:root {
  --bg: #f6f7f2;
  --surface: #ffffff;
  --surface-2: #eef4f1;
  --ink: #1d2527;
  --muted: #667174;
  --line: #d9dfdc;
  --teal: #14766f;
  --teal-2: #d9f0eb;
  --coral: #d9613c;
  --amber: #e4a11b;
  --indigo: #4357ad;
  --green: #3f8b4f;
  --shadow: 0 18px 50px rgba(28, 37, 39, 0.1);
  --radius: 8px;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-width: 320px;
  color: var(--ink);
  background:
    linear-gradient(180deg, rgba(217, 240, 235, 0.55), transparent 280px),
    var(--bg);
  font-family:
    Inter,
    "PingFang SC",
    "Microsoft YaHei",
    Arial,
    sans-serif;
  letter-spacing: 0;
}

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

button,
input,
textarea,
select {
  font: inherit;
}

img {
  display: block;
  max-width: 100%;
}

.topbar {
  position: sticky;
  top: 0;
  z-index: 20;
  display: grid;
  grid-template-columns: auto 1fr auto;
  gap: 24px;
  align-items: center;
  padding: 14px clamp(16px, 4vw, 48px);
  background: rgba(246, 247, 242, 0.92);
  border-bottom: 1px solid var(--line);
  backdrop-filter: blur(18px);
}

.brand {
  display: inline-flex;
  gap: 12px;
  align-items: center;
}

.brand-mark {
  display: grid;
  width: 42px;
  height: 42px;
  place-items: center;
  color: #fff;
  background: var(--teal);
  border-radius: var(--radius);
  font-weight: 800;
}

.brand strong,
.brand small {
  display: block;
  line-height: 1.15;
}

.brand small {
  margin-top: 3px;
  color: var(--muted);
  font-size: 12px;
}

.topnav {
  display: flex;
  justify-content: center;
  gap: 6px;
}

.topnav a {
  padding: 10px 14px;
  color: var(--muted);
  border-radius: var(--radius);
  font-size: 14px;
  font-weight: 700;
}

.topnav a.active,
.topnav a:hover {
  color: var(--teal);
  background: var(--teal-2);
}

main {
  width: min(1440px, 100%);
  margin: 0 auto;
  padding: 28px clamp(16px, 4vw, 48px) 56px;
}

.hidden {
  display: none !important;
}

.primary-button,
.secondary-button,
.ghost-button,
.danger-button,
.small-button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  min-height: 42px;
  border: 1px solid transparent;
  border-radius: var(--radius);
  cursor: pointer;
  font-weight: 800;
  transition:
    transform 0.18s ease,
    box-shadow 0.18s ease,
    background 0.18s ease;
}

.primary-button {
  padding: 0 18px;
  color: #fff;
  background: var(--teal);
  box-shadow: 0 10px 24px rgba(20, 118, 111, 0.22);
}

.secondary-button,
.ghost-button,
.small-button {
  color: var(--ink);
  background: var(--surface);
  border-color: var(--line);
}

.danger-button {
  padding: 0 18px;
  color: #fff;
  background: var(--coral);
}

.ghost-button {
  padding: 0 14px;
}

.small-button {
  min-height: 34px;
  padding: 0 10px;
  font-size: 13px;
}

.primary-button:hover,
.secondary-button:hover,
.ghost-button:hover,
.danger-button:hover,
.small-button:hover {
  transform: translateY(-1px);
  box-shadow: 0 10px 26px rgba(28, 37, 39, 0.12);
}

.primary-button:disabled,
.secondary-button:disabled,
.ghost-button:disabled,
.small-button:disabled {
  cursor: not-allowed;
  opacity: 0.52;
  transform: none;
  box-shadow: none;
}

svg {
  width: 18px;
  height: 18px;
  stroke-width: 2.2;
}

.dashboard-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 320px;
  gap: 18px;
  align-items: stretch;
}

