:root {
  color-scheme: light;
  --bg: #f6fbf9;
  --surface: #ffffff;
  --surface-soft: #edf8f5;
  --ink: #17332f;
  --muted: #5d716c;
  --line: #cfe4de;
  --brand: #0f8f83;
  --brand-strong: #0a6d65;
  --brand-soft: #d7f4ee;
  --accent: #bf315f;
  --warn: #856404;
  --warn-bg: #fff6d8;
  --shadow: 0 14px 38px rgba(23, 51, 47, 0.09);
  --radius: 8px;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  line-height: 1.6;
  overflow-x: hidden;
}

h1,
h2,
h3,
p,
li,
strong,
span {
  min-width: 0;
  overflow-wrap: anywhere;
}

button,
a {
  -webkit-tap-highlight-color: transparent;
}

button {
  border: 0;
  border-radius: var(--radius);
  cursor: pointer;
  font: inherit;
}

a {
  color: inherit;
  text-decoration: none;
}

main {
  width: min(1180px, calc(100vw - 32px));
  margin: 0 auto;
}

.skip-link {
  position: absolute;
  left: 16px;
  top: -48px;
  z-index: 10;
  padding: 10px 14px;
  background: var(--ink);
  color: #fff;
  border-radius: var(--radius);
}

.skip-link:focus {
  top: 12px;
}

.topbar {
  position: sticky;
  top: 0;
  z-index: 5;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  padding: 16px clamp(16px, 4vw, 40px);
  background: rgba(246, 251, 249, 0.92);
  border-bottom: 1px solid var(--line);
  backdrop-filter: blur(14px);
}

.topbar > div:first-of-type {
  min-width: 0;
}

.topbar h1,
.overview h2,
.lesson h2,
.section-head h2 {
  margin: 0;
  line-height: 1.15;
}

.topbar h1 {
  font-size: clamp(20px, 3vw, 30px);
}

.topbar__status {
  display: grid;
  min-width: 86px;
  padding: 8px 10px;
  text-align: center;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

.topbar__status span:first-child {
  font-size: 20px;
  font-weight: 800;
  color: var(--brand-strong);
}

.topbar__status span:last-child {
  font-size: 12px;
  color: var(--muted);
}

.eyebrow,
.panel__label {
  margin: 0 0 6px;
  color: var(--brand-strong);
  font-size: 12px;
  font-weight: 800;
}

.overview {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 280px;
  gap: 24px;
  align-items: stretch;
  padding: 30px 0 18px;
}

.overview__copy,
.overview__meter,
.source-note,
.architecture,
.lesson,
.simulator,
.playbook,
.memory,
.glossary {
  min-width: 0;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

.overview__copy > *,
.source-note > *,
.architecture > *,
.lesson__head > *,
.section-head > *,
.panel > *,
.scenario-card > *,
.simulator-output > *,
.playbook-card > *,
.layer-card > *,
.result-column > *,
.term > * {
  min-width: 0;
}

.overview__copy {
  padding: clamp(22px, 4vw, 38px);
}

.overview__copy h2 {
  margin-bottom: 12px;
  font-size: clamp(28px, 6vw, 48px);
  max-width: 760px;
}

.overview__copy p {
  max-width: 760px;
  margin: 0;
  color: var(--muted);
  font-size: 17px;
}

.quick-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 24px;
}

.primary-action,
.secondary-action,
.lesson-actions button,
.complete-button,
.quiz__head button {
  min-height: 42px;
  padding: 10px 14px;
  font-weight: 800;
}

.primary-action,
.complete-button {
  background: var(--brand);
  color: #fff;
}

.secondary-action,
.lesson-actions button,
.quiz__head button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  background: var(--surface-soft);
  border: 1px solid var(--line);
  color: var(--ink);
}

.overview__meter {
  display: grid;
  place-items: center;
  padding: 24px;
  text-align: center;
}

.overview__meter p {
  margin: 12px 0 0;
  color: var(--muted);
  font-size: 14px;
}

.meter {
  display: grid;
  width: 158px;
  height: 158px;
  place-items: center;
  border-radius: 50%;
  background:
    radial-gradient(circle at center, #fff 0 57%, transparent 58%),
    conic-gradient(var(--brand) var(--progress, 0%), var(--brand-soft) 0);
}

