:root {
  --viewer-bg: #2b2e36;
  --viewer-panel: #1f222a;
  --viewer-text: #e8eaed;
  --viewer-muted: #a0a6b1;
  --viewer-border: #3a3e47;
  --viewer-accent: #5aa9ff;
  --sidebar-w: 260px;
}

html, body {
  margin: 0;
  padding: 0;
  height: 100%;
  background: var(--viewer-bg);
  color: var(--viewer-text);
  overflow: hidden;
  font-family: -apple-system, BlinkMacSystemFont, "Apple SD Gothic Neo",
               "Malgun Gothic", "Noto Sans KR", sans-serif;
}

.viewer-app {
  display: grid;
  grid-template-rows: 48px 1fr;
  grid-template-columns: var(--sidebar-w) 1fr;
  grid-template-areas: "toolbar toolbar" "sidebar stage";
  height: 100vh;
}

.viewer-toolbar {
  grid-area: toolbar;
  background: var(--viewer-panel);
  border-bottom: 1px solid var(--viewer-border);
  display: flex;
  align-items: center;
  padding: 0 12px;
  gap: 8px;
  z-index: 10;
}

.viewer-toolbar .title {
  flex: 1;
  font-size: 14px;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  color: var(--viewer-text);
}

.viewer-toolbar button,
.viewer-toolbar input[type=text],
.viewer-toolbar input[type=number] {
  background: #33373f;
  color: var(--viewer-text);
  border: 1px solid var(--viewer-border);
  border-radius: 6px;
  padding: 6px 10px;
  font-size: 13px;
  cursor: pointer;
  font-family: inherit;
}
.viewer-toolbar button:hover { background: #40454e; }
.viewer-toolbar button.active { background: var(--viewer-accent); color: #fff; border-color: var(--viewer-accent); }
.viewer-toolbar button:disabled { opacity: 0.4; cursor: not-allowed; }

.viewer-toolbar .page-indicator {
  padding: 0 8px;
  font-size: 13px;
  color: var(--viewer-muted);
}
.viewer-toolbar .page-indicator input {
  width: 54px;
  text-align: center;
  margin-right: 4px;
}

.viewer-toolbar .search-wrap {
  display: flex;
  align-items: center;
  gap: 4px;
}
.viewer-toolbar .search-wrap input { width: 160px; }
.viewer-toolbar .search-info { font-size: 12px; color: var(--viewer-muted); min-width: 50px; text-align: center; }

.viewer-sidebar {
  grid-area: sidebar;
  background: var(--viewer-panel);
  border-right: 1px solid var(--viewer-border);
  overflow-y: auto;
  transition: margin-left 0.2s;
}
.viewer-app.sidebar-collapsed .viewer-sidebar { margin-left: calc(-1 * var(--sidebar-w)); }
.viewer-app.sidebar-collapsed { grid-template-columns: 0 1fr; }

.sidebar-tabs {
  display: flex;
  border-bottom: 1px solid var(--viewer-border);
  background: #1a1d24;
  position: sticky;
  top: 0;
  z-index: 2;
}
.sidebar-tabs button {
  flex: 1;
  background: transparent;
  border: 0;
  color: var(--viewer-muted);
  padding: 10px;
  font-size: 13px;
  cursor: pointer;
  border-bottom: 2px solid transparent;
}
.sidebar-tabs button.active { color: var(--viewer-text); border-bottom-color: var(--viewer-accent); }

.sidebar-panel { padding: 10px; display: none; }
.sidebar-panel.active { display: block; }

.thumb {
  cursor: pointer;
  margin-bottom: 10px;
  border: 2px solid transparent;
  border-radius: 6px;
  overflow: hidden;
  background: #15171d;
  transition: border-color 0.15s;
}
.thumb:hover { border-color: #4b525d; }
.thumb.current { border-color: var(--viewer-accent); }
.thumb canvas { width: 100%; height: auto; display: block; }
.thumb .label {
  padding: 4px 6px;
  font-size: 11px;
  color: var(--viewer-muted);
  text-align: center;
}

.bookmark-list { list-style: none; margin: 0; padding: 0; }
.bookmark-list li {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 8px 10px;
  border-radius: 6px;
  cursor: pointer;
  font-size: 13px;
}
.bookmark-list li:hover { background: #2a2e36; }
.bookmark-list .remove {
  background: transparent;
  border: 0;
  color: var(--viewer-muted);
  cursor: pointer;
  padding: 2px 6px;
  border-radius: 4px;
}
.bookmark-list .remove:hover { color: #ff7f7f; background: #3a3e47; }

