:root {
  --ink: #132238;
  --muted: #64748b;
  --paper: #f7fbff;
  --panel: #ffffff;
  --panel-soft: #eef6ff;
  --line: #d8e6f7;
  --blue: #2563eb;
  --blue-strong: #1d4ed8;
  --lavender: #ede9fe;
  --lavender-strong: #7c3aed;
  --green: #0f9f72;
  --yellow: #f7c948;
  --red: #d94841;
  --radius: 18px;
  --shadow: 0 18px 44px rgba(37, 99, 235, .12);
}

* {
  box-sizing: border-box;
  min-width: 0;
}

html { scroll-behavior: smooth; }

body {
  margin: 0;
  color: var(--ink);
  background:
    radial-gradient(circle at 12% 6%, rgba(37, 99, 235, .13), transparent 28rem),
    radial-gradient(circle at 86% 10%, rgba(124, 58, 237, .12), transparent 24rem),
    linear-gradient(90deg, rgba(37, 99, 235, .06) 1px, transparent 1px),
    linear-gradient(rgba(37, 99, 235, .06) 1px, transparent 1px),
    var(--paper);
  background-size: auto, auto, 32px 32px, 32px 32px, auto;
  font-family: "PingFang TC", "Noto Sans TC", "Microsoft JhengHei", system-ui, sans-serif;
  line-height: 1.7;
  overflow-x: hidden;
}

body::before {
  content: "";
  position: fixed;
  inset: 0;
  pointer-events: none;
  background: linear-gradient(180deg, rgba(255, 255, 255, .84), rgba(255, 255, 255, .46));
  z-index: -1;
}

a { color: var(--blue); }

main {
  width: min(1120px, calc(100% - 32px));
  margin: 0 auto;
  padding: 34px 0 72px;
}

.tools-index main { width: min(980px, calc(100% - 32px)); }

.tools-index header { display: block; }

.tools-index .grid { margin-top: 30px; }

.course-progress {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: 4px;
  z-index: 20;
  background: rgba(216, 230, 247, .85);
}

.course-progress span {
  display: block;
  width: 100%;
  height: 100%;
  background: linear-gradient(90deg, var(--blue), var(--lavender-strong));
  transform: scaleX(0);
  transform-origin: left;
}

@supports (animation-timeline: scroll()) {
  .course-progress span {
    animation: reading-progress linear both;
    animation-timeline: scroll(root);
  }
}

@keyframes reading-progress {
  from { transform: scaleX(0); }
  to { transform: scaleX(1); }
}

header,
.hero {
  position: relative;
  display: grid;
  grid-template-columns: minmax(0, 1.12fr) minmax(280px, .88fr);
  gap: 28px;
  align-items: end;
  padding: 34px;
  overflow: hidden;
  background:
    linear-gradient(135deg, rgba(255, 255, 255, .92), rgba(238, 246, 255, .84)),
    var(--panel);
  border: 1px solid rgba(37, 99, 235, .18);
  border-radius: 28px;
  box-shadow: var(--shadow);
}

header::after,
.hero::after {
  content: "";
  position: absolute;
  right: -90px;
  top: -120px;
  width: 280px;
  height: 280px;
  border-radius: 999px;
  background: rgba(124, 58, 237, .13);
}

.kicker {
  margin: 0 0 10px;
  color: var(--blue-strong);
  font-size: 14px;
  font-weight: 900;
  letter-spacing: .08em;
}

h1 {
  margin: 0;
  max-width: 860px;
  font-size: clamp(36px, 5vw, 68px);
  line-height: 1.08;
  letter-spacing: 0;
  overflow-wrap: anywhere;
}

.hero p,
.intro {
  margin: 18px 0 0;
  max-width: 660px;
  color: var(--muted);
  font-size: 20px;
}

.stamp {
  position: relative;
  z-index: 1;
  justify-self: end;
  width: min(100%, 330px);
  padding: 22px;
  color: var(--ink);
  background: linear-gradient(150deg, #ffffff, #eef6ff 58%, #f3f0ff);
  border: 1px solid rgba(37, 99, 235, .22);
  border-radius: 22px;
  box-shadow: 0 18px 38px rgba(37, 99, 235, .14);
}

.stamp strong {
  display: block;
  margin-bottom: 10px;
  font-size: 28px;
  line-height: 1.1;
}

.stamp span {
  display: block;
  color: var(--muted);
  font-size: 15px;
}

section {
  padding: 34px 0;
  border-bottom: 1px solid var(--line);
}

h2 {
  margin: 0 0 18px;
  font-size: clamp(25px, 3vw, 36px);
  line-height: 1.22;
  letter-spacing: 0;
}

h3 {
  margin: 0 0 8px;
  font-size: 20px;
  line-height: 1.28;
}

p { margin: 0; }

p,
li,
figcaption,
.course-overview span {
  overflow-wrap: anywhere;
  word-break: break-all;
  line-break: anywhere;
}

ol,
ul {
  margin: 10px 0 0;
  padding-left: 22px;
}

.grid,
.lesson-nav,
.visual-grid,
.course-overview,
.cheat-grid,
.quiz-grid {
  display: grid;
  grid-template-columns: repeat(12, minmax(0, 1fr));
  gap: 16px;
}

