/* Header */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: var(--paper);
  border-bottom: 1px solid var(--line);
}

.header-inner {
  display: flex;
  align-items: center;
  gap: 1.5rem;
  min-height: 64px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
  min-height: 44px;
  text-decoration: none;
  flex: none;
}

.brand-mark {
  display: grid;
  place-items: center;
  width: 28px;
  height: 28px;
  border-radius: 3px;
  background: var(--accent);
  color: var(--accent-ink);
}

.brand-word {
  font-family: var(--font-display);
  font-size: 1.18rem;
  font-weight: 600;
  letter-spacing: 0.01em;
}

.site-nav {
  display: flex;
  align-items: center;
  gap: 1.4rem;
  margin-left: auto;
}

.site-nav a {
  padding-block: 0.35rem;
  border-bottom: 1px solid transparent;
  color: var(--ink-soft);
  font-size: 0.92rem;
  text-decoration: none;
}

.site-nav a:hover {
  color: var(--ink);
  border-bottom-color: var(--line-strong);
}

.site-nav a[aria-current="page"] {
  color: var(--ink);
  border-bottom-color: var(--accent);
}

.site-nav .nav-cta {
  display: none;
  color: var(--accent-ink);
}

.site-nav .nav-cta:hover {
  color: var(--accent-ink);
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  margin-left: 1rem;
}

.header-stats {
  display: flex;
  gap: 0.8rem;
  margin-right: 0.35rem;
}

.header-stat {
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
  color: var(--ink-meta);
  font-family: var(--font-mono);
  font-size: 0.75rem;
}

.icon-button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  padding: 0;
  border: 1px solid var(--line);
  border-radius: 2px;
  background: transparent;
  color: var(--ink-soft);
  transition: background-color var(--motion-fast) ease, border-color var(--motion-fast) ease, color var(--motion-fast) ease;
}

.icon-button:hover {
  background: var(--paper-sunken);
  border-color: var(--line-strong);
  color: var(--ink);
}

.nav-toggle {
  display: none;
}

/* Buttons */
.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  min-height: 44px;
  padding: 0.65rem 1.05rem;
  border: 1px solid transparent;
  border-radius: 2px;
  font-size: 0.93rem;
  font-weight: 500;
  line-height: 1.2;
  text-align: center;
  text-decoration: none;
  transition: background-color var(--motion-fast) ease, border-color var(--motion-fast) ease, color var(--motion-fast) ease;
}

.button-primary {
  background: var(--accent);
  border-color: var(--accent);
  color: var(--accent-ink);
}

.button-primary:hover {
  background: var(--accent-strong);
  border-color: var(--accent-strong);
}

.button-secondary {
  background: transparent;
  border-color: var(--line-strong);
  color: var(--ink);
}

.button-secondary:hover {
  background: var(--paper-sunken);
  border-color: var(--ink-meta);
}

.button-quiet {
  min-height: 36px;
  padding: 0.35rem 0.35rem;
  background: transparent;
  color: var(--ink-soft);
}

.button-quiet:hover {
  color: var(--ink);
  text-decoration: underline;
}

.button-small {
  min-height: 36px;
  padding: 0.4rem 0.75rem;
  font-size: 0.82rem;
}

.button[disabled],
.button[aria-disabled="true"] {
  opacity: 0.5;
  cursor: not-allowed;
}

.button[disabled]:hover {
  background: var(--accent);
  border-color: var(--accent);
}

/* Status and progress */
.status {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  color: var(--ink-meta);
  font-family: var(--font-mono);
  font-size: 0.72rem;
  line-height: 1.4;
}

.status::before {
  content: "";
  width: 6px;
  height: 6px;
  background: currentColor;
  flex: none;
}

.status-open {
  color: var(--pass);
}

.status-progress {
  color: var(--warn);
}

.progress {
  height: 5px;
  overflow: hidden;
  border: 1px solid var(--line);
  background: var(--paper-sunken);
}

.progress-fill {
  display: block;
  height: 100%;
  background: var(--accent);
}

/* Hero */
.hero {
  padding-block: clamp(2.5rem, 6vw, 5.5rem) clamp(3rem, 7vw, 6rem);
}

.hero-grid {
  display: grid;
  grid-template-columns: repeat(12, minmax(0, 1fr));
  gap: clamp(1.5rem, 4vw, 4rem);
  align-items: center;
}

.hero-copy {
  grid-column: 1 / span 6;
}

.hero-demo {
  grid-column: 7 / span 6;
  min-width: 0;
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 0.55rem;
  margin-bottom: 1.5rem;
  color: var(--ink-meta);
  font-family: var(--font-mono);
  font-size: 0.74rem;
  line-height: 1.4;
}

.eyebrow::before {
  content: "";
  width: 8px;
  height: 8px;
  background: var(--accent);
  flex: none;
}

.hero h1 {
  max-width: 14ch;
}

.hero .lede {
  margin-top: 1.4rem;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-top: 2rem;
}

.hero-note {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  margin-top: 1.75rem;
  color: var(--ink-meta);
  font-size: 0.85rem;
}

.hero-note .icon {
  color: var(--accent);
}

.demo-panel {
  overflow: hidden;
  border: 1px solid var(--line-strong);
  border-radius: 4px;
  background: var(--paper-raised);
  box-shadow: 0 1px 2px rgba(31, 29, 26, 0.06), 0 18px 40px -24px rgba(31, 29, 26, 0.35);
}

.demo-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 1rem 1.1rem;
  border-bottom: 1px solid var(--line);
}

.demo-kicker {
  color: var(--accent);
  font-family: var(--font-mono);
  font-size: 0.68rem;
  line-height: 1.4;
}

.demo-title {
  margin-top: 0.2rem;
  font-family: var(--font-display);
  font-size: 1.05rem;
  line-height: 1.3;
}

.demo-body {
  display: grid;
  grid-template-columns: 1.15fr 0.85fr;
  min-height: 300px;
}

.demo-code {
  width: 100%;
  min-height: 300px;
  padding: 1rem;
  border: 0;
  border-right: 1px solid var(--line);
  border-radius: 0;
  background: var(--paper-sunken);
  color: var(--ink);
  font-family: var(--font-mono);
  font-size: 0.76rem;
  line-height: 1.65;
  tab-size: 2;
  resize: vertical;
}

.demo-preview {
  display: flex;
  min-width: 0;
  flex-direction: column;
  background: #ffffff;
}

.preview-label {
  padding: 0.5rem 0.8rem;
  border-bottom: 1px solid #e4ded2;
  color: #6b655b;
  font-family: var(--font-mono);
  font-size: 0.66rem;
  line-height: 1.4;
}

.demo-preview iframe {
  width: 100%;
  min-height: 260px;
  flex: 1;
  border: 0;
  background: #ffffff;
}

