/* ============================================================
   Курс частного пилота — лекционные конспекты
   Тёмная тема, упор на читаемый длинный текст, боксы по смыслу.
   ============================================================ */

:root {
  --bg:          #0e1117;
  --bg-soft:     #161b22;
  --bg-card:     #1c232c;
  --bg-card-2:   #222a35;
  --line:        #2a3340;
  --line-soft:   rgba(255,255,255,0.06);

  --text:        #e6edf3;
  --text-dim:    #8b96a3;
  --text-muted:  #6b7480;

  --accent:      #6fb1ff;       /* blue — основной */
  --accent-soft: rgba(111,177,255,0.10);
  --accent-line: rgba(111,177,255,0.28);

  --term:        #b08bff;       /* purple — термины */
  --term-soft:   rgba(176,139,255,0.10);
  --term-line:   rgba(176,139,255,0.28);

  --danger:      #ff8a8a;       /* red — Вопрос Росавиации */
  --danger-soft: rgba(255,138,138,0.08);
  --danger-line: rgba(255,138,138,0.30);

  --warn:        #ffc26b;       /* amber — безопасность */
  --warn-soft:   rgba(255,194,107,0.10);
  --warn-line:   rgba(255,194,107,0.30);

  --gray-soft:   rgba(139,150,163,0.10);
  --gray-line:   rgba(139,150,163,0.22);

  --serif: "Iowan Old Style", "Charter", "Cambria", "Georgia", serif;
  --sans:  -apple-system, BlinkMacSystemFont, "Inter", "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --mono:  "JetBrains Mono", "SF Mono", "Menlo", "Consolas", monospace;
}

* { box-sizing: border-box; }

html, body {
  margin: 0; padding: 0;
  background:
    radial-gradient(900px 500px at 90% -5%, #1c2a45 0%, transparent 60%),
    radial-gradient(700px 400px at -10% 10%, #16243a 0%, transparent 60%),
    var(--bg);
  color: var(--text);
  font-family: var(--sans);
  font-size: 17px;
  line-height: 1.72;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

::selection { background: rgba(111,177,255,0.30); color: #fff; }

.wrap {
  max-width: 780px;
  margin: 0 auto;
  padding: 28px 24px 96px;
}

/* ============== STICKY SITE HEADER + SEARCH ============== */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(14, 17, 23, 0.78);
  backdrop-filter: saturate(160%) blur(14px);
  -webkit-backdrop-filter: saturate(160%) blur(14px);
  border-bottom: 1px solid var(--line);
}
.site-header-inner {
  max-width: 780px;
  margin: 0 auto;
  padding: 12px 24px;
  display: block;
}

.search-wrap {
  position: relative;
  width: 100%;
  max-width: 560px;
  margin: 0 auto;
}
.search-input {
  display: block;
  width: 100%;
  background: var(--bg-card);
  border: 1px solid var(--line);
  border-radius: 10px;
  padding: 10px 14px 10px 38px;
  color: var(--text);
  font-size: 14.5px;
  font-family: var(--sans);
  line-height: 1.3;
  outline: none;
  appearance: none;
  -webkit-appearance: none;
  transition: border-color 0.2s, background 0.2s, box-shadow 0.2s;
  background-image: url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='%238b96a3' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'><circle cx='11' cy='11' r='7'/><path d='m21 21-4.3-4.3'/></svg>");
  background-repeat: no-repeat;
  background-position: 12px center;
  background-size: 15px 15px;
}
.search-input::placeholder { color: var(--text-muted); }
.search-input::-webkit-search-decoration,
.search-input::-webkit-search-cancel-button,
.search-input::-webkit-search-results-button,
.search-input::-webkit-search-results-decoration { -webkit-appearance: none; appearance: none; }
.search-input:focus {
  border-color: var(--accent-line);
  background-color: var(--bg-card-2);
  box-shadow: 0 0 0 3px rgba(111,177,255,0.12);
}

