.learning-page {
  width: min(calc(100% - 32px), 1660px);
  margin: auto;
  padding-bottom: 72px;
}

.learning-heading {
  display: flex;
  align-items: flex-end;
  justify-content: space-between;
  gap: 32px;
  padding: 48px 0 26px;
}

.learning-heading h1 {
  margin: 8px 0;
  font-size: clamp(42px, 6vw, 70px);
  line-height: 1;
  letter-spacing: -.05em;
}

.learning-heading p {
  max-width: 720px;
  margin: 0;
  color: var(--muted);
}

.learning-heading-note {
  display: grid;
  min-width: 250px;
  gap: 3px;
  padding: 15px 18px;
  border: 1px solid var(--line);
  border-radius: 12px;
  background: #091725;
}

.learning-heading-note strong { color: var(--text); }
.learning-heading-note span { color: var(--muted); font-size: 11px; }

.course-catalog {
  padding: 28px;
  border: 1px solid var(--line);
  border-radius: 18px;
  background: linear-gradient(145deg, #0b1b2b, #07121e);
}

.course-catalog-head,
.course-view-head {
  display: flex;
  align-items: flex-end;
  justify-content: space-between;
  gap: 24px;
}

.course-catalog-head > div > span {
  color: var(--accent);
  font-size: 10px;
  letter-spacing: .15em;
}

.course-catalog-head h2,
.course-view-head h2 {
  margin: 5px 0;
  font-size: 30px;
}

.course-catalog-head p {
  margin: 0;
  color: var(--muted);
}

.course-catalog-head > small {
  padding: 7px 10px;
  border: 1px solid var(--line);
  border-radius: 18px;
  color: var(--muted);
}

.course-card-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 16px;
  margin-top: 24px;
}

.course-select-card {
  position: relative;
  display: grid;
  align-content: start;
  min-height: 310px;
  gap: 15px;
  overflow: hidden;
  padding: 22px;
  border: 1px solid var(--line);
  border-radius: 15px;
  background: #081522;
  color: var(--text);
}

.course-select-card-active {
  border-color: #73d8ff55;
  background: linear-gradient(145deg, #10263a, #081522);
  transition: transform .18s, border-color .18s, box-shadow .18s;
}

.course-select-card-active:hover {
  border-color: var(--accent);
  box-shadow: 0 18px 45px #0006;
  transform: translateY(-3px);
}

.course-card-index {
  position: absolute;
  top: 18px;
  right: 19px;
  color: #73d8ff44;
  font: 800 34px/1 ui-monospace, SFMono-Regular, Menlo, monospace;
}

.course-card-icon {
  width: 52px;
  height: 52px;
  display: grid;
  place-items: center;
  border: 1px solid #73d8ff45;
  border-radius: 13px;
  background: #73d8ff0c;
  color: var(--accent);
  font: 800 15px/1 ui-monospace, SFMono-Regular, Menlo, monospace;
}

.course-select-card small {
  color: var(--accent);
  font-size: 10px;
  letter-spacing: .1em;
}

.course-select-card h3 {
  margin: 6px 0 8px;
  font-size: 24px;
}

.course-select-card p {
  margin: 0;
  color: var(--muted);
  font-size: 13px;
  line-height: 1.65;
}

.course-card-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 7px;
}

.course-card-meta span,
.course-coming {
  width: max-content;
  padding: 4px 8px;
  border: 1px solid var(--line);
  border-radius: 14px;
  color: var(--muted);
  font-size: 10px;
}

.course-card-action {
  align-self: end;
  color: var(--accent);
  font-size: 13px;
}

.course-select-card-planned {
  opacity: .62;
}

.course-coming { margin-top: auto; }

.course-view-head {
  margin-bottom: 18px;
  padding: 18px 20px;
  border: 1px solid var(--line);
  border-radius: 14px;
  background: #071522;
}

