:root {
  color-scheme: light;
  --ink: #1c3038;
  --muted: #607078;
  --line: #cdd7da;
  --paper: #f8faf9;
  --surface: #e8eff1;
  --teal: #0a8184;
  --teal-dark: #086b6e;
  --orange: #a85c0d;
  font-family: Inter, "Segoe UI", Arial, sans-serif;
  font-synthesis: none;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  overflow-x: clip;
  background: var(--paper);
  color: var(--ink);
  letter-spacing: 0;
}

a {
  color: inherit;
}

.site-header {
  min-height: 68px;
  position: sticky;
  z-index: 20;
  top: 0;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  padding: 10px max(24px, calc((100vw - 1120px) / 2));
  border-bottom: 1px solid rgba(28, 48, 56, 0.14);
  background: rgba(248, 250, 249, 0.94);
  backdrop-filter: blur(14px);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
}

.brand > svg {
  width: 27px;
  height: 27px;
  color: var(--teal);
  stroke-width: 1.7;
}

.brand span {
  display: grid;
  gap: 1px;
}

.brand strong {
  font-size: 16px;
}

.brand small {
  color: var(--muted);
  font-size: 10px;
}

.site-header nav {
  display: flex;
  align-items: center;
  gap: 20px;
}

.site-header nav a {
  color: #43565e;
  font-size: 13px;
  font-weight: 650;
  text-decoration: none;
}

.site-header nav a:hover {
  color: var(--teal-dark);
}

.site-header .open-model,
.primary-action,
.closing-action > a {
  display: inline-flex;
  min-height: 42px;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 0 16px;
  border: 1px solid var(--teal-dark);
  border-radius: 5px;
  background: var(--teal);
  color: #fff;
  font-weight: 700;
  text-decoration: none;
}

.site-header .open-model svg,
.primary-action svg,
.closing-action > a svg,
.path-list a svg {
  width: 16px;
  height: 16px;
}

main {
  width: min(1120px, calc(100% - 48px));
  margin: 0 auto;
}

.guide-intro {
  max-width: 830px;
  padding: 84px 0 42px;
}

.eyebrow {
  margin: 0 0 12px;
  color: var(--teal-dark);
  font-size: 11px;
  font-weight: 800;
  text-transform: uppercase;
}

h1,
h2,
h3,
p {
  letter-spacing: 0;
}

h1 {
  max-width: 780px;
  margin: 0;
  font-size: 68px;
  line-height: 1.02;
  font-weight: 760;
}

.lede {
  max-width: 760px;
  margin: 24px 0 0;
  color: #455b64;
  font-size: 19px;
  line-height: 1.65;
}

.intro-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 30px;
}

.secondary-action {
  display: inline-flex;
  min-height: 42px;
  align-items: center;
  padding: 0 16px;
  border: 1px solid #aebcc1;
  border-radius: 5px;
  background: #fff;
  color: #334950;
  font-size: 13px;
  font-weight: 700;
  text-decoration: none;
}

.primary-action:hover,
.closing-action > a:hover,
.site-header .open-model:hover {
  background: var(--teal-dark);
}

.secondary-action:hover {
  border-color: #7e9198;
  background: #f5f8f8;
}

.model-figure {
  margin: 0 0 90px;
}

.model-figure img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 16 / 9;
  object-fit: cover;
  border: 1px solid #bac8cc;
  border-radius: 6px;
}

.model-figure figcaption {
  max-width: 820px;
  margin-top: 13px;
  color: var(--muted);
  font-size: 12px;
  line-height: 1.55;
}

.learning-paths,
.study-method,
.model-basis,
.references,
.reference-tools {
  padding: 76px 0;
  border-top: 1px solid var(--line);
}

.section-heading {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(280px, 0.62fr);
  column-gap: 60px;
  align-items: end;
  margin-bottom: 42px;
}

.section-heading .eyebrow {
  grid-column: 1 / -1;
}

.section-heading h2 {
  margin: 0;
  font-size: 44px;
  line-height: 1.08;
}

.section-heading > p:last-child {
  margin: 0 0 4px;
  color: var(--muted);
  font-size: 15px;
  line-height: 1.6;
}

.path-list {
  margin: 0;
  padding: 0;
  list-style: none;
  border-top: 1px solid var(--line);
}

.path-list li {
  display: grid;
  grid-template-columns: 58px minmax(0, 1fr) 170px;
  gap: 22px;
  align-items: start;
  padding: 29px 0;
  border-bottom: 1px solid var(--line);
}

