/* ============================================================================
   30 天全方位 Ruby 課程 — 網站樣式
   設計語言：排版優先（typography-first）、暖紙感淺色為預設、單一 Ruby 紅強調色、
   hairline 分隔線、大量留白、雜誌目錄式索引、程式碼如紙上印刷。
   全部色彩與字體以 CSS custom properties 管理；深色模式以 [data-theme="dark"] 切換。
   ========================================================================== */

/* ----------------------------------------------------------------------------
   1. 色彩與字體系統
   -------------------------------------------------------------------------- */
:root {
  /* 字體 */
  --font-serif: "Noto Serif TC", "Songti TC", "PMingLiU", serif;
  --font-sans: "Noto Sans TC", "PingFang TC", "Microsoft JhengHei",
               system-ui, -apple-system, sans-serif;
  --font-mono: "JetBrains Mono", "Cascadia Code", "Menlo", "Consolas",
               ui-monospace, SFMono-Regular, monospace;

  /* 淺色：暖紙感 */
  --bg: #FAF6F0;            /* 米白紙底 */
  --bg-raised: #FFFDF9;     /* 卡片、浮起面 */
  --bg-inset: #F2ECE2;      /* 內凹面（行內 code 底、淡色塊） */
  --bg-code: #F5F0E7;       /* 程式碼區塊：淺暖底 */
  --ink: #1C1917;           /* 墨色內文 */
  --ink-soft: #57534E;      /* 次要文字 */
  --ink-faint: #948D85;     /* 弱化文字 */
  --hairline: #E5DCCE;      /* 極細分隔線（低對比） */
  --hairline-strong: #D6CBB9;
  --accent: #9B1C31;        /* 降彩度 Ruby 紅 */
  --accent-ink: #7E1628;    /* 強調色 hover 深一階 */
  --accent-wash: rgba(155, 28, 49, 0.06);
  --shadow: 0 1px 2px rgba(58, 44, 30, 0.05), 0 4px 14px rgba(58, 44, 30, 0.05);

  /* 狀態色（降彩度，與紙感一致） */
  --ok: #2F6B4F;
  --ok-wash: rgba(47, 107, 79, 0.08);
  --warn: #8A6D1F;
  --warn-wash: rgba(138, 109, 31, 0.08);
  --err: #A33A3A;
  --err-wash: rgba(163, 58, 58, 0.07);
  --info: #3A5A80;
  --info-wash: rgba(58, 90, 128, 0.07);

  /* 程式碼 token（hljs 與 CodeMirror 共用）：像紙上的多色印刷 */
  --code-keyword: #9B1C31;
  --code-string: #2F6B4F;
  --code-number: #8A4F1F;
  --code-comment: #999084;
  --code-def: #1F4E79;
  --code-atom: #6D4A9E;
  --code-builtin: #1F4E79;
  --code-variable: #1C1917;
  --code-regexp: #8A6D1F;
}

[data-theme="dark"] {
  /* 深色：暖深灰（非純黑） */
  --bg: #14110F;
  --bg-raised: #1C1815;
  --bg-inset: #241F1B;
  --bg-code: #1F1B17;
  --ink: #E8E1D7;
  --ink-soft: #ABA396;
  --ink-faint: #756D63;
  --hairline: #2C2722;
  --hairline-strong: #3A332C;
  --accent: #D97A8A;        /* 深底上的 Ruby 紅需要更亮的墨 */
  --accent-ink: #E69AA7;
  --accent-wash: rgba(217, 122, 138, 0.10);
  --shadow: 0 1px 2px rgba(0, 0, 0, 0.35), 0 4px 14px rgba(0, 0, 0, 0.25);

  --ok: #84B89C;
  --ok-wash: rgba(132, 184, 156, 0.10);
  --warn: #CBAA5C;
  --warn-wash: rgba(203, 170, 92, 0.10);
  --err: #DD8B8B;
  --err-wash: rgba(221, 139, 139, 0.09);
  --info: #8DAFD0;
  --info-wash: rgba(141, 175, 208, 0.09);

  --code-keyword: #DD8B98;
  --code-string: #93C2A5;
  --code-number: #D5A06A;
  --code-comment: #6F675D;
  --code-def: #8FB0D8;
  --code-atom: #B79BD9;
  --code-builtin: #8FB0D8;
  --code-variable: #E8E1D7;
  --code-regexp: #CBAA5C;
}

