/* ============================================================
   Unterseite „Gewässer" — bildstarker Tauchgang
   ============================================================ */

/* ============ Kopf ============ */

.ghead {
  position: relative;
  min-height: 26rem;
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
  padding: 8rem 1.5rem 3.5rem;
  background: var(--navy-900);
}

.ghead__bg {
  position: absolute;
  inset: -4% 0;
}

.ghead__bg img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center 48%;
}

.ghead__tint {
  position: absolute;
  inset: 0;
  background:
    linear-gradient(180deg, rgba(6, 13, 26, 0.82) 0%, rgba(8, 18, 35, 0.5) 42%, var(--navy-900) 100%),
    linear-gradient(110deg, rgba(6, 13, 26, 0.46) 0%, transparent 62%, rgba(242, 160, 60, 0.08) 100%);
}

.ghead .waters__head {
  position: relative;
  z-index: 2;
  margin-bottom: 0;
  text-shadow: 0 2px 18px rgba(0, 0, 0, 0.5);
}

.ghead,
.kap { scroll-margin-top: 5.5rem; }

/* ============ Tauchgang: Kapitel ============ */

.dive { position: relative; }

.kap {
  position: relative;
  overflow: hidden;
  padding: 4.5rem 1.5rem 5rem;
  /* Tiefen-Tönung: pro Kapitel dunkler und blauer */
  background:
    radial-gradient(900px 480px at 15% 10%, rgba(27, 79, 170, calc(0.18 - var(--depth) * 0.03)), transparent 65%),
    linear-gradient(180deg,
      hsl(217, 62%, calc(9% - var(--depth) * 1.4%)),
      hsl(219, 66%, calc(6% - var(--depth) * 1.1%)));
  border-top: 1px solid rgba(232, 237, 245, 0.05);
}

/* Kaustik-Lichtflecken */
.kap__caustics { position: absolute; inset: 0; pointer-events: none; }
.kap__caustics span {
  position: absolute;
  width: 46vw;
  height: 46vw;
  max-width: 640px;
  max-height: 640px;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(90, 150, 230, 0.09) 0%, transparent 65%);
  filter: blur(10px);
  animation: causticDrift 22s ease-in-out infinite alternate;
}
.kap__caustics span:nth-child(1) { top: -12%; left: -8%; }
.kap__caustics span:nth-child(2) { top: 30%; right: -12%; animation-duration: 28s; animation-delay: -9s; }
.kap__caustics span:nth-child(3) { bottom: -18%; left: 30%; animation-duration: 25s; animation-delay: -16s;
  background: radial-gradient(circle, rgba(242, 201, 76, 0.05) 0%, transparent 65%); }

@keyframes causticDrift {
  from { transform: translate(0, 0) scale(1); }
  to   { transform: translate(6vw, 4vh) scale(1.15); }
}

.kap__inner {
  position: relative;
  z-index: 1;
  max-width: 1240px;
  margin: 0 auto;
  width: 100%;
}

.kap__head {
  margin-bottom: 0.9rem;
}

.kap__no {
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--gold);
  margin-bottom: 0.6rem;
}

.kap__title {
  font-family: var(--font-display);
  font-weight: 500;
  font-size: clamp(2.2rem, 4.5vw, 3.4rem);
  line-height: 1.05;
}
.kap__title em {
  font-style: italic;
  font-weight: 600;
  background: linear-gradient(100deg, #dbe7ee 0%, var(--gold) 70%, var(--gold-strong) 100%);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  padding-right: 0.1em;
}

.kap__story {
  color: var(--text-dim);
  font-size: 1.02rem;
  max-width: 44rem;
  margin-bottom: 1.8rem;
}

.kap__story p + p { margin-top: 0.7rem; }

/* ============ Foto-Mosaik ============ */

.mosaic {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  grid-auto-rows: 240px;
  gap: 1rem;
}

