/* 電腦網路白話讀本 — 安靜的編輯式閱讀系統
   色票沿用 --line / --indigo / --paper / --ink-dim 等命名，
   讓劃記系統（annotations.js）可以直接沿用同一組 token。 */

:root {
  --paper: #FAF9F6;
  --paper-raised: #FFFFFF;
  --ink: #1A1D21;
  --ink-dim: #5B6470;
  --ink-faint: #8A93A0;
  --line: #E4E1D9;
  --line-soft: #EFEDE7;

  --indigo: #1D4E89;
  --indigo-deep: #14385F;
  --indigo-soft: #E9F0F8;
  --teal: #0F7B6C;
  --teal-soft: #E4F2EF;
  --amber: #9A6410;
  --amber-soft: #FBF1DD;
  --rose: #A33A2A;
  --rose-soft: #FAEAE6;

  --measure: 34rem;
  --radius: 10px;
  --nav-h: 53px;

  --serif: "Noto Serif TC", "Songti TC", "Source Han Serif TC", "PingFang TC", Georgia, serif;
  --sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang TC",
    "Noto Sans TC", "Microsoft JhengHei", Roboto, sans-serif;
  --mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, monospace;
}

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

html {
  -webkit-text-size-adjust: 100%;
  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;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 17px;
  line-height: 1.85;
  letter-spacing: .01em;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

button { font-family: inherit; cursor: pointer; }
button:focus-visible,
a:focus-visible {
  outline: 2px solid var(--indigo);
  outline-offset: 2px;
}

.skip-link {
  position: absolute;
  left: -9999px;
  top: 0;
  z-index: 50;
  padding: 10px 16px;
  background: var(--indigo);
  color: #FFF;
  border-radius: 0 0 var(--radius) 0;
  text-decoration: none;
}
.skip-link:focus { left: 0; }

.view {
  max-width: calc(var(--measure) + 44px);
  margin: 0 auto;
  padding: 0 22px calc(72px + env(safe-area-inset-bottom));
  outline: none;
}

/* ── 首頁 ───────────────────────────────────────── */

.home-head {
  padding: 46px 0 26px;
  border-bottom: 1px solid var(--line);
}

.home-kicker {
  margin: 0 0 10px;
  font-size: 12px;
  letter-spacing: .18em;
  text-transform: uppercase;
  color: var(--ink-faint);
}

.home-title {
  margin: 0;
  font-family: var(--serif);
  font-size: 34px;
  line-height: 1.3;
  font-weight: 700;
  letter-spacing: -.01em;
}

.home-lede {
  margin: 14px 0 0;
  color: var(--ink-dim);
  font-size: 15.5px;
  line-height: 1.8;
}

.home-source {
  margin: 18px 0 0;
  padding: 12px 14px;
  background: var(--paper-raised);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  font-size: 13px;
  line-height: 1.75;
  color: var(--ink-dim);
}
.home-source strong { color: var(--ink); font-weight: 600; }

.progress-block { padding: 24px 0 6px; }

.progress-row {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 12px;
  margin-bottom: 10px;
}

.progress-label {
  font-size: 13px;
  color: var(--ink-dim);
  letter-spacing: .04em;
}

.progress-count {
  font-family: var(--mono);
  font-size: 13px;
  color: var(--indigo);
  font-variant-numeric: tabular-nums;
}

.progress-track {
  height: 5px;
  border-radius: 99px;
  background: var(--line-soft);
  overflow: hidden;
}

.progress-fill {
  height: 100%;
  border-radius: 99px;
  background: var(--indigo);
  transition: width .4s ease;
}

.resume-card {
  display: block;
  width: 100%;
  margin: 20px 0 0;
  padding: 16px 18px;
  text-align: left;
  background: var(--indigo-soft);
  border: 1px solid color-mix(in srgb, var(--indigo) 26%, transparent);
  border-radius: var(--radius);
  color: inherit;
}
.resume-card:hover { border-color: var(--indigo); }

