/* ============================================================
   《坩埚》 CRUCIBLE — Kotlin 进阶小书 · 熔炉铸造风设计系统
   一间铸造车间:砂型米白、铁灰墨、Kotlin 紫→橙红熔融渐变。
   亮色 only(用户眼睛受不了暗色)。零依赖,系统字体栈。
   ============================================================ */

:root {
  /* —— 砂型与铁 —— */
  --sand: #F7F4EE;           /* 砂型米白(纸底) */
  --sand-deep: #EFEAE0;      /* 卡片、模具 */
  --sand-dim: #E3DCCE;       /* 分隔、砂线 */
  --iron: #23262E;           /* 铸铁墨(标题/重点) */
  --iron-body: #3C414C;      /* 正文 */
  --iron-faint: #767D8B;     /* 次要标注 */
  --line: #D9D3C6;           /* 型廓线 */

  /* —— 炉火 —— */
  --purple: #7F52FF;         /* Kotlin 紫(关键字/主强调) */
  --purple-deep: #5B32C9;
  --purple-mist: #F0EBFF;
  --ember: #E44857;          /* 橙红(熔融/热点) */
  --ember-deep: #C0392B;
  --ember-mist: #FDECEC;
  --slag: #B4622A;           /* 炉渣赭(陷阱/警示) */
  --slag-mist: #F9EEE3;
  --steel: #4A5A73;          /* 钢蓝(旧模具 · Java 对照) */
  --steel-mist: #EAEEF4;
  --anvil: #3E7C59;          /* 砧绿(练习/通过) */
  --anvil-mist: #E7F0E8;

  /* —— 代码 token —— */
  --tok-kw: #7F52FF;
  --tok-type: #1F6F8B;
  --tok-str: #3E7C59;
  --tok-num: #B0561F;
  --tok-com: #8C93A0;
  --tok-op: #C0512A;
  --tok-fn: #23262E;
  --tok-ann: #B4622A;

  --serif: "Songti SC", "STSong", "Noto Serif SC", "Source Han Serif SC", Georgia, "Times New Roman", serif;
  --sans: -apple-system, BlinkMacSystemFont, "PingFang SC", "Hiragino Sans GB", "Source Han Sans SC", "Noto Sans SC", "Microsoft YaHei", sans-serif;
  --mono: ui-monospace, "SF Mono", "JetBrains Mono", "Fira Code", Menlo, Consolas, "Liberation Mono", monospace;

  --topbar-h: 56px;
  --maxw: 780px;
}

* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }
html, body { overflow-x: hidden; }

body {
  font-family: var(--sans);
  background-color: var(--sand);
  /* 砂型纹理:细颗粒 + 极淡的型砂划痕 */
  background-image:
    url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='160' height='160' viewBox='0 0 160 160'%3E%3Cg fill='%2323262E' fill-opacity='0.035'%3E%3Ccircle cx='12' cy='23' r='1'/%3E%3Ccircle cx='47' cy='9' r='0.8'/%3E%3Ccircle cx='83' cy='31' r='1.1'/%3E%3Ccircle cx='119' cy='16' r='0.9'/%3E%3Ccircle cx='148' cy='44' r='1'/%3E%3Ccircle cx='27' cy='62' r='0.9'/%3E%3Ccircle cx='66' cy='77' r='1'/%3E%3Ccircle cx='103' cy='58' r='0.8'/%3E%3Ccircle cx='136' cy='92' r='1.1'/%3E%3Ccircle cx='18' cy='108' r='1'/%3E%3Ccircle cx='54' cy='127' r='0.9'/%3E%3Ccircle cx='92' cy='113' r='1'/%3E%3Ccircle cx='127' cy='140' r='0.9'/%3E%3Ccircle cx='38' cy='150' r='1'/%3E%3Ccircle cx='73' cy='45' r='0.7'/%3E%3Ccircle cx='157' cy='121' r='0.8'/%3E%3C/g%3E%3C/svg%3E");
  color: var(--iron-body);
  line-height: 1.9;
  font-size: 16.5px;
  padding-top: var(--topbar-h);
}

::selection { background: rgba(127, 82, 255, 0.18); }

a { color: var(--purple-deep); text-decoration: none; border-bottom: 1px solid rgba(127, 82, 255, 0.35); }
a:hover { color: var(--ember); border-bottom-color: var(--ember); }

code {
  font-family: var(--mono);
  font-size: 0.86em;
  background: rgba(35, 38, 46, 0.06);
  border-radius: 4px;
  padding: 0.1em 0.4em;
  color: var(--iron);
  word-break: break-word;
}

strong { color: var(--iron); }
em { font-style: normal; color: var(--purple-deep); }