.search-results {
  position: absolute;
  top: calc(100% + 8px);
  left: 0;
  right: 0;
  background: var(--bg-card);
  border: 1px solid var(--line);
  border-radius: 12px;
  max-height: 70vh;
  overflow-y: auto;
  box-shadow: 0 14px 44px rgba(0, 0, 0, 0.55);
  z-index: 110;
  padding: 6px;
}
.search-results[hidden] { display: none; }
.search-result {
  display: block;
  padding: 12px 14px;
  border-radius: 8px;
  text-decoration: none;
  color: inherit;
  border: 0;
  transition: background 0.12s;
}
.search-result:hover,
.search-result.is-focused {
  background: var(--bg-card-2);
  border: 0;
}
.search-result + .search-result { margin-top: 2px; }
.search-result .badge {
  display: inline-block;
  font-size: 10.5px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--accent);
  font-weight: 700;
  margin-bottom: 4px;
}
.search-result .title {
  font-size: 14.5px;
  font-weight: 600;
  margin-bottom: 4px;
  color: var(--text);
  line-height: 1.35;
}
.search-result .snippet {
  font-size: 13px;
  color: var(--text-dim);
  line-height: 1.5;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}
.search-result mark {
  background: rgba(111, 177, 255, 0.25);
  color: var(--text);
  padding: 0 2px;
  border-radius: 3px;
}
.search-hint,
.search-empty {
  padding: 14px 16px;
  color: var(--text-muted);
  font-size: 13px;
}
.search-empty b { color: var(--text); }

/* ============== TOP NAV / BACK LINK ============== */
.back {
  display: inline-flex; align-items: center; gap: 8px;
  color: var(--text-dim); text-decoration: none;
  font-size: 13px; margin-bottom: 28px;
  font-family: var(--sans);
  transition: color 0.2s, transform 0.2s;
}
.back::before { content: "←"; display: inline-block; transition: transform 0.2s; }
.back:hover { color: var(--accent); }
.back:hover::before { transform: translateX(-2px); }

/* ============== HERO ============== */
.hero { margin-bottom: 56px; }
.site-updated {
  color: var(--text-dim);
  font-size: 12px;
  letter-spacing: 0.04em;
  margin: 0 0 14px;
}
.site-updated time { font-variant-numeric: tabular-nums; }
.eyebrow {
  color: var(--accent); font-size: 11.5px; letter-spacing: 0.22em;
  text-transform: uppercase; font-weight: 600;
  margin-bottom: 16px;
  display: flex; align-items: center; gap: 10px;
}
.eyebrow .lecture-num {
  background: var(--accent-soft);
  border: 1px solid var(--accent-line);
  padding: 3px 9px; border-radius: 100px;
  letter-spacing: 0.12em; font-size: 11px;
}
.hero h1 {
  font-family: var(--serif);
  font-size: 48px; line-height: 1.1;
  margin: 0; letter-spacing: -0.015em;
  font-weight: 600;
}
.hero .lede {
  color: var(--text-dim);
  font-size: 18px; line-height: 1.6;
  margin: 20px 0 0;
  max-width: 62ch;
}

/* ============== SECTIONS / HEADINGS ============== */
section { margin-top: 64px; scroll-margin-top: 84px; }
section:first-of-type { margin-top: 48px; }

h2 {
  font-family: var(--serif);
  font-size: 30px; line-height: 1.2;
  margin: 0 0 18px;
  letter-spacing: -0.01em;
  font-weight: 600;
  scroll-margin-top: 84px;
}
h2 .section-num {
  display: inline-block;
  color: var(--text-muted);
  font-size: 14px; font-weight: 500;
  margin-right: 14px;
  font-family: var(--sans);
  letter-spacing: 0;
  vertical-align: middle;
  transform: translateY(-2px);
}

h3 {
  font-size: 19px;
  margin: 32px 0 8px;
  font-weight: 600;
  color: var(--text);
  letter-spacing: -0.005em;
}

h4 {
  font-size: 15px;
  margin: 22px 0 4px;
  font-weight: 600;
  color: var(--text-dim);
  letter-spacing: 0.03em;
  text-transform: uppercase;
}

/* ============== PROSE ============== */
p { margin: 14px 0; }
p b, p strong { color: var(--text); font-weight: 600; }
p em, p i { color: var(--text); font-style: italic; }

ul, ol { margin: 14px 0; padding-left: 22px; }
li { margin: 6px 0; }
li::marker { color: var(--accent); }

a {
  color: var(--accent);
  text-decoration: none;
  border-bottom: 1px solid rgba(111,177,255,0.25);
  transition: border-color 0.2s;
}
a:hover { border-color: var(--accent); }

abbr { border-bottom: 1px dotted var(--text-muted); cursor: help; }
code { font-family: var(--mono); font-size: 0.92em; background: var(--gray-soft); padding: 1px 5px; border-radius: 4px; }

