/* ============================================================
   Starship, Explained — shared design system
   Every module styles itself under its own section id and
   uses ONLY these tokens for color / type / spacing.
   ============================================================ */
:root {
  /* surfaces */
  --bg: #04060a;
  --bg-2: #080c13;
  --panel: #0c121b;
  --panel-2: #111925;
  --line: #1b2533;
  --line-2: #2a3647;

  /* text */
  --text: #e8edf3;
  --text-2: #b4c0ce;
  --muted: #7b889a;
  --faint: #4b5768;

  /* semantic accents */
  --steel: #c9d3de;      /* stainless hull */
  --steel-dark: #8d99a8;
  --flame: #ff7a1a;      /* engine exhaust / heat */
  --flame-2: #ffc46b;    /* exhaust core */
  --plasma: #ff4f6d;     /* reentry plasma */
  --methane: #45b8ff;    /* CH4 / fuel */
  --lox: #a8f0ff;        /* liquid oxygen */
  --booster: #e7b65a;    /* Super Heavy highlight color */
  --ship: #7fd4c1;       /* Starship (upper stage) highlight color */
  --tower: #9aa7ff;      /* tower / chopsticks */
  --ok: #4ade80;
  --warn: #facc15;
  --bad: #f87171;

  /* type */
  --font-display: "Geist", "Helvetica Neue", Arial, sans-serif;
  --font-body: "Geist", "Helvetica Neue", Arial, sans-serif;
  --font-mono: "Geist Mono", ui-monospace, Menlo, monospace;

  /* spacing scale */
  --s1: 4px; --s2: 8px; --s3: 12px; --s4: 16px; --s5: 24px;
  --s6: 32px; --s7: 48px; --s8: 64px; --s9: 96px;

  --radius: 10px;
  --radius-sm: 6px;
  --maxw: 1240px;
  --ease: cubic-bezier(.2,.7,.2,1);
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}
img, svg, canvas { display: block; max-width: 100%; }
a { color: var(--methane); text-decoration: none; }
a:hover { text-decoration: underline; }
button { font: inherit; color: inherit; }

/* ---------- layout primitives ---------- */
.wrap { max-width: var(--maxw); margin: 0 auto; padding: 0 var(--s4); }
@media (min-width: 720px) { .wrap { padding: 0 var(--s6); } }

.section { padding: var(--s9) 0; border-top: 1px solid var(--line); position: relative; }
.section-head { max-width: 760px; margin-bottom: var(--s7); }
.eyebrow {
  font-family: var(--font-mono); font-size: 12px; letter-spacing: .14em;
  text-transform: uppercase; color: var(--flame); margin: 0 0 var(--s3);
  display: flex; align-items: center; gap: var(--s2);
}
.eyebrow .num { color: var(--muted); }
h1, h2, h3, h4 { font-family: var(--font-display); margin: 0; letter-spacing: -0.01em; line-height: 1.1; }
h2 { font-size: clamp(30px, 4.4vw, 52px); font-weight: 800; }
h3 { font-size: clamp(20px, 2.2vw, 26px); font-weight: 700; }
h4 { font-size: 16px; font-weight: 700; }
.lede { font-size: clamp(16px, 1.5vw, 19px); color: var(--text-2); margin: var(--s4) 0 0; }
p { margin: 0 0 var(--s4); }
.muted { color: var(--muted); }
.mono { font-family: var(--font-mono); }

/* ---------- components ---------- */
.panel {
  background: var(--panel); border: 1px solid var(--line);
  border-radius: var(--radius); padding: var(--s5);
}
.btn {
  appearance: none; border: 1px solid var(--line-2); background: var(--panel-2);
  color: var(--text); padding: 8px 14px; border-radius: var(--radius-sm);
  font-family: var(--font-mono); font-size: 13px; cursor: pointer;
  min-height: 36px; transition: border-color .15s var(--ease), background .15s var(--ease), color .15s;
  display: inline-flex; align-items: center; gap: 6px; white-space: nowrap;
}
.btn:hover { border-color: var(--steel-dark); }
.btn:focus-visible { outline: 2px solid var(--methane); outline-offset: 2px; }
.btn.is-active, .btn[aria-pressed="true"] { background: var(--text); color: var(--bg); border-color: var(--text); }
.btn-primary { background: var(--flame); border-color: var(--flame); color: #1a0a00; font-weight: 600; }
.btn-primary:hover { background: var(--flame-2); border-color: var(--flame-2); }

.chip {
  display: inline-flex; align-items: center; gap: 6px; font-family: var(--font-mono);
  font-size: 11px; letter-spacing: .06em; text-transform: uppercase;
  padding: 3px 8px; border-radius: 999px; border: 1px solid var(--line-2); color: var(--text-2);
}
.dot { width: 8px; height: 8px; border-radius: 50%; display: inline-block; }

.stat { display: flex; flex-direction: column; gap: 2px; }
.stat .k { font-family: var(--font-mono); font-size: 11px; letter-spacing: .1em; text-transform: uppercase; color: var(--muted); }
.stat .v { font-family: var(--font-mono); font-size: 20px; color: var(--text); font-variant-numeric: tabular-nums; }

input[type="range"] { width: 100%; accent-color: var(--flame); }

.steps { display: flex; gap: var(--s2); flex-wrap: wrap; }
.note {
  font-size: 13px; color: var(--muted); border-left: 2px solid var(--line-2);
  padding-left: var(--s3); margin-top: var(--s4);
}
.grid-2 { display: grid; gap: var(--s5); grid-template-columns: 1fr; }
@media (min-width: 900px) { .grid-2 { grid-template-columns: 1fr 1fr; } }

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { animation-duration: .001ms !important; transition-duration: .001ms !important; }
}