/* Czech Studies — landing page
   Plain CSS, no framework. Palette nods to the Czech flag: white, blue, red. */

:root {
  --blue:   #11457e;
  --blue-2: #1a5fb4;
  --red:    #d7141a;
  --ink:    #1c2430;
  --muted:  #5b6472;
  --bg:     #f7f8fa;
  --card:   #ffffff;
  --line:   #e6e9ee;
  --radius: 14px;
  --shadow: 0 1px 2px rgba(16,24,40,.06), 0 8px 24px rgba(16,24,40,.06);
}

* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  color: var(--ink);
  background: var(--bg);
  line-height: 1.55;
}

.wrap { width: min(1040px, 92vw); margin-inline: auto; }

/* ---- Header ---- */
.site-header {
  background: linear-gradient(135deg, var(--blue) 0%, var(--blue-2) 100%);
  color: #fff;
  padding: 1.0rem 0 1.8rem;
  border-bottom: 2px solid var(--red);
}
.site-title {
  margin: 0;
  font-size: clamp(2rem, 4vw, 3rem);
  font-weight: 600;
  letter-spacing: -0.02em;
}
.site-tagline { margin: .6rem 0 .2rem; font-size: 1.05rem; opacity: .95; }
.site-subtagline { margin: 0; font-size: .95rem; opacity: .8; }

/* ---- Sections (collapsible <details>) ---- */
.group { margin-top: 2.4rem; }
.group:first-of-type { margin-top: 2rem; }

.group-summary {
  list-style: none;
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: .6rem;
  padding: .15rem 0;
  user-select: none;
}
.group-summary::-webkit-details-marker { display: none; }

/* Triangle marker that rotates when the section is open */
.group-summary::before {
  content: "";
  flex: 0 0 auto;
  width: 0; height: 0;
  border-left: 8px solid var(--red);
  border-top: 5px solid transparent;
  border-bottom: 5px solid transparent;
  transition: transform .15s ease;
}
.group[open] > .group-summary::before { transform: rotate(90deg); }

.group-summary:focus-visible { outline: 2px solid var(--blue-2); outline-offset: 3px; border-radius: 4px; }

.group-title { font-size: 1.35rem; font-weight: 700; }
.group-desc { margin: .5rem 0 1.2rem; color: var(--muted); font-size: .95rem; }

/* ---- Sub-sections ---- */
.subgroup-title {
  margin: 1.4rem 0 .8rem;
  font-size: 1.02rem;
  font-weight: 700;
  color: var(--blue);
}

/* ---- Card grid ---- */
.cards {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
  gap: 1rem;
}
.card {
  display: flex;
  flex-direction: column;
  gap: .35rem;
  padding: 1.1rem 1.15rem;
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  text-decoration: none;
  color: inherit;
  transition: transform .12s ease, box-shadow .12s ease, border-color .12s ease;
}
.card:hover {
  transform: translateY(-3px);
  box-shadow: 0 2px 4px rgba(16,24,40,.08), 0 14px 34px rgba(16,24,40,.12);
  border-color: #d3dae4;
}
.card-tag {
  align-self: flex-start;
  font-size: .7rem;
  font-weight: 700;
  letter-spacing: .04em;
  text-transform: uppercase;
  color: var(--blue);
  background: #eaf1fb;
  padding: .15rem .5rem;
  border-radius: 999px;
}
.card-title { font-weight: 700; font-size: 1.02rem; }
.card-desc { color: var(--muted); font-size: .9rem; }

/* ---- Footer ---- */
.site-footer {
  margin-top: 3.5rem;
  padding: 1.6rem 0;
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: .88rem;
}

/* ---- Small screens (phones) ---- */
@media (max-width: 480px) {
  .site-header { padding: 2.4rem 0 2rem; }
  .cards { grid-template-columns: 1fr; }
}