.demo-foot {
  display: flex;
  align-items: center;
  gap: 0.45rem;
  padding: 0.7rem 1.1rem;
  border-top: 1px solid var(--line);
  background: var(--paper);
  color: var(--ink-meta);
  font-size: 0.78rem;
}

.demo-foot .icon {
  color: var(--pass);
}

/* Method band */
.method {
  padding-block: clamp(3rem, 6vw, 4.5rem);
  border-block: 1px solid var(--line);
  background: var(--paper-sunken);
}

.method-grid {
  display: grid;
  grid-template-columns: 0.9fr 1.1fr;
  gap: clamp(2rem, 6vw, 5rem);
}

.method-intro h2 {
  max-width: 14ch;
  margin-top: 0.75rem;
}

.method-intro > p:last-child {
  max-width: 32rem;
  margin-top: 1rem;
  color: var(--ink-soft);
}

.method-list {
  padding: 0;
  border-top: 1px solid var(--line-strong);
  list-style: none;
}

.method-list li {
  display: grid;
  grid-template-columns: 3rem minmax(0, 1fr);
  gap: 1rem;
  padding: 1.1rem 0;
  border-bottom: 1px solid var(--line);
}

.method-num {
  padding-top: 0.25rem;
  color: var(--accent);
  font-family: var(--font-mono);
  font-size: 0.75rem;
}

.method-list h3 {
  font-size: 1.15rem;
}

.method-list p {
  margin-top: 0.3rem;
  color: var(--ink-soft);
  font-size: 0.93rem;
}

/* Section heads and course rows */
.section-head {
  display: flex;
  align-items: end;
  justify-content: space-between;
  gap: 2rem;
  margin-bottom: 2rem;
}

.section-head h2 {
  max-width: 16ch;
  margin-top: 0.65rem;
}

.section-head-note {
  max-width: 24rem;
  color: var(--ink-meta);
  font-size: 0.92rem;
}

.course-rows {
  padding: 0;
  border-top: 1px solid var(--line-strong);
  list-style: none;
}

.course-row {
  border-bottom: 1px solid var(--line);
}

.course-row-link {
  display: grid;
  grid-template-columns: 3rem minmax(0, 1.4fr) minmax(0, 0.9fr) 9rem 1.5rem;
  gap: 1rem;
  align-items: center;
  padding: 1.35rem 0.25rem;
  text-decoration: none;
  transition: background-color var(--motion-fast) ease;
}

.course-row-link:hover {
  background: var(--paper-raised);
}

.course-index {
  color: var(--ink-meta);
  font-family: var(--font-mono);
  font-size: 0.72rem;
}

.course-title {
  display: block;
  font-family: var(--font-display);
  font-size: 1.6rem;
  line-height: 1.25;
}

.course-sub {
  display: block;
  margin-top: 0.15rem;
  color: var(--ink-meta);
  font-size: 0.85rem;
}

.course-meta {
  color: var(--ink-meta);
  font-family: var(--font-mono);
  font-size: 0.72rem;
}

.course-arrow {
  color: var(--accent);
  opacity: 0.65;
  transition: opacity var(--motion-fast) ease, transform var(--motion-fast) ease;
}

.course-row-link:hover .course-arrow {
  opacity: 1;
  transform: translateX(2px);
}

/* Split facts */
.split-grid {
  display: grid;
  grid-template-columns: 0.9fr 1.1fr;
  gap: clamp(2rem, 6vw, 5rem);
}

.split-intro h2 {
  max-width: 15ch;
  margin-top: 0.75rem;
}

.split-intro > p:last-child {
  max-width: 32rem;
  margin-top: 1rem;
  color: var(--ink-soft);
}

.fact-list {
  margin: 0;
  border-top: 1px solid var(--line-strong);
}

.fact-list > div {
  display: grid;
  grid-template-columns: 11rem minmax(0, 1fr);
  gap: 1.5rem;
  padding: 1.1rem 0;
  border-bottom: 1px solid var(--line);
}

.fact-list dt {
  font-size: 0.93rem;
  font-weight: 600;
}

.fact-list dd {
  margin: 0;
  color: var(--ink-soft);
  font-size: 0.93rem;
}

/* Closing */
.closing {
  padding-block: clamp(3.5rem, 8vw, 7rem);
  border-top: 1px solid var(--line);
}

.closing-inner {
  display: grid;
  justify-items: start;
  gap: 1rem;
}

.closing-seal {
  display: grid;
  place-items: center;
  width: 56px;
  height: 56px;
  margin-bottom: 0.5rem;
  border-radius: 4px;
  background: var(--accent);
  color: var(--accent-ink);
}

.closing h2 {
  max-width: 18ch;
}

.closing p {
  color: var(--ink-soft);
}

.closing .button {
  margin-top: 0.75rem;
}

/* Footer */
.site-footer {
  padding-block: 2.5rem;
  border-top: 1px solid var(--line);
  background: var(--paper);
}

.footer-inner {
  display: grid;
  grid-template-columns: 1.4fr 0.6fr 1fr;
  gap: 2rem;
  align-items: start;
}

.footer-brand p {
  max-width: 22rem;
  margin-top: 0.7rem;
  color: var(--ink-meta);
  font-size: 0.88rem;
}

.footer-nav {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.footer-nav a {
  color: var(--ink-soft);
  font-size: 0.9rem;
  text-decoration: none;
}

.footer-nav a:hover {
  color: var(--ink);
  text-decoration: underline;
}

.footer-note {
  color: var(--ink-meta);
  font-size: 0.8rem;
}

.footer-note a {
  color: inherit;
}

/* Page heads */
.page-head {
  padding-block: clamp(2.5rem, 6vw, 4.5rem) clamp(2rem, 4vw, 3rem);
}

.page-head h1 {
  margin-top: 0.7rem;
}

.page-head .lede {
  margin-top: 1rem;
}

.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  color: var(--ink-meta);
  font-family: var(--font-mono);
  font-size: 0.72rem;
  line-height: 1.5;
}

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

.breadcrumb a:hover {
  color: var(--ink);
  text-decoration: underline;
}

.breadcrumb .sep {
  color: var(--ink-meta);
}

/* Catalog page */
.catalog-list {
  border-top: 1px solid var(--line-strong);
}

.catalog-item {
  display: grid;
  grid-template-columns: 3rem minmax(0, 1fr) 16rem;
  gap: clamp(1rem, 3vw, 2.5rem);
  padding: clamp(1.5rem, 3vw, 2.25rem) 0;
  border-bottom: 1px solid var(--line);
}

.catalog-index {
  color: var(--accent);
  font-family: var(--font-mono);
  font-size: 0.75rem;
  line-height: 1.6;
}

.catalog-title-row {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 0.75rem 1rem;
}

.catalog-title {
  font-family: var(--font-display);
  font-size: 1.8rem;
  line-height: 1.2;
  padding-block: 0.45rem;
  margin-block: -0.45rem;
  text-decoration: none;
}

.catalog-title:hover {
  text-decoration: underline;
  text-decoration-thickness: 1px;
}

