/* Shared by the headline pages: tokens, type, navigation, buttons, tiles, details, footer. */
:root {
  --ink: #1a1714; --ink-mid: #3d3935; --paper: #f5f2ee; --paper-mid: #ede9e3; --stone: #d4cfc9;
  --navy: #2b4a6f; --gold: #e8b75a; --gold-deep: #c9973a; --ink-rule: rgba(26,23,20,0.45);
  --on-dark: rgba(245,242,238,0.9); --on-dark-rule: rgba(245,242,238,0.3);
  --serif: Fraunces, Georgia, serif;
  --sans: "Source Sans 3", Helvetica, Arial, sans-serif;
  --gutter: clamp(1rem, 5vw, 4rem);
  --focus: #1a1714;
}
* { box-sizing: border-box; }
body { margin: 0; background: var(--ink); color: var(--ink); font-family: var(--sans); font-size: 1.0625rem; line-height: 1.5; overflow-wrap: break-word; }
h1, h2, h3, p, ol, ul { margin: 0; padding: 0; font-weight: 400; }
ol, ul { list-style: none; }
img { display: block; max-width: 100%; height: auto; }
a { color: inherit; }
main:focus { outline: none; }
.dark { --focus: #f5f2ee; }
.on-gold { --focus: #1a1714; }
:focus-visible { outline: 3px solid var(--focus); outline-offset: 3px; }
.inner { width: 100%; max-width: 1320px; margin: 0 auto; padding-left: var(--gutter); padding-right: var(--gutter); }
.skip { position: absolute; left: 1rem; top: -6rem; z-index: 20; background: var(--paper); color: var(--ink); padding: 0.75rem 1rem; font-weight: 600; }
.skip:focus { top: 1rem; }
.pad { padding-top: clamp(4rem, 8vw, 7rem); padding-bottom: clamp(4rem, 8vw, 7rem); }
.label { display: block; margin-bottom: 1.25rem; font-weight: 600; }
.h1 { font-family: var(--serif); font-weight: 300; font-size: clamp(2.75rem, 7.4vw, 6.25rem); line-height: 1.03; letter-spacing: -0.025em; }
.h2 { font-family: var(--serif); font-weight: 300; font-size: clamp(2.25rem, 5.4vw, 4.5rem); line-height: 1.05; letter-spacing: -0.025em; max-width: 60rem; }
.lead { max-width: 44rem; font-size: clamp(1.125rem, 1.8vw, 1.375rem); line-height: 1.4; }
.hero { padding-top: clamp(2.5rem, 7vw, 6rem); padding-bottom: clamp(3rem, 7vw, 6rem); }

.site-head { background: var(--ink); color: var(--paper); }
.site-head-row { display: flex; flex-wrap: wrap; gap: 0 1.5rem; align-items: center; justify-content: space-between; padding-top: 0.5rem; padding-bottom: 0.5rem; }
.brand { display: inline-flex; align-items: center; min-height: 44px; font-family: var(--serif); font-size: 1.375rem; font-weight: 300; color: var(--paper); text-decoration: none; }
.site-nav { display: flex; flex-wrap: wrap; align-items: center; }
.nav-link { display: inline-flex; align-items: center; min-height: 44px; padding: 0 0.625rem; color: var(--paper); font-weight: 600; text-decoration: none; }
.nav-link:hover, .nav-link[aria-current="page"] { text-decoration: underline; text-underline-offset: 0.3em; }
.nav-book { color: var(--gold); }

.btn { display: inline-flex; align-items: center; justify-content: center; min-height: 52px; padding: 0.625rem 1.75rem; font: 600 1.0625rem/1.2 var(--sans); text-decoration: none; border: 2px solid transparent; cursor: pointer; }
.btn-gold { background: var(--gold); color: var(--ink); border-color: var(--gold); }
.btn-gold:hover { background: var(--paper); border-color: var(--paper); }
.btn-line { background: transparent; color: var(--paper); border-color: var(--paper); }
.btn-line:hover { background: var(--paper); color: var(--ink); }
.btn-ink { background: var(--ink); color: var(--paper); border-color: var(--ink); }
.btn-ink:hover { background: var(--navy); border-color: var(--navy); }
.btn-out { background: transparent; color: var(--ink); border-color: var(--ink); }
.btn-out:hover { background: var(--ink); color: var(--paper); }
.acts { display: flex; flex-wrap: wrap; gap: 0.75rem; }