.hero-panel {
  display: grid;
  grid-template-columns: minmax(0, 1.15fr) minmax(260px, 0.85fr);
  gap: 28px;
  min-height: 420px;
  padding: clamp(22px, 4vw, 42px);
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

.hero-copy {
  align-self: center;
}

.eyebrow,
.panel-label {
  display: inline-flex;
  margin: 0 0 10px;
  color: var(--coral);
  font-size: 12px;
  font-weight: 900;
  letter-spacing: 0;
  text-transform: uppercase;
}

.hero-copy h1,
.section-head h1,
.section-head h2,
.lesson-header h1,
.report-paper h1 {
  margin: 0;
  line-height: 1.08;
  letter-spacing: 0;
}

.hero-copy h1 {
  max-width: 760px;
  font-size: clamp(34px, 5vw, 68px);
}

.hero-copy p:not(.eyebrow) {
  max-width: 680px;
  color: var(--muted);
  font-size: 18px;
  line-height: 1.7;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 28px;
}

.hero-visual {
  display: grid;
  align-content: end;
  gap: 12px;
  margin: 0;
}

.hero-visual img {
  width: 100%;
  max-height: 340px;
  object-fit: cover;
  border-radius: var(--radius);
  border: 1px solid var(--line);
}

.hero-visual figcaption {
  color: var(--muted);
  font-size: 13px;
}

.status-panel,
.module-band,
.module-card,
.task-card,
.resource-rail section,
.works-card,
.report-paper {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
}

.status-panel {
  display: grid;
  align-content: start;
  gap: 22px;
  padding: 24px;
  box-shadow: var(--shadow);
}

.status-panel strong {
  display: block;
  font-size: 52px;
  line-height: 1;
}

.progress-track {
  height: 10px;
  overflow: hidden;
  background: #e7ece8;
  border-radius: 999px;
}

.progress-track span {
  display: block;
  width: 0;
  height: 100%;
  background: linear-gradient(90deg, var(--teal), var(--green), var(--amber));
  border-radius: inherit;
  transition: width 0.28s ease;
}

.progress-track.compact {
  width: 140px;
  height: 8px;
}

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

.stat-list div {
  padding: 14px 10px;
  background: var(--surface-2);
  border-radius: var(--radius);
}

.stat-list dt {
  color: var(--muted);
  font-size: 12px;
}

.stat-list dd {
  margin: 6px 0 0;
  font-size: 26px;
  font-weight: 900;
}

.module-band {
  margin-top: 18px;
  padding: 24px;
}

.section-head {
  display: flex;
  justify-content: space-between;
  gap: 20px;
  align-items: end;
  margin-bottom: 20px;
}

.section-head h1 {
  font-size: clamp(32px, 4vw, 56px);
}

.section-head h2 {
  font-size: clamp(24px, 3vw, 36px);
}

.module-grid {
  display: grid;
  grid-template-columns: repeat(7, minmax(150px, 1fr));
  gap: 12px;
}

.module-card {
  display: grid;
  gap: 14px;
  min-height: 210px;
  padding: 16px;
}

.module-card.locked {
  opacity: 0.62;
}

.module-card h3 {
  margin: 0;
  font-size: 18px;
  line-height: 1.25;
}

.module-card p {
  margin: 0;
  color: var(--muted);
  font-size: 13px;
  line-height: 1.55;
}

.module-number {
  display: inline-grid;
  width: 32px;
  height: 32px;
  place-items: center;
  color: #fff;
  background: var(--indigo);
  border-radius: var(--radius);
  font-weight: 900;
}

.module-meta {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-top: auto;
  color: var(--muted);
  font-size: 12px;
}

.course-shell {
  display: grid;
  grid-template-columns: 300px minmax(0, 1fr);
  gap: 18px;
}

.module-sidebar {
  position: sticky;
  top: 86px;
  align-self: start;
  max-height: calc(100vh - 110px);
  overflow: auto;
  padding: 18px;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
}

