:root {
  --bg: #f4f5f7;
  --surface: #ffffff;
  --border: #e2e4e9;
  --text: #1c1e21;
  --text-muted: #6b7280;
  --primary: #4338ca;
  --primary-hover: #372ea8;
  --accent: #0f9d58;
  --accent-hover: #0c7d46;
  --danger: #e53935;
  --shadow: 0 1px 3px rgba(16, 24, 40, 0.08), 0 1px 2px rgba(16, 24, 40, 0.06);
  --shadow-lg: 0 10px 30px rgba(16, 24, 40, 0.18);
  --radius: 10px;
}

* { box-sizing: border-box; }

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

button { font-family: inherit; }

.hidden { display: none !important; }
.muted { color: var(--text-muted); margin: 0; }
.muted.small { font-size: 0.85rem; }

/* Topbar */
.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 12px 24px;
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 20;
}

.brand {
  display: flex;
  align-items: center;
  gap: 8px;
  font-weight: 700;
  font-size: 1.2rem;
}
.brand-icon { font-size: 1.4rem; }

.topbar-actions {
  display: flex;
  gap: 10px;
  align-items: center;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 9px 16px;
  border-radius: 8px;
  border: 1px solid var(--border);
  background: var(--surface);
  color: var(--text);
  font-size: 0.92rem;
  font-weight: 600;
  cursor: pointer;
  transition: background 0.15s, border-color 0.15s, transform 0.05s, box-shadow 0.15s;
  white-space: nowrap;
}
.btn:hover { background: #f0f1f4; }
.btn:active { transform: translateY(1px); }
.btn:disabled { opacity: 0.45; cursor: not-allowed; }

.btn-primary {
  background: var(--primary);
  border-color: var(--primary);
  color: #fff;
}
.btn-primary:hover { background: var(--primary-hover); }

.btn-accent {
  background: var(--accent);
  border-color: var(--accent);
  color: #fff;
}
.btn-accent:hover:not(:disabled) { background: var(--accent-hover); }

.btn-ghost { background: transparent; }

/* Main / dropzone */
#main-view { padding: 24px; max-width: 1200px; margin: 0 auto; }

.dropzone {
  border: 2px dashed #c7c9d1;
  border-radius: var(--radius);
  background: var(--surface);
  min-height: 60vh;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  transition: border-color 0.15s, background 0.15s;
}
.dropzone.drag-over {
  border-color: var(--primary);
  background: #f1efff;
}
.dropzone-inner { max-width: 480px; padding: 24px; }
.dropzone-icon { font-size: 3rem; margin-bottom: 8px; }
.dropzone-inner h1 { font-size: 1.4rem; margin: 0 0 6px; }
.dropzone-hint { font-size: 0.9rem; color: var(--text-muted); }

/* Grid view */
.grid-toolbar {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  margin-bottom: 14px;
  flex-wrap: wrap;
  gap: 6px;
}

.page-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(160px, 1fr));
  gap: 18px;
}

.page-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  overflow: hidden;
  cursor: grab;
  position: relative;
  transition: transform 0.12s, box-shadow 0.12s;
  user-select: none;
}
.page-card:active { cursor: grabbing; }
.page-card.dragging { opacity: 0.35; }
.page-card.drag-over-target { outline: 3px solid var(--primary); outline-offset: -3px; }
.page-card:hover { box-shadow: var(--shadow-lg); transform: translateY(-2px); }

.page-thumb-wrap {
  position: relative;
  background: #e9eaee;
  display: flex;
  align-items: center;
  justify-content: center;
}
.page-thumb-wrap canvas { width: 100%; display: block; }

.page-number {
  position: absolute;
  top: 6px;
  left: 6px;
  background: rgba(0,0,0,0.65);
  color: #fff;
  font-size: 0.72rem;
  font-weight: 700;
  padding: 2px 7px;
  border-radius: 20px;
}

.page-annot-dot {
  position: absolute;
  top: 6px;
  right: 6px;
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: var(--accent);
  border: 2px solid #fff;
}

.page-actions {
  position: absolute;
  inset: 0;
  background: rgba(20,20,24,0.55);
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  opacity: 0;
  transition: opacity 0.12s;
}
.page-card:hover .page-actions { opacity: 1; }

.icon-btn {
  width: 34px;
  height: 34px;
  border-radius: 50%;
  border: none;
  background: #fff;
  font-size: 1rem;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: var(--shadow);
}
.icon-btn:hover { background: #eee; }
.icon-btn.danger:hover { background: #fdecea; color: var(--danger); }

.page-source {
  padding: 6px 10px;
  font-size: 0.72rem;
  color: var(--text-muted);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  border-top: 1px solid var(--border);
}

/* Editor */
.editor {
  position: fixed;
  inset: 0;
  background: #24262b;
  z-index: 100;
  display: flex;
  flex-direction: column;
}

.editor-toolbar {
  display: flex;
  align-items: center;
  gap: 18px;
  flex-wrap: wrap;
  padding: 10px 18px;
  background: #1a1b1e;
  border-bottom: 1px solid #33353a;
}
.editor-toolbar .btn { background: #2d2f34; color: #eee; border-color: #3d3f45; }
.editor-toolbar .btn:hover { background: #3a3c42; }
.editor-toolbar .muted { color: #a9adb4; }

.tool-group {
  display: flex;
  align-items: center;
  gap: 6px;
  padding-right: 14px;
  border-right: 1px solid #33353a;
}
.tool-group:last-child { border-right: none; }

.tool-btn {
  padding: 8px 12px;
  border-radius: 8px;
  border: 1px solid #3d3f45;
  background: #2d2f34;
  color: #ddd;
  font-size: 0.85rem;
  font-weight: 600;
  cursor: pointer;
}
.tool-btn:hover { background: #3a3c42; }
.tool-btn.active {
  background: var(--primary);
  border-color: var(--primary);
  color: #fff;
}