/* ----------------------------------------------------------------------------
   2. 基礎排版
   -------------------------------------------------------------------------- */
* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--font-sans);
  font-size: 17px;
  line-height: 1.8;                 /* 中文行高 */
  word-break: keep-all;             /* 中文不在詞中折行 */
  overflow-wrap: break-word;
  -webkit-font-smoothing: antialiased;
  transition: background-color 0.2s ease, color 0.2s ease;
}

h1, h2, h3, h4 {
  font-family: var(--font-serif);   /* 標題用思源宋體 */
  font-weight: 700;
  line-height: 1.5;
  color: var(--ink);
}

a { color: var(--accent); text-decoration: none; transition: color 0.15s ease; }
a:hover { color: var(--accent-ink); text-decoration: underline; text-underline-offset: 0.2em; }

code, pre, kbd, .mono { font-family: var(--font-mono); }

::selection { background: var(--accent-wash); }

.container { max-width: 72rem; margin: 0 auto; padding: 0 1.4rem; }
.dim { color: var(--ink-faint); }

.overline {
  font-family: var(--font-mono);
  font-size: 0.74rem;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--accent);
  margin: 0 0 0.4rem;
}

/* 內容淡入（內容區切換時加 .fade-in） */
@keyframes fade-in {
  from { opacity: 0; transform: translateY(4px); }
  to   { opacity: 1; transform: none; }
}
.fade-in { animation: fade-in 0.2s ease both; }

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { animation-duration: 0.01ms !important; transition-duration: 0.01ms !important; }
  html { scroll-behavior: auto; }
}

/* ----------------------------------------------------------------------------
   3. 按鈕
   -------------------------------------------------------------------------- */
button {
  font-family: var(--font-sans);
  font-size: 0.88rem;
  color: var(--ink);
  background: var(--bg-raised);
  border: 1px solid var(--hairline-strong);
  border-radius: 8px;
  padding: 0.42rem 0.95rem;
  cursor: pointer;
  transition: background-color 0.15s ease, border-color 0.15s ease,
              color 0.15s ease, box-shadow 0.15s ease;
}
button:hover:not(:disabled) { border-color: var(--accent); color: var(--accent); }
button:focus-visible, a:focus-visible, input:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}
button:disabled { opacity: 0.45; cursor: not-allowed; }

.primary-btn, button.primary {
  background: var(--accent);
  border-color: var(--accent);
  color: #FCF9F4;
}
.primary-btn:hover:not(:disabled), button.primary:hover:not(:disabled) {
  background: var(--accent-ink);
  border-color: var(--accent-ink);
  color: #FCF9F4;
}
[data-theme="dark"] .primary-btn, [data-theme="dark"] button.primary {
  color: #1A0D10;
}
[data-theme="dark"] .primary-btn:hover:not(:disabled),
[data-theme="dark"] button.primary:hover:not(:disabled) { color: #1A0D10; }

.ghost-btn { background: transparent; }

.icon-btn {
  background: transparent;
  border: 1px solid transparent;
  font-size: 1.05rem;
  line-height: 1;
  padding: 0.35rem 0.55rem;
  border-radius: 8px;
  color: var(--ink-soft);
}
.icon-btn:hover:not(:disabled) { border-color: var(--hairline-strong); color: var(--ink); }

/* ----------------------------------------------------------------------------
   4. 閱讀進度條 / 頂欄 / 回到頂部
   -------------------------------------------------------------------------- */
.reading-progress {
  position: fixed;
  top: 0; left: 0; right: 0;
  height: 2px;
  z-index: 200;
  background: transparent;
  pointer-events: none;
}
.reading-progress-fill {
  height: 100%;
  width: 0;
  background: var(--accent);
  transition: width 0.1s linear;
}

.topbar {
  position: sticky;
  top: 0;
  z-index: 100;
  display: flex;
  align-items: center;
  gap: 1.1rem;
  padding: 0.65rem 1.4rem;
  background: var(--bg);
  border-bottom: 1px solid var(--hairline);
}
.brand {
  font-family: var(--font-serif);
  font-weight: 700;
  font-size: 1.02rem;
  color: var(--ink);
  white-space: nowrap;
}
.brand:hover { color: var(--accent); text-decoration: none; }
.topnav { display: flex; gap: 1rem; }
.topnav a {
  font-size: 0.9rem;
  color: var(--ink-soft);
  padding: 0.15rem 0;
  border-bottom: 1px solid transparent;
  transition: color 0.15s ease, border-color 0.15s ease;
}
.topnav a:hover { color: var(--ink); text-decoration: none; }
.topnav a[aria-current="page"] { color: var(--accent); border-bottom-color: var(--accent); }
.topbar-spacer { flex: 1; }

