/* Олімпіада з фізики — спільні стилі. Mobile-first. */

@font-face {
  font-family: 'Golos Text';
  font-style: normal;
  font-display: swap;
  font-weight: 400 900;
  src: url(fonts/golos-text-cyrillic-wght-normal.woff2) format('woff2-variations'), url(fonts/golos-text-cyrillic-wght-normal.woff2) format('woff2');
  unicode-range: U+0301, U+0400-045F, U+0490-0491, U+04B0-04B1, U+2116;
}
@font-face {
  font-family: 'Golos Text';
  font-style: normal;
  font-display: swap;
  font-weight: 400 900;
  src: url(fonts/golos-text-latin-wght-normal.woff2) format('woff2-variations'), url(fonts/golos-text-latin-wght-normal.woff2) format('woff2');
  unicode-range: U+0000-00FF, U+0131, U+0152-0153, U+02BB-02BC, U+02C6, U+02DA, U+02DC, U+0304, U+0308, U+0329, U+2000-206F, U+20AC, U+2122, U+2191, U+2193, U+2212, U+2215, U+FEFF, U+FFFD;
}

/* ---------- кольори ---------- */
:root {
  --bg: #f6f7f9;
  --surface: #ffffff;
  --surface-2: #f1f3f7;
  --text: #1b2230;
  --muted: #586174;
  --border: #dfe3ea;
  --shadow: 0 1px 2px rgb(16 24 40 / .05), 0 2px 8px rgb(16 24 40 / .05);

  --cond-bg: #eef3fa;
  --cond-line: #6d8fbd;

  --step: #3451c6;          /* акцент кроків */
  --step-soft: #e9edfc;
  --step-on: #ffffff;

  --answer: #17703f;        /* акцент відповіді */
  --answer-bg: #e6f5ec;
  --answer-line: #2f9a5d;

  --warn: #8a5300;
  --warn-bg: #fff4de;
  --warn-line: #d99012;

  --formula-bg: #f5f7fc;
  --figure-bg: #ffffff;

  --tag-mech: #1f5fbf;  --tag-mech-bg: #e5eefc;
  --tag-hydro: #0b6f80; --tag-hydro-bg: #e0f4f6;
  --tag-heat: #b23b10;  --tag-heat-bg: #fdebe2;
  --tag-elec: #7a3fbf;  --tag-elec-bg: #f1e8fc;
  --tag-opt: #9a5a00;   --tag-opt-bg: #fcf1dc;
  --tag-mol: #3d6b1f;   --tag-mol-bg: #e8f3df;

  --radius: 14px;
  --radius-s: 9px;
  --toc-h: 3.4rem;
  color-scheme: light;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #11151c;
    --surface: #181d26;
    --surface-2: #202633;
    --text: #e7eaf0;
    --muted: #a6afbf;
    --border: #2c3443;
    --shadow: none;

    --cond-bg: #1b2433;
    --cond-line: #6f8fc4;

    --step: #93a8ff;
    --step-soft: #232c49;
    --step-on: #10152a;

    --answer: #74d79c;
    --answer-bg: #142a1e;
    --answer-line: #3aa86a;

    --warn: #f2c46d;
    --warn-bg: #2a2113;
    --warn-line: #c98a1a;

    --formula-bg: #1c2230;
    --figure-bg: #fbfbfd;

    --tag-mech: #9cc0ff;  --tag-mech-bg: #1c2a44;
    --tag-hydro: #7fd6e2; --tag-hydro-bg: #12313a;
    --tag-heat: #ffab88;  --tag-heat-bg: #3a2016;
    --tag-elec: #d1aefc;  --tag-elec-bg: #2c2040;
    --tag-opt: #f4c56f;   --tag-opt-bg: #352712;
    --tag-mol: #b4dd8e;   --tag-mol-bg: #22301a;
    color-scheme: dark;
  }
}

