@font-face { font-family: "Ubuntu Sans"; src: url("/assets/fonts/UbuntuSans-Bold.ttf") format("truetype"); font-display: swap; font-style: normal; font-weight: 700 800; }
@font-face { font-family: Charter; src: url("/assets/fonts/Charter-Regular.ttf") format("truetype"); font-display: swap; font-style: normal; font-weight: 400; }

:root { color-scheme: light; --cream: #f5f0df; --paper: #fffdf6; --ink: #141414; --coral: #f16b4a; --muted: #655f54; --line: rgba(20,20,20,.2); --sans: "Ubuntu Sans", ui-sans-serif, system-ui, sans-serif; --serif: Charter, Georgia, serif; }
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { margin: 0; background: var(--cream); color: var(--ink); font-family: var(--serif); font-size: 18px; line-height: 1.55; }
img { display: block; max-width: 100%; }
a { color: inherit; }
h1, h2, h3, p { margin-top: 0; }

.site-header, main, footer { width: min(100% - 40px, 1280px); margin-inline: auto; }
.site-header { display: flex; align-items: center; justify-content: space-between; padding: 18px 0; border-bottom: 1px solid var(--line); }
.brand { display: inline-flex; align-items: center; gap: 9px; font-family: var(--sans); font-size: 1.28rem; letter-spacing: -.045em; line-height: 1; text-decoration: none; }
.brand img { width: 48px; height: 48px; object-fit: contain; }
.brand strong, .brand em { font: inherit; font-weight: 800; }
.brand em, .footer-brand span { color: var(--coral); }
nav { display: flex; gap: 28px; font-family: var(--sans); font-size: .72rem; font-weight: 800; letter-spacing: .12em; text-transform: uppercase; }
nav a { text-decoration: none; }
nav a:hover, nav a:focus-visible { color: var(--coral); }

.intro { display: grid; grid-template-columns: minmax(0,1.1fr) minmax(280px,.55fr); gap: 70px; align-items: center; min-height: 430px; padding: 46px 0 52px; }
.eyebrow { margin: 0 0 15px; color: var(--coral); font-family: var(--sans); font-size: .7rem; font-weight: 800; letter-spacing: .17em; text-transform: uppercase; }
h1 { margin-bottom: 24px; font-family: var(--sans); font-size: clamp(3.4rem,6.7vw,6rem); font-weight: 800; letter-spacing: -.065em; line-height: .92; }
.intro-copy { max-width: 37rem; margin-bottom: 24px; color: var(--muted); font-size: 1.16rem; }
.text-link, .amazon-link { font-family: var(--sans); font-size: .78rem; font-weight: 800; letter-spacing: .045em; text-underline-offset: 5px; text-transform: uppercase; }
.text-link span { color: var(--coral); font-size: 1rem; }
.intro-mark { position: relative; display: grid; place-items: center; justify-self: end; width: min(100%,360px); aspect-ratio: 1; border-radius: 50%; background: var(--coral); }
.intro-mark::before { position: absolute; inset: -32px 22px 22px -34px; border: 2px solid rgba(20,20,20,.16); background: url("/assets/grid-medium.svg") center / cover; content: ""; transform: rotate(-5deg); }
.intro-mark img { position: relative; z-index: 1; width: 118%; max-width: none; filter: drop-shadow(0 18px 18px rgba(20,20,20,.12)); }

.books-section { padding: 90px 0 115px; border-top: 1px solid var(--line); }
.section-heading { margin-bottom: 48px; text-align: center; }
h2 { margin-bottom: 0; font-family: var(--sans); font-size: clamp(2.7rem,5vw,4.7rem); font-weight: 800; letter-spacing: -.055em; line-height: .98; }
.catalog-intro { max-width: 38rem; margin: 20px auto 0; color: var(--muted); font-size: .92rem; }
.book-grid { display: grid; grid-template-columns: repeat(4,minmax(0,1fr)); gap: clamp(22px,3vw,42px); }
.book-card { min-width: 0; text-align: center; }
.real-cover { width: 100%; height: auto; margin-bottom: 24px; box-shadow: 0 14px 26px rgba(20,20,20,.1); }
.book-card h3 { margin-bottom: 4px; font-family: var(--sans); font-size: 1.45rem; font-weight: 800; letter-spacing: -.035em; line-height: 1.1; }
.book-card p { min-height: 3.1em; margin: 0 auto 14px; color: var(--muted); font-size: .92rem; }
.availability { color: var(--coral); font-family: var(--sans); font-size: .78rem; font-weight: 800; letter-spacing: .045em; text-transform: uppercase; }
a.availability { text-underline-offset: 5px; }