.vm-status {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--ink-faint);
  border: 1px solid var(--hairline);
  border-radius: 999px;
  padding: 0.18rem 0.7rem;
  max-width: 21rem;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}
.vm-status[data-state="ready"]   { color: var(--ok); border-color: var(--ok); }
.vm-status[data-state="loading"] { color: var(--warn); border-color: var(--warn); }
.vm-status[data-state="running"] { color: var(--info); border-color: var(--info); }
.vm-status[data-state="error"]   { color: var(--err); border-color: var(--err); }

.back-to-top {
  position: fixed;
  right: 1.3rem;
  bottom: 5.2rem;
  z-index: 90;
  width: 2.6rem;
  height: 2.6rem;
  padding: 0;
  border-radius: 999px;
  border: 1px solid var(--hairline-strong);
  background: var(--bg-raised);
  color: var(--ink-soft);
  box-shadow: var(--shadow);
  opacity: 0;
  visibility: hidden;
  transform: translateY(6px);
  transition: opacity 0.18s ease, transform 0.18s ease, visibility 0.18s;
}
.back-to-top.visible { opacity: 1; visibility: visible; transform: none; }
.back-to-top:hover { color: var(--accent); border-color: var(--accent); }

.site-footer {
  border-top: 1px solid var(--hairline);
  margin-top: 5rem;
  padding: 2rem 1.4rem 3rem;
  text-align: center;
  color: var(--ink-faint);
  font-size: 0.85rem;
}

/* ----------------------------------------------------------------------------
   5. 首頁：雜誌目錄式 30 天索引
   -------------------------------------------------------------------------- */
.home-main { max-width: 46rem; padding-top: 3.5rem; }

.hero { margin-bottom: 3.5rem; }
.hero-title {
  font-size: 2.3rem;
  font-weight: 900;
  letter-spacing: 0.01em;
  margin: 0 0 0.9rem;
}
.hero-sub {
  color: var(--ink-soft);
  max-width: 38em;
  margin: 0 0 2rem;
}

.course-progress { max-width: 30rem; }
.progress-track {
  height: 4px;
  background: var(--bg-inset);
  border-radius: 999px;
  overflow: hidden;
}
.progress-bar-fill {
  height: 100%;
  width: 0;
  background: var(--accent);
  border-radius: 999px;
  transition: width 0.4s ease;
}
.progress-label {
  font-size: 0.82rem;
  color: var(--ink-faint);
  margin: 0.5rem 0 0;
}

.toc-section { margin-bottom: 3.2rem; }
.toc-head {
  display: flex;
  align-items: baseline;
  gap: 0.9rem;
  border-bottom: 1px solid var(--hairline-strong);
  padding-bottom: 0.6rem;
  margin-bottom: 0.2rem;
}
.toc-week {
  font-family: var(--font-mono);
  font-size: 0.74rem;
  letter-spacing: 0.18em;
  color: var(--accent);
}
.toc-head h2 {
  font-size: 1.3rem;
  margin: 0;
}

.toc-list { list-style: none; margin: 0; padding: 0; }
.toc-row {
  display: flex;
  align-items: flex-start;
  gap: 1rem;
  padding: 1.05rem 0.2rem;
  border-bottom: 1px solid var(--hairline);
  transition: background-color 0.15s ease;
}
.toc-row:hover { background: var(--accent-wash); }
.toc-row.unbuilt { opacity: 0.55; }

.toc-num {
  font-family: var(--font-serif);   /* 大號襯線數字：雜誌目錄感 */
  font-weight: 900;
  font-size: 1.75rem;
  line-height: 1.15;
  min-width: 2.6rem;
  text-align: right;
  color: var(--ink);
  font-variant-numeric: lining-nums;
}
.toc-row.done .toc-num { color: var(--ink-faint); }

