/* ==========================================================================
   CrowdStrike on GCP — 互動式學習網站
   styles.css — 原生 CSS，無框架相依
   ========================================================================== */

/* ---------- 1. 設計權杖 (Design Tokens) ---------- */

:root {
  color-scheme: light;

  /* 中性色階 */
  --c-bg:            #f7f8fa;
  --c-surface:       #ffffff;
  --c-surface-2:     #f0f2f5;
  --c-surface-3:     #e4e7ec;
  --c-border:        #d8dce3;
  --c-border-soft:   #e8ebf0;

  /* 文字 */
  --c-text:          #14171f;
  --c-text-2:        #4a5160;
  --c-text-3:        #767e8f;

  /* 品牌 / 強調 */
  --c-accent:        #c8102e;   /* CrowdStrike 紅（僅作為視覺辨識，非官方色票） */
  --c-accent-soft:   #fdeaed;
  --c-accent-text:   #9c0c24;
  --c-gcp:           #1a73e8;   /* Google Cloud 藍（僅作視覺辨識） */
  --c-gcp-soft:      #e8f0fe;
  --c-gcp-text:      #1558b8;

  /* 語意色 */
  --c-ok:            #1a7f45;
  --c-ok-soft:       #e6f4ec;
  --c-ok-text:       #116336;
  --c-warn:          #b7791f;
  --c-warn-soft:     #fdf3e0;
  --c-warn-text:     #8a5a12;
  --c-danger:        #c0392b;
  --c-danger-soft:   #fdecea;
  --c-danger-text:   #922b21;
  --c-info:          #4a5fc1;
  --c-info-soft:     #eceffb;
  --c-info-text:     #35479a;

  /* 排版 */
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "Noto Sans TC",
               "PingFang TC", "Microsoft JhengHei", "Helvetica Neue", Arial, sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas,
               "Liberation Mono", monospace;

  /* 尺寸 */
  --sidebar-w: 288px;
  --topbar-h: 60px;
  --content-max: 900px;
  --radius: 8px;
  --radius-sm: 5px;
  --radius-lg: 14px;

  /* 陰影 */
  --shadow-sm: 0 1px 2px rgba(16, 20, 30, .06), 0 1px 3px rgba(16, 20, 30, .04);
  --shadow-md: 0 4px 12px rgba(16, 20, 30, .08), 0 1px 3px rgba(16, 20, 30, .05);
  --shadow-lg: 0 12px 32px rgba(16, 20, 30, .14);

  --transition: 160ms cubic-bezier(.4, 0, .2, 1);
}

:root[data-theme="dark"] {
  color-scheme: dark;

  --c-bg:            #0e1116;
  --c-surface:       #161b22;
  --c-surface-2:     #1c232c;
  --c-surface-3:     #262d38;
  --c-border:        #303845;
  --c-border-soft:   #232a34;

  --c-text:          #e6e9ef;
  --c-text-2:        #a8b1c0;
  --c-text-3:        #7b8494;

  --c-accent:        #ff5c72;
  --c-accent-soft:   #33161c;
  --c-accent-text:   #ff8b9b;
  --c-gcp:           #5b9bf8;
  --c-gcp-soft:      #12233d;
  --c-gcp-text:      #8ab8fa;

  --c-ok:            #35b06a;
  --c-ok-soft:       #10281a;
  --c-ok-text:       #5fce90;
  --c-warn:          #d9a03c;
  --c-warn-soft:     #2b2110;
  --c-warn-text:     #e8bd68;
  --c-danger:        #e5675a;
  --c-danger-soft:   #2e1512;
  --c-danger-text:   #f19086;
  --c-info:          #7b8ce0;
  --c-info-soft:     #191d33;
  --c-info-text:     #a2aeed;

  --shadow-sm: 0 1px 2px rgba(0, 0, 0, .4);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, .45);
  --shadow-lg: 0 12px 32px rgba(0, 0, 0, .6);
}

/* ---------- 2. 基礎重置 ---------- */

*, *::before, *::after { box-sizing: border-box; }

html { scroll-behavior: smooth; }

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after {
    animation-duration: .01ms !important;
    transition-duration: .01ms !important;
  }
}

body {
  margin: 0;
  font-family: var(--font-sans);
  font-size: 15.5px;
  line-height: 1.75;
  color: var(--c-text);
  background: var(--c-bg);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

a { color: var(--c-gcp-text); text-decoration: none; }
a:hover { text-decoration: underline; }

button { font-family: inherit; font-size: inherit; cursor: pointer; }

:focus-visible {
  outline: 2px solid var(--c-gcp);
  outline-offset: 2px;
  border-radius: 3px;
}

.sr-only {
  position: absolute; width: 1px; height: 1px;
  padding: 0; margin: -1px; overflow: hidden;
  clip: rect(0, 0, 0, 0); white-space: nowrap; border: 0;
}

/* 跳至主要內容 */
.skip-link {
  position: absolute; left: 8px; top: -60px;
  background: var(--c-accent); color: #fff;
  padding: 10px 16px; border-radius: var(--radius);
  z-index: 200; transition: top var(--transition);
}
.skip-link:focus { top: 8px; }

/* ---------- 3. 版面骨架 ---------- */

.layout {
  display: grid;
  grid-template-columns: var(--sidebar-w) 1fr;
  min-height: 100vh;
}

/* ---------- 4. 側邊欄 ---------- */

.sidebar {
  grid-column: 1;
  background: var(--c-surface);
  border-right: 1px solid var(--c-border);
  display: flex;
  flex-direction: column;
  position: sticky;
  top: 0;
  height: 100vh;
  overflow: hidden;
  z-index: 60;
}

