/* System type, a reading rule and a small set of spacing utilities. */
:root {
  color-scheme: light;
  --paper: #ffffff;
  --ink: #111827;
  --muted: #4b5563;
  --blue: #3b82f6;
  --link: #1d4ed8;
  --violet: #8b5cf6;
  --violet-ink: #6d28d9;
  --green: #16a34a;
  --amber: #d97706;
  --red: #dc2626;
  --rule: #dbe1e9;
  --sans: Inter, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  --display: Didot, "Bodoni 72", "Iowan Old Style", "Palatino Linotype", Georgia, serif;
  --mono: "JetBrains Mono", ui-monospace, "SFMono-Regular", Consolas, monospace;
}
* { box-sizing: border-box; }
html { scroll-padding-top: 24px; scroll-padding-bottom: 112px; }
body { margin: 0; background: var(--paper); color: var(--ink); font-size: 18px; line-height: 1.65; }
body, button, input, summary { font-family: var(--sans); }
h1, h2, h3, p, figure { margin: 0; }
h1, h2, h3 { text-wrap: balance; overflow-wrap: break-word; }
h2, h3 { font-size: clamp(32px, 3.2vw, 44px); line-height: 1.16; font-weight: 600; letter-spacing: -.025em; }
a { color: var(--link); text-decoration-color: var(--blue); text-underline-offset: 5px; text-decoration-thickness: 1.5px; }
a:hover { color: var(--violet-ink); text-decoration-color: var(--violet); }
a:active { color: var(--ink); }
button { font-size: 16px; cursor: pointer; }
button, a, summary { -webkit-tap-highlight-color: #dbeafe; }
:focus-visible { outline: 3px solid #111827; outline-offset: 4px; box-shadow: 0 0 0 7px #fff; border-radius: 4px; }
main:focus { outline: none; }
button:disabled { cursor: default; opacity: .65; }
[hidden] { display: none !important; }
img { display: block; max-width: 100%; height: auto; }
code, pre { font-family: var(--mono); font-size: 16px; }
.u-page { width: min(1216px, calc(100% - 96px)); margin-inline: auto; }
.u-sans { font-family: var(--sans); }
.u-display { font-family: var(--display); }
.u-copy { max-width: 66ch; font-size: 18px; line-height: 1.75; overflow-wrap: break-word; }
.u-small { font-size: 16px; line-height: 1.6; }
.u-lead { font-size: 20px; line-height: 1.65; max-width: 58ch; }
.u-strong { font-weight: 650; }
.u-muted { color: var(--muted); }
.u-violet { color: var(--violet-ink); }
.u-stack-8 > * + * { margin-top: 8px; }
.u-stack-12 > * + * { margin-top: 12px; }
.u-stack-16 > * + * { margin-top: 16px; }
.u-stack-24 > * + * { margin-top: 24px; }
.u-stack-64 > * + * { margin-top: 64px; }
.u-wrap { display: flex; flex-wrap: wrap; align-items: center; }
.u-between { justify-content: space-between; }
.u-gap-16 { gap: 16px; }
.u-gap-24 { gap: 24px; }
.u-rule-top { border-top: 1px solid var(--rule); }
.u-tap { min-height: 44px; min-width: 44px; }
.u-link { font-size: 16px; line-height: 1.5; }
.u-button { display: inline-flex; align-items: center; justify-content: center; gap: 12px; padding: 12px 20px; border: 1px solid #cbd5e1; border-radius: 8px; background: #fff; color: var(--ink); font-weight: 650; text-decoration: none; }
.u-button:hover { border-color: var(--violet-ink); background: #f5f3ff; color: var(--ink); }
.u-button:active { background: #ede9fe; }
.u-button-blue { background: var(--blue); color: var(--ink); border-color: var(--blue); }
.u-button-blue:hover { background: #dbeafe; border-color: var(--link); color: var(--ink); }
.u-panel-blue { background: #eff6ff; border-left: 4px solid var(--blue); padding: 20px 24px; }
.u-panel-soft { background: #f7f6fb; padding: 24px; border-radius: 0 8px 8px 0; }
.u-panel-caution { background: #fffbeb; border-left: 4px solid var(--amber); padding: 28px 32px; }