/* ---------- база ---------- */
*, *::before, *::after { box-sizing: border-box; }
html {
  font-size: 106.25%; /* 17px */
  -webkit-text-size-adjust: 100%;
  text-size-adjust: 100%;
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--toc-h) + .75rem);
}
@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } }
@media (min-width: 768px) { html { font-size: 112.5%; } } /* 18px */
@media (min-width: 1100px) { html { scroll-padding-top: 1.25rem; } }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: 'Golos Text', system-ui, -apple-system, 'Segoe UI', Roboto, Arial, sans-serif;
  line-height: 1.6;
  overflow-wrap: break-word;
}
a { color: var(--step); text-underline-offset: .18em; }
h1, h2, h3, h4 { line-height: 1.25; text-wrap: balance; }
p { margin: .6em 0; }
ul, ol { padding-left: 1.3em; margin: .5em 0; }
li { margin: .3em 0; }
li::marker { color: var(--muted); }
b, strong { font-weight: 650; }
table { border-collapse: collapse; }
:focus-visible { outline: 3px solid var(--step); outline-offset: 2px; border-radius: 4px; }
.sr-only { position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; }
.js-only { display: none !important; }
.js .js-only { display: revert !important; }
.js .toggle.js-only { display: inline-flex !important; }

.skip { position: absolute; left: .5rem; top: -3rem; z-index: 50; background: var(--surface); padding: .5rem .8rem; border-radius: var(--radius-s); }
.skip:focus { top: .5rem; }

/* ---------- шапка ---------- */
.site-head {
  padding: 1.1rem 1rem 1.2rem;
  max-width: 44rem;
  margin: 0 auto;
}
.back {
  display: inline-block;
  font-weight: 600;
  text-decoration: none;
  padding: .35rem .7rem;
  margin-left: -.7rem;
  border-radius: 99px;
}
.back:hover { background: var(--step-soft); }
.site-head__title { font-size: 1.55rem; margin: .5rem 0 .15rem; letter-spacing: -.01em; }
.site-head__sub { margin: 0; color: var(--muted); font-weight: 600; }
.site-head__lead { margin: .5rem 0 0; color: var(--muted); font-size: .95rem; }

/* ---------- макет ---------- */
.layout { max-width: 76rem; margin: 0 auto; }
.main { padding: 0 .75rem 2rem; min-width: 0; }

/* ---------- навігація (мобільна: липка смуга чипів) ---------- */
.toc {
  position: sticky;
  top: 0;
  z-index: 20;
  display: flex;
  align-items: center;
  gap: .5rem;
  height: var(--toc-h);
  padding: 0 .5rem 0 0;
  background: color-mix(in srgb, var(--bg) 88%, transparent);
  -webkit-backdrop-filter: saturate(1.4) blur(10px);
  backdrop-filter: saturate(1.4) blur(10px);
  border-bottom: 1px solid var(--border);
}
.toc__list {
  display: flex;
  gap: .4rem;
  list-style: none;
  margin: 0;
  padding: 0 .75rem;
  overflow-x: auto;
  scrollbar-width: none;
  flex: 1;
  min-width: 0;
  scroll-padding-inline: .75rem;
}
.toc__list::-webkit-scrollbar { display: none; }
.toc__list li { margin: 0; flex: none; }
.toc__link {
  display: block;
  padding: .38rem .8rem;
  border-radius: 99px;
  border: 1px solid var(--border);
  background: var(--surface);
  color: var(--text);
  text-decoration: none;
  font-weight: 600;
  font-size: .9rem;
  white-space: nowrap;
}
.toc__name { display: none; }
.toc__word { display: none; }
.toc__list li:first-child .toc__word { display: inline; }
.toc__link { min-width: 2.5rem; text-align: center; }
.toc__link[aria-current="true"] { background: var(--step); border-color: var(--step); color: var(--step-on); }