.catalog-sub {
  color: var(--ink-meta);
  font-size: 0.9rem;
}

.catalog-item > div > p {
  max-width: 38rem;
  margin-top: 0.5rem;
  color: var(--ink-soft);
  font-size: 0.95rem;
}

.catalog-side {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 0.75rem;
}

.catalog-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  color: var(--ink-meta);
  font-family: var(--font-mono);
  font-size: 0.7rem;
}

.catalog-progress {
  display: grid;
  width: 100%;
  gap: 0.35rem;
}

.catalog-progress-label {
  color: var(--ink-meta);
  font-family: var(--font-mono);
  font-size: 0.68rem;
}

.catalog-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-top: 0.9rem;
}

.planned {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
  margin-top: 0.75rem;
  padding: 0;
  list-style: none;
}

.planned li {
  padding: 0.2rem 0.45rem;
  border: 1px solid var(--line);
  border-radius: 2px;
  color: var(--ink-meta);
  font-family: var(--font-mono);
  font-size: 0.68rem;
  line-height: 1.5;
}

/* Course page */
.course-hero {
  padding-block: clamp(2rem, 5vw, 4rem) clamp(2.5rem, 5vw, 4rem);
  border-bottom: 1px solid var(--line);
}

.course-hero-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 18rem;
  gap: clamp(2rem, 5vw, 4rem);
  align-items: end;
}

.course-hero .course-title {
  margin-top: 0.8rem;
  font-size: clamp(3rem, 2rem + 5vw, 5.5rem);
  line-height: 1;
}

.course-hero .course-sub {
  margin-top: 0.6rem;
  color: var(--ink-soft);
  font-size: 1.1rem;
}

.course-description {
  max-width: 38rem;
  margin-top: 1rem;
  color: var(--ink-soft);
}

.course-meta-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem 1.25rem;
  margin-top: 1.5rem;
  color: var(--ink-meta);
  font-family: var(--font-mono);
  font-size: 0.72rem;
}

.course-meta-row span {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
}

.course-side {
  display: grid;
  gap: 1rem;
  padding-top: 1.1rem;
  border-top: 1px solid var(--line-strong);
}

.course-side .button {
  width: 100%;
}

.course-side-progress {
  display: grid;
  gap: 0.4rem;
}

.course-side-label {
  display: flex;
  justify-content: space-between;
  gap: 0.75rem;
  color: var(--ink-meta);
  font-family: var(--font-mono);
  font-size: 0.7rem;
}

.course-note {
  max-width: 46rem;
  margin-top: 1.5rem;
  padding: 0.9rem 1rem;
  border: 1px solid var(--line);
  background: var(--paper-sunken);
  color: var(--ink-soft);
  font-size: 0.92rem;
}

.module {
  padding-block: clamp(2rem, 4vw, 3rem);
  border-bottom: 1px solid var(--line);
}

.module-head {
  display: flex;
  align-items: end;
  justify-content: space-between;
  gap: 2rem;
  margin-bottom: 1.5rem;
}

.module-kicker {
  color: var(--accent);
  font-family: var(--font-mono);
  font-size: 0.72rem;
}

.module h2 {
  margin-top: 0.35rem;
  font-size: 1.7rem;
}

.module-desc {
  max-width: 36rem;
  margin-top: 0.5rem;
  color: var(--ink-soft);
  font-size: 0.95rem;
}

.lesson-rows {
  padding: 0;
  border-top: 1px solid var(--line);
  list-style: none;
}

.lesson-row a {
  display: grid;
  grid-template-columns: 2.5rem minmax(0, 1fr) auto auto;
  gap: 1rem;
  align-items: center;
  padding: 1rem 0.25rem;
  border-bottom: 1px solid var(--line);
  text-decoration: none;
  transition: background-color var(--motion-fast) ease;
}

.lesson-row a:hover {
  background: var(--paper-raised);
}

.lesson-num {
  color: var(--ink-meta);
  font-family: var(--font-mono);
  font-size: 0.72rem;
}

.lesson-title {
  font-weight: 500;
}

.lesson-meta {
  color: var(--ink-meta);
  font-family: var(--font-mono);
  font-size: 0.7rem;
}

.lesson-state {
  color: var(--pass);
}

.planned-block {
  max-width: 46rem;
  padding-block: 3rem;
}

.planned-block h2 {
  margin-top: 0.5rem;
  font-size: 1.7rem;
}

.planned-block > p {
  margin-top: 0.75rem;
  color: var(--ink-soft);
}

.planned-block .planned {
  margin-top: 1.25rem;
}

/* Lesson layout */
.lesson-layout {
  display: grid;
  grid-template-columns: 17rem minmax(0, 1fr);
  gap: clamp(2rem, 5vw, 4.5rem);
  align-items: start;
  padding-block: 2rem 5rem;
}

.lesson-sidebar {
  position: sticky;
  top: 88px;
  max-height: calc(100vh - 112px);
  overflow: auto;
  padding-top: 1rem;
  border-top: 1px solid var(--line-strong);
}

.sidebar-course {
  font-family: var(--font-display);
  font-size: 1.1rem;
  line-height: 1.3;
}

.sidebar-module {
  margin-top: 0.35rem;
  color: var(--ink-meta);
  font-family: var(--font-mono);
  font-size: 0.68rem;
}

.sidebar-progress {
  display: grid;
  gap: 0.4rem;
  margin-top: 1rem;
}

.sidebar-progress-label {
  display: flex;
  justify-content: space-between;
  gap: 0.75rem;
  color: var(--ink-meta);
  font-family: var(--font-mono);
  font-size: 0.68rem;
}

.sidebar-toggle {
  display: none;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  width: 100%;
  margin-top: 1.25rem;
  padding: 0.7rem 0;
  border: 0;
  border-top: 1px solid var(--line-strong);
  background: transparent;
  color: var(--ink);
  font-family: var(--font-mono);
  font-size: 0.72rem;
  text-align: left;
}

.sidebar-toggle-meta {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  color: var(--ink-meta);
}

.sidebar-toggle .icon {
  transition: transform var(--motion-fast) ease;
}

.sidebar-toggle[aria-expanded="true"] .icon {
  transform: rotate(180deg);
}

.sidebar-list {
  margin-top: 1.25rem;
  padding: 0;
  list-style: none;
}

.sidebar-list a {
  display: grid;
  grid-template-columns: 1.5rem minmax(0, 1fr) auto;
  gap: 0.5rem;
  align-items: start;
  padding: 0.55rem 0;
  border-top: 1px solid var(--line);
  color: var(--ink-soft);
  font-size: 0.86rem;
  line-height: 1.45;
  text-decoration: none;
}

.sidebar-list a:hover {
  color: var(--ink);
}

.sidebar-list a[aria-current="page"] {
  color: var(--ink);
  font-weight: 500;
}

