:root { color-scheme: light; --ink: #14304a; --sub: #4c6070; --orange: #f28a0f; --orange-dark: #b85f00; --blue: #2a8fd6; --bg: #f6f9fb; --card: #fff; --line: #d5e0e8; }
* { box-sizing: border-box; }
body { margin: 0; background: var(--bg); color: var(--ink); font: 16px/1.9 -apple-system, BlinkMacSystemFont, "Hiragino Sans", "Noto Sans JP", sans-serif; overflow-wrap: anywhere; }
a { color: var(--orange-dark); text-underline-offset: 3px; }
.top { padding: 14px 20px; border-bottom: 1px solid var(--line); background: var(--card); font-weight: 700; }
.top a { color: var(--ink); text-decoration: none; }
main { max-width: 760px; margin: 0 auto; padding: 28px 20px 48px; }
h1 { font-size: clamp(24px, 5vw, 32px); line-height: 1.45; margin: 4px 0 16px; }
h2 { font-size: 22px; line-height: 1.5; margin: 40px 0 12px; padding-left: 12px; border-left: 5px solid var(--orange); }
.date { color: var(--sub); font-size: 14px; margin: 0; }
.lead { font-size: 17px; }
.rules li { margin-bottom: 8px; }
.calc { background: var(--card); border: 1px solid var(--line); border-radius: 10px; padding: 12px 16px; font-variant-numeric: tabular-nums; }
.fig { margin: 20px 0; background: var(--card); border: 1px solid var(--line); border-radius: 14px; padding: 12px; }
.fig svg { display: block; width: 100%; max-width: 420px; height: auto; margin: 0 auto; }
.fig figcaption { text-align: center; color: var(--sub); font-size: 14px; }
.figs { display: grid; grid-template-columns: repeat(auto-fit, minmax(240px, 1fr)); gap: 12px; }
.figs .fig { margin: 0; }
.edge { stroke: var(--ink); stroke-width: 2; }
.edge.hidden { stroke-dasharray: 6 5; stroke-width: 1.5; }
.section { fill: rgba(242, 138, 15, .35); stroke: var(--orange); stroke-width: 2.5; stroke-linejoin: round; }
.helper { stroke: var(--blue); stroke-dasharray: 4 4; stroke-width: 1.5; }
.point { fill: var(--orange); }
.fig text { font: 700 15px -apple-system, BlinkMacSystemFont, sans-serif; fill: var(--ink); text-anchor: middle; }
.fig .point-label { fill: var(--orange-dark); }
.app-box { margin: 48px 0 24px; padding: 20px; border-radius: 16px; background: var(--ink); color: #fff; }
.app-box a { color: #ffc27a; }
.app-title { font-weight: 700; font-size: 18px; margin-top: 0; }
.soon { display: inline-block; margin: 0; padding: 6px 14px; border-radius: 999px; background: rgba(255, 255, 255, .14); font-size: 14px; }
.cta { display: inline-block; padding: 10px 20px; border-radius: 999px; background: var(--orange); color: #fff !important; font-weight: 700; text-decoration: none; }
.more ul, .index { padding-left: 0; list-style: none; }
.more li { margin: 6px 0; }
.index li a { display: block; margin: 12px 0; padding: 16px 18px; border-radius: 14px; background: var(--card); border: 1px solid var(--line); color: var(--ink); text-decoration: none; }
.index li span { display: block; color: var(--sub); font-size: 14px; }
footer { border-top: 1px solid var(--line); padding: 20px; text-align: center; color: var(--sub); font-size: 14px; }
footer nav { display: flex; gap: 8px 20px; justify-content: center; flex-wrap: wrap; }