.u-panel-danger { background: #fef2f2; border-left: 4px solid var(--red); padding: 28px 32px; }
.u-hero-grid { display: grid; grid-template-columns: minmax(0, 1.55fr) minmax(0, 1fr); gap: 48px; align-items: center; }
.u-hero-single { max-width: 920px; }
.u-home-title { font-size: clamp(52px, 5.8vw, 84px); line-height: 1.04; letter-spacing: -.045em; font-weight: 600; max-width: 13.8ch; text-wrap: initial; }
.u-note-title { font-size: clamp(48px, 5.4vw, 76px); line-height: 1.08; letter-spacing: -.04em; font-weight: 600; max-width: 20ch; }
.u-image { width: 100%; max-width: 512px; }
.u-visually-hidden { position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px; overflow: hidden; clip-path: inset(50%); white-space: nowrap; border: 0; }
.skip-link { position: fixed; z-index: 40; left: 24px; top: 12px; transform: translateY(-160%); background: #fff; padding: 12px 16px; border: 2px solid var(--ink); font-size: 16px; }
.skip-link:focus { transform: translateY(0); }
.notebook-masthead { padding-block: 24px; border-bottom: 1px solid var(--rule); }
.notebook-name { display: inline-flex; align-items: center; gap: 12px; color: var(--ink); text-decoration: none; }
.book-sign { width: 28px; height: 24px; border: 1.5px solid var(--ink); border-radius: 2px 7px 7px 2px; position: relative; flex: none; }
.book-sign::before { content: ""; position: absolute; left: 7px; top: -1.5px; bottom: -1.5px; border-left: 2px solid var(--blue); }
.book-sign::after { content: ""; position: absolute; width: 7px; height: 6px; border-top: 1.5px solid var(--violet); border-bottom: 1.5px solid var(--violet); right: 5px; top: 6px; }
.language-toggle { font-weight: 550; padding-inline: 16px; }
.language-toggle[aria-pressed="true"] { background: #ede9fe; border-color: var(--violet-ink); }
.language-sign, .plain-sign { font-family: var(--sans); font-size: 24px; line-height: 1; }
.note-opening { padding-block: 64px 48px; }
.chapter-label { letter-spacing: .025em; }
.notebook-drawing { padding-top: 48px; }
.notebook-drawing figcaption { max-width: 32ch; padding-left: 16px; border-left: 2px solid var(--violet); }
.front-cover .notebook-drawing { align-self: center; }
.state-anchor { max-width: 62ch; }
.state-anchor .care-answer { font-size: 18px; line-height: 1.65; }
.source-drawer { max-width: 68ch; }
.source-handle, .plain-note > summary { display: flex; align-items: center; gap: 16px; justify-content: space-between; font-size: 16px; line-height: 1.5; cursor: pointer; padding: 12px 4px; list-style: none; font-weight: 550; }
.source-handle::-webkit-details-marker, .plain-note > summary::-webkit-details-marker { display: none; }
.source-handle:hover, .plain-note > summary:hover { color: var(--violet-ink); }
.drawer-mark { font-family: var(--sans); width: 24px; height: 24px; display: inline-flex; align-items: center; justify-content: center; color: var(--link); font-size: 24px; flex: none; }
details[open] > summary .drawer-mark { transform: rotate(45deg); }
.source-body { padding: 16px 20px; margin-bottom: 8px; }
.state-anchor .source-body { background: #fff; }
.source-label { color: var(--muted); }
.u-source-link { width: 100%; justify-content: space-between; }
.note-link { display: inline-flex; align-items: center; gap: 16px; padding-block: 12px; max-width: 100%; }
.link-direction { flex: none; text-decoration: none; }
.note-link.u-button { padding: 12px 20px; }
.plain-words { max-width: 760px; margin-block: 0 64px; }
