/* appliedmathlab.org. Рожево-чорне оформлення, без логотипа. */
:root {
  --ink: #1A1A1A;
  --ink-soft: #3F3A3C;
  --bg: #FFF7F9;
  --paper: #FFFFFF;
  --pink: #FFC0CB;
  --pink-soft: #FFE3E9;
  --pink-deep: #B3124F;
  --line: #F3C6D0;
  --shadow: 0 12px 30px rgba(179, 18, 79, 0.12);
  --radius: 14px;
  --max: 72rem;
  --text: 60rem;
  --gutter: 1rem;
  --font: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
}

* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }
@media (min-width: 90rem) { html { font-size: 112.5%; } }
body {
  margin: 0;
  color: var(--ink);
  font-family: var(--font);
  font-size: 1.0625rem;
  line-height: 1.6;
  background:
    radial-gradient(60rem 38rem at -10% -10%, #FFD6DF 0%, rgba(255, 214, 223, 0) 62%),
    radial-gradient(48rem 32rem at 108% 18%, #FFE4EA 0%, rgba(255, 228, 234, 0) 60%),
    var(--bg);
  min-height: 100vh;
}
::selection { background: var(--pink); color: var(--ink); }
.wrap { max-width: var(--max); margin: 0 auto; padding-left: var(--gutter); padding-right: var(--gutter); }

a { color: var(--pink-deep); }
:focus-visible { outline: 3px solid var(--pink-deep); outline-offset: 3px; border-radius: 4px; }
.sprite { display: none; }

.skip { position: absolute; left: -999px; top: .5rem; z-index: 50; background: var(--ink); color: var(--pink); padding: .5rem 1rem; border-radius: 999px; font-weight: 700; }
.skip:focus { left: var(--gutter); }

/* Шапка */
.site-header { position: sticky; top: 0; z-index: 20; background: rgba(255, 255, 255, .84); -webkit-backdrop-filter: blur(12px); backdrop-filter: blur(12px); border-bottom: 1px solid var(--line); }
.header-inner { display: flex; flex-wrap: wrap; align-items: center; gap: .5rem 1rem; padding-top: .85rem; padding-bottom: .65rem; }
.brand { position: relative; margin-right: auto; padding-left: 1.2rem; color: var(--ink); text-decoration: none; font-weight: 800; font-size: 1.15rem; letter-spacing: -.01em; }
.brand::before { content: ""; position: absolute; left: 0; top: 50%; width: .72rem; height: .72rem; border-radius: 50%; background: var(--pink); box-shadow: 0 0 0 3px var(--pink-soft); transform: translateY(-50%); transition: transform .3s; }
.brand:hover::before { transform: translateY(-50%) scale(1.25); }
.brand:hover { text-decoration: underline; text-decoration-color: var(--pink); text-decoration-thickness: 3px; text-underline-offset: .2em; }
.lang-switch { font-size: .9rem; font-weight: 600; color: var(--pink-deep); text-decoration: none; padding: .28rem .7rem; border: 1.5px solid var(--line); border-radius: 999px; background: var(--paper); transition: border-color .2s, background .2s, transform .2s; }
.lang-switch:hover { border-color: var(--pink-deep); transform: translateY(-1px); }
.site-nav { flex-basis: 100%; }
.site-nav ul { list-style: none; margin: 0; padding: 0; display: flex; flex-wrap: wrap; gap: .3rem .35rem; }
.site-nav a { display: inline-block; padding: .35rem .75rem; border-radius: 999px; color: var(--ink); text-decoration: none; font-weight: 500; transition: background .2s, color .2s, transform .2s; }
.site-nav a:hover { background: var(--pink-soft); }
.site-nav a[aria-current="page"] { background: var(--pink); font-weight: 700; }
.site-nav .button { background: var(--ink); color: var(--pink); font-weight: 700; }
.site-nav .button:hover { background: #000; color: #fff; transform: translateY(-1px); }

