:root {
  color-scheme: light;
  --paper: #f4f1ea;
  --surface: #fffaf1;
  --surface-2: #ebe5d8;
  --ink: #121822;
  --muted: #667085;
  --line: #d9d1c2;
  --blue: #2454a6;
  --blue-deep: #0f2f5f;
  --teal: #187b72;
  --gold: #b87521;
  --red: #b64b40;
  --green: #2f7a4f;
  --shadow: 0 20px 50px rgba(18, 24, 34, 0.12);
  --sans: "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB", "Segoe UI", Arial, sans-serif;
  --serif: Georgia, "Times New Roman", "Songti SC", serif;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  min-height: 100vh;
  background:
    linear-gradient(90deg, rgba(36, 84, 166, 0.08) 1px, transparent 1px),
    linear-gradient(0deg, rgba(36, 84, 166, 0.06) 1px, transparent 1px),
    var(--paper);
  background-size: 44px 44px;
  color: var(--ink);
  font-family: var(--sans);
}

button,
input {
  font: inherit;
}

button {
  cursor: pointer;
}

.course-app {
  display: grid;
  grid-template-columns: 312px minmax(0, 1fr);
  min-height: 100vh;
}

.sidebar {
  position: sticky;
  top: 0;
  height: 100vh;
  overflow: auto;
  padding: 24px 18px;
  background: #111925;
  color: #f9f3e8;
  border-right: 1px solid rgba(255, 255, 255, 0.08);
}

.brand {
  display: flex;
  align-items: center;
  gap: 12px;
  color: inherit;
  text-decoration: none;
  padding-bottom: 22px;
  border-bottom: 1px solid rgba(255, 255, 255, 0.12);
}

.brand-symbol {
  display: grid;
  place-items: center;
  width: 46px;
  height: 46px;
  border: 1px solid rgba(255, 255, 255, 0.24);
  background: #f5c46b;
  color: #111925;
  font-weight: 850;
  font-size: 15px;
}

.brand strong {
  display: block;
  font-size: 15px;
  line-height: 1.3;
}

.brand small {
  display: block;
  margin-top: 3px;
  color: rgba(249, 243, 232, 0.62);
  font-size: 12px;
}

.course-meta {
  padding: 24px 0 18px;
}

.course-meta p,
.panel-kicker {
  margin: 0 0 10px;
  color: var(--gold);
  font-size: 11px;
  font-weight: 800;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

.course-meta h1 {
  margin: 0;
  font-family: var(--serif);
  font-size: 28px;
  line-height: 1.18;
}

.course-meta dl {
  margin: 24px 0 0;
}

.course-meta div {
  padding: 12px 0;
  border-top: 1px solid rgba(255, 255, 255, 0.1);
}

.course-meta dt {
  float: left;
  width: 42px;
  color: rgba(249, 243, 232, 0.55);
  font-size: 12px;
}

.course-meta dd {
  margin: 0 0 0 52px;
  color: rgba(249, 243, 232, 0.88);
  font-size: 12px;
  line-height: 1.55;
}

.module-nav {
  display: grid;
  gap: 7px;
  padding-bottom: 24px;
}

.nav-item {
  display: grid;
  grid-template-columns: 34px minmax(0, 1fr);
  align-items: center;
  gap: 10px;
  width: 100%;
  min-height: 48px;
  padding: 8px 10px;
  border: 1px solid transparent;
  background: transparent;
  color: rgba(249, 243, 232, 0.74);
  text-align: left;
}

.nav-item:hover,
.nav-item.is-active {
  border-color: rgba(245, 196, 107, 0.5);
  background: rgba(245, 196, 107, 0.08);
  color: #fffaf1;
}

.nav-index {
  display: grid;
  place-items: center;
  width: 32px;
  height: 32px;
  background: rgba(255, 255, 255, 0.08);
  color: #f5c46b;
  font-family: var(--serif);
  font-weight: 800;
}

.nav-item.is-active .nav-index {
  background: #f5c46b;
  color: #111925;
}

.nav-item strong {
  display: block;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
  font-size: 12px;
}

.nav-item span:last-child {
  display: block;
  margin-top: 2px;
  overflow: hidden;
  color: rgba(249, 243, 232, 0.52);
  font-size: 11px;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.workspace {
  min-width: 0;
  padding: 24px;
}

.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
  margin-bottom: 18px;
}

.progress-wrap {
  display: flex;
  align-items: center;
  gap: 12px;
  min-width: 280px;
}

