:root {
  --zemin: #1b1e22;
  --mavi: #00559d;
  --mavi-ustu: #1468b0;
  --yesil: #54bd25;
  --koyu: #12350a;
  --kagit: #fff;
  --sw: 360px;   /* sayfa genişliği (JS ayarlar) */
  --sh: 509px;   /* sayfa yüksekliği (JS ayarlar) */
  --sure: 700ms; /* çevirme süresi (JS ayarlar) */
  --egri: cubic-bezier(.45, .05, .25, 1);
}

*, *::before, *::after { box-sizing: border-box; }

html, body {
  height: 100%;
  margin: 0;
  overflow: hidden;
  overscroll-behavior: none;
}

body {
  position: fixed;
  inset: 0;
  width: 100%;
  background:
    radial-gradient(ellipse at 50% 40%, #2c3138 0%, var(--zemin) 62%, #101214 100%);
  color: #fff;
  font: 16px/1.4 system-ui, -apple-system, "Segoe UI", Roboto, Arial, sans-serif;
}

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

.kt-logo {
  position: fixed;
  z-index: 30;
  top: 16px;
  left: 50%;
  height: 56px;
  width: auto;
  max-width: calc(100% - 32px);
  padding: 8px 18px;
  background: #fff;
  border-radius: 12px;
  box-shadow: 0 8px 22px rgba(0, 0, 0, .28);
  transform: translateX(-50%);
  pointer-events: none;
}

/* Sahne: logo şeridi ve alt çubuk hariç */
.kt-sahne {
  position: fixed;
  inset: 104px 0 var(--alt, 88px) 0;
  display: grid;
  place-items: center;
  overflow: hidden;
  touch-action: none;
}

.kt-sahne.kt-yakin {
  display: block;
  overflow: auto;
  touch-action: pan-x pan-y;
  scrollbar-width: none;
  cursor: grab;
}

.kt-sahne.kt-yakin::-webkit-scrollbar { width: 0; height: 0; }

.kt-sahne.kt-yakin .kt-yuz { cursor: grab; }

.kt-sahne.kt-surukleniyor,
.kt-sahne.kt-surukleniyor .kt-yuz {
  cursor: grabbing;
}

.kt-sahne.kt-yakin .kt-kitap {
  margin: 28px auto;
}

/* Kitap: iki sayfa genişliğinde, ortası sırt */
.kt-kitap {
  position: relative;
  width: calc(var(--sw) * 2);
  height: var(--sh);
  perspective: 2600px;
  transition: transform var(--sure) var(--egri);
  box-shadow: 0 24px 60px rgba(0, 0, 0, .35);
}

.kt-kitap.kt-tek,
.kt-kitap.kt-tek.kt-bas,
.kt-kitap.kt-tek.kt-son {
  width: var(--sw);
  overflow: hidden;
  transform: none;
}

.kt-kart {
  position: absolute;
  inset: 0;
  background: var(--kagit);
  cursor: pointer;
  transition: transform var(--sure) var(--egri);
}

.kt-kart.kt-cevrik { transform: translateX(-105%); }

.kt-kart canvas {
  display: block;
  width: 100%;
  height: 100%;
  pointer-events: none;
}
.kt-kitap.kt-bas { transform: translateX(calc(var(--sw) * -.5)); }
.kt-kitap.kt-son { transform: translateX(calc(var(--sw) * .5)); }

/* Yaprak: iki yüzlü kâğıt, sırttan döner */
.kt-yaprak {
  position: absolute;
  top: 0;
  left: 50%;
  width: var(--sw);
  height: 100%;
  transform-origin: left center;
  transform-style: preserve-3d;
  transition: transform var(--sure) var(--egri);
  will-change: transform;
}

.kt-yaprak.kt-cevrik { transform: rotateY(-180deg); }

.kt-yuz {
  position: absolute;
  inset: 0;
  overflow: hidden;
  background: var(--kagit);
  backface-visibility: hidden;
  -webkit-backface-visibility: hidden;
  cursor: pointer;
}

.kt-arka { transform: rotateY(180deg); }

.kt-yuz canvas {
  display: block;
  width: 100%;
  height: 100%;
  pointer-events: none;
}

/* Sırt gölgesi */
.kt-yuz::after {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
}
.kt-on::after   { background: linear-gradient(to right, rgba(0, 0, 0, .2), rgba(0, 0, 0, 0) 7%); }
.kt-arka::after { background: linear-gradient(to left,  rgba(0, 0, 0, .2), rgba(0, 0, 0, 0) 7%); }

.kt-bos { box-shadow: none; cursor: default; }

/* Alt çubuk */
.kt-alt {
  position: fixed;
  left: 0;
  right: 0;
  bottom: 0;
  z-index: 40;
  padding: 16px 18px 20px;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-wrap: wrap;
  gap: 10px;
}

.kt-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 40px;
  padding: 0 18px;
  border: 1px solid var(--mavi);
  border-radius: 999px;
  background: var(--mavi);
  color: #fff;
  font: inherit;
  font-size: 15px;
  font-weight: 600;
  line-height: 1;
  text-decoration: none;
  cursor: pointer;
  transition: background .15s ease, border-color .15s ease;
}

.kt-btn:hover {
  background: var(--mavi-ustu);
  border-color: var(--mavi-ustu);
}

.kt-btn[disabled] {
  opacity: .38;
  cursor: default;
}

.kt-btn[disabled]:hover {
  background: var(--mavi);
  border-color: var(--mavi);
}

.kt-sayac {
  min-width: 7.2rem;
  min-height: 40px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  color: #fff;
}

.kt-yuzde { min-width: 4.2rem; }

.kt-zoom {
  min-width: 42px;
  padding: 0;
  font-size: 20px;
}

.kt-kir { display: none; }

*:focus,
*:focus-visible {
  outline: none;
}

@media (max-width: 800px) {
  .kt-sahne { inset: 72px 0 var(--alt, 88px) 0; place-items: start center; padding-top: 6px; }
  .kt-logo { top: 8px; height: 42px; padding: 6px 14px; border-radius: 10px; }
  .kt-alt {
    flex-wrap: wrap;
    gap: 8px;
    padding: 10px 10px calc(10px + env(safe-area-inset-bottom));
  }
  .kt-kir { display: block; flex-basis: 100%; height: 0; }
  .kt-btn { min-height: 36px; padding: 0 12px; font-size: 13px; }
  .kt-sayac { min-width: 0; min-height: 36px; font-size: 13px; }
  .kt-yuzde { min-width: 3rem; }
  .kt-zoom { min-width: 36px; font-size: 18px; }
  #ktTam { display: none; }
}