:root {
  --bg: #0d1117;
  --bg-panel: rgba(22, 27, 34, 0.85);
  --bg-elev: rgba(33, 40, 50, 0.92);
  --fg: #e6edf3;
  --fg-dim: #9aa7b4;
  --accent: #58a6ff;
  --border: rgba(255, 255, 255, 0.08);
  --purple: #a371f7;
  --shadow: 0 8px 32px rgba(0, 0, 0, 0.45);
}

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

html, body {
  width: 100%;
  height: 100%;
  overflow: hidden;
  background: radial-gradient(ellipse at 50% 40%, #131a26 0%, var(--bg) 70%);
  color: var(--fg);
  font-family: "Microsoft YaHei", "PingFang SC", "Noto Sans SC", sans-serif;
}

.hidden { display: none !important; }

/* ---------------- 顶部栏 ---------------- */
#topbar {
  position: fixed;
  top: 0; left: 0; right: 0;
  height: 52px;
  z-index: 40;
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 0 16px;
  background: linear-gradient(180deg, rgba(13,17,23,0.92), rgba(13,17,23,0.55));
  border-bottom: 1px solid var(--border);
  backdrop-filter: blur(8px);
}
.brand { display: flex; flex-direction: column; line-height: 1.1; min-width: 150px; }
.brand .title { font-size: 18px; font-weight: 700; letter-spacing: 1px; }
.brand .subtitle { font-size: 11px; color: var(--fg-dim); letter-spacing: 2px; }

#search-wrap { position: relative; flex: 1; max-width: 480px; }
#search-input {
  width: 100%;
  height: 32px;
  padding: 0 14px;
  border-radius: 16px;
  border: 1px solid var(--border);
  background: rgba(255,255,255,0.06);
  color: var(--fg);
  font-size: 14px;
  outline: none;
  transition: border-color .15s, box-shadow .15s;
}
#search-input:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(88,166,255,0.15);
}
#search-input::placeholder { color: var(--fg-dim); }
#search-results {
  position: absolute;
  top: 38px; left: 0; right: 0;
  max-height: 380px;
  overflow-y: auto;
  border-radius: 10px;
  background: var(--bg-elev);
  box-shadow: var(--shadow);
  border: 1px solid var(--border);
  z-index: 50;
}
.sr-item {
  padding: 9px 14px;
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 10px;
  border-bottom: 1px solid rgba(255,255,255,0.04);
}
.sr-item:hover, .sr-item.active { background: rgba(88,166,255,0.12); }
.sr-dot { width: 9px; height: 9px; border-radius: 50%; flex: none; }
.sr-name { font-size: 14px; }
.sr-meta { font-size: 12px; color: var(--fg-dim); margin-left: auto; white-space: nowrap; }
.sr-empty { padding: 12px 14px; color: var(--fg-dim); font-size: 13px; }

.actions { display: flex; align-items: center; gap: 8px; margin-left: auto; }
.btn {
  height: 30px;
  padding: 0 12px;
  border-radius: 8px;
  border: 1px solid var(--border);
  background: rgba(255,255,255,0.05);
  color: var(--fg);
  font-size: 13px;
  cursor: pointer;
  transition: background .15s, border-color .15s;
  white-space: nowrap;
}
.btn:hover { background: rgba(255,255,255,0.12); }
.btn.active {
  background: rgba(88,166,255,0.18);
  border-color: var(--accent);
  color: var(--accent);
}
#stat { font-size: 12px; color: var(--fg-dim); white-space: nowrap; }

/* 紧凑控件（字号/间距滑杆） */
.ctl {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 12px;
  color: var(--fg-dim);
  white-space: nowrap;
}
.ctl input[type="range"] {
  -webkit-appearance: none;
  appearance: none;
  width: 92px;
  height: 4px;
  border-radius: 2px;
  background: rgba(255,255,255,0.18);
  outline: none;
  cursor: pointer;
}
.ctl input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background: var(--accent);
  border: 2px solid #fff;
  cursor: pointer;
}
.ctl input[type="range"]::-moz-range-thumb {
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: var(--accent);
  border: 2px solid #fff;
  cursor: pointer;
}

/* ---------------- 图容器 ---------------- */
#graph3d, #graph2d {
  position: fixed;
  top: 52px; left: 0; right: 0; bottom: 0;
  z-index: 10;
}
#graph2d { z-index: 12; right: 440px; }  /* 2D 模式下详情面板常驻右侧，画布避开面板以免节点被遮挡而无法点击 */

