:root {
  --bg: #ffffff;
  --bg-card: #f8fafc;
  --bg-code: #1e293b;
  --text: #1e3a5f;
  --text-muted: #64748b;
  --accent: #2563eb;
  --accent-hover: #1d4ed8;
  --accent-light: #dbeafe;
  --success: #16a34a;
  --success-bg: #dcfce7;
  --error: #dc2626;
  --error-bg: #fee2e2;
  --warning-bg: #fef3c7;
  --warning-text: #92400e;
  --border: #cbd5e1;
  --header-bg: #1e3a5f;
  --header-text: #ffffff;
  --btn-radius: 0.5rem;
  --shadow: 0 4px 6px -1px rgb(0 0 0 / 0.1);
  --safe-top: env(safe-area-inset-top, 0px);
  --safe-right: env(safe-area-inset-right, 0px);
  --safe-left: env(safe-area-inset-left, 0px);
  --header-base-height: 3.25rem;
  --header-total-height: calc(var(--header-base-height) + var(--safe-top));
}

[data-theme="cool"] {
  --bg: #0a0a0f;
  --bg-card: #14141f;
  --bg-code: #0d1117;
  --text: #e0f2fe;
  --text-muted: #67e8f9;
  --accent: #00ff88;
  --accent-hover: #00cc6a;
  --accent-light: #064e3b;
  --success: #00ff88;
  --success-bg: #064e3b;
  --error: #ff4466;
  --error-bg: #450a0a;
  --warning-bg: #1a1a2e;
  --warning-text: #00ff88;
  --border: #2d2d44;
  --header-bg: #0d1117;
  --header-text: #00ff88;
  --btn-radius: 0.375rem;
  --shadow: 0 0 20px rgb(0 255 136 / 0.15);
}

[data-theme="pop"] {
  --bg: #fff8f0;
  --bg-card: #ffffff;
  --bg-code: #4a3728;
  --text: #5c4033;
  --text-muted: #8b6914;
  --accent: #ff8c42;
  --accent-hover: #e6732f;
  --accent-light: #ffe4cc;
  --success: #7cb342;
  --success-bg: #e8f5e9;
  --error: #e53935;
  --error-bg: #ffebee;
  --warning-bg: #fff9c4;
  --warning-text: #f57f17;
  --border: #ffd699;
  --header-bg: #ff8c42;
  --header-text: #ffffff;
  --btn-radius: 1rem;
  --shadow: 0 4px 12px rgb(255 140 66 / 0.25);
}

* { box-sizing: border-box; }

body {
  background: var(--bg);
  color: var(--text);
  font-family: "Hiragino Sans", "Hiragino Kaku Gothic ProN", "Noto Sans JP", sans-serif;
  min-height: 100dvh;
  overflow-x: hidden;
  transition: background 0.3s, color 0.3s;
}

.themed-header {
  position: fixed !important;
  top: 0;
  left: 0;
  right: 0;
  z-index: 50;
  background: var(--header-bg);
  color: var(--header-text);
  min-height: var(--header-total-height);
  padding-top: calc(0.75rem + var(--safe-top));
  padding-right: calc(1rem + var(--safe-right));
  padding-bottom: 0.75rem;
  padding-left: calc(1rem + var(--safe-left));
}

.themed-header > * {
  min-width: 0;
}

.header-brand {
  flex: 1 1 auto;
}

.app-title {
  min-width: 0;
  font-size: 1.05rem;
  font-weight: 800;
  letter-spacing: 0.02em;
}

.header-back-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  flex: 0 0 auto;
  position: relative;
  width: 2.4rem;
  height: 2.4rem;
  border: 1px solid rgba(255,255,255,0.35);
  border-radius: 999px;
  background: rgba(255,255,255,0.12);
  color: var(--header-text);
  font-size: 0;
  text-decoration: none;
  transition: background 0.2s, transform 0.1s;
}

.header-back-btn::before {
  content: "";
  width: 0.58rem;
  height: 0.58rem;
  border-left: 3px solid currentColor;
  border-bottom: 3px solid currentColor;
  transform: rotate(45deg);
  margin-left: 0.18rem;
}