/* Плашка чернетки */
.notice { position: relative; z-index: 1; background: var(--ink); color: var(--pink); font-size: .92rem; }
.notice .wrap { padding-top: .5rem; padding-bottom: .5rem; }

/* Вміст */
main.wrap { position: relative; z-index: 1; padding-top: 2.5rem; padding-bottom: 4rem; }
h1 { font-size: clamp(1.9rem, 1.3rem + 2.4vw, 2.7rem); line-height: 1.12; font-weight: 800; letter-spacing: -.02em; margin: 0 0 1.2rem; }
h1::after { content: ""; display: block; width: 4.5rem; height: .45rem; border-radius: 999px; background: var(--pink); margin-top: .9rem; }
h2 { font-size: 1.45rem; line-height: 1.3; font-weight: 800; margin: 2.4rem 0 .8rem; }
.prose h2 { display: flex; align-items: center; gap: .6rem; }
.prose h2::before { content: ""; flex: none; width: .55rem; height: 1.35rem; border-radius: 999px; background: var(--pink); }
h3 { font-size: 1.15rem; font-weight: 700; margin: 1.6rem 0 .5rem; }
p, ul, ol, table { margin: 0 0 1rem; }
.prose ul, .prose ol { padding-left: 1.4rem; }
.prose li + li { margin-top: .35rem; }
.prose li::marker { color: var(--pink-deep); font-weight: 700; }
.prose img { max-width: 100%; height: auto; border-radius: var(--radius); }
.prose a { text-decoration: underline; text-decoration-thickness: 2px; text-decoration-color: var(--pink); text-underline-offset: .18em; transition: color .15s, text-decoration-color .15s; }
.prose a:hover { color: var(--ink); text-decoration-color: var(--ink); }
.lead { font-size: 1.2rem; line-height: 1.55; color: var(--ink-soft); max-width: 38rem; }
.meta { color: var(--ink-soft); font-size: .92rem; }
.muted { color: var(--ink-soft); }

/* Головна */
.hero { margin-bottom: 2.2rem; }
.hero h1 { font-size: clamp(2.1rem, 1.4rem + 3vw, 3.2rem); line-height: 1.08; }
.cta { display: flex; flex-wrap: wrap; gap: .6rem; margin: 1.3rem 0 0; }
.btn { display: inline-block; padding: .65rem 1.15rem; border-radius: 999px; border: 2px solid var(--ink); font-weight: 700; text-decoration: none; transition: transform .2s, box-shadow .2s, background .2s, color .2s; }
.btn-primary { background: var(--ink); color: var(--pink); }
.btn-primary:hover { color: #fff; transform: translateY(-2px); box-shadow: var(--shadow); }
.btn-ghost { background: transparent; color: var(--ink); }
.btn-ghost:hover { background: var(--pink-soft); transform: translateY(-2px); }

.cards { list-style: none; padding: 0; margin: 0 0 2.5rem; display: grid; gap: 1rem; grid-template-columns: repeat(auto-fit, minmax(13rem, 1fr)); }
.card { position: relative; overflow: hidden; background: var(--paper); border: 1px solid var(--line); border-radius: var(--radius); padding: 1.1rem 1.15rem 1.2rem; box-shadow: 0 2px 0 var(--pink-soft); transition: transform .25s, box-shadow .25s, border-color .25s; }
.card:hover, .card:focus-within { transform: translateY(-4px); box-shadow: var(--shadow); border-color: var(--pink); }
.card .icon { width: 2.7rem; height: 2.7rem; border-radius: 12px; background: var(--pink-soft); color: var(--ink); display: grid; place-items: center; margin-bottom: .8rem; transition: background .25s, transform .25s; }
.card:hover .icon { background: var(--pink); transform: rotate(-6deg); }
.card .icon svg { width: 1.5rem; height: 1.5rem; }
.card h2 { margin: 0 0 .4rem; font-size: 1.15rem; }
.card h2 a { color: var(--ink); text-decoration: none; }
.card h2 a::after { content: ""; position: absolute; inset: 0; }
.card p { margin: 0; font-size: .95rem; color: var(--ink-soft); }