#progressLabel {
  min-width: 58px;
  color: var(--blue-deep);
  font-family: var(--serif);
  font-size: 14px;
  font-weight: 800;
}

.progress-track {
  width: min(360px, 42vw);
  height: 7px;
  overflow: hidden;
  background: rgba(18, 24, 34, 0.12);
}

.progress-track i {
  display: block;
  width: 0;
  height: 100%;
  background: var(--blue);
  transition: width 0.25s ease;
}

.top-actions,
.dialog-actions {
  display: flex;
  align-items: center;
  gap: 8px;
}

.icon-btn,
.ghost-btn,
.primary-btn {
  border: 1px solid var(--line);
  background: var(--surface);
  color: var(--ink);
}

.icon-btn {
  display: grid;
  place-items: center;
  width: 38px;
  height: 38px;
  font-size: 18px;
  line-height: 1;
}

.icon-btn:hover,
.ghost-btn:hover {
  border-color: var(--blue);
  color: var(--blue);
}

.primary-btn,
.ghost-btn {
  min-height: 40px;
  padding: 0 14px;
  font-size: 13px;
  font-weight: 750;
}

.primary-btn {
  border-color: var(--blue);
  background: var(--blue);
  color: #fff;
}

.stage {
  display: grid;
  grid-template-columns: minmax(680px, 1fr) 300px;
  gap: 18px;
  align-items: start;
}

.slide {
  position: relative;
  min-height: 690px;
  overflow: hidden;
  background: var(--surface);
  border: 1px solid var(--line);
  box-shadow: var(--shadow);
}

.slide-inner {
  min-height: 690px;
  padding: 46px 54px 40px;
}

.slide-number {
  position: absolute;
  right: 34px;
  bottom: 28px;
  color: rgba(18, 24, 34, 0.34);
  font-family: var(--serif);
  font-weight: 800;
}

.slide-head {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  gap: 32px;
  align-items: start;
  margin-bottom: 32px;
}

.slide-kicker {
  margin: 0 0 12px;
  color: var(--gold);
  font-size: 11px;
  font-weight: 850;
  letter-spacing: 0.14em;
  text-transform: uppercase;
}

.slide h2 {
  max-width: 780px;
  margin: 0;
  font-family: var(--serif);
  font-size: 34px;
  line-height: 1.16;
  letter-spacing: 0;
}

.slide-summary {
  max-width: 330px;
  margin: 3px 0 0;
  color: var(--muted);
  font-size: 14px;
  line-height: 1.65;
}

.slide-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.05fr) minmax(380px, 0.95fr);
  gap: 30px;
  align-items: start;
}

.point-list {
  display: grid;
  gap: 13px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.point-list li {
  display: grid;
  grid-template-columns: 34px minmax(0, 1fr);
  gap: 12px;
  align-items: start;
  min-height: 64px;
  padding-bottom: 13px;
  border-bottom: 1px solid rgba(18, 24, 34, 0.1);
}

.source-body {
  max-height: 300px;
  overflow: auto;
  margin-top: 18px;
  padding: 16px;
  background: rgba(255, 250, 241, 0.74);
  border: 1px solid rgba(217, 209, 194, 0.9);
  color: #283241;
  font-size: 12.5px;
  line-height: 1.65;
}

.source-body h3,
.source-body h4 {
  margin: 12px 0 7px;
  color: var(--blue-deep);
  font-size: 14px;
}

.source-body p {
  margin: 0 0 8px;
}

.source-body ul,
.source-body ol {
  margin: 6px 0 10px 18px;
  padding: 0;
}

.source-body li {
  margin: 4px 0;
}

.source-body blockquote {
  margin: 10px 0;
  padding: 10px 12px;
  border-left: 3px solid var(--gold);
  background: #f7efe1;
}

.source-body table,
.resource-body table {
  width: 100%;
  margin: 12px 0;
  border-collapse: collapse;
  font-size: 12px;
}

.source-body th,
.source-body td,
.resource-body th,
.resource-body td {
  padding: 7px 8px;
  border: 1px solid var(--line);
  vertical-align: top;
}

.source-body th,
.resource-body th {
  background: #eef2fb;
  color: var(--blue-deep);
}

.source-body code,
.resource-body code {
  padding: 1px 5px;
  background: #eef2fb;
  color: var(--blue-deep);
}

.source-body pre,
.resource-body pre {
  overflow: auto;
  padding: 12px;
  background: #111925;
  color: #fffaf1;
}

