:root {
  --ink: #0a0a0b; --line: #26262b; --line-2: #3a3a41; --text: #ecebe6; --muted: #8a8a90;
  --red: #ff4646; --green: #72e872; color-scheme: dark;
}
* { box-sizing: border-box; }
body { margin: 0; background: var(--ink); color: var(--text); font: 17px/1.6 system-ui, -apple-system, "Segoe UI", Roboto, sans-serif; }
a { color: var(--text); }
.top { display: flex; justify-content: space-between; align-items: center; max-width: 760px; margin: 0 auto; padding: 18px 16px; }
.logo { font-weight: 700; font-size: 20px; text-decoration: none; letter-spacing: -.01em; }
.logo span { color: var(--red); }
.top-cta { color: var(--muted); font-size: 14px; text-decoration: none; border-bottom: 1px solid var(--line-2); padding-bottom: 2px; }
main { max-width: 760px; margin: 0 auto; padding: 0 16px 40px; }
.crumbs { color: var(--muted); font-size: 14px; margin-top: 8px; }
.crumbs a { color: var(--muted); }
h1 { font-size: clamp(27px, 5vw, 38px); line-height: 1.15; margin: 8px 0 14px; letter-spacing: -.015em; }
h2 { font-size: 22px; margin: 36px 0 10px; }
.problem { color: #cfcec9; }
.board-wrap { margin: 18px 0 0; }
.board { display: block; width: 100%; max-width: 560px; margin: 0 auto; aspect-ratio: 1; background: var(--ink); border: 1px solid #1d1d21; border-radius: 12px; }
.board path { fill: none; stroke-linecap: round; stroke-linejoin: round; }
.board .hit { fill: transparent; }
.board .pen-tip { opacity: 0; transition: opacity .35s; stroke: #ffffffcc; stroke-width: 1.5; }
.board .pen-tip.on { opacity: .95; transition: opacity .1s; }
figcaption { display: flex; flex-direction: column; align-items: center; gap: 10px; margin-top: 12px; min-height: 84px; }
.play { background: var(--text); color: var(--ink); border: 0; border-radius: 10px; padding: 10px 18px; font: inherit; font-size: 15px; font-weight: 600; cursor: pointer; }
.cap { text-align: center; color: var(--text); font-size: 17px; max-width: 560px; }
.steps { padding-left: 22px; }
.steps li { margin: 0 0 12px; }
.steps p { margin: 0; }
.steps .wrote { color: var(--muted); font-size: 15px; margin-top: 2px; }
.answer { border-left: 3px solid var(--red); padding: 6px 12px; background: #ffffff08; }
.join { margin-top: 40px; padding: 22px; border: 1px solid var(--line); border-radius: 14px; }
.join h2 { margin-top: 0; }
.join p { color: #cfcec9; }
.form { display: flex; gap: 8px; flex-wrap: wrap; }
.form input { flex: 1 1 220px; min-width: 0; background: #131315; border: 1px solid var(--line-2); border-radius: 10px; padding: 12px 14px; font: inherit; color: var(--text); }
.form button { background: var(--text); color: var(--ink); border: 0; border-radius: 10px; padding: 12px 18px; font: inherit; font-weight: 600; cursor: pointer; }
.form .hp { position: absolute; left: -9999px; width: 1px; height: 1px; opacity: 0; }
.msg { min-height: 1.6em; font-size: 15px; }
.msg.ok { color: var(--green); }
.msg.bad { color: var(--red); }
.index { padding-left: 20px; }
.index li { margin: 6px 0; }
.foot { max-width: 760px; margin: 0 auto; padding: 24px 16px 40px; color: var(--muted); font-size: 14px; border-top: 1px solid var(--line); }
.foot a { color: var(--muted); }