/* Таблиці */
table { border-collapse: separate; border-spacing: 0; width: 100%; font-size: .95rem; background: var(--paper); border: 1px solid var(--line); border-radius: var(--radius); overflow: hidden; }
th, td { text-align: left; vertical-align: top; padding: .6rem .7rem; border-bottom: 1px solid var(--line); }
tr:last-child th, tr:last-child td { border-bottom: 0; }
thead th { background: var(--pink-soft); font-weight: 700; }
tbody th { font-weight: 600; width: 38%; background: #FFFAFB; }

/* Новини */
.post-list { list-style: none; padding: 0; margin: 0; display: grid; gap: .9rem; }
.post-list li { background: var(--paper); border: 1px solid var(--line); border-radius: var(--radius); padding: 1rem 1.1rem; transition: transform .25s, box-shadow .25s, border-color .25s; }
.post-list li:hover { transform: translateY(-3px); box-shadow: var(--shadow); border-color: var(--pink); }
.post-list h2 { margin: 0 0 .3rem; font-size: 1.2rem; }
.post-list h2 a { color: var(--ink); text-decoration: none; }
.post-list h2 a:hover { color: var(--pink-deep); }
.post-list p { margin: 0 0 .25rem; }

/* Підвал */
.site-footer { position: relative; z-index: 1; background: var(--ink); color: #fff; font-size: .95rem; }
.site-footer .wrap { padding-top: 2rem; padding-bottom: 2.4rem; }
.site-footer p { margin: 0 0 .5rem; }
.site-footer a { color: var(--pink); }
.site-footer a:hover { color: #fff; }
.site-footer .muted { color: #D5C9CD; }

/* Іграшки на тлі */
.toys { position: fixed; inset: 0; z-index: 0; overflow: hidden; pointer-events: none; }
.toy { position: absolute; width: var(--size, 9rem); height: var(--size, 9rem); color: var(--ink); opacity: .13; pointer-events: auto; cursor: pointer; transform: translateY(var(--py, 0px)); will-change: transform; transition: opacity .3s; }
.toy:hover { opacity: .3; }
.toy svg { display: block; width: 100%; height: 100%; animation: float var(--dur, 10s) ease-in-out infinite; animation-delay: var(--delay, 0s); }
.toy.wobble svg { animation: wobble .75s ease-in-out; }
@keyframes float { 0%, 100% { transform: translateY(0) rotate(var(--rot, 0deg)); } 50% { transform: translateY(-14px) rotate(calc(var(--rot, 0deg) + 3deg)); } }
@keyframes wobble { 0% { transform: rotate(0) scale(1); } 25% { transform: rotate(-10deg) scale(1.08); } 50% { transform: rotate(9deg) scale(1.1); } 75% { transform: rotate(-4deg) scale(1.04); } 100% { transform: rotate(0) scale(1); } }
.toy-1 { --size: 11rem; left: 2%; top: 13%; --rot: -8deg; --dur: 10s; }
.toy-2 { --size: 8rem; right: 3%; top: 21%; --rot: 10deg; --dur: 12s; --delay: -3s; }
.toy-3 { --size: 9rem; left: 5%; top: 60%; --rot: 6deg; --dur: 11s; --delay: -5s; }
.toy-4 { --size: 12rem; right: 4%; top: 64%; --rot: -5deg; --dur: 13s; --delay: -2s; }
.toy-5 { --size: 7rem; left: 44%; top: 90%; --rot: 12deg; --dur: 9s; --delay: -7s; }
@media (max-width: 72rem) {
  .toy { opacity: .1; }
  .toy-3, .toy-5 { display: none; }
  .toy-1 { --size: 7rem; left: -1rem; top: 56%; }
  .toy-2 { --size: 6rem; right: -.6rem; top: 11%; }
  .toy-4 { --size: 8rem; right: -1.6rem; top: 80%; }
}