/* small dropcap-ish first letter of section lede */
.section-lede {
  color: var(--text-dim);
  font-size: 16px; line-height: 1.62;
  margin: 0 0 20px;
  max-width: 62ch;
}

/* ============== CALLOUTS (used SPARINGLY) ============== */
.callout {
  border-radius: 12px;
  padding: 16px 20px;
  margin: 22px 0;
  position: relative;
  border: 1px solid;
  background: var(--bg-soft);
  font-size: 16px;
}
.callout p { margin: 0; }
.callout p + p { margin-top: 8px; }
.callout .label {
  font-size: 11px; letter-spacing: 0.18em;
  text-transform: uppercase; font-weight: 700;
  margin-bottom: 10px;
  display: flex; align-items: center; gap: 8px;
}
.callout .label span:first-child {
  font-size: 12px;
}

/* RSV — главное: вопрос Росавиации */
.callout.rsv {
  background: var(--danger-soft);
  border-color: var(--danger-line);
}
.callout.rsv .label { color: var(--danger); }
.callout.rsv .label::before {
  content: "✈"; font-size: 14px;
}

/* WARN — безопасность */
.callout.warn {
  background: var(--warn-soft);
  border-color: var(--warn-line);
}
.callout.warn .label { color: var(--warn); }
.callout.warn .label::before {
  content: "⚠"; font-size: 14px;
}

/* NOTE — пояснение / контекст */
.callout.note {
  background: var(--accent-soft);
  border-color: var(--accent-line);
}
.callout.note .label { color: var(--accent); }

/* UNSURE — преподаватель не уверен */
.callout.unsure {
  background: var(--gray-soft);
  border-color: var(--gray-line);
  color: var(--text-dim);
}
.callout.unsure .label { color: var(--text-muted); }
.callout.unsure b { color: var(--text); }

/* ============== TERMS ============== */
.term {
  background: linear-gradient(180deg, var(--term-soft), transparent 90%), var(--bg-card);
  border: 1px solid var(--term-line);
  border-radius: 14px;
  padding: 18px 22px;
  margin: 24px 0;
  font-size: 16px;
}
.term .term-label {
  color: var(--term);
  font-size: 11px; letter-spacing: 0.18em;
  text-transform: uppercase; font-weight: 700;
  margin: 0 0 8px;
  display: flex; align-items: center; gap: 8px;
}
.term .term-label::before { content: "📖"; font-size: 13px; }
.term .term-title {
  font-size: 18px; font-weight: 600;
  margin: 0 0 10px;
  letter-spacing: -0.005em;
}
.term p { margin: 8px 0; }
.term p:last-child { margin-bottom: 0; }
.term dl {
  margin: 6px 0 0;
  display: grid; grid-template-columns: max-content 1fr;
  column-gap: 18px; row-gap: 8px;
}
.term dt { font-weight: 600; color: var(--text); }
.term dd { margin: 0; color: var(--text-dim); }

/* ============== INLINE NUMBERS / FACTS ============== */
.nums {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
  gap: 10px;
  margin: 20px 0;
}
.num {
  background: var(--bg-card);
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 14px 16px;
}
.num .big {
  font-family: var(--serif);
  font-size: 26px;
  font-weight: 700;
  color: var(--accent);
  letter-spacing: -0.01em;
  line-height: 1.1;
}
.num .lbl {
  color: var(--text-dim);
  font-size: 13px; line-height: 1.45;
  margin-top: 6px;
}

/* ============== QUOTE / PULL-QUOTE ============== */
.quote {
  border-left: 2px solid var(--accent);
  padding: 4px 0 4px 20px;
  margin: 24px 0;
  color: var(--text-dim);
  font-family: var(--serif);
  font-size: 18px;
  line-height: 1.55;
  font-style: italic;
}
.quote b { color: var(--text); font-style: normal; font-weight: 600; }

/* ============== FIGURES (placeholder for future slides) ============== */
.figure {
  margin: 30px 0;
  border: 1px dashed var(--line);
  border-radius: 12px;
  padding: 18px;
  text-align: center;
  color: var(--text-muted);
  font-size: 13px;
}
.figure img { max-width: 100%; height: auto; border-radius: 8px; display: block; margin: 0 auto; }
.figure figcaption { margin-top: 10px; font-size: 13px; color: var(--text-dim); }