.sidebar-head h2 {
  margin: 0 0 14px;
  font-size: 24px;
}

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

.module-nav-button {
  display: grid;
  grid-template-columns: 34px 1fr auto;
  gap: 10px;
  align-items: center;
  width: 100%;
  padding: 12px;
  color: var(--ink);
  text-align: left;
  background: #f8faf7;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  cursor: pointer;
}

.module-nav-button.active {
  border-color: var(--teal);
  background: var(--teal-2);
}

.module-nav-button:disabled {
  cursor: not-allowed;
  opacity: 0.58;
}

.module-nav-button strong,
.module-nav-button small {
  display: block;
}

.module-nav-button small {
  margin-top: 3px;
  color: var(--muted);
}

.lesson-stage {
  min-width: 0;
}

.lesson-header {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 20px;
  align-items: start;
  margin-bottom: 18px;
  padding: 24px;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
}

.lesson-header h1 {
  font-size: clamp(30px, 4vw, 52px);
}

.lesson-header p {
  max-width: 840px;
  margin: 12px 0 0;
  color: var(--muted);
  font-size: 16px;
  line-height: 1.7;
}

.module-score {
  display: grid;
  gap: 8px;
  justify-items: end;
  font-weight: 900;
}

.lesson-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 320px;
  gap: 18px;
}

.task-surface {
  min-width: 0;
}

.task-tabs {
  display: flex;
  gap: 8px;
  margin-bottom: 12px;
  overflow-x: auto;
  padding-bottom: 2px;
}

.task-tab {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  white-space: nowrap;
  min-height: 38px;
  padding: 0 12px;
  color: var(--muted);
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  cursor: pointer;
  font-weight: 800;
}

.task-tab.active {
  color: var(--teal);
  background: var(--teal-2);
  border-color: var(--teal);
}

.task-tab.complete {
  color: var(--green);
}

.task-card {
  padding: 24px;
}

.chapter-content {
  margin-top: 18px;
  padding: 24px;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
}

.license-note {
  margin: -8px 0 18px;
  color: var(--muted);
  font-size: 13px;
  line-height: 1.7;
}

.chapter-overview {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
  margin-bottom: 18px;
}

.chapter-summary-card {
  padding: 16px;
  background: #f8faf7;
  border: 1px solid var(--line);
  border-radius: var(--radius);
}

.chapter-summary-card h3,
.mini-block h4 {
  margin: 0 0 10px;
  font-size: 16px;
}

.chapter-summary-card ul,
.mini-block ul {
  display: grid;
  gap: 8px;
  padding: 0;
  margin: 0;
  list-style: none;
}

.chapter-summary-card li,
.mini-block li {
  color: var(--muted);
  line-height: 1.65;
}

.section-reader {
  display: grid;
  gap: 10px;
}

.chapter-section {
  overflow: hidden;
  background: #fff;
  border: 1px solid var(--line);
  border-radius: var(--radius);
}

.chapter-section summary {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  align-items: center;
  padding: 15px 16px;
  cursor: pointer;
  font-weight: 900;
}

.chapter-section summary small {
  flex: 0 0 auto;
  color: var(--muted);
  font-size: 12px;
  font-weight: 800;
}

.article-flow {
  display: grid;
  gap: 14px;
  padding: 0 16px 18px;
}

.chapter-intro-flow {
  padding: 0;
  margin-bottom: 18px;
}

.article-paragraph {
  max-width: 74ch;
  margin: 0;
  color: var(--muted);
  font-size: 15px;
  line-height: 1.9;
}

.article-figure {
  width: min(100%, 820px);
  margin: 4px auto 10px;
  overflow: hidden;
  background: #fff;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: 0 14px 34px rgba(30, 45, 38, 0.08);
}

.article-figure img {
  display: block;
  width: 100%;
  max-height: 560px;
  object-fit: contain;
  background: #f3f6f2;
}

.article-figure figcaption {
  display: grid;
  gap: 4px;
  padding: 12px 14px 14px;
  color: var(--ink);
  font-size: 13px;
  line-height: 1.45;
}

