:root {
  color-scheme: light;
  --ink: #20242c;
  --muted: #666666;
  --soft: #8a8a8a;
  --line: #dedede;
  --paper: #f4f4f2;
  --panel: #ffffff;
  --panel-soft: #eeeeec;
  --black: #20242c;
  --accent: #2aa866;
}

body.atlas-learn {
  --atlas-bg: #f5f6f8;
  --atlas-panel: #ffffff;
  --atlas-sidebar: #f0f2f5;
  --atlas-active: #e9edf2;
  --atlas-line: #c9d0da;
  --atlas-ink: #20242c;
  --atlas-muted: #596473;
  --atlas-dim: #7a8493;
  --atlas-green: #2aa866;
  display: flex;
  height: 100vh;
  overflow: hidden;
  color: var(--atlas-ink);
  background: var(--atlas-bg);
  user-select: none;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  color: var(--ink);
  background: var(--paper);
  font-size: 14px;
  letter-spacing: 0;
}

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

.topbar {
  position: sticky;
  top: 0;
  z-index: 20;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  min-height: 60px;
  padding: 0 44px;
  background: rgba(244, 244, 242, 0.9);
  border-bottom: 1px solid var(--line);
  backdrop-filter: blur(18px);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-size: 14px;
  font-weight: 700;
}

.brand-mark {
  display: inline-grid;
  place-items: center;
  width: 34px;
  height: 34px;
  border-radius: 6px;
  color: #fff;
  background: var(--black);
  font-size: 12px;
  letter-spacing: 0;
}

.nav {
  display: flex;
  gap: 20px;
  color: var(--muted);
  font-size: 13px;
}

.nav a:hover {
  color: var(--accent);
}

.nav-cta,
.button,
.signup button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 38px;
  padding: 0 15px;
  border-radius: 6px;
  font-size: 13px;
  font-weight: 650;
}

.nav-cta,
.button.primary,
.signup button {
  color: #fff;
  background: var(--black);
  border: 1px solid var(--black);
}

.button.secondary {
  color: var(--black);
  border: 1px solid var(--line);
  background: rgba(255, 255, 255, 0.68);
}

.hero {
  display: grid;
  grid-template-columns: minmax(0, 0.86fr) minmax(420px, 1.14fr);
  gap: 42px;
  align-items: center;
  min-height: calc(100vh - 60px);
  padding: 58px 44px 38px;
}

.hero-copy {
  max-width: 620px;
}

.eyebrow {
  margin: 0 0 12px;
  color: var(--soft);
  font-size: 11px;
  font-weight: 750;
  text-transform: uppercase;
}

h1,
h2,
h3,
p {
  margin-top: 0;
}

h1 {
  max-width: 620px;
  margin-bottom: 18px;
  font-size: clamp(38px, 5.2vw, 72px);
  line-height: 1;
  font-weight: 760;
  letter-spacing: 0;
}

h2 {
  margin-bottom: 14px;
  font-size: 31px;
  line-height: 1.18;
  font-weight: 720;
  letter-spacing: 0;
}

h3 {
  margin-bottom: 10px;
  font-size: 17px;
  line-height: 1.3;
  font-weight: 700;
  letter-spacing: 0;
}

.lead {
  max-width: 560px;
  color: var(--muted);
  font-size: 16px;
  line-height: 1.72;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin: 26px 0 30px;
}

.metrics {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 8px;
  max-width: 510px;
  margin: 0;
}

.metrics div {
  padding: 14px;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: rgba(255, 255, 255, 0.62);
}

.metrics dt {
  color: var(--accent);
  font-size: 24px;
  font-weight: 760;
}

.metrics dd {
  margin: 3px 0 0;
  color: var(--muted);
  font-size: 12px;
}

.hero-media {
  margin: 0;
}

.hero-media img {
  display: block;
  width: 100%;
  aspect-ratio: 16 / 10;
  object-fit: cover;
  border: 1px solid var(--line);
  border-radius: 6px;
  filter: grayscale(0.82) contrast(0.92) brightness(1.08);
}

.section {
  padding: 64px 44px;
  border-top: 1px solid var(--line);
}

.section-head {
  max-width: 720px;
  margin-bottom: 26px;
}

.section-text {
  max-width: 600px;
  color: var(--muted);
  font-size: 15px;
  line-height: 1.75;
}