.meter span {
  font-size: 28px;
  font-weight: 900;
}

.source-note {
  display: grid;
  grid-template-columns: auto 1fr auto 1fr;
  gap: 8px 12px;
  padding: 14px 16px;
  margin: 0 0 18px;
  color: var(--muted);
  font-size: 14px;
}

.source-note strong {
  color: var(--ink);
}

.lesson-tabs {
  display: grid;
  grid-template-columns: repeat(10, minmax(120px, 1fr));
  gap: 8px;
  margin: 0 0 14px;
  overflow-x: auto;
  padding-bottom: 2px;
}

.lesson-tabs button {
  min-width: 120px;
  padding: 12px 10px;
  background: var(--surface);
  border: 1px solid var(--line);
  color: var(--muted);
  text-align: left;
}

.lesson-tabs button[aria-selected="true"] {
  background: var(--brand-soft);
  border-color: var(--brand);
  color: var(--ink);
}

.lesson-tabs span {
  display: block;
  font-size: 12px;
}

.lesson-tabs strong {
  display: block;
  margin-top: 4px;
  line-height: 1.25;
}

.lesson,
.architecture,
.simulator,
.playbook,
.memory,
.glossary {
  padding: clamp(18px, 4vw, 30px);
  margin: 0 0 22px;
}

.architecture-rail {
  display: grid;
  grid-template-columns: repeat(8, minmax(150px, 1fr));
  gap: 10px;
  margin-top: 22px;
  overflow-x: auto;
  padding-bottom: 2px;
}

.arch-step {
  min-height: 180px;
  padding: 16px;
  background: var(--surface-soft);
  border: 1px solid var(--line);
  border-radius: var(--radius);
}

.arch-step span,
.term span {
  display: inline-flex;
  margin-bottom: 10px;
  padding: 3px 8px;
  border-radius: 999px;
  background: var(--brand-soft);
  color: var(--brand-strong);
  font-size: 12px;
  font-weight: 900;
}

.arch-step strong,
.layer-card strong {
  display: block;
  line-height: 1.25;
}

.arch-step p,
.layer-card p {
  margin: 8px 0 0;
  color: var(--muted);
  font-size: 14px;
}

.layer-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 10px;
  margin-top: 12px;
}

.layer-card {
  padding: 16px;
  background: #fff;
  border: 1px solid var(--line);
  border-radius: var(--radius);
}

.layer-card h3 {
  margin: 0 0 8px;
}

.layer-card strong {
  margin-top: 12px;
  color: var(--brand-strong);
}

.lesson__head,
.section-head,
.quiz__head {
  display: flex;
  align-items: start;
  justify-content: space-between;
  gap: 18px;
}

.lesson__head h2,
.section-head h2 {
  font-size: clamp(24px, 4vw, 36px);
}

.lesson__head p,
.section-head p {
  margin: 8px 0 0;
  max-width: 720px;
  color: var(--muted);
}

.complete-button.is-done {
  background: var(--ink);
}

.lesson-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.35fr) minmax(260px, 0.65fr);
  gap: 14px;
  margin-top: 22px;
}

.detail-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.1fr) minmax(0, 0.95fr) minmax(0, 0.95fr);
  gap: 14px;
  margin-top: 14px;
}

.panel,
.scenario-card,
.simulator-output,
.flashcard,
.quiz {
  min-width: 0;
  background: var(--surface-soft);
  border: 1px solid var(--line);
  border-radius: var(--radius);
}

.panel {
  padding: 18px;
}

.panel h3,
.scenario-card h3,
.flashcard h3,
.quiz h3 {
  margin: 0 0 10px;
  line-height: 1.25;
}

.panel p {
  margin: 0;
  color: var(--muted);
}

.panel ul {
  margin: 0;
  padding-left: 18px;
}

.panel li + li {
  margin-top: 8px;
}

.flow-board {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 10px;
  margin-top: 14px;
}

.flow-step {
  min-height: 142px;
  padding: 16px;
  background: #fff;
  border: 1px solid var(--line);
  border-radius: var(--radius);
}