.wall { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 1px; background: var(--on-dark-rule); border: 1px solid var(--on-dark-rule); }
.tile { display: flex; flex-direction: column; gap: 0.5rem; min-height: 14rem; padding: 1.25rem; background: var(--ink); color: var(--paper); text-decoration: none; }
a.tile:focus-visible { outline-offset: -6px; }
.tile-n { font-family: var(--serif); font-weight: 300; font-size: clamp(2.25rem, 4.4vw, 3.75rem); line-height: 1.05; letter-spacing: -0.02em; color: var(--gold); }
.tile-c { flex-grow: 1; }
.tile-s { font-size: 0.9375rem; font-weight: 600; color: rgba(245,242,238,0.82); }
a.tile:hover { background: var(--gold); color: var(--ink); }
a.tile:hover .tile-n, a.tile:hover .tile-s { color: var(--ink); }
a.tile:hover:focus-visible { outline-color: var(--ink); }

.proofs { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 1px; background: var(--on-dark-rule); border: 1px solid var(--on-dark-rule); }
.proof { display: flex; flex-direction: column; gap: 0.5rem; min-height: 15rem; padding: 1.25rem; background: var(--ink); color: var(--paper); }
.proof-n { font-family: var(--serif); font-weight: 300; font-size: clamp(2.5rem, 5vw, 4.5rem); line-height: 1.05; letter-spacing: -0.025em; color: var(--gold); }
.proof-c { flex-grow: 1; font-size: clamp(1.0625rem, 1.5vw, 1.25rem); line-height: 1.35; }
.proof-s { font-size: 0.9375rem; font-weight: 600; color: rgba(245,242,238,0.82); }

.dotline { display: grid; grid-template-columns: repeat(var(--steps, 5), minmax(0, 1fr)); }
.dotstep { position: relative; padding: 3rem 1.25rem 0 0; font-family: var(--serif); font-weight: 300; font-size: clamp(1.25rem, 2.1vw, 1.75rem); line-height: 1.15; letter-spacing: -0.01em; }
.dotstep::before { content: ""; position: absolute; top: 9px; left: 0; right: 0; height: 2px; background: currentColor; }
.dotstep::after { content: ""; position: absolute; top: 0; left: 0; width: 20px; height: 20px; border-radius: 50%; background: currentColor; }
.dotstep:last-child::before { display: none; }

.detail { border-top: 1px solid var(--ink-rule); }
.detail:last-of-type { border-bottom: 1px solid var(--ink-rule); }
.detail > summary { display: grid; grid-template-columns: minmax(0, 1fr) 20px; gap: 1rem; align-items: center; min-height: 60px; padding: 0.75rem 0; font-size: 1.125rem; font-weight: 600; line-height: 1.3; cursor: pointer; list-style: none; }
.detail > summary::-webkit-details-marker { display: none; }
.detail > summary:hover { color: var(--navy); }
.detail-mark { width: 20px; height: 20px; }
.detail[open] .detail-mark { transform: rotate(45deg); }
.detail-body { max-width: 46rem; padding: 0 0 1.5rem; color: var(--ink-mid); }

.site-foot { background: var(--ink); border-top: 1px solid var(--on-dark-rule); padding: 1.25rem 0; }
.foot-row { display: flex; flex-wrap: wrap; }
.foot-link { display: inline-flex; align-items: center; min-height: 44px; padding-right: 1.25rem; color: rgba(245,242,238,0.85); text-decoration: none; }
.foot-link:hover { color: var(--paper); text-decoration: underline; text-underline-offset: 0.25em; }

@media (max-width: 900px) {
  .wall, .proofs { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .tile { min-height: 12.5rem; padding: 1rem; font-size: 1rem; }
}
@media (max-width: 520px) {
  .proofs { grid-template-columns: 1fr; }
  .proof { min-height: 0; gap: 1rem; }
}
@media (max-width: 820px) {
  .dotline { grid-template-columns: 1fr; }
  .dotstep { padding: 0 0 2rem 2.5rem; }
  .dotstep::before { top: 0; bottom: 0; left: 9px; right: auto; width: 2px; height: auto; }
  .dotstep:last-child { padding-bottom: 0; }
}
@media (prefers-reduced-motion: no-preference) {
  html { scroll-behavior: smooth; }
  .btn, a.tile { transition: background-color 0.2s, color 0.2s, border-color 0.2s; }
  .detail-mark { transition: transform 0.25s ease; }
  .in-a { animation: ina 0.4s cubic-bezier(0.2, 0.7, 0.2, 1) both; }
  .in-b { animation: inb 0.4s cubic-bezier(0.2, 0.7, 0.2, 1) both; }
}
@keyframes ina { from { opacity: 0; transform: translateY(12px); } to { opacity: 1; transform: none; } }
@keyframes inb { from { opacity: 0; transform: translateY(12px); } to { opacity: 1; transform: none; } }