/* großes Hauptbild links über 2 Reihen */
.mosaic__item--hero { grid-column: span 2; grid-row: span 2; }
/* Hochformat rechts über 2 Reihen (nur Erlensee-Mosaik mit 4 Bildern) */
.mosaic__item--tall { grid-row: span 2; }

/* 3er-Mosaik: Hauptbild rechts statt links */
.mosaic--flip .mosaic__item--hero { grid-column: 2 / 4; grid-row: 1 / 3; }
.mosaic--flip .mosaic__item:nth-child(2) { grid-column: 1; grid-row: 1; }
.mosaic--flip .mosaic__item:nth-child(3) { grid-column: 1; grid-row: 2; }

.mosaic__item {
  position: relative;
  margin: 0;
  border-radius: 18px;
  overflow: hidden;
  border: 1px solid rgba(232, 237, 245, 0.1);
  box-shadow: 0 14px 38px rgba(0, 0, 0, 0.4);
}

.mosaic__item img {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform 0.8s var(--ease-out), filter 0.5s ease;
}

.mosaic__item::after {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(180deg, transparent 55%, rgba(6, 13, 26, 0.45) 100%);
  opacity: 0.7;
  transition: opacity 0.4s ease;
  pointer-events: none;
}

@media (hover: hover) and (pointer: fine) {
  .mosaic__item:hover img { transform: scale(1.06); }
  .mosaic__item:hover::after { opacity: 0.25; }
}

/* ============ Echolot ============ */

.sonar {
  position: fixed;
  right: 1.6rem;
  top: 50%;
  transform: translateY(-50%) translateX(0);
  z-index: 50;
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
  padding: 1.1rem 0.9rem;
  border-radius: 999px;
  border: 1px solid rgba(232, 237, 245, 0.12);
  background: rgba(8, 17, 31, 0.6);
  -webkit-backdrop-filter: blur(12px);
  backdrop-filter: blur(12px);
  opacity: 1;
  visibility: visible;
  transition: opacity 0.4s var(--ease-out), transform 0.4s var(--ease-out), visibility 0.4s;
}
.js .sonar {
  opacity: 0;
  visibility: hidden;
  transform: translateY(-50%) translateX(16px);
}
.js .sonar.is-visible {
  opacity: 1;
  visibility: visible;
  transform: translateY(-50%) translateX(0);
}

.sonar__track {
  position: absolute;
  left: 50%;
  top: 1.6rem;
  bottom: 1.6rem;
  width: 2px;
  transform: translateX(-50%);
  background: rgba(232, 237, 245, 0.12);
  border-radius: 2px;
  overflow: hidden;
}
.sonar__fill {
  display: block;
  width: 100%;
  height: 0%;
  background: linear-gradient(180deg, var(--gold), var(--gold-strong));
}

.sonar__stop {
  position: relative;
  z-index: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  min-height: 44px;
}
.sonar__dot {
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: var(--navy-900);
  border: 2px solid rgba(232, 237, 245, 0.35);
  transition: border-color 0.25s ease, background-color 0.25s ease, box-shadow 0.25s ease;
}
.sonar__stop.is-active .sonar__dot,
.sonar__stop[aria-current="location"] .sonar__dot {
  background: var(--gold);
  border-color: var(--gold);
  box-shadow: 0 0 12px rgba(242, 201, 76, 0.7);
}

.sonar__name {
  position: absolute;
  right: calc(100% + 0.9rem);
  top: 50%;
  transform: translateY(-50%) translateX(6px);
  white-space: nowrap;
  font-size: 0.78rem;
  font-weight: 600;
  color: var(--text);
  background: rgba(8, 17, 31, 0.85);
  border: 1px solid rgba(242, 201, 76, 0.3);
  border-radius: 999px;
  padding: 0.3rem 0.75rem;
  opacity: 0;
  transition: opacity 0.25s ease, transform 0.25s var(--ease-out);
  pointer-events: none;
}
.sonar__stop:hover .sonar__name,
.sonar__stop:focus-visible .sonar__name,
.sonar__stop.is-active .sonar__name,
.sonar__stop[aria-current="location"] .sonar__name {
  opacity: 1;
  transform: translateY(-50%) translateX(0);
}