/* Поява блоків при прокручуванні (лише з JS) */
html.js .reveal { opacity: 0; transform: translateY(14px); transition: opacity .6s ease, transform .6s ease; }
html.js .reveal.is-visible { opacity: 1; transform: none; }

/* Кнопка «вгору» */
.to-top { position: fixed; right: 1rem; bottom: 1rem; z-index: 30; width: 2.8rem; height: 2.8rem; border-radius: 50%; background: var(--ink); color: var(--pink); display: grid; place-items: center; text-decoration: none; box-shadow: var(--shadow); opacity: 0; transform: translateY(10px); pointer-events: none; transition: opacity .25s, transform .25s, color .2s; }
.to-top.show { opacity: 1; transform: none; pointer-events: auto; }
.to-top:hover { color: #fff; }
.to-top svg { width: 1.2rem; height: 1.2rem; }

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .toy svg, .toy.wobble svg { animation: none; }
  .toy { transform: none; }
  html.js .reveal { opacity: 1; transform: none; transition: none; }
  .card, .post-list li, .btn, .site-nav a, .lang-switch { transition: none; }
}
@media print {
  .site-nav, .lang-switch, .notice, .skip, .toys, .to-top { display: none; }
  body { background: #fff; }
  a { color: inherit; }
}

/* Мобільна шапка: назва окремим рядком, меню одним рядком із прокручуванням, перемикач мови праворуч */
@media (max-width: 48rem) {
  .header-inner { gap: .4rem .6rem; padding-top: .7rem; padding-bottom: .5rem; }
  .brand { flex-basis: 100%; font-size: 1.05rem; }
  .site-nav { flex: 1 1 0; min-width: 0; }
  .site-nav ul { flex-wrap: nowrap; overflow-x: auto; scrollbar-width: none; -webkit-overflow-scrolling: touch; padding: .15rem 0; mask-image: linear-gradient(90deg, #000 92%, transparent); -webkit-mask-image: linear-gradient(90deg, #000 92%, transparent); }
  .site-nav ul::-webkit-scrollbar { display: none; }
  .site-nav a { white-space: nowrap; padding: .3rem .65rem; font-size: .95rem; }
  .lang-switch { order: 3; flex: none; font-size: .85rem; }
  main.wrap { padding-top: 1.8rem; }
  .hero h1 { font-size: clamp(1.9rem, 1.2rem + 4vw, 2.4rem); }
}

/* Виправлення після перевірки доступності та вёрстки */
[id] { scroll-margin-top: calc(var(--header-h, 7rem) + 1rem); }
.to-top { visibility: hidden; transition: opacity .25s, transform .25s, color .2s, visibility 0s .25s; }
.to-top.show { visibility: visible; transition: opacity .25s, transform .25s, color .2s, visibility 0s; }
.site-footer :focus-visible, .notice :focus-visible, .btn-primary:focus-visible, .site-nav .button:focus-visible, .to-top:focus-visible { outline-color: var(--pink); }
td, th { overflow-wrap: anywhere; }
.table-wrap { overflow-x: auto; margin: 0 0 1rem; }
.table-wrap > table { margin: 0; }
.prose table:has(thead th:nth-child(3)) td:nth-child(2) { white-space: nowrap; }
@media (max-width: 48rem) {
  .site-nav ul { padding: .35rem 2.5rem .35rem .25rem; margin-left: -.25rem; scroll-padding-inline-end: 2.5rem; }
  .site-nav a:focus-visible { outline-offset: -2px; }
}
@media print {
  html.js .reveal { opacity: 1 !important; transform: none !important; transition: none; }
  .site-footer { background: none; color: #000; border-top: 1px solid #000; }
  .site-footer a, .site-footer .muted { color: #000; }
  .btn { border-color: #000; background: none; color: #000; }
  .cards .card, .post-list li, table { box-shadow: none; }
}