.resume-kicker {
  display: block;
  font-size: 11.5px;
  letter-spacing: .14em;
  text-transform: uppercase;
  color: var(--indigo);
  margin-bottom: 6px;
}

.resume-title {
  display: block;
  font-weight: 600;
  font-size: 16px;
  line-height: 1.5;
}

.resume-sub {
  display: block;
  margin-top: 4px;
  font-size: 13.5px;
  color: var(--ink-dim);
}

.section-label {
  margin: 40px 0 4px;
  font-size: 12px;
  letter-spacing: .16em;
  text-transform: uppercase;
  color: var(--ink-faint);
}

.ch-list {
  list-style: none;
  margin: 0;
  padding: 0;
  border-top: 1px solid var(--line);
}

.ch-list li { border-bottom: 1px solid var(--line); }

.ch-link {
  display: grid;
  grid-template-columns: 30px 1fr auto;
  align-items: baseline;
  gap: 14px;
  padding: 18px 4px;
  text-decoration: none;
  color: inherit;
}
.ch-link:hover .ch-link-title { color: var(--indigo); }

.ch-num {
  font-family: var(--mono);
  font-size: 12.5px;
  color: var(--ink-faint);
  font-variant-numeric: tabular-nums;
}

.ch-link-title {
  font-family: var(--serif);
  font-size: 18px;
  font-weight: 600;
  line-height: 1.5;
  transition: color .15s;
}

.ch-link-sub {
  display: block;
  margin-top: 3px;
  font-family: var(--sans);
  font-size: 12.5px;
  font-weight: 400;
  color: var(--ink-faint);
  letter-spacing: .01em;
}

.ch-badge {
  align-self: center;
  font-size: 11.5px;
  padding: 3px 9px;
  border-radius: 99px;
  white-space: nowrap;
  background: var(--teal-soft);
  color: var(--teal);
  font-weight: 600;
}
.ch-badge[data-state="todo"] { visibility: hidden; }

.home-foot {
  margin-top: 44px;
  padding-top: 20px;
  border-top: 1px solid var(--line);
  font-size: 12.5px;
  line-height: 1.9;
  color: var(--ink-faint);
}
.home-foot p { margin: 0 0 8px; }

.reset-btn {
  margin-top: 6px;
  padding: 6px 12px;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: var(--paper-raised);
  color: var(--ink-dim);
  font-size: 12.5px;
}
.reset-btn:hover { border-color: var(--rose); color: var(--rose); }

/* ── 章節導覽列 ─────────────────────────────────── */

.ch-nav {
  position: sticky;
  top: 0;
  z-index: 10;
  display: flex;
  align-items: center;
  gap: 10px;
  margin: 0 -22px;
  padding: 10px 22px;
  background: color-mix(in srgb, var(--paper) 92%, transparent);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--line);
}

.ch-nav-home {
  flex: none;
  padding: 5px 10px;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: var(--paper-raised);
  color: var(--ink-dim);
  font-size: 13px;
  text-decoration: none;
}
.ch-nav-home:hover { border-color: var(--indigo); color: var(--indigo); }

.ch-nav-pos {
  flex: 1;
  min-width: 0;
  font-family: var(--mono);
  font-size: 12px;
  color: var(--ink-faint);
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

/* ── 章節本文 ───────────────────────────────────── */

.ch-head { padding: 30px 0 6px; }

.ch-eyebrow {
  margin: 0 0 10px;
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: .1em;
  color: var(--indigo);
}

.ch-title {
  margin: 0;
  font-family: var(--serif);
  font-size: 29px;
  line-height: 1.38;
  font-weight: 700;
  letter-spacing: -.005em;
}

.ch-subtitle {
  margin: 8px 0 0;
  font-size: 13.5px;
  color: var(--ink-faint);
  font-style: italic;
  letter-spacing: .01em;
}