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

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

.card,
.agent-card,
.signup,
.timeline > div {
  border: 1px solid var(--line);
  border-radius: 6px;
  background: rgba(255, 255, 255, 0.72);
}

.card,
.agent-card {
  padding: 22px;
}

.card p,
.agent-card p,
.timeline p {
  color: var(--muted);
  font-size: 14px;
  line-height: 1.7;
}

.split {
  display: grid;
  grid-template-columns: minmax(0, 0.86fr) minmax(360px, 1.14fr);
  gap: 34px;
  align-items: start;
}

.timeline {
  display: grid;
  gap: 10px;
}

.timeline > div {
  padding: 18px;
}

.timeline span,
.agent-badge {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 42px;
  height: 24px;
  margin-bottom: 9px;
  border-radius: 999px;
  color: var(--ink);
  background: var(--panel-soft);
  border: 1px solid var(--line);
  font-size: 11px;
  font-weight: 760;
}

.timeline strong {
  display: block;
  margin-bottom: 6px;
  font-size: 16px;
  line-height: 1.35;
}

.agent-card a {
  display: inline-flex;
  margin-top: 8px;
  color: var(--accent);
  font-size: 13px;
  font-weight: 750;
  border-bottom: 1px solid var(--accent);
}

.signup {
  display: grid;
  gap: 14px;
  padding: 22px;
}

.signup label {
  display: grid;
  gap: 7px;
  color: var(--muted);
  font-size: 13px;
  font-weight: 650;
}

.signup input,
.signup select,
.signup textarea {
  width: 100%;
  border: 1px solid var(--line);
  border-radius: 6px;
  padding: 11px 12px;
  color: var(--ink);
  background: #fff;
  font: inherit;
}

.signup textarea {
  resize: vertical;
}

.form-note {
  margin: 0;
  color: var(--soft);
  font-size: 12px;
}

.learn-body {
  min-height: 100vh;
  overflow: hidden;
}

.learn-topbar {
  display: none;
}

.learn-status {
  display: flex;
  align-items: center;
  gap: 8px;
  color: var(--muted);
  font-size: 12px;
}

.learn-status a,
.learn-status span {
  padding: 6px 9px;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.7);
}

.learn-shell {
  display: grid;
  grid-template-columns: 52px 292px minmax(0, 1fr) 352px;
  height: 100vh;
}

.app-rail {
  display: grid;
  align-content: start;
  gap: 4px;
  padding: 8px 5px;
  border-right: 1px solid #2c2c2c;
  background: #151515;
}

.app-rail a {
  display: grid;
  justify-items: center;
  gap: 4px;
  padding: 7px 2px;
  border: 1px solid transparent;
  border-radius: 7px;
  color: #a8a8a8;
  font-size: 10px;
}

.app-rail a.active,
.app-rail a:hover {
  color: #fff;
  border-color: #333;
  background: #262626;
}

.app-rail a.active::before {
  content: "";
  position: absolute;
  left: 0;
  width: 2px;
  height: 28px;
  border-radius: 999px;
  background: #fff;
}

.app-rail span {
  display: grid;
  place-items: center;
  width: 30px;
  height: 30px;
  border-radius: 7px;
  color: #151515;
  background: #f5f5f2;
  font-size: 12px;
  font-weight: 800;
}

.app-rail strong {
  font-size: 10px;
}

.learn-sidebar,
.qa-panel {
  min-height: 0;
  overflow: auto;
  padding: 18px;
  border-right: 1px solid var(--line);
  background: #f0f0ee;
}

.profile-strip,
.brain-card {
  margin-bottom: 16px;
  padding: 14px;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: rgba(255, 255, 255, 0.72);
}

.profile-strip span {
  display: block;
  margin-bottom: 6px;
  color: var(--soft);
  font-size: 11px;
  font-weight: 750;
}

.profile-strip strong {
  display: block;
  margin-bottom: 5px;
  font-size: 14px;
}

.profile-strip p,
.brain-card p,
.brain-card li {
  color: var(--muted);
  font-size: 12px;
  line-height: 1.65;
}

.profile-strip p,
.brain-card p {
  margin: 0;
}

.brain-card ul {
  display: grid;
  gap: 5px;
  padding-left: 17px;
  margin: 10px 0 0;
}

.qa-panel {
  border-right: 0;
  border-left: 1px solid var(--line);
}

.panel-title {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  margin-bottom: 14px;
  color: var(--muted);
  font-size: 12px;
}

