/* Theme */
:root {
  --ink: #101a2e;
  --muted: #60708b;
  --paper: #f6f3ec;
  --panel: #fffdf8;
  --line: #c9cfca;
  --lime: #c9f24b;
  --coral: #ff7961;
  --blue: #96c1ff;
  --alt: #eef3ed;
  --copy: #3c4a61;
  --copy2: #536177;
  --visual: #e8ede9;
  --serif: ui-serif, Georgia, Cambria, "Times New Roman", serif;
  --sans: Inter, ui-sans-serif, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  --mono: "SFMono-Regular", Consolas, "Liberation Mono", monospace;
  color-scheme: light;
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --ink: #ece8de;
    --muted: #95a0b4;
    --paper: #11151d;
    --panel: #171c26;
    --line: #2d3543;
    --alt: #1b2230;
    --copy: #c3cad6;
    --copy2: #a7b0c0;
    --visual: #1e2531;
    color-scheme: dark;
  }
}

:root[data-theme="dark"] {
  --ink: #ece8de;
  --muted: #95a0b4;
  --paper: #11151d;
  --panel: #171c26;
  --line: #2d3543;
  --alt: #1b2230;
  --copy: #c3cad6;
  --copy2: #a7b0c0;
  --visual: #1e2531;
  color-scheme: dark;
}

/* Base */
* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  min-width: 0;
  margin: 0;
  overflow-x: hidden;
  background: var(--paper);
  color: var(--ink);
  font: 16px/1.5 var(--sans);
}

a {
  color: inherit;
}

.shell {
  width: min(1460px, calc(100% - 48px));
  min-width: 0;
  margin: 0 auto;
}

.skip-link {
  position: absolute;
  z-index: 20;
  top: -50px;
  left: 10px;
  padding: 8px;
  background: var(--lime);
}

.skip-link:focus {
  top: 10px;
}

/* Header and tabs */
.masthead {
  position: sticky;
  z-index: 5;
  top: 0;
  padding: 14px 0 0;
  border-bottom: 1px solid var(--ink);
  background: var(--paper);
}

.masthead .shell {
  display: flex;
  min-width: 0;
  flex-wrap: wrap;
  gap: 28px;
  align-items: flex-end;
  justify-content: space-between;
}

.brand {
  display: flex;
  min-width: 0;
  gap: 14px;
  align-items: baseline;
  padding-bottom: 14px;
  text-decoration: none;
}

.brand-mark {
  color: var(--muted);
  font: 700 12px/1 var(--mono);
  letter-spacing: .08em;
}

.brand-name {
  font: 700 17px/1 var(--sans);
  letter-spacing: -.03em;
}

.tabs {
  display: flex;
  max-width: 100%;
  min-width: 0;
  gap: 0;
}

.tab {
  padding: 10px 16px 12px;
  border: 1px solid transparent;
  border-bottom: 0;
  background: transparent;
  color: var(--muted);
  font: 700 12px/1 var(--mono);
  letter-spacing: .06em;
  text-decoration: none;
  text-transform: uppercase;
  white-space: nowrap;
}

.tab:hover,
.tab[aria-selected="true"] {
  color: var(--ink);
}

.tab[aria-selected="true"] {
  margin-bottom: -1px;
  border-color: var(--ink);
  background: var(--panel);
  box-shadow: inset 0 3px 0 var(--lime);
}

.theme-btn {
  min-height: 30px;
  margin: 0 0 8px 12px;
  padding: 0 10px;
  border: 1px solid var(--ink);
  border-radius: 999px;
  background: transparent;
  color: var(--ink);
  font: 700 11px/1 var(--mono);
  cursor: pointer;
}

/* Landing */
.hero {
  padding: clamp(40px, 7vw, 96px) 0 34px;
  border-bottom: 1px solid var(--ink);
}

.eyebrow,
.section-label {
  margin: 0 0 15px;
  color: var(--muted);
  font: 700 11px/1 var(--mono);
  letter-spacing: .11em;
  text-transform: uppercase;
}

h1 {
  max-width: 1000px;
  margin: 0;
  font: 500 clamp(40px, 7vw, 96px)/.92 var(--serif);
  letter-spacing: -.065em;
}

h2 {
  font: 500 clamp(27px, 4vw, 48px)/1 var(--serif);
  letter-spacing: -.05em;
}

h3 {
  font-family: var(--serif);
}

.hero-copy {
  max-width: 690px;
  margin: 34px 0 0;
  overflow-wrap: anywhere;
  font-size: clamp(17px, 2vw, 22px);
  line-height: 1.35;
  letter-spacing: -.025em;
}