.sidebar-num {
  color: var(--ink-meta);
  font-family: var(--font-mono);
  font-size: 0.68rem;
  padding-top: 0.1rem;
}

.sidebar-check {
  color: var(--pass);
  padding-top: 0.1rem;
}

.lesson-main {
  min-width: 0;
  max-width: 760px;
}

.lesson-head {
  padding-bottom: 2rem;
  border-bottom: 1px solid var(--line);
}

.lesson-head h1 {
  margin-top: 0.6rem;
  font-size: clamp(2.1rem, 1.5rem + 2.4vw, 3.3rem);
}

.lesson-meta-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem 1.1rem;
  margin-top: 1rem;
  color: var(--ink-meta);
  font-family: var(--font-mono);
  font-size: 0.72rem;
}

.lesson-meta-row span {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
}

.goal {
  display: grid;
  gap: 0.35rem;
  margin-top: 1.75rem;
  padding: 1rem 1.1rem;
  border: 1px solid var(--line);
  border-radius: 2px;
  background: var(--paper-raised);
}

.goal-label {
  color: var(--accent);
  font-family: var(--font-mono);
  font-size: 0.68rem;
}

.goal p {
  font-size: 0.95rem;
}

/* Theory */
.theory {
  display: grid;
  gap: 1.25rem;
  padding-block: 2rem;
}

.theory h3 {
  margin-top: 0.75rem;
}

.theory p,
.theory li {
  color: var(--ink-soft);
}

.theory ul {
  display: grid;
  gap: 0.35rem;
  padding-left: 1.2rem;
}

.code-block {
  overflow: hidden;
  border: 1px solid var(--line-strong);
  border-radius: 2px;
  background: var(--paper-raised);
}

.code-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 0.4rem 0.65rem;
  border-bottom: 1px solid var(--line);
  background: var(--paper-sunken);
}

.code-lang {
  color: var(--ink-meta);
  font-family: var(--font-mono);
  font-size: 0.68rem;
}

.copy-code {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  padding: 0.25rem 0.4rem;
  border: 0;
  border-radius: 2px;
  background: transparent;
  color: var(--ink-meta);
  font-family: var(--font-mono);
  font-size: 0.68rem;
}

.copy-code:hover {
  background: var(--paper);
  color: var(--ink);
}

.code-block pre {
  margin: 0;
  padding: 0.9rem 1rem;
  overflow: auto;
  color: var(--ink);
  font-family: var(--font-mono);
  font-size: 0.82rem;
  line-height: 1.7;
  tab-size: 2;
}

.code-block code {
  font-family: inherit;
}

.note {
  display: grid;
  gap: 0.35rem;
  padding: 0.9rem 1rem;
  border: 1px solid var(--line);
  border-radius: 2px;
  background: var(--paper-sunken);
}

.note-label {
  color: var(--ink-meta);
  font-family: var(--font-mono);
  font-size: 0.68rem;
}

.note p {
  color: var(--ink-soft);
  font-size: 0.9rem;
}

/* Quiz */
.exercise {
  padding-block: 2.5rem;
  border-top: 1px solid var(--line);
}

.exercise-head {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 1rem;
}

.exercise h2 {
  font-size: 1.6rem;
}

.exercise-kicker {
  color: var(--accent);
  font-family: var(--font-mono);
  font-size: 0.68rem;
}

.quiz-question {
  margin-top: 1rem;
  font-weight: 500;
}

.quiz-options {
  display: grid;
  gap: 0.5rem;
  margin-top: 1rem;
  padding: 0;
  border: 0;
  list-style: none;
}

.quiz-option {
  display: flex;
  align-items: flex-start;
  gap: 0.65rem;
  padding: 0.75rem 0.85rem;
  border: 1px solid var(--line);
  border-radius: 2px;
  background: var(--paper-raised);
  cursor: pointer;
  font-size: 0.93rem;
  transition: border-color var(--motion-fast) ease, background-color var(--motion-fast) ease;
}

.quiz-option:hover {
  border-color: var(--line-strong);
}

.quiz-option:has(input:checked) {
  border-color: var(--accent);
}

.quiz-option.is-correct {
  border-color: var(--pass);
}

.quiz-option.is-wrong {
  border-color: var(--accent);
}

.quiz-option input {
  margin-top: 0.3rem;
  accent-color: var(--accent);
}

.quiz-option code {
  font-family: var(--font-mono);
  font-size: 0.88em;
}

.quiz-actions {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.75rem;
  margin-top: 1rem;
}

.feedback {
  display: flex;
  align-items: flex-start;
  gap: 0.5rem;
  margin-top: 0.9rem;
  font-size: 0.9rem;
}

.feedback.is-pass {
  color: var(--pass);
}

.feedback.is-fail {
  color: var(--accent);
}

.feedback .icon {
  margin-top: 0.15rem;
}

/* Challenge */
.challenge-prompt {
  margin-top: 1rem;
  color: var(--ink-soft);
}

.requirements {
  display: grid;
  gap: 0.35rem;
  margin-top: 1rem;
  padding-left: 1.2rem;
  color: var(--ink-soft);
  font-size: 0.92rem;
}

.editor {
  margin-top: 1.5rem;
  overflow: hidden;
  border: 1px solid var(--line-strong);
  border-radius: 4px;
  background: var(--paper-raised);
}

.editor-bar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
  padding: 0.5rem 0.6rem 0.5rem 0.8rem;
  border-bottom: 1px solid var(--line);
  background: var(--paper-sunken);
}

.editor-file {
  color: var(--ink-meta);
  font-family: var(--font-mono);
  font-size: 0.72rem;
}

.editor-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
}

.editor-grid {
  display: grid;
  grid-template-columns: 1.1fr 0.9fr;
  min-height: 320px;
}

.editor-code {
  width: 100%;
  min-height: 320px;
  padding: 1rem;
  border: 0;
  border-right: 1px solid var(--line);
  border-radius: 0;
  background: var(--paper-raised);
  color: var(--ink);
  font-family: var(--font-mono);
  font-size: 0.8rem;
  line-height: 1.65;
  tab-size: 2;
  resize: vertical;
}

.editor-preview {
  display: flex;
  min-width: 0;
  flex-direction: column;
  background: #ffffff;
}

.editor-preview .preview-label {
  border-bottom-color: #e4ded2;
}

.editor-preview iframe {
  width: 100%;
  min-height: 280px;
  flex: 1;
  border: 0;
  background: #ffffff;
}

.editor-error {
  display: block;
  margin: 0;
  padding: 0.85rem 1rem;
  border-top: 1px solid var(--line-strong);
  color: var(--accent);
  font-family: var(--font-mono);
  font-size: 0.78rem;
  line-height: 1.5;
}

.checks {
  margin-top: 1rem;
  border-top: 1px solid var(--line);
}

.checks ul {
  margin: 0;
  padding: 0;
  list-style: none;
}

.checks-head {
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  padding: 0.6rem 0;
  color: var(--ink-meta);
  font-family: var(--font-mono);
  font-size: 0.7rem;
}

