/* Lernmodul "Wenn Sand nass wird" – Gestaltung
   Farben als Tokens; das Modul läuft eingebettet in OPAL (heller Rahmen),
   deshalb bewusst nur ein helles Farbschema. */
:root {
  color-scheme: light;
  --flaeche: #fcfcfb;
  --flaeche-2: #f4f3f0;
  --flaeche-3: #ebe9e4;
  --linie: #dcdad4;
  --linie-stark: #c3c1b9;
  --tinte: #141413;
  --tinte-2: #52514e;
  --tinte-3: #7a7871;
  --akzent: #0064a8;          /* TUBAF-Blau */
  --akzent-dunkel: #004b7f;
  --akzent-hell: #e3eef7;
  --wasser: #2a78d6;
  --wasser-hell: #cde2fb;
  --luft: #ffffff;
  --korn: #3d3c39;
  --sand: #e8cf94;
  --sand-dunkel: #c9a75a;
  --suspension: #9fc3e6;
  --orange: #eb6834;
  --aqua: #1baf7a;
  --gut: #1a7f37;
  --gut-hell: #e4f3e8;
  --schlecht: #c62828;
  --schlecht-hell: #fbe9e9;
  --warn: #b26a00;
  --radius: 10px;
  --radius-klein: 6px;
  --schatten: 0 1px 2px rgba(20, 20, 19, .06), 0 4px 16px rgba(20, 20, 19, .06);
  --schrift: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --mono: ui-monospace, "SFMono-Regular", Menlo, Consolas, "Liberation Mono", monospace;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  background: var(--flaeche);
  color: var(--tinte);
  font: 16px/1.6 var(--schrift);
  -webkit-font-smoothing: antialiased;
}
/* Auf einer Webseite eingebettet: Die Seite passt die iframe-Höhe an, also keine eigene Scrollleiste. */
html.eingebettet, html.eingebettet body { overflow: hidden; }
img, video, svg { max-width: 100%; }
img, video { height: auto; display: block; }
a { color: var(--akzent); }
a:hover { color: var(--akzent-dunkel); }
:focus-visible { outline: 3px solid var(--akzent); outline-offset: 2px; border-radius: 4px; }
h1, h2, h3, h4 { line-height: 1.2; margin: 0 0 .5em; text-wrap: balance; }
h1 { font-size: clamp(2rem, 5vw, 3.1rem); letter-spacing: -.02em; }
h2 { font-size: clamp(1.55rem, 3.4vw, 2.05rem); letter-spacing: -.01em; }
h3 { font-size: 1.2rem; margin-top: 1.6em; }
h4 { font-size: 1rem; margin-top: 1.2em; }
p { margin: 0 0 1em; }
.leise { color: var(--tinte-2); }
.klein { font-size: .875rem; }
.zahl { font-variant-numeric: tabular-nums; }

/* ---------------------------------------------------------------- Kopfleiste */
.kopf {
  position: sticky; top: 0; z-index: 20;
  background: rgba(252, 252, 251, .94);
  backdrop-filter: blur(6px);
  border-bottom: 1px solid var(--linie);
}
.kopf-innen {
  max-width: 1040px; margin: 0 auto; padding: 8px 16px 6px;
  display: flex; align-items: center; gap: 6px 16px; flex-wrap: wrap;
}
.marke {
  font-weight: 700; text-decoration: none; color: var(--tinte);
  white-space: nowrap; display: flex; align-items: center; gap: 8px;
}
.marke svg { flex: none; }
.kapitelnav {
  display: flex; gap: 4px; overflow-x: auto; order: 3; flex: 1 1 100%; scrollbar-width: none;
  margin: 0 -6px;
}
.fortschritt { margin-left: auto; }
.kapitelnav::-webkit-scrollbar { display: none; }
.kapitelnav a {
  flex: none; display: flex; align-items: center; gap: 6px;
  padding: 6px 10px; border-radius: 999px; font-size: .875rem;
  text-decoration: none; color: var(--tinte-2); white-space: nowrap;
}
.kapitelnav a:hover { background: var(--flaeche-2); color: var(--tinte); }
.kapitelnav a[aria-current="page"] { background: var(--akzent); color: #fff; }
.kapitelnav .nr {
  width: 20px; height: 20px; border-radius: 50%; display: inline-grid; place-items: center;
  font-size: .75rem; font-weight: 700; background: var(--flaeche-3); color: var(--tinte-2);
}
.kapitelnav a[aria-current="page"] .nr { background: rgba(255,255,255,.25); color: #fff; }
.kapitelnav a.besucht:not([aria-current]) .nr { background: var(--gut); color: #fff; }
.fortschritt { display: flex; align-items: center; gap: 8px; font-size: .8rem; color: var(--tinte-2); white-space: nowrap; }
.fortschritt .balken { width: 72px; height: 6px; background: var(--flaeche-3); border-radius: 3px; overflow: hidden; }
.fortschritt .balken i { display: block; height: 100%; width: 0; background: var(--gut); transition: width .4s; }
@media (max-width: 720px) {
  .marke .marke-text { font-size: .95rem; }
}