.toc-main { flex: 1; min-width: 0; padding-top: 0.12rem; }
.toc-title {
  font-family: var(--font-serif);
  font-weight: 700;
  font-size: 1.06rem;
  color: var(--ink);
}
.toc-title:hover { color: var(--accent); text-decoration: none; }
.toc-row.done .toc-title { color: var(--ink-faint); }
span.toc-title { cursor: default; }

.toc-meta {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  flex-wrap: wrap;
  margin: 0.3rem 0 0;
  font-size: 0.8rem;
  color: var(--ink-faint);
}

.badge {
  display: inline-block;
  font-size: 0.72rem;
  line-height: 1.6;
  border: 1px solid var(--hairline-strong);
  border-radius: 999px;
  padding: 0 0.6rem;
  color: var(--ink-soft);
  white-space: nowrap;
}
.badge.project  { color: var(--info); border-color: var(--info); }
.badge.capstone { color: var(--accent); border-color: var(--accent); }
.badge.unbuilt  { border-style: dashed; }

/* 完成勾選 */
.done-toggle {
  appearance: none;
  width: 1.15rem;
  height: 1.15rem;
  margin: 0.45rem 0 0;
  border: 1.5px solid var(--hairline-strong);
  border-radius: 6px;
  background: var(--bg-raised);
  cursor: pointer;
  position: relative;
  flex-shrink: 0;
  transition: background-color 0.15s ease, border-color 0.15s ease;
}
.done-toggle:hover { border-color: var(--ok); }
.done-toggle:checked { background: var(--ok); border-color: var(--ok); }
.done-toggle:checked::after {
  content: "✓";
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--bg);
  font-size: 0.8rem;
  font-weight: 700;
}

/* ----------------------------------------------------------------------------
   6. 課程頁版型：側欄 + 主欄
   -------------------------------------------------------------------------- */
.lesson-layout { display: flex; min-height: calc(100vh - 3.4rem); }

.sidebar {
  width: 17rem;
  flex-shrink: 0;
  border-right: 1px solid var(--hairline);
  padding: 1rem 0.7rem 5rem;
  overflow-y: auto;
  position: sticky;
  top: 3.4rem;
  max-height: calc(100vh - 3.4rem);
  background: var(--bg);
}
.sidebar details { margin-bottom: 0.35rem; }
.sidebar summary {
  cursor: pointer;
  list-style: none;
  font-family: var(--font-serif);
  font-weight: 700;
  font-size: 0.86rem;
  color: var(--ink-soft);
  padding: 0.4rem 0.6rem;
  border-radius: 7px;
  user-select: none;
  transition: background-color 0.15s ease, color 0.15s ease;
}
.sidebar summary::-webkit-details-marker { display: none; }
.sidebar summary::before {
  content: "›";
  display: inline-block;
  margin-right: 0.45rem;
  color: var(--ink-faint);
  transition: transform 0.15s ease;
}
.sidebar details[open] > summary::before { transform: rotate(90deg); }
.sidebar summary:hover { background: var(--bg-inset); color: var(--ink); }

.nav-day {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.3rem 0.6rem 0.3rem 1.3rem;
  border-radius: 7px;
  font-size: 0.85rem;
  color: var(--ink-soft);
  transition: background-color 0.15s ease, color 0.15s ease;
}
.nav-day:hover { background: var(--bg-inset); color: var(--ink); text-decoration: none; }
.nav-day.current {
  background: var(--accent-wash);
  color: var(--accent);
  font-weight: 500;
}
.nav-day.unbuilt { opacity: 0.45; pointer-events: none; }
.nav-day .num {
  font-family: var(--font-serif);
  font-weight: 700;
  min-width: 1.5rem;
  font-variant-numeric: lining-nums;
}
.nav-day .label {
  flex: 1;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}
.nav-day .check { color: var(--ok); font-size: 0.8rem; }

.sidebar-toggle { display: none; }
.sidebar-backdrop { display: none; }

.lesson-main {
  flex: 1;
  min-width: 0;
  padding: 2.6rem 2.4rem 9rem;
}
/* 閱讀欄寬上限約 70ch、置中 */
.lesson-main > * { max-width: 70ch; margin-left: auto; margin-right: auto; }

