:root {
  --paper: #f7f7f4; --card: #ffffff; --ink: #0f1722; --muted: #525c69; --line: #dcdcd4;
  --brand: #2a5bd7; --brand-soft: #e7edfb; --series-1: #2a78d6; --series-bench: #8a8984;
  --up: #0f7a3d; --down: #b42318; --focus: #2563eb; --radius: 14px;
  color-scheme: light;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --paper: #0d1117; --card: #151b24; --ink: #edf1f6; --muted: #a3adba; --line: #283241;
    --brand: #8fb0ff; --brand-soft: #1b2540; --series-1: #3987e5; --series-bench: #9a9890;
    --up: #5fd38d; --down: #ff8a80;
    color-scheme: dark;
  }
}
* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body { margin: 0; background: var(--paper); color: var(--ink); font: 17px/1.55 ui-sans-serif, system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif; }
a { color: var(--brand); text-underline-offset: 3px; }
a:focus-visible, button:focus-visible { outline: 3px solid var(--focus); outline-offset: 2px; border-radius: 6px; }
.wrap { max-width: 1040px; margin: 0 auto; padding: 0 16px; }
header.site { border-bottom: 1px solid var(--line); }
header.site .wrap { display: flex; align-items: center; justify-content: space-between; gap: 12px; min-height: 60px; flex-wrap: wrap; }
.brand { display: inline-flex; align-items: center; gap: 10px; font-weight: 800; font-size: 20px; letter-spacing: -0.02em; color: var(--ink); text-decoration: none; }
.brand svg { width: 28px; height: 28px; }
nav.top { display: flex; gap: 16px; font-size: 15px; flex-wrap: wrap; }
nav.top a { color: var(--muted); text-decoration: none; }
nav.top a:hover { color: var(--ink); }
.hero { padding-top: 56px; padding-bottom: 32px; display: grid; grid-template-columns: minmax(0, 1.05fr) minmax(0, 0.95fr); gap: 40px; align-items: center; }
@media (max-width: 820px) { .hero { grid-template-columns: 1fr; padding-top: 32px; gap: 28px; } }
h1 { font-size: clamp(34px, 6vw, 54px); line-height: 1.05; letter-spacing: -0.035em; margin: 0 0 16px; }
h2 { font-size: clamp(24px, 3.4vw, 32px); letter-spacing: -0.02em; margin: 0 0 12px; line-height: 1.15; }
h3 { font-size: 18px; margin: 0 0 6px; }
.lead { font-size: 19px; color: var(--muted); max-width: 36em; }
.accent { color: var(--brand); }
.actions { display: flex; gap: 12px; flex-wrap: wrap; margin-top: 24px; align-items: center; }
.btn { display: inline-flex; align-items: center; justify-content: center; min-height: 48px; padding: 0 22px; border-radius: 999px; background: var(--brand); color: #fff; font-weight: 700; text-decoration: none; border: 0; font-size: 16px; }
@media (prefers-color-scheme: dark) { :root:not([data-theme="light"]) .btn:not(.secondary) { color: #0b1430; } }
.btn.secondary { background: transparent; color: var(--ink); border: 1.5px solid var(--line); }
.pill { display: inline-flex; align-items: center; min-height: 40px; padding: 0 16px; border-radius: 999px; background: var(--brand-soft); color: var(--brand); font-weight: 700; font-size: 15px; }
section { padding: 36px 0; }
section + section { border-top: 1px solid var(--line); }
.steps { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 16px; padding: 0; margin: 20px 0 0; list-style: none; counter-reset: s; }
@media (max-width: 760px) { .steps { grid-template-columns: 1fr; } }
.steps li { background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); padding: 18px; counter-increment: s; }
.steps li::before { content: counter(s); display: inline-grid; place-items: center; width: 30px; height: 30px; border-radius: 8px; background: var(--brand-soft); color: var(--brand); font-weight: 800; margin-bottom: 10px; }
.steps p { margin: 0; color: var(--muted); font-size: 16px; }