.header-back-btn:active {
  transform: scale(0.94);
}

.header-back-btn:hover {
  background: rgba(255,255,255,0.22);
}

.themed-header + main {
  padding-top: 0.75rem !important;
}

.themed-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--btn-radius);
  box-shadow: var(--shadow);
}

.learning-status-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin: 0 0 0.75rem;
}

.learning-status-btn {
  flex: 1 1 8rem;
  min-height: 2.75rem;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.7rem 0.9rem;
  border: 2px solid var(--accent);
  border-radius: var(--btn-radius);
  background: var(--accent-light);
  color: var(--accent);
  font-size: 0.9rem;
  font-weight: 800;
  line-height: 1.2;
  text-align: center;
}

.learning-status-btn:hover {
  filter: brightness(0.98);
}

.learning-status-btn:active {
  transform: scale(0.98);
}

.learning-status-modal {
  position: fixed;
  inset: 0;
  z-index: 90;
  display: grid;
  place-items: center;
  padding: 1rem;
}

.learning-status-backdrop {
  position: absolute;
  inset: 0;
  background: rgba(3, 7, 18, 0.68);
  border: 0;
}

.learning-status-panel {
  position: relative;
  width: 100%;
  max-width: 28rem;
  border: 1px solid var(--accent);
  border-radius: 1.2rem;
  background: var(--bg-card);
  box-shadow: 0 24px 60px rgba(0, 0, 0, 0.38);
  color: var(--text);
  padding: 1rem;
}

.learning-status-panel-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  margin-bottom: 0.9rem;
}

.learning-status-kicker {
  color: var(--accent);
  font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", monospace;
  font-size: 0.68rem;
  font-weight: 900;
  letter-spacing: 0.08em;
}

.learning-status-close {
  display: grid;
  place-items: center;
  width: 2.15rem;
  height: 2.15rem;
  border: 1px solid var(--border);
  border-radius: 999px;
  background: var(--bg);
  color: var(--text);
  font-size: 1.25rem;
  font-weight: 800;
  line-height: 1;
}

.learning-status-section {
  border: 1px solid var(--border);
  border-radius: 0.95rem;
  background: var(--bg);
  padding: 0.95rem;
}

.learning-status-section + .learning-status-section {
  margin-top: 0.75rem;
}

.learning-status-actions.hidden,
.learning-status-modal.hidden,
.learning-status-section.hidden,
.learning-status-btn.hidden {
  display: none;
}

.themed-btn-primary {
  background: var(--accent);
  color: #fff;
  border-radius: var(--btn-radius);
  transition: background 0.2s, transform 0.1s;
}
[data-theme="cool"] .themed-btn-primary { color: #0a0a0f; }
.themed-btn-primary:active { transform: scale(0.97); }
.themed-btn-primary:hover { background: var(--accent-hover); }

.themed-btn-secondary {
  background: var(--bg-card);
  color: var(--text);
  border: 2px solid var(--border);
  border-radius: var(--btn-radius);
  transition: all 0.2s;
}
.themed-btn-secondary.selected {
  background: var(--accent-light);
  border-color: var(--accent);
  color: var(--accent);
  font-weight: 700;
}
[data-theme="cool"] .themed-btn-secondary.selected { color: var(--accent); }

.themed-text-muted { color: var(--text-muted); }

.code-block {
  background: var(--bg-code);
  color: #e2e8f0;
  font-family: "Consolas", "Monaco", "Courier New", monospace;
  display: block;
  max-width: 100%;
  font-size: 0.85rem;
  line-height: 1.6;
  padding: 1rem;
  border-radius: var(--btn-radius);
  overflow-x: auto;
  white-space: pre;
  -webkit-overflow-scrolling: touch;
}
[data-theme="cool"] .code-block { color: #00ff88; border: 1px solid #2d2d44; }
[data-theme="pop"] .code-block { color: #fff8f0; }

.warning-box {
  background: var(--warning-bg);
  color: var(--warning-text);
  border-radius: var(--btn-radius);
  font-size: 0.8rem;
  padding: 0.6rem 0.75rem;
}