.sidebar__brand {
  padding: 16px 18px;
  border-bottom: 1px solid var(--c-border-soft);
  display: flex;
  align-items: center;
  gap: 11px;
  flex-shrink: 0;
}

.sidebar__logo {
  width: 34px; height: 34px;
  border-radius: 9px;
  background: linear-gradient(135deg, var(--c-accent), #7a0a1c 85%);
  color: #fff;
  display: grid; place-items: center;
  font-weight: 800; font-size: 15px;
  letter-spacing: -.5px;
  flex-shrink: 0;
}

.sidebar__title {
  font-size: 14.5px; font-weight: 700;
  line-height: 1.3; letter-spacing: -.2px;
}
.sidebar__subtitle {
  font-size: 11.5px; color: var(--c-text-3);
  line-height: 1.4; margin-top: 1px;
}

/* 進度條 */
.progress {
  padding: 13px 18px;
  border-bottom: 1px solid var(--c-border-soft);
  flex-shrink: 0;
}
.progress__head {
  display: flex; justify-content: space-between; align-items: baseline;
  font-size: 11.5px; color: var(--c-text-3);
  margin-bottom: 7px; font-weight: 600;
  letter-spacing: .02em;
}
.progress__pct { color: var(--c-text); font-variant-numeric: tabular-nums; }
.progress__track {
  height: 6px; border-radius: 99px;
  background: var(--c-surface-3);
  overflow: hidden;
}
.progress__fill {
  height: 100%;
  background: linear-gradient(90deg, var(--c-gcp), #34a853 90%);
  border-radius: 99px;
  transition: width 400ms cubic-bezier(.4, 0, .2, 1);
  width: 0;
}
.progress__reset {
  margin-top: 8px;
  background: none; border: none; padding: 0;
  font-size: 11px; color: var(--c-text-3);
  text-decoration: underline; text-underline-offset: 2px;
}
.progress__reset:hover { color: var(--c-danger-text); }

/* 導覽 */
.nav {
  flex: 1;
  overflow-y: auto;
  padding: 10px 10px 28px;
  scrollbar-width: thin;
}
.nav::-webkit-scrollbar { width: 9px; }
.nav::-webkit-scrollbar-thumb {
  background: var(--c-surface-3);
  border-radius: 99px;
  border: 3px solid var(--c-surface);
}

.nav__group-label {
  font-size: 10.5px; font-weight: 700;
  text-transform: uppercase; letter-spacing: .09em;
  color: var(--c-text-3);
  padding: 16px 10px 6px;
}

.nav__item {
  display: flex; align-items: center; gap: 9px;
  width: 100%;
  padding: 7px 10px;
  border: none; background: none;
  border-radius: var(--radius-sm);
  color: var(--c-text-2);
  font-size: 13.5px;
  text-align: left;
  line-height: 1.45;
  transition: background var(--transition), color var(--transition);
}
.nav__item:hover { background: var(--c-surface-2); color: var(--c-text); }
.nav__item.is-active {
  background: var(--c-accent-soft);
  color: var(--c-accent-text);
  font-weight: 650;
}
:root[data-theme="dark"] .nav__item.is-active { color: var(--c-accent-text); }

.nav__num {
  font-size: 10.5px;
  font-variant-numeric: tabular-nums;
  color: var(--c-text-3);
  min-width: 20px;
  font-weight: 600;
  flex-shrink: 0;
}
.nav__item.is-active .nav__num { color: var(--c-accent-text); }

.nav__label { flex: 1; min-width: 0; }

.nav__check {
  width: 15px; height: 15px;
  flex-shrink: 0;
  opacity: 0;
  color: var(--c-ok);
  transition: opacity var(--transition);
}
.nav__item.is-done .nav__check { opacity: 1; }
.nav__item.is-done .nav__label { color: var(--c-text-3); }

/* ---------- 5. 頂部列 ---------- */

.main-col {
  grid-column: 2;
  min-width: 0;
  display: flex;
  flex-direction: column;
}

.topbar {
  position: sticky; top: 0;
  height: var(--topbar-h);
  background: color-mix(in srgb, var(--c-bg) 88%, transparent);
  backdrop-filter: saturate(1.6) blur(12px);
  -webkit-backdrop-filter: saturate(1.6) blur(12px);
  border-bottom: 1px solid var(--c-border-soft);
  display: flex; align-items: center; gap: 12px;
  padding: 0 22px;
  z-index: 50;
  flex-shrink: 0;
}

.topbar__menu {
  display: none;
  width: 36px; height: 36px;
  border: 1px solid var(--c-border);
  background: var(--c-surface);
  border-radius: var(--radius-sm);
  place-items: center;
  color: var(--c-text-2);
  flex-shrink: 0;
}