.swatch {
  width: 24px;
  height: 24px;
  border-radius: 50%;
  border: 2px solid transparent;
  cursor: pointer;
  display: inline-block;
}
.swatch.active { border-color: #fff; box-shadow: 0 0 0 2px var(--primary); }

#custom-color {
  width: 28px;
  height: 28px;
  border: none;
  background: none;
  cursor: pointer;
  border-radius: 6px;
  overflow: hidden;
  padding: 0;
}

.range-label {
  color: #ddd;
  font-size: 0.82rem;
  display: flex;
  align-items: center;
  gap: 6px;
}

.highlight-hint {
  margin: 0;
  padding: 8px 18px;
  background: #383018;
  color: #ffe082;
  font-size: 0.82rem;
  line-height: 1.4;
  min-height: calc(0.82rem * 1.4 * 2 + 16px);
  display: flex;
  align-items: center;
  border-bottom: 1px solid #4a3f1e;
}

.canvas-wrap {
  flex: 1;
  overflow: auto;
  display: flex;
  align-items: flex-start;
  justify-content: center;
  padding: 30px;
}

.canvas-stage {
  position: relative;
  background: #fff;
  box-shadow: var(--shadow-lg);
  line-height: 0;
}

.canvas-stage canvas { display: block; }

#annotation-canvas {
  position: absolute;
  top: 0;
  left: 0;
}

/* Text tool inline editor */
.text-input-overlay {
  position: absolute;
  min-width: 40px;
  background: transparent;
  border: 1px dashed #4338ca;
  outline: none;
  font-family: Helvetica, Arial, sans-serif;
  padding: 2px 4px;
  resize: none;
  overflow: hidden;
  white-space: pre;
}

input[type="range"]:disabled { opacity: 0.35; cursor: not-allowed; }

/* Signature modal */
.modal-backdrop {
  position: fixed;
  inset: 0;
  background: rgba(10, 10, 14, 0.6);
  z-index: 300;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 20px;
}

.modal-panel {
  background: var(--surface);
  color: var(--text);
  border-radius: 14px;
  width: 100%;
  max-width: 640px;
  max-height: 88vh;
  overflow-y: auto;
  box-shadow: var(--shadow-lg);
  padding: 20px 24px 24px;
}

.modal-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 12px;
}
.modal-header h2 { margin: 0; font-size: 1.2rem; }

.modal-tabs {
  display: flex;
  gap: 6px;
  border-bottom: 1px solid var(--border);
  margin-bottom: 16px;
  flex-wrap: wrap;
}
.modal-tab {
  padding: 8px 14px;
  border: none;
  background: transparent;
  font-weight: 600;
  font-size: 0.88rem;
  color: var(--text-muted);
  cursor: pointer;
  border-bottom: 2px solid transparent;
}
.modal-tab:hover { color: var(--text); }
.modal-tab.active { color: var(--primary); border-bottom-color: var(--primary); }

.modal-view.hidden { display: none; }

.modal-actions {
  display: flex;
  justify-content: flex-end;
  gap: 10px;
  margin-top: 14px;
}

.sig-gallery {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(160px, 1fr));
  gap: 14px;
  margin-bottom: 10px;
}

.sig-card {
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 10px;
  background: #fafafa;
  display: flex;
  flex-direction: column;
  gap: 6px;
}
.sig-card img {
  width: 100%;
  height: 70px;
  object-fit: contain;
  background: #fff;
  border-radius: 6px;
  border: 1px solid var(--border);
}
.sig-card-label {
  font-size: 0.8rem;
  color: var(--text-muted);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}
.sig-card-actions {
  display: flex;
  gap: 6px;
  align-items: center;
}
.sig-card-actions .btn { flex: 1; padding: 6px 10px; font-size: 0.82rem; }

.sig-pad {
  width: 100%;
  max-width: 560px;
  height: auto;
  aspect-ratio: 560 / 200;
  background: #fff;
  border: 2px dashed #c7c9d1;
  border-radius: 10px;
  cursor: crosshair;
  touch-action: none;
  display: block;
}

.sig-auto-form { display: flex; flex-direction: column; gap: 12px; }
.sig-auto-form label {
  display: flex;
  flex-direction: column;
  gap: 4px;
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-muted);
}
.sig-auto-form input[type="text"] {
  padding: 9px 12px;
  border-radius: 8px;
  border: 1px solid var(--border);
  font-size: 0.95rem;
  font-family: inherit;
}

.sig-style-picker {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
}
.sig-style-btn {
  padding: 10px 16px;
  border-radius: 8px;
  border: 1px solid var(--border);
  background: #fff;
  font-size: 1.1rem;
  cursor: pointer;
}
.sig-style-btn.active { border-color: var(--primary); box-shadow: 0 0 0 2px rgba(67,56,197,0.25); }

.sig-auto-preview-wrap {
  border: 2px dashed #c7c9d1;
  border-radius: 10px;
  background: #fff;
  overflow: hidden;
}
.sig-auto-preview {
  width: 100%;
  height: auto;
  aspect-ratio: 640 / 140;
  display: block;
}

/* Toast */
.toast {
  position: fixed;
  bottom: 24px;
  left: 50%;
  transform: translateX(-50%);
  background: #212121;
  color: #fff;
  padding: 10px 20px;
  border-radius: 8px;
  font-size: 0.88rem;
  box-shadow: var(--shadow-lg);
  z-index: 200;
}

@media (max-width: 700px) {
  .topbar { padding: 10px 14px; }
  .brand-name { display: none; }
  #main-view { padding: 14px; }
  .editor-toolbar { gap: 10px; }
}