.panel-title strong {
  color: var(--ink);
  font-size: 12px;
}

.course-switch {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 6px;
  margin-bottom: 16px;
}

.course-switch button,
.slide-toolbar button,
.audio-bar button,
.assignment-bar button,
.qa-input button {
  min-height: 34px;
  border: 1px solid var(--line);
  border-radius: 6px;
  color: var(--ink);
  background: #fff;
  font: inherit;
  font-size: 12px;
  font-weight: 700;
}

.course-switch button.active,
.slide-toolbar button,
.assignment-bar button,
.qa-input button {
  color: #fff;
  background: var(--black);
  border-color: var(--black);
}

.lesson-list {
  display: grid;
  gap: 8px;
  padding: 0;
  margin: 0 0 18px;
  list-style: none;
}

.lesson-list li {
  display: grid;
  grid-template-columns: 34px 1fr;
  gap: 10px;
  padding: 12px;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: rgba(255, 255, 255, 0.68);
}

.lesson-list li.active {
  border-color: var(--ink);
  background: #fff;
}

.lesson-list span {
  display: grid;
  place-items: center;
  width: 30px;
  height: 30px;
  border-radius: 999px;
  background: var(--paper);
  font-size: 11px;
  font-weight: 800;
}

.lesson-list strong {
  display: block;
  margin-bottom: 3px;
  font-size: 13px;
}

.lesson-list small,
.sidebar-note p,
.chat p,
.assignment-bar p {
  color: var(--muted);
  font-size: 12px;
  line-height: 1.65;
}

.sidebar-note {
  padding: 14px;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: rgba(255, 255, 255, 0.7);
}

.sidebar-note strong {
  font-size: 13px;
}

.sidebar-note p {
  margin: 6px 0 0;
}

.lesson-stage {
  display: grid;
  grid-template-rows: auto auto minmax(0, 1fr) auto auto;
  min-width: 0;
  min-height: 0;
  padding: 0 22px 22px;
  overflow: auto;
  background: #f7f7f5;
}

.lesson-tabs {
  display: flex;
  align-items: flex-end;
  gap: 2px;
  min-height: 34px;
  margin: 0 -22px 16px;
  padding: 0 10px;
  border-bottom: 1px solid var(--line);
  background: #fff;
}

.lesson-tabs button {
  min-height: 33px;
  padding: 0 13px;
  border: 1px solid transparent;
  border-bottom: 0;
  border-radius: 6px 6px 0 0;
  color: var(--muted);
  background: transparent;
  font: inherit;
  font-size: 12px;
  font-weight: 700;
}

.lesson-tabs button.active {
  color: var(--ink);
  border-color: var(--line);
  background: var(--paper);
}

.slide-toolbar {
  display: flex;
  align-items: start;
  justify-content: space-between;
  gap: 18px;
  margin-bottom: 16px;
}

.slide-toolbar h1 {
  margin-bottom: 0;
  font-size: 28px;
  line-height: 1.16;
}

.slide-card {
  display: grid;
  align-content: center;
  min-height: 430px;
  padding: 42px;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: #fff;
}

.slide-kicker {
  color: var(--soft);
  font-size: 12px;
  font-weight: 750;
}

.slide-card h2 {
  max-width: 760px;
  font-size: 34px;
}

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

.slide-grid div {
  padding: 14px;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: var(--paper);
}

.slide-grid span {
  display: block;
  margin-bottom: 6px;
  color: var(--soft);
  font-size: 11px;
}

.slide-grid strong {
  font-size: 13px;
}

.audio-bar {
  display: grid;
  grid-template-columns: auto 1fr auto;
  gap: 12px;
  align-items: center;
  padding: 12px 0;
}

.audio-track {
  height: 6px;
  border-radius: 999px;
  background: #d8d8d6;
  overflow: hidden;
}

.audio-track span {
  display: block;
  width: 44%;
  height: 100%;
  background: var(--black);
}

.audio-bar time {
  color: var(--muted);
  font-size: 12px;
}

.assignment-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
  padding: 16px;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: rgba(255, 255, 255, 0.74);
}

.assignment-bar h3 {
  margin-bottom: 4px;
  font-size: 16px;
}

.assignment-bar p {
  margin: 0;
}

.chat-list {
  display: grid;
  gap: 10px;
  margin-bottom: 14px;
}

.agent-tabs {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 6px;
  margin-bottom: 12px;
}