/* 搜尋 */
.search {
  position: relative;
  flex: 1;
  max-width: 460px;
}
.search__icon {
  position: absolute; left: 11px; top: 50%;
  transform: translateY(-50%);
  color: var(--c-text-3);
  pointer-events: none;
  width: 15px; height: 15px;
}
.search__input {
  width: 100%;
  height: 37px;
  padding: 0 62px 0 34px;
  border: 1px solid var(--c-border);
  border-radius: var(--radius);
  background: var(--c-surface);
  color: var(--c-text);
  font-size: 13.5px;
  font-family: inherit;
  transition: border-color var(--transition), box-shadow var(--transition);
}
.search__input::placeholder { color: var(--c-text-3); }
.search__input:focus {
  outline: none;
  border-color: var(--c-gcp);
  box-shadow: 0 0 0 3px color-mix(in srgb, var(--c-gcp) 16%, transparent);
}
.search__kbd {
  position: absolute; right: 9px; top: 50%;
  transform: translateY(-50%);
  font-family: var(--font-mono);
  font-size: 10.5px;
  color: var(--c-text-3);
  background: var(--c-surface-2);
  border: 1px solid var(--c-border);
  border-bottom-width: 2px;
  border-radius: 4px;
  padding: 1px 5px;
  pointer-events: none;
}
.search__input:focus ~ .search__kbd,
.search__input:not(:placeholder-shown) ~ .search__kbd { opacity: 0; }

/* 搜尋結果 */
.search__results {
  position: absolute;
  top: calc(100% + 7px); left: 0; right: 0;
  background: var(--c-surface);
  border: 1px solid var(--c-border);
  border-radius: var(--radius);
  box-shadow: var(--shadow-lg);
  max-height: min(460px, 65vh);
  overflow-y: auto;
  padding: 5px;
  display: none;
  z-index: 90;
}
.search__results.is-open { display: block; }

.search__hit {
  display: block; width: 100%;
  text-align: left;
  padding: 8px 10px;
  border: none; background: none;
  border-radius: var(--radius-sm);
  line-height: 1.5;
}
.search__hit:hover, .search__hit.is-cursor { background: var(--c-surface-2); }
.search__hit-top {
  display: flex; align-items: center; gap: 7px;
  margin-bottom: 2px;
}
.search__hit-title {
  font-size: 13.5px; font-weight: 620; color: var(--c-text);
}
.search__hit-crumb {
  font-size: 10.5px; color: var(--c-text-3);
  background: var(--c-surface-2);
  padding: 1px 6px; border-radius: 99px;
  flex-shrink: 0;
}
.search__hit-snip {
  font-size: 12px; color: var(--c-text-3);
  display: -webkit-box; -webkit-line-clamp: 2; -webkit-box-orient: vertical;
  overflow: hidden;
}
.search__hit mark {
  background: color-mix(in srgb, var(--c-warn) 34%, transparent);
  color: inherit; border-radius: 2px; padding: 0 1px;
}
.search__empty {
  padding: 22px; text-align: center;
  color: var(--c-text-3); font-size: 13px;
}

/* 頂部控制項 */
.topbar__spacer { flex: 1; }
.topbar__tools { display: flex; align-items: center; gap: 8px; flex-shrink: 0; }

/* 難度切換 */
.level {
  display: flex;
  background: var(--c-surface-2);
  border: 1px solid var(--c-border);
  border-radius: var(--radius);
  padding: 2px;
  gap: 2px;
}
.level__btn {
  border: none; background: none;
  padding: 4px 11px;
  border-radius: var(--radius-sm) ;
  font-size: 12px; font-weight: 600;
  color: var(--c-text-3);
  transition: all var(--transition);
  white-space: nowrap;
}
.level__btn:hover { color: var(--c-text); }
.level__btn.is-active {
  background: var(--c-surface);
  color: var(--c-text);
  box-shadow: var(--shadow-sm);
}

.icon-btn {
  width: 36px; height: 36px;
  display: grid; place-items: center;
  border: 1px solid var(--c-border);
  background: var(--c-surface);
  border-radius: var(--radius-sm);
  color: var(--c-text-2);
  transition: all var(--transition);
  flex-shrink: 0;
}
.icon-btn:hover { background: var(--c-surface-2); color: var(--c-text); }
.icon-btn svg { width: 16px; height: 16px; }
.icon-btn .icon-moon { display: none; }
:root[data-theme="dark"] .icon-btn .icon-sun { display: none; }
:root[data-theme="dark"] .icon-btn .icon-moon { display: block; }

/* ---------- 6. 內容區 ---------- */

.content {
  flex: 1;
  padding: 40px 44px 120px;
  max-width: calc(var(--content-max) + 88px);
  width: 100%;
  margin: 0 auto;
}

.page { animation: fade-in 260ms cubic-bezier(.4, 0, .2, 1); }
@keyframes fade-in {
  from { opacity: 0; transform: translateY(6px); }
  to   { opacity: 1; transform: none; }
}

/* 麵包屑 */
.crumb {
  font-size: 12px; color: var(--c-text-3);
  margin-bottom: 10px;
  font-weight: 600; letter-spacing: .02em;
}

/* 標題 */
.page h1 {
  font-size: 32px; font-weight: 780;
  letter-spacing: -.7px; line-height: 1.25;
  margin: 0 0 10px;
}
.page h2 {
  font-size: 22px; font-weight: 720;
  letter-spacing: -.35px; line-height: 1.35;
  margin: 46px 0 14px;
  padding-bottom: 8px;
  border-bottom: 1px solid var(--c-border-soft);
  scroll-margin-top: calc(var(--topbar-h) + 20px);
}
.page h3 {
  font-size: 17px; font-weight: 680;
  letter-spacing: -.2px;
  margin: 30px 0 10px;
  scroll-margin-top: calc(var(--topbar-h) + 20px);
}
.page h4 {
  font-size: 14.5px; font-weight: 680;
  margin: 22px 0 8px;
  color: var(--c-text-2);
}
.page p { margin: 0 0 14px; }
.page ul, .page ol { margin: 0 0 14px; padding-left: 24px; }
.page li { margin-bottom: 6px; }
.page li > ul, .page li > ol { margin-top: 6px; margin-bottom: 4px; }

