:root {
  --bg: #eef1f5;
  --panel: #ffffff;
  --border: #e2e6ec;
  --text: #1f2937;
  --muted: #6b7280;
  --accent: #2563eb;
  --accent-hover: #1d4ed8;
  --danger: #dc2626;
  --shadow: 0 1px 3px rgba(15, 23, 42, 0.08);
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  height: 100%;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  color: var(--text);
  background: var(--bg);
}

body { display: flex; flex-direction: column; overflow: hidden; }

/* ---------- 顶部工具栏 ---------- */
#topbar {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 10px 16px;
  background: var(--panel);
  border-bottom: 1px solid var(--border);
  box-shadow: var(--shadow);
  flex-wrap: wrap;
  z-index: 5;
}

.brand {
  display: flex;
  align-items: center;
  gap: 8px;
  font-weight: 600;
  font-size: 15px;
  color: var(--accent);
  margin-right: 4px;
  white-space: nowrap;
}

.toolbar { display: flex; align-items: center; gap: 10px; flex-wrap: wrap; }

.sep { width: 1px; height: 26px; background: var(--border); }

.group {
  display: flex;
  align-items: center;
  background: #f3f5f8;
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 3px;
  gap: 2px;
}

.tool-btn {
  border: none;
  background: transparent;
  padding: 7px 12px;
  border-radius: 6px;
  cursor: pointer;
  font-size: 13px;
  color: var(--muted);
  white-space: nowrap;
  transition: all 0.15s;
}
.tool-btn:hover { color: var(--text); background: rgba(0, 0, 0, 0.04); }
.tool-btn.active { background: #fff; color: var(--accent); box-shadow: 0 1px 2px rgba(0, 0, 0, 0.1); font-weight: 600; }

.btn {
  border: 1px solid var(--border);
  background: #fff;
  padding: 7px 13px;
  border-radius: 8px;
  cursor: pointer;
  font-size: 13px;
  color: var(--text);
  transition: all 0.15s;
  white-space: nowrap;
}
.btn:hover { border-color: #c7cdd6; background: #f9fafb; }
.btn:disabled { opacity: 0.45; cursor: not-allowed; }

.btn-primary {
  background: var(--accent);
  border-color: var(--accent);
  color: #fff;
  font-weight: 600;
}
.btn-primary:hover { background: var(--accent-hover); border-color: var(--accent-hover); }
.btn-primary:disabled { background: #93b4f0; border-color: #93b4f0; color: #fff; }

.icon-btn { padding: 7px 11px; }

.btn-large { padding: 11px 24px; font-size: 15px; }

.color-picker {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 13px;
  color: var(--muted);
  cursor: pointer;
  padding: 4px 8px;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: #fff;
}
.color-picker input[type="color"] {
  width: 24px;
  height: 24px;
  border: none;
  padding: 0;
  background: none;
  cursor: pointer;
  border-radius: 4px;
}
.color-picker.disabled { opacity: 0.45; pointer-events: none; }

.size-control {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 13px;
  color: var(--muted);
  padding: 4px 10px;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: #fff;
}
.size-control input[type="range"] { width: 110px; accent-color: var(--accent); }
.size-val { min-width: 22px; text-align: center; color: var(--text); font-weight: 600; font-variant-numeric: tabular-nums; }

/* ---------- 状态栏 ---------- */
#statusbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 6px 16px;
  background: #f8fafc;
  border-bottom: 1px solid var(--border);
  font-size: 13px;
  color: var(--muted);
}
#statusbar .left, #statusbar .right { display: flex; align-items: center; gap: 10px; }
.nav-btn {
  border: 1px solid var(--border);
  background: #fff;
  border-radius: 6px;
  cursor: pointer;
  font-size: 15px;
  line-height: 1;
  padding: 5px 11px;
  color: var(--text);
}
.nav-btn:hover { border-color: #c7cdd6; background: #f9fafb; }
.nav-btn:disabled { opacity: 0.4; cursor: not-allowed; }
#pageInfo, #zoomInfo { min-width: 60px; text-align: center; font-variant-numeric: tabular-nums; }