.stamps {
  display: flex;
  flex-wrap: wrap;
  gap: 26px;
  margin-top: 28px;
}

.library-stamp {
  padding: 16px 0 0 18px;
  border-left: 4px solid var(--coral);
}

.library-stamp:nth-child(2) {
  border-color: var(--lime);
}

.library-stamp:nth-child(3) {
  border-color: var(--blue);
}

.library-stamp strong {
  display: block;
  font: 500 42px/.9 var(--serif);
  letter-spacing: -.06em;
}

.library-stamp span {
  color: var(--muted);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: .07em;
  text-transform: uppercase;
}

.section {
  padding: 52px 0;
  border-bottom: 1px solid var(--line);
}

.split-layout {
  display: grid;
  grid-template-columns: 3fr 2fr;
  gap: 24px;
  margin-top: 24px;
}

.split-layout > * {
  min-width: 0;
}

.diagram-frame {
  display: block;
  width: 100%;
  min-width: 0;
  min-height: 400px;
  aspect-ratio: 1447 / 2100;
  border: 1px solid var(--ink);
  background: var(--panel);
  overflow: hidden;
}

.step-list {
  position: sticky;
  top: 90px;
  align-self: start;
  border-top: 1px solid var(--ink);
  border-left: 1px solid var(--ink);
}

.step {
  padding: 16px;
  border-right: 1px solid var(--ink);
  border-bottom: 1px solid var(--ink);
  background: var(--panel);
}

.step:nth-child(odd) {
  background: var(--alt);
}

.step h3 {
  margin: 0;
  font: 500 22px/1 var(--serif);
}

.step h3 span {
  margin-right: 7px;
  color: var(--coral);
  font: 700 11px/1 var(--mono);
}

/* Cards and chips */
.card-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  margin-top: 22px;
  border-top: 1px solid var(--ink);
  border-left: 1px solid var(--ink);
}

.guide-card {
  display: grid;
  min-width: 0;
  border-right: 1px solid var(--ink);
  border-bottom: 1px solid var(--ink);
  background: var(--panel);
}

.card-body {
  display: flex;
  min-width: 0;
  min-height: 210px;
  flex-direction: column;
  padding: 19px;
}

.card-meta {
  display: flex;
  gap: 12px;
  align-items: center;
  justify-content: space-between;
  color: var(--muted);
  font: 700 10px/1 var(--mono);
  letter-spacing: .05em;
  text-transform: uppercase;
}

.type-tag {
  padding: 4px 6px;
  background: var(--coral);
  color: var(--ink);
  white-space: nowrap;
}

.guide-card h3 {
  margin: 17px 0 9px;
  font: 500 27px/1.02 var(--serif);
  letter-spacing: -.045em;
}

.guide-card p {
  margin: 0;
  color: var(--copy2);
  font-size: 13px;
}

.card-footer {
  margin-top: auto;
  padding-top: 22px;
}

.card-footer a,
.top-link {
  border-bottom: 1px solid currentColor;
  font: 700 11px/1 var(--mono);
  letter-spacing: .04em;
  text-decoration: none;
}

.chips,
.backlink-rows {
  display: flex;
  min-width: 0;
  flex-wrap: wrap;
  gap: 6px;
  margin: 16px 0 0;
  padding: 0;
  list-style: none;
}

.chip {
  display: inline-flex;
  min-width: 0;
  min-height: 26px;
  align-items: center;
  padding: 4px 8px;
  border: 1px solid var(--line);
  background: var(--alt);
  font: 700 10px/1 var(--mono);
  overflow-wrap: anywhere;
  text-decoration: none;
}

.chip:hover {
  background: var(--ink);
  color: var(--panel);
}

.topic-group {
  margin-top: 48px;
}

.topic-group > h2 {
  margin: 0;
}

.diagram-thumbnail {
  display: block;
  width: 100%;
  max-height: 180px;
  object-fit: contain;
  border-bottom: 1px solid var(--line);
  background: var(--visual);
}

/* Topic and solution pages */
.page-hero {
  padding: 54px 0 28px;
}

.breadcrumb {
  color: var(--muted);
  font: 700 12px/1.4 var(--mono);
}

.summary-card {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  margin-top: 34px;
  border: 1px solid var(--ink);
  background: var(--panel);
}

.summary-card div {
  min-width: 0;
  padding: 18px;
  border-right: 1px solid var(--ink);
}

