:root {
  --bg: rgb(13, 16, 21);
  --panel: rgba(26, 31, 40, 0.8);
  --line: rgba(255, 255, 255, 0.09);
  --text: #e2e6ee;
  --dim: #98a1b2;
  --accent: #7fd1b9;
  --rival: #e56ba2;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 17px/1.6 ui-sans-serif, system-ui, -apple-system, "Segoe UI", sans-serif;
  -webkit-font-smoothing: antialiased;
}

main { max-width: 860px; margin: 0 auto; padding: 0 20px 96px; }

header { padding: 72px 0 40px; }
header h1 { margin: 0 0 12px; font-size: clamp(36px, 7vw, 60px); line-height: 1.05; letter-spacing: -0.02em; }
header p { margin: 0 0 28px; max-width: 34em; color: var(--dim); font-size: 20px; }

.actions { display: flex; flex-wrap: wrap; gap: 12px; }
.button {
  display: inline-block;
  padding: 10px 20px;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.06);
  color: var(--text);
  font: inherit;
  font-size: 15px;
  text-decoration: none;
  cursor: pointer;
}
.button:hover { background: rgba(255, 255, 255, 0.12); }
.button.primary { background: var(--accent); border-color: var(--accent); color: #08110e; font-weight: 600; }
.button.primary:hover { filter: brightness(1.08); }
.button:focus-visible { outline: 2px solid var(--accent); outline-offset: 3px; }

h2 { margin: 72px 0 8px; font-size: 30px; letter-spacing: -0.01em; }
h3 { margin: 28px 0 6px; font-size: 19px; }
.lede { margin: 0 0 28px; color: var(--dim); }
a { color: var(--accent); }
strong { font-weight: 650; }
.you { color: var(--accent); font-weight: 600; }
.rival { color: var(--rival); font-weight: 600; }

/* One rule: a looping board on the left, a sentence or two on the right. */
.rule {
  display: grid;
  grid-template-columns: minmax(0, 5fr) minmax(0, 4fr);
  gap: 28px;
  align-items: center;
  margin: 20px 0;
  padding: 20px;
  border: 1px solid var(--line);
  border-radius: 18px;
  background: var(--panel);
}
.rule canvas { display: block; width: 100%; border-radius: 10px; }
.rule .step { color: var(--dim); font-size: 13px; letter-spacing: 0.1em; text-transform: uppercase; }
.rule h3 { margin: 4px 0 8px; font-size: 22px; line-height: 1.25; }
.rule p { margin: 0; color: var(--dim); }

ul.plain { padding-left: 1.1em; }
ul.plain li { margin: 8px 0; }

details { margin: 14px 0; border: 1px solid var(--line); border-radius: 14px; background: var(--panel); }
summary { padding: 14px 18px; cursor: pointer; font-weight: 600; }
details > div { padding: 0 18px 16px; }

.scroll { overflow-x: auto; }
table { width: 100%; border-collapse: collapse; font-size: 15px; }
th, td { padding: 8px 12px 8px 0; border-bottom: 1px solid var(--line); text-align: left; vertical-align: top; }
th { color: var(--dim); font-weight: 600; font-size: 12px; letter-spacing: 0.08em; text-transform: uppercase; }
code, pre { font: 14px/1.55 ui-monospace, "SF Mono", Menlo, Consolas, monospace; }
code { padding: 1px 5px; border-radius: 5px; background: rgba(255, 255, 255, 0.08); }
td code { white-space: nowrap; }

.prompt { position: relative; margin: 18px 0; border: 1px solid var(--line); border-radius: 14px; background: #090b0f; }
.prompt pre { margin: 0; padding: 18px 18px 22px; white-space: pre-wrap; overflow-wrap: anywhere; color: #cfd6e2; }
.prompt .bar { display: flex; justify-content: space-between; align-items: center; padding: 10px 12px 10px 18px; border-bottom: 1px solid var(--line); color: var(--dim); font-size: 13px; }
.prompt .button { padding: 6px 14px; font-size: 13px; }

footer { margin-top: 72px; padding-top: 24px; border-top: 1px solid var(--line); color: var(--dim); font-size: 14px; }

@media (max-width: 700px) {
  body { font-size: 16px; }
  header { padding-top: 44px; }
  .rule { grid-template-columns: 1fr; gap: 16px; padding: 16px; }
}