.mini-block {
  padding: 14px;
  background: var(--surface-2);
  border-radius: var(--radius);
}

.task-card h2 {
  margin: 0;
  font-size: clamp(24px, 3vw, 36px);
}

.task-card > p {
  margin: 12px 0 18px;
  color: var(--muted);
  line-height: 1.75;
}

.objective-list,
.option-list,
.mini-checklist,
.feedback-list {
  padding: 0;
  margin: 0;
  list-style: none;
}

.objective-list {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 10px;
  margin: 18px 0;
}

.objective-list li,
.option-item,
.mini-checklist li,
.feedback-list li {
  padding: 12px;
  background: #f8faf7;
  border: 1px solid var(--line);
  border-radius: var(--radius);
}

.content-columns {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px;
}

.info-box {
  padding: 16px;
  background: var(--surface-2);
  border-radius: var(--radius);
}

.info-box h3 {
  margin: 0 0 10px;
}

.info-box p {
  margin: 0;
  color: var(--muted);
  line-height: 1.65;
}

.field-grid {
  display: grid;
  gap: 12px;
}

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

label {
  display: grid;
  gap: 7px;
  color: var(--muted);
  font-size: 13px;
  font-weight: 800;
}

input[type="text"],
input[type="url"],
textarea,
select {
  width: 100%;
  min-height: 44px;
  padding: 11px 12px;
  color: var(--ink);
  background: #fff;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  outline: none;
}

textarea {
  min-height: 130px;
  resize: vertical;
  line-height: 1.65;
}

input:focus,
textarea:focus,
select:focus {
  border-color: var(--teal);
  box-shadow: 0 0 0 3px rgba(20, 118, 111, 0.12);
}

.prompt-preview {
  margin: 16px 0;
  padding: 16px;
  background: #202928;
  color: #eff8f4;
  border-radius: var(--radius);
  line-height: 1.75;
}

.prompt-preview mark {
  color: #fff;
  background: rgba(228, 161, 27, 0.55);
  border-radius: 5px;
}

.reference-answer {
  margin: 14px 0 0;
  padding: 16px;
  background: #fff7e3;
  border: 1px solid rgba(228, 161, 27, 0.45);
  border-radius: var(--radius);
  line-height: 1.7;
}

.button-row {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 16px;
}

.sort-list {
  display: grid;
  gap: 8px;
  margin: 16px 0;
  padding: 0;
  list-style: none;
}

.sort-item {
  display: grid;
  grid-template-columns: auto 1fr auto;
  gap: 10px;
  align-items: center;
  padding: 12px;
  background: #f8faf7;
  border: 1px solid var(--line);
  border-radius: var(--radius);
}

.sort-item.dragging {
  opacity: 0.45;
}

.drag-handle {
  color: var(--muted);
}

.sort-actions {
  display: inline-flex;
  align-items: center;
  gap: 6px;
}

.sort-actions strong {
  min-width: 20px;
  text-align: right;
}

.icon-only {
  width: 34px;
  padding: 0;
}

.option-list {
  display: grid;
  gap: 10px;
  margin: 16px 0;
}

.option-item {
  display: flex;
  gap: 10px;
  align-items: flex-start;
  cursor: pointer;
}

.option-item input {
  margin-top: 3px;
}

.check-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 10px;
  margin: 16px 0;
}

.check-tile {
  display: flex;
  gap: 10px;
  align-items: flex-start;
  padding: 12px;
  color: var(--ink);
  background: #f8faf7;
  border: 1px solid var(--line);
  border-radius: var(--radius);
}

.submission-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 14px;
}

.file-label {
  min-height: 94px;
  padding: 14px;
  background: #f8faf7;
  border: 1px dashed var(--teal);
  border-radius: var(--radius);
}

.file-label input {
  color: var(--muted);
}

.resource-rail {
  display: grid;
  gap: 14px;
  align-content: start;
}

.resource-rail section {
  padding: 16px;
}

.asset-strip {
  display: grid;
  gap: 10px;
}

.asset-card {
  display: grid;
  grid-template-columns: 78px 1fr;
  gap: 10px;
  align-items: center;
}

