:root {
  --ink: #0e1b2c;
  --ink-2: #1b3a5c;
  --paper: #f4f7fa;
  --paper-2: #e7eef6;
  --white: #ffffff;
  --shaft: #8dbdf0;
  --blue: #1f6fd1;
  --blue-dark: #164f97;
  --slate: #465468;
  --rule: #c9d4e0;
  --todo: #ffe08a;
  --sans: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --serif: "Iowan Old Style", "Palatino Linotype", Palatino, Georgia, "Times New Roman", serif;
}
*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  font-family: var(--serif);
  font-size: 1.125rem;
  line-height: 1.7;
  color: var(--ink);
  background: var(--paper);
}
h1, h2, h3 { font-family: var(--sans); font-weight: 800; line-height: 1.12; letter-spacing: -0.02em; margin: 0 0 .6em; }
h1 { font-size: clamp(2rem, 5vw, 3.1rem); }
h2 { font-size: clamp(1.4rem, 3vw, 1.8rem); margin-top: 2.2em; }
p { margin: 0 0 1.1em; }
a { color: var(--blue-dark); text-underline-offset: 3px; }
a:hover { color: var(--ink); }
:focus-visible { outline: 3px solid #ffbf47; outline-offset: 3px; }
.skip { position: absolute; left: -999px; top: 0; background: var(--white); color: var(--ink); padding: .6rem 1rem; z-index: 10; }
.skip:focus { left: 0; }
.wrap { width: 100%; max-width: 68rem; margin: 0 auto; padding: 0 1.25rem; }
.narrow { max-width: 44rem; }

/* header */
.site-header { background: var(--ink); color: var(--white); }
.header-row { display: flex; flex-wrap: wrap; align-items: center; justify-content: space-between; gap: .5rem 2rem; padding-top: 1rem; padding-bottom: 1rem; }
.brand { font-family: var(--sans); font-weight: 800; font-size: 1.25rem; letter-spacing: -0.01em; color: var(--white); text-decoration: none; }
.site-header nav { display: flex; flex-wrap: wrap; gap: .25rem 1.5rem; font-family: var(--sans); font-size: 1rem; }
.site-header nav a { color: #d6e4f5; text-decoration: none; padding: .35rem 0; border-bottom: 2px solid transparent; }
.site-header nav a:hover { color: var(--white); border-bottom-color: var(--shaft); }
.site-header nav a[aria-current="page"] { color: var(--white); border-bottom-color: var(--shaft); }

/* hero: a slanted shaft of light behind the cover, echoing the cover art */
.hero { position: relative; overflow: hidden; background: var(--ink); color: var(--white); }
.hero-grid { display: grid; gap: 2.5rem; padding-top: 3.5rem; padding-bottom: 3.5rem; align-items: center; }
.hero-text { position: relative; z-index: 1; }
.hero h1 { color: var(--white); max-width: 15em; }
.hero .lead { font-size: 1.25rem; color: #dbe7f5; max-width: 34em; }
.byline { color: #b9cce3; font-size: 1rem; margin-top: 1.5rem; }
.hero-art { position: static; display: flex; justify-content: center; }
.hero-art::before, .hero-art::after { content: ""; position: absolute; pointer-events: none; }
.hero-art::before { top: 0; bottom: 0; right: 0; width: 50%; background: var(--ink-2); clip-path: polygon(30% 0, 100% 0, 100% 100%, 0 100%); }
.hero-art::after { top: 0; bottom: 0; right: 0; width: 50%; background: var(--shaft); clip-path: polygon(38% 0, 46% 0, 16% 100%, 8% 100%); }
.hero-art .cover { position: relative; z-index: 1; width: min(320px, 100%); height: auto; box-shadow: 0 18px 40px rgba(0,0,0,.45); }
@media (min-width: 820px) {
  .hero-grid { grid-template-columns: 1.15fr .85fr; }
}
@media (max-width: 819px) {
  .hero-art { position: relative; padding: 2.5rem 0; margin: 0 -1.25rem; }
  .hero-art::before { width: 100%; clip-path: polygon(0 12%, 100% 0, 100% 100%, 0 100%); }
  .hero-art::after { width: 100%; clip-path: polygon(0 12%, 100% 0, 100% 5%, 0 17%); }
  .hero-grid { padding-bottom: 0; }
  .hero-art .cover { width: min(240px, 60%); }
}