/* 2D 顶部提示条 */
#hint2d {
  position: fixed;
  top: 64px; left: calc((100% - 440px) / 2);
  transform: translateX(-50%);
  z-index: 30;
  padding: 6px 14px;
  border-radius: 20px;
  background: rgba(22,27,34,0.8);
  border: 1px solid var(--border);
  font-size: 13px;
  color: var(--fg-dim);
  pointer-events: none;
  backdrop-filter: blur(6px);
}

/* ---------------- 领域图例 ---------------- */
#cloud-legend {
  position: fixed;
  top: 64px; right: 16px;
  z-index: 35;
  width: 220px;
  max-height: 70vh;
  overflow-y: auto;
  padding: 12px;
  border-radius: 12px;
  background: var(--bg-elev);
  border: 1px solid var(--border);
  box-shadow: var(--shadow);
}
#cloud-legend .lg-title { font-size: 13px; font-weight: 700; margin-bottom: 8px; color: var(--fg-dim); letter-spacing: 1px; }
.lg-item {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 5px 6px;
  border-radius: 6px;
  cursor: pointer;
  font-size: 13px;
  user-select: none;
}
.lg-item:hover { background: rgba(255,255,255,0.06); }
.lg-item.off { opacity: 0.35; }
.lg-swatch { width: 12px; height: 12px; border-radius: 3px; flex: none; }
.lg-count { margin-left: auto; color: var(--fg-dim); font-size: 12px; }
.lg-tip { font-size: 11px; color: var(--fg-dim); margin-top: 8px; line-height: 1.5; }

/* ---------------- 分类高亮侧边栏（3D，多选） ---------------- */
#domain-panel {
  position: fixed;
  top: 64px; right: 16px;
  z-index: 35;
  width: 260px;
  max-height: 70vh;
  overflow-y: auto;
  padding: 12px;
  border-radius: 12px;
  background: var(--bg-elev);
  border: 1px solid var(--border);
  box-shadow: var(--shadow);
}
.dp-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
  margin-bottom: 8px;
}
.dp-actions { display: flex; gap: 6px; }
.dp-btn { height: 22px; padding: 0 8px; font-size: 11px; }
.dp-item {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 4px 6px;
  border-radius: 6px;
  cursor: pointer;
  font-size: 13px;
  user-select: none;
}
.dp-item:hover { background: rgba(255,255,255,0.06); }
.dp-item input { accent-color: #58a6ff; cursor: pointer; flex: none; }
.dp-name { overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
/* 分类高亮激活时按钮常亮提示 */
#btn-domain-hl.on { border-color: #58a6ff; color: #b5dcff; }

/* ---------------- 详情抽屉 ---------------- */
#detail {
  position: fixed;
  top: 52px; right: 0; bottom: 0;
  width: 440px;
  max-width: 92vw;
  z-index: 45;
  background: var(--bg-panel);
  border-left: 1px solid var(--border);
  box-shadow: var(--shadow);
  backdrop-filter: blur(10px);
  display: flex;
  flex-direction: column;
  transform: translateX(0);
  transition: transform .25s ease;
}
#detail.closed { transform: translateX(105%); }

#detail-head {
  flex: none;
  padding: 14px 18px 10px;
  border-bottom: 1px solid var(--border);
  position: relative;
}
#detail-title { font-size: 20px; font-weight: 700; line-height: 1.3; padding-right: 40px; }
#detail-title .en { font-size: 13px; color: var(--fg-dim); font-weight: 400; margin-left: 8px; }
#detail-sub { margin-top: 6px; display: flex; align-items: center; gap: 8px; flex-wrap: wrap; }
.badge-domain {
  font-size: 12px;
  padding: 2px 10px;
  border-radius: 12px;
  color: #fff;
}
.alias-list { font-size: 12px; color: var(--fg-dim); }
#detail-close {
  position: absolute;
  top: 12px; right: 12px;
  width: 28px; height: 28px;
  border-radius: 50%;
  border: 1px solid var(--border);
  background: transparent;
  color: var(--fg-dim);
  font-size: 14px;
  cursor: pointer;
}
#detail-close:hover { background: rgba(255,255,255,0.1); color: var(--fg); }