.agent-tabs button {
  min-height: 30px;
  border: 1px solid var(--line);
  border-radius: 6px;
  color: var(--muted);
  background: rgba(255, 255, 255, 0.72);
  font: inherit;
  font-size: 12px;
  font-weight: 700;
}

.agent-tabs button.active {
  color: #fff;
  background: var(--black);
  border-color: var(--black);
}

.chat {
  padding: 12px;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: rgba(255, 255, 255, 0.72);
}

.chat.user {
  background: #fff;
}

.chat strong {
  display: block;
  margin-bottom: 5px;
  font-size: 12px;
}

.chat p {
  margin: 0;
}

.qa-input {
  display: grid;
  gap: 8px;
}

.qa-input textarea {
  width: 100%;
  border: 1px solid var(--line);
  border-radius: 6px;
  padding: 11px;
  resize: vertical;
  font: inherit;
  font-size: 13px;
}

.settings-panel {
  margin-top: 18px;
  padding-top: 16px;
  border-top: 1px solid var(--line);
}

.settings-panel label {
  display: grid;
  gap: 7px;
  margin-bottom: 12px;
  color: var(--muted);
  font-size: 12px;
  font-weight: 650;
}

.settings-panel select {
  width: 100%;
  border: 1px solid var(--line);
  border-radius: 6px;
  padding: 9px 10px;
  color: var(--ink);
  background: #fff;
  font: inherit;
  font-size: 12px;
}

.settings-panel .toggle-row {
  display: flex;
  align-items: center;
  gap: 8px;
  color: var(--ink);
}

@media (max-width: 900px) {
  .topbar {
    padding: 0 18px;
  }

  .nav {
    display: none;
  }

  .hero,
  .split,
  .grid.three {
    grid-template-columns: 1fr;
  }

  .hero {
    min-height: auto;
    padding: 38px 18px 32px;
  }

  .section {
    padding: 48px 18px;
  }

  h1 {
    font-size: 42px;
  }

  h2 {
    font-size: 26px;
  }

  .hero-media {
    order: -1;
  }

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

  .learn-body {
    overflow: auto;
  }

  .learn-shell {
    grid-template-columns: 1fr;
    height: auto;
  }

  .app-rail {
    grid-auto-flow: column;
    grid-template-columns: repeat(5, 1fr);
    overflow: auto;
    border-right: 0;
    border-bottom: 1px solid var(--line);
  }

  .learn-sidebar,
  .qa-panel {
    border: 0;
    border-bottom: 1px solid var(--line);
  }

  .slide-card {
    min-height: 360px;
    padding: 24px;
  }

  .slide-card h2 {
    font-size: 25px;
  }

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

  .assignment-bar,
  .slide-toolbar {
    align-items: stretch;
    flex-direction: column;
  }
}

/* Atlas-style learning workspace */
.atlas-learn .activity-bar {
  width: 48px;
  flex-shrink: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 2px;
  padding: 8px 0;
  border-right: 1px solid var(--atlas-line);
  background: var(--atlas-sidebar);
}

.atlas-learn .ab-item {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  border-radius: 8px;
  color: var(--atlas-muted);
  font-size: 0;
}

.atlas-learn .ab-item svg {
  width: 20px;
  height: 20px;
}

.atlas-learn .ab-item:hover,
.atlas-learn .ab-item.active {
  color: var(--atlas-ink);
  background: var(--atlas-active);
}

.atlas-learn .ab-item.active::before {
  content: "";
  position: absolute;
  left: -4px;
  top: 9px;
  bottom: 9px;
  width: 2px;
  border-radius: 1px;
  background: var(--atlas-green);
}

.atlas-learn .ab-spacer {
  flex: 1;
}

.atlas-sidebar {
  width: 280px;
  flex-shrink: 0;
  display: flex;
  flex-direction: column;
  overflow: hidden;
  border-right: 1px solid var(--atlas-line);
  background: var(--atlas-panel);
}

.atlas-learn .sidebar-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: 40px;
  padding: 0 14px;
  color: var(--atlas-dim);
  font-size: 11px;
  font-weight: 700;
  text-transform: uppercase;
}

.atlas-learn .sidebar-header button {
  width: 24px;
  height: 24px;
  border: 0;
  border-radius: 6px;
  color: var(--atlas-muted);
  background: transparent;
  font-size: 16px;
}