/* ---------------------------------------------------------------- Kapitel */
main { max-width: 1040px; margin: 0 auto; padding: 24px 16px 64px; }
.js .kapitel { display: none; }
.js .kapitel.aktiv { display: block; animation: einblenden .35s ease; }
@keyframes einblenden { from { opacity: 0; transform: translateY(6px); } to { opacity: 1; transform: none; } }
.kapitel-kopf { margin: 8px 0 24px; max-width: 760px; }
.kicker {
  display: inline-block; font-size: .78rem; font-weight: 700; letter-spacing: .06em;
  text-transform: uppercase; color: var(--akzent); margin-bottom: 8px;
}
.lead { font-size: 1.15rem; color: var(--tinte-2); }
.hinweis { font-size: .85rem; color: var(--tinte-3); margin: 12px 0 6px; }
.dauer { font-size: .85rem; color: var(--tinte-3); }
.text { max-width: 760px; }

.kapitel-fuss {
  display: flex; justify-content: space-between; gap: 12px; flex-wrap: wrap;
  margin-top: 48px; padding-top: 20px; border-top: 1px solid var(--linie);
}

/* ---------------------------------------------------------------- Bausteine */
.knopf {
  display: inline-flex; align-items: center; gap: 8px; cursor: pointer;
  font: inherit; font-weight: 600; font-size: .95rem;
  padding: 10px 18px; border-radius: 999px; border: 1px solid var(--linie-stark);
  background: #fff; color: var(--tinte); text-decoration: none;
  transition: background .15s, border-color .15s, transform .1s;
}
.knopf:hover { background: var(--flaeche-2); color: var(--tinte); }
.knopf:active { transform: translateY(1px); }
.knopf.primaer { background: var(--akzent); border-color: var(--akzent); color: #fff; }
.knopf.primaer:hover { background: var(--akzent-dunkel); }
.knopf.klein { padding: 6px 12px; font-size: .85rem; }
.knopf[disabled] { opacity: .45; cursor: not-allowed; }

.karte {
  background: #fff; border: 1px solid var(--linie); border-radius: var(--radius);
  padding: 20px; box-shadow: var(--schatten);
}
.raster { display: grid; gap: 16px; }
.raster-2 { grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); }
.raster-3 { grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); }
.zwei-spalten { display: grid; grid-template-columns: 1.1fr .9fr; gap: 28px; align-items: start; }
.zwei-spalten.eng { gap: 20px; }
.zwei-spalten.gleich { grid-template-columns: 1fr 1fr; gap: 20px; }
.zwei-spalten.breit-schmal { grid-template-columns: 1.35fr .65fr; gap: 20px; }
.saeule-raster { display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 2.4fr); gap: 20px; align-items: start; max-width: 780px; }
.legende i.feld { width: 12px; height: 12px; border: 0; border-radius: 2px; }
@media (max-width: 820px) { .zwei-spalten, .zwei-spalten.breit-schmal, .zwei-spalten.gleich { grid-template-columns: 1fr; } }
@media (max-width: 520px) { .saeule-raster { gap: 8px; } }

figure { margin: 0; }
figcaption { font-size: .85rem; color: var(--tinte-2); margin-top: 8px; line-height: 1.45; }
.medien { border-radius: var(--radius); overflow: hidden; background: var(--flaeche-2); border: 1px solid var(--linie); }
.medien video, .medien img { width: 100%; }

.infobox {
  border-radius: var(--radius); padding: 16px 20px; margin: 20px 0;
  background: var(--akzent-hell); border-left: 4px solid var(--akzent);
}
.infobox h4 { margin: 0 0 6px; color: var(--akzent-dunkel); }
.infobox p:last-child { margin-bottom: 0; }
.infobox.idee { background: #fff6e0; border-left-color: #e0a100; }
.infobox.idee h4 { color: #7a5600; }

