:root {
  --ink: #172337;
  --muted: #657287;
  --line: #dce4ee;
  --surface: #ffffff;
  --surface-soft: #f5f7fb;
  --navy: #0b1930;
  --blue: #3156d8;
  --blue-soft: #edf1ff;
  --cyan: #32d5c8;
  --green: #14866d;
  --red: #b42318;
  --code: #0c1729;
  --radius: 1rem;
  --shadow: 0 18px 55px rgba(18, 32, 51, 0.08);
  --sidebar: 19rem;
  --reading: 52rem;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  color: var(--ink);
  background: var(--surface-soft);
  font-family:
    Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI",
    sans-serif;
  line-height: 1.7;
}

a {
  color: var(--blue);
}

.skip-link {
  position: fixed;
  z-index: 100;
  top: 0.75rem;
  left: 0.75rem;
  padding: 0.65rem 1rem;
  color: #fff;
  background: var(--blue);
  border-radius: 0.6rem;
  transform: translateY(-160%);
}

.skip-link:focus {
  transform: translateY(0);
}

.reader-header {
  position: sticky;
  z-index: 20;
  top: 0;
  display: flex;
  gap: 2rem;
  align-items: center;
  justify-content: space-between;
  min-height: 4.6rem;
  padding: 0.75rem clamp(1rem, 4vw, 3rem);
  background: rgba(255, 255, 255, 0.94);
  border-bottom: 1px solid var(--line);
  backdrop-filter: blur(1rem);
}

.reader-brand {
  display: inline-flex;
  gap: 0.75rem;
  align-items: center;
  color: var(--ink);
  text-decoration: none;
}

.reader-brand > span:first-child {
  display: grid;
  width: 2.5rem;
  height: 2.5rem;
  color: #fff;
  background: linear-gradient(135deg, var(--blue), var(--cyan));
  border-radius: 0.75rem;
  place-items: center;
  font-size: 0.78rem;
  font-weight: 900;
  box-shadow: 0 0.5rem 1.4rem rgba(49, 86, 216, 0.22);
}

.reader-brand strong,
.reader-brand small {
  display: block;
}

.reader-brand strong {
  font-size: 0.9rem;
  line-height: 1.2;
}

.reader-brand small {
  margin-top: 0.1rem;
  color: var(--muted);
  font-size: 0.68rem;
}

.reader-progress {
  display: grid;
  width: min(17rem, 35vw);
  gap: 0.35rem;
}

.reader-progress > span {
  color: var(--muted);
  font-size: 0.7rem;
  font-weight: 750;
  text-align: right;
}

.reader-progress [role="progressbar"] {
  height: 0.4rem;
  overflow: hidden;
  background: #e5eaf1;
  border-radius: 999px;
}

.reader-progress [role="progressbar"] span {
  display: block;
  height: 100%;
  background: linear-gradient(90deg, var(--blue), var(--cyan));
  border-radius: inherit;
}

.reader-layout {
  display: grid;
  grid-template-columns: var(--sidebar) minmax(0, 1fr);
  max-width: 100rem;
  min-height: calc(100vh - 4.6rem);
  margin-inline: auto;
}

.reader-sidebar {
  position: sticky;
  top: 4.6rem;
  height: calc(100vh - 4.6rem);
  padding: 2rem 1.25rem;
  overflow-y: auto;
  background: var(--navy);
}

.sidebar-block + .sidebar-block {
  margin-top: 2rem;
  padding-top: 1.5rem;
  border-top: 1px solid rgba(255, 255, 255, 0.1);
}

.sidebar-label {
  margin: 0 0 0.4rem;
  color: #72e9df;
  font-size: 0.67rem;
  font-weight: 850;
  letter-spacing: 0.13em;
  text-transform: uppercase;
}

.reader-sidebar h2 {
  margin: 0 0 1.2rem;
  color: #fff;
  font-size: 1.2rem;
  line-height: 1.25;
}

.sidebar-heading {
  margin: 0 0 0.8rem;
  color: #fff;
  font-size: 0.92rem;
  font-weight: 800;
  line-height: 1.25;
}