.flow-step span {
  display: inline-flex;
  width: 28px;
  height: 28px;
  align-items: center;
  justify-content: center;
  margin-bottom: 10px;
  border-radius: 50%;
  background: var(--brand);
  color: #fff;
  font-size: 13px;
  font-weight: 900;
}

.flow-step strong {
  display: block;
  line-height: 1.25;
}

.flow-step p {
  margin: 8px 0 0;
  color: var(--muted);
  font-size: 14px;
}

.evidence-list {
  display: grid;
  gap: 10px;
}

.evidence-item {
  padding: 12px;
  background: #fff;
  border: 1px solid var(--line);
  border-radius: var(--radius);
}

.evidence-item strong {
  display: block;
  margin-bottom: 5px;
}

.evidence-item p {
  margin: 0;
  color: var(--muted);
  font-size: 14px;
}

.scenario-card {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(240px, 0.55fr);
  gap: 18px;
  margin-top: 14px;
  padding: 18px;
}

.scenario-card p {
  margin: 0;
}

.scenario-card p:not(.panel__label) {
  color: var(--muted);
}

.lesson-actions {
  display: flex;
  justify-content: space-between;
  gap: 10px;
  margin-top: 16px;
}

.simulator-layout {
  display: grid;
  grid-template-columns: 270px minmax(0, 1fr);
  gap: 14px;
  margin-top: 20px;
}

.scenario-list {
  display: grid;
  gap: 8px;
}

.scenario-list button {
  padding: 12px;
  background: #fff;
  border: 1px solid var(--line);
  color: var(--ink);
  text-align: left;
}

.scenario-list button[aria-pressed="true"] {
  background: var(--brand-soft);
  border-color: var(--brand);
}

.scenario-list strong,
.scenario-list span {
  display: block;
}

.scenario-list span {
  margin-top: 3px;
  color: var(--muted);
  font-size: 13px;
}

.simulator-output {
  padding: 18px;
}

.simulator-output h3 {
  margin: 0 0 8px;
  font-size: 24px;
}

.simulator-output p {
  margin: 0 0 12px;
  color: var(--muted);
}

.state-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 8px;
  margin: 12px 0;
}

.state-pill {
  padding: 10px;
  background: #fff;
  border: 1px solid var(--line);
  border-radius: var(--radius);
}

.state-pill span {
  display: block;
  color: var(--muted);
  font-size: 12px;
}

.state-pill strong {
  display: block;
}

.result-columns {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 10px;
}

.result-column {
  padding: 14px;
  background: #fff;
  border: 1px solid var(--line);
  border-radius: var(--radius);
}

.result-column h4 {
  margin: 0 0 8px;
}

.result-column ul {
  margin: 0;
  padding-left: 18px;
}

.mentor-note {
  margin-top: 12px;
  padding: 12px;
  background: var(--warn-bg);
  border: 1px solid #f0dc8a;
  border-radius: var(--radius);
  color: var(--warn);
}

.playbook-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 12px;
  margin-top: 20px;
}

.playbook-card {
  padding: 16px;
  background: var(--surface-soft);
  border: 1px solid var(--line);
  border-radius: var(--radius);
}

.playbook-card h3 {
  margin: 0 0 10px;
}

.playbook-card ul {
  margin: 0 0 12px;
  padding-left: 18px;
}

.playbook-card strong {
  display: block;
  color: var(--brand-strong);
}

.memory-grid {
  display: grid;
  grid-template-columns: minmax(0, 0.85fr) minmax(0, 1.15fr);
  gap: 14px;
  margin-top: 20px;
}

.flashcard {
  min-height: 300px;
  padding: 22px;
  outline: none;
  transition: transform 160ms ease, background 160ms ease;
}

.flashcard:focus {
  box-shadow: 0 0 0 3px rgba(15, 143, 131, 0.24);
}

.flashcard.is-answer {
  background: #fff;
}

.flashcard h3 {
  font-size: 24px;
}

.flashcard p:not(.panel__label) {
  color: var(--muted);
}

.flashcard span {
  display: inline-block;
  margin-top: 20px;
  color: var(--brand-strong);
  font-weight: 800;
}

