:root {
  --bd-violet: #6D28D9;
  --bd-violet-2: #8B5CF6;
  --bd-violet-deep: #4C1D95;
  --bd-violet-soft: #E4D8FF;
  --bd-navy: #0F1B3A;
  --bd-navy-2: #192A55;
  --bd-mint: #67E8C0;
  --bd-green: #047354;
  --bd-green-soft: #D4EEE1;
  --bd-amber: #92400E;
  --bd-amber-soft: #F7DFC0;
  --bd-ink: #11182F;
  --bd-muted: #3F4B68;
  --bd-line: #BCC3D5;
  --bd-bg: #EEF0F5;
  --bd-surface: #FFFFFF;
  --bd-display: "Plus Jakarta Sans", "Avenir Next", Avenir, system-ui, sans-serif;
  --bd-text: Inter, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  --bd-shadow: 0 18px 48px rgba(15, 27, 58, .12);
}

.bd-page,
.bd-page * { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body.bd-page {
  margin: 0;
  color: var(--bd-ink);
  background: var(--bd-bg);
  font-family: var(--bd-text);
  line-height: 1.65;
  text-rendering: optimizeLegibility;
}

.bd-page img { display: block; max-width: 100%; height: auto; }

.bd-shell {
  width: min(1160px, calc(100% - 40px));
  margin-inline: auto;
}

.bd-hero {
  padding: 0;
  color: #fff;
  background:
    radial-gradient(900px 520px at 82% -8%, rgba(109, 40, 217, .55), transparent 64%),
    radial-gradient(700px 480px at 12% 108%, rgba(103, 232, 192, .22), transparent 65%),
    linear-gradient(145deg, var(--bd-navy), var(--bd-navy-2));
  overflow: hidden;
}

.bd-hero-grid {
  display: grid;
  grid-template-columns: minmax(0, .92fr) minmax(360px, 1.08fr);
  gap: clamp(36px, 6vw, 82px);
  align-items: center;
  padding-block: clamp(52px, 8vw, 96px);
}

.bd-brand {
  display: inline-flex;
  align-items: center;
  gap: 14px;
  color: #fff;
  font: 800 19px/1 var(--bd-display);
  text-decoration: none;
}

.bd-brand img,
.bd-ending img {
  border-radius: 22%;
  box-shadow: 0 8px 22px rgba(0, 0, 0, .24);
}

.bd-eyebrow {
  margin: 30px 0 12px;
  color: var(--bd-mint);
  font: 800 13px/1.2 var(--bd-display);
  letter-spacing: .08em;
  text-transform: uppercase;
}

.bd-hero h1,
.bd-chapter h2,
.bd-ending h2,
.bd-case h3 {
  font-family: var(--bd-display);
  letter-spacing: -.025em;
  text-wrap: balance;
}

.bd-hero h1 {
  margin: 0;
  font-size: clamp(40px, 5.5vw, 72px);
  line-height: 1.02;
}

.bd-intro {
  max-width: 58ch;
  margin: 24px 0 0;
  color: #D5DCF5;
  font-size: clamp(17px, 1.7vw, 20px);
}

.bd-hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 30px;
}

.bd-button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 48px;
  padding: 13px 20px;
  border: 1px solid transparent;
  border-radius: 14px;
  font: 750 15px/1.2 var(--bd-display);
  text-decoration: none;
}

.bd-button-primary {
  color: var(--bd-navy);
  background: var(--bd-mint);
}

.bd-button-secondary {
  color: #fff;
  background: rgba(255, 255, 255, .08);
  border-color: rgba(255, 255, 255, .28);
}

.bd-button:focus-visible,
.bd-toc a:focus-visible,
.bd-source:focus-visible {
  outline: 3px solid var(--bd-mint);
  outline-offset: 3px;
}

.bd-fineprint {
  max-width: 64ch;
  margin: 20px 0 0;
  color: #B9C3E4;
  font-size: 13px;
}

.bd-cover {
  position: relative;
  margin: 0;
  border: 8px solid rgba(255, 255, 255, .9);
  border-radius: 30px;
  overflow: hidden;
  box-shadow: 0 28px 70px rgba(0, 0, 0, .32);
  transform: rotate(1.4deg);
}

.bd-cover::after {
  position: absolute;
  inset: 0;
  content: "";
  box-shadow: inset 0 0 0 1px rgba(15, 27, 58, .1);
  pointer-events: none;
}

