/* ═══ TOKENS ═══ */
:root {
  --ink:       #0e1412;
  --surface:   #131a17;
  --panel:     #1a2420;
  --border:    #2a3830;
  --muted:     #3d524a;
  --dim:       #7a9489;
  --text:      #c8d8d0;
  --text-soft: #8aada0;
  --gold:      #c9a84c;
  --gold-dim:  #8a7030;
  --gold-glow: rgba(201,168,76,0.12);
  --accent:    #4a8c70;

  --radius:    6px;
  --font-serif: 'Noto Serif SC', Georgia, serif;
  --font-sans:  'Noto Sans SC', system-ui, sans-serif;
}

/* ═══ RESET ═══ */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { font-size: 16px; }
body {
  background: var(--ink);
  color: var(--text);
  font-family: var(--font-sans);
  min-height: 100dvh;
  -webkit-font-smoothing: antialiased;
}

/* ═══ HEADER ═══ */
.site-header {
  position: sticky; top: 0; z-index: 50;
  background: rgba(14,20,18,0.92);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border);
}
.header-inner {
  max-width: 1100px; margin: 0 auto;
  padding: 0 1.5rem;
  height: 56px;
  display: flex; align-items: center; justify-content: space-between;
}
.logo {
  display: flex; align-items: center; gap: 0.6rem;
  font-family: var(--font-serif);
  font-size: 1.1rem; font-weight: 600;
  letter-spacing: 0.06em;
  color: var(--gold);
  user-select: none;
}
.logo-icon { font-size: 1.25rem; opacity: 0.85; }

.btn-upload-trigger {
  display: flex; align-items: center; gap: 0.4rem;
  padding: 0.4rem 1rem;
  background: transparent;
  border: 1px solid var(--gold-dim);
  border-radius: var(--radius);
  color: var(--gold);
  font-family: var(--font-sans); font-size: 0.82rem;
  cursor: pointer;
  transition: background 0.2s, border-color 0.2s;
}
.btn-upload-trigger:hover {
  background: var(--gold-glow);
  border-color: var(--gold);
}

/* ═══ SHELF ═══ */
.shelf-main {
  max-width: 1100px; margin: 0 auto;
  padding: 2.5rem 1.5rem 4rem;
}
.shelf-header { margin-bottom: 2rem; }
.shelf-title {
  font-family: var(--font-serif);
  font-size: 1.5rem; font-weight: 300;
  letter-spacing: 0.1em;
  color: var(--text);
}
.shelf-sub {
  margin-top: 0.35rem;
  font-size: 0.8rem; color: var(--dim);
  letter-spacing: 0.04em;
}

/* Grid */
.books-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(180px, 1fr));
  gap: 1.25rem;
}

/* Book card */
.book-card {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  cursor: pointer;
  transition: transform 0.18s, border-color 0.18s, box-shadow 0.18s;
  display: flex; flex-direction: column;
}
.book-card:hover {
  transform: translateY(-3px);
  border-color: var(--gold-dim);
  box-shadow: 0 8px 24px rgba(0,0,0,0.4);
}
.book-cover {
  aspect-ratio: 2/3;
  background: linear-gradient(145deg, var(--surface), var(--muted));
  display: flex; flex-direction: column;
  align-items: center; justify-content: center;
  gap: 0.5rem;
  padding: 1rem;
  position: relative;
  overflow: hidden;
}
.book-cover::before {
  content: '';
  position: absolute; inset: 0;
  background: linear-gradient(160deg, transparent 40%, rgba(201,168,76,0.04));
}
.book-cover-icon {
  font-size: 2rem; opacity: 0.3;
}
.book-cover-title {
  font-family: var(--font-serif);
  font-size: 0.75rem; font-weight: 600;
  color: var(--text); text-align: center;
  line-height: 1.4;
  word-break: break-all;
  display: -webkit-box;
  -webkit-line-clamp: 4;
  -webkit-box-orient: vertical;
  overflow: hidden;
}
.book-meta {
  padding: 0.75rem;
  border-top: 1px solid var(--border);
}
.book-meta-title {
  font-size: 0.78rem; font-weight: 400;
  color: var(--text);
  white-space: nowrap; overflow: hidden; text-overflow: ellipsis;
  margin-bottom: 0.2rem;
}
.book-meta-author {
  font-size: 0.7rem; color: var(--dim);
  white-space: nowrap; overflow: hidden; text-overflow: ellipsis;
}

