:root {
  --background: 210 20% 4%;
  --foreground: 193 50% 65%;
  --card: 210 20% 7%;
  --card-foreground: 193 50% 65%;
  --primary: 193 66% 36%;
  --muted-foreground: 210 10% 50%;
  --accent: 200 70% 55%;
  --border: 193 30% 15%;
  --terminal-bg: 210 25% 6%;
  --terminal-border: 193 40% 20%;
  --gold: 45 100% 55%;
  --radius: .5rem;
}

* { box-sizing: border-box; }
html { font-size: 14px; scroll-behavior: smooth; }

body {
  margin: 0;
  min-height: 100vh;
  background-color: hsl(var(--background));
  font-family: "Space Grotesk", sans-serif;
  color: hsl(var(--foreground));
  line-height: 1.5;
  overflow-x: hidden;
}

body:before {
  content: "";
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: 0;
  background:
    radial-gradient(ellipse at top, hsl(var(--primary) / .12) 0%, transparent 58%),
    radial-gradient(ellipse at bottom right, hsl(var(--accent) / .075) 0%, transparent 52%),
    radial-gradient(ellipse at bottom left, hsl(var(--gold) / .035) 0%, transparent 48%);
}

body:after {
  content: "";
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: 1;
  background-image:
    linear-gradient(hsl(var(--primary) / .035) 1px, transparent 1px),
    linear-gradient(90deg, hsl(var(--primary) / .035) 1px, transparent 1px);
  background-size: 42px 42px;
  mask-image: linear-gradient(to bottom, black 0%, transparent 92%);
}

a { color: inherit; text-decoration: none; }

.scanlines {
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: 2;
  opacity: .20;
  background: linear-gradient(rgba(18,16,16,0) 50%, rgba(0,0,0,.28) 50%);
  background-size: 100% 4px;
}

.glow-orb {
  position: fixed;
  width: 420px;
  height: 420px;
  border-radius: 999px;
  pointer-events: none;
  z-index: 0;
  filter: blur(28px);
  opacity: .22;
}

.glow-orb.one {
  top: -160px;
  left: -130px;
  background: hsl(var(--primary) / .55);
}

.glow-orb.two {
  right: -140px;
  bottom: 10%;
  background: hsl(var(--accent) / .42);
}

.site-shell { position: relative; z-index: 3; }

.site-nav {
  position: sticky;
  top: 0;
  z-index: 50;
  background: hsl(var(--background) / .90);
  border-bottom: 1px solid hsl(var(--border) / .65);
  backdrop-filter: blur(18px);
}

.nav-inner {
  width: min(1200px, calc(100% - 38px));
  min-height: 74px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1.5rem;
}

.brand {
  display: flex;
  align-items: center;
  gap: .85rem;
}

.brand-mark {
  width: 54px;
  height: 54px;
  display: grid;
  place-items: center;
  border-radius: .85rem;
  color: hsl(var(--foreground));
  font-weight: 900;
  font-size: 1.5rem;
  background: hsl(var(--primary) / .14);
  border: 1px solid hsl(var(--primary) / .35);
  box-shadow: 0 0 24px hsl(var(--accent) / .18);
}

.brand-name {
  color: hsl(var(--foreground));
  font-size: 1.45rem;
  font-weight: 900;
  letter-spacing: -.055em;
}

.brand-subtitle {
  margin-top: .35rem;
  color: hsl(var(--muted-foreground));
  font-family: "JetBrains Mono", monospace;
  font-size: .72rem;
  letter-spacing: .12em;
  text-transform: uppercase;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: .55rem;
  color: hsl(var(--muted-foreground));
  font-family: "JetBrains Mono", monospace;
  font-size: .78rem;
}

.nav-links a {
  padding: .58rem .82rem;
  border: 1px solid transparent;
  border-radius: var(--radius);
  transition: .16s ease;
}

.nav-links a:hover {
  color: hsl(var(--foreground));
  background: hsl(var(--card) / .8);
  border-color: hsl(var(--primary) / .35);
  box-shadow: 0 0 24px hsl(var(--primary) / .13);
}

.container {
  width: min(1200px, calc(100% - 38px));
  margin: 0 auto;
  padding: 2.1rem 0 5rem;
}

