:root {
  color-scheme: light dark;
  --page: light-dark(#f4f1e9, #111716);
  --surface: light-dark(#fffdf8, #19201f);
  --surface-soft: light-dark(#ece8dd, #232c2a);
  --text: light-dark(#18201e, #f2f6f3);
  --muted: light-dark(#5d6965, #aebbb7);
  --line: light-dark(#d5d0c4, #35423f);
  --accent: light-dark(#176b5a, #70d0b6);
  --accent-strong: light-dark(#0d4d40, #9ae6d1);
  --accent-soft: light-dark(#d8eee7, #193b34);
  --warm: light-dark(#bf6b3b, #f0a779);
  --success: light-dark(#176b5a, #70d0b6);
  --danger: light-dark(#a43e35, #ff958c);
  --shadow: 0 18px 50px light-dark(rgba(45, 54, 50, 0.08), rgba(0, 0, 0, 0.25));
  --radius: 20px;
  font-family: Inter, "Hiragino Sans", "Yu Gothic", Meiryo, sans-serif;
}

* {
  box-sizing: border-box;
}

[hidden] {
  display: none !important;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background:
    radial-gradient(circle at 10% 0%, light-dark(rgba(23, 107, 90, 0.10), rgba(112, 208, 182, 0.08)), transparent 34rem),
    var(--page);
  color: var(--text);
  line-height: 1.7;
}

button,
select,
textarea {
  font: inherit;
}

button,
select {
  min-height: 44px;
}

button {
  cursor: pointer;
}

a {
  color: var(--accent-strong);
}

.skip-link {
  position: absolute;
  left: 1rem;
  top: -5rem;
  z-index: 20;
  padding: 0.75rem 1rem;
  background: var(--surface);
  color: var(--text);
  border: 1px solid var(--line);
  border-radius: 10px;
}

.skip-link:focus {
  top: 1rem;
}

.course-shell {
  width: min(1180px, calc(100% - 32px));
  margin: 0 auto;
  padding: 40px 0 72px;
}

.course-header {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(260px, 360px);
  gap: 36px;
  align-items: end;
  margin-bottom: 28px;
}

.eyebrow,
.section-label {
  margin: 0 0 4px;
  color: var(--accent-strong);
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

h1,
h2,
h3,
p {
  overflow-wrap: anywhere;
}

h1 {
  margin: 0;
  font-size: clamp(2rem, 5vw, 4.4rem);
  line-height: 1.05;
  letter-spacing: -0.045em;
}

h2 {
  margin: 0;
  font-size: clamp(1.65rem, 4vw, 2.65rem);
  line-height: 1.18;
  letter-spacing: -0.025em;
}

h3 {
  margin: 0 0 14px;
  font-size: 1.08rem;
}

.course-subtitle,
.lesson-goal {
  max-width: 68ch;
  margin: 12px 0 0;
  color: var(--muted);
}

.progress-summary {
  padding-bottom: 6px;
}

.header-tools {
  display: grid;
  gap: 18px;
}

.account-panel {
  display: grid;
  gap: 12px;
  padding: 15px;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 14px;
  box-shadow: var(--shadow);
}

.account-copy {
  display: grid;
  gap: 2px;
}

.account-copy strong {
  font-size: 0.9rem;
}

.account-copy span {
  color: var(--muted);
  font-size: 0.78rem;
  line-height: 1.45;
}

.account-copy span.is-error {
  color: var(--danger);
}

.google-button {
  min-height: 44px;
}

.account-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  align-items: center;
}

.compact-button {
  min-height: 38px;
  padding: 5px 11px;
  font-size: 0.82rem;
}

.account-actions .text-button {
  min-height: 38px;
  margin: 0;
  font-size: 0.78rem;
}

.danger-button {
  color: var(--danger);
}

.progress-label {
  display: flex;
  justify-content: space-between;
  gap: 16px;
  margin-bottom: 8px;
  font-size: 0.9rem;
}

.progress-track {
  height: 10px;
  overflow: hidden;
  background: var(--surface-soft);
  border-radius: 999px;
}

.progress-fill {
  width: 0;
  height: 100%;
  background: var(--accent);
  border-radius: inherit;
  transition: width 240ms ease;
}