.check-item {
  display: grid;
  grid-template-columns: 1.25rem minmax(0, 1fr) auto;
  gap: 0.55rem;
  align-items: start;
  padding: 0.55rem 0;
  border-top: 1px solid var(--line);
  font-size: 0.88rem;
}

.check-icon {
  display: flex;
  padding-top: 0.1rem;
  color: var(--ink-meta);
}

.check-item.is-pass .check-icon {
  color: var(--pass);
}

.check-item.is-fail .check-icon {
  color: var(--accent);
}

.check-pending {
  display: block;
  width: 10px;
  height: 10px;
  margin-top: 0.25rem;
  border: 1px solid var(--line-strong);
}

.check-state {
  color: var(--ink-meta);
  font-family: var(--font-mono);
  font-size: 0.68rem;
}

.check-item.is-pass .check-state {
  color: var(--pass);
}

.check-item.is-fail .check-state {
  color: var(--accent);
}

.hint {
  margin-top: 1rem;
  padding: 0.8rem 0.9rem;
  border: 1px solid var(--line);
  border-radius: 2px;
  background: var(--paper-sunken);
  color: var(--ink-soft);
  font-size: 0.9rem;
}

.solution {
  margin-top: 1rem;
}

.solution-note {
  margin-bottom: 0.6rem;
  color: var(--ink-meta);
  font-size: 0.85rem;
}

.finish-panel {
  display: grid;
  gap: 1rem;
  margin-top: 2.5rem;
  padding: 1.25rem;
  border: 1px solid var(--line-strong);
  border-radius: 2px;
  background: var(--paper-raised);
}

.finish-panel.is-complete {
  border-color: var(--pass);
}

.finish-title {
  font-family: var(--font-display);
  font-size: 1.3rem;
  line-height: 1.3;
}

.finish-title .icon {
  color: var(--pass);
  vertical-align: -0.15em;
}

.finish-status {
  display: flex;
  flex-wrap: wrap;
  gap: 0.6rem 1.25rem;
  color: var(--ink-meta);
  font-family: var(--font-mono);
  font-size: 0.72rem;
}

.finish-status span {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
}

.finish-status .is-done {
  color: var(--pass);
}

.finish-actions {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.75rem;
}

.finish-hint {
  color: var(--ink-meta);
  font-size: 0.82rem;
}

.lesson-nav {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 1rem;
  margin-top: 2rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--line);
}

.lesson-nav a {
  display: grid;
  gap: 0.2rem;
  max-width: 18rem;
  font-size: 0.9rem;
  text-decoration: none;
}

.lesson-nav a:hover {
  text-decoration: underline;
}

.lesson-nav-label {
  color: var(--ink-meta);
  font-family: var(--font-mono);
  font-size: 0.68rem;
}

.lesson-nav-next {
  margin-left: auto;
  text-align: right;
  justify-items: end;
}

/* Progress page */
.stats-strip {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  border-block: 1px solid var(--line-strong);
}

.stat {
  padding: 1.25rem 1.25rem 1.25rem 0;
  border-right: 1px solid var(--line);
}

.stat:last-child {
  border-right: 0;
}

.stat-label {
  color: var(--ink-meta);
  font-family: var(--font-mono);
  font-size: 0.7rem;
}

.stat-value {
  margin-top: 0.35rem;
  font-family: var(--font-display);
  font-size: 2.2rem;
  line-height: 1.1;
}

.stat-note {
  margin-top: 0.2rem;
  color: var(--ink-meta);
  font-size: 0.8rem;
}

.progress-section {
  padding-block: clamp(2rem, 4vw, 3rem);
}

.progress-section h2 {
  font-size: 1.6rem;
}

.progress-course {
  display: grid;
  grid-template-columns: 8rem minmax(0, 1fr) 8rem;
  gap: 1.5rem;
  align-items: center;
  padding: 1.1rem 0;
  border-bottom: 1px solid var(--line);
}

.progress-course:first-of-type {
  margin-top: 1rem;
  border-top: 1px solid var(--line-strong);
}

.progress-course-name {
  font-family: var(--font-display);
  font-size: 1.2rem;
  line-height: 1.3;
}

.progress-course .progress {
  width: 100%;
}

.progress-course-meta {
  color: var(--ink-meta);
  font-family: var(--font-mono);
  font-size: 0.7rem;
  text-align: right;
}

.section-heading {
  display: flex;
  flex-wrap: wrap;
  align-items: flex-end;
  justify-content: space-between;
  gap: 1rem;
  margin-bottom: 1rem;
}

.section-note {
  max-width: 34rem;
  color: var(--ink-meta);
  font-size: 0.85rem;
  line-height: 1.55;
}

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

.reward-card {
  display: grid;
  align-content: start;
  gap: 0.6rem;
  padding: 1.25rem;
  border: 1px solid var(--line-strong);
  border-radius: 2px;
  background: var(--paper-raised);
}

.reward-card-head {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.reward-icon {
  display: inline-flex;
  color: var(--accent);
}

.reward-kicker {
  color: var(--ink-meta);
  font-family: var(--font-mono);
  font-size: 0.7rem;
}

.reward-value {
  font-family: var(--font-display);
  font-size: 2rem;
  line-height: 1.15;
}

.reward-line {
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  padding-top: 0.55rem;
  border-top: 1px solid var(--line);
  font-size: 0.85rem;
}

.reward-line span {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
}

.reward-card .button {
  justify-self: start;
}

.reward-note {
  color: var(--ink-meta);
  font-size: 0.8rem;
  line-height: 1.5;
}

.mission-list {
  margin: 1rem 0 0;
  padding: 0;
  border-top: 1px solid var(--line-strong);
  list-style: none;
}

.mission-item {
  display: grid;
  grid-template-columns: 1.75rem minmax(0, 1fr) 10rem auto;
  gap: 1rem;
  align-items: center;
  padding: 1rem 0;
  border-bottom: 1px solid var(--line);
}

.mission-icon {
  display: inline-flex;
  color: var(--ink-meta);
}

.mission-item.is-complete .mission-icon,
.mission-item.is-claimed .mission-icon {
  color: var(--pass);
}

.mission-title {
  font-size: 0.95rem;
}

.mission-desc {
  margin-top: 0.15rem;
  color: var(--ink-meta);
  font-size: 0.82rem;
  line-height: 1.5;
}

.mission-meter {
  display: grid;
  gap: 0.35rem;
}

.mission-count {
  color: var(--ink-meta);
  font-family: var(--font-mono);
  font-size: 0.68rem;
  text-align: right;
}

.mission-claimed {
  color: var(--pass);
  font-family: var(--font-mono);
  font-size: 0.7rem;
}

.certificate-list {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 0.75rem;
  margin-top: 1rem;
}