.choice-btn {
  display: flex;
  align-items: flex-start;
  gap: 0.55rem;
  min-height: 3.25rem;
  padding: 0.875rem 1rem;
  font-size: 1rem;
  font-weight: 600;
  border-radius: var(--btn-radius);
  border: 2px solid var(--border);
  background: var(--bg-card);
  color: var(--text);
  transition: all 0.15s;
  word-break: break-word;
  text-align: left;
}
.choice-label {
  flex: 0 0 1.65rem;
  font-weight: 800;
  text-align: right;
}
.choice-text {
  min-width: 0;
  white-space: pre-wrap;
}
.choice-btn-code {
  font-family: "Consolas", "Monaco", "Courier New", monospace;
  font-size: 0.82rem;
  font-weight: 500;
  line-height: 1.55;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
}
.choice-btn-code .choice-text {
  flex: 1 0 max-content;
  white-space: pre;
  word-break: normal;
  overflow-wrap: normal;
}
.choice-btn:active:not(:disabled) { transform: scale(0.98); }
.choice-btn:disabled { cursor: default; }
.choice-btn.correct {
  background: var(--success-bg) !important;
  border-color: var(--success) !important;
  color: var(--success) !important;
}
.choice-btn.wrong {
  background: var(--error-bg) !important;
  border-color: var(--error) !important;
  color: var(--error) !important;
}

.feedback-ok {
  background: var(--success-bg);
  color: var(--success);
  border: 2px solid var(--success);
  border-radius: var(--btn-radius);
  animation: popIn 0.3s ease;
}
.feedback-ng {
  background: var(--error-bg);
  color: var(--error);
  border: 2px solid var(--error);
  border-radius: var(--btn-radius);
  animation: shake 0.4s ease;
}

@keyframes popIn {
  0% { transform: scale(0.8); opacity: 0; }
  60% { transform: scale(1.05); }
  100% { transform: scale(1); opacity: 1; }
}
@keyframes shake {
  0%, 100% { transform: translateX(0); }
  20% { transform: translateX(-6px); }
  40% { transform: translateX(6px); }
  60% { transform: translateX(-4px); }
  80% { transform: translateX(4px); }
}

details.explanation {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--btn-radius);
  overflow: hidden;
}
details.explanation summary {
  padding: 0.875rem 1rem;
  cursor: pointer;
  font-weight: 700;
  color: var(--accent);
  list-style: none;
  user-select: none;
}
details.explanation summary::-webkit-details-marker { display: none; }
details.explanation .explanation-body {
  padding: 1rem 1.15rem 1.15rem;
  font-size: 0.95rem;
  line-height: 1.9;
  color: var(--text);
  border-top: 1px solid var(--border);
  min-height: 5.5rem;
}

.quiz-toolbar {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  margin: 0 0 0.65rem;
}

.header-quiz-actions {
  display: none;
  flex: 0 0 auto;
  gap: 0.4rem;
  margin-left: auto;
}

.header-quiz-action-btn {
  min-height: 2rem;
  min-width: 0;
  padding: 0.35rem 0.75rem;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: var(--bg-card);
  color: var(--text);
  font-size: 0.78rem;
  font-weight: 700;
  white-space: nowrap;
}

.header-quiz-action-btn:hover {
  border-color: var(--accent);
  color: var(--accent);
}

.header-stats {
  display: none;
  align-items: center;
  min-height: 2rem;
  padding: 0.3rem 0.7rem;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: var(--bg-card);
  color: var(--text-muted);
  font-size: 0.78rem;
  font-weight: 800;
  white-space: nowrap;
}

body.is-quiz-screen .header-stats.has-score {
  display: inline-flex;
}

body.is-quiz-screen .header-quiz-actions {
  display: flex;
}

@media (max-width: 767px) {
  :root {
    --header-base-height: 3.75rem;
  }

  .themed-header {
    gap: 0.5rem;
    padding-top: calc(1.15rem + var(--safe-top));
    padding-bottom: 0.65rem;
  }

  .themed-header > .flex:first-child {
    flex: 1 1 auto;
    max-width: 58vw;
  }