/* Aufklapper */
details.mehr {
  border: 1px solid var(--linie); border-radius: var(--radius); background: #fff;
  margin: 10px 0;
}
details.mehr > summary {
  cursor: pointer; padding: 12px 16px; font-weight: 600; list-style: none;
  display: flex; align-items: center; gap: 10px;
}
details.mehr > summary::-webkit-details-marker { display: none; }
details.mehr > summary::before {
  content: ""; width: 8px; height: 8px; flex: none;
  border-right: 2px solid var(--tinte-2); border-bottom: 2px solid var(--tinte-2);
  transform: rotate(-45deg); transition: transform .2s;
}
details.mehr[open] > summary::before { transform: rotate(45deg); }
details.mehr > summary .tag { margin-left: auto; }
details.mehr .inhalt { padding: 0 16px 16px 34px; }
.tag {
  font-size: .72rem; font-weight: 700; letter-spacing: .03em; text-transform: uppercase;
  padding: 2px 8px; border-radius: 999px; background: var(--flaeche-2); color: var(--tinte-2);
}
.tag.normal { text-transform: none; letter-spacing: 0; }
.tag.numerik { background: #ece9fb; color: #4a3aa7; }
.tag.code { background: #e4f3e8; color: var(--gut); }

/* Formeln */
.formel {
  overflow-x: auto; overflow-y: hidden; padding: 6px 2px; margin: 8px 0;
}
.formel .katex-display { margin: .4em 0; }
.term { border-radius: 4px; transition: background .2s, box-shadow .2s; }
.term.hell { background: #fff1b8; box-shadow: 0 0 0 3px #fff1b8; }
.chips { display: flex; flex-wrap: wrap; gap: 8px; margin: 10px 0; }
.chip {
  font: inherit; font-size: .85rem; cursor: pointer; padding: 5px 12px; border-radius: 999px;
  border: 1px solid var(--linie-stark); background: #fff; color: var(--tinte);
}
.chip:hover { border-color: var(--akzent); }
.chip[aria-pressed="true"] { background: var(--akzent); border-color: var(--akzent); color: #fff; }
.erklaerung {
  min-height: 3.2em; padding: 10px 14px; border-radius: var(--radius-klein);
  background: var(--flaeche-2); font-size: .95rem; color: var(--tinte-2);
}

/* Code */
pre.code {
  font: 13px/1.55 var(--mono); background: #1f1f1e; color: #e8e6e1;
  border-radius: var(--radius); padding: 14px 0; overflow-x: auto; margin: 10px 0;
}
pre.code .z { display: block; padding: 0 16px; border-left: 3px solid transparent; transition: background .2s; }
pre.code .z.hell { background: rgba(255, 210, 80, .18); border-left-color: #ffd250; }
pre.code .k { color: #8e8b84; }
pre.code .s { color: #f0b37e; }
code { font-family: var(--mono); font-size: .88em; background: var(--flaeche-2); padding: 1px 5px; border-radius: 4px; }
.pfad { font-family: var(--mono); font-size: .8rem; color: var(--tinte-2); }

/* Interaktive Werkzeuge */
.werkzeug {
  background: #fff; border: 1px solid var(--linie); border-radius: 14px;
  padding: 20px; margin: 24px 0; box-shadow: var(--schatten);
}
.werkzeug-kopf { display: flex; align-items: baseline; gap: 10px; flex-wrap: wrap; margin-bottom: 12px; }
.werkzeug-kopf h3 { margin: 0; }
.werkzeug-kopf .tag { background: var(--akzent-hell); color: var(--akzent-dunkel); }
.regler { display: grid; grid-template-columns: auto 1fr auto; align-items: center; gap: 12px; margin: 10px 0; }
.regler label { font-size: .9rem; color: var(--tinte-2); white-space: nowrap; }
.regler output { font-variant-numeric: tabular-nums; font-weight: 600; min-width: 5.5em; text-align: right; }
input[type="range"] { width: 100%; accent-color: var(--akzent); }
.regler.zeitregler { flex: 1; margin: 0; min-width: 240px; }
@media (max-width: 520px) {
  .regler { grid-template-columns: 1fr auto; gap: 4px 12px; }
  .regler label { grid-column: 1 / -1; white-space: normal; }
}
.umschalter { display: inline-flex; border: 1px solid var(--linie-stark); border-radius: 999px; padding: 3px; background: var(--flaeche-2); flex-wrap: wrap; }
.umschalter button {
  font: inherit; font-size: .88rem; border: 0; background: transparent; padding: 6px 14px;
  border-radius: 999px; cursor: pointer; color: var(--tinte-2);
}
.umschalter button[aria-pressed="true"] { background: #fff; color: var(--tinte); box-shadow: var(--schatten); font-weight: 600; }
.knopfreihe { display: flex; gap: 8px; flex-wrap: wrap; align-items: center; margin: 10px 0; }