/* ============ 顶部炉台条(fixed) ============ */
.topbar {
  position: fixed; top: 0; left: 0; right: 0; z-index: 90;
  height: var(--topbar-h);
  background: rgba(247, 244, 238, 0.93);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--line);
  display: flex; align-items: center; gap: 14px;
  padding: 0 18px;
}
.topbar .brand {
  font-family: var(--serif);
  font-weight: 700; font-size: 19px; letter-spacing: 0.22em;
  color: var(--iron); border: none; white-space: nowrap;
  display: flex; align-items: center; gap: 9px;
}
.topbar .brand:hover { color: var(--purple-deep); }
.topbar .brand .mark {
  font-family: var(--mono); font-weight: 700; font-size: 13px;
  color: #fff; background: linear-gradient(135deg, var(--purple), var(--ember));
  width: 24px; height: 24px; border-radius: 6px;
  display: inline-flex; align-items: center; justify-content: center;
  letter-spacing: 0;
}
/* 浇道进度(铁水沿浇道推进) */
.topbar .runner-wrap { flex: 1; min-width: 60px; height: 100%; position: relative; display: flex; align-items: center; }
.topbar .runner-wrap svg { width: 100%; height: 32px; display: block; }
.topbar .runner-bed { fill: var(--sand-dim); }
.topbar .runner-tick { fill: rgba(35, 38, 46, 0.22); }
.topbar .runner-front { filter: drop-shadow(0 0 3px rgba(228, 72, 87, 0.65)); }
.topbar .runner-label {
  position: absolute; bottom: 2px; font-family: var(--mono);
  font-size: 9px; letter-spacing: 0.12em; color: var(--iron-faint);
  user-select: none; pointer-events: none;
}
.topbar .runner-label.start { left: 0; }
.topbar .runner-label.end { right: 0; }
.topbar .ch-pos {
  font-family: var(--mono); font-size: 11px; letter-spacing: 0.1em;
  color: var(--iron-faint); white-space: nowrap;
}
.topbar .ch-pos b { color: var(--ember-deep); font-weight: 600; }
.topbar .toc-btn {
  font-family: var(--mono); font-size: 11.5px; letter-spacing: 0.14em;
  color: var(--iron); background: transparent;
  border: 1px solid var(--line); border-radius: 6px;
  padding: 6px 13px; cursor: pointer; white-space: nowrap;
}
.topbar .toc-btn:hover { border-color: var(--purple); color: var(--purple-deep); background: var(--purple-mist); }
@media (max-width: 640px) {
  .topbar { gap: 10px; padding: 0 12px; }
  .topbar .ch-pos { display: none; }
  .topbar .runner-label { display: none; }
}

/* ============ 目录覆盖层:炉次清单 ============ */
.toc-overlay {
  position: fixed; inset: 0; z-index: 200;
  background: rgba(247, 244, 238, 0.985);
  overflow-y: auto;
  opacity: 0; pointer-events: none;
  transition: opacity 0.22s ease;
}
.toc-overlay.open { opacity: 1; pointer-events: auto; }
.toc-inner { max-width: 700px; margin: 0 auto; padding: 60px 22px 90px; }
.toc-head { display: flex; align-items: baseline; justify-content: space-between; margin-bottom: 8px; }
.toc-head h2 {
  font-family: var(--serif); font-size: 30px; letter-spacing: 0.3em;
  color: var(--iron); font-weight: 700;
}
.toc-head .close {
  font-family: var(--mono); font-size: 12px; color: var(--iron-faint);
  background: none; border: 1px solid var(--line); border-radius: 6px;
  padding: 6px 12px; cursor: pointer;
}
.toc-head .close:hover { color: var(--ember); border-color: var(--ember); }
.toc-sub { font-family: var(--mono); font-size: 11px; letter-spacing: 0.18em; color: var(--iron-faint); margin-bottom: 34px; }