.slide-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 14px;
}

.slide-action {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 34px;
  padding: 0 12px;
  border: 1px solid var(--blue);
  background: #eef2fb;
  color: var(--blue-deep);
  font-size: 12px;
  font-weight: 800;
  text-decoration: none;
}

.slide-action.quiz {
  border-color: var(--gold);
  background: #f7efe1;
  color: #7a4a10;
}

.point-list i {
  display: grid;
  place-items: center;
  width: 30px;
  height: 30px;
  background: var(--blue-deep);
  color: #fff;
  font-family: var(--serif);
  font-style: normal;
  font-weight: 800;
}

.point-list strong {
  display: block;
  margin-bottom: 4px;
  font-size: 16px;
}

.point-list span {
  display: block;
  color: var(--muted);
  font-size: 13px;
  line-height: 1.55;
}

.diagram-shell {
  min-height: 410px;
  padding: 12px;
  background: #f8f3e8;
  border: 1px solid var(--line);
}

.diagram-shell svg,
.graphic-art svg,
.dialog-art svg {
  display: block;
  width: 100%;
  height: auto;
}

.coach-panel {
  position: sticky;
  top: 24px;
  display: grid;
  gap: 14px;
}

.coach-panel > div {
  padding: 18px;
  background: #111925;
  color: #f9f3e8;
  border: 1px solid rgba(255, 255, 255, 0.1);
  box-shadow: 0 12px 32px rgba(18, 24, 34, 0.12);
}

.coach-panel h2 {
  margin: 0 0 10px;
  font-family: var(--serif);
  font-size: 22px;
  line-height: 1.2;
}

.coach-panel p:not(.panel-kicker) {
  margin: 0;
  color: rgba(249, 243, 232, 0.74);
  font-size: 13px;
  line-height: 1.72;
}

.deliverable-box strong {
  display: block;
  color: #fffaf1;
  font-size: 16px;
  line-height: 1.45;
}

.graphic-library {
  margin-top: 32px;
  padding: 28px;
  background: rgba(255, 250, 241, 0.86);
  border: 1px solid var(--line);
}

.section-head {
  display: flex;
  align-items: end;
  justify-content: space-between;
  gap: 18px;
  margin-bottom: 18px;
}

.section-head h2 {
  margin: 0;
  font-family: var(--serif);
  font-size: 30px;
}

.filter-row {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 18px;
}

.filter-btn {
  min-height: 34px;
  padding: 0 12px;
  border: 1px solid var(--line);
  background: #fffaf1;
  color: var(--muted);
  font-size: 12px;
  font-weight: 750;
}

.filter-btn.is-active {
  border-color: var(--blue);
  background: var(--blue);
  color: #fff;
}

.graphic-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 14px;
}

.graphic-card {
  display: grid;
  grid-template-rows: 160px auto;
  overflow: hidden;
  border: 1px solid var(--line);
  background: #fffaf1;
}

.graphic-card button {
  all: unset;
  cursor: pointer;
}

.graphic-art {
  display: grid;
  place-items: center;
  overflow: hidden;
  background: #f8f3e8;
  border-bottom: 1px solid var(--line);
}

.graphic-art svg {
  width: 100%;
}

.graphic-info {
  padding: 12px;
}

.graphic-info p {
  margin: 0 0 6px;
  color: var(--gold);
  font-size: 10px;
  font-weight: 800;
  letter-spacing: 0.1em;
  text-transform: uppercase;
}

.graphic-info h3 {
  margin: 0 0 8px;
  font-size: 15px;
  line-height: 1.35;
}

.graphic-info span {
  display: block;
  color: var(--muted);
  font-size: 12px;
  line-height: 1.48;
}

.preview-dialog {
  width: min(1080px, calc(100vw - 40px));
  padding: 0;
  border: 1px solid var(--line);
  background: var(--surface);
  color: var(--ink);
  box-shadow: 0 26px 80px rgba(18, 24, 34, 0.35);
}

.resource-dialog {
  width: min(980px, calc(100vw - 36px));
  max-height: min(860px, calc(100vh - 36px));
  padding: 0;
  border: 1px solid var(--line);
  background: var(--surface);
  color: var(--ink);
  box-shadow: 0 26px 80px rgba(18, 24, 34, 0.35);
}

.preview-dialog::backdrop,
.resource-dialog::backdrop {
  background: rgba(17, 25, 37, 0.62);
}