.hero {
  position: relative;
  overflow: hidden;
  min-height: 360px;
  display: grid;
  align-items: center;
  margin-bottom: 2.2rem;
  padding: clamp(1.5rem, 4vw, 3rem);
  border: 1px solid hsl(var(--primary) / .2);
  border-radius: .9rem;
  background:
    linear-gradient(135deg, hsl(var(--terminal-bg) / .96), hsl(var(--card) / .88)),
    radial-gradient(ellipse at top right, hsl(var(--primary) / .16), transparent 36rem);
  box-shadow: 0 28px 80px rgb(0 0 0 / .48), inset 0 1px 0 hsl(var(--foreground) / .06);
}

.hero.compact { min-height: 230px; }

.hero-grid {
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(hsl(var(--primary) / .06) 1px, transparent 1px),
    linear-gradient(90deg, hsl(var(--primary) / .06) 1px, transparent 1px);
  background-size: 34px 34px;
  mask-image: radial-gradient(circle at center, black 0%, transparent 76%);
}

.hero-content {
  position: relative;
  z-index: 2;
  max-width: 860px;
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: .55rem;
  margin-bottom: .9rem;
  padding: .45rem .72rem;
  color: hsl(var(--accent));
  background: hsl(var(--primary) / .08);
  border: 1px solid hsl(var(--primary) / .3);
  border-radius: 999px;
  font-family: "JetBrains Mono", monospace;
  font-size: .72rem;
  font-weight: 800;
  letter-spacing: .1em;
  text-transform: uppercase;
}

.pulse-dot {
  width: .46rem;
  height: .46rem;
  border-radius: 999px;
  background: hsl(var(--accent));
  box-shadow: 0 0 14px hsl(var(--accent));
}

.hero h1 {
  margin: 0;
  color: hsl(var(--foreground));
  font-size: clamp(3rem, 8vw, 6.5rem);
  line-height: .88;
  font-weight: 900;
  letter-spacing: -.085em;
}

.hero.compact h1 {
  font-size: clamp(2.3rem, 5vw, 4.8rem);
}

.hero h1 span {
  color: hsl(var(--accent));
  text-shadow: 0 0 34px hsl(var(--accent) / .24);
}

.hero p {
  max-width: 760px;
  margin: 1rem 0 0;
  color: hsl(var(--muted-foreground));
  font-size: 1.04rem;
}

.terminal-line {
  width: fit-content;
  max-width: 100%;
  margin-top: 1.45rem;
  padding: .82rem .95rem;
  color: hsl(var(--foreground));
  background: hsl(var(--background) / .78);
  border: 1px solid hsl(var(--terminal-border));
  border-radius: .65rem;
  font-family: "JetBrains Mono", monospace;
  font-size: .82rem;
  overflow-wrap: anywhere;
}

.prompt {
  color: hsl(var(--gold));
  margin-right: .5rem;
}

.topbar { margin-bottom: 1.2rem; }

.topbar a {
  display: inline-flex;
  align-items: center;
  padding: .62rem .85rem;
  color: hsl(var(--accent));
  background: hsl(var(--card) / .72);
  border: 1px solid hsl(var(--primary) / .28);
  border-radius: .55rem;
  font-family: "JetBrains Mono", monospace;
  font-size: .82rem;
  font-weight: 700;
}

.section-head {
  display: flex;
  align-items: end;
  justify-content: space-between;
  gap: 1rem;
  margin: .45rem 0 1.2rem;
}

.section-head h2 {
  margin: 0;
  color: hsl(var(--foreground));
  font-size: 1.8rem;
  font-weight: 900;
  letter-spacing: -.045em;
}

.terminal-chip {
  padding: .55rem .7rem;
  color: hsl(var(--accent));
  background: hsl(var(--terminal-bg) / .82);
  border: 1px solid hsl(var(--terminal-border));
  border-radius: .55rem;
  font-family: "JetBrains Mono", monospace;
  font-size: .78rem;
}

.grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(285px, 1fr));
  gap: 1rem;
}