.toc-vol { position: relative; padding-left: 34px; margin-bottom: 8px; }
/* 纵向浇道线 */
.toc-vol::before {
  content: ""; position: absolute; left: 10px; top: 6px; bottom: -8px;
  width: 3px; border-radius: 2px;
  background: linear-gradient(to bottom, var(--purple) 0%, var(--ember) 100%);
  opacity: 0.55;
}
.toc-vol:last-child::before { bottom: 12px; }
/* 炉口圆标 */
.toc-vol::after {
  content: ""; position: absolute; left: 4px; top: 8px;
  width: 15px; height: 15px; border-radius: 50%;
  background: var(--sand); border: 3px solid var(--purple);
}
.toc-vol .vol-name {
  font-family: var(--mono); font-size: 11.5px; letter-spacing: 0.2em;
  color: var(--purple-deep); font-weight: 600; margin-bottom: 2px;
}
.toc-vol .vol-desc { font-size: 13px; color: var(--iron-faint); margin-bottom: 12px; }
.toc-vol ol { list-style: none; margin-bottom: 26px; }
.toc-vol li a {
  display: flex; align-items: baseline; gap: 12px;
  padding: 7px 10px; border: none; border-radius: 7px;
  color: var(--iron-body); font-size: 15px;
}
.toc-vol li a:hover { background: var(--purple-mist); color: var(--purple-deep); }
.toc-vol li a .no { font-family: var(--mono); font-size: 11px; color: var(--iron-faint); min-width: 22px; }
.toc-vol li a .demo-tag {
  margin-left: auto; font-family: var(--mono); font-size: 9.5px; letter-spacing: 0.08em;
  color: var(--ember-deep); border: 1px solid rgba(228, 72, 87, 0.4);
  border-radius: 4px; padding: 1px 6px; white-space: nowrap;
}
.toc-vol li a.cur { background: var(--purple-mist); color: var(--purple-deep); font-weight: 600; }
.toc-vol li a.cur .no { color: var(--purple); }

/* ============ 章节页骨架 ============ */
.content { display: block; }
.wrap { max-width: var(--maxw); margin: 0 auto; padding: 0 22px; }

.chapter-head { padding: 58px 0 10px; }
.chapter-head .kicker {
  display: flex; align-items: center; gap: 10px; flex-wrap: wrap;
  font-family: var(--mono); font-size: 11px; letter-spacing: 0.18em;
  color: var(--iron-faint); margin-bottom: 18px;
}
.chapter-head .kicker .vol { color: var(--purple-deep); font-weight: 600; }
.chapter-head .kicker .heat { color: var(--ember-deep); }
.chapter-head .kicker .sep { width: 26px; height: 1px; background: var(--line); }
.chapter-head h1 {
  font-family: var(--serif); font-size: 40px; line-height: 1.35;
  color: var(--iron); font-weight: 700; letter-spacing: 0.02em;
  margin-bottom: 20px;
}
.chapter-head h1 em { font-style: normal; color: var(--ember-deep); }
.chapter-head .lede {
  font-size: 17px; line-height: 2.0; color: var(--iron-body);
  border-left: 3px solid transparent;
  border-image: linear-gradient(to bottom, var(--purple), var(--ember)) 1;
  padding-left: 18px;
  margin-bottom: 22px;
}
.chapter-head .tags { display: flex; gap: 8px; flex-wrap: wrap; }
.chapter-head .tags span {
  font-family: var(--mono); font-size: 10.5px; letter-spacing: 0.1em;
  color: var(--purple-deep); background: var(--purple-mist);
  border-radius: 5px; padding: 3px 10px;
}
.headrule {
  border: none; height: 3px; margin: 34px 0 8px; border-radius: 2px;
  background: linear-gradient(to right, var(--purple), var(--ember) 55%, rgba(228, 72, 87, 0) 100%);
  opacity: 0.65;
}

/* ============ 正文排印 ============ */
.prose { padding-bottom: 30px; }
.prose h2 {
  font-family: var(--serif); font-size: 26px; color: var(--iron);
  font-weight: 700; line-height: 1.5;
  margin: 54px 0 18px; padding-bottom: 10px;
  border-bottom: 1px solid var(--line);
  position: relative;
}
.prose h2::after {
  content: ""; position: absolute; left: 0; bottom: -1px;
  width: 64px; height: 2px;
  background: linear-gradient(to right, var(--purple), var(--ember));
}
.prose h3 {
  font-family: var(--serif); font-size: 20px; color: var(--iron);
  font-weight: 700; margin: 38px 0 14px;
  display: flex; align-items: center; gap: 10px;
}
.prose h3::before { content: "▍"; color: var(--ember); font-size: 15px; }
.prose p { margin: 0 0 18px; }
.prose ul, .prose ol { margin: 0 0 18px; padding-left: 26px; }
.prose li { margin-bottom: 8px; }
.prose li::marker { color: var(--purple); font-family: var(--mono); font-size: 0.9em; }
.prose hr { border: none; border-top: 1px dashed var(--line); margin: 40px 0; }

