:root {
  --paper: #f3f5f8;
  --surface: #fff;
  --ink: #172033;
  --ink-soft: #445168;
  --muted: #7b879a;
  --line: #dce2ea;
  --line-strong: #cbd4e0;
  --blue: #376bea;
  --blue-dark: #2856c2;
  --blue-soft: #edf3ff;
  --green: #159363;
  --font: Inter, "SF Pro Text", "PingFang SC", "Microsoft YaHei", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  --mono: "SFMono-Regular", Menlo, Consolas, monospace;
}

*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: 90px; }
body { margin: 0; min-width: 320px; background: var(--paper); color: var(--ink); font-family: var(--font); font-size: 15px; line-height: 1.7; -webkit-font-smoothing: antialiased; }
a { color: inherit; }

.site-header { position: sticky; top: 0; z-index: 50; display: grid; grid-template-columns: 1fr auto 1fr; align-items: center; min-height: 68px; border-bottom: 1px solid #e2e5eb; background: rgba(255, 255, 255, .96); padding: 0 max(28px, calc((100vw - 1400px) / 2)); backdrop-filter: blur(18px); }
.brand { display: inline-flex; align-items: center; gap: 10px; justify-self: start; text-decoration: none; }
.brand-mark { display: inline-flex; align-items: flex-end; justify-content: center; gap: 3px; width: 32px; height: 32px; border-radius: 7px; background: var(--blue); padding: 7px; }
.brand-mark i { display: block; width: 3px; border-radius: 2px 2px 0 0; background: #fff; }
.brand-mark i:nth-child(1) { height: 8px; }
.brand-mark i:nth-child(2) { height: 17px; }
.brand-mark i:nth-child(3) { height: 12px; }
.brand strong { font-size: 16px; }
.brand-category { border-left: 1px solid #dfe3ea; margin-left: 4px; padding-left: 14px; color: #7c8595; font-size: 11px; }
.site-header > nav { display: flex; align-items: center; gap: 28px; }
.site-header > nav a, .header-link { color: #596477; font-size: 12px; font-weight: 650; text-decoration: none; }
.site-header > nav a:hover, .header-link:hover, .site-header > nav a[aria-current="page"] { color: var(--blue); }
.header-actions { display: flex; align-items: center; justify-self: end; gap: 18px; }
.header-actions .header-link + .header-link { border-left: 1px solid #dfe3ea; padding-left: 18px; }

main { width: min(calc(100% - 64px), 1240px); margin: 0 auto; }
.case-hero { max-width: 820px; padding: 84px 0 60px; }
.eyebrow, .case-number { color: var(--blue); font-family: var(--mono); font-size: 11px; font-weight: 800; letter-spacing: .05em; }
.case-hero h1 { margin: 13px 0 0; font-size: 52px; line-height: 1.17; letter-spacing: 0; }
.case-hero p { max-width: 740px; margin: 19px 0 0; color: var(--ink-soft); font-size: 17px; line-height: 1.8; }
.case-index { display: grid; grid-template-columns: repeat(3, 1fr); border: 1px solid var(--line); border-radius: 8px; background: var(--surface); overflow: hidden; }
.case-index a { display: grid; gap: 3px; min-width: 0; padding: 18px; text-decoration: none; }
.case-index a + a { border-left: 1px solid var(--line); }
.case-index a > span { color: var(--blue); font-family: var(--mono); font-size: 10px; font-weight: 800; }
.case-index strong { margin-top: 5px; font-size: 13px; }
.case-index small { color: var(--muted); font-size: 10px; }
.case-index a:hover { background: var(--blue-soft); }

.case-unit { border-top: 1px solid var(--line-strong); margin-top: 72px; padding-top: 56px; }
.case-heading { display: flex; align-items: flex-end; justify-content: space-between; gap: 50px; padding-bottom: 28px; }
.case-heading h2 { margin: 8px 0 0; font-size: 34px; line-height: 1.3; }
.case-result { display: grid; min-width: 190px; border-left: 1px solid var(--line-strong); padding-left: 25px; }
.case-result > span, .case-result > div > span { color: var(--muted); font-size: 10px; }
.case-result > strong, .case-result > div > strong { margin-top: 4px; color: var(--blue); font-size: 31px; line-height: 1.15; }
.case-result--text { max-width: 250px; }
.case-result--text > strong { font-size: 19px; line-height: 1.35; }
.case-result--double { display: grid; grid-template-columns: repeat(2, 1fr); min-width: 340px; }
.case-result--double > div { display: grid; }
.case-result--double > div + div { border-left: 1px solid var(--line); margin-left: 22px; padding-left: 22px; }
.case-result sup { font-size: .55em; }

