*, *::before, *::after { box-sizing: border-box; }
html, body { margin: 0; padding: 0; height: 100%; }

:root {
  --bg: #fff;
  --ink: #111;
  --muted: #666;
  --rule: #999;
  --pad-x: 8vw;
  --pad-y: 12vh;
  --pad-top: 8vh;
}

html {
  font-size: max(28px, 3.6vmin);
}

body {
  background: var(--bg);
  color: var(--ink);
  font-family: "Roboto Mono", ui-monospace, SFMono-Regular, Menlo, monospace;
  font-weight: 400;
  font-size: 1rem;
  line-height: 1.3;
  overflow: hidden;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

#deck {
  width: 100vw;
  height: 100vh;
  position: relative;
}

section {
  width: 100vw;
  height: 100vh;
  padding: var(--pad-top) var(--pad-x) var(--pad-y);
  display: none;
  flex-direction: column;
  justify-content: flex-start;
  align-items: stretch;
  text-align: left;
  position: relative;
  font-size: calc(1rem * var(--body-scale, 1));
}

section > footer {
  position: absolute;
  bottom: 3.5vh;
  left: 3vw;
  right: 14vw;
  max-width: 100ch;
  font-size: 0.5rem;
  font-weight: 400;
  color: var(--muted);
  letter-spacing: 0.02em;
  line-height: 1.4;
  text-align: left;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

section.active { display: flex; }

section.divider {
  justify-content: center;
  align-items: center;
  text-align: center;
}

.author {
  margin: 2.5rem 0 0;
  font-size: 0.75rem;
  font-weight: 400;
  color: var(--muted);
  letter-spacing: 0.04em;
  line-height: 1.8;
  font-family: "Roboto Mono", "PingFang TC", "Noto Sans CJK TC", "Hiragino Sans GB", "Microsoft JhengHei", monospace;
  text-align: center;
  max-width: 92vw;
}

.author .sep {
  color: var(--rule);
  margin: 0 0.6em;
}

.author a {
  color: inherit;
  text-decoration: none;
  transition: color 120ms;
}

.author a:hover,
.author a:focus-visible {
  color: var(--ink);
  outline: none;
}

section.outline {
  justify-content: center;
  align-items: center;
}

section.pic-caption {
  flex-direction: row;
  align-items: center;
  gap: 5vw;
  text-align: left;
}

section.pic-caption > .pic-caption-text {
  flex: 1 1 0;
  min-width: 0;
  font-size: 0.8em;
}

section.pic-caption > .pic-caption-image {
  flex: 1.2 1 0;
  min-width: 0;
  margin: 0;
  display: flex;
  flex-direction: column;
  gap: 0.6em;
}

section.pic-caption svg,
section.pic-caption img {
  width: 100%;
  height: auto;
  display: block;
  border: 1px solid var(--rule);
  background: #fff;
}

section.pic-caption figcaption {
  font-size: 0.75em;
  font-weight: 400;
  color: var(--muted);
  letter-spacing: 0.02em;
}

.outline-grid {
  display: grid;
  grid-template-columns: auto auto;
  column-gap: 8vw;
  align-items: start;
}

.outline-label {
  font-size: 2rem;
  font-weight: 700;
  letter-spacing: 0.15em;
  line-height: 1;
  color: var(--ink);
}

.outline-list {
  list-style: none;
  padding: 0;
  margin: 0;
  counter-reset: outline-item;
}

.outline-list li {
  counter-increment: outline-item;
  position: relative;
  padding-left: 3em;
  margin-bottom: 0.6em;
  font-size: 1.4rem;
  font-weight: 600;
  line-height: 1.2;
}

.outline-list li::before {
  content: counter(outline-item, decimal-leading-zero);
  position: absolute;
  left: 0;
  color: var(--rule);
  font-weight: 400;
}