.prose table {
  width: 100%; border-collapse: collapse; margin: 22px 0;
  font-size: 14.5px; line-height: 1.75;
  background: rgba(255, 255, 255, 0.55);
}
.prose th, .prose td { border: 1px solid var(--line); padding: 9px 13px; text-align: left; vertical-align: top; }
.prose th {
  font-family: var(--mono); font-size: 11.5px; letter-spacing: 0.1em;
  color: var(--iron); background: var(--sand-deep); font-weight: 600;
  white-space: nowrap;
}
.table-scroll { overflow-x: auto; }
.table-scroll table { min-width: 560px; }

/* ============ callout 卡(炉边标记) ============ */
.co {
  border-radius: 10px; padding: 16px 20px 14px; margin: 24px 0;
  border: 1px solid; border-left-width: 4px;
  background: rgba(255, 255, 255, 0.5);
  font-size: 15.2px; line-height: 1.95;
}
.co .co-t {
  font-family: var(--mono); font-size: 11px; letter-spacing: 0.2em;
  font-weight: 700; margin-bottom: 8px; display: flex; align-items: center; gap: 8px;
}
.co p { margin-bottom: 10px; }
.co p:last-child { margin-bottom: 2px; }
.co code { background: rgba(35, 38, 46, 0.07); }
.co ul, .co ol { margin: 0 0 10px; padding-left: 22px; }
.co li { margin-bottom: 6px; }

/* ◆ 锭:核心结论(值得带走的那一块金属) */
.co.ingot { border-color: rgba(127, 82, 255, 0.4); border-left-color: var(--purple); background: var(--purple-mist); }
.co.ingot .co-t { color: var(--purple-deep); }
/* ▸ 旧模具:Java 对照 */
.co.java { border-color: rgba(74, 90, 115, 0.35); border-left-color: var(--steel); background: var(--steel-mist); }
.co.java .co-t { color: var(--steel); }
/* ⚠ 炉渣:陷阱与坑 */
.co.slag { border-color: rgba(180, 98, 42, 0.45); border-left-color: var(--slag); background: var(--slag-mist); }
.co.slag .co-t { color: var(--slag); }
/* ✦ 新炉料:2.x 新特性(带版本与稳定状态) */
.co.new { border-color: rgba(228, 72, 87, 0.4); border-left-color: var(--ember); background: var(--ember-mist); }
.co.new .co-t { color: var(--ember-deep); }
/* ✚ 动手锻打:练习 */
.co.forge { border-color: rgba(62, 124, 89, 0.45); border-left-color: var(--anvil); background: var(--anvil-mist); }
.co.forge .co-t { color: var(--anvil); }

/* 版本徽章:标在新特性上 */
.ver {
  font-family: var(--mono); font-size: 10px; letter-spacing: 0.08em;
  border-radius: 4px; padding: 1px 7px; white-space: nowrap;
  vertical-align: 0.12em; margin-left: 2px; font-weight: 600;
}
.ver.stable { color: #fff; background: var(--anvil); }
.ver.exp { color: #fff; background: var(--slag); }
.ver.beta { color: #fff; background: var(--steel); }

/* ============ 代码块 ============ */
pre {
  font-family: var(--mono); font-size: 13.5px; line-height: 1.8;
  border-radius: 10px; padding: 18px 20px; margin: 22px 0;
  overflow-x: auto; position: relative;
  white-space: pre; tab-size: 4;
}
pre .tag-corner {
  position: absolute; top: 0; right: 0;
  font-size: 9.5px; letter-spacing: 0.14em; font-weight: 600;
  padding: 3px 10px; border-radius: 0 9px 0 8px;
  user-select: none;
}

/* Kotlin 源码:白纸铸件卡 */
pre.code {
  background: #FFFFFF; color: var(--iron-body);
  border: 1px solid var(--line);
  box-shadow: 0 1px 0 rgba(35, 38, 46, 0.05);
}
pre.code .tag-corner { color: #fff; background: linear-gradient(135deg, var(--purple), var(--ember)); }

/* Java / 旧模具对照:钢灰纸 */
pre.java {
  background: var(--steel-mist); color: var(--iron-body);
  border: 1px solid rgba(74, 90, 115, 0.28);
}
pre.java .tag-corner { color: #fff; background: var(--steel); }

/* JVM 伪码 / 反编译结果:模具砂 */
pre.jvm {
  background: var(--sand-deep); color: var(--iron-body);
  border: 1px solid var(--line);
}
pre.jvm .tag-corner { color: var(--iron); background: var(--sand-dim); }