/* Широка розкладка: текст і прилипаюче оглавлення праворуч */
.page-grid { display: grid; grid-template-columns: minmax(0, var(--text)); gap: 3rem; align-items: start; }
.page-grid > .prose { min-width: 0; }
.toc { display: none; }
@media (min-width: 64rem) {
  .page-grid.has-toc { grid-template-columns: minmax(0, var(--text)) 15rem; }
  .toc { display: block; position: sticky; top: calc(var(--header-h, 6rem) + 1.5rem); font-size: .92rem; }
  .toc h2 { font-size: .8rem; text-transform: uppercase; letter-spacing: .08em; color: var(--ink-soft); margin: 0 0 .6rem; }
  .toc ol { list-style: none; margin: 0; padding: 0; border-left: 2px solid var(--line); }
  .toc li { margin: 0; }
  .toc a { display: block; padding: .3rem .8rem; margin-left: -2px; border-left: 2px solid transparent; color: var(--ink-soft); text-decoration: none; transition: color .15s, border-color .15s, background .15s; }
  .toc a:hover { color: var(--ink); background: var(--pink-soft); }
  .toc a.is-current { color: var(--ink); font-weight: 700; border-left-color: var(--pink-deep); }
}
/* Головна: ширша сітка карток і більший заголовок */
.hero { max-width: 48rem; }
.hero h1 { font-size: clamp(2.1rem, 1.2rem + 3.4vw, 3.8rem); }
.lead { max-width: 42rem; }
.cards { grid-template-columns: repeat(auto-fit, minmax(16rem, 1fr)); gap: 1.25rem; }
.card { padding: 1.4rem 1.5rem 1.5rem; }
.home-prose { max-width: var(--text); }
/* Підвал у три колонки на широких екранах */
.site-footer .wrap { display: grid; gap: .5rem 2rem; }
@media (min-width: 64rem) {
  .site-footer .wrap { grid-template-columns: 2fr 1fr 1fr; align-items: start; }
  .site-footer .muted { grid-column: 1 / -1; }
}
/* Іграшки на широких екранах залишаються на полях */
@media (min-width: 72.01rem) {
  .toy-1 { left: max(1%, calc(50% - 36rem - 12rem)); }
  .toy-3 { left: max(1.5%, calc(50% - 36rem - 10rem)); }
  .toy-2 { right: max(1.5%, calc(50% - 36rem - 9rem)); }
  .toy-4 { right: max(1%, calc(50% - 36rem - 13rem)); }
}

/* Меню мов і перемикач теми */
.header-tools { display: flex; align-items: center; gap: .5rem; }
.lang-nav { display: flex; gap: .15rem; border: 1.5px solid var(--line); border-radius: 999px; padding: .15rem; background: var(--paper); }
.lang-nav a { display: inline-block; padding: .15rem .55rem; border-radius: 999px; font-size: .82rem; font-weight: 700; letter-spacing: .04em; color: var(--ink-soft); text-decoration: none; transition: background .15s, color .15s; }
.lang-nav a:hover { background: var(--pink-soft); color: var(--ink); }
.lang-nav a[aria-current="true"] { background: var(--ink); color: var(--pink); }
.theme-toggle { width: 2.2rem; height: 2.2rem; border-radius: 50%; border: 1.5px solid var(--line); background: var(--paper); color: var(--ink); display: grid; place-items: center; cursor: pointer; padding: 0; transition: background .15s, transform .15s; }
.theme-toggle:hover { background: var(--pink-soft); transform: rotate(-12deg); }
.theme-toggle svg { width: 1.15rem; height: 1.15rem; }
.theme-toggle .icon-sun { display: none; }
.visually-hidden { position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; }

