/* Blätter-Reader Saisonheft SC Niestetal
   Farben und Formen nach design/stilvorlage.md: Dunkelblau, Gelb, Weiß, Ecken 6 px, Schrift 900 in Großbuchstaben.
   Keine Schriften, Bilder oder Skripte von außen. */

:root {
  --scn-blue: #08294c;
  --scn-blue-dark: #041933;
  --scn-yellow: #ffcc18;
  --scn-light: #f5f7fa;
  --dur: .9s;
  --leaf-ease: cubic-bezier(.65, 0, .35, 1); /* langsam am Anfang und Ende, schnell durch die Senkrechte; gleiche Kurve steuert die Abdunklung (reader.js, EASE) */
  --pw: 300px;
  --ph: 424px;
}

* { box-sizing: border-box; }

html, body {
  height: 100%;
  margin: 0;
  overflow: hidden;
  background: var(--scn-blue-dark);
  color: #fff;
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}

.app {
  display: flex;
  flex-direction: column;
  height: 100vh;
  height: 100dvh;
  width: 100%;
  overflow: hidden;
}

/* Kopf */
.top {
  flex: none;
  display: flex;
  align-items: baseline;
  gap: .8rem;
  padding: .55rem 1rem;
  background: linear-gradient(90deg, #193866, #353775);
  border-bottom: 3px solid var(--scn-yellow);
}
.top .kicker {
  margin: 0;
  color: var(--scn-yellow);
  font-size: .8rem;
  font-weight: 900;
  letter-spacing: .1em;
  text-transform: uppercase;
}
.top h1 {
  margin: 0;
  font-size: 1.25rem;
  font-weight: 900;
  line-height: 1;
  letter-spacing: -.02em;
  text-transform: uppercase;
}

/* Lesefläche */
.viewport {
  flex: 1 1 auto;
  min-height: 0;
  position: relative;
  overflow: hidden;
  overflow: clip; /* ohne Zoom nie scrollen: sonst erzeugt die Verschiebung der Doppelseite am Heftende eine Bildlaufleiste und das Heft springt */
  display: flex;
  background: radial-gradient(ellipse at 50% 40%, #0d3a69 0%, var(--scn-blue) 45%, var(--scn-blue-dark) 100%);
  touch-action: pan-y pinch-zoom;
  overscroll-behavior: contain;
  outline-offset: -4px;
}
.viewport.zoomed { overflow: auto; touch-action: pan-x pan-y; cursor: grab; }
.viewport.panning { cursor: grabbing; }
/* Bühne wird nur per Skript fokussiert (tabindex -1), kein Rahmen; Knöpfe behalten ihren Fokus */
.viewport:focus, .viewport:focus-visible { outline: none; }

.book {
  position: relative;
  flex: none;
  margin: auto;
  width: calc(var(--pw) * 2);
  height: var(--ph);
  perspective: calc(var(--pw) * 11);
  user-select: none;
  -webkit-user-select: none;
}
.book.single { width: var(--pw); overflow: hidden; overflow: clip; } /* Handy: nichts vom Blatt ausserhalb des Buchs zeigen */
.book.nolayout, .book.nolayout * { transition: none !important; }

.shifter {
  position: absolute;
  inset: 0;
  transform-style: preserve-3d;
  transition: transform var(--dur) ease;
}
.book:not(.single)[data-pos="start"] .shifter,
.book:not(.single)[data-pos="start"] .edges { transform: translateX(calc(var(--pw) * -.5)); }
.book:not(.single)[data-pos="end"] .shifter,
.book:not(.single)[data-pos="end"] .edges { transform: translateX(calc(var(--pw) * .5)); }