.analogy {
  margin: 26px 0 8px;
  padding: 20px 20px 18px;
  background: var(--amber-soft);
  border: 1px solid color-mix(in srgb, var(--amber) 24%, transparent);
  border-radius: var(--radius);
}

.analogy-title {
  margin: 0 0 10px;
  font-family: var(--serif);
  font-size: 17px;
  font-weight: 700;
  color: var(--amber);
  line-height: 1.5;
}

.analogy p {
  margin: 0 0 12px;
  font-size: 16px;
  line-height: 1.9;
}
.analogy p:last-child { margin-bottom: 0; }

.ch-section {
  padding: 30px 0 4px;
  border-top: 1px solid var(--line-soft);
  margin-top: 22px;
}
.ch-section:first-of-type { border-top: none; }

.sec-title {
  margin: 0 0 14px;
  font-family: var(--serif);
  font-size: 20px;
  font-weight: 700;
  line-height: 1.55;
  scroll-margin-top: calc(var(--nav-h) + 12px);
}

.ch-section p {
  margin: 0 0 16px;
  line-height: 1.95;
  text-wrap: pretty;
}

.ch-section p strong {
  font-weight: 700;
  color: var(--indigo-deep);
}

code {
  font-family: var(--mono);
  font-size: .87em;
  padding: 1px 5px;
  border-radius: 4px;
  background: var(--indigo-soft);
  color: var(--indigo-deep);
  word-break: break-word;
}

.terms {
  margin: 18px 0 6px;
  padding: 0;
  list-style: none;
  border-left: 2px solid var(--teal);
  padding-left: 14px;
}

.term {
  margin: 0 0 12px;
  font-size: 14.5px;
  line-height: 1.75;
}
.term:last-child { margin-bottom: 0; }

.term-plain { color: var(--ink-dim); }

.term-arrow {
  color: var(--teal);
  margin: 0 7px;
  font-weight: 700;
}

.term-formal {
  font-weight: 700;
  color: var(--ink);
}

.term-en {
  display: block;
  font-family: var(--mono);
  font-size: 12px;
  color: var(--ink-faint);
  letter-spacing: .01em;
  margin-top: 1px;
}

.caveat {
  margin: 18px 0 6px;
  padding: 14px 16px;
  background: var(--rose-soft);
  border-left: 3px solid var(--rose);
  border-radius: 0 var(--radius) var(--radius) 0;
  font-size: 14.5px;
  line-height: 1.8;
}
.caveat strong { color: var(--rose); }
.caveat p { margin: 0 0 10px; }
.caveat p:last-child { margin-bottom: 0; }

/* ── 互動圖 ─────────────────────────────────────── */

.diagram {
  margin: 30px 0 10px;
  padding: 18px;
  background: var(--paper-raised);
  border: 1px solid var(--line);
  border-radius: var(--radius);
}

.diagram-title {
  margin: 0 0 4px;
  font-size: 14px;
  font-weight: 700;
  letter-spacing: .02em;
}

.diagram-caption {
  margin: 0 0 16px;
  font-size: 13px;
  line-height: 1.75;
  color: var(--ink-dim);
}

.diagram-stage {
  position: relative;
  overflow-x: auto;
  overscroll-behavior-x: contain;
}

.diagram-controls {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  align-items: center;
  margin-top: 14px;
  padding-top: 14px;
  border-top: 1px dashed var(--line);
}

.dg-btn {
  padding: 6px 12px;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: var(--paper);
  color: var(--ink-dim);
  font-size: 13px;
  min-height: 34px;
}
.dg-btn:hover { border-color: var(--indigo); color: var(--indigo); }
.dg-btn.selected {
  background: var(--indigo-soft);
  border-color: var(--indigo);
  color: var(--indigo);
  font-weight: 700;
}
.dg-btn:disabled { opacity: .4; cursor: default; }