.summary-card div:last-child {
  border: 0;
}

.summary-card strong {
  font: 700 11px var(--mono);
  letter-spacing: .06em;
  text-transform: uppercase;
}

.summary-card p {
  margin: 9px 0 0;
  color: var(--copy);
  font-size: 14px;
}

.content {
  max-width: 1000px;
  padding: 24px 0 56px;
}

.on-page,
.backlinks {
  padding: 18px 0;
  border-bottom: 1px solid var(--line);
}

.on-page h2,
.backlinks h2,
.original > h2 {
  margin: 0 0 12px;
  font-size: 27px;
}

.on-page ul {
  margin: 0;
  padding-left: 20px;
}

.backlink-row,
.topic-use {
  display: flex;
  min-width: 0;
  flex-wrap: wrap;
  gap: 6px;
  align-items: center;
}

.backlink-rows,
.topic-use .chips {
  flex-direction: column;
  align-items: flex-start;
}

.backlink-sections {
  color: var(--copy2);
  font: 700 11px/1.4 var(--mono);
}

.backlink-sections summary {
  cursor: pointer;
}

.backlink-sections ul {
  margin: 6px 0 0;
  padding-left: 16px;
}

.backlink-sections a {
  color: inherit;
}

.topic-use {
  margin-top: 16px;
}

.topic-use-name {
  font: 700 15px/1.2 var(--serif);
}

.topic-use .chips {
  flex-direction: row;
  margin: 0;
}

.original {
  min-width: 0;
  margin-top: 36px;
}

.original > h2 {
  padding-bottom: 15px;
  border-bottom: 1px solid var(--ink);
}

.original h1 {
  margin: 28px 0 15px;
  font-size: 38px;
}

.original h2 {
  margin-top: 32px;
}

.original h3 {
  font-size: 24px;
}

.original img,
.solution-image {
  max-width: 100%;
  height: auto;
}

.original pre {
  overflow: auto;
  padding: 14px;
  background: var(--alt);
  font-size: 13px;
}

.original table {
  display: block;
  overflow: auto;
  border-collapse: collapse;
}

.original th,
.original td {
  padding: 7px;
  border: 1px solid var(--line);
}

.page-nav {
  display: flex;
  gap: 20px;
  justify-content: space-between;
  margin-top: 40px;
  font: 700 12px var(--mono);
}

/* Gallery and footer */
.gallery-heading {
  margin-top: 50px;
}

.gallery {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 16px;
  margin-top: 22px;
}

.gallery-card {
  min-width: 0;
  margin: 0;
  border: 1px solid var(--line);
  background: var(--panel);
}

.gallery-card img {
  display: block;
  width: 100%;
  max-height: 220px;
  object-fit: contain;
  background: var(--visual);
}

.gallery-card p {
  margin: 0;
  padding: 10px;
  overflow-wrap: anywhere;
  font-size: 12px;
}

.footer {
  display: flex;
  gap: 24px;
  justify-content: space-between;
  padding: 25px 0 50px;
  color: var(--muted);
  font-size: 12px;
}

.footer p {
  margin: 0;
}

/* Responsive layout */
@media (max-width: 1050px) {
  .card-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (max-width: 900px) {
  .split-layout {
    grid-template-columns: minmax(0, 1fr);
  }

  .step-list {
    position: static;
  }

  .summary-card {
    grid-template-columns: minmax(0, 1fr);
  }

  .summary-card div {
    border-right: 0;
    border-bottom: 1px solid var(--ink);
  }

  .gallery {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (max-width: 680px) {
  .shell {
    width: min(1460px, calc(100% - 32px));
  }

  .tabs {
    width: 100%;
    overflow-x: auto;
  }

  .tab {
    padding: 10px 10px 12px;
  }

  .card-grid,
  .gallery {
    grid-template-columns: minmax(0, 1fr);
  }

  .footer {
    flex-direction: column;
  }
}

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

/* Interactive diagram wrappers */
:root {
  --topbar: 72px;
  --intro: 0px;
  --footer: 0px;
}

.overview-intro {
  display: flex;
  min-width: 0;
  min-height: 0;
  align-items: center;
  justify-content: space-between;
  gap: 22px;
  padding: 13px 0;
  border-bottom: 1px solid var(--ink);
}

.overview-intro h1 {
  max-width: none;
  font: 500 clamp(22px, 2.5vw, 35px)/1 var(--serif);
  letter-spacing: -.045em;
}