.module-navigation {
  display: grid;
  gap: 0.3rem;
  margin: 0;
  padding: 0;
  list-style: none;
}

.module-navigation a {
  display: grid;
  grid-template-columns: 2rem minmax(0, 1fr);
  gap: 0.55rem;
  align-items: center;
  padding: 0.6rem 0.65rem;
  color: #aebdd1;
  border: 1px solid transparent;
  border-radius: 0.65rem;
  text-decoration: none;
}

.module-navigation a > span {
  color: #70839d;
  font-size: 0.64rem;
  font-weight: 850;
}

.module-navigation a > strong {
  font-size: 0.7rem;
  line-height: 1.25;
}

.module-navigation a:hover,
.module-navigation a:focus-visible {
  color: #fff;
  background: rgba(255, 255, 255, 0.07);
}

.module-navigation a[aria-current="location"] {
  color: #fff;
  background: rgba(50, 213, 200, 0.12);
  border-color: rgba(50, 213, 200, 0.18);
}

.module-navigation a[aria-current="location"] > span {
  color: var(--cyan);
}

.lesson-navigation,
.sidebar-toc ol {
  display: grid;
  gap: 0.25rem;
  margin: 0;
  padding: 0;
  list-style: none;
}

.lesson-navigation a {
  display: grid;
  grid-template-columns: 2.1rem 1fr;
  gap: 0.6rem;
  align-items: center;
  padding: 0.65rem 0.7rem;
  color: #b7c4d7;
  border-radius: 0.65rem;
  font-size: 0.77rem;
  font-weight: 650;
  line-height: 1.3;
  text-decoration: none;
}

.lesson-navigation a span {
  color: #7f91aa;
  font-size: 0.66rem;
  font-weight: 850;
}

.lesson-navigation a:hover,
.lesson-navigation a:focus-visible {
  color: #fff;
  background: rgba(255, 255, 255, 0.07);
}

.lesson-navigation a[aria-current="page"] {
  color: #fff;
  background: rgba(50, 213, 200, 0.13);
  box-shadow: inset 3px 0 var(--cyan);
}

.lesson-navigation a[aria-current="page"] span {
  color: var(--cyan);
}

.sidebar-toc a {
  display: block;
  padding: 0.35rem 0.55rem;
  color: #8798b0;
  font-size: 0.7rem;
  line-height: 1.35;
  text-decoration: none;
}

.sidebar-toc a:hover,
.sidebar-toc a:focus-visible {
  color: #fff;
}

.reader-main {
  width: 100%;
  min-width: 0;
  background: var(--surface);
}

.mobile-course-nav {
  display: none;
}

.lesson-hero {
  display: flex;
  gap: 2rem;
  align-items: end;
  justify-content: space-between;
  padding: clamp(3.5rem, 8vw, 6.5rem) clamp(1.5rem, 7vw, 7rem);
  color: #fff;
  background:
    radial-gradient(circle at 86% 18%, rgba(50, 213, 200, 0.2), transparent 24%),
    radial-gradient(circle at 10% 100%, rgba(49, 86, 216, 0.4), transparent 32%),
    var(--navy);
}

.lesson-kicker {
  margin: 0 0 1rem;
  color: #82eee5;
  font-size: 0.73rem;
  font-weight: 850;
  letter-spacing: 0.13em;
  text-transform: uppercase;
}

.lesson-hero h1 {
  max-width: 15ch;
  margin: 0;
  font-size: clamp(2.4rem, 6vw, 4.8rem);
  line-height: 1;
  letter-spacing: -0.055em;
}

.lesson-meta {
  display: flex;
  gap: 0.5rem 1.2rem;
  margin-top: 1.5rem;
  color: #b9c6d8;
  font-size: 0.76rem;
  flex-wrap: wrap;
}

.lesson-meta span + span::before {
  margin-right: 1.2rem;
  color: #52627a;
  content: "•";
}