/* 编译器输出 / 报错:炉渣 */
pre.out {
  background: var(--slag-mist); color: var(--iron-body);
  border: 1px solid rgba(180, 98, 42, 0.3);
}
pre.out .tag-corner { color: #fff; background: var(--slag); }
pre.out .oerr { color: var(--ember-deep); font-weight: 600; }
pre.out .ook { color: var(--anvil); }
pre.out .odim { color: var(--iron-faint); }

/* 高亮 token */
.tk-kw { color: var(--tok-kw); font-weight: 600; }
.tk-ty { color: var(--tok-type); font-weight: 600; }
.tk-st { color: var(--tok-str); }
.tk-nu { color: var(--tok-num); }
.tk-co { color: var(--tok-com); font-style: italic; }
.tk-op { color: var(--tok-op); }
.tk-fn { color: var(--tok-fn); font-weight: 600; }
.tk-an { color: var(--tok-ann); font-weight: 600; }
/* 行内强调:demo 中标红/标紫的关键行 */
.hl-hot { background: rgba(228, 72, 87, 0.14); border-radius: 3px; }
.hl-cold { background: rgba(127, 82, 255, 0.12); border-radius: 3px; }

/* ============ Demo 部件 ============ */
.demo {
  border: 1.5px solid var(--purple); border-radius: 12px;
  margin: 30px 0; background: #fff;
  box-shadow: 0 2px 0 rgba(91, 50, 201, 0.12);
  overflow: hidden;
}
.demo-head {
  display: flex; align-items: center; gap: 10px;
  background: linear-gradient(to right, var(--purple-mist), rgba(253, 236, 236, 0.55));
  border-bottom: 1px solid rgba(127, 82, 255, 0.2);
  padding: 9px 16px;
  font-family: var(--mono); font-size: 11px; letter-spacing: 0.16em;
  color: var(--purple-deep); font-weight: 600;
}
.demo-head .heat {
  width: 10px; height: 10px; border-radius: 50%; flex: none;
  background: linear-gradient(135deg, var(--purple), var(--ember));
  box-shadow: 0 0 0 3px rgba(228, 72, 87, 0.16);
  animation: heat-pulse 2.4s ease-in-out infinite;
}
@keyframes heat-pulse {
  0%, 100% { box-shadow: 0 0 0 3px rgba(228, 72, 87, 0.16); }
  50% { box-shadow: 0 0 0 5px rgba(228, 72, 87, 0.08); }
}
.demo-head .d-hint { margin-left: auto; color: var(--iron-faint); font-weight: 400; letter-spacing: 0.08em; font-size: 10px; }
.demo-body { padding: 16px; }

.d-row { display: flex; gap: 10px; flex-wrap: wrap; align-items: center; margin-bottom: 12px; }
.d-row:last-child { margin-bottom: 0; }
.d-btn {
  font-family: var(--mono); font-size: 12px; letter-spacing: 0.06em;
  background: var(--purple); color: #fff;
  border: none; border-radius: 7px; padding: 7px 15px; cursor: pointer;
}
.d-btn:hover { background: var(--purple-deep); }
.d-btn:disabled { background: var(--sand-dim); color: var(--iron-faint); cursor: not-allowed; }
.d-btn.ghost { background: transparent; color: var(--purple-deep); border: 1px solid var(--purple); }
.d-btn.ghost:hover { background: var(--purple-mist); }
.d-btn.hot { background: var(--ember); }
.d-btn.hot:hover { background: var(--ember-deep); }
.d-btn.molten { background: linear-gradient(135deg, var(--purple), var(--ember)); }
.d-btn.molten:hover { filter: brightness(0.94); }

/* 示例切换 chips(本书 demo 主控件) */
.d-chips { display: flex; gap: 7px; flex-wrap: wrap; }
.d-chip {
  font-family: var(--mono); font-size: 11.5px;
  border: 1px solid var(--line); border-radius: 999px;
  background: #fff; color: var(--iron-body);
  padding: 5px 13px; cursor: pointer; white-space: nowrap;
  transition: all 0.14s ease;
}
.d-chip:hover { border-color: var(--purple); color: var(--purple-deep); }
.d-chip.on {
  background: linear-gradient(135deg, var(--purple), var(--ember));
  border-color: transparent; color: #fff; font-weight: 600;
}