.lesson-header { margin-bottom: 1.6rem; }
.lesson-info {
  font-size: 0.82rem;
  color: var(--ink-faint);
  margin: 0 0 0.5rem;
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.65rem;
}
.lesson-info .sep { color: var(--hairline-strong); }
.lesson-info .day-label {
  font-family: var(--font-serif);
  font-weight: 700;
  color: var(--accent);
  font-size: 0.9rem;
}
.lesson-title-row {
  display: flex;
  align-items: flex-start;
  gap: 1rem;
  flex-wrap: wrap;
}
.lesson-title {
  font-size: 1.75rem;
  font-weight: 900;
  margin: 0;
  flex: 1;
  min-width: 14rem;
}
#mark-done.done { color: var(--ok); border-color: var(--ok); }

/* 橫幅 */
.banner {
  border: 1px solid var(--warn);
  border-left-width: 3px;
  background: var(--warn-wash);
  color: var(--ink);
  border-radius: 8px;
  padding: 0.75rem 1.05rem;
  margin: 0 auto 1rem;
  font-size: 0.92rem;
}
.banner.info { border-color: var(--info); background: var(--info-wash); }
.banner.error { border-color: var(--err); background: var(--err-wash); }
.banner code {
  background: var(--bg-inset);
  border-radius: 5px;
  padding: 0.08rem 0.4rem;
  font-size: 0.85em;
}
.banner .banner-title { font-weight: 700; }

/* 分頁 tabs */
.tabs {
  display: flex;
  gap: 0.2rem;
  border-bottom: 1px solid var(--hairline);
  margin: 1.6rem auto 1.8rem;
}
.tabs:empty { display: none; }
.tabs button {
  background: none;
  border: none;
  border-bottom: 2px solid transparent;
  border-radius: 0;
  color: var(--ink-soft);
  padding: 0.5rem 1rem;
  font-size: 0.95rem;
  margin-bottom: -1px;
}
.tabs button:hover:not(:disabled) { color: var(--ink); }
.tabs button.active {
  color: var(--accent);
  border-bottom-color: var(--accent);
  font-weight: 500;
}
.tab-panel { display: none; }
.tab-panel.active { display: block; }

/* 上一天 / 下一天 */
.pager {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.9rem;
  margin-top: 4rem;
  padding-top: 1.6rem;
  border-top: 1px solid var(--hairline);
}
.pager a, .pager span.pager-empty {
  display: block;
  border: 1px solid var(--hairline);
  border-radius: 9px;
  padding: 0.8rem 1.05rem;
  color: var(--ink);
  transition: border-color 0.15s ease, background-color 0.15s ease;
}
.pager a:hover {
  border-color: var(--accent);
  background: var(--accent-wash);
  text-decoration: none;
}
.pager .pager-dir {
  display: block;
  font-size: 0.76rem;
  color: var(--ink-faint);
  margin-bottom: 0.2rem;
}
.pager .pager-title {
  font-family: var(--font-serif);
  font-weight: 700;
  font-size: 0.95rem;
}
.pager .next { text-align: right; }
.pager span.pager-empty { opacity: 0.5; border-style: dashed; }

/* ----------------------------------------------------------------------------
   7. 講義（Markdown）排版：閱讀為先
   -------------------------------------------------------------------------- */
.prose { font-size: 1rem; }
.prose > :first-child { margin-top: 0; }
.prose h1 { font-size: 1.5rem; margin: 2.4rem 0 1rem; }
.prose h2 {
  font-size: 1.28rem;
  margin: 2.6rem 0 1rem;
  padding-bottom: 0.45rem;
  border-bottom: 1px solid var(--hairline);
}
.prose h3 { font-size: 1.1rem; margin: 2rem 0 0.8rem; }
.prose p { margin: 0.9rem 0; }
.prose ul, .prose ol { padding-left: 1.6rem; margin: 0.9rem 0; }
.prose li { margin: 0.3rem 0; }
.prose hr { border: none; border-top: 1px solid var(--hairline); margin: 2.4rem 0; }
.prose img { max-width: 100%; border-radius: 8px; }

.prose blockquote {
  border-left: 2px solid var(--accent);   /* 左側細紅線 */
  margin: 1.3rem 0;
  padding: 0.1rem 0 0.1rem 1.1rem;
  color: var(--ink-soft);
}

.prose table {
  border-collapse: collapse;
  margin: 1.3rem 0;
  display: block;
  overflow-x: auto;
  font-size: 0.92rem;
}
.prose th, .prose td {
  border: 1px solid var(--hairline);
  padding: 0.45rem 0.8rem;
  text-align: left;
}
.prose th {
  font-family: var(--font-serif);
  font-weight: 700;
  background: var(--bg-inset);
}