.source-link {
  flex: 0 0 auto;
  padding: 0.65rem 0.9rem;
  color: #d4deeb;
  border: 1px solid rgba(255, 255, 255, 0.18);
  border-radius: 999px;
  font-size: 0.72rem;
  font-weight: 750;
  text-decoration: none;
}

.source-link:hover,
.source-link:focus-visible {
  color: #fff;
  border-color: var(--cyan);
}

.lesson-content {
  width: min(calc(100% - 3rem), var(--reading));
  margin-inline: auto;
  padding-block: clamp(3rem, 7vw, 6rem);
}

.lesson-content > *:first-child {
  margin-top: 0;
}

.lesson-content h2,
.lesson-content h3,
.lesson-content h4 {
  color: var(--ink);
  line-height: 1.2;
  scroll-margin-top: 6rem;
}

.lesson-content h2 {
  margin: 4.2rem 0 1rem;
  padding-top: 1rem;
  font-size: clamp(1.65rem, 4vw, 2.25rem);
  letter-spacing: -0.035em;
  border-top: 1px solid var(--line);
}

.lesson-content h2#introducao {
  margin-top: 0;
  padding-top: 0;
  border-top: 0;
}

.lesson-content h2#introducao::before {
  display: block;
  margin-bottom: 0.55rem;
  color: var(--blue);
  content: "Comece por aqui";
  font-size: 0.68rem;
  font-weight: 850;
  letter-spacing: 0.13em;
  text-transform: uppercase;
}

.lesson-content h3 {
  margin: 2.4rem 0 0.7rem;
  font-size: 1.25rem;
}

.lesson-content h4 {
  margin: 1.8rem 0 0.6rem;
  font-size: 1rem;
}

.lesson-content p,
.lesson-content li {
  color: #3e4d62;
}

.lesson-content p {
  margin: 0.85rem 0;
}

.lesson-content ul,
.lesson-content ol {
  padding-left: 1.4rem;
}

.lesson-content li + li {
  margin-top: 0.35rem;
}

.lesson-content strong {
  color: var(--ink);
}

.lesson-content a {
  font-weight: 700;
  text-underline-offset: 0.18em;
}

.lesson-content blockquote {
  margin: 1.75rem 0;
  padding: 1.1rem 1.25rem;
  color: #27415e;
  background: #eff8f7;
  border-left: 4px solid var(--cyan);
  border-radius: 0 var(--radius) var(--radius) 0;
}

.lesson-content blockquote p {
  margin: 0;
  color: inherit;
  font-size: 1.04rem;
  font-weight: 650;
}

.lesson-content code {
  padding: 0.15em 0.35em;
  color: #253faf;
  background: var(--blue-soft);
  border-radius: 0.35rem;
  font-family: "Cascadia Code", "SFMono-Regular", Consolas, monospace;
  font-size: 0.88em;
}

.lesson-content pre {
  position: relative;
  margin: 1.4rem 0;
  padding: 1.2rem 1.3rem;
  overflow-x: auto;
  color: #dce7f7;
  background: var(--code);
  border: 1px solid #1d2c43;
  border-radius: var(--radius);
  box-shadow: 0 0.8rem 2rem rgba(12, 23, 41, 0.12);
}

.lesson-content pre code {
  padding: 0;
  color: inherit;
  background: transparent;
  font-size: 0.82rem;
  line-height: 1.6;
}

.lesson-content table {
  width: 100%;
  margin: 1.5rem 0;
  border-collapse: separate;
  border-spacing: 0;
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: var(--radius);
}

.lesson-content th,
.lesson-content td {
  padding: 0.7rem 0.8rem;
  border-right: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  text-align: left;
  vertical-align: top;
}

.lesson-content th:last-child,
.lesson-content td:last-child {
  border-right: 0;
}

.lesson-content tr:last-child td {
  border-bottom: 0;
}

.lesson-content th {
  color: var(--ink);
  background: var(--surface-soft);
  font-size: 0.76rem;
}