.about-section { display: grid; grid-template-columns: .55fr 1fr; gap: clamp(50px,9vw,120px); align-items: center; padding: 95px 0 110px; border-top: 1px solid var(--line); }
.about-zebra { display: grid; place-items: center; aspect-ratio: 1; border: 2px solid var(--ink); background: var(--paper); }
.about-zebra img { width: 84%; }
.about-copy h2 { max-width: 12ch; margin-bottom: 24px; }
.about-copy > p:last-child { max-width: 37rem; margin-bottom: 0; color: var(--muted); font-size: 1.08rem; }

.difficulty-section { padding: 90px 0 115px; border-top: 1px solid var(--line); }
.difficulty-grid { display: grid; grid-template-columns: repeat(3,minmax(0,1fr)); gap: clamp(28px,5vw,64px); }
.difficulty-card { text-align: center; }
.grid-example { display: grid; place-items: center; aspect-ratio: 1; margin-bottom: 25px; padding: clamp(24px,3vw,44px); border: 1px solid var(--line); background: var(--paper); }
.grid-example img { width: 100%; height: 100%; object-fit: contain; }
.difficulty-card h3 { margin-bottom: 7px; font-family: var(--sans); font-size: 1.55rem; font-weight: 800; letter-spacing: -.035em; }
.difficulty-card p { max-width: 19rem; margin: 0 auto; color: var(--muted); font-size: .94rem; }

footer { display: grid; grid-template-columns: 1fr auto auto; gap: 30px; align-items: center; padding: 32px 0 40px; border-top: 1px solid var(--line); font-family: var(--sans); font-size: .72rem; }
footer p { margin-bottom: 0; }
.footer-brand { font-size: 1rem; font-weight: 800; letter-spacing: -.04em; text-decoration: none; }

.article-page, .download-page { width: min(100%, 1080px); margin-inline: auto; padding: 76px 0 115px; }
.article-hero { max-width: 820px; margin: 0 auto 60px; text-align: center; }
.article-hero h1 { margin-bottom: 24px; font-size: clamp(3.2rem, 7vw, 6.1rem); }
.article-lede { max-width: 42rem; margin: 0 auto; color: var(--muted); font-size: 1.18rem; }
.article-layout { display: grid; grid-template-columns: minmax(0, 1.45fr) minmax(280px, .7fr); gap: clamp(42px, 8vw, 110px); align-items: start; }
.article-copy { max-width: 42rem; }
.article-copy h2, .source-card h2 { margin: 0 0 17px; font-family: var(--sans); font-size: clamp(1.85rem, 3vw, 2.75rem); font-weight: 800; letter-spacing: -.05em; line-height: 1; }
.article-copy h2:not(:first-child) { margin-top: 48px; }
.article-copy p { color: var(--muted); }
.source-card { padding: 31px; border: 1px solid var(--ink); background: var(--paper); }
.source-card .eyebrow { margin-bottom: 12px; }
.source-card ul { display: grid; gap: 20px; margin: 28px 0 0; padding: 0; list-style: none; }
.source-card li { color: var(--muted); font-size: .9rem; line-height: 1.4; }
.source-card li a { display: inline-block; color: var(--ink); font-family: var(--sans); font-size: .85rem; font-weight: 800; text-underline-offset: 4px; }
.source-card li span { display: block; margin-top: 3px; }
.download-page { width: min(100%, 1120px); }
.download-callout { display: flex; align-items: center; gap: 24px; max-width: 770px; margin: 0 auto 42px; padding: 20px 26px; border: 1px solid var(--line); background: var(--paper); }
.download-callout img { width: 84px; height: 84px; object-fit: contain; }
.download-callout p { margin: 0; color: var(--muted); font-size: .92rem; }
.download-callout strong { color: var(--ink); font-family: var(--sans); }
.table-wrap { overflow-x: auto; border: 1px solid var(--ink); background: var(--paper); }
table { width: 100%; border-collapse: collapse; text-align: left; }
caption { padding: 22px 26px; border-bottom: 1px solid var(--ink); font-family: var(--sans); font-size: 1.25rem; font-weight: 800; letter-spacing: -.03em; text-align: left; }
th { padding: 14px 26px; border-bottom: 1px solid var(--line); color: var(--muted); font-family: var(--sans); font-size: .67rem; font-weight: 800; letter-spacing: .13em; text-transform: uppercase; }
td { padding: 19px 26px; border-bottom: 1px solid var(--line); vertical-align: middle; }
tbody tr:last-child td { border-bottom: 0; }
td:first-child { font-family: var(--sans); font-size: 1rem; font-weight: 800; }
td:nth-child(2) { min-width: 215px; color: var(--muted); font-size: .88rem; }
.difficulty-tag { display: inline-block; min-width: 74px; padding: 4px 8px; border: 1px solid currentColor; font-family: var(--sans); font-size: .66rem; font-weight: 800; letter-spacing: .1em; text-align: center; text-transform: uppercase; }
.difficulty-tag.easy { color: #537a44; }
.difficulty-tag.medium { color: #9a6919; }
.difficulty-tag.hard { color: #a74535; }
.download-link { color: var(--ink); font-family: var(--sans); font-size: .74rem; font-weight: 800; letter-spacing: .06em; text-decoration-thickness: 1px; text-underline-offset: 5px; text-transform: uppercase; white-space: nowrap; }
.download-link:hover, .download-link:focus-visible { color: var(--coral); }

