/* The site's type and palette come from the book, so the two read as one product. */

@font-face { font-family: "XCharter"; src: url("/fonts/xcharter-roman.woff2") format("woff2"); font-weight: 400; font-style: normal; font-display: swap; }
@font-face { font-family: "XCharter"; src: url("/fonts/xcharter-italic.woff2") format("woff2"); font-weight: 400; font-style: italic; font-display: swap; }
@font-face { font-family: "XCharter"; src: url("/fonts/xcharter-bold.woff2") format("woff2"); font-weight: 700; font-style: normal; font-display: swap; }

:root {
  --ink: #1a1a1a;
  --muted: #5f5f5f;
  --rule: #d6d6d6;
  --accent: #1f4e79;       /* book2 theme: c.accent (digital) */
  --accent-dark: #173b5c;
  --member: #a8c6e0;       /* book2 theme: c.member */
  --wash: #f2f6fa;         /* book2 theme: c.wash */
  --paper: #ffffff;
  --error: #9b1c1c;
  --serif: "XCharter", Charter, "Bitstream Charter", Georgia, serif;
  --sans: system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  --narrow: 38rem;
  --wide: 60rem;
}

* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }
body { margin: 0; background: var(--paper); color: var(--ink); font: 18px/1.6 var(--serif); }
a { color: var(--accent); }
a:hover { color: var(--accent-dark); }
:focus-visible { outline: 3px solid var(--member); outline-offset: 2px; }

.page { max-width: var(--wide); margin: 0 auto; padding: 0 16px 4rem; }
section { margin-top: 5rem; }
h1, h2, h3 { line-height: 1.15; }
h1 { font-size: clamp(2.3rem, 7vw, 3.6rem); margin: 0.35em 0 0.4em; letter-spacing: -0.01em; }
h2 { font-size: clamp(1.5rem, 4vw, 1.9rem); margin: 0 0 1rem; }
h3 { font-size: 1.15rem; margin: 0 0 0.5rem; }
.kicker { color: var(--accent); font: 700 0.75rem/1.3 var(--sans); letter-spacing: 0.12em; text-transform: uppercase; margin: 0; }

.button, button {
  display: inline-block; font: 600 1rem/1.2 var(--sans); color: #fff; background: var(--accent);
  border: 0; border-radius: 4px; padding: 0.8rem 1.2rem; cursor: pointer; text-decoration: none;
}
.button:hover, button:hover { background: var(--accent-dark); color: #fff; }
button:disabled { opacity: 0.6; cursor: default; }

/* ------------------------------------------------------------------- hero */
.hero { display: grid; gap: 3rem; align-items: center; padding-top: clamp(2.5rem, 9vh, 6rem); }
@media (min-width: 800px) { .hero { grid-template-columns: 1fr 340px; gap: 4rem; } }
.lede { font-size: 1.2rem; color: var(--muted); margin: 0 0 1.75rem; max-width: 34rem; }
.actions { display: flex; flex-wrap: wrap; align-items: center; gap: 0.75rem 1.25rem; }
.price { margin: 0; font: 600 0.95rem/1.3 var(--sans); }
.price span { color: var(--muted); font-weight: 400; }
.button-secondary { background: transparent; color: var(--accent); box-shadow: inset 0 0 0 2px var(--accent); }
.button-secondary:hover { background: var(--wash); color: var(--accent-dark); }
#buy-message:empty { display: none; }
.facts { margin: 1.5rem 0 0; font: 0.85rem/1.4 var(--sans); color: var(--muted); }
.hero-cover img {
  display: block; width: 100%; max-width: 340px; height: auto; margin: 0 auto;
  transform: rotate(2deg); border-radius: 2px;
  box-shadow: 0 1px 2px rgb(0 0 0 / 0.12), 0 14px 36px rgb(0 0 0 / 0.18);
}
@media (max-width: 799px) { .hero-cover img { max-width: min(70vw, 300px); } }

/* ------------------------------------------------------------------ parts */
.part-grid { display: grid; gap: 1.5rem; }
@media (min-width: 800px) { .part-grid { grid-template-columns: repeat(3, 1fr); gap: 2rem; } }
.part { border-top: 3px solid var(--accent); padding-top: 1rem; }
.part p { margin: 0; color: var(--muted); font-size: 1rem; }

/* --------------------------------------------------------------- showcase */
.shot { margin: 3rem 0 0; }
.shot img { display: block; width: 100%; height: auto; border: 1px solid var(--rule); box-shadow: 0 6px 20px rgb(0 0 0 / 0.08); }
.shot-page img { max-width: 480px; margin: 0 auto; }
.shot figcaption { max-width: var(--narrow); margin: 0.9rem auto 0; font-size: 0.95rem; color: var(--muted); text-align: center; }

/* ----------------------------------------------------------- free chapter */
.free-chapter, .faq { max-width: var(--narrow); margin-left: auto; margin-right: auto; }
/* Section headings sit centred over their content, which is centred on the page. */
.parts > h2, .showcase > h2, .faq > h2 { text-align: center; }
.parts > h2, .showcase > h2 { margin-bottom: 2rem; }
.free-chapter { padding: 2rem 1.5rem; background: var(--wash); border-left: 3px solid var(--accent); }
.free-chapter > p { margin-top: 0; }
label { display: block; font: 600 0.85rem/1.4 var(--sans); margin-bottom: 0.35rem; }
.field-row { display: flex; flex-wrap: wrap; gap: 0.5rem; }
input[type=email] {
  flex: 1 1 14rem; min-width: 0; font: 1rem/1.4 var(--sans); color: var(--ink);
  padding: 0.75rem; border: 1px solid #b9c3cc; border-radius: 4px; background: var(--paper);
}
.consent, .small { font-size: 0.85rem; color: var(--muted); margin: 0.75rem 0 0; }
.form-message { min-height: 1.4em; font-size: 0.9rem; color: var(--error); margin: 0.5rem 0 0; }
.download p:first-child { font-weight: 700; }
.hp { position: absolute; left: -10000px; width: 1px; height: 1px; overflow: hidden; }

/* -------------------------------------------------------------------- faq */
.faq details { border-bottom: 1px solid var(--rule); }
.faq details:first-of-type { border-top: 1px solid var(--rule); }
.faq summary { cursor: pointer; padding: 1rem 2rem 1rem 0; font-weight: 700; list-style: none; position: relative; }
.faq summary::-webkit-details-marker { display: none; }
.faq summary::after { content: "+"; position: absolute; right: 0.25rem; color: var(--accent); font: 400 1.4rem/1 var(--sans); top: 1.05rem; }
.faq details[open] summary::after { content: "−"; }
.faq details p { margin: 0 0 1.25rem; color: var(--muted); }

/* ------------------------------------------------------------------ thanks */
.thanks-state[hidden] { display: none; }
.thanks-state .button { margin: 0.5rem 0 1rem; }

/* ------------------------------------------------------ other pages, footer */
.prose { max-width: var(--narrow); padding-top: 3rem; }
.prose h2 { margin-top: 2.5rem; font-size: 1.35rem; }
.prose ul { padding-left: 1.2rem; }
.prose code { font-size: 0.85em; }
.footer { border-top: 1px solid var(--rule); padding: 1.5rem 16px 3rem; text-align: center; font: 0.85rem/1.6 var(--sans); color: var(--muted); }
.footer p { margin: 0.25rem 0; }