/* Diagramme */
.diagramm { width: 100%; height: auto; overflow: visible; font-family: var(--schrift); font-size: 12px; fill: var(--tinte-2); }
.diagramm .achse line, .diagramm .achse path { stroke: var(--linie-stark); }
.diagramm .gitter line { stroke: var(--flaeche-3); stroke-width: 1; }
.diagramm .titel { fill: var(--tinte); font-weight: 600; }
.legende { display: flex; flex-wrap: wrap; gap: 14px; font-size: .85rem; color: var(--tinte-2); margin: 6px 0; }
.legende > span { display: inline-flex; align-items: center; gap: 6px; }
.diagramm .halo { paint-order: stroke; stroke: #fff; stroke-width: 4px; stroke-linejoin: round; }
.legende i { display: inline-block; width: 18px; height: 0; border-top: 2.5px solid; }
.legende i.punkt { width: 9px; height: 9px; border: 0; border-radius: 50%; }
.legende i.gestrichelt { border-top-style: dashed; }
.tooltip {
  position: absolute; pointer-events: none; z-index: 5;
  background: #fff; border: 1px solid var(--linie); border-radius: 8px; box-shadow: var(--schatten);
  padding: 8px 10px; font-size: .8rem; line-height: 1.45; color: var(--tinte); white-space: nowrap;
  opacity: 0; transition: opacity .12s;
}
.tooltip.an { opacity: 1; }
.tooltip b { font-weight: 600; }
.tooltip i { display: inline-block; width: 8px; height: 8px; border-radius: 50%; margin-right: 6px; }
.diagramm-huelle { position: relative; }

/* ---------------------------------------------------------------- Start */
.held { display: grid; grid-template-columns: 1fr 1fr; gap: 32px; align-items: center; margin: 12px 0 40px; }
.held .lead { font-size: 1.2rem; }
.held .knopfreihe { margin-top: 20px; }
@media (max-width: 820px) { .held { grid-template-columns: 1fr; } }
.skalen { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; position: relative; }
@media (max-width: 720px) { .skalen { grid-template-columns: 1fr; } }
.skala {
  display: block; text-decoration: none; color: inherit; background: #fff; border: 1px solid var(--linie);
  border-radius: 14px; overflow: hidden; box-shadow: var(--schatten); transition: transform .2s, box-shadow .2s, border-color .2s;
}
.skala:hover { transform: translateY(-3px); border-color: var(--akzent); box-shadow: 0 8px 24px rgba(0, 100, 168, .14); color: inherit; }
.skala svg { display: block; width: 100%; height: auto; background: var(--flaeche-2); }
.skala .skala-text { padding: 14px 16px 16px; }
.skala .groesse { font-size: .78rem; font-weight: 700; color: var(--akzent); letter-spacing: .04em; text-transform: uppercase; }
.skala h3 { margin: 4px 0 6px; font-size: 1.08rem; }
.skala p { font-size: .9rem; color: var(--tinte-2); margin: 0; }
.skala .weiter { display: inline-block; margin-top: 10px; font-size: .85rem; font-weight: 600; color: var(--akzent); }
.so-gehts { display: grid; grid-template-columns: repeat(auto-fit, minmax(190px, 1fr)); gap: 12px; margin-top: 16px; }
.so-gehts div { display: flex; gap: 10px; align-items: flex-start; font-size: .9rem; color: var(--tinte-2); }
.so-gehts svg { flex: none; color: var(--akzent); }
.so-gehts b { color: var(--tinte); display: block; }