  .themed-header > .header-brand:first-child {
    max-width: none;
    min-width: 0;
  }

  body.is-quiz-screen .themed-header > .flex:first-child {
    max-width: 36vw;
  }

  .app-title {
    font-size: 0.92rem;
    letter-spacing: 0.01em;
  }

  .header-back-btn {
    width: 2.25rem;
    height: 2.25rem;
  }
}

.pattern-badge {
  font-size: 0.7rem;
  padding: 0.2rem 0.5rem;
  border-radius: 9999px;
  background: var(--accent-light);
  color: var(--accent);
  font-weight: 700;
}

.progress-bar {
  height: 4px;
  background: var(--border);
  border-radius: 2px;
  overflow: hidden;
}
.progress-fill {
  height: 100%;
  background: var(--accent);
  transition: width 0.3s;
}

body.is-quiz-screen .quiz-progress {
  position: relative;
  top: auto;
  left: auto;
  right: auto;
  z-index: auto;
  margin: 0 0 0.65rem;
  border-radius: 2px;
}

body.is-quiz-screen #screen-quiz {
  padding-top: 0;
}

.quiz-prompt {
  color: var(--text);
  line-height: 1.7;
}

.theme-option-card {
  display: flex;
  align-items: flex-start;
  gap: 0.9rem;
  width: 100%;
  padding: 1rem;
  text-align: left;
  transition: transform 0.15s, border-color 0.15s;
}

.theme-option-card:active {
  transform: scale(0.98);
}

.theme-option-card.selected {
  border-color: var(--accent);
  outline: 3px solid var(--accent-light);
}

.theme-option-icon {
  display: grid;
  place-items: center;
  width: 2.5rem;
  height: 2.5rem;
  border-radius: var(--btn-radius);
  background: var(--accent-light);
  color: var(--accent);
  font-size: 1.3rem;
  flex: 0 0 auto;
}

.theme-option-body {
  display: grid;
  gap: 0.25rem;
}

.theme-option-title {
  color: var(--text);
  font-size: 1rem;
  font-weight: 800;
}

.theme-option-desc {
  color: var(--text-muted);
  font-size: 0.85rem;
  line-height: 1.6;
}

.notation-nav {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 0.5rem;
  max-width: 100%;
  overflow: hidden;
}

.notation-nav a {
  border: 1px solid var(--border);
  border-radius: var(--btn-radius);
  color: var(--text);
  font-size: 0.8rem;
  font-weight: 700;
  padding: 0.55rem 0.65rem;
  text-decoration: none;
}

.notation-nav a:active {
  transform: scale(0.98);
}

.notation-grid {
  display: grid;
  gap: 1rem;
  max-width: 100%;
  overflow: hidden;
}

.notation-card {
  min-width: 0;
  max-width: 100%;
  padding: 1rem;
  scroll-margin-top: 4.5rem;
}

.notation-card .code-block {
  white-space: pre-wrap;
  overflow-wrap: anywhere;
}

.notation-card h2 {
  color: var(--text);
  font-size: 1.05rem;
  font-weight: 800;
  margin-bottom: 0.45rem;
}

.notation-card p {
  color: var(--text);
  font-size: 0.9rem;
  line-height: 1.7;
  margin-bottom: 0.75rem;
}

.notation-run-btn {
  margin-top: 0.75rem;
  padding: 0.65rem 0.9rem;
  font-size: 0.9rem;
  font-weight: 800;
}

.notation-output {
  display: none;
  margin-top: 0.75rem;
  border: 1px solid var(--border);
  border-radius: var(--btn-radius);
  background: var(--accent-light);
  color: var(--text);
  font-family: "Consolas", "Monaco", "Courier New", monospace;
  font-size: 0.82rem;
  line-height: 1.7;
  padding: 0.75rem;
  white-space: pre-wrap;
  overflow-x: auto;
}

.notation-output.show {
  display: block;
}

.algorithm-index-card {
  display: grid;
  align-content: start;
  gap: 0.7rem;
}