#detail-scroll {
  flex: 1;
  overflow-y: auto;
  padding: 4px 18px 20px;
}

/* 正文 */
.sec-body { margin: 10px 0; }
.sec-body h1, .sec-body h2, .sec-body h3 { margin: 14px 0 6px; font-size: 16px; color: var(--fg); }
.sec-body h1 { font-size: 18px; }
.sec-body h2 { font-size: 16px; border-bottom: 1px solid var(--border); padding-bottom: 4px; }
.sec-body h3 { font-size: 14px; color: var(--accent); }
.sec-body p { font-size: 14px; line-height: 1.85; margin: 6px 0; color: #dbe4ee; }
.sec-body ul, .sec-body ol { margin: 6px 0 6px 22px; font-size: 14px; line-height: 1.8; color: #dbe4ee; }
.sec-body li { margin: 3px 0; }
.sec-body blockquote { margin: 8px 0; padding: 8px 12px; border-left: 3px solid var(--accent); background: rgba(255,255,255,0.04); font-size: 13px; color: var(--fg-dim); }
.sec-body code { background: rgba(255,255,255,0.08); padding: 1px 5px; border-radius: 4px; font-size: 13px; font-family: Consolas, monospace; }
.sec-body pre { background: rgba(255,255,255,0.05); padding: 10px; border-radius: 8px; overflow-x: auto; margin: 8px 0; }
.sec-body pre code { background: none; padding: 0; }
.sec-body table { border-collapse: collapse; margin: 8px 0; font-size: 13px; }
.sec-body th, .sec-body td { border: 1px solid var(--border); padding: 5px 10px; }
.sec-body strong { color: #fff; }
.jump-link {
  color: var(--accent);
  text-decoration: none;
  border-bottom: 1px dashed rgba(88,166,255,0.5);
  cursor: pointer;
}
.jump-link:hover { color: #79c0ff; }

/* 相关节点区块 */
.sec-links { margin: 8px 0; }
.sec-links .lbl { font-size: 13px; font-weight: 700; letter-spacing: 1px; margin: 14px 0 8px; color: var(--fg-dim); }
.link-card {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 8px 10px;
  margin: 6px 0;
  border-radius: 8px;
  background: rgba(255,255,255,0.04);
  border: 1px solid rgba(255,255,255,0.05);
  cursor: pointer;
  transition: background .15s, border-color .15s;
}
.link-card:hover { background: rgba(88,166,255,0.1); border-color: rgba(88,166,255,0.35); }
.link-card .nm { font-size: 14px; color: var(--fg); }
.link-card .wtag {
  font-size: 11px;
  color: var(--accent);
  border: 1px solid rgba(88,166,255,0.4);
  border-radius: 8px;
  padding: 0 6px;
  flex: none;
}
.link-card .note { font-size: 12px; color: var(--fg-dim); margin-top: 2px; }
.link-card .arrow { margin-left: auto; color: var(--fg-dim); font-size: 13px; }
.link-card.soft { opacity: 0.75; border-style: dashed; }
.link-card.prereq { border-color: rgba(88,166,255,0.30); }
.link-card.prereq .nm { color: var(--accent); }
.link-card .wtag.rel { color: var(--fg-dim); border-color: var(--border); }

.sec-foot {
  margin: 18px 0 8px;
  padding-top: 12px;
  border-top: 1px solid var(--border);
  font-size: 12px;
  color: var(--fg-dim);
  line-height: 1.8;
}

/* ---------------- 树状学习图面板 ---------------- */
#tree-panel {
  position: fixed;
  top: 52px; left: 0; bottom: 0;
  width: 280px;
  z-index: 20;
  display: flex;
  flex-direction: column;
  background: var(--bg-panel);
  border-right: 1px solid var(--border);
  box-shadow: var(--shadow);
  backdrop-filter: blur(10px);
}
#tree-head {
  flex: none;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 10px 12px;
  border-bottom: 1px solid var(--border);
}
#tree-head .th-title { font-size: 13px; font-weight: 700; letter-spacing: 1px; }
#tree-head .th-actions { display: flex; gap: 4px; }
#tree-head .btn { height: 24px; padding: 0 8px; font-size: 11px; }

/* 保存输入框 */
#tree-save-box {
  flex: none;
  display: flex;
  gap: 6px;
  padding: 8px 12px;
  border-bottom: 1px solid var(--border);
  background: rgba(0,0,0,0.18);
}
#tree-save-box input {
  flex: 1;
  min-width: 0;
  height: 26px;
  padding: 0 8px;
  border-radius: 6px;
  border: 1px solid var(--border);
  background: rgba(255,255,255,0.08);
  color: var(--fg);
  font-size: 12px;
  outline: none;
}
#tree-save-box input:focus { border-color: var(--accent); }
#tree-save-box .btn { height: 26px; padding: 0 8px; font-size: 11px; }