.bd-toc {
  position: sticky;
  z-index: 10;
  top: 70px;
  border-bottom: 1px solid var(--bd-line);
  background: rgba(255, 255, 255, .94);
  backdrop-filter: blur(14px);
}

.bd-toc-list {
  display: flex;
  gap: 8px;
  padding-block: 12px;
  overflow-x: auto;
  scrollbar-width: thin;
}

.bd-toc a {
  display: inline-flex;
  flex: none;
  align-items: center;
  gap: 8px;
  padding: 9px 12px;
  border-radius: 999px;
  color: var(--bd-navy);
  background: var(--bd-bg);
  font: 700 13px/1 var(--bd-display);
  text-decoration: none;
}

.bd-toc a span {
  display: grid;
  width: 24px;
  height: 24px;
  place-items: center;
  border-radius: 50%;
  color: #fff;
  background: var(--bd-violet);
}

.bd-main { padding-block: 44px 80px; }

.bd-demo-note {
  margin-bottom: 54px;
  padding: 18px 20px;
  border: 1px solid #9BE0BD;
  border-radius: 15px;
  color: #123E34;
  background: var(--bd-green-soft);
}

.bd-chapter {
  padding: 0;
  scroll-margin-top: 150px;
  margin-bottom: clamp(72px, 10vw, 124px);
}

.bd-chapter-head {
  max-width: 780px;
  margin-bottom: 30px;
}

.bd-chapter-number {
  display: inline-flex;
  padding: 7px 12px;
  border-radius: 999px;
  color: var(--bd-violet-deep);
  background: var(--bd-violet-soft);
  font: 800 12px/1 var(--bd-display);
  letter-spacing: .06em;
  text-transform: uppercase;
}

.bd-chapter h2 {
  margin: 14px 0 8px;
  color: var(--bd-navy);
  font-size: clamp(30px, 4vw, 46px);
  line-height: 1.08;
}

.bd-chapter-head > p {
  margin: 0;
  color: var(--bd-muted);
  font-size: 18px;
}

.bd-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 26px;
  align-items: stretch;
}

.bd-case {
  display: flex;
  min-width: 0;
  margin: 0;
  flex-direction: column;
  overflow: hidden;
  border: 1px solid var(--bd-line);
  border-radius: 20px;
  background: var(--bd-surface);
  box-shadow: var(--bd-shadow);
}

.bd-case > img {
  width: 100%;
  aspect-ratio: 1;
  object-fit: cover;
  border-bottom: 1px solid var(--bd-line);
  background: #E8EAF0;
}

.bd-case figcaption {
  display: flex;
  height: 100%;
  padding: clamp(20px, 3vw, 28px);
  flex-direction: column;
}

.bd-case-title {
  display: grid;
  grid-template-columns: 38px minmax(0, 1fr);
  gap: 12px;
  align-items: center;
}

.bd-case-title > span {
  display: grid;
  width: 38px;
  height: 38px;
  place-items: center;
  border-radius: 12px;
  color: #fff;
  background: linear-gradient(145deg, var(--bd-violet), var(--bd-violet-2));
  font: 800 14px/1 var(--bd-display);
}

.bd-case h3 {
  margin: 0;
  color: var(--bd-navy);
  font-size: 21px;
  line-height: 1.15;
}

.bd-case figcaption > p:not(.bd-dialogue):not(.bd-check) {
  margin: 14px 0 0;
  color: var(--bd-muted);
}

.bd-dialogue {
  position: relative;
  margin: 20px 0 8px;
  padding: 14px 16px;
  border: 1px solid #CBC0F5;
  border-radius: 16px;
  color: var(--bd-navy);
  background: #F4F0FF;
  font-size: 15px;
}

.bd-dialogue::before {
  position: absolute;
  top: -8px;
  left: 24px;
  width: 14px;
  height: 14px;
  border-top: 1px solid #CBC0F5;
  border-left: 1px solid #CBC0F5;
  background: #F4F0FF;
  content: "";
  transform: rotate(45deg);
}

.bd-dialogue strong { color: var(--bd-violet-deep); }

.bd-check {
  margin: 15px 0 0;
  padding: 14px 16px;
  border: 1px solid #E6B46E;
  border-radius: 14px;
  color: #5C2B08;
  background: var(--bd-amber-soft);
  font-size: 14px;
}

