.python-hero {
  position: relative;
  isolation: isolate;
  overflow: hidden;
  background:
    radial-gradient(circle at 82% 10%, rgba(255, 209, 102, .2), transparent 25rem),
    radial-gradient(circle at 12% 88%, rgba(6, 214, 160, .13), transparent 28rem),
    var(--navy);
  color: var(--surface);
}

.python-hero::after {
  position: absolute;
  z-index: -1;
  inset: 0;
  background-image:
    linear-gradient(rgba(255,255,255,.035) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255,255,255,.035) 1px, transparent 1px);
  background-size: 46px 46px;
  content: "";
  mask-image: linear-gradient(to bottom, black, transparent 88%);
}

.python-hero-inner {
  width: min(1180px, calc(100% - 48px));
  min-height: 620px;
  margin: 0 auto;
  padding: 88px 0;
  display: grid;
  grid-template-columns: minmax(0, 1.15fr) minmax(320px, .85fr);
  gap: clamp(48px, 8vw, 100px);
  align-items: center;
}

.python-hero .eyebrow,
.lesson-hero .eyebrow {
  color: var(--gold);
}

.python-hero h1,
.lesson-hero h1 {
  margin: 0;
  font-family: Georgia, "Times New Roman", serif;
  font-weight: 400;
  letter-spacing: -.05em;
}

.python-hero h1 {
  max-width: 780px;
  font-size: clamp(52px, 7.2vw, 94px);
  line-height: .97;
}

.python-hero-copy > p:not(.eyebrow) {
  max-width: 690px;
  margin: 30px 0 0;
  color: rgba(255,255,255,.76);
  font-size: clamp(17px, 1.6vw, 21px);
}

.hero-actions {
  margin-top: 38px;
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.python-button {
  min-height: 48px;
  padding: 12px 18px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 20px;
  border: 1px solid transparent;
  border-radius: 9px;
  font-weight: 700;
  text-decoration: none;
  transition: transform 160ms ease, background 160ms ease;
}

.python-button:hover {
  transform: translateY(-2px);
}

.python-button.primary {
  background: var(--gold);
  color: var(--navy-deep);
}

.python-button.secondary {
  border-color: rgba(255,255,255,.3);
  color: var(--surface);
}

.python-button.secondary:hover {
  background: rgba(255,255,255,.08);
}

.python-terminal {
  overflow: hidden;
  border: 1px solid rgba(255,255,255,.14);
  border-radius: 16px;
  background: rgba(4,45,59,.82);
  box-shadow: 0 30px 80px rgba(0,0,0,.28);
  transform: rotate(1.5deg);
}

.terminal-bar {
  height: 44px;
  padding: 0 16px;
  display: flex;
  align-items: center;
  gap: 8px;
  border-bottom: 1px solid rgba(255,255,255,.1);
  background: rgba(255,255,255,.04);
}

.terminal-bar span {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: var(--coral);
}

.terminal-bar span:nth-child(2) { background: var(--gold); }
.terminal-bar span:nth-child(3) { background: var(--mint); }

.python-terminal pre {
  margin: 0;
  padding: 30px 28px 36px;
  overflow: auto;
  color: #e9f6f3;
  font: 14px/1.75 ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
}

.terminal-prompt { color: var(--mint); }

.course-intro,
.modules-section,
.study-callout {
  width: min(1180px, calc(100% - 48px));
  margin: 0 auto;
}

.course-intro {
  padding: 105px 0;
  display: grid;
  grid-template-columns: .8fr 1.2fr;
  gap: clamp(40px, 8vw, 110px);
}

.course-intro h2,
.section-heading h2,
.study-callout h2 {
  margin: 0;
  color: var(--navy);
  font-family: Georgia, "Times New Roman", serif;
  font-size: clamp(40px, 5vw, 66px);
  font-weight: 400;
  line-height: 1.03;
  letter-spacing: -.04em;
}

.course-intro-copy > p {
  margin: 0;
  font-size: 19px;
}

.course-facts {
  margin: 38px 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 18px;
  list-style: none;
}

.course-facts li {
  padding-top: 16px;
  border-top: 3px solid var(--gold);
}

.course-facts strong,
.course-facts span {
  display: block;
}

.course-facts strong {
  color: var(--navy);
  font-size: 24px;
}

.course-facts span {
  color: var(--muted);
  font-size: 13px;
}

.modules-section {
  padding: 0 0 110px;
}

.section-heading {
  max-width: 720px;
  margin-bottom: 45px;
}

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

.module-card {
  min-height: 188px;
  padding: 26px;
  display: grid;
  grid-template-columns: 54px 1fr auto;
  gap: 18px;
  border: 1px solid var(--line);
  border-radius: 16px;
  background: var(--surface);
  box-shadow: 0 12px 34px rgba(4,45,59,.05);
  transition: border 160ms ease, transform 160ms ease, box-shadow 160ms ease;
}