.course-view-head h2 { margin-bottom: 0; font-size: 24px; }

.back-to-courses {
  display: inline-block;
  margin-bottom: 11px;
  color: var(--accent);
  font-size: 12px;
}

.course-stats {
  display: grid;
  grid-template-columns: repeat(3, minmax(90px, 1fr));
  min-width: 360px;
  padding: 14px;
}

.course-stats div {
  padding: 4px 16px;
  border-right: 1px solid var(--line);
}

.course-stats div:last-child { border: 0; }
.course-stats strong { display: block; font-size: 23px; }
.course-stats small { color: var(--muted); font-size: 11px; }

.learning-shell {
  display: grid;
  grid-template-columns: 260px minmax(480px, 1fr) minmax(330px, 390px);
  gap: 16px;
  align-items: start;
}

.course-directory,
.code-workspace {
  position: sticky;
  top: 85px;
  max-height: calc(100vh - 102px);
  overflow: auto;
}

.course-directory { padding: 18px; }

.directory-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
}

.directory-head span {
  color: var(--accent);
  font-size: 10px;
  letter-spacing: .16em;
}

.directory-head h2 {
  max-width: 180px;
  margin: 2px 0;
  font-size: 18px;
  line-height: 1.2;
}

.directory-head button {
  display: none;
  padding: 6px 10px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: transparent;
  color: var(--text);
}

.course-directory > progress {
  width: 100%;
  height: 7px;
  margin: 14px 0 2px;
  accent-color: var(--accent2);
}

.course-directory > small { color: var(--muted); font-size: 11px; }

.chapter-list {
  display: grid;
  gap: 10px;
  margin-top: 18px;
}

.course-chapter {
  padding-top: 10px;
  border-top: 1px solid var(--line);
}

.course-chapter summary {
  display: flex;
  justify-content: space-between;
  gap: 8px;
  list-style: none;
  cursor: pointer;
}

.course-chapter summary::-webkit-details-marker { display: none; }
.course-chapter summary span { color: var(--accent); font-size: 10px; }
.course-chapter summary strong { display: block; font-size: 13px; }
.course-chapter summary small { color: var(--muted); }

.chapter-lessons {
  display: grid;
  gap: 3px;
  margin-top: 8px;
}

.lesson-link {
  width: 100%;
  display: grid;
  grid-template-columns: 20px 1fr;
  align-items: start;
  gap: 6px;
  padding: 8px 6px;
  border: 0;
  border-radius: 8px;
  background: transparent;
  color: var(--muted);
  text-align: left;
  cursor: pointer;
  font-size: 12px;
}

.lesson-link:hover,
.lesson-link.active { background: #13263a; color: var(--text); }
.lesson-link .lesson-state { color: var(--accent2); }

.lesson-stage {
  min-width: 0;
  min-height: 760px;
  padding: 34px;
}

.lesson-kicker {
  display: flex;
  align-items: center;
  gap: 10px;
  color: var(--accent);
  font-size: 11px;
  letter-spacing: .12em;
}

.lesson-kicker span:last-child {
  padding-left: 10px;
  border-left: 1px solid var(--line);
  color: var(--muted);
  letter-spacing: 0;
}

.lesson-stage h2 {
  margin: 13px 0;
  font-size: clamp(28px, 4vw, 42px);
  line-height: 1.08;
}

.lesson-summary {
  margin-bottom: 30px;
  color: var(--muted);
  font-size: 17px;
}

.lesson-block { margin: 21px 0; }
.lesson-block p { color: #c7d7e7; line-height: 1.75; }

.lesson-topic {
  margin: 24px 0 10px;
  padding-top: 4px;
}

.lesson-topic h3 {
  margin: 0 0 7px;
  color: #e9f5ff;
  font-size: 18px;
  line-height: 1.25;
}

.lesson-topic p { margin: 0; color: #c7d7e7; line-height: 1.75; }
.lesson-topic + .lesson-code { margin-top: 12px; }