.outline-list a {
  color: var(--ink);
  text-decoration: none;
}

.outline-list a:hover,
.outline-list a:focus-visible {
  text-decoration: underline;
  text-underline-offset: 0.3em;
  outline: none;
}

h1 {
  font-size: 2rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  line-height: 1.1;
  margin: 0;
}

h2 {
  font-size: 1.6rem;
  font-weight: 600;
  letter-spacing: -0.01em;
  line-height: 1.15;
  margin: 0;
}

h3 {
  font-size: 1.4rem;
  font-weight: 600;
  color: var(--ink);
  letter-spacing: -0.005em;
  line-height: 1.2;
  margin: 0;
}

h3[data-parent]::before {
  content: attr(data-parent) " · ";
  color: var(--rule);
  font-weight: 400;
}

h5 {
  font-size: 1rem;
  font-weight: 600;
  color: var(--ink);
  letter-spacing: 0.01em;
  line-height: 1.2;
  margin: 0 0 0.5rem;
}

h6 {
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--rule);
  letter-spacing: 0.01em;
  margin: 0.3rem 0 0.5rem;
}

h6:empty::before { content: "—"; visibility: hidden; }

p {
  max-width: 64ch;
  margin: 0 0 1em;
}

ul, ol, dl {
  margin: 0;
  padding: 0;
  list-style: none;
  max-width: 70ch;
}

ul li, ol li {
  position: relative;
  padding-left: 1.5em;
  margin-bottom: 0.5em;
}

ul li::before {
  content: "·";
  position: absolute;
  left: 0.3em;
  color: var(--muted);
}

ol { counter-reset: item; }
ol li { counter-increment: item; }
ol li::before {
  content: counter(item, decimal-leading-zero) ".";
  position: absolute;
  left: 0;
  color: var(--muted);
}

dl {
  display: grid;
  grid-template-columns: max-content 1fr;
  gap: 0.5em 2em;
}

dt { color: var(--ink); }
dd { margin: 0; color: var(--muted); }

pre {
  margin: 0;
  padding: 1.25em 1.5em;
  border-left: 1px solid var(--rule);
  background: transparent;
  overflow-x: auto;
  font-size: 0.9em;
  line-height: 1.3;
}

code { font-family: inherit; }

blockquote {
  margin: 0;
  padding: 0 0 0 1.5em;
  border-left: 1px solid var(--rule);
  max-width: 60ch;
}

blockquote p {
  font-size: 1.5em;
  font-weight: 300;
  line-height: 1.3;
  margin: 0 0 1em;
}

cite {
  font-style: normal;
  font-size: 0.875em;
  color: var(--muted);
}
cite::before { content: "— "; }

.callout {
  margin: 1em 0;
  padding: 0.75em 0;
  border-top: 1px solid var(--rule);
  border-bottom: 1px solid var(--rule);
  max-width: 70ch;
}

.callout + .callout {
  margin-top: 1.25em;
}

.callout-label {
  display: inline-block;
  font-size: 0.75em;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--ink);
  margin-right: 0.85em;
  vertical-align: baseline;
}

.callout p {
  display: inline;
  margin: 0;
  color: var(--ink);
}

.callout p + p {
  display: block;
  margin-top: 0.5em;
}

.callout.warn { border-top-color: var(--ink); }
.callout.warn .callout-label { color: var(--ink); }

table {
  width: 100%;
  max-width: 80ch;
  border-collapse: collapse;
  border-spacing: 0;
  font-size: 1em;
  font-variant-numeric: tabular-nums;
}

caption {
  caption-side: bottom;
  text-align: left;
  font-size: 0.875em;
  font-weight: 300;
  color: var(--muted);
  padding-top: 0.75em;
  letter-spacing: 0.01em;
}
caption::before { content: "— "; }

thead th {
  text-align: left;
  font-weight: 600;
  color: var(--ink);
  padding: 0.3em 1.2em 0.3em 0;
  border-bottom: 1px solid var(--ink);
  letter-spacing: 0.04em;
  white-space: nowrap;
}

tbody td {
  padding: 0.3em 1.2em;
  border-bottom: 1px solid var(--rule);
  color: var(--ink);
  vertical-align: baseline;
}

tbody tr:last-child td {
  border-bottom: 1px solid var(--ink);
}

th:first-child, td:first-child { padding-left: 0; }
th:last-child,  td:last-child  { padding-right: 0; }

th.num, td.num {
  text-align: right;
  font-variant-numeric: tabular-nums;
}

.cols {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 4vw;
  width: 100%;
}

.cols > div {
  min-width: 0;
}

.cols > div h5 {
  margin-top: 0;
  margin-bottom: 1rem;
}

#chapters {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 10;
  display: flex;
  flex-wrap: wrap;
  gap: 0;
  padding: 1rem 3vw 0;
  font-size: 0.5rem;
  pointer-events: none;
}

#chapters a:nth-child(n+3)::before {
  content: "·";
  color: var(--rule);
  margin: 0 0.6em;
  display: inline-block;
  text-decoration: none;
}