/* Loading */
.loading-state {
  grid-column: 1 / -1;
  display: flex; flex-direction: column; align-items: center; gap: 0.75rem;
  padding: 4rem;
  color: var(--dim); font-size: 0.85rem;
}
.loading-spinner {
  width: 28px; height: 28px;
  border: 2px solid var(--muted);
  border-top-color: var(--gold-dim);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}
@keyframes spin { to { transform: rotate(360deg); } }

.empty-state {
  grid-column: 1 / -1;
  display: flex; flex-direction: column; align-items: center; gap: 0.75rem;
  padding: 5rem 2rem;
  color: var(--dim); font-size: 0.85rem; text-align: center;
}
.empty-state svg { opacity: 0.25; }

/* ═══ UPLOAD MODAL ═══ */
.modal-overlay {
  position: fixed; inset: 0; z-index: 200;
  background: rgba(10,15,13,0.85);
  backdrop-filter: blur(6px);
  display: flex; align-items: center; justify-content: center;
  padding: 1rem;
  opacity: 0; pointer-events: none;
  transition: opacity 0.2s;
}
.modal-overlay.open {
  opacity: 1; pointer-events: auto;
}
.modal-box {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 2rem;
  width: 100%; max-width: 420px;
  position: relative;
  transform: translateY(16px);
  transition: transform 0.2s;
}
.modal-overlay.open .modal-box {
  transform: translateY(0);
}
.modal-close {
  position: absolute; top: 1rem; right: 1rem;
  background: none; border: none; cursor: pointer;
  color: var(--dim); font-size: 1rem;
  transition: color 0.15s;
}
.modal-close:hover { color: var(--text); }
.modal-title {
  font-family: var(--font-serif);
  font-size: 1.1rem; font-weight: 400;
  letter-spacing: 0.08em;
  color: var(--gold);
  margin-bottom: 1.5rem;
}

.form-group { margin-bottom: 1rem; }
.form-group label {
  display: block;
  font-size: 0.75rem; color: var(--dim);
  letter-spacing: 0.04em;
  margin-bottom: 0.4rem;
}
.form-group input[type="text"],
.form-group input[type="password"] {
  width: 100%; padding: 0.55rem 0.75rem;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  color: var(--text);
  font-family: var(--font-sans); font-size: 0.85rem;
  outline: none;
  transition: border-color 0.15s;
}
.form-group input:focus { border-color: var(--gold-dim); }

.file-drop {
  border: 1.5px dashed var(--border);
  border-radius: var(--radius);
  padding: 1.5rem;
  display: flex; flex-direction: column; align-items: center; gap: 0.5rem;
  cursor: pointer;
  color: var(--dim);
  font-size: 0.8rem;
  transition: border-color 0.15s, background 0.15s;
  text-align: center;
}
.file-drop:hover, .file-drop.dragover {
  border-color: var(--gold-dim);
  background: var(--gold-glow);
  color: var(--gold);
}
.file-drop svg { opacity: 0.5; }
.file-drop.has-file { border-color: var(--accent); color: var(--accent); }

.upload-error {
  font-size: 0.78rem; color: #e07070;
  margin-bottom: 0.75rem;
  min-height: 1em;
}

.btn-primary {
  width: 100%; padding: 0.65rem;
  background: var(--gold);
  border: none; border-radius: var(--radius);
  color: var(--ink);
  font-family: var(--font-sans); font-size: 0.875rem; font-weight: 500;
  cursor: pointer;
  transition: background 0.15s, opacity 0.15s;
}
.btn-primary:hover { background: #d4b55c; }
.btn-primary:disabled { opacity: 0.5; cursor: not-allowed; }

.upload-progress { margin-top: 1rem; }
.progress-bar {
  height: 4px; background: var(--border); border-radius: 2px;
  overflow: hidden; margin-bottom: 0.4rem;
}
.progress-fill {
  height: 100%; background: var(--gold);
  width: 0%; transition: width 0.3s;
  border-radius: 2px;
}
#progressLabel { font-size: 0.75rem; color: var(--dim); }

/* ═══ READER ═══ */
.reader-overlay {
  position: fixed; inset: 0; z-index: 300;
  background: var(--ink);
  display: flex; flex-direction: column;
}
.reader-header {
  height: 52px;
  display: flex; align-items: center;
  padding: 0 0.75rem;
  border-bottom: 1px solid var(--border);
  gap: 0.5rem;
  background: var(--surface);
  flex-shrink: 0;
}
.reader-title {
  flex: 1;
  font-family: var(--font-serif);
  font-size: 0.9rem; font-weight: 300;
  letter-spacing: 0.04em;
  color: var(--text-soft);
  text-align: center;
  white-space: nowrap; overflow: hidden; text-overflow: ellipsis;
}
.reader-header-actions {
  display: flex; align-items: center; gap: 0.25rem;
}
.reader-btn {
  background: none; border: none;
  padding: 0.4rem 0.5rem;
  color: var(--dim); font-size: 0.8rem;
  border-radius: var(--radius);
  cursor: pointer;
  transition: color 0.15s, background 0.15s;
  display: flex; align-items: center;
}
.reader-btn:hover { color: var(--text); background: var(--panel); }
.reader-btn.tts-active { color: var(--gold); }

