:root {
  --bg: #0f1115;
  --panel: #171a21;
  --panel-2: #1e222b;
  --text: #e8eaf0;
  --muted: #9aa3b2;
  --accent: #5b8cff;
  --accent-strong: #3f6ef0;
  --danger: #ff6b6b;
  --radius: 14px;
  --shadow: 0 10px 40px rgba(0, 0, 0, 0.45);
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  background: var(--bg);
  color: var(--text);
  font-family: ui-sans-serif, system-ui, -apple-system, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  min-height: 100vh;
}

main {
  max-width: 1100px;
  margin: 0 auto;
  padding: 24px 20px 80px;
}

.hidden { display: none !important; }

/* Topbar */
.topbar {
  text-align: center;
  padding: 40px 20px 8px;
}
.logo {
  font-size: 2.2rem;
  margin: 0;
  letter-spacing: -0.02em;
}
.logo span { color: var(--accent); }
.tagline {
  color: var(--muted);
  margin: 8px 0 0;
  font-size: 0.95rem;
}

/* Dropzone */
.dropzone {
  margin-top: 28px;
  border: 2px dashed #3a4152;
  border-radius: var(--radius);
  background: var(--panel);
  padding: 56px 24px;
  text-align: center;
  cursor: pointer;
  transition: border-color 0.15s ease, background 0.15s ease, transform 0.1s ease;
  outline: none;
}
.dropzone:hover, .dropzone:focus-visible { border-color: var(--accent); }
.dropzone.dragover {
  border-color: var(--accent);
  background: var(--panel-2);
  transform: scale(1.005);
}
.dz-inner svg { color: var(--accent); }
.dz-title { font-size: 1.1rem; margin: 14px 0 4px; }
.dz-sub { color: var(--muted); margin: 0; font-size: 0.9rem; }
.link-btn {
  background: none;
  border: none;
  color: var(--accent);
  cursor: pointer;
  font: inherit;
  text-decoration: underline;
  padding: 0;
}

/* Progress */
.progress-wrap { margin-top: 28px; }
.progress-bar {
  height: 8px;
  background: var(--panel-2);
  border-radius: 999px;
  overflow: hidden;
}
.progress-fill {
  height: 100%;
  width: 0%;
  background: linear-gradient(90deg, var(--accent), var(--accent-strong));
  transition: width 0.2s ease;
}
.progress-label {
  color: var(--muted);
  font-size: 0.85rem;
  margin: 10px 2px 0;
}

/* Preview */
.preview-wrap { margin-top: 28px; }
.preview-toolbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 12px;
  flex-wrap: wrap;
  margin-bottom: 16px;
}
.page-nav { display: flex; align-items: center; gap: 12px; }
.page-indicator { color: var(--muted); font-size: 0.9rem; min-width: 64px; text-align: center; }
.actions { display: flex; gap: 10px; }

.stage {
  background: var(--panel);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 24px;
  display: flex;
  justify-content: center;
  overflow: auto;
}
.flipbook { margin: 0 auto; }

/* Buttons */
.btn {
  border: 1px solid transparent;
  border-radius: 10px;
  padding: 9px 16px;
  font-size: 0.9rem;
  cursor: pointer;
  transition: background 0.15s ease, border-color 0.15s ease, opacity 0.15s ease;
  font-weight: 600;
}
.btn:disabled { opacity: 0.5; cursor: not-allowed; }
.btn.primary { background: var(--accent); color: #0b0e14; }
.btn.primary:hover:not(:disabled) { background: var(--accent-strong); color: #fff; }
.btn.ghost { background: transparent; color: var(--text); border-color: #3a4152; }
.btn.ghost:hover:not(:disabled) { border-color: var(--accent); }

/* Toast */
.toast {
  position: fixed;
  left: 50%;
  bottom: 32px;
  transform: translateX(-50%) translateY(20px);
  background: var(--panel-2);
  color: var(--text);
  border: 1px solid #3a4152;
  padding: 12px 20px;
  border-radius: 12px;
  box-shadow: var(--shadow);
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.2s ease, transform 0.2s ease;
  max-width: min(90vw, 560px);
  overflow-wrap: anywhere;
  z-index: 50;
}
.toast.show { opacity: 1; transform: translateX(-50%) translateY(0); }
.toast.error { border-color: var(--danger); color: #ffd5d5; }