.asset-card img {
  width: 78px;
  height: 58px;
  object-fit: cover;
  border: 1px solid var(--line);
  border-radius: var(--radius);
}

.asset-card strong,
.asset-card small {
  display: block;
}

.asset-card small {
  margin-top: 4px;
  color: var(--muted);
}

.template-box {
  padding: 12px;
  background: #202928;
  color: #eff8f4;
  border-radius: var(--radius);
  font-size: 13px;
  line-height: 1.65;
}

.mini-checklist {
  display: grid;
  gap: 8px;
}

.mini-checklist li {
  color: var(--muted);
  font-size: 13px;
}

.toast {
  margin-top: 14px;
  padding: 12px;
  color: #113c34;
  background: var(--teal-2);
  border: 1px solid rgba(20, 118, 111, 0.24);
  border-radius: var(--radius);
  font-weight: 800;
}

.toast.warn {
  color: #6b3f03;
  background: #fff2cf;
  border-color: rgba(228, 161, 27, 0.45);
}

.works-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 16px;
}

.works-card {
  padding: 18px;
}

.works-card h2 {
  margin: 0 0 10px;
}

.works-card dl {
  display: grid;
  gap: 10px;
  margin: 0;
}

.works-card dt {
  color: var(--muted);
  font-size: 12px;
  font-weight: 900;
}

.works-card dd {
  margin: 4px 0 0;
  overflow-wrap: anywhere;
  line-height: 1.55;
}

.empty-state {
  padding: 28px;
  color: var(--muted);
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
}

.report-paper {
  padding: clamp(22px, 4vw, 42px);
  box-shadow: var(--shadow);
}

.report-summary {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 12px;
  margin: 18px 0;
}

.report-metric {
  padding: 16px;
  background: var(--surface-2);
  border-radius: var(--radius);
}

.report-metric span {
  display: block;
  color: var(--muted);
  font-size: 12px;
  font-weight: 900;
}

.report-metric strong {
  display: block;
  margin-top: 8px;
  font-size: 32px;
}

.report-block {
  margin-top: 24px;
  padding-top: 20px;
  border-top: 1px solid var(--line);
}

.report-block h2 {
  margin: 0 0 12px;
}

.report-block ul {
  display: grid;
  gap: 8px;
  padding: 0;
  margin: 0;
  list-style: none;
}

.report-block li {
  padding: 12px;
  background: #f8faf7;
  border: 1px solid var(--line);
  border-radius: var(--radius);
}

.badge {
  display: inline-flex;
  align-items: center;
  min-height: 26px;
  padding: 0 9px;
  color: var(--teal);
  background: var(--teal-2);
  border-radius: 999px;
  font-size: 12px;
  font-weight: 900;
}

.badge.warn {
  color: #7a4d00;
  background: #fff0c7;
}

@media (max-width: 1180px) {
  .dashboard-grid,
  .hero-panel,
  .course-shell,
  .lesson-layout {
    grid-template-columns: 1fr;
  }

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

  .module-sidebar {
    position: static;
    max-height: none;
  }

  .resource-rail {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

@media (max-width: 760px) {
  .topbar {
    grid-template-columns: 1fr auto;
  }

  .topnav {
    grid-column: 1 / -1;
    justify-content: flex-start;
    overflow-x: auto;
  }

  .ghost-button span {
    display: none;
  }

  .module-grid,
  .works-grid,
  .resource-rail,
  .chapter-overview,
    .objective-list,
  .content-columns,
  .field-grid.two,
  .check-grid,
  .submission-grid,
  .report-summary {
    grid-template-columns: 1fr;
  }

  .article-flow {
    padding-inline: 12px;
  }

  .article-figure img {
    max-height: 420px;
  }

  .lesson-header {
    grid-template-columns: 1fr;
  }

  .module-score {
    justify-items: start;
  }

  .hero-copy h1 {
    font-size: 36px;
  }
}