.algorithm-index-head {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.algorithm-index-num {
  display: grid;
  place-items: center;
  flex: 0 0 auto;
  width: 1.7rem;
  height: 1.7rem;
  border-radius: 999px;
  background: var(--accent);
  color: #fff;
  font-family: "Consolas", "Monaco", "Courier New", monospace;
  font-size: 0.85rem;
  font-weight: 900;
}

[data-theme="cool"] .algorithm-index-num {
  color: #0a0a0f;
}

.algorithm-index-title {
  min-width: 0;
  margin: 0;
  color: var(--text);
  font-size: 1.02rem;
  font-weight: 800;
  line-height: 1.4;
}

.algorithm-index-head .pattern-badge {
  flex: 0 0 auto;
  margin-left: auto;
  white-space: nowrap;
}

.algorithm-index-summary {
  margin: 0;
  color: var(--text);
  font-size: 0.87rem;
  line-height: 1.85;
}

.algorithm-sim-link {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.4rem;
  border: 2px solid var(--accent);
  border-radius: var(--btn-radius);
  background: var(--accent-light);
  color: var(--accent);
  font-size: 0.85rem;
  font-weight: 800;
  padding: 0.7rem 0.85rem;
  text-align: center;
  text-decoration: none;
  transition: background 0.18s ease, transform 0.1s ease;
}

.algorithm-sim-link::after {
  content: "›";
  font-size: 1.05rem;
  font-weight: 900;
}

.algorithm-sim-link:hover {
  background: var(--accent);
  color: #fff;
}

[data-theme="cool"] .algorithm-sim-link:hover {
  color: #0a0a0f;
}

.algorithm-sim-link:active {
  transform: scale(0.98);
}

/* まだ詳細ページがないアルゴリズム。リンクではなく状態表示にする。 */
.algorithm-sim-link.is-pending {
  border-style: dashed;
  border-color: var(--border);
  background: transparent;
  color: var(--text-muted);
  cursor: default;
}

.algorithm-sim-link.is-pending::after {
  content: none;
}

.algorithm-sim-link.is-pending:hover {
  background: transparent;
  color: var(--text-muted);
}

.site-footer {
  width: 100%;
  margin: 2rem 0 0;
  padding: 1.6rem 1rem calc(1.6rem + var(--safe-bottom, 0px));
  border-top: 1px solid rgba(255, 255, 255, 0.12);
  background: linear-gradient(180deg, #111827 0%, #030712 100%);
  box-shadow: 0 -10px 28px rgba(0, 0, 0, 0.18);
  color: rgba(255, 255, 255, 0.72);
  text-align: center;
}

.site-footer-share {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  margin-bottom: 1rem;
}

.site-footer-share-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border: 1px solid transparent;
  border-radius: 0.45rem;
  box-shadow: 0 6px 14px rgba(0, 0, 0, 0.22);
  color: #fff;
  font-size: 0.74rem;
  font-weight: 800;
  line-height: 1;
  width: 6.4rem;
  padding: 0.58rem 0.7rem;
  text-decoration: none;
  transition: transform 0.15s ease, filter 0.15s ease, box-shadow 0.15s ease;
}

.site-footer-share-btn:hover {
  color: #fff;
  filter: brightness(1.08);
  transform: translateY(-1px);
  box-shadow: 0 8px 18px rgba(0, 0, 0, 0.28);
}

.share-x {
  background: #111;
  border-color: rgba(255, 255, 255, 0.3);
}

.share-line {
  background: #06c755;
}

.share-facebook {
  background: #1877f2;
}

.site-footer-links {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 0.55rem 1.25rem;
  max-width: 25rem;
  margin-left: auto;
  margin-right: auto;
  margin-bottom: 0.75rem;
}

.site-footer-links a {
  color: rgba(255, 255, 255, 0.78);
  font-size: 0.78rem;
  font-weight: 700;
  text-decoration: none;
}