/* перемикач самоперевірки */
.toggle {
  flex: none;
  display: inline-flex;
  align-items: center;
  gap: .45rem;
  border: 1px solid var(--border);
  background: var(--surface);
  color: var(--text);
  font: inherit;
  font-size: .85rem;
  font-weight: 600;
  padding: .35rem .6rem;
  border-radius: 99px;
  cursor: pointer;
  line-height: 1.2;
}
.toggle__track {
  position: relative;
  width: 2.1rem;
  height: 1.2rem;
  border-radius: 99px;
  background: var(--border);
  transition: background .15s;
  flex: none;
}
.toggle__track::after {
  content: '';
  position: absolute;
  top: .15rem;
  left: .15rem;
  width: .9rem;
  height: .9rem;
  border-radius: 50%;
  background: var(--surface);
  box-shadow: 0 1px 2px rgb(0 0 0 / .3);
  transition: transform .15s;
}
.toggle[aria-pressed="true"] .toggle__track { background: var(--step); }
.toggle[aria-pressed="true"] .toggle__track::after { transform: translateX(.9rem); }
@media (max-width: 480px) {
  .toggle__text { position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0 0 0 0); }
  .toggle { padding: .45rem .5rem; }
}

/* ---------- десктоп: бічна панель ---------- */
@media (min-width: 1100px) {
  .layout {
    display: grid;
    grid-template-columns: 16rem minmax(0, 1fr);
    gap: 2rem;
    padding: 0 1.5rem;
  }
  .site-head { max-width: 76rem; padding: 1.5rem 1.5rem 1.5rem calc(16rem + 3.5rem); }
  .toc {
    top: 1rem;
    align-self: start;
    flex-direction: column;
    align-items: stretch;
    height: auto;
    max-height: calc(100vh - 2rem);
    padding: .5rem;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    -webkit-backdrop-filter: none;
    backdrop-filter: none;
    box-shadow: var(--shadow);
    margin-top: .25rem;
  }
  .toc__list { flex-direction: column; overflow: auto; padding: 0; gap: .15rem; }
  .toc__link {
    display: grid;
    gap: .05rem;
    border: 0;
    border-radius: var(--radius-s);
    white-space: normal;
    padding: .5rem .7rem;
    background: transparent;
    border-left: 3px solid transparent;
  }
  .toc__link:hover { background: var(--surface-2); }
  .toc__no { font-size: .78rem; color: var(--muted); font-weight: 600; }
  .toc__word, .toc__list li:first-child .toc__word { display: inline; }
  .toc__link { text-align: left; }
  .toc__name { display: block; font-size: .9rem; font-weight: 600; line-height: 1.35; }
  .toc__link[aria-current="true"] { background: var(--step-soft); color: var(--text); border-left-color: var(--step); }
  .toc__link[aria-current="true"] .toc__no { color: var(--step); }
  .toggle { margin: .5rem .2rem .2rem; justify-content: flex-start; border-radius: var(--radius-s); padding: .55rem .7rem; }
  .main { padding: 0 0 3rem; }
}

/* ---------- огляд ---------- */
.overview, .task {
  max-width: 44rem;
  margin: 1rem auto 0;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}
.overview { padding: 1rem 1rem .6rem; }
.overview__title { font-size: 1.1rem; margin: 0 0 .5rem; }
.overview__list { list-style: none; padding: 0; margin: 0; }
.overview__row {
  display: grid;
  grid-template-columns: 2.2rem 1fr;
  column-gap: .6rem;
  padding: .55rem 0;
  margin: 0;
  border-top: 1px solid var(--border);
  align-items: baseline;
}
.overview__row:first-child { border-top: 0; }
.overview__no {
  grid-row: span 2;
  display: grid;
  place-items: center;
  width: 2rem;
  height: 2rem;
  border-radius: 50%;
  background: var(--step-soft);
  color: var(--step);
  font-weight: 700;
  text-decoration: none;
  align-self: start;
}
.overview__topic { font-weight: 600; }
.overview__ans { color: var(--answer); font-size: .92rem; }
.overview__hint { font-size: .85rem; color: var(--muted); margin: .6rem 0 .3rem; }
@media (min-width: 640px) {
  .overview__row { grid-template-columns: 2.2rem minmax(0, 1fr) minmax(0, 1fr); }
  .overview__no { grid-row: auto; }
  .overview__ans { text-align: right; }
}