/* ============== DIAGRAM (инлайновые SVG-схемы) ============== */
.diagram {
  margin: 28px 0;
  padding: 18px 18px 14px;
  background: var(--bg-card);
  border: 1px solid var(--line);
  border-radius: 14px;
}
.diagram .d-title {
  font-size: 12px; letter-spacing: 0.1em; text-transform: uppercase;
  color: var(--text-dim); font-weight: 600; margin-bottom: 14px;
}
.diagram svg { width: 100%; height: auto; display: block; }
.diagram figcaption {
  margin-top: 12px; font-size: 14px; line-height: 1.6;
  color: var(--text-dim); text-align: left;
}
.diagram figcaption b { color: var(--text); font-weight: 600; }

/* типографика внутри схем */
.diagram svg text { font-family: var(--sans); font-size: 13px; fill: var(--text); }
.diagram svg .t-lbl { font-size: 12px; fill: var(--text-dim); }
.diagram svg .t-sm  { font-size: 11px; fill: var(--text-muted); }
.diagram svg .t-hi  { font-weight: 600; }
.diagram svg .t-num { font-family: var(--serif); font-size: 16px; font-weight: 700; fill: var(--accent); }
.diagram svg .t-acc { fill: var(--accent); }
.diagram svg .t-warn { fill: var(--warn); }
.diagram svg .t-dng { fill: var(--danger); }
.diagram svg .t-trm { fill: var(--term); }
.diagram svg .mid { text-anchor: middle; }
.diagram svg .end { text-anchor: end; }

/* блоки и линии */
.diagram svg .box   { fill: var(--bg-card-2); stroke: var(--line); stroke-width: 1; }
.diagram svg .box-a { fill: var(--accent-soft); stroke: var(--accent-line); stroke-width: 1; }
.diagram svg .box-w { fill: var(--warn-soft);   stroke: var(--warn-line);   stroke-width: 1; }
.diagram svg .box-d { fill: var(--danger-soft); stroke: var(--danger-line); stroke-width: 1; }
.diagram svg .box-t { fill: var(--term-soft);   stroke: var(--term-line);   stroke-width: 1; }
.diagram svg .ln    { stroke: var(--line);   stroke-width: 1;   fill: none; }
.diagram svg .ln-a  { stroke: var(--accent); stroke-width: 1.5; fill: none; }
.diagram svg .ln-w  { stroke: var(--warn);   stroke-width: 1.5; fill: none; }
.diagram svg .ln-t  { stroke: var(--term);   stroke-width: 1.5; fill: none; }
.diagram svg .ln-dim { stroke: var(--text-muted); stroke-width: 1; fill: none; }
.diagram svg .rw-strip { stroke: var(--text-dim); stroke-width: 14; fill: none; }
.diagram svg .rw-line  { stroke: var(--text-dim); stroke-width: 5;  fill: none; }
.diagram svg .rw-axis  { stroke: var(--bg-card); stroke-width: 1.5; stroke-dasharray: 9 7; fill: none; }
.diagram svg .dash  { stroke-dasharray: 5 5; }
.diagram svg .fill-a { fill: var(--accent); stroke: none; }
.diagram svg .fill-w { fill: var(--warn);   stroke: none; }
.diagram svg .fill-dim { fill: var(--text-muted); stroke: none; }
.diagram svg .ln-d   { stroke: var(--danger); stroke-width: 1.5; fill: none; }
.diagram svg .fill-d { fill: var(--danger); stroke: none; }

/* огни ВПП */
.diagram svg .lt-white { fill: #e6edf3; stroke: none; }
.diagram svg .lt-green { fill: #5ed99a; stroke: none; }
.diagram svg .lt-red   { fill: #ff7b7b; stroke: none; }

/* ============== TABLE (когда правда нужно сравнить) ============== */
.compare {
  width: 100%;
  border-collapse: collapse;
  margin: 20px 0;
  font-size: 15.5px;
}
.compare th, .compare td {
  padding: 12px 14px;
  border-bottom: 1px solid var(--line);
  text-align: left;
  vertical-align: top;
}
.compare th {
  font-size: 12px; letter-spacing: 0.1em; text-transform: uppercase;
  color: var(--text-dim);
  font-weight: 600;
}
.compare tr:last-child td { border-bottom: none; }
.compare td b { color: var(--text); }