.grid > *,
.visual-grid > *,
.cheat-grid > * { grid-column: span 4; }

.grid.two > * { grid-column: span 6; }

.card,
.step,
.image-card,
.info-card,
.warning-card,
.tip-card,
.summary-card,
.quiz-card,
.prompt-shell,
.lesson-nav a,
.tools-index .card {
  background: rgba(255, 255, 255, .94);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: 0 10px 30px rgba(37, 99, 235, .08);
}

.card,
.info-card,
.warning-card,
.tip-card,
.summary-card,
.quiz-card {
  min-height: 154px;
  padding: 20px;
}

.card p,
.card li,
.step p,
.step li,
.info-card p,
.warning-card p,
.tip-card p,
.summary-card p {
  color: var(--muted);
  font-size: 15px;
}

.card a {
  color: var(--blue);
  font-weight: 850;
  text-decoration-thickness: 2px;
  text-underline-offset: 3px;
}

.course-overview > * {
  grid-column: span 4;
  padding: 18px;
  background: rgba(238, 246, 255, .88);
  border: 1px solid var(--line);
  border-radius: var(--radius);
}

.course-overview strong {
  display: block;
  color: var(--blue-strong);
  font-size: 14px;
}

.course-overview span {
  display: block;
  margin-top: 6px;
  color: var(--muted);
}

.course-map {
  display: grid;
  grid-template-columns: repeat(6, minmax(0, 1fr));
  gap: 10px;
  padding: 18px 0 4px;
}

.course-map span,
.course-map a {
  display: block;
  padding: 12px;
  color: var(--muted);
  background: rgba(255, 255, 255, .76);
  border: 1px solid var(--line);
  border-radius: 14px;
  font-size: 14px;
  font-weight: 850;
  text-align: center;
  text-decoration: none;
}

.course-map .is-current {
  color: #ffffff;
  background: var(--blue);
  border-color: var(--blue);
}

.timeline {
  display: grid;
  gap: 14px;
}

.step {
  display: grid;
  grid-template-columns: 104px 1fr;
  gap: 18px;
  align-items: stretch;
  overflow: hidden;
}

.time {
  display: grid;
  place-items: center;
  padding: 16px;
  color: #ffffff;
  background: linear-gradient(135deg, var(--blue), var(--lavender-strong));
  font-weight: 900;
  text-align: center;
}

.step-body { padding: 18px 20px 18px 0; }

.step-list {
  display: grid;
  gap: 6px;
  padding-left: 20px;
  color: var(--muted);
  font-size: 15px;
}

.step-list strong { color: var(--ink); }

.prompt {
  margin: 0;
  padding: 18px;
  color: #15304f;
  background: #f8fbff;
  border: 1px solid #c9dcf6;
  border-radius: 14px;
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-size: 14px;
  line-height: 1.62;
  white-space: pre-wrap;
  overflow-x: auto;
}

.prompt-shell { margin-top: 12px; padding: 10px; }

.prompt-toolbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 10px;
  margin-bottom: 10px;
  color: var(--muted);
  font-size: 13px;
  font-weight: 800;
}

.copy-button,
.quiz-card button {
  border: 0;
  border-radius: 999px;
  padding: 8px 13px;
  color: #ffffff;
  background: var(--blue);
  font: inherit;
  font-size: 13px;
  font-weight: 850;
  cursor: pointer;
}

.copy-button:focus-visible,
.quiz-card button:focus-visible,
.lesson-nav a:focus-visible,
summary:focus-visible {
  outline: 3px solid rgba(37, 99, 235, .28);
  outline-offset: 3px;
}

.copy-button:active,
.quiz-card button:active { transform: translateY(1px); }

.checklist {
  columns: 2;
  column-gap: 26px;
  padding-left: 0;
  list-style: none;
}

.checklist li {
  break-inside: avoid;
  display: flex;
  gap: 10px;
  align-items: flex-start;
  margin: 0 0 12px;
  color: var(--muted);
}

.checklist input {
  width: 18px;
  height: 18px;
  margin-top: 4px;
  accent-color: var(--blue);
}

.checklist li.is-done span {
  color: #3d5a78;
  text-decoration: line-through;
}

.image-card {
  overflow: hidden;
}

.image-card img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 16 / 9;
  background: #eef6ff;
}

.image-card figcaption {
  padding: 14px 16px 16px;
  color: var(--muted);
  font-size: 14px;
}

.info-card { background: #eef6ff; }
.tip-card { background: #f3f0ff; }
.warning-card { background: #fff8e6; border-color: #f4d179; }
.summary-card { background: linear-gradient(135deg, #eef6ff, #f3f0ff); }