.page strong { font-weight: 680; color: var(--c-text); }

/* 引導段落 */
.lede {
  font-size: 16.5px;
  color: var(--c-text-2);
  line-height: 1.72;
  margin-bottom: 26px;
}

/* 一句話摘要 */
.tldr {
  background: var(--c-info-soft);
  border-left: 3px solid var(--c-info);
  border-radius: 0 var(--radius) var(--radius) 0;
  padding: 13px 17px;
  margin: 0 0 24px;
  font-size: 14.5px;
  line-height: 1.65;
}
.tldr__label {
  font-size: 10.5px; font-weight: 750;
  text-transform: uppercase; letter-spacing: .08em;
  color: var(--c-info-text);
  display: block; margin-bottom: 3px;
}

/* 為什麼重要 */
.why {
  background: var(--c-surface);
  border: 1px solid var(--c-border);
  border-radius: var(--radius);
  padding: 15px 18px;
  margin: 0 0 28px;
}
.why__label {
  font-size: 11px; font-weight: 750;
  text-transform: uppercase; letter-spacing: .07em;
  color: var(--c-text-3);
  display: block; margin-bottom: 5px;
}
.why p:last-child { margin-bottom: 0; }

/* ---------- 7. 來源可信度標籤 ---------- */

.tag {
  display: inline-flex; align-items: center; gap: 4px;
  font-size: 10.5px; font-weight: 700;
  padding: 2px 8px;
  border-radius: 99px;
  letter-spacing: .02em;
  white-space: nowrap;
  vertical-align: middle;
  border: 1px solid transparent;
  line-height: 1.6;
}
.tag--confirmed {
  background: var(--c-ok-soft); color: var(--c-ok-text);
  border-color: color-mix(in srgb, var(--c-ok) 32%, transparent);
}
.tag--inferred {
  background: var(--c-info-soft); color: var(--c-info-text);
  border-color: color-mix(in srgb, var(--c-info) 32%, transparent);
}
.tag--unverified {
  background: var(--c-warn-soft); color: var(--c-warn-text);
  border-color: color-mix(in srgb, var(--c-warn) 36%, transparent);
}
.tag--vendor {
  background: var(--c-accent-soft); color: var(--c-accent-text);
  border-color: color-mix(in srgb, var(--c-accent) 30%, transparent);
}
.tag--gcp {
  background: var(--c-gcp-soft); color: var(--c-gcp-text);
  border-color: color-mix(in srgb, var(--c-gcp) 30%, transparent);
}
.tag--neutral {
  background: var(--c-surface-2); color: var(--c-text-3);
  border-color: var(--c-border);
}

/* 標籤圖例 */
.legend {
  display: flex; flex-wrap: wrap; gap: 8px 16px;
  padding: 13px 16px;
  background: var(--c-surface-2);
  border-radius: var(--radius);
  margin-bottom: 26px;
  font-size: 12px;
  color: var(--c-text-2);
}
.legend__item { display: flex; align-items: center; gap: 6px; }

/* ---------- 8. 訊息框 ---------- */

.callout {
  border-radius: var(--radius);
  padding: 14px 17px;
  margin: 20px 0;
  border: 1px solid;
  font-size: 14px;
  line-height: 1.68;
}
.callout__title {
  font-weight: 700; font-size: 13.5px;
  margin-bottom: 5px;
  display: flex; align-items: center; gap: 7px;
}
.callout p:last-child, .callout ul:last-child { margin-bottom: 0; }
.callout ul { padding-left: 20px; }

.callout--warn {
  background: var(--c-warn-soft);
  border-color: color-mix(in srgb, var(--c-warn) 38%, transparent);
  color: var(--c-warn-text);
}
.callout--danger {
  background: var(--c-danger-soft);
  border-color: color-mix(in srgb, var(--c-danger) 38%, transparent);
  color: var(--c-danger-text);
}
.callout--info {
  background: var(--c-info-soft);
  border-color: color-mix(in srgb, var(--c-info) 34%, transparent);
  color: var(--c-info-text);
}
.callout--ok {
  background: var(--c-ok-soft);
  border-color: color-mix(in srgb, var(--c-ok) 34%, transparent);
  color: var(--c-ok-text);
}
.callout--cost {
  background: var(--c-surface-2);
  border-color: var(--c-border);
  color: var(--c-text-2);
}
.callout a { color: inherit; text-decoration: underline; font-weight: 600; }

/* ---------- 9. 表格 ---------- */

.table-wrap {
  overflow-x: auto;
  margin: 20px 0;
  border: 1px solid var(--c-border);
  border-radius: var(--radius);
  background: var(--c-surface);
  -webkit-overflow-scrolling: touch;
}
table {
  width: 100%;
  border-collapse: collapse;
  font-size: 13px;
  min-width: 520px;
}
th, td {
  padding: 10px 13px;
  text-align: left;
  vertical-align: top;
  border-bottom: 1px solid var(--c-border-soft);
  line-height: 1.6;
}
th {
  background: var(--c-surface-2);
  font-weight: 680;
  font-size: 12px;
  color: var(--c-text-2);
  white-space: nowrap;
  position: sticky; top: 0;
  letter-spacing: .01em;
}
tbody tr:last-child td { border-bottom: none; }
tbody tr:hover td { background: var(--c-surface-2); }
td code { font-size: 11.5px; }

/* ---------- 10. 程式碼區塊 ---------- */

code {
  font-family: var(--font-mono);
  font-size: .875em;
  background: var(--c-surface-2);
  padding: .13em .38em;
  border-radius: 4px;
  border: 1px solid var(--c-border-soft);
  word-break: break-word;
}