.d-in, .d-sel, textarea.d-in {
  font-family: var(--mono); font-size: 13px;
  border: 1px solid var(--line); border-radius: 7px;
  background: var(--sand); color: var(--iron);
  padding: 7px 11px; outline: none;
}
.d-in:focus, .d-sel:focus, textarea.d-in:focus { border-color: var(--purple); background: #fff; }
.d-note { font-size: 12.5px; color: var(--iron-faint); line-height: 1.75; }
.d-note b { color: var(--iron); }
.d-err { font-family: var(--mono); font-size: 12.5px; color: var(--ember-deep); white-space: pre-wrap; }
.d-ok { font-family: var(--mono); font-size: 12.5px; color: var(--anvil); }

/* 左右对照(反编译台等) */
.d-split { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; }
.d-split > div { min-width: 0; }
.d-pane-t {
  font-family: var(--mono); font-size: 10px; letter-spacing: 0.14em;
  color: var(--iron-faint); margin-bottom: 6px; display: flex; align-items: center; gap: 6px;
}
.d-pane-t .dot { width: 7px; height: 7px; border-radius: 50%; }
.d-pane-t .dot.kt { background: var(--purple); }
.d-pane-t .dot.jv { background: var(--steel); }
.d-pane {
  font-family: var(--mono); font-size: 12.5px; line-height: 1.75;
  border-radius: 8px; padding: 12px 13px;
  overflow-x: auto; white-space: pre; tab-size: 4;
  border: 1px solid var(--line); background: #fff;
  min-height: 90px;
}
.d-pane.jv { background: var(--steel-mist); border-color: rgba(74, 90, 115, 0.25); }
@media (max-width: 620px) { .d-split { grid-template-columns: 1fr; } }

/* 步进器(状态机 / inline 展开) */
.d-steps { display: flex; align-items: center; gap: 8px; font-family: var(--mono); font-size: 11.5px; color: var(--iron-faint); }
.d-steps .cur { color: var(--ember-deep); font-weight: 700; }
.d-dots { display: flex; gap: 5px; }
.d-dots i {
  width: 9px; height: 9px; border-radius: 50%; display: block;
  background: var(--sand-dim); cursor: pointer;
}
.d-dots i.on { background: linear-gradient(135deg, var(--purple), var(--ember)); }
.d-dots i.done { background: rgba(127, 82, 255, 0.35); }

/* SVG 舞台(取消树 / 弹珠图 / 时间线) */
.d-stage { width: 100%; border: 1px solid var(--line); border-radius: 8px; background: var(--sand); overflow: hidden; }
.d-stage svg { display: block; width: 100%; height: auto; }

/* 键值/徽章 */
.d-kv { font-family: var(--mono); font-size: 12px; color: var(--iron-faint); }
.d-kv b { color: var(--purple-deep); font-weight: 600; }
.d-badge {
  font-family: var(--mono); font-size: 10.5px; letter-spacing: 0.08em;
  border-radius: 5px; padding: 2px 8px; white-space: nowrap;
}
.d-badge.ok { color: var(--anvil); background: var(--anvil-mist); border: 1px solid rgba(62,124,89,0.4); }
.d-badge.bad { color: var(--ember-deep); background: var(--ember-mist); border: 1px solid rgba(228,72,87,0.4); }
.d-badge.info { color: var(--purple-deep); background: var(--purple-mist); border: 1px solid rgba(127,82,255,0.35); }
.d-badge.warn { color: var(--slag); background: var(--slag-mist); border: 1px solid rgba(180,98,42,0.4); }

/* 状态格(状态空间计数) */
.d-states { display: flex; flex-wrap: wrap; gap: 6px; }
.d-states .st {
  font-family: var(--mono); font-size: 11px; border-radius: 6px;
  padding: 4px 9px; border: 1px solid var(--line); background: #fff; color: var(--iron-body);
}
.d-states .st.bad { border-color: rgba(228,72,87,0.5); background: var(--ember-mist); color: var(--ember-deep); text-decoration: line-through; }
.d-states .st.good { border-color: rgba(62,124,89,0.5); background: var(--anvil-mist); color: var(--anvil); }

/* 表格(用例 / 对照) */
.d-cases { width: 100%; border-collapse: collapse; font-family: var(--mono); font-size: 12px; }
.d-cases th, .d-cases td { border: 1px solid var(--line); padding: 5px 9px; text-align: left; }
.d-cases th { background: var(--sand-deep); font-weight: 600; letter-spacing: 0.06em; }
.d-cases tr.fail td { background: var(--ember-mist); color: var(--ember-deep); }
.d-cases-scroll { max-height: 280px; overflow: auto; border-radius: 6px; }