/* Темна тема: за системним налаштуванням або за перемикачем */
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --ink: #F6EEF1; --ink-soft: #CDBFC6; --bg: #151015; --paper: #1F171C; --pink-soft: #3A2630; --pink-deep: #FF9BBA; --line: #3C2B35;
    --notice-bg: #FFC0CB; --notice-ink: #1A1A1A; --shadow: 0 12px 30px rgba(0, 0, 0, .45);
  }
}
:root[data-theme="dark"] {
  --ink: #F6EEF1; --ink-soft: #CDBFC6; --bg: #151015; --paper: #1F171C; --pink-soft: #3A2630; --pink-deep: #FF9BBA; --line: #3C2B35;
  --notice-bg: #FFC0CB; --notice-ink: #1A1A1A; --shadow: 0 12px 30px rgba(0, 0, 0, .45);
}
@media (prefers-color-scheme: dark) { :root:not([data-theme="light"]) .theme-toggle .icon-sun { display: block; } :root:not([data-theme="light"]) .theme-toggle .icon-moon { display: none; } }
:root[data-theme="dark"] .theme-toggle .icon-sun { display: block; }
:root[data-theme="dark"] .theme-toggle .icon-moon { display: none; }
:root[data-theme="light"] .theme-toggle .icon-sun { display: none; }
:root[data-theme="light"] .theme-toggle .icon-moon { display: block; }

/* Темна тема: компоненти, які не живуть лише на змінних */
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) body { background: radial-gradient(60rem 38rem at -10% -10%, #2A1A22 0%, rgba(42, 26, 34, 0) 62%), radial-gradient(48rem 32rem at 108% 18%, #241620 0%, rgba(36, 22, 32, 0) 60%), var(--bg); }
  :root:not([data-theme="light"]) .site-header { background: rgba(21, 16, 21, .86); }
  :root:not([data-theme="light"]) .site-nav a[aria-current="page"], :root:not([data-theme="light"]) .lang-nav a[aria-current="true"] { background: var(--pink); color: #1A1A1A; }
  :root:not([data-theme="light"]) .site-nav .button, :root:not([data-theme="light"]) .btn-primary, :root:not([data-theme="light"]) .to-top, :root:not([data-theme="light"]) .chat-open, :root:not([data-theme="light"]) .chat-send { background: var(--pink); color: #1A1A1A; border-color: var(--pink); }
  :root:not([data-theme="light"]) .site-nav .button:hover, :root:not([data-theme="light"]) .btn-primary:hover { background: #fff; color: #1A1A1A; }
  :root:not([data-theme="light"]) .btn-ghost { border-color: var(--pink); color: var(--ink); }
  :root:not([data-theme="light"]) .toy { color: var(--pink); opacity: .11; }
  :root:not([data-theme="light"]) .site-footer { background: #0D0A0C; }
  :root:not([data-theme="light"]) tbody th { background: #241B20; }
  :root:not([data-theme="light"]) .notice { background: var(--pink); color: #1A1A1A; }
  :root:not([data-theme="light"]) ::selection { background: var(--pink); color: #1A1A1A; }
  :root:not([data-theme="light"]) .skip { background: var(--pink); color: #1A1A1A; }
  :root:not([data-theme="light"]) .msg-user { background: var(--pink); color: #1A1A1A; }
}
:root[data-theme="dark"] body { background: radial-gradient(60rem 38rem at -10% -10%, #2A1A22 0%, rgba(42, 26, 34, 0) 62%), radial-gradient(48rem 32rem at 108% 18%, #241620 0%, rgba(36, 22, 32, 0) 60%), var(--bg); }
:root[data-theme="dark"] .site-header { background: rgba(21, 16, 21, .86); }
:root[data-theme="dark"] .site-nav a[aria-current="page"], :root[data-theme="dark"] .lang-nav a[aria-current="true"] { background: var(--pink); color: #1A1A1A; }
:root[data-theme="dark"] .site-nav .button, :root[data-theme="dark"] .btn-primary, :root[data-theme="dark"] .to-top, :root[data-theme="dark"] .chat-open, :root[data-theme="dark"] .chat-send { background: var(--pink); color: #1A1A1A; border-color: var(--pink); }
:root[data-theme="dark"] .site-nav .button:hover, :root[data-theme="dark"] .btn-primary:hover { background: #fff; color: #1A1A1A; }
:root[data-theme="dark"] .btn-ghost { border-color: var(--pink); color: var(--ink); }
:root[data-theme="dark"] .toy { color: var(--pink); opacity: .11; }
:root[data-theme="dark"] .site-footer { background: #0D0A0C; }
:root[data-theme="dark"] tbody th { background: #241B20; }
:root[data-theme="dark"] .notice { background: var(--pink); color: #1A1A1A; }
:root[data-theme="dark"] ::selection { background: var(--pink); color: #1A1A1A; }
:root[data-theme="dark"] .skip { background: var(--pink); color: #1A1A1A; }
:root[data-theme="dark"] .msg-user { background: var(--pink); color: #1A1A1A; }

