:root {
  --bg: #f4f6fb;
  --card: #ffffff;
  --border: #e6e9f2;
  --text: #23283b;
  --muted: #7a819e;
  --accent: #4f6ef7;
  --accent-dark: #3b57d9;
  --warn-bg: #fff8e6;
  --warn-border: #ffe1a3;
  --warn-text: #8a6116;
  --radius: 12px;
  --shadow: 0 4px 18px rgba(35, 40, 59, 0.06);
}

* { box-sizing: border-box; margin: 0; padding: 0; }

body {
  font-family: "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

.container { width: min(1180px, 92%); margin: 0 auto; }

.site-header {
  background: linear-gradient(120deg, #4f6ef7 0%, #7a5af8 100%);
  color: #fff;
  padding: 34px 0 46px;
}
.site-header h1 { font-size: 26px; font-weight: 700; display: flex; align-items: center; gap: 10px; }
.subtitle { margin-top: 6px; opacity: 0.88; font-size: 14px; }

.layout {
  display: grid;
  grid-template-columns: 460px 1fr;
  gap: 24px;
  margin-top: -26px;
  flex: 1;
  padding-bottom: 40px;
}
@media (max-width: 900px) { .layout { grid-template-columns: 1fr; } }

.panel {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 24px 26px;
  align-self: start;
}
.panel-title { font-size: 16px; font-weight: 600; margin: 20px 0 14px; }
.panel-title:first-child { margin-top: 0; }

/* 上传区 */
.dropzone {
  border: 2px dashed #c9d2f5;
  border-radius: var(--radius);
  background: #fafbff;
  cursor: pointer;
  transition: border-color .2s, background .2s;
  outline: none;
}
.dropzone:hover, .dropzone.dragover { border-color: var(--accent); background: #f2f5ff; }
.dz-inner { padding: 34px 16px; text-align: center; }
.dz-icon { font-size: 28px; color: var(--accent); }
.dz-text { margin-top: 8px; font-size: 14px; }
.dz-hint { margin-top: 4px; font-size: 12px; color: var(--muted); }

.file-info {
  margin-top: 12px;
  padding: 10px 14px;
  background: #eef2ff;
  border: 1px solid #d8e0ff;
  border-radius: 8px;
  font-size: 13px;
  display: flex;
  justify-content: space-between;
}

/* 表单 */
.form-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px 16px;
}
.field { display: flex; flex-direction: column; gap: 6px; font-size: 13px; color: var(--muted); }
.field b { color: var(--accent); font-weight: 600; }
.field input[type="text"], .field select {
  padding: 9px 12px;
  border: 1px solid var(--border);
  border-radius: 8px;
  font-size: 14px;
  color: var(--text);
  background: #fff;
  transition: border-color .2s;
}
.field input[type="text"]:focus, .field select:focus { outline: none; border-color: var(--accent); }
.field input[type="range"] { accent-color: var(--accent); }

.checks {
  margin-top: 14px;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 8px;
  font-size: 13px;
}
.checks label { display: flex; align-items: center; gap: 7px; cursor: pointer; }
.checks input { accent-color: var(--accent); }

/* 按钮 */
.actions { margin-top: 22px; display: flex; gap: 12px; }
.btn {
  flex: 1;
  padding: 12px 18px;
  border: none;
  border-radius: 9px;
  font-size: 14px;
  font-weight: 600;
  cursor: pointer;
  transition: background .2s, transform .1s;
}
.btn:active:not(:disabled) { transform: translateY(1px); }
.btn:disabled { opacity: 0.45; cursor: not-allowed; }
.btn-primary { background: var(--accent); color: #fff; }
.btn-primary:hover:not(:disabled) { background: var(--accent-dark); }
.btn-secondary { background: #eceffd; color: var(--accent); }
.btn-secondary:hover:not(:disabled) { background: #dfe6fd; }

.status { margin-top: 12px; font-size: 13px; color: var(--muted); min-height: 18px; }
.status.error { color: #d64545; }

/* 结果区 */
.empty-result { padding: 40px 10px; text-align: center; color: var(--muted); font-size: 14px; }
.book-meta { font-size: 15px; margin-bottom: 12px; }
.book-meta .book-title { font-weight: 700; font-size: 17px; }
.book-meta .book-author { color: var(--muted); margin-left: 8px; font-size: 13px; }

.stats { display: flex; flex-wrap: wrap; gap: 8px; margin-bottom: 14px; }
.chip {
  background: #eef2ff;
  color: #4052c8;
  border-radius: 999px;
  padding: 5px 12px;
  font-size: 12.5px;
  font-weight: 600;
}