/* ============== STEP-BY-STEP PROCEDURE ============== */
.steps {
  counter-reset: step;
  list-style: none;
  padding: 0;
  margin: 20px 0;
}
.steps > li {
  counter-increment: step;
  position: relative;
  padding: 6px 0 6px 44px;
  margin: 12px 0;
}
.steps > li::before {
  content: counter(step);
  position: absolute;
  left: 0; top: 4px;
  width: 30px; height: 30px;
  border-radius: 50%;
  background: var(--bg-card);
  border: 1px solid var(--line);
  color: var(--accent);
  font-weight: 700;
  font-size: 14px;
  display: flex; align-items: center; justify-content: center;
  font-family: var(--sans);
}

/* ============== LECTURE FOOTER NAV (prev/next) ============== */
.lecture-nav {
  margin-top: 96px;
  padding-top: 24px;
  border-top: 1px solid var(--line);
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
}
.lecture-nav a {
  border: 1px solid var(--line);
  border-radius: 14px;
  padding: 16px 18px;
  text-decoration: none;
  background: var(--bg-card);
  color: var(--text);
  transition: border-color 0.2s, background 0.2s, transform 0.2s;
}
.lecture-nav a:hover {
  border-color: var(--accent-line);
  background: var(--bg-card-2);
  transform: translateY(-2px);
}
.lecture-nav .direction {
  font-size: 11px; letter-spacing: 0.18em; text-transform: uppercase;
  color: var(--text-dim);
  margin-bottom: 6px;
}
.lecture-nav .title {
  font-size: 16px;
  font-weight: 600;
  line-height: 1.3;
}
.lecture-nav .next { text-align: right; }
.lecture-nav .placeholder {
  border: 1px dashed var(--line);
  border-radius: 14px;
  padding: 16px 18px;
  color: var(--text-muted);
  font-size: 13px;
}

/* ============== INDEX-PAGE SPECIFIC ============== */
.toc-section { margin-top: 56px; }
.toc-heading {
  font-size: 12px; letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--text-dim);
  font-weight: 600;
  margin-bottom: 6px;
}
.toc-sub {
  margin: 0 0 24px;
  color: var(--text-dim);
  font-size: 14.5px;
  max-width: 60ch;
}

.lecture-card {
  display: grid;
  grid-template-columns: 60px 1fr auto;
  gap: 20px;
  align-items: center;
  text-decoration: none;
  color: inherit;
  padding: 22px 24px;
  background: var(--bg-card);
  border: 1px solid var(--line);
  border-radius: 16px;
  margin-bottom: 12px;
  transition: border-color 0.2s, background 0.2s, transform 0.2s;
}
.lecture-card:hover {
  border-color: var(--accent-line);
  background: var(--bg-card-2);
  transform: translateY(-2px);
}
.lecture-card .num-large {
  font-family: var(--serif);
  font-size: 38px;
  font-weight: 700;
  color: var(--accent);
  line-height: 1;
  letter-spacing: -0.02em;
}
.lecture-card .num-large.abbr {
  font-size: 27px;
  letter-spacing: 0.01em;
  padding-top: 4px;
}
.lecture-card .card-icon {
  display: grid;
  place-items: center;
  width: 52px;
  height: 52px;
  border: 1px solid var(--accent-line);
  border-radius: 13px;
  background: var(--accent-soft);
  color: var(--accent);
  transition: border-color 0.2s, background 0.2s;
}
.lecture-card .card-icon svg {
  width: 27px;
  height: 27px;
  display: block;
}
.lecture-card:hover .card-icon {
  border-color: var(--accent);
}
.lecture-card h2 {
  font-family: var(--serif);
  font-size: 21px;
  margin: 0 0 7px;
  font-weight: 600;
  letter-spacing: -0.005em;
  line-height: 1.25;
  color: var(--text);
}
.lecture-card .desc {
  margin: 0;
  color: var(--text-dim);
  font-size: 14.5px;
  line-height: 1.55;
}
.lecture-card .card-meta {
  margin: 0;
  font-size: 12px;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--text-muted);
  font-weight: 600;
}
.lecture-card .card-meta b {
  color: var(--accent);
  font-weight: 600;
}
.lecture-card .arrow {
  align-self: center;
  color: var(--text-muted);
  font-size: 24px;
  transition: transform 0.2s, color 0.2s;
}
.lecture-card:hover .arrow { color: var(--accent); transform: translateX(4px); }