.module-card:hover {
  border-color: rgba(7,59,76,.32);
  box-shadow: 0 18px 42px rgba(4,45,59,.09);
  transform: translateY(-3px);
}

.module-number {
  color: var(--coral);
  font-family: "Rubik Mono One", monospace;
  font-size: 20px;
}

.module-duration {
  margin: 0 0 9px;
  color: var(--muted);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: .06em;
  text-transform: uppercase;
}

.module-card h3 {
  margin: 0;
  color: var(--navy);
  font-size: 21px;
}

.module-card h3 a { text-decoration: none; }
.module-card-copy > p:last-child { margin: 10px 0 0; color: var(--muted); }

.module-arrow {
  width: 38px;
  height: 38px;
  display: grid;
  border: 1px solid var(--line);
  border-radius: 50%;
  color: var(--navy);
  text-decoration: none;
  place-items: center;
}

.study-callout {
  margin-bottom: 110px;
  padding: clamp(34px, 6vw, 64px);
  display: flex;
  align-items: end;
  justify-content: space-between;
  gap: 40px;
  border-radius: 20px;
  background: var(--navy);
  color: var(--surface);
}

.study-callout h2 { color: var(--surface); }
.study-callout > div > p:last-child { max-width: 710px; color: rgba(255,255,255,.73); }
.python-footer { margin-top: 0; }

.lesson-hero {
  background:
    radial-gradient(circle at 88% 0%, rgba(255,209,102,.17), transparent 22rem),
    var(--navy);
  color: var(--surface);
}

.lesson-hero-inner {
  width: min(1180px, calc(100% - 48px));
  margin: 0 auto;
  padding: 72px 0 66px;
}

.lesson-hero h1 {
  max-width: 900px;
  font-size: clamp(46px, 6vw, 80px);
  line-height: 1;
}

.lesson-hero-inner > p:not(.eyebrow) {
  max-width: 760px;
  margin: 22px 0 0;
  color: rgba(255,255,255,.75);
  font-size: 18px;
}

.lesson-meta {
  margin-top: 28px;
  display: flex;
  gap: 12px 24px;
  flex-wrap: wrap;
  color: rgba(255,255,255,.68);
  font-size: 13px;
  font-weight: 700;
  letter-spacing: .06em;
  text-transform: uppercase;
}

.lesson-meta a {
  color: var(--gold);
  text-decoration: none;
}

.lesson-layout {
  width: min(1320px, calc(100% - 48px));
  margin: 0 auto;
  padding: 54px 0 90px;
  display: grid;
  grid-template-columns: 250px minmax(0, 860px);
  gap: clamp(38px, 6vw, 78px);
  justify-content: center;
  align-items: start;
}

.course-sidebar {
  position: sticky;
  top: 102px;
}

.course-home-link {
  display: inline-block;
  margin-bottom: 15px;
  color: var(--muted);
  font-size: 13px;
  font-weight: 700;
  text-decoration: none;
}

.course-sidebar nav {
  display: grid;
  border-top: 1px solid var(--line);
}

.course-sidebar nav a {
  padding: 12px 8px;
  display: grid;
  grid-template-columns: 30px 1fr;
  gap: 8px;
  border-bottom: 1px solid var(--line);
  color: var(--muted);
  font-size: 13px;
  font-weight: 600;
  text-decoration: none;
}

.course-sidebar nav a span {
  color: var(--coral);
  font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
}

.course-sidebar nav a[aria-current="page"] {
  border-radius: 7px;
  background: rgba(255,209,102,.18);
  color: var(--navy);
}

.notebook-content { min-width: 0; }
.markdown-cell { font-size: 17px; }
.markdown-cell:first-child > :first-child { margin-top: 0; }

.markdown-cell h2 {
  margin: 68px 0 20px;
  padding-top: 6px;
  color: var(--navy);
  font-family: Georgia, "Times New Roman", serif;
  font-size: clamp(32px, 4vw, 46px);
  font-weight: 400;
  line-height: 1.08;
  letter-spacing: -.035em;
}

.markdown-cell h3 {
  margin: 40px 0 14px;
  color: var(--navy);
}

.markdown-cell p,
.markdown-cell li { max-width: 78ch; }

.markdown-cell blockquote {
  margin: 26px 0;
  padding: 17px 20px;
  border-left: 4px solid var(--gold);
  background: rgba(255,209,102,.1);
}

.markdown-cell table {
  width: 100%;
  margin: 24px 0;
  border-collapse: collapse;
  background: var(--surface);
}

.markdown-cell th,
.markdown-cell td {
  padding: 11px 13px;
  border: 1px solid var(--line);
  text-align: left;
}