.lesson-code {
  position: relative;
  margin: 22px 0;
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: 13px;
  background: #06101a;
}

.lesson-code pre {
  margin: 0;
  overflow: auto;
  padding: 48px 20px 20px;
  color: #dff4ff;
  font: 13px/1.7 ui-monospace, SFMono-Regular, Menlo, monospace;
}

.try-code {
  position: absolute;
  z-index: 1;
  top: 9px;
  right: 9px;
  padding: 6px 9px;
  border: 1px solid var(--line);
  border-radius: 7px;
  background: #10243a;
  color: var(--accent);
  cursor: pointer;
  font-size: 11px;
}

.lesson-tip {
  padding: 14px 16px;
  border-left: 3px solid var(--accent);
  border-radius: 0 10px 10px 0;
  background: #0a1928;
  color: #bdd1e3;
}

.lesson-assignment {
  margin: 34px 0 24px;
  overflow: hidden;
  border: 1px solid #73d8ff55;
  border-radius: 15px;
  background: linear-gradient(145deg, #0b1d2f, #0a1725);
}

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

.assignment-head h3 { margin: 3px 0; font-size: 20px; }
.assignment-head p { margin: 5px 0 0; color: var(--muted); font-size: 13px; }
.assignment-badge { color: var(--accent); font-size: 10px; letter-spacing: .14em; }

.submission-records {
  padding: 16px 20px;
  border-top: 1px solid var(--line);
}

.records-title {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  margin-bottom: 9px;
}

.records-title strong { font-size: 13px; }
.records-title small { color: var(--muted); }
.record-list { display: grid; gap: 7px; }

.submission-row {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  align-items: center;
  gap: 10px;
  padding: 10px 0;
  border-bottom: 1px solid #20364c88;
}

.submission-row:last-child { border: 0; }
.submission-row strong,
.submission-row small { display: block; }
.submission-row small { color: var(--muted); font-size: 11px; }

.record-metrics { display: flex; align-items: center; gap: 7px; }
.record-metrics span { padding: 3px 6px; border: 1px solid var(--line); border-radius: 12px; color: var(--muted); font-size: 10px; }
.record-pass { color: var(--accent2) !important; }
.record-fail { color: var(--danger) !important; }
.visibility-button { border: 0; background: none; color: var(--accent); cursor: pointer; font-size: 11px; }

.lesson-footer {
  display: grid;
  gap: 14px;
  margin-top: 34px;
  padding-top: 24px;
  border-top: 1px solid var(--line);
}

.lesson-notes { resize: vertical; }
.lesson-notes-label { display: flex; align-items: center; gap: 9px; }
.lesson-notes-label small {
  padding: 3px 7px;
  border: 1px solid var(--line);
  border-radius: 999px;
  color: var(--muted);
  font-size: 10px;
  font-weight: 600;
}
.draft-library-item .draft-library-actions { flex-wrap: wrap; }
.lesson-navigation { display: flex; justify-content: space-between; gap: 10px; }

@media (max-width: 760px) {
  .draft-library-item .draft-library-actions { grid-template-columns: repeat(auto-fit, minmax(110px, 1fr)); }
}

.code-workspace { min-width: 0; padding: 18px; }

.workspace-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-bottom: 14px;
  border-bottom: 1px solid var(--line);
}

.workspace-head > div { display: flex; align-items: center; gap: 10px; }
.workspace-head small,
.workspace-head strong { display: block; }
.workspace-head small { color: var(--muted); font-size: 10px; }

.status-dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: #718096;
  box-shadow: 0 0 0 5px #71809622;
}

.status-dot.online { background: var(--accent2); box-shadow: 0 0 0 5px #9ef0cb22; }

.workspace-expand {
  width: 34px;
  height: 34px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: transparent;
  color: var(--accent);
  cursor: pointer;
}