.certificate-card {
  display: grid;
  grid-template-columns: 1.75rem minmax(0, 1fr);
  gap: 0.6rem 0.8rem;
  align-content: start;
  padding: 1rem;
  border: 1px solid var(--line);
  background: var(--paper-raised);
}

.certificate-card-icon {
  display: inline-flex;
  color: var(--ink-meta);
}

.certificate-card.is-ready .certificate-card-icon {
  color: var(--accent);
}

.certificate-card h3 {
  font-size: 1.1rem;
}

.certificate-card p {
  margin-top: 0.2rem;
  color: var(--ink-meta);
  font-size: 0.8rem;
}

.certificate-card .button,
.certificate-locked-label {
  grid-column: 2;
  justify-self: start;
}

.certificate-locked-label {
  color: var(--ink-meta);
  font-family: var(--font-mono);
  font-size: 0.7rem;
}

.history-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 0.75rem;
  margin-top: 1rem;
  padding: 0;
  list-style: none;
}

.history-card {
  display: grid;
  gap: 0.55rem;
  padding: 1rem;
  border: 1px solid var(--line);
  background: var(--paper-raised);
}

.history-card-top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
}

.history-icon {
  display: inline-flex;
  color: var(--pass);
}

.history-card-reward .history-icon {
  color: var(--accent);
}

.history-course {
  color: var(--ink-meta);
  font-family: var(--font-mono);
  font-size: 0.68rem;
}

.history-card-title {
  font-size: 0.95rem;
  line-height: 1.4;
}

.history-card-foot {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 0.5rem;
}

.history-xp {
  color: var(--pass);
  font-family: var(--font-mono);
  font-size: 0.72rem;
}

.history-spend {
  color: var(--warn);
  font-family: var(--font-mono);
  font-size: 0.7rem;
}

.history-date {
  color: var(--ink-meta);
  font-family: var(--font-mono);
  font-size: 0.7rem;
  text-align: right;
}

.empty {
  display: grid;
  justify-items: start;
  gap: 0.75rem;
  padding: 2rem;
  border: 1px dashed var(--line-strong);
}

.empty h2 {
  font-size: 1.5rem;
}

.empty p {
  max-width: 34rem;
  color: var(--ink-soft);
}

.data-note {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  margin-top: 2.5rem;
  padding: 1rem 1.1rem;
  border: 1px solid var(--line);
}

.data-note p {
  max-width: 38rem;
  color: var(--ink-meta);
  font-size: 0.86rem;
}

/* Certificate page */
.certificate-wrap {
  padding-bottom: 3rem;
}

.certificate-actions {
  display: grid;
  gap: 0.5rem;
  max-width: 32rem;
  margin-bottom: 1.5rem;
}

.certificate-actions label {
  color: var(--ink-meta);
  font-family: var(--font-mono);
  font-size: 0.72rem;
}

.certificate-actions input {
  min-height: 44px;
  padding: 0.65rem 0.8rem;
  border: 1px solid var(--line-strong);
  border-radius: 2px;
  background: var(--paper-raised);
  color: var(--ink);
  font: inherit;
}

.certificate-actions .button {
  justify-self: start;
}

.certificate-hint {
  color: var(--ink-meta);
  font-size: 0.8rem;
}

.certificate {
  display: grid;
  justify-items: center;
  gap: 1rem;
  max-width: 52rem;
  margin-inline: auto;
  padding: clamp(2rem, 6vw, 4.5rem);
  border: 1px solid var(--line-strong);
  background: var(--paper-raised);
  text-align: center;
}

.certificate-mark {
  display: grid;
  place-items: center;
  width: 56px;
  height: 56px;
  background: var(--accent);
  color: var(--accent-ink);
}

.certificate-kicker {
  color: var(--ink-meta);
  font-family: var(--font-mono);
  font-size: 0.72rem;
}

.certificate-course {
  font-family: var(--font-display);
  font-size: clamp(2.2rem, 5vw, 4rem);
  line-height: 1.1;
}

.certificate-for {
  color: var(--ink-meta);
  font-size: 0.85rem;
}

.certificate-name {
  min-width: 16rem;
  max-width: 100%;
  padding-bottom: 0.5rem;
  border-bottom: 1px solid var(--line-strong);
  font-family: var(--font-display);
  font-size: clamp(1.6rem, 3vw, 2.4rem);
  line-height: 1.3;
  overflow-wrap: anywhere;
}

.certificate-name.is-placeholder {
  color: var(--ink-meta);
}

.certificate-copy {
  max-width: 32rem;
  color: var(--ink-soft);
}

.certificate-meta {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 1.5rem;
  margin-top: 0.5rem;
}

.certificate-meta div {
  display: grid;
  gap: 0.15rem;
}

.certificate-meta dt {
  color: var(--ink-meta);
  font-family: var(--font-mono);
  font-size: 0.68rem;
}

.certificate-meta dd {
  margin: 0;
  font-size: 0.9rem;
}

.certificate-note {
  max-width: 30rem;
  color: var(--ink-meta);
  font-size: 0.75rem;
  line-height: 1.5;
}

.certificate-locked {
  display: grid;
  gap: 1rem;
  max-width: 40rem;
  margin-top: 1rem;
  padding: 2rem;
  border: 1px solid var(--line-strong);
  background: var(--paper-raised);
}

.certificate-locked h2 {
  font-size: 1.6rem;
}

.certificate-locked p {
  color: var(--ink-soft);
}

/* Projects and extra practice */
.project-list {
  border-top: 1px solid var(--line-strong);
}

.project-row {
  display: grid;
  grid-template-columns: 2.5rem minmax(0, 1fr) 12rem;
  gap: 1.25rem;
  align-items: start;
  padding: 1.5rem 0;
  border-bottom: 1px solid var(--line);
}

.project-index {
  padding-top: 0.35rem;
  color: var(--ink-meta);
  font-family: var(--font-mono);
  font-size: 0.72rem;
}

.project-body {
  display: grid;
  gap: 0.45rem;
  min-width: 0;
}

.project-title-row {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 0.5rem 0.9rem;
}

.project-title {
  font-family: var(--font-display);
  font-size: 1.45rem;
  line-height: 1.2;
  text-decoration: none;
}

.project-title:hover {
  text-decoration: underline;
}

.project-language {
  color: var(--ink-meta);
  font-family: var(--font-mono);
  font-size: 0.68rem;
}

.project-body > p {
  max-width: 40rem;
  color: var(--ink-soft);
  font-size: 0.92rem;
}

.project-meta,
.challenge-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 0.35rem 1rem;
  color: var(--ink-meta);
  font-family: var(--font-mono);
  font-size: 0.68rem;
}

.project-meta span,
.challenge-meta span {
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
}

.project-side {
  display: grid;
  gap: 0.65rem;
  justify-items: start;
}

.project-side-progress {
  display: grid;
  gap: 0.4rem;
  width: 100%;
  color: var(--ink-meta);
  font-family: var(--font-mono);
  font-size: 0.68rem;
}