/* Blatt: Vorderseite rechts, Rückseite erscheint links nach dem Umklappen */
.leaf {
  position: absolute;
  top: 0;
  left: 50%;
  width: 50%;
  height: 100%;
  transform-origin: left center;
  transform-style: preserve-3d;
  transition: transform var(--dur) var(--leaf-ease);
}
.book.single .leaf { left: 0; width: 100%; }
.leaf.flipped { transform: rotateY(-180deg); }
.leaf.notrans { transition: none; }
.leaf.far { visibility: hidden; }
.leaf.anim { will-change: transform; }
.book.single .leaf.flipped { visibility: hidden; transition: transform var(--dur) var(--leaf-ease), visibility 0s linear var(--dur); }
.book.single .leaf.flipped.notrans { transition: none; }

.face {
  position: absolute;
  inset: 0;
  overflow: hidden;
  background: #fff;
  backface-visibility: hidden;
  -webkit-backface-visibility: hidden;
  box-shadow: 0 3px 14px rgba(0, 0, 0, .35);
}
.face.back { transform: rotateY(180deg); }
.face img {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: fill;
  -webkit-user-drag: none;
  user-select: none;
  pointer-events: none;
}
/* Falz in der Mitte */
.face.front::after, .face.back::after {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
}
.face.front::after { background: linear-gradient(to right, rgba(0, 0, 0, .30), rgba(0, 0, 0, 0) 7%); }
.face.back::after { background: linear-gradient(to left, rgba(0, 0, 0, .30), rgba(0, 0, 0, 0) 7%); }
/* Rückseite eines Einzelblatts am Handy: leeres Papier */
.face.blank { background: linear-gradient(to left, #e9edf2, #f8f9fb); }

/* Abdunklung beim Klappen: Deckkraft wird per Web Animations API synchron zur Drehung gesteuert (reader.js).
   Ruhezustand: unsichtbar. */
.shade {
  position: absolute;
  inset: 0;
  z-index: 3;
  pointer-events: none;
  opacity: 0;
  background: #070a12; /* gleichmäßig, kein Verlauf zur Bindung (kein dickes dunkles Band) */
}
/* Am drehenden Blatt den Falzschatten ausblenden; nach dem Ende weich einblenden (kein Nachdunkeln) */
.face.front::after, .face.back::after { transition: opacity .2s ease; }
.leaf.anim .face::after { opacity: 0; transition: none; }

/* Randflächen zum Blättern per Klick */
.edges {
  position: absolute;
  inset: 0;
  z-index: 2000;
  pointer-events: none;
  transition: transform var(--dur) ease;
}
.edge {
  position: absolute;
  top: 0;
  bottom: 0;
  width: calc(var(--pw) * .2);
  margin: 0;
  padding: 0;
  border: 0;
  background: transparent;
  color: var(--scn-yellow);
  font: inherit;
  font-size: 3rem;
  font-weight: 900;
  line-height: 1;
  cursor: pointer;
  pointer-events: auto;
  opacity: 0;
  transition: opacity .2s;
  display: flex;
  align-items: center;
}
.book.single .edge { width: calc(var(--pw) * .25); }
.edge-prev { left: 0; justify-content: flex-start; padding-left: .3rem; background: linear-gradient(to right, rgba(4, 25, 51, .45), rgba(4, 25, 51, 0)); }
.edge-next { right: 0; justify-content: flex-end; padding-right: .3rem; background: linear-gradient(to left, rgba(4, 25, 51, .45), rgba(4, 25, 51, 0)); }
.edge:hover, .edge:focus-visible { opacity: 1; }
.edge[hidden] { display: none; }
.viewport.zoomed .edge { pointer-events: none; opacity: 0; }
@media (hover: none) {
  .edge { opacity: 0; }
  .edge:hover { opacity: 0; }
}