/* 行內 code：淡底 + 強調色文字 */
.prose :not(pre) > code, .toc-meta code, li code {
  background: var(--bg-inset);
  color: var(--accent);
  border-radius: 5px;
  padding: 0.1rem 0.4rem;
  font-size: 0.85em;
}

/* 程式碼區塊：像紙上印刷 */
.prose pre, pre.code-print {
  background: var(--bg-code);
  border: 1px solid var(--hairline);
  border-radius: 9px;
  padding: 1rem 1.15rem;
  overflow-x: auto;
  font-size: 0.84rem;
  line-height: 1.65;
  margin: 1.2rem 0;
}
.prose pre code, pre.code-print code {
  background: none;
  color: var(--ink);
  padding: 0;
  font-size: inherit;
}

/* highlight.js token 配色（覆蓋為與整體一致的印刷感） */
.hljs { background: transparent; color: var(--ink); }
.hljs-comment, .hljs-quote { color: var(--code-comment); font-style: italic; }
.hljs-keyword, .hljs-selector-tag, .hljs-literal, .hljs-doctag { color: var(--code-keyword); }
.hljs-string, .hljs-addition { color: var(--code-string); }
.hljs-number, .hljs-deletion { color: var(--code-number); }
.hljs-symbol, .hljs-bullet, .hljs-link, .hljs-attr, .hljs-attribute { color: var(--code-atom); }
.hljs-title, .hljs-title.class_, .hljs-title.function_, .hljs-section, .hljs-name { color: var(--code-def); }
.hljs-built_in, .hljs-type, .hljs-class { color: var(--code-builtin); }
.hljs-variable, .hljs-template-variable, .hljs-params { color: var(--code-variable); }
.hljs-regexp, .hljs-meta { color: var(--code-regexp); }
.hljs-subst { color: var(--ink); }
.hljs-emphasis { font-style: italic; }
.hljs-strong { font-weight: 600; }

/* 講義裡的 ruby code block：右上角執行按鈕 */
.runnable-block { position: relative; }
.runnable-block .run-snippet-btn {
  position: absolute;
  top: 0.5rem;
  right: 0.5rem;
  font-size: 0.74rem;
  padding: 0.18rem 0.6rem;
  border-radius: 6px;
  background: var(--bg-raised);
  border: 1px solid var(--hairline-strong);
  color: var(--ink-soft);
  opacity: 0;
  transition: opacity 0.15s ease, color 0.15s ease, border-color 0.15s ease;
}
.runnable-block:hover .run-snippet-btn,
.runnable-block .run-snippet-btn:focus-visible { opacity: 1; }
.runnable-block .run-snippet-btn:hover { color: var(--accent); border-color: var(--accent); }
@media (hover: none) {
  .runnable-block .run-snippet-btn { opacity: 1; }
}

/* ----------------------------------------------------------------------------
   8. 範例卡 / 練習卡
   -------------------------------------------------------------------------- */
.card {
  background: var(--bg-raised);
  border: 1px solid var(--hairline);
  border-radius: 10px;
  box-shadow: var(--shadow);
  padding: 1.15rem 1.25rem 1.25rem;
  margin: 0 auto 1.4rem;
  transition: border-color 0.15s ease;
}
.card:hover { border-color: var(--hairline-strong); }

.card-head {
  display: flex;
  align-items: baseline;
  gap: 0.7rem;
  flex-wrap: wrap;
  margin-bottom: 0.6rem;
}
.card-head .ex-num {
  font-family: var(--font-serif);
  font-weight: 900;
  font-size: 1.3rem;
  color: var(--accent);
  line-height: 1;
}
.card-head .name {
  font-family: var(--font-mono);
  font-weight: 600;
  font-size: 0.95rem;
}
.card-head .file-path {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--ink-faint);
}
.card .btn-row {
  display: flex;
  gap: 0.5rem;
  flex-wrap: wrap;
  align-items: center;
  margin: 0.8rem 0 0.2rem;
}

.example-pre { max-height: 24rem; overflow: auto; margin: 0.5rem 0; }

.pane-label {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--ink-faint);
  margin: 0 0 0.4rem;
}

