:root {
  --bg: #f4f5f7;
  --surface: #ffffff;
  --surface-soft: #f8fafc;
  --text: #172033;
  --muted: #5b667a;
  --border: #dfe3ea;
  --blue: #2563eb;
  --blue-dark: #1d4ed8;
  --blue-soft: #eaf1ff;
  --green-soft: #ecfdf3;
  --green: #16a34a;
  --shadow: 0 18px 50px rgba(23, 32, 51, 0.08);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family:
    "Noto Sans JP",
    system-ui,
    -apple-system,
    BlinkMacSystemFont,
    "Segoe UI",
    sans-serif;
  line-height: 1.75;
}

a {
  color: inherit;
  text-decoration: none;
}

.docs-topbar {
  position: sticky;
  top: 0;
  z-index: 20;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  min-height: 68px;
  padding: 12px clamp(18px, 4vw, 48px);
  border-bottom: 1px solid var(--border);
  background: rgba(255, 255, 255, 0.94);
  backdrop-filter: blur(14px);
}

.docs-brand img {
  display: block;
  width: 164px;
  height: auto;
}

.docs-topbar nav {
  display: flex;
  align-items: center;
  gap: 18px;
  color: var(--muted);
  font-size: 14px;
  font-weight: 800;
}

.topbar-cta,
.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 42px;
  padding: 0 16px;
  border-radius: 8px;
  font-weight: 900;
  white-space: nowrap;
}

.topbar-cta,
.button.primary {
  background: var(--blue);
  color: #fff;
  box-shadow: 0 10px 22px rgba(37, 99, 235, 0.2);
}

.button.secondary {
  border: 1px solid var(--border);
  background: #fff;
}

.docs-shell {
  display: grid;
  grid-template-columns: 260px minmax(0, 1fr);
  width: min(1280px, 100%);
  margin: 0 auto;
}

.docs-sidebar {
  position: sticky;
  top: 68px;
  align-self: start;
  height: calc(100vh - 68px);
  padding: 28px 24px;
  border-right: 1px solid var(--border);
  background: #fff;
  overflow: auto;
}

.sidebar-title {
  margin-bottom: 14px;
  color: var(--text);
  font-size: 13px;
  font-weight: 900;
}

.docs-sidebar a {
  display: block;
  padding: 8px 10px;
  border-radius: 8px;
  color: var(--muted);
  font-size: 14px;
  font-weight: 800;
}

.docs-sidebar a:hover {
  background: var(--blue-soft);
  color: var(--blue-dark);
}

.docs-main {
  min-width: 0;
  padding: 48px clamp(22px, 5vw, 64px) 80px;
}

.docs-hero,
.doc-section {
  max-width: 920px;
}

.docs-hero {
  padding: 20px 0 56px;
}

.eyebrow {
  margin: 0 0 10px;
  color: var(--blue);
  font-size: 13px;
  font-weight: 900;
}

h1,
h2,
h3,
p {
  margin-top: 0;
}

h1 {
  margin-bottom: 18px;
  font-size: clamp(36px, 5vw, 58px);
  line-height: 1.15;
}

h2 {
  margin-bottom: 14px;
  font-size: clamp(26px, 3vw, 36px);
  line-height: 1.28;
}

h3 {
  margin-bottom: 8px;
  font-size: 18px;
}

.docs-hero > p,
.section-heading > p,
.workflow p,
.next-action p,
figcaption {
  color: var(--muted);
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 26px;
}

.doc-section {
  padding: 54px 0;
  border-top: 1px solid var(--border);
}

.section-heading {
  max-width: 760px;
  margin-bottom: 24px;
}

.doc-figure {
  margin: 0 0 24px;
  padding: 14px;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: var(--surface);
  box-shadow: var(--shadow);
}

.doc-figure img {
  display: block;
  width: 100%;
  height: auto;
  border: 1px solid var(--border);
  border-radius: 8px;
}

figcaption {
  margin-top: 10px;
  font-size: 13px;
}

.callout {
  padding: 18px;
  border: 1px solid #b7cdfc;
  border-radius: 8px;
  background: #f7fbff;
}

.callout strong {
  display: block;
  margin-bottom: 6px;
  color: var(--blue-dark);
}

.callout p {
  margin-bottom: 0;
  color: var(--muted);
}

.steps {
  display: grid;
  gap: 10px;
  margin: 0;
  padding-left: 24px;
}

.steps li {
  padding-left: 4px;
}

.workflow {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 14px;
}

.workflow article {
  padding: 20px;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: #fff;
}

.workflow span {
  display: grid;
  place-items: center;
  width: 34px;
  height: 34px;
  margin-bottom: 14px;
  border-radius: 50%;
  background: var(--blue);
  color: #fff;
  font-weight: 900;
}

.next-action {
  margin-top: 34px;
  padding: clamp(24px, 4vw, 38px);
  border-radius: 8px;
  background: #102042;
  color: #fff;
}

.next-action p {
  color: #d8e3f8;
}

@media (max-width: 900px) {
  .docs-shell {
    grid-template-columns: 1fr;
  }

  .docs-sidebar {
    position: static;
    display: flex;
    gap: 6px;
    height: auto;
    padding: 12px 16px;
    border-right: 0;
    border-bottom: 1px solid var(--border);
    overflow: auto;
  }

  .sidebar-title {
    display: none;
  }

  .docs-sidebar a {
    flex: 0 0 auto;
  }
}

@media (max-width: 640px) {
  .docs-topbar {
    align-items: flex-start;
    flex-direction: column;
  }

  .docs-topbar nav {
    width: 100%;
    justify-content: space-between;
  }

  .docs-main {
    padding: 34px 16px 64px;
  }

  .workflow {
    grid-template-columns: 1fr;
  }
}