/* Viewer */
.viewer-body { overflow: hidden; }
.viewer-main {
  max-width: none;
  padding: 0;
  height: 100vh;
  display: flex;
  flex-direction: column;
}
.viewer-loading {
  flex: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--muted);
  font-size: 1rem;
}
.viewer-stage {
  flex: 1;
  border-radius: 0;
  box-shadow: none;
  align-items: center;
  padding: 16px;
  min-height: 0;
}
.viewer-nav {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 14px;
  padding: 12px;
  background: var(--panel);
}

@media (max-width: 640px) {
  .preview-toolbar { justify-content: center; }
}

/* Mode toggle */
.mode-toggle { display: flex; gap: 0; border: 1px solid #3a4152; border-radius: 10px; overflow: hidden; }
.mode-btn { border: none; border-radius: 0; padding: 9px 14px; background: transparent; color: var(--muted); }
.mode-btn + .mode-btn { border-left: 1px solid #3a4152; }
.mode-btn.active { background: var(--accent); color: #0b0e14; }
.mode-btn:not(.active):hover { color: var(--text); }

/* Share modal */
.modal-backdrop {
  position: fixed; inset: 0; background: rgba(8, 10, 14, 0.72);
  display: flex; align-items: center; justify-content: center; z-index: 100; padding: 20px;
}
.modal {
  background: var(--panel-2); border: 1px solid #3a4152; border-radius: var(--radius);
  box-shadow: var(--shadow); padding: 28px; width: min(92vw, 480px); text-align: center;
}
.modal h2 { margin: 0 0 6px; font-size: 1.3rem; }
.modal-sub { color: var(--muted); margin: 0 0 16px; font-size: 0.9rem; }
.share-row { display: flex; gap: 8px; margin-bottom: 12px; }
.share-link {
  flex: 1; background: var(--bg); border: 1px solid #3a4152; border-radius: 10px;
  color: var(--text); padding: 10px 12px; font-size: 0.85rem; min-width: 0;
}
.share-link:focus { outline: none; border-color: var(--accent); }
.copy-feedback { color: #7ee2a0; font-size: 0.85rem; margin: 0 0 12px; }
.modal-close { width: 100%; }

/* Compression panel */
.compression-panel { background: var(--panel); border: 1px solid #3a4152; border-radius: var(--radius); padding: 16px 18px; margin-bottom: 16px; }
.comp-row { display: flex; align-items: center; gap: 14px; margin-bottom: 12px; flex-wrap: wrap; }
.comp-row:last-child { margin-bottom: 0; }
.comp-label { color: var(--muted); font-size: 0.85rem; font-weight: 600; min-width: 90px; }
.comp-mode { display: flex; border: 1px solid #3a4152; border-radius: 10px; overflow: hidden; }
.comp-slider-row input[type="range"] { flex: 1; min-width: 160px; }
.quality-value { font-variant-numeric: tabular-nums; color: var(--text); min-width: 44px; text-align: right; font-size: 0.9rem; }
.comp-meta { justify-content: space-between; }
.size-estimate { color: var(--muted); font-size: 0.85rem; }
.size-warning { color: #ffb454; background: rgba(255, 180, 84, 0.08); border: 1px solid rgba(255, 180, 84, 0.35); border-radius: 10px; padding: 10px 12px; font-size: 0.85rem; margin: 12px 0 0; }
input[type="range"] { accent-color: var(--accent); height: 4px; cursor: pointer; }

/* Edit-mode banner */
.edit-banner { display: flex; align-items: center; justify-content: center; gap: 14px; background: rgba(91,140,255,0.1); border: 1px solid rgba(91,140,255,0.35); border-radius: 10px; padding: 10px 16px; margin: 14px auto 0; max-width: 1100px; flex-wrap: wrap; }
.edit-banner code { background: var(--bg); padding: 2px 8px; border-radius: 6px; color: var(--accent); font-weight: 600; }
.edit-banner .btn.sm { padding: 5px 12px; font-size: 0.8rem; }

/* Page nav below the flipbook */
.preview-page-nav { justify-content: center; margin-top: 16px; gap: 16px; }