.dialog-head {
  display: flex;
  align-items: start;
  justify-content: space-between;
  gap: 18px;
  padding: 20px 22px 16px;
  border-bottom: 1px solid var(--line);
}

.dialog-head h2 {
  margin: 0;
  font-family: var(--serif);
  font-size: 28px;
}

.dialog-art {
  padding: 20px;
  background: #f8f3e8;
}

.dialog-actions {
  justify-content: flex-end;
  padding: 14px 20px 18px;
  border-top: 1px solid var(--line);
}

.resource-body {
  max-height: calc(100vh - 150px);
  overflow: auto;
  padding: 22px;
  color: #263142;
  font-size: 14px;
  line-height: 1.75;
}

.resource-body h3 {
  margin: 18px 0 9px;
  color: var(--blue-deep);
  font-size: 18px;
}

.resource-body h4 {
  margin: 14px 0 8px;
  color: var(--ink);
  font-size: 15px;
}

.resource-body p {
  margin: 0 0 10px;
}

.resource-body ul,
.resource-body ol {
  margin: 8px 0 14px 22px;
  padding: 0;
}

.resource-body blockquote {
  margin: 12px 0;
  padding: 12px 14px;
  border-left: 3px solid var(--gold);
  background: #f7efe1;
}

.quiz-list {
  display: grid;
  gap: 12px;
}

.quiz-card {
  padding: 14px;
  border: 1px solid var(--line);
  background: #fffaf1;
}

.quiz-card strong {
  display: block;
  margin-bottom: 10px;
}

.quiz-answer {
  display: none;
  margin-top: 10px;
  padding: 10px 12px;
  background: #eef5f3;
  color: #15594f;
  border-left: 3px solid var(--teal);
}

.quiz-card.is-revealed .quiz-answer {
  display: block;
}

.metric-strip {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 0;
  margin-top: 34px;
  border-top: 1px solid rgba(18, 24, 34, 0.16);
}

.metric-strip div {
  min-height: 86px;
  padding: 18px 18px 0 0;
}

.metric-strip strong {
  display: block;
  color: var(--blue-deep);
  font-family: var(--serif);
  font-size: 30px;
  line-height: 1;
}

.metric-strip span {
  display: block;
  margin-top: 8px;
  color: var(--muted);
  font-size: 12px;
}

.cover-slide .slide-inner {
  display: grid;
  grid-template-rows: auto 1fr auto;
}

.cover-mark {
  display: inline-grid;
  place-items: center;
  width: 74px;
  height: 74px;
  margin-bottom: 34px;
  background: #111925;
  color: #f5c46b;
  font-weight: 850;
}

.cover-title {
  max-width: 840px;
  font-family: var(--serif);
  font-size: 60px;
  line-height: 1.08;
}

.cover-subtitle {
  max-width: 620px;
  margin-top: 22px;
  color: var(--muted);
  font-size: 18px;
  line-height: 1.65;
}

.cover-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  padding-top: 24px;
  border-top: 1px solid rgba(18, 24, 34, 0.14);
  color: var(--muted);
  font-size: 13px;
}

@media (max-width: 1180px) {
  .course-app {
    grid-template-columns: 1fr;
  }

  .sidebar {
    position: relative;
    height: auto;
  }

  .module-nav {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .stage {
    grid-template-columns: 1fr;
  }

  .coach-panel {
    position: static;
    grid-template-columns: 1fr 1fr;
  }
}

@media (max-width: 860px) {
  .workspace {
    padding: 14px;
  }

  .slide {
    min-height: 0;
  }

  .slide-inner {
    min-height: 0;
    padding: 28px 22px 42px;
  }

  .slide-head,
  .slide-grid,
  .coach-panel,
  .metric-strip {
    grid-template-columns: 1fr;
  }

  .slide h2,
  .cover-title {
    font-size: 34px;
  }

  .graphic-grid {
    grid-template-columns: 1fr;
  }

  .module-nav {
    grid-template-columns: 1fr;
  }

  .topbar {
    align-items: flex-start;
    flex-direction: column;
  }

  .progress-wrap,
  .progress-track {
    width: 100%;
  }
}

@media print {
  body {
    background: #fff;
  }

  .sidebar,
  .topbar,
  .coach-panel,
  .graphic-library {
    display: none;
  }

  .course-app,
  .stage {
    display: block;
  }

  .workspace {
    padding: 0;
  }

  .slide {
    min-height: 0;
    border: none;
    box-shadow: none;
  }
}