/* 森林下拉 */
#tree-forest {
  flex: none;
  max-height: 200px;
  overflow-y: auto;
  border-bottom: 1px solid var(--border);
  background: var(--bg-elev);
}
.ff-empty { padding: 12px 14px; font-size: 12px; color: var(--fg-dim); }
.ff-item {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 8px 12px;
  font-size: 12px;
  cursor: pointer;
  border-bottom: 1px solid rgba(255,255,255,0.04);
}
.ff-item:hover { background: rgba(88,166,255,0.1); }
.ff-name { flex: 1; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; color: var(--fg); }
.ff-meta { color: var(--fg-dim); font-size: 11px; white-space: nowrap; }
.ff-del {
  flex: none;
  width: 18px; height: 18px;
  border: none; border-radius: 4px;
  background: transparent; color: var(--fg-dim);
  font-size: 13px; line-height: 1; cursor: pointer;
}
.ff-del:hover { background: rgba(255,255,255,0.14); color: #fff; }

#tree-list { flex: 1; overflow-y: auto; padding: 6px 0 12px; }
#tree-empty {
  padding: 18px 14px;
  font-size: 12px;
  color: var(--fg-dim);
  line-height: 1.7;
}

.tree-item {
  display: flex;
  align-items: center;
  gap: 5px;
  height: 30px;
  padding: 0 10px 0 0;
  font-size: 13px;
  color: var(--fg);
  cursor: pointer;
  user-select: none;
  white-space: nowrap;
}
.tree-item:hover { background: rgba(255,255,255,0.06); }
.tree-item.dragging { opacity: 0.4; }
.tree-item.drop-target { background: rgba(88,166,255,0.18); outline: 1px dashed var(--accent); outline-offset: -1px; }
.tree-item.current { background: rgba(88,166,255,0.14); }
.tree-item.current .ti-name { color: var(--accent); font-weight: 700; }
.tree-item.root .ti-name { color: #fff; font-weight: 700; }
.tree-item.weak, .tree-item.hyper { opacity: 0.55; }
.tree-item.weak:hover, .tree-item.hyper:hover { opacity: 0.8; }

.ti-indent { flex: none; height: 1px; }
.ti-toggle { flex: none; width: 16px; text-align: center; color: var(--fg-dim); font-size: 11px; }
.ti-toggle.leaf { visibility: hidden; }
.ti-dot { flex: none; width: 9px; height: 9px; border-radius: 50%; }
.ti-name { flex: 1; overflow: hidden; text-overflow: ellipsis; }
.ti-actions { flex: none; display: none; gap: 2px; }
.tree-item:hover .ti-actions { display: flex; }
.ti-btn {
  width: 18px; height: 18px;
  border: none; border-radius: 4px;
  background: transparent; color: var(--fg-dim);
  font-size: 12px; line-height: 1; cursor: pointer;
}
.ti-btn:hover { background: rgba(255,255,255,0.14); color: #fff; }

/* 建新根询问弹窗 */
#tree-prompt {
  position: fixed;
  top: 80px; left: 50%;
  transform: translateX(-50%);
  z-index: 220;
  width: 340px;
  max-width: 92vw;
  padding: 14px 16px;
  border-radius: 12px;
  background: var(--bg-elev);
  border: 1px solid var(--border);
  box-shadow: var(--shadow);
}
#tree-prompt .tp-text { font-size: 13px; line-height: 1.7; margin-bottom: 10px; }
#tree-prompt .tp-btns { display: flex; gap: 8px; justify-content: flex-end; }

/* ---------------- 加载遮罩 ---------------- */
#loading {
  position: fixed;
  inset: 0;
  z-index: 100;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--bg);
  color: var(--fg-dim);
  font-size: 14px;
  letter-spacing: 2px;
  transition: opacity .4s;
}
#loading.fade { opacity: 0; pointer-events: none; }

/* ---------------- 滚动条 ---------------- */
::-webkit-scrollbar { width: 8px; height: 8px; }
::-webkit-scrollbar-thumb { background: rgba(255,255,255,0.14); border-radius: 4px; }
::-webkit-scrollbar-thumb:hover { background: rgba(255,255,255,0.24); }
::-webkit-scrollbar-track { background: transparent; }

/* ---------------- KaTeX 微调 ---------------- */
.katex { font-size: 1.12em; }
.katex-display { margin: 10px 0; overflow-x: auto; overflow-y: hidden; padding: 4px 0; }

@media (max-width: 720px) {
  .brand .subtitle { display: none; }
  .brand { min-width: 90px; }
  #stat { display: none; }
  #detail { width: 100vw; max-width: 100vw; }
  #graph2d { right: 0; }
  #hint2d { left: 50%; }
  #tree-panel { width: 100vw; }
}