/* ---------- задача ---------- */
.task { padding: 1.1rem 1rem 1.25rem; margin-top: 1.25rem; }
.task > * + * { margin-top: 1rem; }
@media (min-width: 768px) { .task { padding: 1.6rem 1.75rem 1.75rem; } .overview { padding: 1.2rem 1.75rem .8rem; } }

.task__meta { display: flex; flex-wrap: wrap; align-items: center; gap: .4rem .6rem; }
.task__no { font-weight: 700; color: var(--step); font-size: .9rem; letter-spacing: .02em; text-transform: uppercase; }
.task__title { font-size: 1.4rem; margin: .35rem 0 .2rem; letter-spacing: -.01em; }
.tag {
  display: inline-block;
  padding: .1rem .55rem;
  border-radius: 99px;
  font-size: .8rem;
  font-weight: 650;
  line-height: 1.5;
}
.tag--mech { color: var(--tag-mech); background: var(--tag-mech-bg); }
.tag--hydro { color: var(--tag-hydro); background: var(--tag-hydro-bg); }
.tag--heat { color: var(--tag-heat); background: var(--tag-heat-bg); }
.tag--elec { color: var(--tag-elec); background: var(--tag-elec-bg); }
.tag--opt { color: var(--tag-opt); background: var(--tag-opt-bg); }
.tag--mol { color: var(--tag-mol); background: var(--tag-mol-bg); }
.level { color: var(--muted); font-size: .8rem; letter-spacing: .12em; }

.passport { margin: .45rem 0 0; font-size: .88rem; color: var(--muted); }
.passport > summary { cursor: pointer; font-weight: 600; width: max-content; max-width: 100%; }
.passport > summary:hover { color: var(--step); }
.passport dl { margin: .4rem 0 0; display: grid; gap: .15rem; padding: .6rem .8rem; background: var(--surface-2); border-radius: var(--radius-s); }
.passport__row { display: grid; grid-template-columns: 1fr; }
.passport dt { font-weight: 650; color: var(--text); font-size: .8rem; }
.passport dd { margin: 0 0 .25rem; }
@media (min-width: 560px) {
  .passport__row { grid-template-columns: 9.5rem 1fr; gap: .75rem; }
  .passport dt { font-size: .88rem; }
}

/* умова */
.cond {
  background: var(--cond-bg);
  border-left: 4px solid var(--cond-line);
  border-radius: var(--radius-s);
  padding: .8rem 1rem .9rem;
  font-size: 1.02rem;
}
.cond__label, .given__label, .answer__label, .figure__title {
  font-size: .75rem;
  font-weight: 700;
  letter-spacing: .08em;
  text-transform: uppercase;
  color: var(--muted);
  margin-bottom: .3rem;
}
.cond-note { font-size: .9rem; color: var(--muted); padding: 0 .25rem; }