.atlas-learn .sidebar-header button:hover {
  background: var(--atlas-active);
}

.atlas-learn .sidebar-body {
  flex: 1;
  overflow: auto;
  padding: 6px 0 12px;
}

.atlas-block {
  margin: 8px 10px;
  padding: 12px;
  border: 1px solid transparent;
  border-radius: 10px;
  background: var(--atlas-active);
}

.atlas-block .block-label {
  margin-bottom: 7px;
  color: var(--atlas-dim);
  font-size: 11px;
  font-weight: 800;
}

.atlas-block h2 {
  margin-bottom: 6px;
  font-size: 15px;
  line-height: 1.3;
}

.atlas-block p {
  margin: 0;
  color: var(--atlas-muted);
  font-size: 12px;
  line-height: 1.55;
}

.atlas-learn .course-tabs {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 6px;
  margin-bottom: 10px;
}

.atlas-learn .course-tabs button,
.atlas-learn .right-tabs button,
.atlas-learn .workspace-head button,
.atlas-learn .atlas-assignment button,
.atlas-learn .chat-input-bar button {
  border: 1px solid var(--atlas-line);
  border-radius: 7px;
  color: var(--atlas-ink);
  background: var(--atlas-panel);
  font: inherit;
  font-size: 12px;
  font-weight: 700;
}

.atlas-learn .course-tabs button.active,
.atlas-learn .right-tabs button.active,
.atlas-learn .workspace-head button,
.atlas-learn .atlas-assignment button,
.atlas-learn .chat-input-bar button {
  color: #fff;
  border-color: var(--black);
  background: var(--black);
}

.atlas-learn .tree-item {
  display: grid;
  grid-template-columns: 28px minmax(0, 1fr) auto;
  align-items: center;
  gap: 8px;
  margin: 4px -4px;
  padding: 8px;
  border-left: 2px solid transparent;
  border-radius: 7px;
  color: var(--atlas-muted);
  font-size: 12px;
}

.atlas-learn .tree-item:hover,
.atlas-learn .tree-item.active {
  color: var(--atlas-ink);
  background: var(--atlas-panel);
}

.atlas-learn .tree-item.active {
  border-left-color: var(--atlas-green);
}

.atlas-learn .tree-item span {
  display: grid;
  place-items: center;
  width: 24px;
  height: 24px;
  border-radius: 6px;
  background: var(--atlas-sidebar);
  font-size: 10px;
  font-weight: 800;
}

.atlas-learn .tree-item strong {
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
  font-size: 12px;
}

.atlas-learn .tree-item em {
  color: var(--atlas-dim);
  font-size: 11px;
  font-style: normal;
}

.brain-row {
  display: grid;
  grid-template-columns: 58px 1fr;
  gap: 8px;
  padding: 7px 0;
  border-top: 1px solid rgba(201, 208, 218, 0.7);
  font-size: 12px;
}

.brain-row strong {
  color: var(--atlas-dim);
}

.brain-row span {
  color: var(--atlas-ink);
}

.atlas-main {
  flex: 1;
  min-width: 0;
  display: flex;
  flex-direction: column;
  overflow: hidden;
}

.atlas-learn .tabs {
  display: flex;
  align-items: flex-end;
  gap: 2px;
  min-height: 36px;
  padding: 0 8px;
  border-bottom: 1px solid var(--atlas-line);
  background: var(--atlas-panel);
}

.atlas-learn .tab {
  min-height: 35px;
  padding: 0 14px;
  border: 1px solid transparent;
  border-bottom: 0;
  border-radius: 6px 6px 0 0;
  color: var(--atlas-muted);
  background: transparent;
  font-size: 12px;
}

.atlas-learn .tab.active {
  color: var(--atlas-ink);
  border-color: var(--atlas-line);
  background: var(--atlas-bg);
}

.atlas-learn .workspace {
  flex: 1;
  display: grid;
  grid-template-rows: auto minmax(0, 1fr) auto;
  gap: 14px;
  overflow: auto;
  padding: 18px;
}

.workspace-head {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 18px;
}

.workspace-head h1 {
  margin: 0;
  font-size: 28px;
  line-height: 1.16;
}

.workspace-head button,
.atlas-assignment button {
  min-height: 34px;
  padding: 0 13px;
}

