/* ============================================================
   AquaVolta - eigenstaendiges Theme (Wasser / Wasserstoff).
   Barrierearm: grosse Basis-Schrift, kraeftige Linien, viel Weissraum.
   Ergaenzt Bootstrap 5; ueberschreibt gezielt einzelne Variablen.
   ============================================================ */

:root {
  --av-deep:    #073b4c;
  --av-primary: #0a6e8a;
  --av-teal:    #12a4b8;
  --av-accent:  #1fd4c4;
  --av-ink:     #0d2b34;
  --av-muted:   #4a6670;
  --av-bg:      #f3fafc;
  --av-card:    #ffffff;
  --av-line:    3px;
  --av-gap:     25px;
  --av-radius:  16px;

  --bs-primary: var(--av-primary);
  --bs-link-color: var(--av-primary);
  --bs-link-hover-color: var(--av-deep);
  --bs-body-color: var(--av-ink);
  --bs-body-font-size: 1.125rem;
}

html { scroll-behavior: smooth; scroll-padding-top: 90px; }

body {
  background: var(--av-bg);
  color: var(--av-ink);
  font-size: 1.125rem;
  line-height: 1.65;
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue",
               Arial, "Noto Sans", sans-serif;
  -webkit-font-smoothing: antialiased;
}

.btn-primary {
  --bs-btn-bg: var(--av-primary);
  --bs-btn-border-color: var(--av-primary);
  --bs-btn-hover-bg: var(--av-deep);
  --bs-btn-hover-border-color: var(--av-deep);
  --bs-btn-active-bg: var(--av-deep);
  font-weight: 600;
}
.btn-outline-primary {
  --bs-btn-color: var(--av-primary);
  --bs-btn-border-color: var(--av-primary);
  --bs-btn-hover-bg: var(--av-primary);
  --bs-btn-hover-border-color: var(--av-primary);
  border-width: 2px;
  font-weight: 600;
}

a { text-underline-offset: 2px; }

.skip-link {
  position: absolute; left: 12px; top: 12px; z-index: 1080;
  background: var(--av-deep); color: #fff; padding: .6rem 1rem;
  border-radius: 8px; font-weight: 600;
}

.site-header {
  background: var(--av-card);
  border-bottom: var(--av-line) solid var(--av-teal);
  box-shadow: 0 2px 14px rgba(7, 59, 76, .06);
}
.navbar { padding-block: .7rem; }
.brand {
  font-weight: 800; font-size: 1.5rem; letter-spacing: .2px;
  color: var(--av-deep) !important;
  background: linear-gradient(90deg, var(--av-primary), var(--av-teal));
  -webkit-background-clip: text; background-clip: text;
  -webkit-text-fill-color: transparent;
}
.brand-reg { -webkit-text-fill-color: var(--av-teal); font-size: .7em; vertical-align: super; }
.navbar-nav .nav-link {
  font-weight: 600; color: var(--av-ink); padding-inline: 1rem; border-radius: 8px;
}
.navbar-nav .nav-link:hover { color: var(--av-primary); }
.navbar-nav .nav-link.active {
  color: var(--av-primary); box-shadow: inset 0 -3px 0 var(--av-accent);
}

main { min-height: 60vh; }
h1, h2, h3 { color: var(--av-deep); font-weight: 700; line-height: 1.2; }
.page-title { font-size: clamp(1.9rem, 1.2rem + 2.4vw, 2.9rem); margin-bottom: var(--av-gap); }
.section-heading {
  font-size: 1.7rem; margin-bottom: var(--av-gap);
  padding-bottom: .4rem; border-bottom: var(--av-line) solid var(--av-accent);
  display: inline-block;
}
.lead { font-size: 1.3rem; color: var(--av-muted); }

.home-hero {
  background: linear-gradient(135deg, var(--av-deep) 0%, var(--av-primary) 55%, var(--av-teal) 100%);
  color: #fff; border-radius: var(--av-radius);
  padding: clamp(2rem, 1rem + 5vw, 4.5rem) clamp(1.2rem, .5rem + 4vw, 3.5rem);
  margin-bottom: calc(var(--av-gap) * 1.6);
  box-shadow: 0 18px 50px rgba(7, 59, 76, .22);
}
.eyebrow {
  text-transform: uppercase; letter-spacing: .18em; font-weight: 700;
  font-size: .85rem; color: var(--av-accent); margin-bottom: .8rem;
}
.home-title { color: #fff; font-size: clamp(2rem, 1.2rem + 3.4vw, 3.4rem); margin-bottom: 1rem; }
.home-subtitle { color: rgba(255,255,255,.92); font-size: 1.25rem; max-width: 60ch; }
.home-cta { display: flex; flex-wrap: wrap; gap: 1rem; margin-top: 1.8rem; }
.home-cta .btn-outline-primary {
  --bs-btn-color: #fff; --bs-btn-border-color: rgba(255,255,255,.85);
  --bs-btn-hover-bg: #fff; --bs-btn-hover-color: var(--av-deep);
  --bs-btn-hover-border-color: #fff;
}

.home-intro { max-width: 70ch; margin-bottom: calc(var(--av-gap) * 1.6); }
.home-topics, .home-book { margin-bottom: calc(var(--av-gap) * 1.6); }