.course-layout {
  display: grid;
  grid-template-columns: 250px minmax(0, 1fr);
  gap: 28px;
  align-items: start;
}

.course-nav {
  position: sticky;
  top: 18px;
}

.week-group + .week-group {
  margin-top: 22px;
}

.week-heading {
  margin: 0 0 7px;
  color: var(--muted);
  font-size: 0.78rem;
  letter-spacing: 0.06em;
}

.day-list {
  display: grid;
  gap: 4px;
}

.day-button {
  display: grid;
  grid-template-columns: 2.25rem minmax(0, 1fr) 18px;
  gap: 8px;
  align-items: center;
  width: 100%;
  padding: 8px 10px;
  color: var(--muted);
  text-align: left;
  background: transparent;
  border: 0;
  border-radius: 10px;
}

.day-button:hover {
  background: var(--surface-soft);
  color: var(--text);
}

.day-button[aria-current="page"] {
  background: var(--accent-soft);
  color: var(--text);
}

.day-number {
  font-variant-numeric: tabular-nums;
  color: var(--accent-strong);
  font-weight: 700;
}

.day-name {
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
  font-size: 0.86rem;
}

.day-check {
  color: var(--success);
  font-weight: 700;
}

.mobile-day-label,
.mobile-day-select {
  display: none;
}

.text-button {
  margin-top: 24px;
  padding: 6px 0;
  color: var(--muted);
  background: transparent;
  border: 0;
  text-decoration: underline;
  text-underline-offset: 3px;
}

.lesson-main {
  min-width: 0;
}

.lesson-pager {
  display: grid;
  grid-template-columns: auto 1fr auto;
  gap: 12px;
  align-items: center;
  margin-bottom: 12px;
}

.day-position {
  color: var(--muted);
  text-align: center;
  font-size: 0.86rem;
}

.lesson-card {
  padding: clamp(22px, 5vw, 52px);
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

.lesson-card > section {
  margin-top: 34px;
  padding-top: 30px;
  border-top: 1px solid var(--line);
}

.video-materials {
  display: grid;
  gap: 22px;
}

.video-materials:empty {
  display: none;
}

.video-card h4 {
  margin: 0 0 10px;
  font-size: 0.95rem;
}

.video-frame {
  position: relative;
  overflow: hidden;
  aspect-ratio: 16 / 9;
  background: #000;
  border-radius: 14px;
}

.video-frame iframe {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  border: 0;
}

.video-fallback {
  display: inline-block;
  margin-top: 8px;
  color: var(--muted);
  font-size: 0.82rem;
  text-underline-offset: 3px;
}

.reading-panel {
  margin-top: 0;
}

.inline-video-section {
  margin-top: 26px;
  padding-top: 24px;
  border-top: 1px solid var(--line);
}

.inline-video-section h4 {
  margin: 0 0 14px;
  font-size: 1rem;
}

.markdown-body {
  padding: clamp(18px, 4vw, 32px);
  background: var(--page);
  border-radius: 14px;
}

.inline-reading-block + .inline-reading-block {
  margin-top: 34px;
  padding-top: 30px;
  border-top: 1px solid var(--line);
}

.inline-reading-label {
  display: inline-flex;
  margin: 0 0 10px;
  padding: 4px 10px;
  color: var(--accent-strong);
  background: var(--accent-soft);
  border-radius: 999px;
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.03em;
}

.inline-reading-block.is-overview {
  padding-bottom: 4px;
}

.markdown-body:empty {
  display: none;
}

.markdown-body h1,
.markdown-body h2,
.markdown-body h3,
.markdown-body h4 {
  margin: 1.6em 0 0.55em;
  line-height: 1.35;
  letter-spacing: -0.015em;
}

.markdown-body h1:first-child,
.markdown-body h2:first-child,
.markdown-body h3:first-child,
.markdown-body h4:first-child {
  margin-top: 0;
}

.markdown-body h1 {
  font-size: 1.5rem;
}

.markdown-body h2 {
  font-size: 1.3rem;
}

.markdown-body h3 {
  font-size: 1.12rem;
}

.markdown-body h4 {
  font-size: 1rem;
}

.markdown-body p,
.markdown-body ul,
.markdown-body ol,
.markdown-body blockquote,
.markdown-body pre,
.markdown-body .markdown-table-wrap {
  margin: 0.8em 0;
}