.assessment-table {
  width: 100%;
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  border-spacing: 0;
  background: rgba(255, 255, 255, .94);
  box-shadow: 0 10px 30px rgba(37, 99, 235, .08);
}

.assessment-table th,
.assessment-table td {
  padding: 14px;
  border-bottom: 1px solid var(--line);
  color: var(--muted);
  text-align: left;
  vertical-align: top;
}

.assessment-table th {
  color: var(--ink);
  background: #eef6ff;
}

.assessment-table tr:last-child th,
.assessment-table tr:last-child td { border-bottom: 0; }

.quiz-card { grid-column: span 6; }

.quiz-card p { color: var(--muted); }

.quiz-options {
  display: grid;
  gap: 8px;
  margin-top: 12px;
}

.quiz-card label {
  display: flex;
  gap: 8px;
  align-items: flex-start;
  padding: 10px;
  background: #f8fbff;
  border: 1px solid var(--line);
  border-radius: 12px;
  cursor: pointer;
}

.quiz-result {
  min-height: 24px;
  margin-top: 12px;
  color: var(--blue-strong);
  font-weight: 850;
}

details {
  margin-top: 12px;
  padding: 16px 18px;
  background: #ffffff;
  border: 1px solid var(--line);
  border-radius: var(--radius);
}

summary {
  color: var(--ink);
  cursor: pointer;
  font-weight: 900;
}

details p {
  margin-top: 10px;
  color: var(--muted);
}

[data-tip] {
  position: relative;
  color: var(--blue-strong);
  border-bottom: 1px dotted rgba(37, 99, 235, .55);
  cursor: help;
}

[data-tip]::after {
  content: attr(data-tip);
  position: absolute;
  left: 0;
  bottom: calc(100% + 8px);
  width: min(260px, 80vw);
  padding: 10px 12px;
  color: #ffffff;
  background: #1e3a5f;
  border-radius: 12px;
  box-shadow: 0 14px 28px rgba(19, 34, 56, .18);
  font-size: 13px;
  line-height: 1.45;
  opacity: 0;
  pointer-events: none;
  transform: translateY(6px);
  transition: opacity .18s ease, transform .18s ease;
  z-index: 10;
}

[data-tip]:hover::after,
[data-tip]:focus::after {
  opacity: 1;
  transform: translateY(0);
}

.lesson-nav a,
.tools-index .card {
  display: block;
  grid-column: span 4;
  padding: 18px;
  color: var(--ink);
  text-decoration: none;
  font-weight: 850;
  transition: transform .18s ease, border-color .18s ease, box-shadow .18s ease;
}

.lesson-nav a:hover,
.tools-index .card:hover {
  border-color: rgba(37, 99, 235, .48);
  box-shadow: 0 18px 40px rgba(37, 99, 235, .16);
  transform: translateY(-2px);
}

.tag {
  align-self: end;
  width: max-content;
  padding: 5px 10px;
  color: #ffffff;
  background: var(--blue);
  border-radius: 999px;
  font-size: 13px;
  font-weight: 850;
}

footer {
  padding-top: 26px;
  color: var(--muted);
  font-size: 14px;
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *,
  *::before,
  *::after {
    animation-duration: .01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: .01ms !important;
  }
}

@media (max-width: 860px) {
  main {
    width: 100%;
    max-width: 100%;
    padding: 20px 10px 72px;
  }
  header,
  .hero,
  .step { grid-template-columns: 1fr; padding: 22px; }
  h1 {
    font-size: clamp(28px, 8vw, 34px);
    line-height: 1.14;
    word-break: break-all;
  }
  header > div,
  .hero > div,
  .stamp {
    max-width: 100%;
  }
  .hero p,
  .intro {
    max-width: 300px;
    font-size: 17px;
    word-break: break-all;
  }
  .grid,
  .lesson-nav,
  .visual-grid,
  .course-overview,
  .course-map,
  .cheat-grid,
  .quiz-grid {
    display: block;
  }
  .grid > *,
  .lesson-nav > *,
  .visual-grid > *,
  .course-overview > *,
  .course-map > *,
  .cheat-grid > *,
  .quiz-grid > * {
    margin-bottom: 16px;
  }
  .stamp { justify-self: stretch; }
  .course-overview span {
    font-size: 15px;
    line-height: 1.55;
  }
  .step-body { padding: 18px; }
  .time { place-items: start; }
  .grid > *,
  .grid.two > *,
  .visual-grid > *,
  .course-overview > *,
  .cheat-grid > *,
  .quiz-card,
  .lesson-nav a,
  .tools-index .card {
    grid-column: 1 / -1;
  }
  .checklist { columns: 1; }
}

@media print {
  body { background: white; }
  body::before,
  .course-progress,
  .copy-button { display: none; }
  main { width: 100%; padding: 0; }
  header,
  .hero,
  .card,
  .step,
  .image-card,
  .prompt-shell { box-shadow: none; break-inside: avoid; }
}