top: 26px; }
.tag {
  font-family: var(--font-mono); font-size: 0.82rem; padding: 7px 14px;
  border-radius: 999px; border: 1px solid var(--border-strong);
  color: var(--text-dim); background: rgba(255,255,255,0.02);
  transition: 0.25s var(--ease);
}
.tag:hover { color: var(--accent); border-color: var(--accent); transform: translateY(-2px); }

.about__card {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 28px;
}
.about__card h3 { font-family: var(--font-display); margin-bottom: 18px; font-size: 1.15rem; }
.about__list { list-style: none; }
.about__list li {
  display: flex; justify-content: space-between; gap: 14px;
  padding: 12px 0; border-bottom: 1px solid var(--border); font-size: 0.92rem;
}
.about__list li:last-child { border-bottom: none; }
.about__list span { color: var(--text-faint); }
.about__list strong { text-align: right; }
.about__honor {
  display: flex; align-items: center; gap: 14px; margin-top: 20px; padding-top: 20px;
  border-top: 1px solid var(--border);
}
.hex { font-size: 1.8rem; }
.about__honor strong { display: block; font-family: var(--font-display); }
.about__honor small { color: var(--text-faint); }

/* ---------- timeline ---------- */
.timeline { position: relative; padding-left: 6px; }
.timeline::before {
  content: ""; position: absolute; left: 7px; top: 6px; bottom: 6px; width: 2px;
  background: linear-gradient(180deg, var(--accent), transparent);
}
.tl { position: relative; padding-left: 38px; padding-bottom: 46px; }
.tl:last-child { padding-bottom: 0; }
.tl__dot {
  position: absolute; left: 0; top: 5px; width: 16px; height: 16px; border-radius: 50%;
  background: var(--bg); border: 3px solid var(--accent); box-shadow: 0 0 0 4px rgba(124,92,255,0.12);
}
.tl__meta { display: flex; align-items: center; gap: 12px; margin-bottom: 6px; }
.tl__date { font-family: var(--font-mono); font-size: 0.82rem; color: var(--accent-2); }
.tl__tag--feature {
  font-size: 0.7rem; font-weight: 700; text-transform: uppercase; letter-spacing: 0.5px;
  background: var(--grad); color: #06070f; padding: 3px 9px; border-radius: 999px;
}
.tl__body { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); padding: 24px 26px; transition: 0.3s var(--ease); }
.tl:hover .tl__body { border-color: var(--border-strong); transform: translateX(4px); }
.tl__body h3 { font-family: var(--font-display); font-size: 1.25rem; margin-bottom: 4px; }
.tl__org { color: var(--text-dim); font-size: 0.92rem; margin-bottom: 14px; }
.tl__desc { color: var(--text-dim); margin-bottom: 14px; }
.tl__points { list-style: none; margin-bottom: 16px; }
.tl__points li { color: var(--text-dim); padding-left: 22px; position: relative; margin-bottom: 10px; font-size: 0.97rem; }
.tl__points li::before { content: "▹"; position: absolute; left: 0; color: var(--accent); }
.tl__chips { display: flex; flex-wrap: wrap; gap: 8px; }
.tl__chips span, .proj__stack span, .skillcard__tags span {
  font-family: var(--font-mono); font-size: 0.74rem; padding: 5px 11px; border-radius: 7px;
  background: rgba(124,92,255,0.08); border: 1px solid var(--border); color: var(--text-dim);
}

/* ---------- projects ---------- */
.projects { display: grid; grid-template-columns: repeat(3, 1fr); gap: 22px; }
.proj {
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 26px; display: flex; flex-direction: column; transition: 0.3s var(--ease); position: relative; overflow: hidden;
}
.proj::before {
  content: ""; position: absolute; inset: 0; opacity: 0; transition: opacity 0.3s;
  background: radial-gradient(400px circle at var(--mx,50%) var(--my,0%), rgba(124,92,255,0.1), transparent 60%);
}
.proj:hover { transform: translateY(-6px); border-color: var(--border-strong); box-shadow: 0 20px 50px rgba(0,0,0,0.4); }
.proj:hover::before { opacity: 1; }
.proj__top { display: flex; align-items: center; justify-content: space-between; margin-bottom: 14px; }
.proj__icon { font-size: 1.8rem; }
.proj__type { font-family: var(--font-mono); font-size: 0.72rem; color: var(--accent-2); }
.proj h3 { font-family: var(--font-display); font-size: 1.18rem; margin-bottom: 10px; }
.proj > p { color: var(--text-dim); font-size: 0.95rem; margin-bottom: 16px; }
.proj__impact { list-style: none; margin-bottom: 18px; }
.proj__impact li { color: var(--text-dim); font-size: 0.88rem; padding: 5px 0 5px 18px; position: relative; }
.proj__impact li::before { content: ""; position: absolute; left: 0; top: 13px; width: 7px; height: 7px; border-radius: 50%; background: var(--accent); }
.proj__stack { display: flex; flex-wrap: wrap; gap: 7px; margin-top: auto; }
.proj--cta { align-items: flex-start; justify-content: center; background: linear-gradient(150deg, var(--surface-2), var(--surface)); }
.proj--cta h3 { font-size: 1.4rem; }
.proj--cta p { margin-bottom: 20px; }

/* ---------- skills ---------- */
.skills { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; }
.skillcard { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); padding: 24px; transition: 0.3s var(--ease); }
.skillcard:hover { border-color: var(--border-strong); transform: translateY(-4px); }
.skillcard h3 { font-family: var(--font-display); font-size: 1.05rem; margin-bottom: 16px; color: var(--accent-2); }
.skillcard__tags { display: flex; flex-wrap: wrap; gap: 8px; }