.markdown-body ul,
.markdown-body ol {
  padding-left: 1.45rem;
}

.markdown-body li + li {
  margin-top: 0.32em;
}

.markdown-body blockquote {
  padding: 2px 0 2px 16px;
  color: var(--muted);
  border-left: 4px solid var(--warm);
}

.markdown-body code {
  padding: 0.12em 0.35em;
  background: var(--surface-soft);
  border-radius: 5px;
}

.markdown-body pre {
  overflow-x: auto;
  padding: 14px;
  background: var(--surface-soft);
  border-radius: 10px;
}

.markdown-body pre code {
  padding: 0;
  background: transparent;
}

.markdown-body img {
  display: block;
  max-width: 100%;
  height: auto;
  margin: 18px auto;
  border-radius: 10px;
}

.markdown-table-wrap {
  overflow-x: auto;
}

.markdown-body table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.9rem;
}

.markdown-body th,
.markdown-body td {
  padding: 9px 10px;
  text-align: left;
  vertical-align: top;
  border-bottom: 1px solid var(--line);
}

.markdown-body th {
  color: var(--accent-strong);
}

.material-error {
  color: var(--danger);
}

.lesson-heading {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  gap: 24px;
  align-items: start;
}

.primary-button,
.secondary-button,
.complete-button {
  padding: 9px 15px;
  border-radius: 10px;
  border: 1px solid var(--line);
}

.primary-button,
.complete-button[aria-pressed="true"] {
  background: var(--accent);
  border-color: var(--accent);
  color: light-dark(#ffffff, #0c1714);
}

.secondary-button,
.complete-button {
  background: transparent;
  color: var(--text);
}

.primary-button:hover,
.complete-button[aria-pressed="true"]:hover {
  background: var(--accent-strong);
}

.secondary-button:hover,
.complete-button:hover {
  background: var(--surface-soft);
}

button:disabled {
  cursor: not-allowed;
  opacity: 0.42;
}

.timer-panel {
  display: grid;
  grid-template-columns: 1fr auto auto;
  gap: 22px;
  align-items: center;
  padding: 20px 0 0;
}

.timer-phase {
  margin: 0;
  font-weight: 700;
}

.timer-display {
  margin: 0;
  font-size: clamp(2rem, 6vw, 3.2rem);
  font-weight: 700;
  font-variant-numeric: tabular-nums;
  letter-spacing: -0.04em;
}

.timer-actions {
  display: flex;
  gap: 8px;
}

.section-heading-row {
  display: flex;
  justify-content: space-between;
  gap: 20px;
  align-items: baseline;
}

.steps-status,
.notes-status {
  color: var(--muted);
  font-size: 0.84rem;
}

.steps-introduction {
  margin: 0 0 16px;
  color: var(--muted);
  font-size: 0.9rem;
}

.lesson-steps {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 14px;
}

.step-overview-item {
  position: relative;
  padding: 17px;
  background: var(--surface-soft);
  border: 1px solid transparent;
  border-radius: 14px;
}

.step-overview-item.is-complete,
.lesson-response-section.is-complete {
  border-color: color-mix(in srgb, var(--accent) 38%, transparent);
}

.step-overview-number {
  display: block;
  margin-bottom: 5px;
  color: var(--accent-strong);
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.step-overview-item strong {
  display: block;
}

.step-overview-item p {
  margin: 6px 0 30px;
  color: var(--muted);
  font-size: 0.86rem;
}

.step-overview-status {
  position: absolute;
  left: 17px;
  bottom: 14px;
  color: var(--muted);
  font-size: 0.72rem;
  font-weight: 700;
}

.step-overview-status.is-complete,
.step-section-status.is-complete {
  color: var(--accent-strong);
}

.step-section-status {
  flex: 0 0 auto;
  padding: 3px 9px;
  color: var(--muted);
  background: var(--surface-soft);
  border-radius: 999px;
  font-size: 0.72rem;
  font-weight: 700;
  white-space: nowrap;
}

.step-section-status.is-complete {
  background: var(--accent-soft);
}

.lesson-response-sections {
  display: grid;
}

.lesson-response-section {
  margin-top: 34px;
  padding: 30px clamp(16px, 3vw, 28px) 26px;
  background: color-mix(in srgb, var(--surface-soft) 58%, transparent);
  border: 1px solid var(--line);
  border-radius: 16px;
}

.step-response-instruction {
  margin: 4px 0 0;
  color: var(--muted);
}

.step-answer-label {
  display: block;
  margin: 18px 0 7px;
  font-size: 0.82rem;
  font-weight: 700;
}

.step-response {
  min-height: 148px;
  background: var(--surface);
}

.step-response-footer {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  margin-top: 7px;
  color: var(--muted);
  font-size: 0.72rem;
}

.output-panel {
  position: relative;
}

.output-panel::before {
  content: "";
  position: absolute;
  left: 0;
  top: 30px;
  bottom: 0;
  width: 4px;
  background: var(--warm);
  border-radius: 999px;
}

.output-panel h3,
.output-panel p {
  margin-left: 18px;
}

.output-heading-row {
  align-items: center;
}

.output-step-label {
  padding: 3px 9px;
  color: var(--warm);
  background: color-mix(in srgb, var(--warm) 12%, transparent);
  border-radius: 999px;
  font-size: 0.72rem;
  font-weight: 700;
  white-space: nowrap;
}

.output-introduction {
  margin-top: 0;
  color: var(--muted);
  font-size: 0.86rem;
}

.lesson-output {
  margin-top: 6px;
  font-size: clamp(1.08rem, 2.5vw, 1.32rem);
  font-weight: 700;
}

.output-panel p {
  margin-bottom: 0;
}

.quiz-introduction {
  margin: -4px 0 18px;
  color: var(--muted);
  font-size: 0.9rem;
}

.quiz-form fieldset {
  margin: 0 0 18px;
  padding: 0;
  border: 0;
}

.quiz-form legend {
  margin-bottom: 12px;
  font-weight: 700;
}

.quiz-choices {
  display: grid;
  gap: 8px;
}

.quiz-choice {
  display: flex;
  gap: 10px;
  align-items: center;
  min-height: 44px;
  padding: 8px 12px;
  background: var(--surface-soft);
  border-radius: 10px;
  cursor: pointer;
}

.quiz-choice input {
  width: 18px;
  height: 18px;
  accent-color: var(--accent);
}

.quiz-result {
  min-height: 1.7em;
  margin: 12px 0 0;
}

.quiz-result.is-correct {
  color: var(--success);
}

.quiz-result.is-wrong {
  color: var(--danger);
}

textarea {
  width: 100%;
  resize: vertical;
  padding: 13px 14px;
  color: var(--text);
  background: var(--page);
  border: 1px solid var(--line);
  border-radius: 10px;
}

@media (max-width: 900px) {
  .course-header {
    grid-template-columns: 1fr;
    gap: 20px;
  }

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

  .course-nav {
    position: static;
    display: grid;
    grid-template-columns: 1fr auto;
    gap: 10px;
    align-items: end;
  }

  .mobile-day-label,
  .mobile-day-select {
    display: block;
  }

  .mobile-day-label {
    grid-column: 1 / -1;
    color: var(--muted);
    font-size: 0.84rem;
  }

  .mobile-day-select {
    width: 100%;
    padding: 8px 12px;
    color: var(--text);
    background: var(--surface);
    border: 1px solid var(--line);
    border-radius: 10px;
  }

  .week-list {
    display: none;
  }

  .text-button {
    margin: 0;
  }
}

@media (max-width: 680px) {
  .course-shell {
    width: min(100% - 20px, 1180px);
    padding-top: 24px;
  }

  .lesson-card {
    padding: 22px 17px;
    border-radius: 16px;
  }

  .lesson-heading,
  .timer-panel {
    grid-template-columns: 1fr;
  }

  .lesson-heading .complete-button {
    width: 100%;
  }

  .timer-panel {
    gap: 10px;
  }

  .timer-actions {
    display: grid;
    grid-template-columns: 1fr 1fr;
  }

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

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

  .day-position {
    grid-column: 1 / -1;
    grid-row: 1;
  }

  .lesson-pager button:first-of-type {
    grid-column: 1;
  }

  .lesson-pager button:last-of-type {
    grid-column: 2;
  }
}

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

  .progress-fill {
    transition: none;
  }
}