.bd-check strong {
  display: block;
  margin-bottom: 3px;
  color: var(--bd-amber);
  font: 800 12px/1.2 var(--bd-display);
  letter-spacing: .06em;
  text-transform: uppercase;
}

.bd-case code {
  padding: 1px 5px;
  border-radius: 5px;
  color: var(--bd-violet-deep);
  background: rgba(109, 40, 217, .09);
  font-size: .92em;
}

.bd-source {
  align-self: flex-start;
  margin-top: auto;
  padding-top: 20px;
  color: var(--bd-violet-deep);
  font: 750 13px/1.35 var(--bd-display);
  text-decoration-thickness: 1px;
  text-underline-offset: 3px;
}

.bd-ending {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  gap: 24px;
  align-items: start;
  padding: clamp(28px, 5vw, 48px);
  border-radius: 24px;
  color: #fff;
  background:
    radial-gradient(600px 300px at 90% 0, rgba(103, 232, 192, .2), transparent 60%),
    linear-gradient(145deg, var(--bd-navy), var(--bd-navy-2));
  box-shadow: var(--bd-shadow);
}

.bd-ending .bd-eyebrow { margin: 0 0 8px; }

.bd-ending h2 {
  margin: 0;
  font-size: clamp(26px, 3.5vw, 40px);
  line-height: 1.1;
}

.bd-ending p:not(.bd-eyebrow) {
  max-width: 68ch;
  color: #D5DCF5;
}

.bd-ending .bd-button { margin-top: 6px; }

.bd-footer {
  padding-block: 30px;
  color: #C6CDE6;
  background: #09132C;
  font-size: 13px;
}

.bd-notice-teaser {
  display: grid;
  grid-template-columns: minmax(0, 1.25fr) minmax(240px, .75fr);
  gap: clamp(24px, 5vw, 58px);
  align-items: center;
  margin-block: clamp(28px, 5vw, 56px);
  padding: clamp(24px, 4vw, 44px);
  border: 1px solid var(--bd-violet-soft);
  border-radius: 24px;
  background:
    radial-gradient(420px 220px at 100% 0, rgba(109, 40, 217, .13), transparent 70%),
    #fff;
  box-shadow: var(--bd-shadow);
}

.bd-notice-teaser h2 {
  margin: 8px 0 12px;
  color: var(--bd-ink);
  font: 800 clamp(25px, 3vw, 38px)/1.12 var(--bd-display);
  letter-spacing: -.025em;
}

.bd-notice-teaser p {
  max-width: 60ch;
  margin: 0 0 22px;
  color: var(--bd-muted);
}

.bd-notice-teaser > a {
  display: block;
  border-radius: 20px;
  overflow: hidden;
  box-shadow: 0 16px 34px rgba(15, 27, 58, .18);
}

.bd-notice-teaser img {
  display: block;
  width: 100%;
  height: auto;
}

@media (max-width: 900px) {
  .bd-hero-grid { grid-template-columns: 1fr; }
  .bd-cover { width: min(680px, 100%); transform: none; }
}

@media (max-width: 720px) {
  .bd-shell { width: min(100% - 30px, 1160px); }
  .bd-grid { grid-template-columns: 1fr; }
  .bd-hero-grid { padding-block: 42px 54px; }
  .bd-hero h1 { font-size: clamp(38px, 12vw, 56px); }
  .bd-chapter-head > p { font-size: 16px; }
  .bd-ending { grid-template-columns: 1fr; }
  .bd-ending img { width: 72px; height: 72px; }
  .bd-notice-teaser { grid-template-columns: 1fr; }
}

@media (max-width: 420px) {
  .bd-shell { width: min(100% - 22px, 1160px); }
  .bd-cover { border-width: 5px; border-radius: 22px; }
  .bd-hero-actions { flex-direction: column; }
  .bd-button { width: 100%; }
  .bd-case { border-radius: 16px; }
  .bd-case figcaption { padding: 20px; }
  .bd-case h3 { font-size: 19px; }
}

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

@media print {
  .bd-toc,
  .bd-hero-actions,
  .bd-source,
  .bd-footer { display: none; }
  .bd-hero { color: var(--bd-ink); background: #fff; }
  .bd-intro,
  .bd-fineprint { color: var(--bd-muted); }
  .bd-cover,
  .bd-case,
  .bd-ending { box-shadow: none; break-inside: avoid; }
  .bd-grid { grid-template-columns: repeat(2, 1fr); }
}