.code {
  margin: 18px 0;
  border: 1px solid var(--c-border);
  border-radius: var(--radius);
  overflow: hidden;
  background: var(--c-surface);
}
.code__head {
  display: flex; align-items: center; gap: 10px;
  padding: 7px 8px 7px 13px;
  background: var(--c-surface-2);
  border-bottom: 1px solid var(--c-border);
  font-size: 11.5px;
}
.code__lang {
  font-family: var(--font-mono);
  color: var(--c-text-3);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: .05em;
  font-size: 10.5px;
}
.code__note {
  color: var(--c-text-3);
  flex: 1;
  overflow: hidden; text-overflow: ellipsis; white-space: nowrap;
}
.code__copy {
  border: 1px solid var(--c-border);
  background: var(--c-surface);
  color: var(--c-text-2);
  border-radius: var(--radius-sm);
  padding: 3px 9px;
  font-size: 11.5px;
  font-weight: 600;
  display: flex; align-items: center; gap: 5px;
  flex-shrink: 0;
  transition: all var(--transition);
}
.code__copy:hover { background: var(--c-surface-3); color: var(--c-text); }
.code__copy.is-copied {
  background: var(--c-ok-soft);
  color: var(--c-ok-text);
  border-color: color-mix(in srgb, var(--c-ok) 40%, transparent);
}
.code__copy svg { width: 12px; height: 12px; }

.code pre {
  margin: 0;
  padding: 14px 15px;
  overflow-x: auto;
  font-family: var(--font-mono);
  font-size: 12.5px;
  line-height: 1.68;
  -webkit-overflow-scrolling: touch;
}
.code pre code {
  background: none; border: none; padding: 0;
  font-size: inherit; word-break: normal;
}

/* ---------- 11. 可展開細節 ---------- */

.details {
  border: 1px solid var(--c-border);
  border-radius: var(--radius);
  margin: 16px 0;
  background: var(--c-surface);
  overflow: hidden;
}
.details > summary {
  padding: 11px 15px;
  cursor: pointer;
  font-weight: 640;
  font-size: 13.5px;
  color: var(--c-text-2);
  list-style: none;
  display: flex; align-items: center; gap: 9px;
  transition: background var(--transition);
  user-select: none;
}
.details > summary::-webkit-details-marker { display: none; }
.details > summary:hover { background: var(--c-surface-2); color: var(--c-text); }
.details > summary::before {
  content: "";
  width: 0; height: 0;
  border-left: 5px solid currentColor;
  border-top: 4px solid transparent;
  border-bottom: 4px solid transparent;
  transition: transform var(--transition);
  flex-shrink: 0;
  opacity: .6;
}
.details[open] > summary::before { transform: rotate(90deg); }
.details[open] > summary {
  border-bottom: 1px solid var(--c-border-soft);
  background: var(--c-surface-2);
}
.details__body { padding: 15px; }
.details__body > :first-child { margin-top: 0; }
.details__body > :last-child { margin-bottom: 0; }

/* ---------- 12. 卡片 ---------- */

.cards {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(258px, 1fr));
  gap: 14px;
  margin: 20px 0;
}

.card {
  border: 1px solid var(--c-border);
  border-radius: var(--radius-lg);
  padding: 17px;
  background: var(--c-surface);
  text-align: left;
  transition: all var(--transition);
  display: flex; flex-direction: column;
  width: 100%;
}
button.card:hover, a.card:hover {
  border-color: var(--c-gcp);
  box-shadow: var(--shadow-md);
  transform: translateY(-2px);
  text-decoration: none;
}
.card__top {
  display: flex; align-items: center; gap: 8px;
  margin-bottom: 8px; flex-wrap: wrap;
}
.card__title {
  font-size: 14.5px; font-weight: 690;
  color: var(--c-text);
  line-height: 1.4;
}
.card__desc {
  font-size: 12.5px; color: var(--c-text-3);
  line-height: 1.6;
  flex: 1;
}
.card__meta {
  margin-top: 11px;
  padding-top: 10px;
  border-top: 1px solid var(--c-border-soft);
  font-size: 11px; color: var(--c-text-3);
  display: flex; gap: 12px; flex-wrap: wrap;
}
.card__meta span { display: flex; align-items: center; gap: 4px; }

/* ---------- 13. 學習路徑 ---------- */

.paths {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 15px;
  margin: 24px 0 34px;
}
.path {
  border: 1px solid var(--c-border);
  border-radius: var(--radius-lg);
  padding: 20px;
  background: var(--c-surface);
  display: flex; flex-direction: column;
  position: relative;
  overflow: hidden;
}
.path::before {
  content: "";
  position: absolute; inset: 0 0 auto 0;
  height: 3px;
  background: var(--path-color, var(--c-gcp));
}
.path--quick  { --path-color: #34a853; }
.path--intro  { --path-color: var(--c-gcp); }
.path--deep   { --path-color: var(--c-accent); }