.dg-note {
  flex: 1 1 100%;
  min-height: 1.7em;
  font-size: 13px;
  line-height: 1.7;
  color: var(--ink-dim);
}
.dg-note strong { color: var(--indigo-deep); }

.dg-range {
  flex: 1 1 150px;
  min-width: 120px;
  accent-color: var(--indigo);
}

.dg-legend {
  display: flex;
  flex-wrap: wrap;
  gap: 6px 16px;
  margin-top: 12px;
  font-size: 12px;
  color: var(--ink-dim);
}

.dg-legend span {
  display: inline-flex;
  align-items: center;
  gap: 6px;
}

.dg-swatch {
  width: 11px;
  height: 11px;
  border-radius: 3px;
  flex: none;
}

.diagram svg { display: block; max-width: 100%; height: auto; }
.diagram svg text { font-family: var(--sans); }

/* ── 測驗 ───────────────────────────────────────── */

.quiz {
  margin: 36px 0 0;
  padding: 22px 20px;
  background: var(--paper-raised);
  border: 1px solid var(--line);
  border-radius: var(--radius);
}

.quiz-head {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 12px;
  margin-bottom: 4px;
}

.quiz-title {
  margin: 0;
  font-family: var(--serif);
  font-size: 18px;
  font-weight: 700;
}

.quiz-score {
  font-family: var(--mono);
  font-size: 13px;
  color: var(--ink-faint);
  font-variant-numeric: tabular-nums;
}

.quiz-item {
  padding: 20px 0 4px;
  border-top: 1px solid var(--line-soft);
  margin-top: 16px;
}
.quiz-item:first-of-type { border-top: none; margin-top: 8px; }

.quiz-q {
  margin: 0 0 14px;
  font-weight: 600;
  line-height: 1.75;
  font-size: 16px;
}

.quiz-q-num {
  font-family: var(--mono);
  font-size: 12.5px;
  color: var(--indigo);
  margin-right: 8px;
}

.quiz-options {
  display: grid;
  gap: 8px;
}

.quiz-option {
  display: flex;
  gap: 10px;
  align-items: flex-start;
  width: 100%;
  padding: 11px 14px;
  text-align: left;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--paper);
  color: inherit;
  font-size: 15px;
  line-height: 1.7;
  transition: border-color .15s, background .15s;
}
.quiz-option:hover:not(:disabled) { border-color: var(--indigo); }
.quiz-option:disabled { cursor: default; }

.quiz-option-key {
  flex: none;
  font-family: var(--mono);
  font-size: 12.5px;
  color: var(--ink-faint);
  padding-top: 2px;
}

.quiz-option[data-state="correct"] {
  background: var(--teal-soft);
  border-color: var(--teal);
}
.quiz-option[data-state="correct"] .quiz-option-key { color: var(--teal); font-weight: 700; }

.quiz-option[data-state="wrong"] {
  background: var(--rose-soft);
  border-color: var(--rose);
}
.quiz-option[data-state="wrong"] .quiz-option-key { color: var(--rose); font-weight: 700; }

.quiz-option[data-state="muted"] { opacity: .55; }

.quiz-explain {
  margin: 12px 0 0;
  padding: 12px 14px;
  border-radius: 8px;
  background: var(--indigo-soft);
  font-size: 14.5px;
  line-height: 1.8;
}
.quiz-explain[hidden] { display: none; }

.quiz-verdict {
  font-weight: 700;
  margin-right: 6px;
}
.quiz-verdict[data-ok="1"] { color: var(--teal); }
.quiz-verdict[data-ok="0"] { color: var(--rose); }

/* ── 章末 ───────────────────────────────────────── */

.ch-foot {
  margin-top: 36px;
  padding-top: 24px;
  border-top: 1px solid var(--line);
}