.viewer-stage {
  grid-area: stage;
  position: relative;
  overflow: auto;
  background: var(--viewer-bg);
  display: flex;
  /* safe: 콘텐츠가 무대보다 커지면 중앙정렬 대신 시작점 정렬 → 넘친 부분도 스크롤 가능 */
  align-items: safe center;
  justify-content: safe center;
}
/* 확대(>100%) 상태: 드래그로 화면 이동(팬) */
.viewer-stage.zoomed { cursor: grab; }
.viewer-stage.zoomed.panning { cursor: grabbing; }
.viewer-stage.panning { user-select: none; }

#flip-book {
  flex-shrink: 0;
  /* flex의 justify-content:center + align-items:center 가 중앙 정렬 담당 */
  touch-action: pan-y;
}

/* 좌우 가장자리 페이지 이동 버튼 */
.edge-nav {
  position: absolute;
  top: 50%;
  transform: translateY(-50%);
  width: 56px;
  height: 96px;
  background: rgba(0, 0, 0, 0.25);
  border: 0;
  border-radius: 8px;
  color: #fff;
  font-size: 42px;
  line-height: 1;
  font-weight: 300;
  cursor: pointer;
  z-index: 6;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background 0.18s, opacity 0.18s, transform 0.12s;
  opacity: 0.35;
  user-select: none;
}
.edge-nav:hover {
  background: rgba(0, 0, 0, 0.55);
  opacity: 1;
}
.edge-nav:active {
  transform: translateY(-50%) scale(0.95);
}
.edge-nav:disabled {
  opacity: 0.08;
  cursor: default;
  pointer-events: none;
}
.edge-nav-prev { left: 12px; }
.edge-nav-next { right: 12px; }

@media (max-width: 700px) {
  .edge-nav { width: 40px; height: 70px; font-size: 32px; }
}

.flip-page {
  background: #fff;
  overflow: hidden;
  position: relative;
}
.flip-page canvas {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: fill;   /* 페이지 슬롯을 꽉 채워 좌/우 흰색 여백(레터박스) 제거 */
  background: #fff;
}
.flip-page .page-num {
  position: absolute;
  bottom: 6px;
  right: 10px;
  font-size: 11px;
  color: #888;
}

.viewer-loading {
  position: absolute;
  inset: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  background: rgba(0,0,0,0.45);
  color: #fff;
  z-index: 5;
}
.viewer-loading progress { width: 260px; height: 14px; }

.empty-sidebar { padding: 20px; text-align: center; color: var(--viewer-muted); font-size: 13px; }

@media (max-width: 700px) {
  .viewer-toolbar .title { display: none; }

  /* 사이드바: 스테이지를 가리지 않도록 오버레이로 전환 (스테이지는 항상 전체 폭) */
  .viewer-app { grid-template-columns: 0 1fr; }
  .viewer-sidebar {
    position: absolute;
    top: 48px;
    left: 0;
    bottom: 0;
    width: 80%;
    max-width: 300px;
    margin-left: 0;
    z-index: 30;
    transform: translateX(0);
    transition: transform 0.25s ease;
    box-shadow: 4px 0 18px rgba(0, 0, 0, 0.5);
  }
  .viewer-app.sidebar-collapsed .viewer-sidebar {
    transform: translateX(-105%);
    margin-left: 0;
  }

  /* 툴바: 공간이 부족하므로 검색·줌·북마크를 숨기고 핵심 기능만 표시 */
  .viewer-toolbar { gap: 3px; padding: 0 6px; }
  .viewer-toolbar .search-wrap,
  #btn-zoom-out, #zoom-label, #btn-zoom-in,
  #btn-bookmark { display: none; }
  /* 버튼 글자가 두 줄로 줄바꿈되지 않도록 한 줄 고정 + 찌그러짐 방지 */
  .viewer-toolbar button,
  .viewer-toolbar .page-indicator { white-space: nowrap; flex-shrink: 0; }
  .viewer-toolbar button { padding: 6px 8px; font-size: 12px; }
  .page-indicator { padding: 0 4px; font-size: 12px; }
  .page-indicator input { width: 38px; }
}