.project-footnote {
  max-width: 46rem;
  margin-top: 1.5rem;
  color: var(--ink-meta);
  font-size: 0.82rem;
}

.status-complete {
  color: var(--pass);
}

.project-steps {
  display: grid;
  gap: 1rem;
  margin-top: 0.75rem;
  padding-left: 0;
  list-style: none;
}

.project-steps li {
  display: grid;
  gap: 0.2rem;
  position: relative;
  padding-left: 2.2rem;
}

.project-steps li::before {
  content: counter(list-item, decimal-leading-zero);
  position: absolute;
  top: 0.15rem;
  left: 0;
  color: var(--accent);
  font-family: var(--font-mono);
  font-size: 0.68rem;
}

.project-step-title {
  color: var(--ink);
  font-weight: 500;
}

.project-related {
  margin-top: 0.25rem;
  color: var(--ink-meta);
  font-size: 0.85rem;
}

.checklist {
  display: grid;
  gap: 0.5rem;
  margin-top: 1rem;
  padding: 0;
  border: 0;
}

.checklist-item {
  display: flex;
  align-items: flex-start;
  gap: 0.7rem;
  min-height: 44px;
  padding: 0.75rem 0.85rem;
  border: 1px solid var(--line);
  border-radius: 2px;
  background: var(--paper-raised);
  cursor: pointer;
  font-size: 0.92rem;
}

.checklist-item:hover {
  border-color: var(--line-strong);
}

.checklist-item input {
  margin-top: 0.3rem;
  accent-color: var(--accent);
}

.checklist:disabled .checklist-item {
  cursor: default;
  opacity: 0.75;
}

.practice-summary {
  display: grid;
  grid-template-columns: 13rem minmax(0, 1fr);
  gap: 1.5rem;
  align-items: center;
  padding-block: 1.5rem;
  border-top: 1px solid var(--line-strong);
  border-bottom: 1px solid var(--line);
}

.practice-summary-value {
  font-family: var(--font-display);
  font-size: 2.4rem;
  line-height: 1;
}

.practice-summary-label {
  margin-top: 0.35rem;
  color: var(--ink-meta);
  font-family: var(--font-mono);
  font-size: 0.7rem;
}

.practice-summary-note {
  max-width: 42rem;
  color: var(--ink-soft);
  font-size: 0.92rem;
}

.challenge-group {
  margin-top: 2.5rem;
  padding-top: 2.5rem;
  border-top: 1px solid var(--line);
}

.challenge-group-head {
  display: flex;
  align-items: flex-end;
  justify-content: space-between;
  gap: 1rem;
  margin-bottom: 1rem;
}

.challenge-group-head h2 {
  font-size: 1.8rem;
}

.challenge-group-head p {
  margin-top: 0.35rem;
  color: var(--ink-meta);
  font-size: 0.88rem;
}

.challenge-group-count {
  color: var(--ink-meta);
  font-family: var(--font-mono);
  font-size: 0.7rem;
}

.challenge-list {
  padding: 0;
  border-top: 1px solid var(--line);
  list-style: none;
}

.challenge-row {
  display: grid;
  grid-template-columns: 2.4rem minmax(0, 1fr) 10rem;
  gap: 1rem;
  align-items: start;
  min-height: 44px;
  padding: 1.1rem 0.25rem;
  border-bottom: 1px solid var(--line);
  text-decoration: none;
  transition: background-color var(--motion-fast) ease;
}

.challenge-row:hover {
  background: var(--paper-raised);
}

.challenge-index {
  padding-top: 0.2rem;
  color: var(--ink-meta);
  font-family: var(--font-mono);
  font-size: 0.7rem;
}

.challenge-body,
.challenge-title-row {
  display: grid;
  gap: 0.3rem;
  min-width: 0;
}

.challenge-title-row {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 0.35rem 0.75rem;
}

.challenge-title {
  color: var(--ink);
  font-weight: 500;
}

.challenge-language {
  color: var(--ink-meta);
  font-family: var(--font-mono);
  font-size: 0.66rem;
}

.challenge-summary {
  color: var(--ink-soft);
  font-size: 0.88rem;
  line-height: 1.5;
}

.challenge-side {
  display: grid;
  gap: 0.35rem;
  justify-items: end;
  text-align: right;
}

.challenge-action {
  color: var(--accent);
  font-family: var(--font-mono);
  font-size: 0.68rem;
}

.history-card-title a {
  color: inherit;
  text-decoration: none;
}

.history-card-title a:hover {
  text-decoration: underline;
}

@media (max-width: 860px) {
  .practice-summary {
    grid-template-columns: 1fr;
    gap: 0.5rem;
  }

  .project-row,
  .challenge-row {
    grid-template-columns: 2rem minmax(0, 1fr);
    gap: 0.75rem 1rem;
  }

  .project-side,
  .challenge-side {
    grid-column: 2;
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    justify-content: flex-start;
    gap: 0.5rem 1rem;
    text-align: left;
  }

  .project-side-progress {
    max-width: 18rem;
  }

  .project-title,
  .challenge-row {
    min-height: 44px;
  }
}

@media (max-width: 600px) {
  .challenge-group-head {
    display: grid;
    gap: 0.35rem;
    align-items: start;
  }

  .project-title {
    font-size: 1.3rem;
  }
}

/* Toast */
.toast {
  position: fixed;
  left: 50%;
  bottom: 1.25rem;
  z-index: 80;
  max-width: calc(100vw - 2rem);
  padding: 0.7rem 1rem;
  border-radius: 2px;
  background: var(--ink);
  color: var(--paper);
  font-size: 0.88rem;
  opacity: 0;
  pointer-events: none;
  transform: translate(-50%, 1rem);
  transition: opacity var(--motion-slow) ease, transform var(--motion-slow) ease;
}

.toast.is-visible {
  opacity: 1;
  transform: translate(-50%, 0);
}

/* 404 */
.not-found {
  display: grid;
  place-items: center;
  min-height: 60vh;
  padding-block: 4rem;
}

.not-found-inner {
  display: grid;
  gap: 1rem;
  max-width: 32rem;
}

.not-found-code {
  color: var(--accent);
  font-family: var(--font-mono);
  font-size: 0.8rem;
}

/* Responsive */
@media (max-width: 1080px) {
  .header-stats {
    display: none;
  }
}

@media (max-width: 980px) {
  .hero-copy,
  .hero-demo {
    grid-column: 1 / -1;
  }

  .hero-copy {
    max-width: 42rem;
  }

  .hero-demo {
    max-width: 640px;
  }

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

  .method-intro h2,
  .split-intro h2 {
    max-width: 20ch;
  }

  .course-hero-grid {
    grid-template-columns: 1fr;
  }

  .course-side {
    max-width: 22rem;
  }

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

  .lesson-sidebar {
    position: static;
    max-height: none;
    order: -1;
  }

  .lesson-main {
    max-width: none;
  }

  .sidebar-toggle {
    display: flex;
    min-height: 44px;
  }

  .sidebar-lessons {
    display: none;
  }

  .sidebar-lessons[data-open="true"] {
    display: block;
  }

  .sidebar-list {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 0 1.5rem;
  }