.warnings { margin-bottom: 14px; }
.warn-item {
  background: var(--warn-bg);
  border: 1px solid var(--warn-border);
  color: var(--warn-text);
  border-radius: 8px;
  padding: 9px 13px;
  font-size: 13px;
  margin-bottom: 8px;
}
.ok-item {
  background: #eafaf0;
  border: 1px solid #bce8cd;
  color: #217a45;
  border-radius: 8px;
  padding: 9px 13px;
  font-size: 13px;
}

.toc-heading { font-size: 14px; font-weight: 600; margin: 6px 0 10px; color: var(--muted); }

.chapter-tree {
  max-height: 460px;
  overflow-y: auto;
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 6px;
}
.ch-item {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 7px 10px;
  font-size: 13.5px;
  border-radius: 6px;
}
.ch-item:hover { background: #f4f6ff; }
.ch-item .ch-title { overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.ch-item .ch-meta { color: var(--muted); font-size: 12px; flex-shrink: 0; margin-left: 10px; }
.ch-item.lv1 .ch-title { font-weight: 700; }
.ch-item.lv2 { padding-left: 26px; }
.ch-item.lv3 { padding-left: 44px; }
.ch-item.lv4 { padding-left: 62px; }

.site-footer { padding: 18px 0 26px; text-align: center; color: var(--muted); font-size: 12px; }

.hidden { display: none !important; }

/* 预览按钮 */
.btn-ghost {
  background: transparent;
  color: var(--accent);
  border: 1px solid #c9d2f5;
}
.btn-ghost:hover:not(:disabled) { background: #eef2ff; }

/* 预览弹窗 */
.modal {
  position: fixed;
  inset: 0;
  background: rgba(20, 24, 40, 0.55);
  z-index: 100;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 20px;
}
.modal-box {
  background: var(--card);
  border-radius: var(--radius);
  box-shadow: 0 18px 60px rgba(0, 0, 0, 0.28);
  width: min(1180px, 100%);
  height: min(860px, 100%);
  display: flex;
  flex-direction: column;
  overflow: hidden;
}
.modal-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: 10px 16px;
  border-bottom: 1px solid var(--border);
  background: #fafbff;
}
.modal-title {
  font-size: 14px;
  font-weight: 600;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}
.modal-tools { display: flex; align-items: center; gap: 8px; flex-shrink: 0; }
.tool-btn {
  padding: 6px 12px;
  border: 1px solid var(--border);
  border-radius: 7px;
  background: #fff;
  color: var(--text);
  font-size: 13px;
  cursor: pointer;
  transition: background .15s;
}
.tool-btn:hover:not(:disabled) { background: #eef2ff; }
.tool-btn:disabled { opacity: 0.4; cursor: not-allowed; }
.close-btn { color: #d64545; }
.close-btn:hover { background: #fdecec; }
.pv-page { font-size: 13px; color: var(--muted); min-width: 64px; text-align: center; }

.modal-body { flex: 1; display: flex; min-height: 0; }
.preview-toc {
  width: 240px;
  flex-shrink: 0;
  border-right: 1px solid var(--border);
  overflow-y: auto;
  padding: 10px 8px;
  background: #fafbff;
}
.toc-caption { font-size: 12px; font-weight: 600; color: var(--muted); padding: 2px 8px 8px; }
.toc-empty { font-size: 12.5px; color: var(--muted); padding: 8px; }
.toc-item {
  display: block;
  width: 100%;
  text-align: left;
  border: none;
  background: none;
  padding: 7px 10px;
  font-size: 13px;
  color: var(--text);
  border-radius: 6px;
  cursor: pointer;
  line-height: 1.4;
}
.toc-item:hover { background: #eef2ff; color: var(--accent-dark); }
.toc-item.lv1 { font-weight: 600; }
.toc-item.lv2 { padding-left: 24px; }
.toc-item.lv3 { padding-left: 40px; }
.toc-item.lv4 { padding-left: 56px; }

.preview-content {
  flex: 1;
  overflow-y: auto;
  background: #e8eaf2;
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: 18px;
  min-width: 0;
}
.preview-content canvas {
  background: #fff;
  box-shadow: 0 4px 16px rgba(35, 40, 59, 0.18);
  max-width: 100%;
  height: auto !important;
}
.preview-content.epub-mode { padding: 0; background: #fff; }
@media (max-width: 700px) {
  .preview-toc { display: none; }
}
.spinner::after {
  content: "";
  display: inline-block;
  width: 12px; height: 12px;
  margin-left: 8px;
  border: 2px solid rgba(255,255,255,.4);
  border-top-color: #fff;
  border-radius: 50%;
  animation: spin .8s linear infinite;
  vertical-align: -2px;
}
.btn-secondary.spinner::after { border-color: rgba(79,110,247,.3); border-top-color: var(--accent); }
@keyframes spin { to { transform: rotate(360deg); } }