.path-number {
  color: var(--orange);
  font-family: "Cascadia Mono", Consolas, monospace;
  font-size: 12px;
  font-weight: 750;
}

.path-list h3 {
  margin: -4px 0 8px;
  font-size: 20px;
}

.path-list p {
  max-width: 670px;
  margin: 0;
  color: #52656d;
  font-size: 14px;
  line-height: 1.65;
}

.path-list a {
  display: inline-flex;
  align-items: center;
  justify-content: flex-end;
  gap: 8px;
  color: var(--teal-dark);
  font-size: 13px;
  font-weight: 750;
  text-decoration: none;
}

.path-list a:hover {
  text-decoration: underline;
  text-underline-offset: 4px;
}

.path-actions {
  display: grid;
  gap: 9px;
  justify-items: end;
}

.path-actions .path-model {
  color: var(--muted);
  font-size: 11px;
  font-weight: 650;
}

.instructor-strip {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  gap: 42px;
  align-items: center;
  padding: 44px 0;
  border-top: 1px solid var(--line);
}

.instructor-strip h2 {
  margin: 0;
  font-size: 32px;
  line-height: 1.16;
}

.instructor-strip p:not(.eyebrow) {
  max-width: 720px;
  margin: 13px 0 0;
  color: var(--muted);
  font-size: 14px;
  line-height: 1.65;
}

.instructor-strip > a {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  color: var(--teal-dark);
  font-size: 13px;
  font-weight: 750;
  text-decoration: none;
}

.instructor-strip > a:hover {
  text-decoration: underline;
  text-underline-offset: 4px;
}

.instructor-strip svg {
  width: 16px;
  height: 16px;
}

.reference-tool-list {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.reference-tool-list article {
  min-width: 0;
  padding: 30px 32px 32px 0;
}

.reference-tool-list article + article {
  padding-right: 0;
  padding-left: 32px;
  border-left: 1px solid var(--line);
}

.reference-tool-list h3 {
  margin: 0 0 10px;
  font-size: 21px;
}

.reference-tool-list p {
  margin: 0 0 18px;
  color: var(--muted);
  font-size: 14px;
  line-height: 1.65;
}

.reference-tool-list a {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  color: var(--teal-dark);
  font-size: 13px;
  font-weight: 750;
  text-decoration: none;
}

.reference-tool-list a:hover {
  text-decoration: underline;
  text-underline-offset: 4px;
}

.reference-tool-list svg {
  width: 16px;
  height: 16px;
}

.method-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.method-grid article {
  min-width: 0;
  padding: 26px 22px 28px;
  border-right: 1px solid var(--line);
}

.method-grid article:first-child {
  padding-left: 0;
}

.method-grid article:last-child {
  padding-right: 0;
  border-right: 0;
}

.method-grid span {
  display: block;
  margin-bottom: 38px;
  color: var(--orange);
  font-family: "Cascadia Mono", Consolas, monospace;
  font-size: 12px;
  font-weight: 750;
}

.method-grid h3 {
  margin: 0 0 9px;
  font-size: 17px;
}

.method-grid p {
  margin: 0;
  color: var(--muted);
  font-size: 13px;
  line-height: 1.6;
}

.model-basis {
  margin-right: 0;
  margin-left: 0;
  padding-right: 0;
  padding-left: 0;
  background: var(--surface);
  box-shadow: 0 0 0 100vmax var(--surface);
  clip-path: inset(0 -100vmax);
}

.basis-list {
  margin: 0;
  border-top: 1px solid #bcc9cd;
}

.basis-list > div {
  display: grid;
  grid-template-columns: 220px minmax(0, 1fr);
  gap: 34px;
  padding: 23px 0;
  border-bottom: 1px solid #bcc9cd;
}

.basis-list dt {
  font-size: 14px;
  font-weight: 750;
}

.basis-list dd {
  max-width: 740px;
  margin: 0;
  color: #4f6269;
  font-size: 14px;
  line-height: 1.65;
}

.references ul {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 0 36px;
  margin: 0;
  padding: 0;
  list-style: none;
  border-top: 1px solid var(--line);
}

.references li {
  padding: 18px 0;
  border-bottom: 1px solid var(--line);
}

.references a {
  color: #31545c;
  font-size: 14px;
  font-weight: 650;
  text-decoration: none;
}