.path__time {
  font-size: 11px; font-weight: 750;
  letter-spacing: .06em; text-transform: uppercase;
  color: var(--path-color);
  margin-bottom: 6px;
}
.path__title {
  font-size: 17px; font-weight: 720;
  letter-spacing: -.25px;
  margin-bottom: 7px;
}
.path__goal {
  font-size: 13px; color: var(--c-text-3);
  line-height: 1.62;
  margin-bottom: 14px;
}
.path__steps {
  list-style: none; padding: 0; margin: 0 0 16px;
  flex: 1;
  counter-reset: pstep;
}
.path__steps li {
  font-size: 12.5px;
  padding: 4px 0 4px 26px;
  position: relative;
  color: var(--c-text-2);
  counter-increment: pstep;
  margin: 0;
}
.path__steps li::before {
  content: counter(pstep);
  position: absolute; left: 0; top: 6px;
  width: 17px; height: 17px;
  border-radius: 50%;
  background: var(--c-surface-3);
  color: var(--c-text-3);
  font-size: 9.5px; font-weight: 750;
  display: grid; place-items: center;
}
.path__steps li a { color: var(--c-text-2); }
.path__steps li a:hover { color: var(--path-color); }

.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 7px;
  padding: 9px 16px;
  border-radius: var(--radius);
  border: 1px solid var(--c-border);
  background: var(--c-surface-2);
  color: var(--c-text);
  font-size: 13px; font-weight: 640;
  transition: all var(--transition);
  text-decoration: none;
}
.btn:hover { background: var(--c-surface-3); text-decoration: none; }
.btn--primary {
  background: var(--path-color, var(--c-gcp));
  border-color: transparent;
  color: #fff;
}
.btn--primary:hover { filter: brightness(1.08); }

/* ---------- 14. Mermaid 圖 ---------- */

.diagram {
  margin: 22px 0;
  border: 1px solid var(--c-border);
  border-radius: var(--radius);
  background: var(--c-surface);
  overflow: hidden;
}
.diagram__cap {
  padding: 8px 14px;
  font-size: 11.5px; font-weight: 640;
  color: var(--c-text-3);
  background: var(--c-surface-2);
  border-bottom: 1px solid var(--c-border);
}
.diagram__cap {
  display: flex; align-items: center; gap: 10px;
  justify-content: space-between;
}
.diagram__hint {
  font-size: 10.5px; font-weight: 600;
  color: var(--c-text-3);
  border: 1px solid var(--c-border);
  border-radius: 99px;
  padding: 1px 8px;
  white-space: nowrap;
  flex-shrink: 0;
  transition: all var(--transition);
}
.diagram:hover .diagram__hint {
  border-color: var(--c-gcp);
  color: var(--c-gcp-text);
  background: var(--c-gcp-soft);
}

.diagram__body {
  padding: 18px 14px;
  overflow-x: auto;
  text-align: center;
  -webkit-overflow-scrolling: touch;
  cursor: zoom-in;
}
/* ⚠️ .mermaid 必須是 block 且有明確寬度。
   Mermaid 在 useMaxWidth:true 時會給 svg 加上 width:100% + inline 的 max-width，
   百分比寬度碰上 inline-block 這種收縮容器會直接塌掉 —— 圖會被縮到約 1/4 大。 */
.diagram__body .mermaid { display: block; width: 100%; }
.diagram__body svg { height: auto; margin: 0 auto; }

/* fallback（未渲染成 SVG）時放大沒有意義 */
.diagram__body:has(.diagram__fallback) { cursor: default; }
.diagram__body:has(.diagram__fallback) ~ * .diagram__hint,
.diagram:has(.diagram__fallback) .diagram__hint { display: none; }

/* ---------- 14b. 圖表放大檢視器 ---------- */

body.is-locked { overflow: hidden; }

.zoom {
  position: fixed; inset: 0;
  z-index: 200;
  background: color-mix(in srgb, var(--c-bg) 96%, #000);
  display: flex; flex-direction: column;
  opacity: 0;
  transition: opacity 180ms cubic-bezier(.4, 0, .2, 1);
}
.zoom.is-open { opacity: 1; }

.zoom__bar {
  display: flex; align-items: center; gap: 14px;
  padding: 11px 16px;
  border-bottom: 1px solid var(--c-border);
  background: var(--c-surface);
  flex-shrink: 0;
}
.zoom__cap {
  font-size: 13.5px; font-weight: 640;
  color: var(--c-text);
  flex: 1; min-width: 0;
  overflow: hidden; text-overflow: ellipsis; white-space: nowrap;
}
.zoom__ctrls { display: flex; gap: 6px; flex-shrink: 0; }

.zoom__btn {
  width: 34px; height: 34px;
  display: grid; place-items: center;
  border: 1px solid var(--c-border);
  background: var(--c-surface-2);
  border-radius: var(--radius-sm);
  color: var(--c-text-2);
  font-size: 15px; line-height: 1;
  transition: all var(--transition);
}
.zoom__btn:hover { background: var(--c-surface-3); color: var(--c-text); }
.zoom__btn--close:hover {
  background: var(--c-danger); border-color: var(--c-danger); color: #fff;
}

.zoom__stage {
  flex: 1;
  overflow: hidden;
  display: grid; place-items: center;
  cursor: grab;
  touch-action: none;
  position: relative;
}
.zoom__stage.is-grabbing { cursor: grabbing; }

.zoom__inner {
  transform-origin: center center;
  will-change: transform;
  pointer-events: none;  /* 讓拖曳事件都落在 stage 上 */
}
.zoom__inner svg { display: block; }

.zoom__foot {
  padding: 9px 16px;
  border-top: 1px solid var(--c-border);
  background: var(--c-surface);
  font-size: 11.5px;
  color: var(--c-text-3);
  text-align: center;
  flex-shrink: 0;
}
.zoom__foot kbd {
  font-family: var(--font-mono);
  font-size: 10.5px;
  background: var(--c-surface-2);
  border: 1px solid var(--c-border);
  border-bottom-width: 2px;
  border-radius: 4px;
  padding: 1px 5px;
  margin: 0 1px;
}