.markdown-cell th {
  background: var(--navy);
  color: var(--surface);
}

.markdown-cell code:not(pre code) {
  padding: 2px 6px;
  border-radius: 5px;
  background: rgba(7,59,76,.08);
  color: #a63e3e;
  font: .9em ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
}

.code-cell {
  margin: 24px 0 34px;
  overflow: hidden;
  border: 1px solid rgba(7,59,76,.18);
  border-radius: 13px;
  background: #082f3b;
  box-shadow: 0 12px 28px rgba(4,45,59,.08);
}

.exercise-cell { border-color: rgba(255,107,107,.55); }

.code-cell-toolbar {
  min-height: 40px;
  padding: 7px 10px 7px 16px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  border-bottom: 1px solid rgba(255,255,255,.09);
  color: rgba(255,255,255,.65);
  font-size: 11px;
  font-weight: 700;
  letter-spacing: .08em;
  text-transform: uppercase;
}

.code-cell-toolbar button {
  padding: 5px 9px;
  border: 1px solid rgba(255,255,255,.16);
  border-radius: 6px;
  background: transparent;
  color: rgba(255,255,255,.75);
  cursor: pointer;
  font-size: 11px;
  letter-spacing: 0;
  text-transform: none;
}

.code-source { overflow: auto; }
.code-source .highlight { min-width: max-content; }

.code-source pre {
  margin: 0;
  padding: 20px;
  color: #eef7f5;
  font: 13.5px/1.65 ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  tab-size: 4;
}

.cell-output {
  padding: 0 20px 20px;
  background: var(--surface);
}

.cell-output-label {
  padding: 11px 0 8px;
  color: var(--muted);
  font-size: 10px;
  font-weight: 700;
  letter-spacing: .08em;
  text-transform: uppercase;
}

.cell-output-text,
.cell-output-error {
  margin: 0;
  padding: 14px 16px;
  overflow: auto;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #f4f6f5;
  color: var(--ink);
  font: 13px/1.55 ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
}

.cell-output-error { border-color: #eaa; color: #8b2424; }

.cell-output-figure {
  margin: 0;
  padding: 16px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #fff;
}

.cell-output-figure img {
  width: auto;
  max-width: 100%;
  margin: 0 auto;
}

.solution-block {
  margin: 28px 0 42px;
  border: 1px solid rgba(6,214,160,.45);
  border-radius: 13px;
  background: rgba(6,214,160,.05);
}

.solution-block > summary {
  padding: 15px 18px;
  color: var(--navy);
  cursor: pointer;
  font-weight: 700;
}

.solution-block .code-cell {
  margin: 0;
  border: 0;
  border-top: 1px solid rgba(6,214,160,.3);
  border-radius: 0 0 12px 12px;
  box-shadow: none;
}

.lesson-pagination {
  margin-top: 76px;
  padding-top: 28px;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
  border-top: 1px solid var(--line);
}

.lesson-pagination a {
  padding: 18px;
  display: grid;
  border: 1px solid var(--line);
  border-radius: 11px;
  color: var(--navy);
  text-decoration: none;
}

.lesson-pagination a.next { text-align: right; }
.lesson-pagination span { color: var(--muted); font-size: 12px; }

@media (max-width: 900px) {
  .python-hero-inner,
  .course-intro { grid-template-columns: 1fr; }
  .python-hero-inner { min-height: auto; }
  .python-terminal { max-width: 620px; transform: none; }
  .module-grid { grid-template-columns: 1fr; }
  .lesson-layout { grid-template-columns: 1fr; }
  .course-sidebar { position: static; }
  .course-sidebar nav {
    grid-template-columns: repeat(3, 1fr);
    gap: 5px;
    border: 0;
  }
  .course-sidebar nav a {
    grid-template-columns: 26px 1fr;
    border: 1px solid var(--line);
    border-radius: 7px;
  }
}

@media (max-width: 660px) {
  .python-hero-inner,
  .course-intro,
  .modules-section,
  .study-callout,
  .lesson-hero-inner,
  .lesson-layout {
    width: min(100% - 28px, 1180px);
  }
  .python-hero-inner { padding: 62px 0; }
  .python-hero h1 { font-size: clamp(44px, 14vw, 66px); }
  .course-intro { padding: 72px 0; }
  .course-facts { grid-template-columns: 1fr; }
  .module-card { grid-template-columns: 42px 1fr; }
  .module-arrow { display: none; }
  .study-callout { align-items: stretch; flex-direction: column; }
  .course-sidebar nav { grid-template-columns: 1fr; }
  .lesson-pagination { grid-template-columns: 1fr; }
  .lesson-pagination a.next { text-align: left; }
  .markdown-cell { font-size: 16px; }
}