/* Study typography — readable prose + clear code (books) */

:root {
  --prose: "IBM Plex Sans", "Noto Sans", system-ui, sans-serif;
  --read-size: 1.0625rem;
  --read-lh: 1.7;
  --read-pad: clamp(1.1rem, 2.5vw, 1.75rem);
  --section-gap: 1.35rem;
}

html {
  scroll-padding-top: 4.25rem;
  font-size: 16px;
}

/* —— Cover —— */
.cover {
  padding-block: 3.5rem 2.25rem !important;
}
.cover h1 {
  font-family: var(--prose) !important;
  font-weight: 600 !important;
  letter-spacing: -0.025em !important;
}
.cover-sub {
  font-family: var(--prose) !important;
  font-size: 1.05rem !important;
  line-height: 1.5 !important;
}
.cover-meta {
  margin-top: 1rem !important;
  font-size: 0.8rem !important;
}

/* —— Structure rhythm —— */
.content {
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
}

.part {
  margin: 3rem 0 1.5rem !important;
  padding: 0 0 0.55rem !important;
  font-family: var(--prose) !important;
  font-size: clamp(1.25rem, 2.6vw, 1.55rem) !important;
  font-weight: 600 !important;
  letter-spacing: -0.02em !important;
  scroll-margin-top: 4.25rem;
}
.part:first-child {
  margin-top: 0.5rem !important;
}

.chapter {
  margin: 0 0 2.25rem !important;
}
.chapter-header {
  margin: 2rem 0 1.15rem !important;
  padding: 0.9rem var(--read-pad) !important;
  scroll-margin-top: 4.25rem;
}
.chapter-meta {
  font-family: var(--mono) !important;
  font-size: 0.72rem !important;
  margin-bottom: 0.35rem !important;
}
.chapter-title {
  font-family: var(--prose) !important;
  font-size: clamp(1.05rem, 2vw, 1.25rem) !important;
  font-weight: 600 !important;
  letter-spacing: -0.015em !important;
  line-height: 1.3 !important;
}

/* —— Lesson cards —— */
.lesson {
  margin-bottom: 1.75rem !important;
  scroll-margin-top: 4.25rem;
}
.lesson-header {
  padding: 1.25rem var(--read-pad) 0.75rem !important;
  border-left-width: 2px !important;
  border-left-color: var(--accent) !important;
}
.lesson-meta {
  font-family: var(--mono) !important;
  font-size: 0.72rem !important;
  letter-spacing: 0.06em !important;
  margin-bottom: 0.45rem !important;
}
.lesson-header h2 {
  font-family: var(--prose) !important;
  font-size: clamp(1.15rem, 2.2vw, 1.4rem) !important;
  font-weight: 600 !important;
  letter-spacing: -0.02em !important;
  line-height: 1.3 !important;
  margin: 0 0 0.5rem !important;
  text-transform: none !important;
}
.lesson-header .source {
  margin: 0 !important;
  font-size: 0.75rem !important;
}

/* —— Prose body —— */
.lesson-body,
.practice-body {
  font-family: var(--prose) !important;
  font-size: var(--read-size) !important;
  line-height: var(--read-lh) !important;
  color: color-mix(in srgb, var(--ink) 94%, transparent);
  padding: 0.35rem var(--read-pad) 1.4rem !important;
  max-width: none !important;
}

.lesson-body > :first-child,
.practice-body > :first-child {
  margin-top: 0.15rem !important;
}

.lesson-body p,
.practice-body p {
  margin: 0.85em 0 !important;
}

.lesson-body h3,
.practice-body h3 {
  font-family: var(--prose) !important;
  font-size: 1.05rem !important;
  font-weight: 600 !important;
  letter-spacing: -0.015em !important;
  color: var(--ink) !important;
  margin: 1.85em 0 0.55em !important;
  padding-top: 0.85em;
  border-top: 1px solid var(--line);
  scroll-margin-top: 4.25rem;
}
.lesson-body h3:first-child,
.practice-body h3:first-child {
  margin-top: 0.75em !important;
  padding-top: 0;
  border-top: none;
}

.lesson-body h4,
.practice-body h4 {
  font-family: var(--prose) !important;
  font-size: 0.95rem !important;
  font-weight: 600 !important;
  margin: 1.4em 0 0.4em !important;
  color: var(--ink) !important;
}

.lesson-body ul,
.lesson-body ol,
.practice-body ul,
.practice-body ol {
  margin: 0.85em 0 !important;
  padding-left: 1.4rem !important;
}

.lesson-body li,
.practice-body li {
  margin: 0.4em 0 !important;
  padding-left: 0.15rem;
}

.lesson-body li::marker,
.practice-body li::marker {
  color: var(--faint);
}

.lesson-body strong,
.practice-body strong {
  color: var(--ink);
  font-weight: 600;
}

.lesson-body a,
.practice-body a {
  text-decoration: underline;
  text-decoration-color: color-mix(in srgb, var(--link) 45%, transparent);
  text-underline-offset: 0.18em;
}
.lesson-body a:hover,
.practice-body a:hover {
  text-decoration-color: var(--link);
}

/* —— Callouts / notes —— */
.lesson-body blockquote,
.practice-body blockquote {
  margin: 1.15em 0 !important;
  padding: 0.75rem 1rem !important;
  border-left: 2px solid var(--accent) !important;
  background: color-mix(in srgb, var(--accent) 6%, var(--surface-2)) !important;
  color: color-mix(in srgb, var(--ink) 88%, transparent) !important;
  font-size: 0.97em;
}
.lesson-body blockquote p,
.practice-body blockquote p {
  margin: 0.35em 0 !important;
}
.lesson-body blockquote p:first-child,
.practice-body blockquote p:first-child {
  margin-top: 0 !important;
}