.atlas-slide {
  position: relative;
  display: grid;
  align-content: center;
  min-height: 420px;
  padding: 42px;
  border: 1px solid var(--atlas-line);
  border-radius: 10px;
  background: var(--atlas-panel);
}

.atlas-slide p {
  color: var(--atlas-dim);
  font-size: 12px;
  font-weight: 800;
}

.atlas-slide h2 {
  max-width: 760px;
  font-size: 34px;
  line-height: 1.16;
}

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

.atlas-slide-grid div {
  padding: 14px;
  border: 1px solid var(--atlas-line);
  border-radius: 8px;
  background: var(--atlas-bg);
}

.atlas-slide-grid span {
  display: block;
  margin-bottom: 6px;
  color: var(--atlas-dim);
  font-size: 11px;
}

.atlas-slide-grid strong {
  font-size: 13px;
}

.avatar-window {
  position: absolute;
  top: 18px;
  right: 18px;
  display: flex;
  align-items: center;
  gap: 9px;
  min-width: 170px;
  padding: 8px 10px;
  border: 1px solid var(--atlas-line);
  border-radius: 8px;
  background: rgba(255, 255, 255, 0.92);
  box-shadow: 0 10px 26px rgba(25, 32, 42, 0.08);
}

.avatar-face {
  display: grid;
  place-items: end center;
  width: 38px;
  height: 38px;
  border-radius: 50%;
  background: linear-gradient(180deg, #dce3ea, #b8c3cf);
}

.avatar-face span {
  width: 14px;
  height: 4px;
  margin-bottom: 10px;
  border-radius: 999px;
  background: var(--atlas-ink);
  animation: avatar-mouth 1.1s ease-in-out infinite;
}

.avatar-window strong,
.avatar-window em {
  display: block;
  font-size: 12px;
}

.avatar-window em {
  margin-top: 2px;
  color: var(--atlas-dim);
  font-style: normal;
  font-size: 11px;
}

@keyframes avatar-mouth {
  0%,
  100% {
    transform: scaleY(1);
  }
  45% {
    transform: scaleY(2.3);
  }
}

.atlas-assignment {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
  padding: 14px;
  border: 1px solid var(--atlas-line);
  border-radius: 10px;
  background: var(--atlas-panel);
}

.atlas-assignment span {
  color: var(--atlas-dim);
  font-size: 11px;
  font-weight: 800;
}

.atlas-assignment h3 {
  margin: 5px 0 4px;
  font-size: 16px;
}

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

.atlas-right {
  width: 360px;
  flex-shrink: 0;
  display: flex;
  flex-direction: column;
  overflow: hidden;
  border-left: 1px solid var(--atlas-line);
  background: var(--atlas-panel);
}

.right-tabs {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 6px;
  padding: 10px;
  border-bottom: 1px solid var(--atlas-line);
}

.right-tabs button {
  min-height: 30px;
}

.atlas-learn .chat-panel {
  flex: 1;
  display: flex;
  flex-direction: column;
  min-height: 0;
  background: var(--atlas-bg);
}

.atlas-learn .chat-messages {
  flex: 1;
  overflow: auto;
  padding: 12px;
}

.atlas-learn .chat-msg {
  max-width: 92%;
  margin-bottom: 10px;
  padding: 10px 12px;
  border-radius: 12px;
  color: var(--atlas-ink);
  background: var(--atlas-active);
  font-size: 13px;
  line-height: 1.6;
}

.atlas-learn .chat-msg.user {
  margin-left: auto;
  background: var(--atlas-panel);
  border: 1px solid var(--atlas-line);
}

.atlas-learn .chat-msg .label {
  margin-bottom: 4px;
  color: var(--atlas-green);
  font-size: 11px;
  font-weight: 800;
}

.atlas-learn .chat-input-bar {
  display: grid;
  grid-template-columns: 1fr 34px;
  gap: 8px;
  padding: 10px;
  border-top: 1px solid var(--atlas-line);
  background: var(--atlas-panel);
}

.atlas-learn .chat-input-bar textarea {
  min-height: 38px;
  max-height: 90px;
  border: 1px solid var(--atlas-line);
  border-radius: 8px;
  padding: 9px 10px;
  color: var(--atlas-ink);
  background: var(--atlas-active);
  font: inherit;
  font-size: 12px;
  resize: vertical;
}