/* 决策树(作用域函数) */
.d-tree-q { font-size: 14.5px; color: var(--iron); margin-bottom: 10px; font-weight: 600; }
.d-path { font-family: var(--mono); font-size: 11.5px; color: var(--iron-faint); margin-bottom: 10px; }
.d-path span { color: var(--purple-deep); }
.d-verdict {
  border: 1px solid var(--purple); border-radius: 9px; padding: 13px 15px;
  background: var(--purple-mist);
}
.d-verdict .vt { font-family: var(--mono); font-size: 16px; color: var(--purple-deep); font-weight: 700; margin-bottom: 6px; }

/* 时间线(新特性巡礼) */
.d-line { position: relative; padding-left: 26px; }
.d-line::before {
  content: ""; position: absolute; left: 6px; top: 4px; bottom: 4px; width: 2px;
  background: linear-gradient(to bottom, var(--purple), var(--ember));
  border-radius: 2px; opacity: 0.5;
}
.d-item { position: relative; margin-bottom: 6px; }
.d-item::before {
  content: ""; position: absolute; left: -23px; top: 12px;
  width: 9px; height: 9px; border-radius: 50%;
  background: var(--sand); border: 2px solid var(--purple);
}
.d-item.on::before { background: var(--ember); border-color: var(--ember); }
.d-item-h {
  display: flex; align-items: center; gap: 8px; cursor: pointer;
  padding: 6px 8px; border-radius: 7px; font-size: 14.5px; color: var(--iron);
}
.d-item-h:hover { background: var(--sand-deep); }
.d-item-h .v { font-family: var(--mono); font-size: 11px; color: var(--ember-deep); font-weight: 600; min-width: 42px; }
.d-item-b { display: none; padding: 4px 8px 12px; }
.d-item.on .d-item-b { display: block; }

/* ============ 折叠问答(第 1、26 章的自检题) ============ */
.qa {
  border: 1px solid var(--line); border-left: 4px solid var(--purple);
  border-radius: 9px; margin: 12px 0; background: rgba(255, 255, 255, 0.6);
  overflow: hidden;
}
.qa > summary {
  cursor: pointer; padding: 13px 18px; list-style: none;
  font-size: 15.5px; color: var(--iron); font-weight: 600;
  display: flex; align-items: baseline; gap: 10px;
}
.qa > summary::-webkit-details-marker { display: none; }
.qa > summary::after {
  content: "点开对答案"; margin-left: auto; flex: none;
  font-family: var(--mono); font-size: 10px; letter-spacing: 0.1em;
  color: var(--iron-faint); font-weight: 400;
}
.qa[open] > summary::after { content: "收起"; }
.qa[open] > summary { border-bottom: 1px dashed var(--line); }
.qa > summary:hover { background: var(--purple-mist); }
.qa > summary .qn {
  font-family: var(--mono); font-size: 12px; color: var(--ember-deep);
  font-weight: 700; flex: none;
}
.qa .qbody { padding: 14px 18px 6px; font-size: 15.2px; line-height: 1.95; }
.qa .qbody pre { margin: 12px 0; }
.qa .qbody .hit {
  font-family: var(--mono); font-size: 11px; letter-spacing: 0.08em;
  color: var(--purple-deep); background: var(--purple-mist);
  border-radius: 5px; padding: 2px 9px; display: inline-block; margin-bottom: 8px;
}

/* ============ 翻页 ============ */
.pager {
  display: grid; grid-template-columns: 1fr 1fr; gap: 14px;
  margin: 56px 0 30px;
}
.pager a {
  border: 1px solid var(--line); border-radius: 10px;
  padding: 15px 18px; background: rgba(255, 255, 255, 0.6);
  display: block; color: var(--iron-body);
}
.pager a:hover { border-color: var(--purple); background: var(--purple-mist); }
.pager a .dir {
  font-family: var(--mono); font-size: 10.5px; letter-spacing: 0.16em;
  color: var(--iron-faint); display: block; margin-bottom: 5px;
}
.pager a .t { font-size: 14.5px; color: var(--iron); font-weight: 600; }
.pager a.next { text-align: right; }
.pager a.none { visibility: hidden; }
@media (max-width: 560px) { .pager { grid-template-columns: 1fr; } .pager a.next { text-align: left; } }

.foot {
  border-top: 1px solid var(--line);
  padding: 22px 0 46px; text-align: center;
  font-family: var(--mono); font-size: 11px; letter-spacing: 0.16em;
  color: var(--iron-faint);
}
.foot a { color: var(--purple-deep); border: none; }