/* ---------- 主区域 ---------- */
#main { flex: 1; overflow: hidden; display: flex; }

#editorArea { flex: 1; position: relative; min-width: 0; }

/* ---------- 左侧缩略图栏 ---------- */
#sidebar {
  width: 152px;
  flex: none;
  background: #f8fafc;
  border-right: 1px solid var(--border);
  overflow-y: auto;
  overflow-x: hidden;
}
.sidebar-head {
  padding: 10px 12px;
  font-size: 13px;
  font-weight: 600;
  color: var(--text);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  background: #f8fafc;
  z-index: 1;
}
.sidebar-head span { color: var(--muted); font-weight: 400; }

.thumb {
  position: relative;
  padding: 10px 12px 8px;
  cursor: pointer;
  border-bottom: 1px solid #edf0f4;
  transition: background 0.12s;
}
.thumb:hover { background: #eef2f8; }
.thumb.active { background: #e3ecff; }
.thumb .num {
  font-size: 11px;
  color: var(--muted);
  margin-bottom: 5px;
  user-select: none;
}
.thumb canvas {
  display: block;
  width: 100%;
  height: auto;
  background: #fff;
  border: 1px solid var(--border);
  border-radius: 2px;
  box-shadow: 0 1px 2px rgba(15, 23, 42, 0.06);
}
.thumb.active canvas { border-color: var(--accent); box-shadow: 0 0 0 2px rgba(37, 99, 235, 0.35); }
.thumb .badge {
  position: absolute;
  top: 8px;
  right: 8px;
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--accent);
  border: 2px solid #fff;
  box-shadow: 0 0 0 1px var(--accent);
}
.thumb .badge.hidden { display: none; }

.drop-zone {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  background:
    radial-gradient(circle at 20% 20%, #ffffff 0%, #eef1f5 70%);
}
.drop-zone.dragover { background: #e3ecff; outline: 3px dashed var(--accent); outline-offset: -16px; }
.drop-inner { text-align: center; max-width: 520px; padding: 24px; }
.drop-icon { font-size: 64px; }
.drop-inner h1 { font-size: 26px; margin: 12px 0 8px; font-weight: 700; }
.drop-inner p { color: var(--muted); font-size: 14px; margin: 0 0 20px; line-height: 1.6; }
.drop-inner .hint { font-size: 12px; color: #9aa3af; margin-top: 16px; }

.app-area {
  position: absolute;
  inset: 0;
  overflow: auto;
  padding: 0;
}
.hidden { display: none !important; }

#stage {
  width: max-content;
  height: max-content;
}

.canvas-wrap {
  position: relative;
  width: fit-content;
  background: #fff;
  box-shadow: 0 2px 12px rgba(15, 23, 42, 0.16);
  border-radius: 2px;
}
.canvas-wrap canvas {
  display: block;
  position: absolute;
  top: 0;
  left: 0;
  border-radius: 2px;
}
#pdfCanvas { position: relative; }
#overlayCanvas { position: absolute; top: 0; left: 0; cursor: none; touch-action: none; }
.canvas-wrap.tool-rect #overlayCanvas { cursor: crosshair; }

.brush-cursor {
  position: absolute;
  pointer-events: none;
  border: 1.5px solid var(--accent);
  border-radius: 50%;
  transform: translate(-50%, -50%);
  z-index: 3;
  background: rgba(37, 99, 235, 0.08);
}

/* ---------- 加载遮罩 ---------- */
.loading {
  position: fixed;
  inset: 0;
  background: rgba(255, 255, 255, 0.82);
  backdrop-filter: blur(2px);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 16px;
  z-index: 100;
  font-size: 14px;
  color: var(--text);
}
.spinner {
  width: 40px;
  height: 40px;
  border: 4px solid #dbe2ec;
  border-top-color: var(--accent);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}
@keyframes spin { to { transform: rotate(360deg); } }

/* 移动端适配 */
@media (max-width: 720px) {
  #topbar { padding: 8px; gap: 8px; }
  .toolbar { gap: 6px; }
  .size-control input[type="range"] { width: 72px; }
  .brand span { display: none; }
}