.atlas-settings {
  padding: 0 12px 12px;
  border-top: 1px solid var(--atlas-line);
  background: var(--atlas-panel);
}

.atlas-settings label {
  display: grid;
  gap: 6px;
  margin-bottom: 10px;
  color: var(--atlas-muted);
  font-size: 12px;
  font-weight: 700;
}

.atlas-settings select {
  width: 100%;
  border: 1px solid var(--atlas-line);
  border-radius: 7px;
  padding: 8px 9px;
  color: var(--atlas-ink);
  background: var(--atlas-bg);
  font: inherit;
  font-size: 12px;
}

.atlas-settings .check-row {
  display: flex;
  align-items: center;
  gap: 8px;
  color: var(--atlas-ink);
}

.platform-main {
  flex: 1;
  min-width: 0;
  overflow: auto;
  padding: 28px;
  background: var(--atlas-bg);
}

.platform-head {
  max-width: 1160px;
  margin: 0 auto 18px;
}

.platform-head span {
  color: var(--atlas-dim);
  font-size: 11px;
  font-weight: 800;
  text-transform: uppercase;
}

.platform-head h1 {
  margin: 6px 0 7px;
  font-size: 28px;
  line-height: 1.18;
}

.platform-head p {
  max-width: 720px;
  margin: 0;
  color: var(--atlas-muted);
  font-size: 13px;
  line-height: 1.65;
}

.platform-grid {
  max-width: 1160px;
  margin: 0 auto 18px;
  display: grid;
  gap: 12px;
}

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

.platform-grid.four {
  grid-template-columns: repeat(4, minmax(0, 1fr));
}

.platform-grid article,
.platform-section,
.settings-grid section {
  border: 1px solid var(--atlas-line);
  border-radius: 8px;
  background: var(--atlas-panel);
}

.platform-grid article {
  padding: 16px;
}

.platform-grid article span,
.course-product span {
  display: block;
  margin-bottom: 9px;
  color: var(--atlas-dim);
  font-size: 11px;
  font-weight: 800;
}

.platform-grid article strong {
  display: block;
  color: var(--atlas-ink);
  font-size: 20px;
  line-height: 1.25;
}

.platform-grid article p,
.course-product p {
  margin: 8px 0 0;
  color: var(--atlas-muted);
  font-size: 12px;
  line-height: 1.6;
}

.platform-section {
  max-width: 1160px;
  margin: 0 auto 18px;
  padding: 16px;
}

.platform-section-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  margin-bottom: 12px;
}

.platform-section-head h2 {
  margin: 0;
  font-size: 16px;
}

.platform-section-head span,
.platform-section-head a {
  color: var(--atlas-dim);
  font-size: 12px;
  font-weight: 700;
}

.platform-section-head a {
  color: var(--atlas-ink);
}

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

.platform-list div,
.schedule-list div,
.api-table div {
  display: grid;
  grid-template-columns: 150px minmax(0, 1fr);
  align-items: center;
  gap: 12px;
  padding: 10px 12px;
  border: 1px solid var(--atlas-line);
  border-radius: 7px;
  background: var(--atlas-bg);
}

.platform-list.compact div {
  grid-template-columns: 132px minmax(0, 1fr);
}

.platform-list strong,
.schedule-list strong {
  font-size: 13px;
}

.platform-list span,
.schedule-list em,
.api-table span {
  color: var(--atlas-muted);
  font-size: 12px;
  font-style: normal;
  line-height: 1.5;
}

.course-product h2 {
  margin: 0;
  font-size: 20px;
}

.course-product.active {
  border-color: rgba(42, 168, 102, 0.45);
}

.course-product button,
.settings-grid button {
  margin-top: 16px;
  min-height: 34px;
  padding: 0 14px;
  border: 1px solid var(--black);
  border-radius: 7px;
  color: #fff;
  background: var(--black);
  font: inherit;
  font-size: 12px;
  font-weight: 800;
}

.settings-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
}

.settings-grid section {
  padding: 14px;
}

.settings-grid h2 {
  margin: 0 0 12px;
  font-size: 15px;
}

.settings-grid label {
  display: grid;
  gap: 6px;
  margin-top: 10px;
  color: var(--atlas-muted);
  font-size: 12px;
  font-weight: 700;
}