.card {
  position: relative;
  overflow: hidden;
  display: block;
  padding: 1.45rem;
  color: hsl(var(--card-foreground));
  background: linear-gradient(180deg, hsl(var(--card) / .94), hsl(var(--terminal-bg) / .84));
  border: 1px solid hsl(var(--primary) / .16);
  border-radius: .8rem;
  box-shadow: 0 16px 48px rgb(0 0 0 / .25);
  transition: transform .18s ease, border-color .18s ease, box-shadow .18s ease;
}

.card:before {
  content: "";
  position: absolute;
  inset: 0;
  opacity: 0;
  background:
    radial-gradient(circle at top right, hsl(var(--accent) / .14), transparent 14rem),
    radial-gradient(circle at bottom left, hsl(var(--gold) / .08), transparent 12rem);
  transition: opacity .18s ease;
}

.card:hover {
  transform: translateY(-4px);
  border-color: hsl(var(--primary) / .42);
  box-shadow: 0 22px 70px rgb(0 0 0 / .36), 0 0 34px hsl(var(--primary) / .13);
}

.card:hover:before { opacity: 1; }

.card > * {
  position: relative;
  z-index: 1;
}

.card-kicker {
  margin-bottom: .55rem;
  color: hsl(var(--accent));
  font-family: "JetBrains Mono", monospace;
  font-size: .72rem;
  font-weight: 800;
  letter-spacing: .1em;
  text-transform: uppercase;
}

.card-title {
  margin-bottom: .55rem;
  color: hsl(var(--foreground));
  font-size: 1.22rem;
  font-weight: 900;
  line-height: 1.22;
  letter-spacing: -.035em;
}

.card-meta {
  color: hsl(var(--muted-foreground));
  font-family: "JetBrains Mono", monospace;
  font-size: .82rem;
}

.challenge-card { min-height: 170px; }

.writeup-page {
  display: grid;
  gap: 1.15rem;
}

.writeup-card {
  padding: 1.55rem;
  color: hsl(var(--card-foreground));
  background: linear-gradient(180deg, hsl(var(--card) / .94), hsl(var(--terminal-bg) / .84));
  border: 1px solid hsl(var(--primary) / .2);
  border-radius: .8rem;
  box-shadow: 0 16px 48px rgb(0 0 0 / .25);
}

.overview-grid {
  display: grid;
  gap: .55rem;
  padding: 1rem;
  color: hsl(var(--foreground));
  background: hsl(var(--background) / .88);
  border: 1px solid hsl(var(--terminal-border));
  border-radius: .75rem;
  font-family: "JetBrains Mono", monospace;
  font-size: .86rem;
}

.overview-grid span {
  color: hsl(var(--accent));
  font-weight: 900;
}

.prose {
  color: hsl(var(--foreground));
}

.prose h1,
.prose h2,
.prose h3 {
  color: hsl(var(--accent));
  letter-spacing: -.035em;
}

.prose h1 { font-size: 2.2rem; }
.prose h2 {
  margin-top: 2rem;
  padding-top: 1rem;
  border-top: 1px solid hsl(var(--primary) / .20);
}

.prose p,
.prose li {
  color: hsl(var(--card-foreground));
}

.prose code {
  color: hsl(var(--gold));
  background: hsl(var(--background) / .88);
  border: 1px solid hsl(var(--terminal-border));
  border-radius: .35rem;
  padding: .08rem .3rem;
  font-family: "JetBrains Mono", monospace;
}

pre {
  white-space: pre-wrap;
  word-break: break-word;
  margin: 1rem 0;
  padding: 1rem;
  color: hsl(var(--foreground));
  background: hsl(var(--background) / .88);
  border: 1px solid hsl(var(--terminal-border));
  border-radius: .75rem;
  overflow-x: auto;
  font-family: "JetBrains Mono", monospace;
  font-size: .85rem;
}

@media (max-width: 720px) {
  .nav-inner {
    min-height: auto;
    padding: 1rem 0;
    align-items: flex-start;
    flex-direction: column;
  }

  .nav-links { flex-wrap: wrap; }
  .hero { min-height: auto; padding: 1.7rem; }
  .section-head { align-items: flex-start; flex-direction: column; }
  .grid { grid-template-columns: 1fr; }
}