/* Arc3 Play — blueprint/drafting aesthetic */
:root {
  --navy: #0D1B2A;
  --charcoal: #2B2F33;
  --warm-gray: #A7A29A;
  --copper: #BB7333;
  --light: #F5F3F0;
  --grid: rgba(245, 243, 240, 0.05);
  --grid-major: rgba(245, 243, 240, 0.09);
  --sans: -apple-system, BlinkMacSystemFont, "SF Pro Text", "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  --mono: ui-monospace, "SF Mono", Menlo, Consolas, monospace;
}

* { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  min-height: 100vh;
  color: var(--light);
  background-color: var(--navy);
  background-image:
    linear-gradient(var(--grid-major) 1px, transparent 1px),
    linear-gradient(90deg, var(--grid-major) 1px, transparent 1px),
    linear-gradient(var(--grid) 1px, transparent 1px),
    linear-gradient(90deg, var(--grid) 1px, transparent 1px);
  background-size: 120px 120px, 120px 120px, 24px 24px, 24px 24px;
  font-family: var(--sans);
  font-size: 17px;
  line-height: 1.6;
  display: flex;
  flex-direction: column;
}

a { color: var(--copper); text-underline-offset: 3px; }
a:hover { color: #d4894a; }

.wrap { width: 100%; max-width: 760px; margin: 0 auto; padding: 0 16px; }

header.site {
  border-bottom: 1px solid var(--grid-major);
  padding: 18px 0;
}
header.site .wrap { display: flex; align-items: center; justify-content: space-between; gap: 16px; }

.brand {
  display: inline-flex; align-items: center; gap: 10px;
  color: var(--light); text-decoration: none;
  font-weight: 600; letter-spacing: 0.02em;
}
.brand svg { width: 28px; height: 28px; flex: none; }
.brand .play { color: var(--copper); }

nav.site a {
  color: var(--warm-gray); text-decoration: none; font-size: 15px; margin-left: 18px;
}
nav.site a:hover { color: var(--light); }

main { flex: 1; padding: 56px 0 64px; }

.label {
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--copper);
  margin: 0 0 12px;
}

h1 { font-size: clamp(32px, 6vw, 48px); line-height: 1.15; margin: 0 0 16px; font-weight: 650; }
h2 { font-size: 22px; margin: 40px 0 10px; font-weight: 600; }
h3 { font-size: 18px; margin: 28px 0 6px; font-weight: 600; }

p, li { color: rgba(245, 243, 240, 0.86); }
.lede { font-size: 19px; color: var(--light); max-width: 34em; }
.muted { color: var(--warm-gray); font-size: 15px; }

.panel {
  border: 1px solid var(--grid-major);
  background: rgba(13, 27, 42, 0.72);
  padding: 24px;
  margin: 28px 0;
  position: relative;
}
/* registration marks */
.panel::before, .panel::after {
  content: ""; position: absolute; width: 12px; height: 12px;
  border-color: var(--copper); border-style: solid;
}
.panel::before { top: -1px; left: -1px; border-width: 2px 0 0 2px; }
.panel::after { bottom: -1px; right: -1px; border-width: 0 2px 2px 0; }

.button {
  display: inline-block;
  background: var(--copper);
  color: var(--navy);
  font-weight: 600;
  text-decoration: none;
  padding: 12px 22px;
  border-radius: 6px;
  margin: 6px 10px 6px 0;
}
.button:hover { background: #d4894a; color: var(--navy); }
.button.secondary { background: transparent; color: var(--light); border: 1px solid var(--warm-gray); }
.button.secondary:hover { border-color: var(--light); }

.code {
  font-family: var(--mono);
  font-size: 32px;
  letter-spacing: 0.2em;
  color: var(--light);
}

.cards { display: grid; grid-template-columns: repeat(auto-fit, minmax(200px, 1fr)); gap: 16px; margin: 28px 0; }
.cards .panel { margin: 0; }
.cards h3 { margin-top: 0; }

ul { padding-left: 22px; }

footer.site {
  border-top: 1px solid var(--grid-major);
  padding: 24px 0;
  font-size: 14px;
  color: var(--warm-gray);
}
footer.site a { color: var(--warm-gray); margin-right: 16px; }
footer.site a:hover { color: var(--light); }