@media (max-width: 800px) {
  .intro { grid-template-columns: 1fr; gap: 35px; padding-block: 52px 60px; }
  .intro-mark { justify-self: center; width: min(76vw,390px); }
  .book-grid { grid-template-columns: repeat(2,minmax(0,1fr)); }
  .about-section { grid-template-columns: .7fr 1fr; gap: 35px; }
  .difficulty-grid { grid-template-columns: repeat(3,minmax(0,1fr)); gap: 22px; }
  .article-layout { grid-template-columns: 1fr; gap: 42px; }
  .article-copy { max-width: 48rem; }
  .source-card { max-width: 48rem; }
  footer { grid-template-columns: 1fr; gap: 5px; }
}
@media (max-width: 540px) {
  body { font-size: 16px; }
  .site-header, main, footer { width: min(100% - 28px,1160px); }
  .brand img { width: 40px; height: 40px; }
  .brand { font-size: 1rem; }
  nav { gap: 11px; font-size: .55rem; letter-spacing: .08em; }
  .intro { min-height: 0; padding: 46px 0 54px; }
  h1 { font-size: clamp(3.25rem,16vw,4.8rem); }
  .article-page, .download-page { padding: 54px 0 80px; }
  .article-hero { margin-bottom: 42px; text-align: left; }
  .article-hero h1 { font-size: clamp(2.8rem, 14vw, 4.25rem); }
  .article-lede { margin: 0; }
  .download-callout { align-items: flex-start; padding: 18px; }
  .download-callout img { width: 58px; height: 58px; }
  caption, th, td { padding-inline: 18px; }
  .table-wrap { overflow: visible; border: 0; background: transparent; }
  .table-wrap caption { display: none; }
  .table-wrap thead { position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; }
  .table-wrap table, .table-wrap tbody { display: block; }
  .table-wrap tbody { display: grid; gap: 14px; }
  .table-wrap tr { display: block; padding: 8px 18px; border: 1px solid var(--ink); background: var(--paper); }
  .table-wrap td { display: grid; grid-template-columns: 100px minmax(0, 1fr); gap: 12px; min-width: 0; padding: 11px 0; border-bottom: 1px solid var(--line); }
  .table-wrap td:last-child { border-bottom: 0; }
  .table-wrap td::before { align-self: center; color: var(--muted); font-family: var(--sans); font-size: .61rem; font-weight: 800; letter-spacing: .11em; text-transform: uppercase; content: attr(data-label); }
  .table-wrap td:nth-child(2) { min-width: 0; }
  .book-grid { grid-template-columns: 1fr; gap: 55px; }
  .book-card { width: min(100%,340px); margin-inline: auto; }

  .books-section { padding: 74px 0 90px; }
  .section-heading { margin-bottom: 38px; }
  .about-section { grid-template-columns: 1fr; padding: 78px 0 90px; }
  .about-zebra { width: min(72vw,300px); }
  .difficulty-section { padding: 74px 0 90px; }
  .difficulty-grid { grid-template-columns: 1fr; gap: 48px; }
  .difficulty-card { width: min(100%,340px); margin-inline: auto; }
}
@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } }