@charset "UTF-8";
:root {
  --paper: #ffffff;
  --card: #ffffff;
  --ink: #171717;
  --muted: #292929;
  --line: #b8c1cc;
  --green: #003b70;
  --soft-green: #ffffff;
  --accent: #003b70;
  --serif: Georgia, "Times New Roman", "Songti SC", serif;
  --sans:
    Inter, -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
    "Microsoft YaHei", sans-serif;
}
* {
  box-sizing: border-box;
}
html {
  scroll-behavior: smooth;
  scroll-padding-top: 40px;
}
body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  overflow-wrap: anywhere;
  font: 1.375rem/1.75 var(--sans);
  padding-bottom: 110px;
}
a {
  color: inherit;
  text-underline-offset: 4px;
}
button,
input,
textarea {
  font: inherit;
}
button,
a,
input,
textarea,
summary {
  -webkit-tap-highlight-color: transparent;
}
button {
  cursor: pointer;
}
button:disabled {
  cursor: not-allowed;
}
button:focus-visible,
a:focus-visible,
summary:focus-visible {
  outline: 3px solid #005fcc;
  outline-offset: 5px;
}
input:focus,
textarea:focus {
  outline: 3px solid #005fcc;
  outline-offset: 2px;
}
h1,
h2,
h3,
p {
  margin: 0;
}
h2,
h3 {
  line-height: 1.25;
}
p + p {
  margin-top: 8px;
}
::selection {
  background: #cce3ff;
}
button {
  border: 0;
}
main {
  min-width: 0;
}
.site-header {
  max-width: 1280px;
  margin: auto;
  padding: 27px 44px 23px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  border-bottom: 1px solid var(--line);
}
.brand {
  display: flex;
  align-items: center;
  gap: 13px;
  text-decoration: none;
  font-size: 1.125rem;
  line-height: 1.35;
  letter-spacing: 1.5px;
}
.brand strong {
  display: block;
  font-weight: 500;
}
.brand-mark {
  font: italic 1.625rem var(--serif);
  background: var(--green);
  color: var(--paper);
  width: 37px;
  height: 40px;
  display: grid;
  place-items: center;
  border-radius: 3px;
}
.book-label {
  font-size: 1.125rem;
  letter-spacing: 1.5px;
  color: var(--muted);
}
.book-label span {
  padding: 0 12px;
  color: #292929;
}
.page-layout {
  max-width: 1192px;
  margin: auto;
  display: grid;
  grid-template-columns: minmax(0, 1fr) 270px;
  gap: 48px;
  padding: 0 0 28px;
}
.lesson-hero {
  padding: 61px 0 0;
}
.eyebrow {
  font-size: 1.125rem;
  font-weight: 650;
  letter-spacing: 2px;
  line-height: 1.5;
  color: var(--muted);
}
.lesson-hero > .eyebrow {
  display: flex;
  gap: 10px;
  align-items: center;
}
.lesson-hero > .eyebrow span {
  width: 7px;
  height: 7px;
  background: var(--accent);
  border-radius: 50%;
}
.lesson-hero h1 {
  font: normal clamp(52px, 6vw, 80px) / 1.13 var(--serif);
  letter-spacing: -3px;
  margin: 14px 0 1px;
}
.lesson-hero h1 > span {
  color: var(--accent);
}
.hero-translation {
  font: 1.5rem var(--serif);
  letter-spacing: 6px;
  color: var(--muted);
}
.hero-description {
  margin: 24px 0 27px;
  color: var(--muted);
  font-size: 1.375rem;
  line-height: 1.9;
}
.hero-description span {
  font-size: 1.125rem;
}
.hero-meta {
  display: flex;
  gap: 25px;
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  padding: 15px 0;
  font-size: 1.125rem;
  letter-spacing: 1.4px;
  color: var(--muted);
}
.lesson-section {
  padding-top: 48px;
  scroll-margin-top: 25px;
}
.section-heading {
  display: flex;
  gap: 19px;
  align-items: center;
  margin-bottom: 25px;
}
.section-number {
  font: italic 2.25rem var(--serif);
  color: #292929;
  line-height: 1;
  border-right: 1px solid var(--line);
  padding-right: 20px;
}
.section-heading .eyebrow {
  font-size: 1.125rem;
  letter-spacing: 1.7px;
  margin-bottom: 5px;
}
.section-heading h2 {
  font: normal 1.9375rem var(--serif);
}
h2 > span,
h3 > span {
  color: var(--muted);
  font: normal 1.125rem var(--sans);
  margin-left: 10px;
}
.reading-prompt {
  border-left: 3px solid var(--green);
  background: var(--soft-green);
  padding: 19px 23px;
}
.small-label {
  font-size: 1.125rem;
  letter-spacing: 1.5px;
  font-weight: 650;
  color: var(--green);
}
.reading-prompt > p {
  margin-top: 7px;
  font-size: 1.375rem;
}
.reading-prompt > p[lang] {
  font-size: 1.125rem;
  color: var(--muted);
}
.dialogue {
  padding: 14px 0 0;
  list-style: none;
  margin: 0;
}
.dialogue li {
  display: flex;
  gap: 25px;
  padding: 18px 22px;
  border-bottom: 1px solid var(--line);
}
.line-number {
  font: 1.125rem var(--sans);
  color: #292929;
  padding-top: 9px;
}
.spoken {
  font: 1.875rem/1.6 var(--sans);
}
.translation {
  font-size: 1.125rem;
  color: var(--muted);
  margin-top: 3px;
}
.reading-answer {
  padding: 22px;
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 3px;
  margin-top: 24px;
}
.reading-answer .question {
  padding: 0;
  border: none;
}
.lesson-notes,
.vocabulary-block {
  margin-top: 38px;
}
h3 {
  font-size: 1.375rem;
  font-weight: 550;
  letter-spacing: -0.2px;
}
.note-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 28px;
  margin-top: 18px;
}
.note-grid > div {
  border-top: 1px solid var(--line);
  padding-top: 16px;
}
.note-grid p {
  font-size: 1.375rem;
  color: var(--muted);
  margin-top: 9px;
  line-height: 1.9;
}
.vocabulary {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0 28px;
  margin: 20px 0 0;
}
.vocabulary > div {
  padding: 14px 0;
  border-top: 1px solid var(--line);
}
.vocabulary dt {
  font-weight: 600;
  font-size: 1.375rem;
}
.phonetic {
  font-family: var(--sans);
  font-size: 1.125rem;
  font-weight: 400;
  color: var(--muted);
  margin-left: 8px;
}
.vocabulary dd {
  margin: 3px 0 0;
  font-size: 1.125rem;
  color: var(--muted);
}
.word-type {
  font-style: italic;
}
.exercise {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 5px;
  padding: 29px 30px;
  margin-bottom: 20px;
}
.exercise-heading {
  padding-bottom: 22px;
  border-bottom: 1px solid var(--line);
  margin-bottom: 5px;
}
.exercise-heading h3 {
  font: normal 1.5rem var(--serif);
}
.exercise-heading p {
  font-size: 1.125rem;
  color: var(--muted);
  margin-top: 7px;
}
.exercise-heading .instruction {
  font-size: 1.375rem;
  color: var(--ink);
  margin-top: 10px;
}
.question {
  padding: 18px 0;
  border-bottom: 1px solid #cbd2d9;
  min-width: 0;
  position: relative;
}
.question:last-child {
  border-bottom: 0;
}
.question label {
  display: flex;
  gap: 11px;
  font-size: 1.375rem;
  margin-bottom: 10px;
  line-height: 1.65;
  align-items: baseline;
}
.question-number {
  flex-shrink: 0;
  font-size: 1.125rem;
  letter-spacing: 0.5px;
  color: #292929;
  min-width: 16px;
}
.question input,
.question textarea {
  width: 100%;
  min-width: 0;
  border: 2px solid #595959;
  background: #ffffff;
  border-radius: 3px;
  padding: 10px 12px;
  color: var(--ink);
  font-size: 1.375rem;
  transition:
    background 0.15s,
    border-color 0.15s;
  min-height: 46px;
}
.question input::placeholder,
.question textarea::placeholder {
  color: #292929;
  font-size: 1.125rem;
}
.question input:focus,
.question textarea:focus {
  background: #fff;
}
.question textarea {
  resize: vertical;
}
.question-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 0 25px;
}
.question-grid .question {
  border-bottom: 1px solid #cbd2d9;
}
.example input[readonly],
.example textarea[readonly] {
  background: var(--soft-green);
  border-color: #595959;
  color: var(--green);
  font-style: normal;
}
.example-label {
  font-size: 1.125rem;
  color: var(--green);
  display: block;
  margin-top: 5px;
  letter-spacing: 0.4px;
}
.word-bank {
  display: flex;
  flex-wrap: wrap;
  gap: 7px;
  margin: 19px 0 5px;
  padding: 13px;
  background: #ffffff;
  border-radius: 3px;
}
.word-bank span {
  font: 1.375rem/1.6 var(--sans);
  padding: 5px 10px;
  background: var(--card);
  border: 2px solid #595959;
  border-radius: 3px;
}
.numbers {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}
.numbers .question label {
  font: 1.375rem/1.6 var(--sans);
}
.section-intro {
  font-size: 1.125rem;
  color: var(--muted);
  margin: -8px 0 23px;
}
.source-section {
  margin-top: 42px;
  padding-top: 30px;
  border-top: 1px solid var(--line);
  scroll-margin-top: 30px;
}
.source-section h2 {
  font: normal 1.625rem var(--serif);
  margin-top: 7px;
}
.source-section > p:not(.eyebrow) {
  font-size: 1.125rem;
  color: var(--muted);
  margin-top: 12px;
}
.source-links {
  padding: 0;
  list-style: none;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0 24px;
  margin-top: 20px;
}
.source-links a {
  font-size: 1.125rem;
  text-decoration: none;
  display: flex;
  justify-content: space-between;
  gap: 16px;
  padding: 14px 0;
  border-bottom: 1px solid var(--line);
}
.source-links a:hover {
  color: var(--accent);
}
.source-links a > span {
  white-space: nowrap;
  font-size: 1.125rem;
  color: var(--muted);
}
.end-note {
  text-align: center;
  color: var(--muted);
  font: italic 1.375rem var(--serif);
  margin: 45px 0 25px;
}
.end-note span {
  font: 1.125rem var(--sans);
  display: block;
  margin-top: 5px;
}
.navigation-rail {
  position: sticky;
  top: 36px;
  align-self: start;
  padding-top: 62px;
}
.navigation-rail details {
  border: 1px solid var(--line);
  border-radius: 5px;
  background: var(--card);
  box-shadow: 0 6px 25px #24342405;
  overflow: hidden;
}
.navigation-rail summary {
  padding: 20px 20px 17px;
  cursor: pointer;
  list-style: none;
  font-size: 1.125rem;
  font-weight: 650;
  letter-spacing: 1.4px;
  text-transform: uppercase;
}
.navigation-rail summary::-webkit-details-marker {
  display: none;
}
.navigation-rail summary > span {
  float: right;
  color: var(--muted);
}
.navigation-rail nav {
  padding: 0 10px 13px;
}
.navigation-rail nav > a {
  display: flex;
  gap: 12px;
  align-items: center;
  padding: 13px 10px;
  text-decoration: none;
  border-radius: 3px;
  font-size: 1.375rem;
  position: relative;
}
.navigation-rail nav > a > span:first-child {
  color: var(--muted);
  font-size: 1.125rem;
}
.navigation-rail nav small {
  display: block;
  font-size: 1.125rem;
  color: var(--muted);
  margin-top: 2px;
}
.navigation-rail nav > a[aria-current] {
  background: var(--soft-green);
  color: var(--green);
  box-shadow: inset 3px 0 0 var(--green);
  font-weight: 650;
}
.nav-dot {
  width: 5px;
  height: 5px;
  border-radius: 50%;
  background: transparent;
  margin-left: auto;
}
.navigation-rail nav > a[aria-current] .nav-dot {
  background: var(--green);
}
.rail-progress {
  padding: 20px;
  border-top: 1px solid var(--line);
}
.rail-progress p {
  margin: 5px 0 9px;
}
.rail-progress strong {
  font: normal 1.6875rem var(--serif);
}
.rail-progress p > span {
  font-size: 1.125rem;
  color: var(--muted);
}
progress {
  display: block;
  appearance: none;
  width: 100%;
  height: 4px;
  border: none;
  background: #d1d5db;
  border-radius: 4px;
  overflow: hidden;
}
progress::-webkit-progress-bar {
  background: #d1d5db;
}
progress::-webkit-progress-value {
  background: var(--green);
}
progress::-moz-progress-bar {
  background: var(--green);
}
.rail-progress > small {
  font-size: 1.125rem;
  color: var(--muted);
  display: block;
  margin-top: 12px;
}
.sources-shortcut {
  font-size: 1.125rem;
  color: var(--muted);
  display: block;
  text-decoration: none;
  padding: 0 20px 20px;
}
.bottom-bar {
  position: fixed;
  bottom: 0;
  left: 0;
  right: 0;
  z-index: 20;
  background: #ffffff;

  border-top: 1px solid var(--line);
  padding: 14px 24px max(14px, env(safe-area-inset-bottom));
  padding-bottom: max(14px, env(safe-area-inset-bottom));
}
.bottom-inner {
  max-width: 1192px;
  margin: auto;
  display: grid;
  grid-template-columns: 1fr 1.35fr 1fr 1fr;
  align-items: center;
}
.page-step {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
}
.page-step.next {
  align-items: flex-end;
}
.page-step button,
.page-step a {
  background: transparent;
  color: var(--green);
  padding: 6px 0;
  font-size: 1.375rem;
  font-weight: 600;
}
.page-step button:disabled {
  color: #292929;
}
.page-step small,
.submit-action small {
  font-size: 1.125rem;
  color: var(--muted);
  margin-top: 2px;
}
.submit-action {
  display: flex;
  flex-direction: column;
  align-items: center;
}
.submit-action button {
  padding: 11px 29px;
  background: var(--green);
  color: white;
  min-width: 165px;
  border-radius: 4px;
  font-size: 1.375rem;
  font-weight: 550;
  transition: background 0.15s;
}
.submit-action button:hover {
  background: #123c65;
}
.submit-action button:disabled {
  opacity: 0.7;
}
.submit-action button > span {
  margin-left: 25px;
}
.toast {
  position: fixed;
  bottom: 112px;
  left: 50%;
  transform: translateX(-50%);
  background: var(--green);
  color: white;
  border-radius: 5px;
  padding: 13px 21px;
  z-index: 40;
  font-size: 1.375rem;
  box-shadow: 0 6px 25px #23332620;
  max-width: calc(100vw - 32px);
  text-align: center;
}
.toast[hidden] {
  display: none;
}
dialog {
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 28px;
  width: min(650px, calc(100vw - 32px));
  color: var(--ink);
  background: var(--card);
  max-height: 85dvh;
}
dialog::backdrop {
  background: #16291b88;
}
dialog h2 {
  font: 1.75rem var(--serif);
}
dialog p {
  font-size: 1.375rem;
  color: var(--muted);
  margin: 12px 0 18px;
}
dialog textarea {
  width: 100%;
  font: 1.125rem/1.7 monospace;
  padding: 12px;
  resize: vertical;
  border: 1px solid var(--line);
  border-radius: 3px;
  max-height: 45dvh;
}
.dialog-actions {
  display: flex;
  justify-content: flex-end;
  gap: 12px;
  margin-top: 14px;
}
.dialog-actions button {
  padding: 9px 18px;
  background: var(--soft-green);
  border-radius: 4px;
  color: var(--green);
}
.dialog-actions button:last-child {
  background: var(--green);
  color: white;
}
.skip-link {
  position: fixed;
  top: -100px;
  left: 20px;
  padding: 10px 20px;
  background: var(--green);
  color: white;
  z-index: 50;
}
.skip-link:focus {
  top: 12px;
}
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}
.noscript-note {
  margin: 20px;
  padding: 20px;
  border: 1px solid var(--line);
}
@media (min-width: 1500px) {
  .page-layout {
    gap: 90px;
  }
}
@media (max-width: 1270px) {
  .page-layout {
    margin: 0 44px;
    gap: 38px;
    grid-template-columns: minmax(0, 1fr) 270px;
  }
}
@media (max-width: 960px) {
  .page-layout {
    margin: 0 28px;
    grid-template-columns: minmax(0, 1fr);
    gap: 0;
  }
  .site-header {
    padding: 22px 28px;
  }
  .lesson-hero {
    padding-top: 46px;
  }
  .navigation-rail {
    position: fixed;
    right: 20px;
    top: 18px;
    z-index: 30;
    padding: 0;
    width: 195px;
    max-height: calc(100dvh - 125px);
    overflow-y: auto;
    box-shadow: 0 4px 15px #2434240a;
  }
  .navigation-rail summary {
    padding: 13px 15px;
  }
  .book-label {
    display: none;
  }
  .exercise {
    padding: 25px;
  }
  .lesson-hero h1 {
    font-size: 4.25rem;
  }
  .lesson-section {
    scroll-margin-top: 68px;
  }
  .source-section {
    scroll-margin-top: 68px;
  }
}
@media (max-width: 580px) {
  body {
    padding-bottom: 108px;
  }
  .site-header {
    padding: 19px 20px;
  }
  .brand {
    font-size: 1.125rem;
    gap: 9px;
    letter-spacing: 1px;
  }
  .brand-mark {
    width: 29px;
    height: 33px;
    font-size: 1.5rem;
  }
  .page-layout {
    margin: 0 20px;
  }
  .navigation-rail {
    right: 16px;
    top: 19px;
    width: 145px;
  }
  .navigation-rail summary {
    font-size: 1.125rem;
    padding: 10px 12px;
    letter-spacing: 0.5px;
  }
  .lesson-hero {
    padding-top: 37px;
  }
  .lesson-hero h1 {
    font-size: 3.5625rem;
    letter-spacing: -2px;
  }
  .hero-translation {
    font-size: 1.5rem;
  }
  .hero-meta {
    gap: 12px;
    font-size: 1.125rem;
    letter-spacing: 0.65px;
    flex-wrap: wrap;
  }
  .hero-description {
    font-size: 1.125rem;
    margin: 21px 0;
  }
  .lesson-section {
    padding-top: 35px;
  }
  .section-heading {
    gap: 14px;
    margin-bottom: 20px;
  }
  .section-heading h2 {
    font-size: 1.75rem;
  }
  .section-number {
    font-size: 2rem;
    padding-right: 15px;
  }
  .reading-prompt {
    padding: 16px;
  }
  .reading-prompt > p {
    font-size: 1.375rem;
  }
  .dialogue li {
    padding: 16px 5px;
    gap: 17px;
  }
  .spoken {
    font-size: 1.5rem;
  }
  .note-grid,
  .vocabulary,
  .question-grid,
  .source-links {
    grid-template-columns: 1fr;
    gap: 0;
  }
  .note-grid {
    gap: 18px;
  }
  .vocabulary-block h3 {
    font-size: 1.375rem;
  }
  .vocabulary-block h3 > span {
    display: block;
    margin: 7px 0 0;
    font-size: 1.125rem;
  }
  .exercise {
    padding: 20px 17px;
  }
  .exercise-heading h3 {
    font-size: 1.5rem;
  }
  .exercise-heading {
    padding-bottom: 18px;
  }
  .question {
    padding: 16px 0;
  }
  .question label {
    font-size: 1.375rem;
  }
  .question input,
  .question textarea {
    font-size: 1.375rem;
  }
  .numbers {
    grid-template-columns: 1fr 1fr;
    gap: 0 16px;
  }
  .word-bank {
    padding: 10px;
    gap: 5px;
  }
  .word-bank span {
    font-size: 1.375rem;
    padding: 4px 8px;
  }
  .bottom-bar {
    padding-left: 12px;
    padding-right: 12px;
  }
  .bottom-inner {
    grid-template-columns: 1fr 1.25fr 1fr 1fr;
    gap: 6px;
  }
  .submit-action button {
    min-width: 0;
    width: 100%;
    padding: 10px 14px;
  }
  .submit-action button > span {
    margin-left: 13px;
  }
  .page-step button,
  .page-step a {
    font-size: 1.125rem;
  }
  .page-step small {
    font-size: 1.125rem;
    max-width: 95px;
  }
  .next small {
    text-align: right;
  }
  .submit-action small {
    font-size: 1.125rem;
    white-space: nowrap;
  }
  .end-note {
    font-size: 1.375rem;
  }
  h2 > span {
    font-size: 1.125rem;
  }
  .rail-progress {
    padding: 15px;
  }
  .source-links {
    margin-top: 16px;
  }
}
@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
  * {
    transition: none !important;
  }
}
@media print {
  body {
    padding: 0;
    background: white;
    color: black;
  }
  .navigation-rail,
  .bottom-bar,
  .toast,
  .hero-description,
  .skip-link,
  .end-note {
    display: none;
  }
  .page-layout {
    display: block;
    margin: 0;
  }
  .site-header {
    padding: 12px 0;
  }
  .lesson-hero {
    padding-top: 20px;
  }
  .lesson-hero h1 {
    font-size: 2.75rem;
  }
  .exercise,
  .reading-answer {
    break-inside: avoid;
    background: white;
  }
  .question input {
    background: white;
    border: 0;
    border-bottom: 1px solid #aaa;
  }
  .source-links a {
    font-size: 1.125rem;
  }
  a {
    text-decoration: none;
  }
}

/* White reading surfaces and explicit visual cues for low-vision readability. */
.reading-prompt {
  border: 1px solid var(--line);
  border-left: 4px solid var(--green);
}
.word-bank {
  border: 1px solid var(--line);
}
.example input[readonly],
.example textarea[readonly] {
  border-style: dashed;
}
.source-links a {
  text-decoration: underline;
}
.rail-progress > small,
.translation,
.note-grid p,
.vocabulary dd,
.exercise-heading p,
.source-section > p:not(.eyebrow),
.section-intro {
  font-size: 1.375rem;
}
.hero-description span {
  font-size: 1.375rem;
}
.page-step button,
.page-step a {
  font-size: 1.375rem;
}
.page-step small,
.submit-action small {
  font-size: 1.125rem;
}
@media (max-width: 580px) {
  .brand {
    letter-spacing: 0;
  }
  .navigation-rail summary {
    letter-spacing: 0;
  }
  .bottom-inner {
    grid-template-columns: 1fr 1.25fr 1fr;
  }
  .submit-action small {
    white-space: normal;
    text-align: center;
    line-height: 1.35;
  }
  .page-step small {
    max-width: 90px;
    line-height: 1.35;
  }
  .hero-meta {
    font-size: 1.125rem;
    letter-spacing: 0;
  }
}

/* Large reading text stays large on small screens; layout reflows around it. */
.hero-description,
.hero-description span,
.reading-prompt > p,
.reading-prompt > p[lang],
.translation,
.note-grid p,
.vocabulary dt,
.vocabulary dd,
.exercise-heading p,
.exercise-heading .instruction,
.question label,
.question input,
.question textarea,
.section-intro,
.source-section > p:not(.eyebrow) {
  font-size: 1.375rem;
  line-height: 1.75;
}
.spoken {
  font-size: 1.875rem;
}
.question input::placeholder,
.question textarea::placeholder {
  font-size: 1.125rem;
  opacity: 1;
}
.question input,
.question textarea {
  min-height: 60px;
}
.question label > span:last-child {
  min-width: 0;
}
.brand,
.eyebrow,
.small-label,
.hero-meta,
.navigation-rail summary {
  letter-spacing: 0.025em;
}
.source-links a {
  color: var(--green);
}
.navigation-rail summary {
  text-transform: none;
}
.navigation-rail nav > a {
  min-height: 64px;
}
.navigation-rail {
  max-height: calc(100dvh - 160px);
  overflow-y: auto;
}
.dialog-actions {
  flex-wrap: wrap;
}
.dialog-actions button {
  border: 2px solid var(--green);
}
body {
  padding-bottom: 170px;
}
.toast {
  bottom: 175px;
}
@media (max-width: 1100px) {
  .question-grid,
  .note-grid,
  .vocabulary,
  .source-links {
    grid-template-columns: 1fr;
  }
}
@media (max-width: 960px) {
  .navigation-rail {
    width: 260px;
    max-width: calc(100vw - 32px);
    top: 16px;
  }
  .site-header {
    padding-top: 100px;
  }
  .navigation-rail summary {
    font-size: 1.125rem;
    min-height: 52px;
  }
}
@media (max-width: 580px) {
  .page-layout {
    margin: 0 16px;
  }
  .exercise {
    padding: 20px 14px;
  }
  .bottom-bar {
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    z-index: 20;
    padding: 10px 12px max(10px, env(safe-area-inset-bottom));
  }
  body {
    padding-bottom: 120px;
  }
  .bottom-inner {
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 6px;
    align-items: start;
  }
  .page-step button,
  .submit-action button {
    font-size: 1.125rem;
    min-height: 52px;
  }
  .page-step button,
  .page-step a {
    display: flex;
    flex-wrap: wrap;
    gap: 2px;
  }
  .next button,
  .next a {
    justify-content: flex-end;
  }
  .submit-action button {
    padding: 10px 6px;
  }
  .submit-action button > span {
    display: none;
  }
  .page-step small,
  .submit-action small {
    font-size: 1.125rem;
  }
  .toast {
    bottom: 16px;
    width: calc(100vw - 32px);
  }
  .source-links a {
    flex-wrap: wrap;
  }
  .question-grid {
    grid-template-columns: 1fr;
  }
  h2 > span,
  h3 > span {
    display: block;
    margin: 8px 0 0;
  }
  .dialogue li {
    gap: 12px;
  }
  dialog {
    padding: 20px;
  }
}
@media print {
  body {
    padding-bottom: 0;
  }
  .bottom-bar {
    display: none;
  }
}

.section-heading > div,
.dialogue li > div {
  min-width: 0;
}
.page-step button,
.page-step a,
.submit-action button {
  max-width: 100%;
}

.page-step a {
  text-decoration: underline;
  display: inline-flex;
  align-items: center;
  gap: 0.3em;
  min-height: 52px;
}

/* Individual source illustrations sit beside their matching answer fields. */
.illustrated-question {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1.3fr);
  align-items: center;
  gap: 24px;
  padding: 24px 0;
  border-bottom: 1px solid var(--line);
}
.illustrated-question:last-child {
  border-bottom: 0;
}
.illustrated-question > .question {
  padding: 0;
  border: 0;
}
.question-illustration {
  margin: 0;
  min-width: 0;
}
.question-illustration img {
  display: block;
  width: 100%;
  height: auto;
  border: 1px solid #595959;
}
.question-illustration figcaption {
  margin-top: 8px;
  font-size: 1.125rem;
  color: var(--muted);
}
@media (max-width: 700px) {
  .illustrated-question {
    grid-template-columns: minmax(0, 1fr);
    gap: 16px;
  }
}
@media print {
  .illustrated-question {
    break-inside: avoid;
  }
}

.dialogue-scene .dialogue {
  padding-top: 0;
  min-width: 0;
}
.dialogue-scene .dialogue li {
  padding: 12px 0;
  gap: 12px;
}
.dialogue-scene .dialogue li:last-child {
  border-bottom: 0;
}

/* Keep long model answers and typed sentences visible as text size increases. */
.question textarea {
  field-sizing: content;
  min-height: 3lh;
}

.dialogue .line-number {
  flex-shrink: 0;
  white-space: nowrap;
}