  .sidebar-list li:nth-child(-n + 2) a {
    border-top: 1px solid var(--line);
  }
}

@media (max-width: 720px) {
  .module-head {
    display: block;
  }

  .module-head .muted {
    margin-top: 0.5rem;
  }
}

@media (max-width: 860px) {
  .site-nav {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    display: none;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    margin-left: 0;
    padding: 0.75rem var(--gutter) 1.25rem;
    border-bottom: 1px solid var(--line);
    background: var(--paper-raised);
    box-shadow: 0 18px 30px rgba(31, 29, 26, 0.08);
  }

  .site-nav[data-open="true"] {
    display: flex;
  }

  .site-nav a {
    padding: 0.85rem 0;
    border-bottom: 1px solid var(--line);
    font-size: 1rem;
  }

  .site-nav .nav-cta {
    display: inline-flex;
    justify-content: center;
    margin-top: 1rem;
    border-bottom: 0;
  }

  .header-actions {
    margin-left: auto;
  }

  .header-cta {
    display: none;
  }

  .icon-button {
    width: 44px;
    height: 44px;
  }

  .nav-toggle {
    display: inline-flex;
    width: auto;
    min-width: 44px;
    gap: 0.35rem;
    padding-inline: 0.65rem;
    font-family: var(--font-mono);
    font-size: 0.78rem;
    letter-spacing: 0.02em;
    white-space: nowrap;
  }

  .button-small,
  .button-quiet {
    min-height: 44px;
  }

  .copy-code {
    min-height: 44px;
    padding-inline: 0.65rem;
  }

  .sidebar-list a {
    min-height: 44px;
    align-items: center;
  }

  .footer-nav a {
    padding-block: 0.65rem;
  }
}

@media (max-width: 900px) {
  .editor-grid {
    grid-template-columns: 1fr;
  }

  .editor-code {
    min-height: 240px;
    border-right: 0;
    border-bottom: 1px solid var(--line);
  }

  .editor-preview iframe {
    min-height: 240px;
  }
}

@media (max-width: 720px) {
  .demo-body {
    grid-template-columns: 1fr;
  }

  .demo-code {
    min-height: 220px;
    border-right: 0;
    border-bottom: 1px solid var(--line);
    font-size: 16px;
  }

  .editor-code {
    font-size: 16px;
  }

  .course-row-link {
    grid-template-columns: 2rem minmax(0, 1fr) 1.25rem;
    gap: 0.75rem;
  }

  .course-index {
    grid-row: 1 / span 2;
  }

  .course-main {
    grid-column: 2;
    grid-row: 1;
  }

  .course-meta {
    display: none;
  }

  .course-row-link .status {
    grid-column: 2;
    grid-row: 2;
  }

  .course-arrow {
    grid-column: 3;
    grid-row: 1 / span 2;
  }

  .section-head {
    display: grid;
    gap: 0.75rem;
  }

  .section-head-note {
    max-width: 34rem;
  }

  .catalog-item {
    grid-template-columns: 2rem minmax(0, 1fr);
    gap: 0.75rem 1rem;
  }

  .catalog-index {
    grid-row: 1 / span 2;
  }

  .catalog-side {
    grid-column: 2;
  }

  .catalog-title {
    font-size: 1.55rem;
  }

  .fact-list > div {
    grid-template-columns: 1fr;
    gap: 0.3rem;
  }

  .footer-inner {
    grid-template-columns: 1fr;
    gap: 1.5rem;
  }

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

  .stat {
    border-bottom: 1px solid var(--line);
  }

  .stat:nth-child(2n) {
    padding-left: 1.25rem;
    border-right: 0;
  }

  .stat:nth-child(n + 3) {
    border-bottom: 0;
  }

  .progress-course {
    grid-template-columns: 1fr auto;
    gap: 0.5rem 1rem;
  }

  .progress-course-name {
    grid-column: 1;
  }

  .progress-course-meta {
    grid-column: 2;
  }

  .progress-course .progress {
    grid-column: 1 / -1;
  }

  .history-item {
    grid-template-columns: 1.5rem minmax(0, 1fr) auto;
  }

  .history-date {
    grid-column: 2;
    grid-row: 2;
  }

  .history-xp {
    grid-column: 3;
    grid-row: 1 / span 2;
  }

  .lesson-nav-next {
    margin-left: 0;
    text-align: left;
    justify-items: start;
  }

  .sidebar-list {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 980px) {
  .reward-grid {
    grid-template-columns: 1fr;
  }

  .certificate-list,
  .history-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (max-width: 720px) {
  .mission-item {
    grid-template-columns: 1.5rem minmax(0, 1fr);
    gap: 0.4rem 0.75rem;
  }

  .mission-meter,
  .mission-item > .button,
  .mission-item > .mission-claimed {
    grid-column: 2;
  }

  .mission-item > .button {
    justify-self: start;
  }

  .certificate-list,
  .history-grid {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 600px) {
  .header-inner {
    min-height: 60px;
    gap: 0.75rem;
  }

  .brand-word {
    font-size: 1.08rem;
  }

  .hero {
    padding-block: 2rem 3rem;
  }

  .hero-actions .button {
    flex: 1 1 100%;
  }

  .demo-head {
    align-items: flex-start;
  }

  .lesson-meta-row {
    gap: 0.6rem 0.9rem;
  }

  .finish-actions .button {
    flex: 1 1 100%;
  }

  .quiz-actions .button {
    flex: 1 1 100%;
  }

  .data-note .button {
    width: 100%;
  }

  .certificate {
    padding: 1.5rem;
  }

  .certificate-name {
    min-width: 0;
    width: 100%;
  }
}

@media print {
  @page {
    margin: 16mm;
  }

  body {
    background: #ffffff;
  }

  .site-header,
  .site-footer,
  .skip-link,
  .page-head,
  .certificate-actions,
  .certificate-locked,
  .toast {
    display: none;
  }

  #main {
    padding: 0;
  }

  .shell {
    width: 100%;
    max-width: none;
    margin: 0;
  }

  .certificate-wrap {
    padding: 0;
  }

  .certificate {
    max-width: none;
    min-height: 240mm;
    border-color: #1f1d1a;
    background: #ffffff;
    color: #1f1d1a;
    print-color-adjust: exact;
    -webkit-print-color-adjust: exact;
  }

  .certificate-mark {
    background: #b23a2f;
    color: #ffffff;
    print-color-adjust: exact;
    -webkit-print-color-adjust: exact;
  }

  .certificate-copy,
  .certificate-note,
  .certificate-meta dt,
  .certificate-for {
    color: #4a463f;
  }
}