/* дано / знайти */
.given {
  display: grid;
  gap: .75rem;
  border: 1px solid var(--border);
  border-radius: var(--radius-s);
  padding: .8rem 1rem;
}
@media (min-width: 560px) { .given { grid-template-columns: minmax(0, 3fr) minmax(0, 2fr); column-gap: 1.25rem; } }
.given__col { min-width: 0; }
.given__col--find { border-top: 1px dashed var(--border); padding-top: .6rem; }
@media (min-width: 560px) { .given__col--find { border-top: 0; padding-top: 0; border-left: 1px dashed var(--border); padding-left: 1.25rem; } }
.given__table { width: 100%; font-size: .95rem; }
.given__table th { text-align: left; font-size: .75rem; font-weight: 650; color: var(--muted); padding: 0 0 .2rem; }
.given__table td { padding: .28rem 0; vertical-align: top; border-top: 1px solid var(--border); }
.given__table tbody tr:first-child td { border-top: 0; }
.given__si { color: var(--muted); padding-left: .9rem !important; white-space: nowrap; }
.given__find { font-weight: 600; }
.given__note { grid-column: 1 / -1; font-size: .88rem; color: var(--muted); border-top: 1px solid var(--border); padding-top: .2rem; }
.given__note p { margin: .4rem 0; }

/* кнопка «показати розв'язок» */
.reveal { display: none; }
.btn {
  font: inherit;
  font-weight: 650;
  border: 1.5px solid var(--step);
  color: var(--step);
  background: var(--surface);
  border-radius: 99px;
  padding: .5rem 1.1rem;
  cursor: pointer;
}
.btn:hover { background: var(--step-soft); }

/* рисунок */
.figure { margin: 1rem 0 0; }
.figure__canvas {
  background: var(--figure-bg);
  border: 1px solid var(--border);
  border-radius: var(--radius-s);
  padding: .5rem;
  margin: .4rem 0;
  overflow-x: auto;
  cursor: zoom-in;
  color-scheme: light;
}
.figure__canvas svg { display: block; overflow: visible; width: 100%; height: auto; max-width: 620px; margin: 0 auto; }
.figure__canvas.is-zoomed { cursor: zoom-out; }
.figure__canvas.is-zoomed svg { width: 760px; max-width: none; }
.figure__note { font-size: .9rem; color: var(--muted); }

/* блоки */
.block {
  border-top: 1px solid var(--border);
  padding-top: .9rem;
}
.block__title {
  font-size: 1.02rem;
  margin: 0 0 .3rem;
  display: flex;
  align-items: center;
  gap: .5rem;
}
.block__title::before {
  content: '';
  width: .55rem;
  height: .55rem;
  border-radius: 2px;
  background: var(--muted);
  flex: none;
}
.block--analysis .block__title::before { background: var(--cond-line); }
.block--check .block__title::before { background: var(--answer-line); }
.block--scen .block__title::before { background: var(--step); }
.block > p:last-child { margin-bottom: 0; }

.block--check ul { list-style: none; padding-left: 0; }
.block--check li { padding-left: 1.6rem; position: relative; }
.block--check li::before {
  content: '';
  position: absolute;
  left: .15rem;
  top: .5em;
  width: .8rem;
  height: .45rem;
  border-left: 2.5px solid var(--answer-line);
  border-bottom: 2.5px solid var(--answer-line);
  transform: rotate(-45deg);
}

.block--mistakes {
  border: 0;
  background: var(--warn-bg);
  border-left: 4px solid var(--warn-line);
  border-radius: var(--radius-s);
  padding: .8rem 1rem;
}
.block--mistakes .block__title { color: var(--warn); }
.block--mistakes .block__title::before { background: var(--warn-line); border-radius: 50%; }

details.block--teach { padding-top: .9rem; }
details.block--teach > summary { cursor: pointer; list-style: none; margin: 0; }
details.block--teach > summary::-webkit-details-marker { display: none; }
details.block--teach > summary::after { content: '▾'; margin-left: auto; color: var(--muted); transition: transform .15s; }
details.block--teach[open] > summary::after { transform: rotate(180deg); }
details.block--teach > summary::before { background: var(--tag-elec); }

.block--similar {
  border: 1px dashed var(--border);
  border-radius: var(--radius-s);
  padding: .8rem 1rem;
}
.spoiler > summary { cursor: pointer; color: var(--step); font-weight: 600; font-size: .92rem; width: max-content; }
.spoiler[open] > summary { margin-bottom: .2rem; }
.spoiler p { margin: .2rem 0; font-style: italic; }