/* Leiste unten */
.bar {
  flex: none;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: center;
  gap: .5rem;
  padding: .55rem .75rem;
  background: var(--scn-blue-dark);
  border-top: 1px solid rgba(255, 255, 255, .15);
}
.btn {
  min-height: 44px;
  padding: .5rem 1rem;
  border: 2px solid var(--scn-yellow);
  border-radius: 6px;
  background: var(--scn-yellow);
  color: var(--scn-blue);
  font: inherit;
  font-size: .8rem;
  font-weight: 900;
  letter-spacing: .05em;
  text-transform: uppercase;
  cursor: pointer;
}
.btn.ghost { background: transparent; color: #fff; border-color: rgba(255, 255, 255, .6); }
.btn:hover:not(:disabled) { transform: translateY(-1px); box-shadow: 0 6px 16px rgba(0, 0, 0, .35); }
.btn.ghost:hover:not(:disabled) { border-color: var(--scn-yellow); color: var(--scn-yellow); }
.btn:disabled { opacity: .4; cursor: default; }
.btn:focus-visible, .edge:focus-visible, .jump input:focus-visible, .thumb:focus-visible { outline: 3px solid #fff; outline-offset: 2px; }

.jump {
  display: flex;
  align-items: center;
  gap: .45rem;
  margin: 0;
  font-size: .85rem;
  font-weight: 700;
}
.jump label { font-weight: 900; text-transform: uppercase; letter-spacing: .05em; font-size: .8rem; }
.jump input {
  width: 4.2rem;
  min-height: 44px;
  padding: 0 .4rem;
  border: 2px solid rgba(255, 255, 255, .6);
  border-radius: 6px;
  background: #fff;
  color: var(--scn-blue);
  font: inherit;
  font-weight: 900;
  text-align: center;
}
.jump .of { white-space: nowrap; color: rgba(255, 255, 255, .85); }

.status {
  position: absolute;
  width: 1px;
  height: 1px;
  margin: -1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
}

/* Übersicht */
.overview {
  width: min(960px, 94vw);
  max-height: 88vh;
  padding: 0;
  border: 0;
  border-radius: 14px;
  background: var(--scn-blue);
  color: #fff;
  box-shadow: 0 15px 35px rgba(4, 25, 51, .6);
}
.overview::backdrop { background: rgba(4, 25, 51, .8); }
.overview-head {
  position: sticky;
  top: 0;
  z-index: 1;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: .8rem 1rem;
  background: var(--scn-blue);
  border-bottom: 3px solid var(--scn-yellow);
}
.overview-head h2 { margin: 0; font-size: 1.2rem; font-weight: 900; text-transform: uppercase; }
.grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(104px, 1fr));
  gap: .8rem;
  padding: 1rem;
}
.thumb {
  display: block;
  padding: .3rem;
  border: 2px solid transparent;
  border-radius: 6px;
  background: transparent;
  color: #fff;
  font: inherit;
  font-size: .8rem;
  font-weight: 700;
  text-align: center;
  cursor: pointer;
}
.thumb img { display: block; width: 100%; height: auto; aspect-ratio: 400 / 566; background: #fff; border-radius: 2px; }
.thumb span { display: block; margin-top: .25rem; }
.thumb:hover { border-color: var(--scn-yellow); }
.thumb[aria-current="true"] { border-color: var(--scn-yellow); background: rgba(255, 204, 24, .18); }

.noscript { padding: 2rem; text-align: center; }

/* Schmales Fenster */
@media (max-width: 600px) {
  .top { padding: .4rem .8rem; }
  .top h1 { font-size: 1.05rem; }
  .bar { gap: .4rem; padding: .45rem .5rem; }
  .btn { padding: .4rem .6rem; font-size: .72rem; min-height: 44px; }
  #btn-prev, #btn-next { flex: 1 1 0; }
  .jump { order: 3; width: 100%; justify-content: center; }
  .jump input { width: 3.6rem; }
}

/* Bewegung reduzieren */
@media (prefers-reduced-motion: reduce) {
  .shifter, .edges, .leaf, .book.single .leaf.flipped, .edge, .btn { transition: none !important; }
  .btn:hover:not(:disabled) { transform: none; }
  .shade { display: none; }
}