.case-chain { display: grid; grid-template-columns: 1fr auto 1fr auto 1fr auto 1fr; align-items: stretch; border: 1px solid var(--line); border-radius: 8px; background: var(--surface); overflow: hidden; }
.case-chain > div { min-width: 0; padding: 20px; }
.case-chain > div > span { color: var(--blue); font-size: 10px; font-weight: 800; }
.case-chain strong { display: block; margin-top: 6px; font-size: 14px; line-height: 1.45; }
.case-chain p { margin: 6px 0 0; color: var(--muted); font-size: 11px; line-height: 1.65; }
.case-chain > i { display: grid; place-items: center; width: 34px; border-right: 1px solid var(--line); border-left: 1px solid var(--line); background: var(--paper); color: #9aa7ba; font-style: normal; }

.case-chart { overflow: hidden; border: 1px solid var(--line-strong); border-radius: 8px; background: var(--surface); margin-top: 18px; box-shadow: 0 12px 28px rgba(38, 52, 78, .05); }
.case-chart > header, .case-chart > footer { display: flex; align-items: center; justify-content: space-between; gap: 25px; padding: 15px 18px; }
.case-chart > header { border-bottom: 1px solid var(--line); }
.case-chart > footer { border-top: 1px solid var(--line); background: var(--blue-soft); color: var(--ink-soft); font-size: 11px; }
.case-chart > header > div { display: grid; }
.case-chart > header strong { font-size: 14px; }
.case-chart > header span { color: var(--muted); font-size: 10px; }
.chart-legend { display: flex !important; align-items: center; gap: 15px; }
.chart-legend > span { display: inline-flex; align-items: center; gap: 6px; }
.chart-legend i { width: 10px; height: 10px; border-radius: 2px; }
.legend-before { background: #b6c0cf; }
.legend-after { background: var(--blue); }
.legend-core { background: #486fe0; }
.legend-new { background: #15947a; }
.legend-other { background: #a8b3c3; }

.funnel-rows { display: grid; gap: 15px; padding: 24px 20px; }
.funnel-row { display: grid; grid-template-columns: 100px minmax(0, 1fr); align-items: center; gap: 18px; }
.funnel-row > strong { font-size: 11px; }
.funnel-bars { display: grid; gap: 5px; }
.funnel-bars > span { display: flex; align-items: center; justify-content: flex-end; width: calc(var(--value) * 1%); min-width: 58px; height: 19px; border-radius: 3px; padding-right: 7px; }
.funnel-bars b { color: #fff; font-size: 9px; }
.bar-before { background: #b6c0cf; }
.bar-after { background: var(--blue); }
.funnel-row.is-focus { border-left: 2px solid var(--blue); padding-left: 10px; }

.revenue-plot { position: relative; height: 310px; padding: 25px 22px 0 70px; }
.plot-grid { position: absolute; inset: 22px 20px 37px 18px; display: flex; justify-content: space-between; flex-direction: column; color: var(--muted); font-size: 9px; }
.plot-grid span { position: relative; }
.plot-grid span::after { position: absolute; top: 50%; left: 42px; width: calc(100% - 42px); border-top: 1px dashed #e4e8ef; content: ""; }
.revenue-bars { position: relative; z-index: 1; display: grid; grid-template-columns: repeat(8, 1fr); align-items: end; gap: 22px; height: 100%; }
.revenue-day { position: relative; display: grid; grid-template-rows: 1fr 30px; align-items: end; height: 100%; }
.revenue-day > span { align-self: center; color: var(--muted); font-size: 9px; text-align: center; }
.revenue-day > b { position: absolute; top: -17px; left: 50%; color: var(--green); font-size: 9px; white-space: nowrap; transform: translateX(-50%); }
.stack { display: flex; justify-content: flex-end; flex-direction: column; width: min(48px, 76%); height: calc(var(--total) * 1%); min-height: 30px; margin: 0 auto; overflow: hidden; border-radius: 3px 3px 0 0; }
.stack i { display: block; flex: 0 0 calc(var(--part) * 1%); }
.seg-core { background: #486fe0; }
.seg-new { background: #15947a; }
.seg-other { background: #a8b3c3; }
.revenue-day.is-launch::before { position: absolute; top: 0; bottom: 30px; left: 50%; border-left: 1px dashed #47a98e; content: ""; z-index: -1; }