/* Чат із Сонею */
.chat { position: fixed; left: 1rem; bottom: 1rem; z-index: 40; font-size: .95rem; }
.chat-open { display: flex; align-items: center; gap: .6rem; padding: .35rem 1rem .35rem .35rem; border: 0; border-radius: 999px; background: var(--ink); color: var(--pink); font: inherit; font-weight: 700; cursor: pointer; box-shadow: var(--shadow); transition: transform .2s, color .2s; }
.chat-open:hover { transform: translateY(-2px); color: #fff; }
.chat-open img { width: 2.6rem; height: 2.6rem; border-radius: 50%; object-fit: cover; border: 2px solid var(--pink); }
.chat-panel { position: absolute; left: 0; bottom: 3.9rem; width: min(24rem, calc(100vw - 2rem)); max-height: min(34rem, calc(100vh - 6rem)); display: flex; flex-direction: column; background: var(--paper); color: var(--ink); border: 1px solid var(--line); border-radius: var(--radius); box-shadow: var(--shadow); overflow: hidden; }
.chat-panel[hidden], .chat[hidden] { display: none; }
.chat-head { display: flex; align-items: center; gap: .6rem; padding: .7rem .8rem; background: var(--pink-soft); border-bottom: 1px solid var(--line); }
.chat-head img { width: 2.4rem; height: 2.4rem; border-radius: 50%; object-fit: cover; }
.chat-head h2 { font-size: .98rem; margin: 0; flex: 1; line-height: 1.25; }
.chat-close { width: 2rem; height: 2rem; border: 0; border-radius: 50%; background: transparent; color: var(--ink); font-size: 1.4rem; line-height: 1; cursor: pointer; }
.chat-close:hover { background: var(--paper); }
.chat-disclaimer { margin: 0; padding: .5rem .8rem; font-size: .76rem; line-height: 1.4; color: var(--ink-soft); border-bottom: 1px solid var(--line); }
.chat-log { flex: 1; overflow-y: auto; padding: .8rem; display: flex; flex-direction: column; gap: .5rem; min-height: 9rem; }
.msg { max-width: 88%; padding: .55rem .75rem; border-radius: 14px; line-height: 1.45; }
.msg p { margin: 0 0 .4rem; }
.msg p:last-child { margin: 0; }
.msg-bot { align-self: flex-start; background: var(--pink-soft); border-bottom-left-radius: 4px; }
.msg-user { align-self: flex-end; background: var(--ink); color: var(--pink); border-bottom-right-radius: 4px; }
.chat-form { display: flex; gap: .5rem; padding: .6rem .8rem; border-top: 1px solid var(--line); }
.chat-form textarea { flex: 1; resize: none; font: inherit; font-size: .95rem; padding: .5rem .6rem; border: 1.5px solid var(--line); border-radius: 10px; background: var(--paper); color: var(--ink); }
.chat-form textarea:focus { border-color: var(--pink-deep); outline: none; }
.chat-send { border: 0; border-radius: 10px; padding: 0 .9rem; background: var(--ink); color: var(--pink); font: inherit; font-weight: 700; cursor: pointer; }
.chat-send:disabled { opacity: .5; cursor: wait; }
.chat-status { margin: 0; padding: 0 .8rem .5rem; font-size: .8rem; color: var(--ink-soft); min-height: 1.2rem; }
.chat-status:empty { padding-bottom: 0; min-height: 0; }
@media (max-width: 48rem) {
  .chat { left: .6rem; bottom: .6rem; }
  .chat-open span { display: none; }
  .chat-open { padding: .25rem; }
  .chat-panel { width: calc(100vw - 1.2rem); bottom: 3.6rem; max-height: calc(100vh - 5rem); }
  .to-top { bottom: .6rem; right: .6rem; }
}
@media print { .chat, .theme-toggle, .lang-nav { display: none; } }

