/* Colors borrowed from Gravity Wars: planets are red (light), green (medium), blue (dense). */
:root {
  --space: #0b1026;
  --space-raised: #151c3f;
  --ink: #ece8dc;
  --muted: #a9b0cf;
  --red: #ff6b5e;
  --green: #6ee7a8;
  --blue: #6cb4ff;
  --gold: #ffd166;
  --mono: ui-monospace, "SF Mono", Menlo, Consolas, monospace;
  --sans: system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
}

*, *::before, *::after { box-sizing: border-box; }

html { font-size: 112.5%; }

body {
  margin: 0;
  color: var(--ink);
  font-family: var(--sans);
  line-height: 1.65;
  background-color: var(--space);
  /* A tiled starfield. */
  background-image:
    radial-gradient(circle at 23px 37px, #fff 0 1px, transparent 1.6px),
    radial-gradient(circle at 141px 88px, #cfd8ff 0 1px, transparent 1.6px),
    radial-gradient(circle at 211px 163px, #fff 0 1.4px, transparent 2px),
    radial-gradient(circle at 67px 221px, #ffe9b0 0 1px, transparent 1.6px),
    radial-gradient(circle at 272px 41px, #fff 0 0.8px, transparent 1.4px),
    radial-gradient(circle at 178px 262px, #b9f5d6 0 0.8px, transparent 1.4px),
    radial-gradient(circle at 98px 140px, #fff 0 0.6px, transparent 1.2px);
  background-size: 300px 290px;
  background-attachment: fixed;
}

a { color: var(--gold); text-underline-offset: 0.18em; }
a:hover { color: #fff; }
a:focus-visible { outline: 2px dashed var(--gold); outline-offset: 3px; }

.skip-link {
  position: absolute;
  left: -999px;
  top: 0.5rem;
  background: var(--gold);
  color: var(--space);
  padding: 0.4rem 0.8rem;
  border-radius: 0.3rem;
}
.skip-link:focus { left: 0.5rem; }

/* Header */
.site-header {
  max-width: 46rem;
  margin: 0 auto;
  padding: 2rem 1.25rem 1rem;
  display: flex;
  flex-wrap: wrap;
  gap: 1rem 2rem;
  align-items: center;
  justify-content: space-between;
}

.brand {
  display: flex;
  align-items: center;
  gap: 0.8rem;
  color: var(--ink);
  text-decoration: none;
}
.brand:hover { color: var(--ink); }
.brand-text { display: flex; flex-direction: column; }
.brand-name { font-family: var(--mono); font-size: 1.15rem; font-weight: 700; letter-spacing: 0.02em; }
.brand-tagline { color: var(--muted); font-size: 0.8rem; }

.orbit { width: 3.2rem; height: 3.2rem; flex: none; overflow: visible; }
.orbit-path { fill: none; stroke: var(--muted); stroke-width: 0.6; stroke-dasharray: 2 3; opacity: 0.6; }
.planet { fill: var(--blue); }
.torpedo { fill: var(--gold); transform-box: view-box; transform-origin: 24px 24px; animation: orbit 7s linear infinite; }
@keyframes orbit { to { transform: rotate(360deg); } }

.site-nav { display: flex; flex-wrap: wrap; gap: 0.4rem 1.1rem; font-family: var(--mono); font-size: 0.85rem; }
.site-nav a { color: var(--muted); text-decoration: none; padding: 0.15rem 0; border-bottom: 2px solid transparent; }
.site-nav a:hover { color: var(--ink); }
.site-nav a[aria-current="page"] { color: var(--ink); border-bottom-color: var(--gold); }

/* Main content */
.content {
  max-width: 46rem;
  margin: 1rem auto 2rem;
  padding: 1.5rem 1.25rem 2rem;
  background: rgba(11, 16, 38, 0.82);
  border-radius: 1rem;
}
@media (min-width: 48rem) {
  .content { padding: 2rem 2.5rem 2.5rem; border: 1px solid rgba(169, 176, 207, 0.15); }
}

h1, h2, h3 { font-family: var(--mono); line-height: 1.25; }
h1 { font-size: 2rem; margin: 0 0 1rem; }
h2 { font-size: 1.3rem; margin: 2.4rem 0 0.8rem; }
h3 { font-size: 1.05rem; margin: 1.8rem 0 0.4rem; color: var(--gold); }