.lesson-content td {
  color: #405069;
  font-size: 0.82rem;
}

.lesson-content input[type="checkbox"] {
  width: 1rem;
  height: 1rem;
  margin: 0 0.35rem 0 0;
  accent-color: var(--blue);
}

.lesson-content hr {
  margin: 3rem 0;
  border: 0;
  border-top: 1px solid var(--line);
}

.pager {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1rem;
  width: min(calc(100% - 3rem), var(--reading));
  margin: 0 auto 4rem;
}

.pager__link {
  display: grid;
  gap: 0.35rem;
  padding: 1rem 1.1rem;
  color: var(--ink);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  text-decoration: none;
}

.pager__link--next {
  text-align: right;
}

.pager__link small {
  color: var(--muted);
  font-size: 0.68rem;
}

.pager__link strong {
  font-size: 0.82rem;
}

.pager__link:hover,
.pager__link:focus-visible {
  border-color: #aebce8;
  box-shadow: var(--shadow);
}

.lesson-footer {
  display: flex;
  gap: 1rem;
  align-items: center;
  justify-content: space-between;
  padding: 1.4rem clamp(1.5rem, 7vw, 7rem);
  color: #94a1b4;
  background: var(--navy);
  font-size: 0.72rem;
}

.lesson-footer p {
  margin: 0;
}

.lesson-footer a {
  color: #fff;
}

:focus-visible {
  outline: 3px solid var(--cyan);
  outline-offset: 3px;
}

@media (max-width: 70rem) {
  .reader-layout {
    grid-template-columns: 16rem minmax(0, 1fr);
  }

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

@media (max-width: 52rem) {
  .reader-header {
    position: relative;
  }

  .reader-progress {
    width: min(12rem, 40vw);
  }

  .reader-layout {
    display: block;
  }

  .reader-sidebar {
    display: none;
  }

  .mobile-course-nav {
    display: block;
    margin: 1rem;
    padding: 0.8rem 1rem;
    background: var(--navy);
    border-radius: 0.8rem;
  }

  .mobile-course-nav summary {
    color: #fff;
    cursor: pointer;
    font-size: 0.82rem;
    font-weight: 750;
  }

  .mobile-course-nav .sidebar-label {
    margin-top: 1rem;
  }

  .mobile-course-nav .module-navigation {
    margin-top: 0.65rem;
  }

  .mobile-course-nav .mobile-lessons-label {
    padding-top: 1rem;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
  }

  .mobile-course-nav .lesson-navigation {
    margin-top: 0.8rem;
  }

  .lesson-hero {
    padding-top: 4rem;
  }
}

@media (max-width: 38rem) {
  .reader-brand small {
    display: none;
  }

  .reader-progress {
    width: 7rem;
  }

  .reader-progress > span {
    font-size: 0.62rem;
  }

  .lesson-hero {
    padding-right: 1.25rem;
    padding-left: 1.25rem;
  }

  .lesson-hero h1 {
    font-size: clamp(2.2rem, 13vw, 3.3rem);
  }

  .lesson-meta span {
    width: 100%;
  }

  .lesson-meta span + span::before {
    display: none;
  }

  .lesson-content {
    width: min(calc(100% - 2rem), var(--reading));
  }

  .lesson-content table {
    display: block;
    overflow-x: auto;
  }

  .pager {
    grid-template-columns: 1fr;
    width: min(calc(100% - 2rem), var(--reading));
  }

  .pager__empty {
    display: none;
  }

  .pager__link--next {
    text-align: left;
  }

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

@media print {
  .reader-header,
  .reader-sidebar,
  .mobile-course-nav,
  .pager,
  .lesson-footer,
  .source-link {
    display: none;
  }

  .reader-layout {
    display: block;
  }

  .lesson-hero {
    padding: 2rem 0;
    color: #000;
    background: transparent;
  }

  .lesson-kicker,
  .lesson-meta {
    color: #333;
  }

  .lesson-content {
    width: 100%;
    padding: 0;
  }

  .lesson-content pre {
    white-space: pre-wrap;
  }
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
}