#chapters a {
  color: var(--muted);
  text-decoration: none;
  letter-spacing: 0.05em;
  pointer-events: auto;
  transition: color 100ms;
}

#chapters a:first-child {
  margin-right: auto;
}

#chapters a:hover,
#chapters a:focus-visible {
  color: var(--ink);
  outline: none;
}

#chapters a.active {
  color: var(--ink);
  font-weight: 600;
  text-decoration: underline;
  text-underline-offset: 0.35em;
  text-decoration-thickness: 1px;
}

footer {
  position: fixed;
  bottom: 0;
  left: 0;
  right: 0;
  pointer-events: none;
  z-index: 10;
}

#page-number {
  position: absolute;
  right: 3vw;
  bottom: 3.5vh;
  font-size: 0.5rem;
  color: var(--muted);
  letter-spacing: 0.05em;
}

#progress {
  height: 5px;
  width: 100%;
  border-top: 1px solid var(--rule);
  background: transparent;
}

#progress-fill {
  height: 100%;
  width: 0;
  background: var(--ink);
  transition: width 120ms linear;
}

body.overview {
  overflow: auto;
}

body.overview #deck {
  width: 100%;
  height: auto;
  min-height: 100vh;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 2vw;
  padding: 4vw;
}

body.overview section {
  display: flex !important;
  width: 100%;
  height: auto;
  aspect-ratio: 16 / 9;
  padding: 1.5vw 2vw;
  border: 1px solid var(--rule);
  cursor: pointer;
  pointer-events: auto;
  overflow: hidden;
}

body.overview section h1 { font-size: 1.2rem; }
body.overview section h2 { font-size: 0.9rem; }
body.overview section h6 {
  font-size: 0.6rem;
  margin: 0.25rem 0 0.5rem;
}
body.overview section p,
body.overview section li,
body.overview section dt,
body.overview section dd,
body.overview section pre,
body.overview section table,
body.overview section th,
body.overview section td,
body.overview section blockquote p {
  font-size: 0.6rem;
  line-height: 1.3;
  margin-bottom: 0.2rem;
}

body.overview section th,
body.overview section td {
  padding: 0.05rem 0.4rem 0.05rem 0;
}

body.overview section.active {
  outline: 2px solid var(--ink);
  outline-offset: -2px;
}

body.overview footer,
body.overview section > footer,
body.overview #chapters { display: none; }

@media screen {
  body.cover #chapters,
  body.cover #page-number { display: none; }
}

@media print {
  /* Render the PDF at virtual 1080p so screen typography (rem, vh, vw) maps 1:1.
     The PDF reader scales the page to whatever physical size it needs at print time. */
  @page {
    size: 1920px 1080px;
    margin: 0;
  }

  html, body {
    height: auto;
    margin: 0;
    overflow: visible;
    background: #fff;
  }

  /* The screen body footer (fixed page number + progress bar) shows ONE state.
     For per-page numbering in print we replace it with section::after + section background gradient below. */
  body > footer { display: none; }

  /* #deck no longer constrains to one viewport — sections stack across pages. */
  #deck {
    height: auto;
    display: block;
  }

  /* Force every section to render at full page size, one per printed page. */
  section {
    display: flex !important;
    page-break-after: always;
    break-after: page;
    page-break-inside: avoid;
    break-inside: avoid;
    /* Per-page progress bar: hairline rule at 5px above bottom, fill from left to --progress. */
    background-image:
      linear-gradient(var(--rule), var(--rule)),
      linear-gradient(
        to right,
        var(--ink) 0 var(--progress, 0%),
        transparent var(--progress, 0%) 100%
      );
    background-position: 0 calc(100% - 5px), 0 100%;
    background-size: 100% 1px, 100% 5px;
    background-repeat: no-repeat, no-repeat;
    -webkit-print-color-adjust: exact;
    print-color-adjust: exact;
  }

  section:last-child {
    page-break-after: auto;
    break-after: auto;
  }

  /* Per-page page number — uses the same coords as the screen #page-number so layout is 1:1. */
  section::after {
    content: attr(data-num) " / " attr(data-total);
    position: absolute;
    right: 3vw;
    bottom: 3.5vh;
    font-size: 0.5rem;
    color: var(--muted);
    letter-spacing: 0.05em;
  }

  /* Menubar already position:fixed via the screen rule — fixed elements repeat on every printed page.
     Solid white background so it never visually merges into a slide with edge-to-edge content. */
  #chapters {
    background: #fff;
  }
}