/* Landing page. RUB corporate colours:
   https://services.ruhr-uni-bochum.de/de/rub-farben
   Blue carries text and buttons; green (low contrast on white) is used
   only for accents such as rules, tags and hover states. */
:root {
  --rub-blue: #17365c;
  --rub-green: #8dae10;
  --rub-grey: #e7e7e7;
  --ink: #17365c;
  --text: #3c3c3c;
  --muted: #6b7280;
  --line: #e7e7e7;
  --accent: #17365c;
  --accent-hover: #0f2542;
  --accent-soft: #eef3e0;
  --card: #ffffff;
  --page: #f4f4f4;
  --marimo: #1c7c54;
  --pluto: #7b4bb3;
  --site-font: "Helvetica Neue", HelveticaNeue, Helvetica, Arial, sans-serif;
}

body {
  background: var(--page);
  color: var(--text);
  font-family: var(--site-font);
}
a { color: var(--rub-blue); text-decoration-color: var(--rub-green); }
a:hover { color: var(--accent-hover); }

main.content { max-width: 1180px; margin: 0 auto; }

/* Hero */
.hero {
  align-items: center;
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 20px;
  border-top: 6px solid var(--rub-green);
  display: grid;
  gap: 1rem 2.2rem;
  grid-template-columns: 190px 1fr;
  margin: 1.5rem 0 2.5rem;
  padding: 2.2rem 2.5rem 1.8rem;
}
.hero p.hero-logo, .hero .hero-logo { margin: 0; }
.hero img.hero-logo, .hero .hero-logo img { display: block; height: auto; width: 190px; }
.hero-copy { min-width: 0; }
.hero-group {
  align-items: center;
  border-top: 1px solid var(--line);
  display: flex;
  gap: 0.8rem;
  grid-column: 1 / -1;
  padding-top: 1rem;
}
.hero-group p { margin: 0; }
.hero-group img { height: 46px; width: 46px; }
.group-name { color: var(--muted); font-size: 0.85rem; line-height: 1.3; }
.hero-kicker {
  color: var(--rub-blue);
  font-size: 0.85rem;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}
.hero h1.hero-title {
  border: 0;
  font-size: clamp(2rem, 5vw, 3.2rem);
  font-weight: 700;
  color: var(--rub-blue);
  letter-spacing: -0.02em;
  margin: 0.4rem 0 0.8rem;
}
.hero p { color: var(--muted); font-size: 1.1rem; max-width: 46rem; }
.hero-links { display: flex; flex-wrap: wrap; gap: 0.6rem; margin-top: 1.2rem; }

/* Section headings */
h2.section-title {
  border: 0;
  color: var(--rub-blue);
  font-size: 1.6rem;
  font-weight: 700;
  margin: 2.5rem 0 0.4rem;
}
.section-note { color: var(--muted); margin-bottom: 1.2rem; max-width: 52rem; }
.section-note p { margin: 0; }
kbd {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 4px;
  color: var(--ink);
  font-size: 0.8em;
  padding: 0 0.35em;
}

/* Cards */
.card-grid {
  display: grid;
  gap: 1.1rem;
  grid-template-columns: repeat(auto-fill, minmax(min(100%, 330px), 1fr));
}
.course-card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 16px;
  display: flex;
  flex-direction: column;
  overflow: hidden;
  transition: border-color 0.15s, box-shadow 0.15s, transform 0.15s;
}
.course-card:hover {
  border-color: var(--rub-green);
  box-shadow: 0 6px 22px rgba(23, 54, 92, 0.12);
  transform: translateY(-2px);
}
.course-card:target { border-color: var(--rub-green); box-shadow: 0 0 0 3px var(--accent-soft); }
.course-card { border-top: 4px solid var(--rub-blue); }
.exercise-card { border-top-color: var(--rub-green); }
.stats-card { max-width: 680px; }
.card-text { color: var(--text); font-size: 0.95rem; margin: 0.7rem 0 0; }

.card-head {
  color: inherit;
  display: block;
  padding: 1.2rem 1.3rem 0.6rem;
  text-decoration: none;
}
.card-head:hover { color: inherit; }
.card-tag {
  color: var(--muted);
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.05em;
  text-transform: uppercase;
}
.card-title {
  border: 0;
  font-size: 1.3rem;
  font-weight: 700;
  color: var(--rub-blue);
  line-height: 1.25;
  margin: 0.3rem 0 0.5rem;
}
.card-meta {
  color: var(--muted);
  display: flex;
  flex-wrap: wrap;
  font-size: 0.9rem;
  gap: 0.3rem 1rem;
  margin: 0;
}

.card-actions {
  align-items: center;
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  padding: 0.4rem 1.3rem 1rem;
}

.btn-main, .chip {
  border-radius: 999px;
  font-size: 0.9rem;
  font-weight: 600;
  padding: 0.35rem 0.95rem;
  text-decoration: none;
}
.btn-main { background: var(--accent); border: 1px solid var(--accent); color: #fff; }
.btn-main:hover { background: var(--accent-hover); border-color: var(--accent-hover); color: #fff; }
.chip { background: var(--card); border: 1px solid var(--line); color: var(--ink); }
.chip:hover { border-color: var(--rub-green); color: var(--rub-blue); }

/* Attached notebooks */
.materials {
  border-top: 1px solid var(--line);
  list-style: none;
  margin: auto 0 0;
  padding: 0.6rem 1.3rem 0.8rem;
}
.materials li {
  align-items: center;
  display: flex;
  font-size: 0.88rem;
  gap: 0.55rem;
  padding: 0.22rem 0;
}
.materials .label { flex: 1 1 auto; min-width: 0; }
.materials .links { display: flex; gap: 0.6rem; white-space: nowrap; }
.materials .links a { color: var(--accent); text-decoration: none; }
.materials .links a:hover { text-decoration: underline; }
.kind {
  border-radius: 6px;
  flex: 0 0 auto;
  font-size: 0.68rem;
  font-weight: 700;
  letter-spacing: 0.04em;
  padding: 0.1rem 0.45rem;
  text-transform: uppercase;
}
.kind-marimo { background: #e6f4ec; color: var(--marimo); }
.kind-pluto { background: #f1eafa; color: var(--pluto); }

@media (max-width: 700px) {
  .hero { grid-template-columns: 1fr; justify-items: start; padding: 1.6rem 1.3rem 1.4rem; }
  .hero img.hero-logo, .hero .hero-logo img { width: 130px; }
  .materials li { flex-wrap: wrap; }
}