/* CodeMirror：紙感淺底（沿用 default theme、以變數覆蓋配色） */
.CodeMirror {
  height: auto;
  min-height: 7rem;
  border: 1px solid var(--hairline);
  border-radius: 9px;
  background: var(--bg-code);
  color: var(--ink);
  font-family: var(--font-mono);
  font-size: 0.84rem;
  line-height: 1.65;
  transition: border-color 0.15s ease;
}
.CodeMirror-focused { border-color: var(--hairline-strong); }
.CodeMirror-scroll { max-height: 30rem; }
.CodeMirror-gutters {
  background: var(--bg-code);
  border-right: 1px solid var(--hairline);
}
.CodeMirror-linenumber { color: var(--ink-faint); }
.CodeMirror-cursor { border-left: 2px solid var(--accent); }
.CodeMirror-selected { background: var(--accent-wash) !important; }
.CodeMirror pre.CodeMirror-line { word-break: normal; }
.cm-s-default .cm-keyword  { color: var(--code-keyword); }
.cm-s-default .cm-string,
.cm-s-default .cm-string-2 { color: var(--code-string); }
.cm-s-default .cm-number   { color: var(--code-number); }
.cm-s-default .cm-comment  { color: var(--code-comment); font-style: italic; }
.cm-s-default .cm-def      { color: var(--code-def); }
.cm-s-default .cm-atom     { color: var(--code-atom); }
.cm-s-default .cm-builtin,
.cm-s-default .cm-tag      { color: var(--code-builtin); }
.cm-s-default .cm-variable,
.cm-s-default .cm-variable-2,
.cm-s-default .cm-variable-3,
.cm-s-default .cm-property,
.cm-s-default .cm-operator { color: var(--code-variable); }
.cm-s-default .cm-meta     { color: var(--code-regexp); }
.CodeMirror[data-readonly="true"] { opacity: 0.92; }

/* 測試結果：紅綠清單 */
.test-results { margin-top: 1rem; }
.test-summary {
  font-family: var(--font-mono);
  font-size: 0.84rem;
  padding: 0.5rem 0.85rem;
  border-radius: 7px;
  border: 1px solid var(--hairline);
  margin-bottom: 0.55rem;
}
.test-summary.green { color: var(--ok); border-color: var(--ok); background: var(--ok-wash); }
.test-summary.red   { color: var(--err); border-color: var(--err); background: var(--err-wash); }

.test-row {
  border: 1px solid var(--hairline);
  border-radius: 7px;
  margin-bottom: 0.3rem;
  font-size: 0.83rem;
  overflow: hidden;
  background: var(--bg-raised);
}
.test-row summary {
  padding: 0.38rem 0.75rem;
  cursor: pointer;
  font-family: var(--font-mono);
  display: flex;
  gap: 0.55rem;
  align-items: baseline;
  user-select: none;
  list-style: none;
}
.test-row summary::-webkit-details-marker { display: none; }
.test-row.pass summary { color: var(--ok); cursor: default; }
.test-row.fail summary { color: var(--err); }
.test-row.error summary { color: var(--warn); }
.test-row.skip summary { color: var(--ink-faint); }
.test-row .detail {
  padding: 0.55rem 0.95rem 0.75rem;
  border-top: 1px solid var(--hairline);
  white-space: pre-wrap;
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--ink-soft);
  overflow-x: auto;
  background: var(--bg-code);
}

.solution-view { margin-top: 1rem; }
.solution-view .pane-label { margin-top: 0.6rem; }

/* ----------------------------------------------------------------------------
   9. 輸出窗 / Playground / 抽屜
   -------------------------------------------------------------------------- */
.output-pane {
  background: var(--bg-code);
  border: 1px solid var(--hairline);
  border-radius: 9px;
  padding: 0.85rem 1.05rem;
  font-family: var(--font-mono);
  font-size: 0.84rem;
  line-height: 1.6;
  white-space: pre-wrap;
  word-break: break-word;
  min-height: 3.2rem;
  max-height: 24rem;
  overflow: auto;
}
.output-pane .result-line { color: var(--ok); }
.output-pane .error-block { color: var(--err); }
.output-pane .dim { color: var(--ink-faint); }

.pg-main { max-width: 76rem; padding-top: 2.6rem; padding-bottom: 7rem; }
.pg-header { margin-bottom: 1.8rem; }
.pg-title { font-size: 1.9rem; font-weight: 900; margin: 0 0 0.6rem; }
.pg-sub { color: var(--ink-soft); max-width: 44em; margin: 0; }