.inline-stats {
  display: flex;
  flex: none;
  flex-wrap: wrap;
  gap: 13px;
  color: var(--muted);
  font: 700 10px/1 var(--mono);
  letter-spacing: .06em;
  text-transform: uppercase;
}

.inline-stats strong {
  color: var(--ink);
  font-size: 16px;
}

.diagram-page .shell,
.overview-diagram .shell {
  height: 100%;
}

.diagram-split {
  display: flex;
  min-width: 0;
  gap: clamp(14px, 2vw, 28px);
  margin: 0;
}

.diagram-frame-wrap {
  min-width: 0;
  overflow: hidden;
  border: 1px solid var(--ink);
  background: var(--panel);
}

.diagram-frame-wrap .diagram-frame {
  display: block;
  width: 100%;
  min-width: 0;
  min-height: 0;
  height: 100%;
  aspect-ratio: auto;
  border: 0;
}

.diagram-side {
  min-width: 0;
  padding: 16px;
  border: 1px solid var(--ink);
  background: var(--panel);
}

.diagram-side .eyebrow {
  margin-bottom: 8px;
}

.diagram-side h1 {
  max-width: none;
  font: 500 clamp(26px, 2.4vw, 42px)/.96 var(--serif);
  letter-spacing: -.05em;
}

.diagram-one-line,
.diagram-howto {
  margin: 10px 0 0;
  color: var(--copy);
  font-size: 13px;
  line-height: 1.35;
}

.diagram-howto {
  color: var(--muted);
  font-size: 12px;
}

.diagram-side .step-list {
  position: static;
  display: grid;
  max-height: none;
  margin-top: 14px;
  border: 0;
}

.diagram-side .step {
  display: flex;
  min-width: 0;
  align-items: baseline;
  gap: 8px;
  padding: 8px 0;
  border: 0;
  border-top: 1px solid var(--line);
  background: transparent;
}

.diagram-side .step:nth-child(odd) {
  background: transparent;
}

.step-name {
  flex: 0 1 auto;
  color: inherit;
  font: 500 17px/1.08 var(--serif);
  text-decoration: none;
}

.step-name span {
  margin-right: 5px;
  color: var(--coral);
  font: 700 10px/1 var(--mono);
}

.diagram-side .chips {
  flex: 1 1 140px;
  gap: 4px;
  margin: 0;
}

.diagram-side .chip {
  min-height: 20px;
  padding: 3px 5px;
  font-size: 9px;
}

.walkthrough-link,
.diagram-page-link a {
  display: inline-block;
  margin-top: 12px;
  font: 700 11px/1.2 var(--mono);
}

.diagram-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 5px;
  margin-top: 16px;
  color: var(--muted);
  font: 700 10px/1.25 var(--mono);
}

.diagram-nav a { color: var(--ink); }

.diagram-inline {
  width: 100%;
  min-height: 0;
  aspect-ratio: var(--ar);
}

.diagram-page-link { margin: 10px 0 0; }

@media (min-width: 901px) {
  body.diagram-page-body,
  body.landing-page.landing-overview {
    height: 100vh;
    overflow: hidden;
  }

  body.diagram-page-body .footer,
  body.landing-page.landing-overview .footer {
    min-height: 0;
    padding: 5px 0;
    font-size: 9px;
    line-height: 1.2;
  }

  body.diagram-page-body .footer p,
  body.landing-page.landing-overview .footer p {
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
  }

  .diagram-page,
  .overview-diagram {
    height: calc(100vh - var(--topbar) - var(--intro) - var(--footer));
  }

  .diagram-split {
    height: 100%;
    align-items: stretch;
  }

  /* The iframe fills the split; its internal grid gives the measured controls their own row. */
  .diagram-split > .diagram-frame-wrap {
    flex: 0 1 auto;
    width: auto;
    max-width: 65%;
    height: 100%;
    aspect-ratio: var(--ar);
    align-self: stretch;
  }

  .diagram-side {
    flex: 1 1 280px;
    height: 100%;
    overflow: auto;
  }
}

@media (max-width: 900px) {
  .overview-intro {
    align-items: flex-start;
    flex-direction: column;
  }

  .diagram-split {
    flex-direction: column;
    margin-top: 18px;
  }

  .diagram-split > .diagram-frame-wrap,
  .diagram-inline {
    width: 100%;
    height: auto;
    aspect-ratio: var(--ar);
  }

  .diagram-frame-wrap .diagram-frame {
    height: 100%;
  }

  .diagram-side { width: 100%; }
}