:root {
  color-scheme: dark;
  --bg: #2f3440;
  --panel: #1d212a;
  --panel-2: #252a35;
  --text: #f5f7fb;
  --muted: #aeb6c7;
  --accent: #d92745;
  --border: rgba(255, 255, 255, 0.12);
}

* {
  box-sizing: border-box;
}

html,
body {
  width: 100%;
  height: 100%;
  margin: 0;
  overflow: hidden;
  background: var(--bg);
  font-family: Arial, Helvetica, sans-serif;
}

button,
a {
  font: inherit;
}

.catalog-shell {
  display: grid;
  grid-template-rows: 44px minmax(0, 1fr) 48px;
  width: 100%;
  height: 100%;
  background:
    radial-gradient(circle at 50% 30%, rgba(255, 255, 255, 0.08), transparent 40%),
    var(--bg);
}

.catalog-header,
.catalog-toolbar {
  z-index: 10;
  display: flex;
  align-items: center;
  padding: 0 18px;
  background: rgba(29, 33, 42, 0.96);
  border-color: var(--border);
  backdrop-filter: blur(8px);
}

.catalog-header {
  justify-content: space-between;
  border-bottom: 1px solid var(--border);
}

.brand {
  color: var(--text);
  font-size: 19px;
  font-weight: 700;
  letter-spacing: 0.04em;
}

.catalog-title {
  overflow: hidden;
  color: var(--muted);
  font-size: 14px;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.catalog-stage {
  position: relative;
  display: grid;
  place-items: center;
  min-height: 0;
  padding: 8px 20px;
}

#book {
  width: 100%;
  /*
   * PageFlip, otomatik boyutta kitabı yalnızca genişliğe göre büyütür.
   * Aşağıdaki sınır A4 çift sayfa oranını kullanarak kitabı kullanılabilir
   * ekran yüksekliğine sığdırır; sayfa çevirme yapısına dokunmaz.
   */
  max-width: calc((100vh - 108px) * 1.4143) !important;
  max-width: calc((100dvh - 108px) * 1.4143) !important;
  opacity: 0;
  transition: opacity 180ms ease;
}

#book.ready {
  opacity: 1;
}

.book-frame {
  display: grid;
  place-items: center;
  width: 100%;
  height: 100%;
  min-height: 0;
}

:fullscreen .book-frame {
  width: 100%;
  height: 100%;
}

.catalog-page {
  background: #fff;
  overflow: hidden;
}

.catalog-page canvas {
  display: block;
  width: 100%;
  height: 100%;
}

.loading {
  position: absolute;
  inset: 0;
  z-index: 5;
  display: grid;
  place-content: center;
  gap: 14px;
  text-align: center;
  color: var(--text);
  background: var(--bg);
}

.loading[hidden] {
  display: none;
}

.spinner {
  width: 42px;
  height: 42px;
  margin: 0 auto;
  border: 4px solid rgba(255, 255, 255, 0.2);
  border-top-color: var(--accent);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}

@keyframes spin {
  to {
    transform: rotate(360deg);
  }
}

.catalog-toolbar {
  justify-content: center;
  gap: 10px;
  border-top: 1px solid var(--border);
}

.tool-button,
.download-link {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 42px;
  height: 38px;
  padding: 0 13px;
  color: var(--text);
  text-decoration: none;
  background: var(--panel-2);
  border: 1px solid var(--border);
  border-radius: 8px;
  cursor: pointer;
  transition: background 150ms ease, border-color 150ms ease;
}

.tool-button:hover,
.download-link:hover {
  background: #343b49;
  border-color: rgba(255, 255, 255, 0.24);
}

.tool-button:disabled {
  opacity: 0.42;
  cursor: default;
}

.page-status {
  min-width: 82px;
  color: var(--text);
  font-variant-numeric: tabular-nums;
  text-align: center;
}

.error-message {
  max-width: 560px;
  padding: 20px;
  color: #fff;
  background: #8c2435;
  border-radius: 10px;
}

@media (max-width: 640px) {
  .catalog-shell {
    grid-template-rows: 48px minmax(0, 1fr) 54px;
  }

  .catalog-header {
    padding: 0 12px;
  }

  .catalog-title {
    max-width: 52vw;
    font-size: 12px;
  }

  .catalog-stage {
    padding: 10px 5px;
  }

  #book {
    /* Dar ekranda tek sayfa oranı kullanılır. */
    max-width: calc((100vh - 122px) * 0.7071) !important;
    max-width: calc((100dvh - 122px) * 0.7071) !important;
  }

  .catalog-toolbar {
    gap: 6px;
    padding: 0 6px;
  }

  .tool-button,
  .download-link {
    min-width: 38px;
    height: 36px;
    padding: 0 10px;
  }

  .download-text,
  .fullscreen-text {
    display: none;
  }
}