.module {
  margin-bottom: 120px;
  scroll-margin-top: 30px;
  transition: opacity .25s ease, filter .25s ease;
}
.module-heading {
  display: grid;
  padding-bottom: 24px;
  grid-template-columns: 72px 1fr minmax(190px, .55fr);
  gap: 20px;
  align-items: end;
  border-bottom: 1px solid var(--ink);
}
.module-number { color: var(--blue); font: 500 12px/1 var(--mono); }
.module-heading h2 { margin: 0; font: 600 34px/1.1 var(--display); letter-spacing: -.04em; }
.module-heading p { margin: 0; color: var(--muted); font-size: 12px; }
.topic-list { border-bottom: 1px solid var(--ink); }

.topic {
  border-top: 1px solid var(--line);
  transition: opacity .25s ease, background-color .2s ease;
}
.topic:first-child { border-top: 0; }
.topic[open] { background: var(--white); }
.topic summary {
  display: grid;
  min-height: 92px;
  padding: 22px 20px 22px 72px;
  grid-template-columns: minmax(0, 1fr) minmax(170px, .55fr) 30px;
  gap: 20px;
  align-items: center;
  cursor: pointer;
  list-style: none;
}
.topic summary::-webkit-details-marker { display: none; }
.topic summary:hover { background: rgba(255, 255, 255, .45); }
.topic-title { display: flex; gap: 16px; align-items: baseline; }
.topic-index { color: var(--blue); font: 400 9px/1 var(--mono); }
.topic h3 { margin: 0; font: 600 18px/1.25 var(--display); letter-spacing: -.02em; }
.topic-summary { margin: 0; color: var(--muted); font-size: 12px; line-height: 1.5; }
.toggle-mark { position: relative; width: 28px; height: 28px; border: 1px solid var(--ink); border-radius: 50%; }
.toggle-mark::before, .toggle-mark::after { position: absolute; top: 13px; left: 8px; width: 10px; height: 1px; background: currentColor; content: ""; }
.toggle-mark::after { transform: rotate(90deg); transition: transform .2s ease; }
.topic[open] .toggle-mark { color: var(--white); border-color: var(--blue); background: var(--blue); }
.topic[open] .toggle-mark::after { transform: rotate(0); }

.topic-body { padding: 14px 72px 44px; }
.lesson-grid { display: grid; max-width: 830px; grid-template-columns: 1.3fr .7fr; gap: 54px; }
.lesson-copy > p { margin-bottom: 22px; font-size: 15px; line-height: 1.75; }
.lesson-copy ul { margin: 0 0 24px; padding: 0; list-style: none; }
.lesson-copy li { position: relative; margin-bottom: 10px; padding-left: 18px; color: var(--muted); font-size: 13px; }
.lesson-copy li::before { position: absolute; left: 0; color: var(--blue); content: "→"; }
.lesson-aside { padding-left: 20px; border-left: 1px solid var(--line); }
.lesson-aside b { display: block; margin-bottom: 8px; color: var(--blue); font: 500 9px/1 var(--mono); letter-spacing: .12em; text-transform: uppercase; }
.lesson-aside p { color: var(--muted); font-size: 12px; }
pre { margin: 22px 0 0; padding: 18px; overflow-x: auto; color: #dce7e2; background: #19231f; font: 400 11px/1.75 var(--mono); }
code { font-family: var(--mono); }
.lesson-footer { display: flex; margin-top: 28px; gap: 12px; align-items: center; }
.read-button, .download-button {
  padding: 9px 12px;
  border: 1px solid var(--line);
  background: transparent;
  cursor: pointer;
  font: 500 10px/1 var(--mono);
}
.read-button:hover, .download-button:hover { border-color: var(--blue); color: var(--blue); }
.read-button.is-read { border-color: var(--ink); color: var(--white); background: var(--ink); }
.download-button { display: inline-block; }

body.has-focus .module:not(.is-active) { opacity: .07; filter: blur(1.5px); }
body.has-focus .module.is-active .topic:not(.is-active) { opacity: .12; }
.focus-toast {
  position: fixed;
  z-index: 10;
  right: 22px;
  bottom: 22px;
  display: flex;
  padding: 8px 8px 8px 14px;
  align-items: center;
  gap: 18px;
  color: var(--white);
  background: var(--blue);
  opacity: 0;
  pointer-events: none;
  transform: translateY(12px);
  transition: .2s ease;
  font: 400 10px/1 var(--mono);
}
body.has-focus .focus-toast { opacity: 1; pointer-events: auto; transform: translateY(0); }
.focus-toast button { padding: 7px 9px; border: 0; background: var(--white); cursor: pointer; color: var(--ink); font: 500 9px/1 var(--mono); }

.disclaimer { width: var(--page); margin: auto; padding: 80px 0 100px; border-top: 1px solid var(--ink); }
.disclaimer > div { display: grid; grid-template-columns: 1fr 1fr; gap: 100px; }
.disclaimer h2 { margin: 0; font: 600 clamp(38px, 4vw, 60px)/1 var(--display); letter-spacing: -.055em; }
.disclaimer h2 span { color: var(--blue); font-style: italic; }
.disclaimer div p { max-width: 580px; color: var(--muted); font-size: 13px; line-height: 1.8; }
.site-footer { display: flex; width: var(--page); min-height: 120px; margin: auto; align-items: center; justify-content: space-between; border-top: 1px solid var(--line); }
.site-footer p, .site-footer > a:last-child { margin: 0; color: var(--muted); font: 400 10px/1 var(--mono); }