/* buttons */
.btns { display: flex; flex-wrap: wrap; gap: .75rem; margin: 1.75rem 0 0; }
.btn { display: inline-block; padding: .8rem 1.3rem; font-family: var(--sans); font-weight: 700; font-size: 1rem; line-height: 1.2; text-decoration: none; border-radius: 4px; border: 2px solid transparent; }
.btn-primary { background: var(--blue); color: var(--white); border-color: var(--blue); }
.btn-primary:hover { background: var(--blue-dark); border-color: var(--blue-dark); color: var(--white); }
.btn-ghost { background: transparent; color: var(--white); border-color: #7f9bbd; }
.btn-ghost:hover { border-color: var(--white); color: var(--white); }

/* sections */
.block { padding: 3.5rem 0; }
.block-alt { background: var(--paper-2); }
.block h2:first-child { margin-top: 0; }
.split { display: grid; gap: 2.5rem; }
@media (min-width: 820px) { .split { grid-template-columns: 1fr 1fr; gap: 4rem; } }
ul.plain { padding-left: 1.2rem; }
ul.plain li, .page li { margin-bottom: .45em; }
.note { border-left: 4px solid var(--blue); padding: .2rem 0 .2rem 1.1rem; color: var(--slate); font-size: 1rem; margin: 2rem 0; }

/* inner pages */
.page { max-width: 46rem; padding-top: 3rem; padding-bottom: 4rem; }
.page .lead { font-size: 1.25rem; color: var(--slate); }
.book-head { display: grid; gap: 2rem; margin-bottom: 1rem; }
@media (min-width: 720px) { .book-head { grid-template-columns: 14rem 1fr; gap: 2.5rem; align-items: start; } }
.book-cover .cover { width: 100%; max-width: 14rem; height: auto; box-shadow: 0 10px 28px rgba(14,27,44,.3); }
.subtitle { font-family: var(--sans); font-weight: 600; font-size: 1.15rem; color: var(--slate); }
.facts { display: grid; grid-template-columns: max-content 1fr; gap: .25rem 1.25rem; margin: 1.75rem 0 0; font-size: 1rem; }
.facts dt { font-family: var(--sans); font-weight: 700; }
.facts dd { margin: 0; }
.btn-on-light.btn-primary { color: var(--white); }
details { border-top: 1px solid var(--rule); padding: .9rem 0; }
details:last-of-type { border-bottom: 1px solid var(--rule); }
summary { font-family: var(--sans); font-weight: 700; cursor: pointer; }
details p { margin: .8rem 0 0; }
.sample h2 { margin-top: 3rem; padding-top: 1.5rem; border-top: 1px solid var(--rule); }
.sample h2:first-of-type { border-top: 0; padding-top: 0; }
.sample h3 { font-size: 1.15rem; margin-top: 1.9rem; margin-bottom: .4em; }
.sample .source { font-family: var(--sans); font-size: .95rem; color: var(--slate); margin-top: -.3rem; }
.sample ul, .sample ol { padding-left: 1.4rem; margin: 0 0 1.1em; }
.sample li { margin-bottom: .3em; }
.cut { text-align: center; color: var(--slate); letter-spacing: .6em; margin: 2rem 0; }
.after { margin-top: 3.5rem; padding-top: 2rem; border-top: 1px solid var(--rule); }
.after h2 { margin-top: 0; }
.btn-outline { background: transparent; color: var(--ink); border-color: var(--ink); }
.btn-outline:hover { background: var(--ink); color: var(--white); }
ol.chapters { padding-left: 1.6rem; margin: 0 0 1.4rem; }
ol.chapters li { margin-bottom: .25em; }
.page h3 { font-size: 1.1rem; margin: 1.6rem 0 .5rem; }
table.prices { border-collapse: collapse; margin: 0 0 1.2em; font-family: var(--sans); font-size: 1rem; }
table.prices th, table.prices td { text-align: left; padding: .55rem 1.4rem .55rem 0; border-bottom: 1px solid var(--rule); }
table.prices th { font-weight: 700; border-bottom: 2px solid var(--ink); }
.todo { background: var(--todo); color: #3d2c00; padding: 0 .3em; border-radius: 2px; }
p.todo { display: block; padding: .5rem .75rem; }

/* footer */
.site-footer { background: var(--ink); color: #c5d5e8; padding: 2.5rem 0; font-family: var(--sans); font-size: 1rem; }
.site-footer a { color: #e6efff; }
.site-footer .fine { font-size: .9rem; color: #9fb4cd; margin-bottom: .5em; }

@media print { .site-header, .site-footer, .btns { display: none; } body { background: #fff; } }