.callout {
  border-radius: var(--radius-s);
  padding: .7rem .9rem;
  margin: .7rem 0;
  font-size: .95rem;
}
.callout--warn { background: var(--warn-bg); border-left: 4px solid var(--warn-line); }

/* ---------- розв'язання ---------- */
.solution { border-top: 1px solid var(--border); padding-top: .9rem; }
.solution__title { font-size: 1.2rem; margin: 0 0 .6rem; }
.part + .part, .part + .part__title, .methods + .part, .methods + .part__title { margin-top: 1.4rem; }
.part__title { font-size: 1.05rem; margin: 0 0 .4rem; }

.method__title { font-size: 1.02rem; margin: .2rem 0 .6rem; color: var(--step); }
.methods > .method + .method { margin-top: 1.6rem; padding-top: 1.2rem; border-top: 1px dashed var(--border); }

/* вкладки (додає app.js) */
.tabs__list {
  display: flex;
  gap: .3rem;
  overflow-x: auto;
  scrollbar-width: none;
  padding: .25rem;
  margin: 0 0 .9rem;
  background: var(--surface-2);
  border-radius: 99px;
  width: max-content;
  max-width: 100%;
}
.tabs__list::-webkit-scrollbar { display: none; }
.tabs__tab {
  flex: none;
  font: inherit;
  font-size: .9rem;
  font-weight: 650;
  border: 0;
  background: transparent;
  color: var(--muted);
  padding: .4rem .95rem;
  border-radius: 99px;
  cursor: pointer;
  white-space: nowrap;
}
.tabs__tab[aria-selected="true"] { background: var(--surface); color: var(--step); box-shadow: 0 1px 3px rgb(0 0 0 / .14); }
.js .methods[data-ready] > .method[hidden] { display: none; }
.js .methods[data-ready] > .method + .method { margin-top: 0; padding-top: 0; border-top: 0; }

/* кроки */
.steps { list-style: none; padding: 0; margin: .4rem 0 0; counter-reset: none; }
.step {
  position: relative;
  margin: 0;
  padding: 0 0 1rem 1.15rem;
  border-left: 2px solid var(--step-soft);
  margin-left: .45rem;
}
.step:last-child { padding-bottom: .2rem; }
.step::before {
  content: '';
  position: absolute;
  left: -.42rem;
  top: .38rem;
  width: .7rem;
  height: .7rem;
  border-radius: 50%;
  background: var(--surface);
  border: 2.5px solid var(--step);
}
.step__head { display: flex; flex-wrap: wrap; align-items: baseline; gap: .1rem .55rem; }
.step__num {
  font-size: .75rem;
  font-weight: 750;
  letter-spacing: .06em;
  text-transform: uppercase;
  color: var(--step);
  white-space: nowrap;
}
.step__title { font-weight: 650; }
.step__body > p:first-child { margin-top: .2rem; }
.step__body > :last-child { margin-bottom: 0; }

/* формули */
.formula {
  background: var(--formula-bg);
  border-radius: var(--radius-s);
  padding: .1rem .9rem;
  margin: .5rem 0;
  overflow-x: auto;
  overflow-y: hidden;
  -webkit-overflow-scrolling: touch;
  max-width: 100%;
}
.formula .katex-display { margin: .55rem 0; }
.formula .katex-display + .katex-display { margin-top: .9rem; }
.formula .katex-display > .katex { text-align: left; padding: .1rem 0; }
.formula--key {
  background: var(--step-soft);
  box-shadow: inset 3px 0 0 var(--step);
}
.katex { font-size: 1.08em; }
.formula .katex { font-size: 1.12em; }
.prose .katex, .step__body .katex, p .katex { white-space: normal; }