/* ---------- teaching / two col ---------- */
.two-col { display: grid; grid-template-columns: 1fr 1fr; gap: 22px; margin-bottom: 26px; }
.panel { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); padding: 28px; }
.panel h3 { font-family: var(--font-display); font-size: 1.2rem; }
.panel__org { color: var(--accent-2); font-family: var(--font-mono); font-size: 0.82rem; margin: 4px 0 16px; }
.panel ul { list-style: none; }
.panel li { color: var(--text-dim); padding-left: 20px; position: relative; margin-bottom: 11px; font-size: 0.96rem; }
.panel li::before { content: "▹"; position: absolute; left: 0; color: var(--accent); }
.pub {
  display: flex; gap: 18px; align-items: flex-start;
  background: linear-gradient(120deg, rgba(124,92,255,0.07), rgba(34,211,238,0.05));
  border: 1px solid var(--border); border-radius: var(--radius); padding: 24px 26px;
}
.pub__icon { font-size: 1.8rem; }
.pub strong { color: var(--accent-2); font-family: var(--font-mono); font-size: 0.82rem; display: block; margin-bottom: 6px; }
.pub p { color: var(--text-dim); font-size: 0.96rem; }

/* ---------- awards ---------- */
.awards { display: grid; grid-template-columns: repeat(4, 1fr); gap: 18px; margin-bottom: 50px; }
.award { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); padding: 26px; transition: 0.3s var(--ease); }
.award:hover { transform: translateY(-4px); border-color: var(--border-strong); }
.award__amt {
  display: block; font-family: var(--font-display); font-weight: 700; font-size: 2rem; margin-bottom: 10px;
  background: var(--grad); -webkit-background-clip: text; background-clip: text; -webkit-text-fill-color: transparent;
}
.award p { color: var(--text-dim); font-size: 0.9rem; }
.hobbies h3 { font-family: var(--font-display); font-size: 1.2rem; margin-bottom: 18px; }
.hobbies__row { display: flex; flex-wrap: wrap; gap: 12px; }
.hobby {
  background: rgba(255,255,255,0.03); border: 1px solid var(--border); border-radius: 999px;
  padding: 10px 18px; color: var(--text-dim); font-size: 0.92rem; transition: 0.25s var(--ease);
}
.hobby:hover { transform: translateY(-3px); border-color: var(--accent); color: var(--text); }

/* ---------- contact ---------- */
.section--contact { text-align: center; }
.contact { max-width: 760px; margin: 0 auto; }
.contact__title { font-family: var(--font-display); font-weight: 700; font-size: clamp(2rem, 5vw, 3.2rem); letter-spacing: -1px; margin: 14px 0 18px; }
.contact__sub { color: var(--text-dim); font-size: 1.1rem; margin-bottom: 34px; }
.contact__actions { display: flex; gap: 16px; justify-content: center; flex-wrap: wrap; margin-bottom: 28px; }
.contact__links { display: flex; gap: 26px; justify-content: center; flex-wrap: wrap; color: var(--text-dim); font-family: var(--font-mono); font-size: 0.9rem; }
.contact__links a { transition: color 0.2s; }
.contact__links a:hover { color: var(--accent); }

/* ---------- footer ---------- */
.footer {
  border-top: 1px solid var(--border); padding: 30px clamp(18px, 5vw, 48px);
  display: flex; justify-content: space-between; flex-wrap: wrap; gap: 10px;
  color: var(--text-faint); font-size: 0.88rem; max-width: var(--maxw); margin: 0 auto;
}
.footer__built { font-family: var(--font-mono); }

/* ---------- reveal animation ---------- */
.reveal { opacity: 0; transform: translateY(28px); transition: opacity 0.7s var(--ease), transform 0.7s var(--ease); }
.reveal.is-in { opacity: 1; transform: none; }
@keyframes fadeUp { from { opacity: 0; transform: translateY(10px); } to { opacity: 1; transform: none; } }

/* ---------- responsive ---------- */
@media (max-width: 940px) {
  .nav__links { display: none; }
  .nav__burger { display: flex; }
  .hero__inner { grid-template-columns: 1fr; text-align: center; }
  .hero__visual { order: -1; }
  .hero__eyebrow, .hero__cta, .hero__socials { justify-content: center; }
  .hero__lede, .hero__pitch { margin-left: auto; margin-right: auto; }
  .about { grid-template-columns: 1fr; }
  .projects, .skills { grid-template-columns: repeat(2, 1fr); }
  .two-col { grid-template-columns: 1fr; }
  .awards { grid-template-columns: repeat(2, 1fr); }
  .metrics { grid-template-columns: repeat(2, 1fr); }

  /* mobile menu */
  .nav__links.is-open {
    display: flex; flex-direction: column; position: absolute; top: 100%; left: 0; right: 0;
    background: rgba(6,8,20,0.97); backdrop-filter: blur(14px);
    border-bottom: 1px solid var(--border); padding: 16px clamp(18px,5vw,48px); gap: 4px;
  }
}
@media (max-width: 600px) {
  .projects, .skills, .awards, .metrics { grid-template-columns: 1fr; }
  .nav__name { display: none; }
  .nav__resume { display: none; }
  .mode-toggle__btn { padding: 6px 10px; font-size: 0.72rem; }
  .hero__badge--1 { left: -4%; }
  .hero__badge--2 { right: -6%; }
  .footer { flex-direction: column; text-align: center; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { animation: none !important; transition: none !important; }
  .reveal { opacity: 1; transform: none; }
}