/* =====================================
   ТЕМА / ЗМІННІ (узгоджено з іншими сторінками)
   ===================================== */
:root{
  --bg: #f5f9ff;
  --panel: #ffffff;
  --ink: #0f172a;
  --ink-2: #334155;
  --muted: #64748b;
  --line: #e5e7eb;
  --brand: #0ea5e9;
  --brand-ink: #083344;
  --ring: rgba(14,165,233,.35);
  --radius-lg: 16px;
  --radius-md: 12px;
  --shadow-1: 0 10px 30px rgba(2,8,23,.06);
  --shadow-2: 0 18px 50px rgba(2,8,23,.08);
}
html[data-theme="dark"]{
  --bg: #0b1220;
  --panel: #0f172a;
  --ink: #e5e7eb;
  --ink-2: #cbd5e1;
  --muted: #94a3b8;
  --line: #1f2937;
  --brand: #38bdf8;
  --brand-ink: #05202a;
  --shadow-1: none;
  --shadow-2: none;
}

/* =====================================
   БАЗА / КОНТЕЙНЕР
   ===================================== */
*,
*::before,
*::after{ box-sizing: border-box; }
html{ scroll-behavior: smooth; }
body{
  margin: 0;
  color: var(--ink);
  background: linear-gradient(180deg, rgba(255,255,255,.9), rgba(255,255,255,.9)), var(--bg);
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Arial, "Noto Sans";
}
main{ max-width: 1200px; margin: 0 auto; padding: 22px 20px 40px; }
img{ max-width: 100%; height: auto; display: block; }
a{ color: inherit; text-decoration: none; }
:focus-visible{ outline: 2px solid var(--brand); outline-offset: 2px; }

/* =====================================
   ЗАГОЛОВКИ / БЕЙДЖ ГРУПИ
   ===================================== */
h2{
  text-align: center;
  font-size: clamp(1.3rem, 1.1rem + 1vw, 1.8rem);
  font-weight: 900;
  margin: 0 0 14px;
}
.group-title{
  background: #eef6ff;
  border: 1px solid #c7ddff;
  border-left: 6px solid #2a6df0;
  padding: 10px 12px;
  font-weight: 800;
  border-radius: 12px;
  margin: 18px 0 12px;
}

/* =====================================
   СІТКА КАРТОК (під існуючі класи)
   ===================================== */
.grid{ display: grid; gap: 16px; }
.grid-cols-1{ grid-template-columns: 1fr; }
.grid-cols-2{ grid-template-columns: repeat(2, 1fr); }
.grid-cols-3{ grid-template-columns: repeat(3, 1fr); }

/* адаптив: зменшуємо кількість колонок поступово */
@media (max-width: 1100px){ .grid-cols-3{ grid-template-columns: repeat(2, 1fr); } }
@media (max-width: 640px){
  .grid-cols-2, .grid-cols-3{ grid-template-columns: 1fr; }
}

/* =====================================
   КАРТКИ СТАТЕЙ (article.card)
   ===================================== */
.card{
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-1);
  padding: 14px;
  transition: transform .25s ease, box-shadow .25s ease, border-color .25s ease;
}
.card:hover{
  transform: translateY(-2px);
  box-shadow: var(--shadow-2);
  border-color: color-mix(in srgb, var(--brand) 30%, var(--line));
}
.card h3{
  margin: 0 0 8px;
  font-size: 1.06rem;
  line-height: 1.35;
  color: var(--ink);
}
.muted{ color: var(--muted); margin: 2px 0; }
.stack{ display: flex; gap: 12px; flex-wrap: wrap; align-items: flex-start; margin-top: 8px; }

/* =====================================
   PDF-ПРЕВ’Ю (через <embed.preview-pdf>)
   ===================================== */
.preview-pdf{
  display: block;
  width: 100%;
  height: 300px;               /* вікно прев’ю */
  background: #fff;
  border: 1px solid var(--line);
  border-radius: 12px;
  box-shadow: 0 6px 16px rgba(2,8,23,.08);
}
@media (max-width: 760px){ .preview-pdf{ height: 240px; } }

/* =====================================
   КНОПКИ
   ===================================== */
.btn{
  display: inline-flex; align-items: center; justify-content: center;
  height: 40px; padding: 0 16px;
  border-radius: 12px; font-weight: 800;
  border: 1px solid var(--brand);
  background: var(--brand);
  color: #fff;
  transition: transform .2s ease, box-shadow .2s ease, background .2s ease;
}
.btn:hover{
  transform: translateY(-1px);
  box-shadow: 0 8px 20px var(--ring);
  background: color-mix(in srgb, var(--brand), #000 10%);
}

/* =====================================
   REVEAL-Анімація (узгоджено з іншими сторінками)
   ===================================== */
.reveal{ opacity: 0; transform: translateY(14px); transition: opacity .5s ease, transform .5s ease; }
.reveal.is-visible{ opacity: 1; transform: translateY(0); }
@media (prefers-reduced-motion: reduce){
  .reveal{ opacity: 1 !important; transform: none !important; transition: none !important; }
}

/* =====================================
   ФУТЕР (спільний стиль)
   ===================================== */
footer{
  margin-top: 28px; padding: 20px; text-align: center; color: var(--muted);
  background: transparent;
}
footer .banner{ margin: 12px auto 0; max-width: 320px; border-radius: 8px; }