@media (max-width: 560px) {
  .zoom__cap { font-size: 12px; }
  .zoom__foot { font-size: 10.5px; }
}
.diagram__fallback {
  padding: 16px;
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--c-text-3);
  white-space: pre-wrap;
  text-align: left;
}

/* ---------- 15. 測驗 ---------- */

.quiz {
  border: 1px solid var(--c-border);
  border-radius: var(--radius-lg);
  padding: 19px;
  margin: 18px 0;
  background: var(--c-surface);
}
.quiz__q {
  font-weight: 660;
  font-size: 14.5px;
  margin-bottom: 13px;
  line-height: 1.6;
  display: flex; gap: 9px;
}
.quiz__qnum {
  color: var(--c-text-3);
  font-variant-numeric: tabular-nums;
  flex-shrink: 0;
  font-weight: 750;
}
.quiz__scenario {
  background: var(--c-surface-2);
  border-radius: var(--radius-sm);
  padding: 11px 13px;
  font-size: 13px;
  color: var(--c-text-2);
  margin-bottom: 13px;
  line-height: 1.65;
  border-left: 2px solid var(--c-info);
}
.quiz__opts { display: flex; flex-direction: column; gap: 7px; }
.quiz__opt {
  display: flex; align-items: flex-start; gap: 10px;
  padding: 10px 13px;
  border: 1px solid var(--c-border);
  border-radius: var(--radius);
  background: var(--c-surface);
  font-size: 13.5px;
  text-align: left;
  line-height: 1.6;
  transition: all var(--transition);
  width: 100%;
}
.quiz__opt:hover:not(:disabled) {
  border-color: var(--c-gcp);
  background: var(--c-gcp-soft);
}
.quiz__opt:disabled { cursor: default; }
.quiz__opt-key {
  width: 19px; height: 19px;
  border-radius: 50%;
  border: 1.5px solid var(--c-border);
  display: grid; place-items: center;
  font-size: 10.5px; font-weight: 750;
  color: var(--c-text-3);
  flex-shrink: 0;
  margin-top: 1px;
}
.quiz__opt.is-correct {
  border-color: var(--c-ok);
  background: var(--c-ok-soft);
}
.quiz__opt.is-correct .quiz__opt-key {
  background: var(--c-ok); border-color: var(--c-ok); color: #fff;
}
.quiz__opt.is-wrong {
  border-color: var(--c-danger);
  background: var(--c-danger-soft);
}
.quiz__opt.is-wrong .quiz__opt-key {
  background: var(--c-danger); border-color: var(--c-danger); color: #fff;
}

.quiz__explain {
  margin-top: 13px;
  padding: 12px 14px;
  border-radius: var(--radius);
  background: var(--c-surface-2);
  font-size: 13px;
  line-height: 1.68;
  border-left: 3px solid var(--c-info);
  display: none;
}
.quiz__explain.is-open { display: block; }
.quiz__explain-label {
  font-size: 10.5px; font-weight: 750;
  text-transform: uppercase; letter-spacing: .07em;
  color: var(--c-text-3);
  display: block; margin-bottom: 4px;
}
.quiz__misconception {
  margin-top: 9px;
  padding-top: 9px;
  border-top: 1px dashed var(--c-border);
  font-size: 12.5px;
  color: var(--c-text-3);
}

/* 測驗計分 */
.quiz-score {
  border: 1px solid var(--c-border);
  border-radius: var(--radius-lg);
  padding: 22px;
  background: var(--c-surface);
  margin: 22px 0;
  text-align: center;
}
.quiz-score__num {
  font-size: 40px; font-weight: 800;
  letter-spacing: -1.5px;
  font-variant-numeric: tabular-nums;
  line-height: 1.1;
}
.quiz-score__label { font-size: 13px; color: var(--c-text-3); margin-bottom: 14px; }
.quiz-score__advice {
  font-size: 13.5px; color: var(--c-text-2);
  text-align: left;
  background: var(--c-surface-2);
  border-radius: var(--radius);
  padding: 13px 15px;
  line-height: 1.7;
}

/* ---------- 16. 難度分層內容 ---------- */

.lvl { display: none; }
:root[data-level="beginner"] .lvl--beginner,
:root[data-level="practical"] .lvl--practical,
:root[data-level="advanced"] .lvl--advanced { display: block; }

/* 進階內容在初學模式收合為提示 */
.lvl-hint {
  display: none;
  font-size: 12.5px;
  color: var(--c-text-3);
  background: var(--c-surface-2);
  border: 1px dashed var(--c-border);
  border-radius: var(--radius);
  padding: 11px 14px;
  margin: 16px 0;
}
:root[data-level="beginner"] .lvl-hint--advanced { display: block; }

/* ---------- 17. 章節完成 ---------- */

.chapter-done {
  margin-top: 54px;
  padding: 20px;
  border: 1px solid var(--c-border);
  border-radius: var(--radius-lg);
  background: var(--c-surface);
  display: flex; align-items: center; gap: 15px;
  flex-wrap: wrap;
}
.chapter-done__text { flex: 1; min-width: 190px; }
.chapter-done__title { font-weight: 680; font-size: 14.5px; margin-bottom: 3px; }
.chapter-done__hint { font-size: 12.5px; color: var(--c-text-3); line-height: 1.6; }