/* відповідь */
.answer {
  background: var(--answer-bg);
  border: 2px solid var(--answer-line);
  border-radius: var(--radius);
  padding: .8rem 1rem .9rem;
}
.answer__label { color: var(--answer); }
.answer__body { font-weight: 650; font-size: 1.08rem; }

/* ---------- режим самоперевірки ---------- */
.selfcheck .overview [data-sol],
.selfcheck .task:not(.is-revealed) [data-sol] { display: none !important; }
.selfcheck .reveal { display: block; }

/* ---------- підвал ---------- */
.site-foot { text-align: center; color: var(--muted); padding: 1rem 1rem 2.5rem; font-size: .92rem; }

/* ---------- стартова сторінка ---------- */
.site-head--index { text-align: left; padding-top: 2rem; }
.site-head--index .site-head__title { font-size: 2rem; }
.main--index { max-width: 64rem; margin: 0 auto; padding: .5rem 1rem 2rem; }
.cards { list-style: none; padding: 0; margin: 0; display: grid; gap: 1rem; }
@media (min-width: 640px) { .cards { grid-template-columns: 1fr 1fr; } }
.card { margin: 0; }
.card__link {
  display: flex;
  flex-direction: column;
  gap: .4rem;
  height: 100%;
  padding: 1.2rem 1.25rem 1.1rem;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: calc(var(--radius) + 4px);
  box-shadow: var(--shadow);
  color: var(--text);
  text-decoration: none;
  transition: border-color .15s, transform .15s;
}
.card__link:hover { border-color: var(--step); transform: translateY(-2px); }
.card__grade { font-size: 1.35rem; font-weight: 700; }
.card__num { font-size: 2.6rem; line-height: 1; color: var(--step); margin-right: .15rem; letter-spacing: -.02em; }
.card__count { color: var(--muted); font-weight: 600; }
.card__tags { display: flex; flex-wrap: wrap; gap: .3rem; }
.card__topics { margin: .3rem 0 0; padding-left: 1.4em; font-size: .93rem; color: var(--muted); }
.card__topics li { margin: .12rem 0; }
.card__go { margin-top: auto; padding-top: .4rem; color: var(--step); font-weight: 650; }

/* ---------- друк ---------- */
@media print {
  @page { margin: 14mm 12mm; }
  html { font-size: 11pt; }
  :root {
    --bg: #fff; --surface: #fff; --text: #000; --muted: #333; --border: #bbb; --shadow: none;
    --cond-bg: #f2f5fa; --formula-bg: #f6f7fa; --step-soft: #eef1fb; --answer-bg: #eef8f1; --warn-bg: #fff7e8;
  }
  body { background: #fff; }
  .toc, .back, .skip, .site-foot, .reveal, .toggle, .overview__hint, .tabs__list { display: none !important; }
  .layout { display: block; padding: 0; }
  .site-head { padding: 0 0 6mm; max-width: none; }
  .overview, .task { max-width: none; border: 0; box-shadow: none; padding: 0; margin: 0; }
  .task { break-before: page; }
  .selfcheck .overview [data-sol], .selfcheck .task:not(.is-revealed) [data-sol] { display: revert !important; }
  .js .methods[data-ready] > .method[hidden] { display: block !important; }
  .js .methods[data-ready] > .method + .method { margin-top: 1rem; padding-top: .8rem; border-top: 1px dashed var(--border); }
  details > summary::after { display: none; }
  details::details-content { content-visibility: visible; display: contents; }
  .formula { overflow: visible; }
  .figure__canvas { break-inside: avoid; overflow: visible; }
  .figure__canvas svg, .figure__canvas.is-zoomed svg { width: 100%; max-width: 15cm; }
  .step, .answer, .formula, .given, .cond { break-inside: avoid; }
  .block__title, .method__title, .step__head, .part__title { break-after: avoid; }
  a { color: inherit; text-decoration: none; }
}

/* формули ніколи не трансформуємо */
.katex { text-transform: none; letter-spacing: normal; }