.panel { background: var(--card); border: 1px solid var(--line); border-radius: 20px; padding: 16px; }
.panel .meta { display: flex; justify-content: space-between; gap: 8px; font-size: 14px; color: var(--muted); margin: 0 2px 10px; flex-wrap: wrap; }
.panel .meta strong { color: var(--ink); }
.chart { width: 100%; height: auto; display: block; }
.chart .grid { stroke: var(--line); stroke-width: 1; }
.chart .zero { stroke: var(--muted); stroke-width: 1; stroke-dasharray: 3 3; opacity: .6; }
.chart .s1 { fill: none; stroke: var(--series-1); stroke-width: 2; stroke-linejoin: round; stroke-linecap: round; }
.chart .sb { fill: none; stroke: var(--series-bench); stroke-width: 2; stroke-linejoin: round; stroke-linecap: round; stroke-dasharray: 5 4; }
.chart text { fill: var(--muted); font-size: 12px; }
.legend { display: flex; gap: 16px; flex-wrap: wrap; font-size: 14px; color: var(--muted); margin: 8px 2px 0; }
.legend .k { display: inline-block; width: 18px; height: 0; border-top: 2px solid var(--series-1); vertical-align: middle; margin-right: 6px; }
.legend .k.b { border-top: 2px dashed var(--series-bench); }
.tiles { display: grid; grid-template-columns: repeat(auto-fit, minmax(140px, 1fr)); gap: 10px; margin: 14px 0; }
.tile { background: var(--card); border: 1px solid var(--line); border-radius: 12px; padding: 10px 12px; }
.tile .v { font-size: 22px; font-weight: 800; letter-spacing: -0.02em; }
.tile .l { font-size: 13px; color: var(--muted); }
.tile .s { font-size: 13px; color: var(--muted); }
.rules { padding-left: 1.1em; margin: 8px 0; }
.rules li { margin: 4px 0; }
.kinds { display: grid; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); gap: 12px; padding: 0; list-style: none; }
.kinds li { background: var(--card); border: 1px solid var(--line); border-radius: 12px; padding: 14px; }
.kinds li p { margin: 4px 0 0; color: var(--muted); font-size: 15px; }
.narrow { max-width: 680px; }
.faq dt { font-weight: 700; margin-top: 18px; }
.faq dd { margin: 4px 0 0; color: var(--muted); }
.note { font-size: 14px; color: var(--muted); }
.prose { max-width: 760px; }
.prose h1 { font-size: clamp(30px, 5vw, 42px); }
.prose h2 { font-size: 22px; margin-top: 32px; }
.prose table { border-collapse: collapse; width: 100%; font-size: 15px; }
.prose th, .prose td { border: 1px solid var(--line); padding: 8px 10px; text-align: left; vertical-align: top; }
.table-scroll { overflow-x: auto; margin: 12px 0; }
footer.site { border-top: 1px solid var(--line); padding: 28px 0 40px; font-size: 14px; color: var(--muted); }
footer.site .wrap { display: grid; gap: 10px; }
footer.site nav { display: flex; gap: 16px; flex-wrap: wrap; }
footer.site a { color: var(--muted); }
.guide h1 { font-size: clamp(30px, 5vw, 44px); line-height: 1.1; }
.guide h2, .use h2 { margin-top: 32px; }
.crumbs { margin: 0 0 8px; font-size: 14px; }
.answer { color: var(--ink); max-width: none; }
.updated { font-size: 14px; color: var(--muted); }
.howto { padding-left: 1.3em; }
.howto li { margin: 8px 0; }
table.compare { border-collapse: collapse; width: 100%; font-size: 15px; background: var(--card); }
table.compare.wide { min-width: 560px; }
table.compare th, table.compare td { border: 1px solid var(--line); padding: 8px 10px; text-align: left; vertical-align: top; }
table.compare thead th { background: var(--brand-soft); }
.guide-list { padding-left: 1.1em; }
.guide-list li { margin: 14px 0; }
.prompts { display: grid; gap: 10px; padding: 0; list-style: none; }
.prompts li { background: var(--card); border: 1px solid var(--line); border-radius: 12px; padding: 12px 14px; font-weight: 600; }
.up { color: var(--up); } .down { color: var(--down); }