.mark-btn {
  border: 1px solid var(--c-ok);
  background: var(--c-ok);
  color: #fff;
  padding: 9px 17px;
  border-radius: var(--radius);
  font-weight: 650; font-size: 13px;
  display: flex; align-items: center; gap: 7px;
  flex-shrink: 0;
  transition: all var(--transition);
}
.mark-btn:hover { filter: brightness(1.08); }
.mark-btn.is-done {
  background: var(--c-surface-2);
  color: var(--c-text-3);
  border-color: var(--c-border);
}
.mark-btn svg { width: 14px; height: 14px; }

/* 上下頁 */
.pager {
  display: flex; justify-content: space-between; gap: 12px;
  margin-top: 22px;
  flex-wrap: wrap;
}
.pager__btn {
  flex: 1; min-width: 175px;
  border: 1px solid var(--c-border);
  border-radius: var(--radius);
  background: var(--c-surface);
  padding: 12px 15px;
  text-align: left;
  transition: all var(--transition);
}
.pager__btn:hover { border-color: var(--c-gcp); box-shadow: var(--shadow-sm); }
.pager__btn--next { text-align: right; }
.pager__dir { font-size: 10.5px; color: var(--c-text-3); font-weight: 700; letter-spacing: .06em; }
.pager__name { font-size: 13.5px; font-weight: 640; margin-top: 2px; color: var(--c-text); }

/* ---------- 18. 術語表 ---------- */

.glossary-filter {
  display: flex; gap: 9px; margin-bottom: 20px; flex-wrap: wrap;
}
.glossary-filter input {
  flex: 1; min-width: 190px;
  height: 38px; padding: 0 13px;
  border: 1px solid var(--c-border);
  border-radius: var(--radius);
  background: var(--c-surface);
  color: var(--c-text);
  font-family: inherit; font-size: 13.5px;
}
.glossary-filter input:focus {
  outline: none; border-color: var(--c-gcp);
  box-shadow: 0 0 0 3px color-mix(in srgb, var(--c-gcp) 16%, transparent);
}
.chip {
  padding: 0 13px; height: 38px;
  border: 1px solid var(--c-border);
  background: var(--c-surface);
  border-radius: var(--radius);
  font-size: 12.5px; font-weight: 620;
  color: var(--c-text-2);
  transition: all var(--transition);
}
.chip:hover { background: var(--c-surface-2); }
.chip.is-active {
  background: var(--c-text); color: var(--c-bg);
  border-color: var(--c-text);
}

.term {
  border-bottom: 1px solid var(--c-border-soft);
  padding: 13px 0;
}
.term__head {
  display: flex; align-items: center; gap: 9px;
  margin-bottom: 3px; flex-wrap: wrap;
}
.term__name { font-weight: 680; font-size: 14.5px; }
.term__zh { color: var(--c-text-3); font-size: 13px; }
.term__def { font-size: 13.5px; color: var(--c-text-2); line-height: 1.68; }

/* ---------- 19. 來源索引 ---------- */

.src {
  padding: 11px 0;
  border-bottom: 1px solid var(--c-border-soft);
  font-size: 13px;
}
.src__title { font-weight: 620; margin-bottom: 2px; }
.src__meta {
  font-size: 11.5px; color: var(--c-text-3);
  display: flex; gap: 9px; flex-wrap: wrap;
  align-items: center;
}
.src__url {
  font-family: var(--font-mono);
  font-size: 11px;
  word-break: break-all;
}

/* ---------- 20. 響應式 ---------- */

.backdrop {
  display: none;
  position: fixed; inset: 0;
  background: rgba(8, 11, 16, .5);
  z-index: 55;
  backdrop-filter: blur(2px);
}
.backdrop.is-open { display: block; }

@media (max-width: 1080px) {
  .content { padding: 32px 26px 100px; }
}

@media (max-width: 900px) {
  .layout { grid-template-columns: 1fr; }

  .sidebar {
    position: fixed;
    left: 0; top: 0; bottom: 0;
    width: min(300px, 86vw);
    transform: translateX(-100%);
    transition: transform 220ms cubic-bezier(.4, 0, .2, 1);
    box-shadow: var(--shadow-lg);
  }
  .sidebar.is-open { transform: none; }

  .main-col { grid-column: 1; }
  .topbar__menu { display: grid; }
  .topbar { padding: 0 14px; gap: 9px; }
  .search { max-width: none; }
  .search__kbd { display: none; }
  .level__btn { padding: 4px 8px; font-size: 11px; }

  .content { padding: 26px 18px 90px; }
  .page h1 { font-size: 25px; }
  .page h2 { font-size: 19px; margin-top: 36px; }
  .page h3 { font-size: 16px; }
  .lede { font-size: 15px; }
  body { font-size: 15px; }

  .cards, .paths { grid-template-columns: 1fr; }
}

@media (max-width: 560px) {
  .topbar__tools .level { display: none; }
  .content { padding: 20px 14px 80px; }
  .pager__btn { min-width: 100%; }
  .quiz, .card, .path { padding: 15px; }
  .code pre { font-size: 11.5px; }
}

/* ---------- 21. 列印 ---------- */

@media print {
  .sidebar, .topbar, .backdrop, .pager, .chapter-done, .code__copy,
  .zoom, .diagram__hint { display: none !important; }
  .layout { grid-template-columns: 1fr; }
  .content { max-width: none; padding: 0; }
  .details { border: none; }
  .details__body { display: block !important; }
  .lvl { display: block !important; }
  body { background: #fff; color: #000; font-size: 11pt; }
  a::after { content: " (" attr(href) ")"; font-size: 9pt; color: #555; }
}