.verse {
  margin: 1em 0;
  padding: 0.55rem 0 0.55rem 0.9rem;
  border-left: 2px solid var(--line-strong);
  color: var(--muted);
}

/* —— Tables —— */
.lesson-body table,
.practice-body table {
  display: block;
  width: max-content;
  max-width: 100%;
  overflow-x: auto;
  margin: 1.15em 0 !important;
  font-size: 0.92rem;
  line-height: 1.45;
  border: 1px solid var(--line);
}
.lesson-body th,
.lesson-body td,
.practice-body th,
.practice-body td {
  padding: 0.5em 0.75em !important;
  white-space: nowrap;
}
.lesson-body th,
.practice-body th {
  font-family: var(--mono);
  font-size: 0.78em;
  letter-spacing: 0.03em;
  text-transform: uppercase;
}

/* —— Definitions / algorithms —— */
dl.mapping,
ol.algo {
  margin: 1.15em 0 !important;
  padding: 0.9rem 1rem !important;
  font-size: 0.97em;
  line-height: 1.55;
}
dl.mapping {
  gap: 0.4rem 1rem !important;
}
dl.mapping dt {
  color: var(--accent);
  font-weight: 500 !important;
}
ol.algo li {
  margin: 0.45em 0 !important;
}

/* —— Inline + block code —— */
.lesson-body :not(pre) > code,
.practice-body :not(pre) > code {
  font-family: var(--mono) !important;
  font-size: 0.86em !important;
  color: var(--accent) !important;
  background: color-mix(in srgb, var(--accent) 8%, var(--surface-2)) !important;
  border: 1px solid color-mix(in srgb, var(--accent) 22%, var(--line)) !important;
  padding: 0.12em 0.38em !important;
  border-radius: 0 !important;
  white-space: nowrap;
}

.lesson-body pre,
.practice-body pre,
.lesson-body .code-window,
.practice-body .code-window {
  max-width: none;
  width: 100%;
  margin: 1.2em 0 !important;
  font-size: 0.84rem !important;
  line-height: 1.55 !important;
}

.lesson-body .code-window,
.practice-body .code-window {
  margin-inline: 0;
}

.code-window-bar {
  min-height: 2rem;
  padding-inline: 0.75rem !important;
}

.code-window pre {
  padding: 0.95em 1.05em !important;
}

/* —— Practice —— */
.lesson.practice .lesson-header {
  border-left-color: var(--practice) !important;
}
.lesson.practice .lesson-meta::before {
  content: "practice · ";
  opacity: 0.75;
}
.difficulty {
  display: inline-flex !important;
  align-items: center;
  gap: 0.35rem;
  margin: 0.15rem 0 0.85rem !important;
  padding: 0.2rem 0.55rem !important;
  font-family: var(--mono) !important;
}
.practice-body h3 {
  border-top-style: dashed !important;
}
.practice-body h4 {
  color: var(--practice) !important;
  font-family: var(--mono) !important;
  font-size: 0.82rem !important;
  letter-spacing: 0.04em !important;
  text-transform: uppercase;
  margin-top: 1.6em !important;
}

/* —— Lesson footer nav —— */
.lesson-nav {
  padding: 0.85rem var(--read-pad) !important;
  font-family: var(--mono) !important;
  font-size: 0.78rem !important;
  gap: 1rem !important;
}
.lesson-nav a {
  color: var(--muted) !important;
  text-decoration: none !important;
}
.lesson-nav a:hover {
  color: var(--accent) !important;
}
.nav-prev::before {
  content: "← ";
  color: var(--faint);
}
.nav-next::after {
  content: " →";
  color: var(--faint);
}
.nav-toc {
  letter-spacing: 0.04em;
}

/* —— Resume —— */
.resume-banner {
  font-family: var(--prose);
  font-size: 0.92rem !important;
  padding: 0.8rem var(--read-pad) !important;
  margin-bottom: 1.25rem !important;
  align-items: center;
  gap: 1rem !important;
}
.resume-banner a {
  font-family: var(--mono);
  font-size: 0.8rem;
  font-weight: 500;
  text-decoration: none !important;
  border: 1px solid color-mix(in srgb, var(--accent) 45%, var(--line));
  padding: 0.3rem 0.65rem;
  color: var(--accent) !important;
}
.resume-banner a:hover {
  background: var(--accent-dim);
}

/* —— Images —— */
.lesson-body img,
.practice-body img {
  margin: 1.25em 0 !important;
  border: 1px solid var(--line);
  max-width: 100%;
}

/* —— Soft focus on active lesson while scrolling (subtle) —— */
.lesson:target,
.lesson:has(:target) {
  border-color: color-mix(in srgb, var(--accent) 35%, var(--line)) !important;
}

@media (max-width: 720px) {
  :root {
    --read-size: 1rem;
    --read-lh: 1.65;
  }

  .lesson-body,
  .practice-body,
  .lesson-header,
  .lesson-nav,
  .chapter-header {
    padding-inline: 1rem !important;
  }

  .lesson-body :not(pre) > code,
  .practice-body :not(pre) > code {
    white-space: normal;
  }
}

@media print {
  .lesson-body,
  .practice-body {
    font-size: 11pt !important;
    line-height: 1.45 !important;
    color: #111 !important;
  }
}