/* ---------------------------------------------------------------- Kapitel 1 */
.reiter { display: flex; gap: 4px; border-bottom: 1px solid var(--linie); margin: 24px 0 0; flex-wrap: wrap; }
.reiter button {
  font: inherit; font-weight: 600; background: none; border: 0; cursor: pointer;
  padding: 10px 16px; color: var(--tinte-2); border-bottom: 3px solid transparent; margin-bottom: -1px;
}
.reiter button[aria-selected="true"] { color: var(--akzent); border-bottom-color: var(--akzent); }
.reiter-inhalt { padding-top: 20px; }
.reiter-inhalt[hidden] { display: none; }
.hotspot-bild { position: relative; }
.hotspot {
  position: absolute; width: 30px; height: 30px; margin: -15px 0 0 -15px; border-radius: 50%;
  border: 3px solid #fff; background: var(--akzent); color: #fff; font-weight: 700; font-size: .85rem;
  cursor: pointer; box-shadow: 0 0 0 0 rgba(0, 100, 168, .6); animation: puls 2s infinite;
}
.hotspot[aria-expanded="true"] { background: var(--orange); animation: none; }
@keyframes puls { 0% { box-shadow: 0 0 0 0 rgba(0, 100, 168, .55); } 70% { box-shadow: 0 0 0 14px rgba(0, 100, 168, 0); } 100% { box-shadow: 0 0 0 0 rgba(0, 100, 168, 0); } }
@media (prefers-reduced-motion: reduce) { .hotspot { animation: none; } .js .kapitel.aktiv { animation: none; } }
.hotspot-text { min-height: 5em; }

/* ---------------------------------------------------------------- Flussdiagramm (Kap. 4) */
.fluss { display: grid; grid-template-columns: 1fr; gap: 0; max-width: 420px; margin: 0 auto; }
.fluss-box {
  font: inherit; text-align: left; cursor: pointer; background: #fff; border: 2px solid var(--linie-stark);
  border-radius: 12px; padding: 10px 14px; transition: border-color .15s, background .15s;
}
.fluss-box:hover { border-color: var(--akzent); }
.fluss-box[aria-pressed="true"] { border-color: var(--akzent); background: var(--akzent-hell); }
.fluss-box b { display: block; font-size: .95rem; }
.fluss-box span { font-size: .82rem; color: var(--tinte-2); }
.fluss-pfeil { height: 26px; display: grid; place-items: center; color: var(--tinte-3); }
.fluss-gabel { display: grid; grid-template-columns: 1fr 1fr; gap: 10px; }
.fluss-box.raute { text-align: center; border-style: dashed; }
.fluss-box.ende { text-align: center; background: var(--flaeche-2); }

/* ---------------------------------------------------------------- Quiz */
.frage { margin: 0 0 18px; }
.frage h4 { margin: 0 0 10px; font-size: 1.02rem; }
.frage .nr { color: var(--akzent); margin-right: 6px; }
.antworten { display: grid; gap: 8px; }
.antwort {
  font: inherit; text-align: left; cursor: pointer; padding: 10px 14px; border-radius: 8px;
  border: 1px solid var(--linie-stark); background: #fff; display: flex; gap: 10px; align-items: flex-start;
}
.antwort:hover:not([disabled]) { border-color: var(--akzent); background: var(--flaeche-2); }
.antwort .marker { flex: none; width: 22px; height: 22px; border-radius: 50%; border: 2px solid var(--linie-stark); display: grid; place-items: center; font-size: .8rem; font-weight: 700; }
.antwort.richtig { border-color: var(--gut); background: var(--gut-hell); }
.antwort.richtig .marker { border-color: var(--gut); background: var(--gut); color: #fff; }
.antwort.falsch { border-color: var(--schlecht); background: var(--schlecht-hell); }
.antwort.falsch .marker { border-color: var(--schlecht); background: var(--schlecht); color: #fff; }
.antwort[disabled] { cursor: default; }
.rueckmeldung { margin-top: 10px; font-size: .92rem; padding: 10px 14px; border-radius: 8px; background: var(--flaeche-2); }
.rueckmeldung[hidden] { display: none; }
.ergebnis { text-align: center; padding: 28px 20px; }
.ergebnis .gross { font-size: 3rem; font-weight: 700; color: var(--akzent); line-height: 1; }

/* ---------------------------------------------------------------- Fuß */
.foerderung { display: flex; gap: 20px; align-items: center; flex-wrap: wrap; margin-top: 32px; padding-top: 20px; border-top: 1px solid var(--linie); }
.foerderung img { width: 360px; max-width: 100%; }
.literatur { font-size: .88rem; color: var(--tinte-2); padding-left: 1.2em; }
.literatur li { margin-bottom: 6px; }
.team { columns: 2 240px; font-size: .92rem; color: var(--tinte-2); padding-left: 1.2em; }