.workspace-limits { display: flex; flex-wrap: wrap; gap: 6px; margin: 12px 0; }
.workspace-limits span { padding: 3px 7px; border: 1px solid var(--line); border-radius: 12px; color: var(--muted); font-size: 10px; }
.editor-label { display: flex; justify-content: space-between; margin: 13px 0 7px; font-size: 12px; }
.editor-label small { color: var(--muted); }

.code-editor {
  min-height: 280px;
  resize: vertical;
  border-radius: 11px;
  background: #050d16;
  color: #dff4ff;
  font: 13px/1.65 ui-monospace, SFMono-Regular, Menlo, monospace;
  tab-size: 4;
}

.workspace-actions { display: grid; grid-template-columns: 1fr auto; gap: 8px; margin-top: 9px; }
.workspace-actions button:disabled { opacity: .45; cursor: not-allowed; }
.run-metrics { min-height: 30px; display: flex; align-items: end; gap: 7px; }
.run-metrics span { padding: 3px 7px; border-radius: 12px; background: #102238; color: var(--muted); font-size: 10px; }

.run-output {
  min-height: 110px;
  max-height: 220px;
  margin: 8px 0;
  overflow: auto;
  padding: 13px;
  border: 1px solid var(--line);
  border-radius: 10px;
  background: #050d16;
  color: #bfe8d8;
  white-space: pre-wrap;
  word-break: break-word;
  font: 12px/1.55 ui-monospace, SFMono-Regular, Menlo, monospace;
}

.workspace-notice { min-height: 20px; }
.workspace-footer { display: flex; justify-content: space-between; gap: 10px; padding-top: 12px; border-top: 1px solid var(--line); }
.workspace-footer span { color: var(--muted); font-size: 9px; }
.text-button { padding: 0; border: 0; background: none; color: var(--muted); cursor: pointer; font-size: 10px; }
.text-button:hover { color: var(--danger); }

@media (max-width: 1280px) {
  .learning-shell { grid-template-columns: 230px minmax(420px, 1fr) minmax(300px, 340px); }
  .lesson-stage { padding: 28px; }
}

@media (max-width: 1100px) {
  .course-card-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .learning-shell { grid-template-columns: 235px minmax(0, 1fr); }
  .course-directory { grid-row: 1 / 3; }
  .code-workspace { position: relative; top: auto; grid-column: 2; max-height: none; }
  .code-editor { min-height: 230px; }
}

@media (max-width: 820px) {
  .learning-page { width: min(calc(100% - 24px), 1660px); }
  .learning-heading,
  .course-view-head { align-items: stretch; flex-direction: column; }
  .learning-heading-note { min-width: 0; }
  .course-stats { width: 100%; min-width: 0; }
  .course-card-grid { grid-template-columns: 1fr; }
  .course-select-card { min-height: 260px; }
  .learning-shell { display: block; }
  .course-directory,
  .code-workspace { position: relative; top: auto; max-height: none; margin-bottom: 14px; }
  .directory-head button { display: block; }
  .chapter-list.collapsed { display: none; }
  .lesson-stage { min-height: 0; margin-bottom: 14px; padding: 22px; }
  .assignment-head { align-items: stretch; flex-direction: column; }
  .submission-row { grid-template-columns: 1fr; }
  .record-metrics { flex-wrap: wrap; }
  .lesson-navigation .button { padding: 9px; font-size: 12px; }
}

@media (max-width: 520px) {
  .learning-heading { padding-top: 34px; }
  .course-catalog { padding: 18px; }
  .course-catalog-head { align-items: flex-start; flex-direction: column; }
  .course-stats { padding: 12px; }
  .course-stats div { padding: 2px 9px; }
  .course-stats strong { font-size: 18px; }
  .lesson-stage { padding: 18px; }
  .lesson-stage h2 { font-size: 30px; }
  .lesson-navigation { flex-direction: column; }
  .workspace-actions { grid-template-columns: 1fr; }
  .workspace-footer { display: block; }
  .workspace-footer span { display: block; margin-top: 5px; }
}