.topic-tile {
  display: flex; flex-direction: column; gap: .6rem;
  background: var(--av-card); border: 2px solid #d8edf2;
  border-left: var(--av-line) solid var(--av-teal);
  border-radius: var(--av-radius); padding: calc(var(--av-gap) * .9);
  text-decoration: none; color: var(--av-ink);
  transition: transform .15s ease, box-shadow .15s ease, border-color .15s ease;
  height: 100%;
}
.topic-tile:hover {
  transform: translateY(-4px); box-shadow: 0 14px 32px rgba(10, 110, 138, .18);
  border-left-color: var(--av-accent); color: var(--av-ink);
}
.topic-tile-title { font-size: 1.25rem; margin: 0; }
.topic-tile-text { color: var(--av-muted); margin: 0; flex: 1; }
.topic-tile-count { margin: 0; font-weight: 700; color: var(--av-primary); font-size: .95rem; }

.book-callout {
  background: linear-gradient(120deg, #e8f7fa, #f3fafc);
  border: 2px solid #cfe9ef; border-radius: var(--av-radius);
  padding: clamp(1.4rem, 1rem + 2vw, 2.6rem);
}
.book-callout .section-heading { border-bottom-color: var(--av-teal); }

.page-hero { margin-bottom: calc(var(--av-gap) * 1.3); }
.topic-nav { display: flex; flex-wrap: wrap; gap: .7rem; margin-top: 1.2rem; }
.topic-chip {
  display: inline-block; padding: .5rem 1rem;
  background: #e3f4f8; color: var(--av-primary);
  border: 2px solid #cbe9ef; border-radius: 999px;
  font-weight: 600; text-decoration: none; font-size: 1rem;
}
.topic-chip:hover { background: var(--av-primary); color: #fff; border-color: var(--av-primary); }

.topic-block { margin-bottom: calc(var(--av-gap) * 1.8); }
.topic-heading {
  font-size: 1.7rem; margin-bottom: var(--av-gap);
  padding-bottom: .4rem; border-bottom: var(--av-line) solid var(--av-accent);
}

.video-card {
  display: flex; flex-direction: column;
  background: var(--av-card); border: 2px solid #dceef3;
  border-radius: var(--av-radius); overflow: hidden;
  text-decoration: none; color: var(--av-ink);
  transition: transform .15s ease, box-shadow .15s ease, border-color .15s ease;
  height: 100%;
}
.video-card:hover {
  transform: translateY(-4px); box-shadow: 0 16px 36px rgba(10, 110, 138, .2);
  border-color: var(--av-teal); color: var(--av-ink);
}
.video-card-thumb { background: #d6eef3; }
.video-card-thumb img { object-fit: cover; width: 100%; height: 100%; }
.video-card-body { padding: 1.1rem 1.15rem 1.25rem; flex: 1; }
.video-card-title { font-size: 1.12rem; line-height: 1.3; margin: 0; color: var(--av-deep); }

.video-page { max-width: 75ch; }
.video-page .ratio { border-radius: var(--av-radius); overflow: hidden; box-shadow: 0 10px 30px rgba(7,59,76,.16); }
.video-page h2 { font-size: 1.55rem; margin-top: calc(var(--av-gap) * 1.2); }
.video-page ul { padding-left: 1.3rem; }
.video-page li { margin-bottom: .55rem; }
.video-page .blockquote {
  border-left: var(--av-line) solid var(--av-teal);
  padding: 1rem 1.4rem; background: #eef9fb; border-radius: 0 12px 12px 0;
  font-size: 1.2rem;
}
.video-page .alert { border-radius: 12px; border-width: 2px; }
.video-page section { margin-bottom: var(--av-gap); }

.prose { max-width: 72ch; }
.prose h2 { font-size: 1.6rem; margin-top: calc(var(--av-gap) * 1.2); }
.prose .alert { border-radius: 12px; border-width: 2px; }
.prose .btn { margin-right: .6rem; margin-top: .4rem; }

.site-footer {
  background: var(--av-deep); color: #cfe3e9;
  margin-top: calc(var(--av-gap) * 2);
  padding: calc(var(--av-gap) * 1.6) 0 calc(var(--av-gap));
  border-top: var(--av-line) solid var(--av-teal);
}
.footer-grid {
  display: grid; gap: var(--av-gap);
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  margin-bottom: var(--av-gap);
}
.footer-brand { font-size: 1.4rem; font-weight: 800; color: #fff; margin-bottom: .3rem; }
.footer-note { color: #a9c9d2; margin: 0; }
.footer-head { font-weight: 700; color: #fff; margin-bottom: .6rem; }
.footer-links { list-style: none; padding: 0; margin: 0; }
.footer-links li { margin-bottom: .45rem; }
.footer-links a { color: #cfe3e9; text-decoration: none; }
.footer-links a:hover { color: var(--av-accent); }
.footer-meta {
  border-top: 1px solid rgba(255,255,255,.14); padding-top: 1rem;
  margin: 0; color: #9bbdc6; font-size: .98rem;
}
.footer-meta a { color: var(--av-accent); }

a:focus-visible, .btn:focus-visible, .nav-link:focus-visible {
  outline: 3px solid var(--av-accent); outline-offset: 2px;
}