/* TOC panel */
.toc-panel {
  position: absolute; top: 52px; left: 0; bottom: 52px;
  width: 260px;
  background: var(--surface);
  border-right: 1px solid var(--border);
  z-index: 10;
  display: flex; flex-direction: column;
  transform: translateX(-100%);
  transition: transform 0.25s;
  overflow: hidden;
}
.toc-panel.open { transform: translateX(0); }
.toc-header {
  padding: 0.9rem 1rem;
  font-size: 0.75rem; letter-spacing: 0.1em;
  color: var(--dim); text-transform: uppercase;
  border-bottom: 1px solid var(--border);
  flex-shrink: 0;
}
.toc-list {
  overflow-y: auto; flex: 1; padding: 0.5rem 0;
}
.toc-item {
  padding: 0.55rem 1rem;
  font-size: 0.82rem; color: var(--text-soft);
  cursor: pointer; border-left: 2px solid transparent;
  transition: color 0.15s, background 0.15s, border-color 0.15s;
}
.toc-item:hover { color: var(--text); background: var(--panel); }
.toc-item.active { color: var(--gold); border-left-color: var(--gold); }
.toc-item.depth-2 { padding-left: 1.75rem; font-size: 0.78rem; }
.toc-item.depth-3 { padding-left: 2.5rem; font-size: 0.74rem; }

/* Reader body */
.reader-body {
  flex: 1; overflow: hidden;
  position: relative;
}
#epubViewer {
  width: 100%; height: 100%;
}
#epubViewer iframe {
  background: var(--ink) !important;
}

/* Reader nav */
.reader-nav {
  height: 52px;
  display: flex; align-items: center; justify-content: space-between;
  padding: 0 0.5rem;
  border-top: 1px solid var(--border);
  background: var(--surface);
  flex-shrink: 0;
  gap: 0.5rem;
}
.nav-arrow {
  background: none; border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 0.45rem 0.65rem;
  color: var(--dim); cursor: pointer;
  display: flex; align-items: center;
  transition: color 0.15s, border-color 0.15s;
  flex-shrink: 0;
}
.nav-arrow:hover { color: var(--text); border-color: var(--muted); }

.page-indicator {
  font-size: 0.72rem; color: var(--dim);
  flex-shrink: 0;
}

/* TTS controls */
.tts-controls {
  display: flex; align-items: center; gap: 0.75rem;
  flex: 1; justify-content: center;
}
.tts-btn {
  background: none; border: none;
  color: var(--dim); font-size: 1rem;
  cursor: pointer; padding: 0.2rem 0.4rem;
  transition: color 0.15s;
}
.tts-btn:hover { color: var(--gold); }
.tts-speed-group {
  display: flex; align-items: center; gap: 0.4rem;
}
.tts-label { font-size: 0.72rem; color: var(--dim); }
.tts-speed-val { font-size: 0.72rem; color: var(--text-soft); min-width: 2.2rem; }
input[type="range"] {
  -webkit-appearance: none; appearance: none;
  width: 80px; height: 3px;
  background: var(--muted); border-radius: 2px; cursor: pointer;
}
input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none; appearance: none;
  width: 12px; height: 12px;
  background: var(--gold); border-radius: 50%;
}

/* Swipe hint */
.swipe-hint {
  position: absolute; bottom: 70px; left: 50%;
  transform: translateX(-50%);
  background: rgba(0,0,0,0.6);
  color: var(--dim); font-size: 0.72rem;
  padding: 0.3rem 0.75rem;
  border-radius: 20px;
  pointer-events: none;
  opacity: 0;
  transition: opacity 0.3s;
}

/* ═══ RESPONSIVE ═══ */
@media (max-width: 600px) {
  .books-grid {
    grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
    gap: 0.9rem;
  }
  .toc-panel { width: 80vw; }
  .tts-label { display: none; }
  input[type="range"] { width: 60px; }
}

/* Scrollbar */
::-webkit-scrollbar { width: 5px; height: 5px; }
::-webkit-scrollbar-track { background: var(--surface); }
::-webkit-scrollbar-thumb { background: var(--muted); border-radius: 3px; }
::-webkit-scrollbar-thumb:hover { background: var(--dim); }