.done-btn {
  width: 100%;
  padding: 14px;
  border: 1px solid var(--indigo);
  border-radius: var(--radius);
  background: var(--indigo);
  color: #FFF;
  font-size: 15.5px;
  font-weight: 600;
}
.done-btn:hover { background: var(--indigo-deep); }
.done-btn[data-done="1"] {
  background: var(--teal-soft);
  border-color: var(--teal);
  color: var(--teal);
}

.ch-pager {
  display: flex;
  gap: 10px;
  margin-top: 14px;
}

.pager-link {
  flex: 1;
  min-width: 0;
  padding: 12px 14px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--paper-raised);
  text-decoration: none;
  color: inherit;
  font-size: 13.5px;
  line-height: 1.5;
}
.pager-link:hover { border-color: var(--indigo); }
.pager-link[aria-disabled="true"] { opacity: .35; pointer-events: none; }
.pager-link.next { text-align: right; }

.pager-dir {
  display: block;
  font-size: 11.5px;
  letter-spacing: .1em;
  text-transform: uppercase;
  color: var(--ink-faint);
  margin-bottom: 3px;
}

.pager-name {
  display: block;
  font-weight: 600;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.loading,
.error-view {
  padding: 60px 0;
  text-align: center;
  color: var(--ink-dim);
}

/* ── 劃記系統（合併自 skill 提供的 annotation.css） ── */

.ch-nav .annotate-toggle {
  flex: none;
  padding: 5px 10px;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: var(--paper-raised);
  color: var(--indigo);
  font-size: 13px;
}

.ch-nav .annotate-toggle.active {
  background: var(--indigo);
  border-color: var(--indigo);
  color: #FFF;
}

.annotation-toolbar {
  position: sticky;
  top: var(--nav-h);
  z-index: 9;
  display: flex;
  gap: 6px;
  align-items: center;
  margin: -8px -22px 16px;
  padding: 8px 22px;
  overflow-x: auto;
  background: color-mix(in srgb, var(--paper) 94%, transparent);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--line);
}

.annotation-toolbar[hidden] { display: none; }

.annotation-tool,
.annotation-action {
  flex: none;
  min-width: 52px;
  min-height: 34px;
  padding: 6px 10px;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: var(--paper-raised);
  font-size: 13px;
  color: var(--ink);
}

.annotation-tool.selected {
  background: var(--indigo-soft);
  border-color: var(--indigo);
  color: var(--indigo);
  font-weight: 700;
}

.annotation-action { color: var(--ink-dim); }
.annotation-action:hover { border-color: var(--indigo); color: var(--indigo); }
.annotation-action:disabled { opacity: .4; cursor: default; }

body.annotation-active { overscroll-behavior: contain; }
body.annotation-active section.ch-section {
  user-select: none;
  -webkit-user-select: none;
}

section.ch-section.annotatable { position: relative; }
section.ch-section.annotatable > :not(.annotation-canvas) { position: relative; z-index: 1; }
section.ch-section .annotation-canvas {
  position: absolute;
  inset: 0;
  z-index: 2;
  width: 100%;
  height: 100%;
  pointer-events: none;
}

section.ch-section.annotating .annotation-canvas {
  pointer-events: auto;
  touch-action: none;
  cursor: crosshair;
}

/* ── 響應式 ─────────────────────────────────────── */

@media (max-width: 480px) {
  body { font-size: 16.5px; }
  .view { padding: 0 18px calc(60px + env(safe-area-inset-bottom)); }
  .ch-nav { margin: 0 -18px; padding: 10px 18px; }
  .annotation-toolbar { margin: -8px -18px 16px; padding: 8px 18px; }
  .home-title { font-size: 28px; }
  .ch-title { font-size: 25px; }
  .sec-title { font-size: 18.5px; }
  .quiz { padding: 18px 15px; }
  .analogy { padding: 17px 16px 15px; }
  .diagram { padding: 15px 13px; }
  .ch-link { grid-template-columns: 26px 1fr auto; gap: 10px; }
}

@media (min-width: 900px) {
  body { font-size: 17.5px; }
}