.site-footer-links a:hover {
  color: #fff;
}

.site-footer-copy {
  color: rgba(255, 255, 255, 0.52);
  font-size: 0.72rem;
}

body.is-quiz-screen .site-footer {
  display: none;
}

.top-hero {
  text-align: center;
  margin-bottom: 1.5rem;
}

.top-layout {
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}

.top-action-panel,
.top-info-panel {
  min-width: 0;
}

.top-guides {
  display: grid;
  gap: 0.5rem;
  margin-top: 0.75rem;
}

@media (min-width: 900px) {
  body:not(.is-quiz-screen) .app-shell {
    max-width: 1120px;
  }

  #screen-top {
    display: grid;
    grid-template-columns: minmax(0, 1.15fr) minmax(19rem, 0.85fr);
    grid-template-areas:
      "hero action"
      "info action";
    align-items: start;
    column-gap: 1.1rem;
    row-gap: 0.85rem;
  }

  .top-hero {
    grid-area: hero;
    margin: 0;
    text-align: left;
  }

  .top-hero h1 {
    font-size: 1.85rem;
    line-height: 1.2;
  }

  .top-hero h1 br {
    display: none;
  }

  .top-hero p {
    font-size: 0.9rem;
  }

  .top-layout {
    display: contents;
  }

  .top-info-panel {
    grid-area: info;
  }

  .top-action-panel {
    --top-action-h: calc(100dvh - var(--it1-header-h, var(--header-total-height)) - 1rem);
    grid-area: action;
    position: sticky;
    top: calc(var(--it1-header-h, var(--header-total-height)) + 0.5rem);
    height: var(--top-action-h);
    max-height: var(--top-action-h);
    display: flex;
    flex-direction: column;
    gap: 0.55rem;
    min-height: 0;
  }

  .top-action-panel > .themed-card {
    margin: 0 !important;
    padding: 0.7rem 0.8rem !important;
    display: flex;
    flex-direction: column;
    min-height: 0;
  }

  .top-action-panel > .themed-card:first-child {
    flex: 1.35 1 0;
  }

  .top-action-panel > .themed-card:not(:first-child) {
    flex: 0 0 auto;
  }

  .top-action-panel > .themed-card h2 {
    margin-bottom: 0.45rem !important;
    font-size: 0.8rem;
    line-height: 1.2;
  }

  .top-action-panel #lang-mode-group {
    flex: 1;
    display: grid;
    grid-template-rows: repeat(3, minmax(0, 1fr));
    gap: 0.4rem;
    min-height: 0;
  }

  .top-action-panel #difficulty-group,
  .top-action-panel #question-count-group {
    gap: 0.4rem;
  }

  .top-action-panel .themed-btn-secondary {
    min-height: 0;
    height: 100%;
    padding: 0.5rem 0.65rem !important;
    font-size: 0.82rem !important;
    line-height: 1.25;
  }

  .top-action-panel .learning-status-actions {
    margin: 0;
    gap: 0.4rem;
    flex: 0 0 auto;
  }

  .top-action-panel .learning-status-btn {
    min-height: 2.35rem;
    padding: 0.45rem 0.65rem;
    font-size: 0.8rem;
  }

  .top-action-panel .top-start-btn {
    margin: 0;
    flex: 0 0 auto;
    padding: 0.8rem 0.85rem !important;
    font-size: 1.05rem !important;
    line-height: 1.2;
  }

  .top-guides {
    margin-top: 0;
    flex: 1.15 1 0;
    gap: 0.4rem;
    grid-template-columns: 1fr;
    grid-template-rows: repeat(4, minmax(0, 1fr));
    min-height: 0;
  }

  .top-guides .themed-btn-secondary {
    display: flex;
    align-items: center;
    justify-content: center;
    height: 100%;
    min-height: 0;
    padding: 0.45rem 0.75rem !important;
    font-size: 0.8rem !important;
    line-height: 1.25;
    white-space: nowrap;
  }

  .top-info-panel .themed-card:first-child {
    margin-top: 0;
  }

  .top-guide-links {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (min-width: 900px) {
  .notation-nav {
    grid-template-columns: repeat(5, minmax(0, 1fr));
  }

  .notation-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    align-items: start;
  }

  .notation-card .code-block {
    max-height: none;
  }
}

@media (min-width: 768px) {
  body.is-quiz-screen #screen-quiz {
    padding-top: 0;
  }
}

