.home-beginner-callout,
.start-here-lesson,
.concept-first-lesson {
  width: min(920px, calc(100% - 32px));
  margin: 26px auto 42px;
}

.home-beginner-callout {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr) auto;
  gap: 18px;
  align-items: center;
  padding: 17px 20px;
  border: 1px solid var(--line-strong);
  border-radius: 12px;
  background: var(--warm-soft);
  font-family: var(--ui-font);
}

.home-beginner-callout strong {
  font-size: 15px;
}

.home-beginner-callout span {
  color: var(--muted);
  font-size: 14px;
}

.home-beginner-callout a {
  font-weight: 750;
  white-space: nowrap;
}

.start-here-lesson,
.concept-first-lesson {
  padding: clamp(22px, 4vw, 42px);
  border: 1px solid var(--line);
  border-radius: 14px;
  background: var(--surface);
  box-shadow: var(--shadow);
}

.start-here-lesson {
  border-top: 5px solid var(--warm);
}

.concept-first-lesson {
  border-top: 5px solid var(--block);
}

.reader-mode-switch {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  margin: -6px 0 30px;
  padding-bottom: 18px;
  border-bottom: 1px solid var(--line);
  font-family: var(--ui-font);
}

.reader-mode-switch > span {
  margin-right: 6px;
  font-size: 13px;
  font-weight: 800;
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

.reader-mode-switch button {
  min-width: 76px;
  padding: 7px 12px;
  border: 1px solid var(--line-strong);
  border-radius: 999px;
  color: var(--muted);
  background: var(--surface);
  cursor: pointer;
  font-size: 13px;
  font-weight: 700;
}

.reader-mode-switch button[aria-pressed="true"] {
  color: #fff;
  border-color: var(--block-dark);
  background: var(--block-dark);
}

.reader-mode-switch small {
  flex: 1 1 250px;
  color: var(--quiet);
  font-size: 12px;
}

.reader-layer > h2,
.start-here-lesson > h2 {
  max-width: 22ch;
  margin: 4px 0 16px;
  font-size: clamp(30px, 4vw, 45px);
  line-height: 1.08;
  letter-spacing: -0.025em;
}

.reader-hook {
  max-width: 68ch;
  margin: 0 0 28px;
  color: var(--muted);
  font-size: clamp(18px, 2vw, 21px);
  line-height: 1.6;
}

.reader-formula {
  overflow-x: auto;
  margin: 18px 0;
  padding: 18px 20px;
  border-left: 4px solid var(--block);
  background: var(--block-soft);
  text-align: center;
}

.reader-note {
  color: var(--muted);
  font-size: 15px;
}

.learning-circuit {
  margin: 28px 0;
  padding: 18px;
  border: 1px solid var(--line);
  border-radius: 12px;
  background: var(--surface-subtle);
}

.learning-circuit figcaption {
  margin-bottom: 18px;
  color: var(--muted);
  font-family: var(--ui-font);
  font-size: 13px;
  font-weight: 700;
}

.learning-circuit-body {
  display: grid;
  gap: 18px;
}

.learning-wire-row {
  display: grid;
  grid-template-columns: 48px minmax(70px, auto) minmax(260px, 1fr) minmax(90px, auto);
  align-items: center;
  gap: 10px;
  font-family: var(--ui-font);
}

.wire-name {
  color: var(--quiet);
  font-family: var(--mono-font);
  font-size: 12px;
}

.wire-input,
.wire-output {
  font-family: var(--body-font);
  font-size: 15px;
  white-space: nowrap;
}

.learning-wire {
  position: relative;
  min-height: 52px;
  display: flex;
  justify-content: space-around;
  align-items: center;
  gap: 22px;
  padding: 0 12px;
}

.learning-wire > i {
  position: absolute;
  left: 0;
  right: 0;
  top: 50%;
  height: 2px;
  background: var(--line-strong);
}

.learning-gate {
  position: relative;
  z-index: 1;
  min-width: 42px;
  min-height: 42px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 5px 8px;
  border: 2px solid var(--block-dark);
  border-radius: 7px;
  color: var(--block-dark);
  background: var(--surface);
  font-family: var(--ui-font);
  font-size: 12px;
  font-weight: 800;
  text-align: center;
}

.learning-gate.empty {
  border-color: transparent;
  background: transparent;
}

.intuition-steps {
  counter-reset: lesson-step;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
  margin: 26px 0;
  padding: 0;
  list-style: none;
}

.intuition-steps li {
  counter-increment: lesson-step;
  position: relative;
  min-height: 106px;
  padding: 17px 18px 17px 58px;
  border: 1px solid var(--line);
  border-radius: 10px;
  background: var(--surface-subtle);
}

.intuition-steps li::before {
  content: counter(lesson-step);
  position: absolute;
  left: 17px;
  top: 17px;
  width: 27px;
  height: 27px;
  display: grid;
  place-items: center;
  border-radius: 50%;
  color: #fff;
  background: var(--state-dark);
  font-family: var(--ui-font);
  font-size: 12px;
  font-weight: 800;
}

.intuition-steps strong,
.intuition-steps span {
  display: block;
}

.intuition-steps strong {
  margin-bottom: 5px;
  font-family: var(--ui-font);
  font-size: 14px;
}

.intuition-steps span {
  color: var(--muted);
  font-size: 14px;
  line-height: 1.5;
}

.textbook-source-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
  margin-top: 30px;
}

.textbook-source {
  padding: 16px 18px;
  border: 1px solid var(--line);
  border-radius: 10px;
  background: var(--paper);
}

.textbook-source h4 {
  margin: 2px 0 3px;
  font-size: 16px;
}

.textbook-source p {
  margin: 6px 0;
  color: var(--muted);
  font-size: 13px;
}

.textbook-source .source-authors {
  color: var(--quiet);
  font-family: var(--ui-font);
  font-size: 12px;
}

.textbook-source blockquote {
  margin: 12px 0;
  padding-left: 12px;
  border-left: 3px solid var(--warm);
  color: var(--ink);
  font-style: italic;
  font-size: 15px;
}

.lean-lens {
  overflow-x: auto;
  margin: 20px 0;
  padding: 20px;
  border-radius: 10px;
  color: var(--code-ink);
  background: var(--code-bg);
  font-size: 13px;
}

body.reader-mode-enabled .reader-layer {
  display: none;
}

body.reader-mode-enabled[data-reader-mode="concept"] [data-reader-layer="concept"],
body.reader-mode-enabled[data-reader-mode="math"] [data-reader-layer="math"],
body.reader-mode-enabled[data-reader-mode="lean"] [data-reader-layer="lean"] {
  display: block;
}

body.reader-mode-enabled:not([data-reader-mode="lean"]) main .result {
  display: none;
}

@media (max-width: 760px) {
  .home-beginner-callout {
    grid-template-columns: 1fr;
    gap: 8px;
  }

  .reader-mode-switch {
    align-items: flex-start;
  }

  .reader-mode-switch small {
    flex-basis: 100%;
  }

  .learning-wire-row {
    grid-template-columns: 34px minmax(54px, auto) minmax(190px, 1fr) minmax(70px, auto);
    gap: 5px;
    overflow-x: auto;
  }

  .learning-wire {
    gap: 10px;
  }

  .intuition-steps,
  .textbook-source-grid {
    grid-template-columns: 1fr;
  }

  .start-here-lesson,
  .concept-first-lesson,
  .home-beginner-callout {
    width: min(100% - 20px, 920px);
  }
}

@media print {
  .reader-mode-switch {
    display: none;
  }

  body.reader-mode-enabled .reader-layer {
    display: block !important;
  }
}