/* Мобільна шапка: три рядки (назва; мови і тема; меню), не липка */
@media (max-width: 48rem) {
  .site-header { position: static; }
  .header-inner { gap: .45rem .5rem; }
  .brand { flex-basis: 100%; }
  .header-tools { flex-basis: 100%; justify-content: space-between; order: 2; }
  .site-nav { flex-basis: 100%; order: 3; }
  .lang-nav a { padding: .15rem .5rem; font-size: .8rem; }
  [id] { scroll-margin-top: 1rem; }
}

/* Доступність темної теми: фокус на рожевих поверхнях, іконки, виділення, textarea, color-scheme */
:root[data-theme="dark"] { color-scheme: dark; }
:root[data-theme="light"] { color-scheme: light; }
.theme-toggle[hidden] { display: none; }
.chat-form textarea { border-color: var(--ink-soft); background: var(--bg); }
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) .site-nav a[aria-current="page"]:focus-visible, :root:not([data-theme="light"]) .site-nav .button:focus-visible, :root:not([data-theme="light"]) .lang-nav a[aria-current="true"]:focus-visible, :root:not([data-theme="light"]) .btn-primary:focus-visible, :root:not([data-theme="light"]) .chat-open:focus-visible { outline-color: #FFFFFF; outline-offset: 3px; }
  :root:not([data-theme="light"]) .card:hover .icon { color: #1A1A1A; }
  :root:not([data-theme="light"]) .toy:hover { opacity: .3; }
  :root:not([data-theme="light"]) .msg-user ::selection, :root:not([data-theme="light"]) .msg-user::selection, :root:not([data-theme="light"]) .notice ::selection, :root:not([data-theme="light"]) .site-nav a[aria-current="page"]::selection, :root:not([data-theme="light"]) .btn-primary::selection { background: #1A1A1A; color: var(--pink); }
}
:root[data-theme="dark"] .site-nav a[aria-current="page"]:focus-visible, :root[data-theme="dark"] .site-nav .button:focus-visible, :root[data-theme="dark"] .lang-nav a[aria-current="true"]:focus-visible, :root[data-theme="dark"] .btn-primary:focus-visible, :root[data-theme="dark"] .chat-open:focus-visible { outline-color: #FFFFFF; outline-offset: 3px; }
:root[data-theme="dark"] .card:hover .icon { color: #1A1A1A; }
:root[data-theme="dark"] .toy:hover { opacity: .3; }
:root[data-theme="dark"] .msg-user ::selection, :root[data-theme="dark"] .msg-user::selection, :root[data-theme="dark"] .notice ::selection, :root[data-theme="dark"] .site-nav a[aria-current="page"]::selection, :root[data-theme="dark"] .btn-primary::selection { background: #1A1A1A; color: var(--pink); }