.quiz {
  padding: 18px;
}

.quiz h3 {
  font-size: 22px;
}

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

.quiz-options button {
  padding: 12px;
  background: #fff;
  border: 1px solid var(--line);
  color: var(--ink);
  text-align: left;
}

.quiz-options button.is-correct {
  border-color: var(--brand);
  background: var(--brand-soft);
}

.quiz-options button.is-wrong {
  border-color: var(--accent);
  background: #fdeaf1;
}

.quiz-feedback {
  min-height: 28px;
  margin: 12px 0 0;
  color: var(--muted);
  font-weight: 700;
}

.glossary-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 10px;
  margin-top: 20px;
}

.glossary-tools {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 18px;
}

.glossary-tools button {
  padding: 8px 12px;
  background: var(--surface-soft);
  border: 1px solid var(--line);
  color: var(--ink);
  font-weight: 800;
}

.glossary-tools button[aria-pressed="true"] {
  background: var(--brand);
  color: #fff;
  border-color: var(--brand);
}

.term {
  padding: 14px;
  background: var(--surface-soft);
  border: 1px solid var(--line);
  border-radius: var(--radius);
}

.term strong {
  display: block;
  margin-bottom: 6px;
}

.term p {
  margin: 0;
  color: var(--muted);
  font-size: 14px;
}

code {
  padding: 2px 5px;
  background: rgba(15, 143, 131, 0.1);
  border: 1px solid rgba(15, 143, 131, 0.14);
  border-radius: 5px;
  color: var(--brand-strong);
  font-family: "SFMono-Regular", Consolas, "Liberation Mono", monospace;
  font-size: 0.92em;
  overflow-wrap: anywhere;
}

.topic-hero {
  margin: 30px 0 14px;
  padding: clamp(24px, 5vw, 44px);
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

.topic-hero h2 {
  max-width: 850px;
  margin: 0 0 14px;
  font-size: clamp(30px, 5vw, 52px);
  line-height: 1.08;
}

.topic-hero p:not(.eyebrow) {
  max-width: 820px;
  margin: 0;
  color: var(--muted);
  font-size: 17px;
}

.topic-nav {
  display: flex;
  gap: 8px;
  margin: 0 0 18px;
  overflow-x: auto;
  padding-bottom: 4px;
}

.topic-nav a {
  flex: 0 0 auto;
  padding: 9px 12px;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  color: var(--muted);
  font-size: 14px;
  font-weight: 800;
}

.topic-nav a:focus,
.topic-nav a:hover {
  background: var(--brand-soft);
  color: var(--ink);
}

.topic-section {
  margin: 0 0 22px;
  padding: clamp(18px, 4vw, 30px);
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

.compare-grid,
.flow-columns,
.qa-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 14px;
  margin-top: 20px;
}

.compare-card,
.flow-columns article,
.qa-grid article,
.decision-path article {
  min-width: 0;
  padding: 18px;
  background: var(--surface-soft);
  border: 1px solid var(--line);
  border-radius: var(--radius);
}

.compare-card h3,
.flow-columns h3,
.qa-grid h3,
.decision-path h3 {
  margin: 0 0 10px;
  line-height: 1.25;
}

.compare-card p:not(.panel__label),
.qa-grid p,
.decision-path p {
  margin: 0;
  color: var(--muted);
}

.compare-card p + ul,
.flow-columns ol,
.qa-grid ul {
  margin: 12px 0 0;
  padding-left: 20px;
}

.compare-card li + li,
.flow-columns li + li,
.qa-grid li + li {
  margin-top: 7px;
}

.sequence {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 10px;
  margin-top: 20px;
}

.sequence article {
  min-width: 0;
  padding: 16px;
  background: var(--surface-soft);
  border: 1px solid var(--line);
  border-radius: var(--radius);
}

.sequence span,
.decision-path span {
  display: inline-flex;
  width: 30px;
  height: 30px;
  align-items: center;
  justify-content: center;
  margin-bottom: 10px;
  border-radius: 50%;
  background: var(--brand);
  color: #fff;
  font-size: 13px;
  font-weight: 900;
}