.pg-toolbar {
  display: flex;
  gap: 0.55rem;
  flex-wrap: wrap;
  align-items: center;
  margin-bottom: 1rem;
}
.pg-note { font-size: 0.82rem; color: var(--ink-faint); }

.pg-grid {
  display: grid;
  grid-template-columns: 1.25fr 1fr;
  gap: 1.1rem;
  align-items: start;
}
.pg-grid .CodeMirror-scroll { max-height: 62vh; }
.pg-grid .output-pane { max-height: 62vh; }

/* 課程頁底部 Playground 抽屜 */
.drawer {
  position: fixed;
  left: 0; right: 0; bottom: 0;
  background: var(--bg-raised);
  border-top: 1px solid var(--hairline-strong);
  box-shadow: 0 -6px 24px rgba(58, 44, 30, 0.12);
  transform: translateY(100%);
  transition: transform 0.2s ease;
  z-index: 110;
  max-height: 72vh;
  display: flex;
  flex-direction: column;
}
[data-theme="dark"] .drawer { box-shadow: 0 -6px 24px rgba(0, 0, 0, 0.45); }
.drawer.open { transform: translateY(0); }
.drawer-head {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  padding: 0.55rem 1.1rem;
  border-bottom: 1px solid var(--hairline);
  flex-wrap: wrap;
}
.drawer-head .title {
  font-family: var(--font-serif);
  font-weight: 700;
  font-size: 0.95rem;
  color: var(--accent);
}
.drawer-head .pg-hint { font-size: 0.78rem; color: var(--ink-faint); }
.drawer-body {
  display: grid;
  grid-template-columns: 1.2fr 1fr;
  gap: 0.9rem;
  padding: 0.9rem 1.1rem 1.1rem;
  overflow: auto;
}
.drawer-body .CodeMirror-scroll { max-height: 44vh; }

.drawer-open-fab {
  position: fixed;
  right: 1.3rem;
  bottom: 1.4rem;
  z-index: 95;
  border-radius: 999px;
  padding: 0.6rem 1.15rem;
  background: var(--accent);
  border: 1px solid var(--accent);
  color: #FCF9F4;
  font-weight: 500;
  font-size: 0.88rem;
  box-shadow: var(--shadow);
  transition: background-color 0.15s ease, transform 0.15s ease;
}
.drawer-open-fab:hover:not(:disabled) { background: var(--accent-ink); border-color: var(--accent-ink); color: #FCF9F4; }
[data-theme="dark"] .drawer-open-fab { color: #1A0D10; }
[data-theme="dark"] .drawer-open-fab:hover:not(:disabled) { color: #1A0D10; }

.loading-note {
  border: 1px dashed var(--hairline-strong);
  border-radius: 8px;
  color: var(--ink-faint);
  padding: 0.6rem 1rem;
  font-size: 0.86rem;
  margin: 0.6rem 0;
}

/* ----------------------------------------------------------------------------
   10. 響應式（行動裝置單欄）
   -------------------------------------------------------------------------- */
@media (max-width: 960px) {
  body { font-size: 16.5px; }

  .topbar { padding: 0.55rem 0.9rem; gap: 0.7rem; }
  .vm-status { max-width: 9rem; }

  .sidebar {
    position: fixed;
    left: 0;
    top: 3.4rem;
    bottom: 0;
    z-index: 120;
    width: 17rem;
    max-height: none;
    background: var(--bg);
    transform: translateX(-105%);
    transition: transform 0.2s ease;
    box-shadow: var(--shadow);
  }
  .sidebar.open { transform: translateX(0); }
  .sidebar-toggle { display: inline-block; }
  .sidebar-backdrop.show {
    display: block;
    position: fixed;
    inset: 3.4rem 0 0 0;
    z-index: 115;
    background: rgba(28, 25, 23, 0.28);
  }

  .lesson-main { padding: 1.6rem 1.1rem 8rem; }
  .pager { grid-template-columns: 1fr; }
  .pg-grid, .drawer-body { grid-template-columns: 1fr; }
  .hero-title { font-size: 1.8rem; }
  .home-main { padding-top: 2.2rem; }
  .toc-num { font-size: 1.45rem; min-width: 2.2rem; }
}