.plain-note > summary { justify-content: flex-start; color: var(--violet-ink); }
.plain-note .drawer-mark { margin-left: auto; }
.plain-note[open] { border-bottom: 1px solid var(--rule); padding-bottom: 12px; }
.note-body { max-width: 880px; padding-left: 48px; margin-left: 8px; border-left: 1px solid #bfdbfe; }
.care-section { position: relative; max-width: 760px; }
.care-section::before { content: ""; position: absolute; width: 9px; height: 9px; border: 2px solid var(--blue); background: var(--paper); border-radius: 50%; left: -53px; top: 9px; }
.section-beat { letter-spacing: .025em; }
.as-of { display: inline-flex; align-items: center; gap: 8px; }
.date-mark { display: inline-block; width: 8px; height: 8px; border-radius: 50%; background: var(--green); flex: none; }
.care-section.u-panel-danger::before { border-color: var(--red); }
.care-section.u-panel-caution::before { border-color: var(--amber); }
.next-note { max-width: 880px; margin-block: 80px; padding: 40px 48px; border-left: 4px solid var(--violet); }
.notebook-footer { padding-block: 32px 144px; max-width: 920px; }
.notebook-footer p { max-width: 66ch; }
.notebook-footer .footer-links { row-gap: 8px; }
.chapter-rows { border-bottom: 1px solid var(--rule); }
.chapter-row { display: grid; grid-template-columns: minmax(180px, .8fr) minmax(0, 1.2fr) 24px; gap: 24px; align-items: center; padding: 20px 12px 20px 0; border-top: 1px solid var(--rule); text-decoration: none; color: var(--ink); }
.chapter-row:hover { background: #eff6ff; color: var(--link); }
.row-title { font-size: 18px; }
.row-tease { font-size: 16px; }
.row-arrow { color: var(--link); }
.bottom-dock { position: fixed; bottom: 16px; left: 50%; transform: translateX(-50%); z-index: 20; width: min(620px, calc(100% - 32px)); background: #fff; border: 1px solid #cbd5e1; border-radius: 16px; box-shadow: 0 8px 32px #11182714; padding: 8px; }
.dock-pages { display: grid; grid-template-columns: repeat(5, minmax(0, 1fr)); gap: 4px; }
.dock-link { font-size: 16px; display: flex; flex-direction: column; gap: 4px; justify-content: center; align-items: center; padding: 8px 4px; color: var(--muted); text-decoration: none; border-radius: 8px; line-height: 1.4; min-height: 60px; }
.dock-link:hover { background: #f5f3ff; color: var(--violet-ink); }
.dock-link.is-selected { background: #eff6ff; color: #1e40af; box-shadow: inset 0 -2px var(--blue); }
.dock-icon { display: block; width: 20px; height: 18px; position: relative; color: currentColor; }
.icon-book { border: 1.5px solid currentColor; border-radius: 2px 4px 4px 2px; }
.icon-book::after { content: ""; position: absolute; left: 6px; top: -1px; bottom: -1px; border-left: 1.5px solid currentColor; }
.icon-route::before { content: ""; position: absolute; width: 16px; height: 10px; top: 4px; left: 2px; border: 1.5px solid currentColor; border-left-color: transparent; border-right-color: transparent; border-radius: 50%; transform: rotate(-30deg); }
.icon-route::after { content: ""; position: absolute; right: 0; top: 0; width: 5px; height: 5px; background: currentColor; border-radius: 50%; }
.icon-check { border: 1.5px solid currentColor; border-radius: 50%; width: 18px; }
.icon-check::after { content: ""; position: absolute; left: 4px; top: 4px; width: 7px; height: 4px; border-left: 1.5px solid currentColor; border-bottom: 1.5px solid currentColor; transform: rotate(-45deg); }
.icon-note { border: 1.5px solid currentColor; border-radius: 2px; width: 16px; margin-inline: 2px; }