/* Each section heading gets a little planet, cycling through the three planet colors. */
h2::before {
  content: "";
  display: inline-block;
  width: 0.7em;
  height: 0.7em;
  margin-right: 0.55em;
  border-radius: 50%;
  background: var(--red);
  box-shadow: 0 0 0.6em rgba(255, 255, 255, 0.25);
  vertical-align: 0.02em;
}
h2:nth-of-type(3n+2)::before { background: var(--green); }
h2:nth-of-type(3n)::before { background: var(--blue); }

ul { padding-left: 1.3rem; }
li { margin: 0.3rem 0; }
li::marker { color: var(--muted); }

code, pre { font-family: var(--mono); font-size: 0.88em; }
code { background: var(--space-raised); padding: 0.1em 0.35em; border-radius: 0.25rem; }
pre { background: var(--space-raised); padding: 0.9rem 1rem; border-radius: 0.5rem; overflow-x: auto; }
pre code { background: none; padding: 0; }

blockquote { margin: 1.2rem 0; padding: 0.2rem 1rem; border-left: 3px solid var(--gold); color: var(--muted); }

hr { border: 0; border-top: 1px dashed rgba(169, 176, 207, 0.35); margin: 2.4rem 0; }

/* Gravity Wars game */
.gw-field {
  position: relative;
  width: 100%;
  max-width: 640px;
  aspect-ratio: 4 / 3;
  margin: 1.5rem auto 0;
  background: #000;
  border: 1px solid rgba(169, 176, 207, 0.35);
}
.gw-field canvas { position: absolute; inset: 0; width: 100%; height: 100%; }
.gw-gameover {
  position: absolute;
  inset: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  background: rgba(0, 0, 0, 0.55);
  font-family: var(--mono);
  font-size: 1.2rem;
}
.gw-gameover[hidden] { display: none; }
.gw-gameover p { margin: 0 0 0.8rem; }

.gw-controls {
  max-width: 640px;
  margin: 0.9rem auto 0;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.6rem 1.2rem;
  font-family: var(--mono);
  font-size: 0.85rem;
}
.gw-player { margin: 0; flex-basis: 100%; }
.gw-controls input {
  width: 5.5em;
  margin-left: 0.3rem;
  padding: 0.3rem 0.4rem;
  font: inherit;
  color: var(--ink);
  background: var(--space-raised);
  border: 1px solid var(--muted);
  border-radius: 0.3rem;
}
.gw-buttons { display: flex; flex-wrap: wrap; gap: 0.5rem; }
.gw-controls button, .gw-gameover button {
  padding: 0.35rem 0.9rem;
  font: inherit;
  color: var(--ink);
  background: var(--space-raised);
  border: 1px solid var(--muted);
  border-radius: 0.3rem;
  cursor: pointer;
}
.gw-controls button:hover:not(:disabled), .gw-gameover button:hover { border-color: var(--gold); }
.gw-controls button:disabled { opacity: 0.45; cursor: default; }
#gw-fire { color: var(--space); background: var(--gold); border-color: var(--gold); font-weight: 700; }
.gw-status { max-width: 640px; min-height: 1.6em; margin: 0.6rem auto 0; color: var(--muted); font-size: 0.85rem; }
.gw-status.error { color: var(--red); }

/* Footer */
.site-footer {
  max-width: 46rem;
  margin: 0 auto;
  padding: 0 1.25rem 2.5rem;
  color: var(--muted);
  font-size: 0.8rem;
  text-align: center;
}
.site-footer a { color: var(--muted); }
.site-footer .updated { margin-top: -0.6rem; font-size: 0.75rem; opacity: 0.8; }

@media (prefers-reduced-motion: reduce) {
  .torpedo { animation: none; }
}