.sequence strong {
  display: block;
  line-height: 1.25;
}

.sequence p {
  margin: 8px 0 0;
  color: var(--muted);
  font-size: 14px;
}

.table-wrap {
  margin-top: 16px;
  overflow-x: auto;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: #fff;
}

table {
  width: 100%;
  min-width: 720px;
  border-collapse: collapse;
}

th,
td {
  padding: 12px 14px;
  border-bottom: 1px solid var(--line);
  text-align: left;
  vertical-align: top;
}

th {
  background: var(--surface-soft);
  color: var(--ink);
  font-size: 14px;
}

td {
  color: var(--muted);
  font-size: 14px;
}

tbody tr:last-child td {
  border-bottom: 0;
}

.note-box,
.warning-box,
.summary-box {
  display: flex;
  gap: 10px;
  align-items: start;
  margin-top: 14px;
  padding: 13px 14px;
  border-radius: var(--radius);
}

.note-box,
.summary-box {
  background: var(--brand-soft);
  border: 1px solid var(--line);
}

.warning-box {
  background: var(--warn-bg);
  border: 1px solid #f0dc8a;
  color: var(--warn);
}

.note-box span,
.summary-box span {
  color: var(--muted);
}

.warning-box span {
  color: var(--warn);
}

.flow-columns article {
  background: #fff;
}

.flow-columns ol {
  color: var(--muted);
}

.qa-grid article {
  background: #fff;
}

.qa-grid p + p {
  margin-top: 10px;
}

.decision-path {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 10px;
  margin-top: 20px;
}

.footer {
  width: min(1180px, calc(100vw - 32px));
  margin: 0 auto;
  padding: 8px 0 36px;
  color: var(--muted);
  font-size: 14px;
}

@media (max-width: 980px) {
  .overview,
  .lesson-grid,
  .detail-grid,
  .scenario-card,
  .simulator-layout,
  .memory-grid,
  .compare-grid,
  .flow-columns,
  .qa-grid {
    grid-template-columns: 1fr;
  }

  .overview__meter {
    display: none;
  }

  .flow-board,
  .layer-grid,
  .playbook-grid,
  .glossary-grid,
  .sequence,
  .decision-path {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .result-columns,
  .state-grid {
    grid-template-columns: 1fr;
  }

  .source-note {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 640px) {
  main,
  .footer {
    width: calc(100vw - 20px);
    max-width: 1180px;
  }

  .topbar {
    align-items: start;
    flex-wrap: wrap;
    gap: 8px;
    padding: 12px 10px;
  }

  .topbar h1 {
    font-size: 18px;
  }

  .topbar__status {
    min-width: 0;
    flex: 1 1 100%;
    grid-template-columns: auto auto;
    place-items: center;
    justify-content: start;
    gap: 8px;
    padding: 6px 8px;
  }

  .overview {
    padding-top: 12px;
  }

  .overview__copy,
  .architecture,
  .lesson,
  .simulator,
  .playbook,
  .memory,
  .glossary,
  .topic-section {
    padding: 16px;
  }

  .overview__copy h2 {
    font-size: 30px;
  }

  .topic-hero h2 {
    font-size: 28px;
    line-height: 1.12;
  }

  .topic-hero p:not(.eyebrow) {
    font-size: 16px;
  }

  .quick-actions,
  .lesson-actions,
  .lesson__head,
  .section-head {
    align-items: stretch;
    flex-direction: column;
  }

  .primary-action,
  .secondary-action,
  .complete-button,
  .lesson-actions button {
    width: 100%;
  }

  .lesson-tabs {
    grid-template-columns: repeat(10, 132px);
  }

  .flow-board,
  .layer-grid,
  .playbook-grid,
  .glossary-grid,
  .sequence,
  .decision-path {
    grid-template-columns: 1fr;
  }

  .flow-step {
    min-height: auto;
  }

  .topic-hero {
    margin-top: 12px;
    padding: 18px;
  }

  .topic-nav {
    margin-bottom: 12px;
  }

  .topic-nav a {
    padding: 8px 10px;
  }

  .note-box,
  .warning-box,
  .summary-box {
    flex-direction: column;
  }
}