.decision-badge { border-radius: 4px; background: #eaf8f2; padding: 5px 9px; color: var(--green) !important; font-size: 10px !important; font-weight: 800; }
.strategy-compare { display: grid; grid-template-columns: repeat(2, 1fr); gap: 32px; padding: 26px 22px; }
.strategy-metric { min-width: 0; }
.strategy-metric > div:first-child { display: flex; align-items: baseline; justify-content: space-between; }
.strategy-metric > div:first-child strong { font-size: 12px; }
.strategy-metric > div:first-child span { color: var(--muted); font-size: 9px; }
.compare-bars { display: grid; gap: 10px; margin-top: 17px; }
.compare-bars > span { display: flex; align-items: center; justify-content: space-between; width: calc(var(--value) * 1%); min-width: 180px; height: 35px; border-radius: 4px; padding: 0 11px; }
.compare-bars i { font-size: 10px; font-style: normal; }
.compare-bars b { font-size: 11px; }
.compare-base { background: #e5e9ef; color: var(--ink-soft); }
.compare-test { background: var(--blue); color: #fff; }
.strategy-chart > footer strong { color: var(--blue); }

.case-cta { display: flex; align-items: center; justify-content: space-between; border-top: 1px solid var(--line-strong); margin-top: 82px; padding: 55px 0; }
.case-cta span { color: var(--muted); font-size: 11px; }
.case-cta h2 { margin: 5px 0 0; font-size: 28px; }
.case-cta > a { display: inline-flex; align-items: center; gap: 28px; min-height: 45px; border-radius: 6px; background: var(--blue); padding: 9px 17px; color: #fff; font-size: 12px; font-weight: 750; text-decoration: none; }
.case-cta > a:hover { background: var(--blue-dark); }
.site-footer { display: grid; grid-template-columns: 1fr auto 1fr; align-items: center; min-height: 74px; border-top: 1px solid var(--line); background: var(--surface); padding: 0 max(28px, calc((100vw - 1240px) / 2)); color: var(--muted); font-size: 10px; }
.site-footer strong { color: var(--ink); }
.site-footer nav { display: flex; justify-content: flex-end; gap: 20px; }
.site-footer a { text-decoration: none; }

@media (max-width: 1050px) {
  .site-header > nav { gap: 16px; }
  .case-index { grid-template-columns: repeat(3, 1fr); }
  .case-chain { grid-template-columns: repeat(2, 1fr); }
  .case-chain > i { display: none; }
  .case-chain > div:nth-of-type(even) { border-left: 1px solid var(--line); }
  .case-chain > div:nth-of-type(n+3) { border-top: 1px solid var(--line); }
}

@media (max-width: 760px) {
  .site-header { grid-template-columns: 1fr auto; min-height: 58px; padding: 0 15px; }
  .site-header > nav, .brand-category, .header-link:first-child { display: none; }
  .brand strong { font-size: 14px; }
  .brand-mark { width: 29px; height: 29px; }
  .header-actions .header-link + .header-link { border-left: 0; padding-left: 0; }
  main { width: auto; margin: 0 16px; }
  .case-hero { padding: 48px 0 38px; }
  .case-hero h1 { font-size: 37px; }
  .case-hero p { font-size: 14px; }
  .case-index, .case-chain, .strategy-compare { grid-template-columns: 1fr; }
  .case-index a + a { border-top: 1px solid var(--line); border-left: 0; }
  .case-unit { margin-top: 48px; padding-top: 40px; }
  .case-heading { align-items: flex-start; flex-direction: column; gap: 20px; }
  .case-heading h2 { font-size: 27px; }
  .case-result { width: 100%; border-top: 1px solid var(--line); border-left: 0; padding-top: 13px; padding-left: 0; }
  .case-result--double { min-width: 0; }
  .case-chain > div:nth-of-type(even), .case-chain > div:nth-of-type(n+2) { border-top: 1px solid var(--line); border-left: 0; }
  .case-chart > header, .case-chart > footer { align-items: flex-start; flex-direction: column; gap: 8px; }
  .funnel-row { grid-template-columns: 70px minmax(0, 1fr); }
  .revenue-bars { gap: 7px; }
  .compare-bars > span { min-width: 140px; }
  .case-cta { align-items: stretch; flex-direction: column; gap: 22px; }
  .site-footer { grid-template-columns: 1fr auto; padding: 0 16px; }
  .site-footer > span, .site-footer nav a:first-child { display: none; }
}

@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } }