/* ============================================================
   学习区共享样式表 · Learning workspace shared stylesheet
   所有课程与参考文档都应链接本文件：
     <link rel="stylesheet" href="../assets/course.css">
   目标：像同一门课，而不是一堆一次性页面；打印也好看。
   ============================================================ */

:root {
  --paper:      #fdfcf8;
  --ink:        #1b1a18;
  --ink-soft:   #5f5a53;
  --ink-faint:  #8d867c;
  --rule:       #e2ddd2;
  --accent:     #8c2f1e;   /* 朱红：标题装饰、强调 */
  --win:        #1f5c3a;   /* 绿：目标 / 答对 */
  --warn:       #9a6a08;   /* 黄：坑 / 注意 */
  --code-bg:    #f5f2ea;
  --code-key:   #8c2f1e;
  --code-str:   #2c5d7a;
}

* { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  padding: 3.5rem 1.5rem 6rem;
  background: var(--paper);
  color: var(--ink);
  font-family: "Songti SC", "Source Han Serif SC", "Noto Serif SC", Georgia, "Times New Roman", serif;
  font-size: 17px;
  line-height: 1.72;
  text-rendering: optimizeLegibility;
}

.page { max-width: 40rem; margin: 0 auto; }

/* ---------- 页眉 / 课程编号 ---------- */

.eyebrow {
  font-family: -apple-system, "Helvetica Neue", "PingFang SC", sans-serif;
  font-size: .72rem;
  letter-spacing: .18em;
  text-transform: uppercase;
  color: var(--ink-faint);
  margin: 0 0 .6rem;
}

h1 {
  font-size: 1.85rem;
  line-height: 1.25;
  font-weight: 600;
  margin: 0 0 .35rem;
  letter-spacing: -.01em;
}

h1 + .subtitle {
  font-size: 1rem;
  color: var(--ink-soft);
  font-style: italic;
  margin: 0 0 2.2rem;
}

h2 {
  font-size: 1.15rem;
  font-weight: 600;
  margin: 2.8rem 0 .9rem;
  padding-top: .9rem;
  border-top: 1px solid var(--rule);
}

h2::before {
  content: attr(data-step);
  display: inline-block;
  min-width: 1.6em;
  color: var(--accent);
  font-family: -apple-system, "Helvetica Neue", sans-serif;
  font-size: .8rem;
  letter-spacing: .05em;
  vertical-align: .12em;
}

h3 { font-size: 1rem; font-weight: 600; margin: 1.8rem 0 .5rem; }

p { margin: 0 0 1rem; }

a { color: var(--accent); text-decoration: none; border-bottom: 1px solid #d8c9c2; }
a:hover { border-bottom-color: var(--accent); }

strong { font-weight: 600; }

em { font-style: italic; color: var(--ink-soft); }

/* ---------- 目标框：每课一个“看得见的赢” ---------- */

.win {
  border-left: 3px solid var(--win);
  background: #f2f7f2;
  padding: 1rem 1.2rem;
  margin: 0 0 2rem;
  border-radius: 0 4px 4px 0;
}
.win .label {
  display: block;
  font-family: -apple-system, "Helvetica Neue", "PingFang SC", sans-serif;
  font-size: .7rem;
  letter-spacing: .16em;
  text-transform: uppercase;
  color: var(--win);
  margin-bottom: .35rem;
}
.win p:last-child { margin-bottom: 0; }

/* ---------- 提示块 ---------- */

.note, .pitfall {
  border-left: 3px solid var(--ink-faint);
  padding: .85rem 1.1rem;
  margin: 1.4rem 0;
  background: #f8f6f0;
  border-radius: 0 4px 4px 0;
  font-size: .96rem;
}
.pitfall { border-left-color: var(--warn); background: #fbf6e9; }
.note p:last-child, .pitfall p:last-child { margin-bottom: 0; }
.note .label, .pitfall .label {
  display: block;
  font-family: -apple-system, "Helvetica Neue", "PingFang SC", sans-serif;
  font-size: .7rem;
  letter-spacing: .14em;
  text-transform: uppercase;
  color: var(--warn);
  margin-bottom: .3rem;
}
.note .label { color: var(--ink-faint); }

/* ---------- 代码 ---------- */

code {
  font-family: "SF Mono", ui-monospace, Menlo, Consolas, monospace;
  font-size: .86em;
  background: var(--code-bg);
  padding: .12em .35em;
  border-radius: 3px;
}

pre {
  background: var(--code-bg);
  border: 1px solid var(--rule);
  border-radius: 4px;
  padding: 1rem 1.1rem;
  overflow-x: auto;
  font-size: .84rem;
  line-height: 1.62;
  margin: 1rem 0 1.4rem;
}
pre code { background: none; padding: 0; font-size: 1em; }

pre .c { color: var(--ink-faint); font-style: italic; }   /* 注释 */
pre .k { color: var(--code-key); }                        /* 关键字/函数 */
pre .s { color: var(--code-str); }                        /* 字符串 */

/* 终端提示符 */
.term { display: block; }
.term::before { content: "$ "; color: var(--win); }

/* ---------- 步骤 ---------- */

.steps { counter-reset: step; list-style: none; padding: 0; margin: 1.4rem 0; }
.steps > li {
  counter-increment: step;
  position: relative;
  padding-left: 2.4rem;
  margin-bottom: 1.6rem;
}
.steps > li::before {
  content: counter(step);
  position: absolute;
  left: 0; top: .1rem;
  width: 1.6rem; height: 1.6rem;
  border: 1px solid var(--accent);
  color: var(--accent);
  border-radius: 50%;
  font-family: -apple-system, "Helvetica Neue", sans-serif;
  font-size: .8rem;
  line-height: 1.5rem;
  text-align: center;
}
.steps > li > .step-title { font-weight: 600; display: block; margin-bottom: .2rem; }

/* ---------- 测验 ---------- */

.quiz {
  border: 1px solid var(--rule);
  border-radius: 5px;
  padding: 1.1rem 1.2rem;
  margin: 1.4rem 0;
  background: #fff;
}
.quiz .q { font-weight: 600; margin: 0 0 .8rem; }
.quiz .q::before {
  content: "Q" attr(data-n);
  color: var(--accent);
  font-family: -apple-system, "Helvetica Neue", sans-serif;
  font-size: .78rem;
  margin-right: .5em;
  letter-spacing: .06em;
}
.opt {
  display: block;
  width: 100%;
  text-align: left;
  font: inherit;
  font-size: .95rem;
  color: var(--ink);
  background: #faf8f3;
  border: 1px solid var(--rule);
  border-radius: 4px;
  padding: .55rem .8rem;
  margin: 0 0 .5rem;
  cursor: pointer;
  transition: background .12s, border-color .12s;
}
.opt:hover { background: #f3efe6; border-color: var(--ink-faint); }
.opt .key {
  display: inline-block;
  width: 1.4em;
  color: var(--ink-faint);
  font-family: -apple-system, "Helvetica Neue", sans-serif;
  font-size: .85em;
}
.opt.picked-ok { background: #eef7f0; border-color: var(--win); }
.opt.picked-ok .key { color: var(--win); }
.opt.picked-no { background: #fdf0ee; border-color: var(--accent); }
.opt.picked-no .key { color: var(--accent); }

.quiz .answer-row { display: flex; gap: .5rem; align-items: center; margin-top: .3rem; }
.quiz input[type="text"] {
  font: inherit;
  font-size: .95rem;
  padding: .5rem .7rem;
  border: 1px solid var(--rule);
  border-radius: 4px;
  background: #faf8f3;
  color: var(--ink);
  width: 8rem;
}
.quiz .check {
  font: inherit;
  font-size: .9rem;
  padding: .5rem 1rem;
  border: 1px solid var(--accent);
  color: var(--accent);
  background: transparent;
  border-radius: 4px;
  cursor: pointer;
}
.quiz .check:hover { background: var(--accent); color: #fff; }

.fb { font-size: .92rem; margin-top: .7rem; min-height: 1.2em; }
.fb.ok { color: var(--win); }
.fb.no { color: var(--accent); }

details {
  border-top: 1px solid var(--rule);
  padding: .7rem 0;
  margin: .6rem 0;
}
details summary {
  cursor: pointer;
  font-size: .92rem;
  color: var(--ink-soft);
  font-family: -apple-system, "Helvetica Neue", "PingFang SC", sans-serif;
}
details[open] summary { margin-bottom: .8rem; }

/* ---------- 页脚 ---------- */

.lesson-foot {
  margin-top: 3.5rem;
  padding-top: 1.2rem;
  border-top: 2px solid var(--ink);
  font-size: .92rem;
  color: var(--ink-soft);
}
.lesson-foot h2 { border: none; padding-top: 0; margin-top: 1.6rem; }
.lesson-foot ul { padding-left: 1.2rem; }
.lesson-foot li { margin-bottom: .4rem; }

.ask {
  margin: 2rem 0 0;
  padding: 1rem 1.2rem;
  background: #f6f2f8;
  border-left: 3px solid #6b4a7a;
  border-radius: 0 4px 4px 0;
  font-size: .96rem;
}
.ask p:last-child { margin-bottom: 0; }

.src {
  font-size: .84rem;
  color: var(--ink-faint);
  font-family: -apple-system, "Helvetica Neue", "PingFang SC", sans-serif;
  margin-top: -.9rem;
}

/* ---------- 参考文档专用 ---------- */

.gloss dt { font-weight: 600; margin-top: 1.2rem; }
.gloss dd { margin: .25rem 0 0 0; padding-left: 0; color: var(--ink); }
.gloss dd .en {
  font-family: "SF Mono", ui-monospace, Menlo, monospace;
  font-size: .84em;
  color: var(--accent);
}

table.sheet {
  width: 100%;
  border-collapse: collapse;
  font-size: .88rem;
  font-family: -apple-system, "Helvetica Neue", "PingFang SC", sans-serif;
  margin: 1rem 0 1.6rem;
}
table.sheet th, table.sheet td {
  border-bottom: 1px solid var(--rule);
  padding: .5rem .6rem;
  text-align: left;
  vertical-align: top;
}
table.sheet th { font-weight: 600; border-bottom-color: var(--ink-faint); }
table.sheet code { font-size: .95em; }

/* ---------- 打印 ---------- */

@media print {
  :root { --paper: #fff; }
  body { font-size: 10.5pt; padding: 0; }
  .page { max-width: none; }
  a { color: var(--ink); border: none; }
  .opt, .quiz .check { display: none; }
  .quiz { background: none; border: none; padding: 0; }
  .fb { display: none; }
  h2 { page-break-after: avoid; }
  pre { page-break-inside: avoid; }
}

@media (max-width: 480px) {
  body { padding: 2rem 1.1rem 4rem; font-size: 16px; }
  h1 { font-size: 1.5rem; }
  pre { font-size: .78rem; }
}

/* ---- 站点首页专用 ---- */
.topic { margin: 2.6rem 0; padding-top: 1.4rem; border-top: 1px solid var(--rule); }
.topic h2 { border: none; padding-top: 0; margin-top: 0; font-size: 1.35rem; }
.topic h2::before { content: ""; }
.topic h3 {
  font-family: -apple-system, "Helvetica Neue", "PingFang SC", sans-serif;
  font-size: .74rem; letter-spacing: .16em; text-transform: uppercase;
  color: var(--ink-faint); margin: 1.4rem 0 .6rem; font-weight: 600;
}
.path { font-size: .82rem; color: var(--ink-faint); margin: -.4rem 0 1rem; }
.doclist { list-style: none; padding: 0; margin: 0; }
.doclist li { padding: .5rem 0; border-bottom: 1px solid var(--rule); }
.doclist.plain li { color: var(--ink-soft); font-size: .93rem; }
.doclist .file {
  display: block;
  font-family: "SF Mono", ui-monospace, Menlo, monospace;
  font-size: .72rem; color: var(--ink-faint); margin-top: .18rem;
}
.empty { color: var(--ink-faint); font-style: italic; }
.site-foot {
  margin-top: 3rem; padding-top: 1rem; border-top: 2px solid var(--ink);
  font-size: .84rem; color: var(--ink-faint);
}