.rsv-aggregate {
  margin-top: 56px;
  background: var(--danger-soft);
  border: 1px solid var(--danger-line);
  border-radius: 16px;
  padding: 22px 24px;
  display: block;
  text-decoration: none;
  color: inherit;
  transition: border-color 0.2s, transform 0.2s;
}
.rsv-aggregate:hover {
  border-color: var(--danger);
  transform: translateY(-2px);
}
.rsv-aggregate .label {
  color: var(--danger);
  font-size: 11px; letter-spacing: 0.18em; text-transform: uppercase;
  font-weight: 700;
  margin-bottom: 8px;
  display: flex; align-items: center; gap: 8px;
}
.rsv-aggregate .label::before { content: "✈"; }
.rsv-aggregate h2 {
  font-family: var(--serif);
  font-size: 22px;
  font-weight: 600;
  margin: 0 0 6px;
  color: var(--text);
  letter-spacing: -0.005em;
}
.rsv-aggregate p {
  margin: 0;
  color: var(--text-dim);
  font-size: 14.5px;
}

/* ============== RSV AGGREGATE PAGE ============== */
.rsv-group { margin-top: 56px; }
.rsv-group:first-of-type { margin-top: 40px; }
.rsv-group-link {
  display: grid;
  grid-template-columns: 1fr auto;
  align-items: center;
  text-decoration: none;
  color: inherit;
  background: var(--bg-card);
  border: 1px solid var(--line);
  border-radius: 14px;
  padding: 18px 22px;
  margin-bottom: 18px;
  transition: border-color 0.2s, background 0.2s, transform 0.2s;
}
.rsv-group-link:hover {
  border-color: var(--danger-line);
  background: var(--bg-card-2);
  transform: translateY(-2px);
}
.rsv-group-eyebrow {
  color: var(--danger);
  font-size: 11px; letter-spacing: 0.18em;
  text-transform: uppercase;
  font-weight: 700;
  margin-bottom: 4px;
}
.rsv-group-title {
  font-family: var(--serif);
  font-size: 22px;
  font-weight: 600;
  margin: 0;
  letter-spacing: -0.005em;
  color: var(--text);
  line-height: 1.25;
}
.rsv-subhead {
  margin: 26px 0 12px;
  font-size: 13px;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--text-muted);
}
.rsv-subhead:first-of-type { margin-top: 18px; }
.rsv-group-cta {
  color: var(--text-dim);
  font-size: 13px;
  letter-spacing: 0.02em;
}
.rsv-group-link:hover .rsv-group-cta { color: var(--danger); }

.rsv-group .callout.rsv { margin: 10px 0; }

/* ============== REVEAL ANIMATION ============== */
.reveal {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.7s cubic-bezier(0.22, 1, 0.36, 1),
              transform 0.7s cubic-bezier(0.22, 1, 0.36, 1);
  will-change: opacity, transform;
}
.reveal.visible { opacity: 1; transform: translateY(0); }

@media (prefers-reduced-motion: reduce) {
  .reveal { opacity: 1; transform: none; transition: none; }
}

/* ============== MOBILE ============== */
@media (max-width: 720px) {
  .wrap { padding: 18px 18px 64px; }
  .diagram { padding: 12px 10px 10px; border-radius: 12px; }
  .diagram figcaption { font-size: 13px; }
  /* на узком экране подписи в SVG становятся нечитаемыми — даём горизонтальный скролл */
  .diagram { overflow-x: auto; -webkit-overflow-scrolling: touch; }
  .diagram svg { min-width: 620px; }
  .site-header-inner { padding: 10px 16px; }
  .search-input { font-size: 14px; padding: 9px 12px 9px 34px; background-position: 11px center; }
  .hero h1 { font-size: 36px; }
  .hero .lede { font-size: 16.5px; }
  h2 { font-size: 24px; }
  h3 { font-size: 17px; }
  body { font-size: 16.5px; }
  .lecture-nav { grid-template-columns: 1fr; }
  .lecture-nav .next { text-align: left; }
  .term dl { grid-template-columns: 1fr; row-gap: 2px; }
  .term dt { margin-top: 6px; }
  .lecture-card { grid-template-columns: 1fr; gap: 8px; padding: 18px 20px; }
  .lecture-card .num-large { font-size: 28px; }
  .lecture-card .arrow { display: none; }
  .nums { grid-template-columns: 1fr 1fr; gap: 8px; }
  .num .big { font-size: 22px; }
}

@media (max-width: 560px) {
  .lecture-card { grid-template-columns: 46px 1fr auto; gap: 14px; padding: 18px 16px; }
  .lecture-card .card-icon { width: 46px; height: 46px; border-radius: 12px; }
  .lecture-card .card-icon svg { width: 24px; height: 24px; }
}