/* Ohne JavaScript bleibt das Echolot als echte, horizontale Sprungnavigation
   verfügbar. Erst die .js-Klasse macht daraus das scroll-reaktive Instrument. */
html:not(.js) .sonar {
  position: sticky;
  top: 4.5rem;
  right: auto;
  transform: none;
  z-index: 60;
  flex-direction: row;
  justify-content: center;
  gap: 0.45rem;
  width: 100%;
  padding: 0.65rem 1rem;
  border-inline: 0;
  border-radius: 0;
  background: color-mix(in oklch, var(--navy-950) 92%, transparent);
  opacity: 1;
  visibility: visible;
  overflow-x: auto;
}
html:not(.js) .sonar__track { display: none; }
html:not(.js) .sonar__stop {
  flex: 0 0 auto;
  width: auto;
  gap: 0.45rem;
  padding: 0.3rem 0.7rem;
  border: 1px solid rgba(232, 237, 245, 0.16);
  border-radius: 999px;
}
html:not(.js) .sonar__dot { width: 9px; height: 9px; }
html:not(.js) .sonar__name {
  position: static;
  transform: none;
  padding: 0;
  border: 0;
  background: transparent;
  opacity: 1;
  pointer-events: auto;
}

/* ============ Reduced Motion ============ */

@media (prefers-reduced-motion: reduce) {
  .kap__caustics span { animation: none; }
}

/* ============ Responsive ============ */

@media (max-width: 1024px) {
  .sonar,
  .js .sonar,
  .js .sonar.is-visible {
    position: sticky;
    top: 4.4rem;
    right: auto;
    transform: none;
    z-index: 60;
    display: flex;
    flex-direction: row;
    justify-content: center;
    gap: 0.45rem;
    width: 100%;
    padding: 0.65rem 1rem;
    border-inline: 0;
    border-radius: 0;
    background: rgba(8, 17, 31, 0.92);
    opacity: 1;
    visibility: visible;
    overflow-x: auto;
  }
  .sonar__track { display: none; }
  .sonar__stop {
    flex: 0 0 auto;
    width: auto;
    gap: 0.45rem;
    padding: 0.3rem 0.7rem;
    border: 1px solid rgba(232, 237, 245, 0.16);
    border-radius: 999px;
  }
  .sonar__dot { width: 9px; height: 9px; }
  .sonar__name,
  .sonar__stop:hover .sonar__name,
  .sonar__stop:focus-visible .sonar__name,
  .sonar__stop.is-active .sonar__name,
  .sonar__stop[aria-current="location"] .sonar__name {
    position: static;
    transform: none;
    padding: 0;
    border: 0;
    background: transparent;
    opacity: 1;
    pointer-events: auto;
  }
  .mosaic { grid-auto-rows: 200px; }
}

@media (max-width: 820px) {
  html:not(.js) .sonar { top: 0; }
}

@media (max-width: 700px) {
  .ghead { min-height: 24rem; padding-top: 6.5rem; }
  .ghead__bg img { object-position: 58% center; }
  .sonar,
  .js .sonar,
  .js .sonar.is-visible { justify-content: flex-start; }
  html:not(.js) .sonar { top: 0; }
  .mosaic,
  .mosaic--flip { grid-template-columns: 1fr 1fr; grid-auto-rows: 170px; gap: 0.7rem; }
  .mosaic__item--hero,
  .mosaic--flip .mosaic__item--hero { grid-column: 1 / 3; grid-row: span 2; }
  .mosaic__item--tall { grid-row: span 1; }
  .mosaic--flip .mosaic__item:nth-child(2),
  .mosaic--flip .mosaic__item:nth-child(3) { grid-column: auto; grid-row: auto; }
}