/* ============ 总览页(index) ============ */
.hero { padding: 72px 0 30px; position: relative; }
.hero .surv {
  font-family: var(--mono); font-size: 11px; letter-spacing: 0.3em;
  color: var(--ember-deep); margin-bottom: 22px;
  display: flex; align-items: center; gap: 12px;
}
.hero .surv::after { content: ""; flex: 1; height: 1px; background: var(--line); }
.hero h1 {
  font-family: var(--serif); font-size: 74px; letter-spacing: 0.12em;
  color: var(--iron); font-weight: 700; line-height: 1.15; margin-bottom: 6px;
}
.hero h1 .molten {
  background: linear-gradient(135deg, var(--purple), var(--ember));
  -webkit-background-clip: text; background-clip: text;
  -webkit-text-fill-color: transparent; color: var(--ember);
}
.hero .en {
  font-family: var(--mono); font-size: 13px; letter-spacing: 0.5em;
  color: var(--iron-faint); margin-bottom: 30px;
}
.hero .pitch { font-size: 17.5px; line-height: 2.05; max-width: 640px; margin-bottom: 14px; }
.hero .pitch strong { color: var(--purple-deep); }
.hero-forge { margin: 36px 0 8px; }
.hero-forge svg { width: 100%; height: auto; display: block; }
.hero .meta-row { display: flex; gap: 10px; flex-wrap: wrap; margin-top: 24px; }
.hero .meta-row span {
  font-family: var(--mono); font-size: 11px; letter-spacing: 0.12em;
  color: var(--iron); background: rgba(255, 255, 255, 0.65);
  border: 1px solid var(--line); border-radius: 6px; padding: 5px 12px;
}
.hero .meta-row span b { color: var(--ember-deep); font-weight: 600; }
@media (max-width: 640px) { .hero h1 { font-size: 52px; } }

.station { margin: 46px 0 12px; position: relative; }
.station .st-kick {
  display: flex; align-items: center; gap: 12px; margin-bottom: 6px;
  font-family: var(--mono); font-size: 11px; letter-spacing: 0.22em; color: var(--purple-deep); font-weight: 700;
}
.station .st-kick .dot {
  width: 13px; height: 13px; border-radius: 50%; flex: none;
  background: var(--sand); border: 3px solid var(--purple);
}
.station .st-kick .bar {
  flex: 1; height: 3px; border-radius: 2px;
  background: linear-gradient(to right, rgba(127, 82, 255, 0.5), rgba(228, 72, 87, 0.08));
}
.station h2 { font-family: var(--serif); font-size: 27px; color: var(--iron); font-weight: 700; margin-bottom: 4px; }
.station .st-desc { font-size: 14.5px; color: var(--iron-faint); margin-bottom: 20px; }

.ch-list { display: grid; gap: 12px; margin-bottom: 14px; }
.ch-card {
  display: flex; gap: 16px; align-items: baseline;
  border: 1px solid var(--line); border-radius: 10px;
  background: rgba(255, 255, 255, 0.62);
  padding: 15px 18px; color: var(--iron-body);
  transition: transform 0.15s ease, background 0.15s ease, border-color 0.15s ease;
}
.ch-card:hover { border-color: var(--purple); background: var(--purple-mist); transform: translateX(4px); }
.ch-card .no {
  font-family: var(--mono); font-size: 13px; color: var(--ember-deep);
  font-weight: 600; min-width: 30px;
}
.ch-card .body { flex: 1; }
.ch-card .t { font-size: 16.5px; color: var(--iron); font-weight: 600; margin-bottom: 3px; display: block; }
.ch-card .d { font-size: 13.5px; color: var(--iron-faint); line-height: 1.75; display: block; }
.ch-card .demo-tag {
  font-family: var(--mono); font-size: 9.5px; letter-spacing: 0.08em;
  color: var(--ember-deep); border: 1px solid rgba(228, 72, 87, 0.4);
  border-radius: 4px; padding: 2px 7px; white-space: nowrap; align-self: center;
}

/* ============ 杂项 ============ */
.kbd {
  font-family: var(--mono); font-size: 0.82em;
  border: 1px solid var(--line); border-bottom-width: 2px;
  border-radius: 5px; padding: 0.05em 0.45em;
  background: #fff; color: var(--iron);
}
.small-cap { font-family: var(--mono); font-size: 11px; letter-spacing: 0.18em; color: var(--iron-faint); }

@media (max-width: 640px) {
  body { font-size: 15.5px; }
  .chapter-head h1 { font-size: 30px; }
  .prose h2 { font-size: 22px; }
  pre { font-size: 12.5px; padding: 14px 14px; }
}