.references a:hover {
  color: var(--teal-dark);
  text-decoration: underline;
  text-underline-offset: 4px;
}

.closing-action {
  min-height: 180px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 32px;
  margin-bottom: 64px;
  padding: 38px 42px;
  border-radius: 6px;
  background: #243940;
  color: #f4f8f8;
}

.closing-action .eyebrow {
  color: #88d2d3;
}

.closing-action h2 {
  max-width: 620px;
  margin: 0;
  font-size: 36px;
  line-height: 1.15;
}

.closing-action > a {
  flex: 0 0 auto;
}

footer {
  display: flex;
  justify-content: space-between;
  gap: 20px;
  padding: 28px max(24px, calc((100vw - 1120px) / 2));
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 12px;
}

footer a {
  color: #31545c;
  font-weight: 650;
  text-decoration: none;
}

footer a:hover {
  color: var(--teal-dark);
  text-decoration: underline;
  text-underline-offset: 3px;
}

.footer-links {
  display: flex;
  flex-wrap: wrap;
  gap: 12px 20px;
}

@media (max-width: 820px) {
  .site-header {
    padding: 10px 16px;
  }

  .site-header nav > a:not(.open-model) {
    display: none;
  }

  .site-header .open-model {
    min-height: 42px;
    padding: 0 12px;
  }

  main {
    width: min(100% - 32px, 680px);
  }

  .guide-intro {
    padding: 58px 0 32px;
  }

  h1 {
    font-size: 52px;
  }

  .section-heading h2 {
    font-size: 38px;
  }

  .lede {
    font-size: 17px;
  }

  .model-figure {
    margin-bottom: 62px;
  }

    .learning-paths,
    .study-method,
    .model-basis,
    .references,
    .reference-tools {
      padding-top: 54px;
      padding-bottom: 54px;
    }

  .section-heading {
    display: block;
    margin-bottom: 30px;
  }

  .section-heading > p:last-child {
    margin-top: 14px;
  }

  .path-list li {
    grid-template-columns: 42px minmax(0, 1fr);
    gap: 14px;
  }

  .path-list a {
    grid-column: 2;
    justify-content: flex-start;
  }

  .path-actions {
    grid-column: 2;
    justify-items: start;
  }

  .instructor-strip {
    grid-template-columns: 1fr;
    gap: 20px;
    padding: 36px 0;
  }

  .reference-tool-list {
    grid-template-columns: 1fr;
  }

  .reference-tool-list article,
  .reference-tool-list article + article {
    padding: 24px 0;
    border-left: 0;
  }

  .reference-tool-list article + article {
    border-top: 1px solid var(--line);
  }

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

  .method-grid article,
  .method-grid article:first-child,
  .method-grid article:last-child {
    padding: 22px 18px 24px;
    border-right: 1px solid var(--line);
    border-bottom: 1px solid var(--line);
  }

  .method-grid article:nth-child(2n) {
    border-right: 0;
  }

  .method-grid article:nth-last-child(-n + 2) {
    border-bottom: 0;
  }

  .method-grid span {
    margin-bottom: 24px;
  }

  .basis-list > div {
    grid-template-columns: 1fr;
    gap: 8px;
  }

  .references ul {
    grid-template-columns: 1fr;
  }

  .closing-action {
    display: grid;
    margin-bottom: 38px;
    padding: 30px 24px;
  }

  .closing-action > a {
    justify-self: start;
  }

  .closing-action h2 {
    font-size: 32px;
  }

  footer {
    display: grid;
    padding: 22px 16px;
  }
}

@media (max-width: 480px) {
  .brand small {
    display: none;
  }

  .site-header .open-model {
    width: 42px;
    padding: 0;
    font-size: 0;
  }

  .site-header .open-model svg {
    width: 18px;
    height: 18px;
  }

  .intro-actions {
    display: grid;
  }

  h1 {
    font-size: 40px;
  }

  .section-heading h2 {
    font-size: 32px;
  }

  .closing-action h2 {
    font-size: 28px;
  }

  .primary-action,
  .secondary-action {
    width: 100%;
  }

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

  .method-grid article,
  .method-grid article:first-child,
  .method-grid article:last-child,
  .method-grid article:nth-child(2n),
  .method-grid article:nth-last-child(-n + 2) {
    padding: 22px 0 24px;
    border-right: 0;
    border-bottom: 1px solid var(--line);
  }

  .method-grid article:last-child {
    border-bottom: 0;
  }
}

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