.icon-note::after { content: ""; position: absolute; left: 3px; right: 3px; top: 4px; height: 6px; border-top: 1.5px solid currentColor; border-bottom: 1.5px solid currentColor; }
.icon-pages { border: 1.5px solid currentColor; border-radius: 2px; width: 15px; margin-left: 2px; }
.icon-pages::after { content: ""; position: absolute; top: -4px; right: -5px; bottom: 2px; width: 12px; border-top: 1.5px solid currentColor; border-right: 1.5px solid currentColor; border-radius: 0 2px 0 0; }
@media (max-width: 900px) {
  .u-page { width: calc(100% - 64px); }
  .u-hero-grid { grid-template-columns: minmax(0, 1fr); gap: 24px; }
  .notebook-drawing { max-width: 360px; padding-top: 0; justify-self: end; }
  .front-cover .notebook-drawing { display: none; }
  .note-opening { padding-top: 48px; }
  .note-body { padding-left: 32px; }
  .care-section::before { left: -37px; }
}
@media (max-width: 600px) {
  .u-page { width: calc(100% - 40px); }
  .u-copy { font-size: 18px; line-height: 1.7; }
  .u-lead { font-size: 18px; }
  .notebook-masthead { padding-block: 16px; gap: 12px; }
  .notebook-name { font-size: 16px; }
  .language-control { width: 100%; }
  .language-toggle { padding: 10px 12px; min-height: 44px; font-size: 16px; }
  .language-sign { font-size: 22px; }
  .note-opening { padding-block: 32px; }
  .opening-words > * + * { margin-top: 20px; }
  .u-home-title { font-size: 52px; max-width: 13ch; line-height: 1.04; letter-spacing: -.04em; }
  .u-note-title { font-size: 48px; max-width: 15ch; }
  .u-panel-blue { padding: 16px; }
  .state-anchor .care-answer { font-size: 16px; }
  .plain-words { margin-bottom: 48px; }
  .plain-note > summary { gap: 12px; }
  .note-body { margin-left: 4px; padding-left: 20px; }
  .care-section::before { left: -25px; }
  .u-stack-64 > * + * { margin-top: 48px; }
  .u-panel-caution, .u-panel-danger { padding: 20px 16px; }
  .u-panel-caution::before, .u-panel-danger::before { left: -29px; }
  .source-body { padding: 16px; }
  .source-handle { padding-inline: 0; }
  .u-source-link { align-items: flex-start; }
  .next-note { margin-block: 56px 48px; padding: 28px 24px; }
  .next-note .u-button { width: 100%; justify-content: space-between; text-align: left; }
  .chapter-row { grid-template-columns: minmax(0, 1fr) 20px; gap: 8px 16px; padding-block: 20px; }
  .row-tease { grid-row: 2; grid-column: 1; }
  .row-arrow { grid-column: 2; grid-row: 1 / span 2; }
  .notebook-drawing { max-width: 280px; }
  .bottom-dock { width: calc(100% - 16px); bottom: max(8px, env(safe-area-inset-bottom)); padding: 4px; border-radius: 12px; }
  .dock-pages { gap: 0; }
  .dock-link { min-height: 64px; padding-inline: 0; font-size: 16px; letter-spacing: -.02em; }
  .notebook-footer { padding-bottom: 128px; }
  .footer-links { flex-direction: column; align-items: flex-start; gap: 4px; }
}
@media (prefers-reduced-motion: no-preference) {
  a, button { transition: background-color 120ms ease, color 120ms ease, border-color 120ms ease; }
  .drawer-mark { transition: transform 120ms ease; }
}
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { animation: none !important; transition: none !important; scroll-behavior: auto !important; }
}
@media print {
  .bottom-dock, .language-control, .skip-link, .footer-links { display: none; }
  .u-page { width: 100%; }
  .note-body { border-left: none; padding-left: 0; margin-left: 0; }
  .care-section::before { display: none; }
  .notebook-footer { padding-bottom: 0; }
  .next-note { break-inside: avoid; }
}