.settings-grid input,
.settings-grid select {
  width: 100%;
  min-height: 34px;
  border: 1px solid var(--atlas-line);
  border-radius: 7px;
  padding: 7px 9px;
  color: var(--atlas-ink);
  background: var(--atlas-bg);
  font: inherit;
  font-size: 12px;
}

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

.schedule-list div {
  grid-template-columns: 76px minmax(0, 180px) minmax(0, 1fr);
}

.schedule-list span {
  color: var(--atlas-dim);
  font-size: 12px;
  font-weight: 800;
}

.api-table {
  display: grid;
  gap: 8px;
}

.api-table div {
  grid-template-columns: 70px minmax(190px, 0.6fr) minmax(0, 1fr);
}

.api-table strong {
  color: var(--atlas-ink);
  font-size: 11px;
}

.api-table code,
.api-code {
  font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", monospace;
}

.api-table code {
  overflow: hidden;
  color: var(--atlas-ink);
  font-size: 12px;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.api-code {
  overflow: auto;
  margin: 0;
  padding: 14px;
  border: 1px solid var(--atlas-line);
  border-radius: 8px;
  color: var(--atlas-ink);
  background: var(--atlas-bg);
  font-size: 12px;
  line-height: 1.65;
}

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

.upload-panel label {
  display: grid;
  gap: 6px;
  color: var(--atlas-muted);
  font-size: 12px;
  font-weight: 800;
}

.upload-panel input,
.upload-panel select,
.upload-panel textarea {
  min-height: 34px;
  border: 1px solid var(--atlas-line);
  border-radius: 7px;
  padding: 7px 9px;
  color: var(--atlas-ink);
  background: var(--atlas-bg);
  font: inherit;
  font-size: 12px;
}

.upload-panel textarea {
  min-height: 120px;
  resize: vertical;
}

.upload-panel .upload-drop {
  grid-column: 1 / -1;
  min-height: 86px;
  place-content: center;
  border: 1px dashed var(--atlas-line);
  border-radius: 8px;
  padding: 16px;
  text-align: center;
  background: var(--atlas-bg);
}

.upload-panel .upload-drop input {
  width: min(100%, 420px);
  margin: 6px auto 0;
  background: var(--atlas-panel);
}

.upload-panel button {
  width: fit-content;
  min-height: 34px;
  padding: 0 16px;
  border: 1px solid var(--black);
  border-radius: 7px;
  color: #fff;
  background: var(--black);
  font: inherit;
  font-size: 12px;
  font-weight: 800;
}

.upload-result {
  margin-top: 12px;
  padding: 10px 12px;
  border: 1px solid var(--atlas-line);
  border-radius: 7px;
  color: var(--atlas-muted);
  background: var(--atlas-bg);
  font-size: 12px;
  line-height: 1.6;
}

.login-panel {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 220px)) auto;
  gap: 12px;
  align-items: end;
}

.login-panel label {
  display: grid;
  gap: 6px;
  color: var(--atlas-muted);
  font-size: 12px;
  font-weight: 800;
}

.login-panel input {
  min-height: 34px;
  border: 1px solid var(--atlas-line);
  border-radius: 7px;
  padding: 7px 9px;
  color: var(--atlas-ink);
  background: var(--atlas-bg);
  font: inherit;
  font-size: 12px;
}

.login-panel button {
  min-height: 34px;
  padding: 0 16px;
  border: 1px solid var(--black);
  border-radius: 7px;
  color: #fff;
  background: var(--black);
  font: inherit;
  font-size: 12px;
  font-weight: 800;
}

@media (max-width: 980px) {
  body.atlas-learn {
    display: block;
    height: auto;
    overflow: auto;
  }

  .atlas-learn .activity-bar {
    position: sticky;
    top: 0;
    z-index: 5;
    width: 100%;
    flex-direction: row;
    justify-content: center;
    border-right: 0;
    border-bottom: 1px solid var(--atlas-line);
  }

  .atlas-sidebar,
  .atlas-right {
    width: auto;
    border: 0;
    border-bottom: 1px solid var(--atlas-line);
  }

  .atlas-slide-grid {
    grid-template-columns: 1fr 1fr;
  }

  .platform-grid.two,
  .platform-grid.four,
  .settings-grid {
    grid-template-columns: 1fr;
  }

  .platform-list div,
  .schedule-list div,
  .api-table div,
  .upload-panel,
  .login-panel {
    grid-template-columns: 1fr;
  }
}