@media (min-width: 900px) {
  body.is-quiz-screen .app-shell {
    max-width: 1120px;
  }

  body.is-quiz-screen #screen-quiz {
    padding-top: 0;
  }

  body.is-quiz-screen .quiz-progress {
    position: static;
    margin: 0;
    border-radius: 2px;
  }

  .quiz-desktop-grid {
    display: block;
  }

  .quiz-main-pane,
  .quiz-side-pane {
    min-width: 0;
  }

  .code-block {
    max-height: 34dvh;
    font-size: 0.9rem;
    overflow: auto;
  }

  .choice-btn {
    min-height: 2.9rem;
    padding: 0.7rem 0.85rem;
  }

  .choice-btn-code {
    font-size: 0.78rem;
  }

  details.explanation .explanation-body {
    max-height: 28dvh;
    overflow-y: auto;
  }
}

.admin-label {
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
  color: var(--text-muted);
  font-size: 0.8rem;
  font-weight: 700;
}

.admin-select {
  width: 100%;
  min-height: 2.75rem;
  border: 2px solid var(--border);
  border-radius: var(--btn-radius);
  background: var(--bg-card);
  color: var(--text);
  padding: 0 0.75rem;
  /* 16px 未満だと iOS が入力時に拡大するため下回らせない */
  font-size: 16px;
}

.admin-input,
.admin-textarea {
  width: 100%;
  border: 2px solid var(--border);
  border-radius: var(--btn-radius);
  background: var(--bg-card);
  color: var(--text);
  padding: 0.65rem 0.75rem;
  font-size: 16px;
}

.admin-textarea {
  line-height: 1.6;
  resize: vertical;
}

.admin-textarea-code {
  font-family: "Consolas", "Monaco", "Courier New", monospace;
  font-size: 0.86rem;
  white-space: pre;
}

.admin-editor-modal {
  position: fixed;
  inset: 0;
  z-index: 90;
  display: grid;
  place-items: center;
  padding: 1rem;
}

.admin-editor-backdrop {
  position: absolute;
  inset: 0;
  border: 0;
  background: rgba(3, 7, 18, 0.68);
}

.admin-editor-panel {
  position: relative;
  width: 100%;
  max-width: 46rem;
  max-height: 88dvh;
  overflow-y: auto;
  border: 1px solid var(--border);
  border-radius: 1.1rem;
  background: var(--bg-card);
  box-shadow: 0 24px 60px rgba(0, 0, 0, 0.38);
  color: var(--text);
  padding: 1rem;
}

.admin-editor-close {
  display: grid;
  place-items: center;
  width: 2.15rem;
  height: 2.15rem;
  border: 1px solid var(--border);
  border-radius: 999px;
  background: var(--bg);
  color: var(--text);
  font-size: 1.25rem;
  font-weight: 800;
  line-height: 1;
}

.admin-editor-form {
  display: grid;
  gap: 0.9rem;
}

.admin-editor-validation {
  border: 1px solid var(--error);
  border-radius: var(--btn-radius);
  background: var(--error-bg);
  color: var(--error);
  font-size: 0.85rem;
  font-weight: 700;
  padding: 0.75rem;
}

.admin-editor-modal.hidden {
  display: none;
}

.admin-summary-card {
  padding: 0.75rem;
  text-align: center;
}

.admin-question-card {
  padding: 1rem;
}

.admin-badge {
  display: inline-flex;
  align-items: center;
  border: 1px solid var(--border);
  border-radius: 9999px;
  color: var(--text-muted);
  font-size: 0.7rem;
  font-weight: 700;
  padding: 0.2rem 0.5rem;
}

.admin-prompt {
  color: var(--text);
  font-size: 0.9rem;
  line-height: 1.7;
}

.admin-code {
  font-size: 0.8rem;
  margin-bottom: 0;
}

.admin-details {
  border-top: 1px solid var(--border);
  color: var(--text);
}

.admin-details summary {
  color: var(--accent);
  cursor: pointer;
  font-size: 0.9rem;
  font-weight: 700;
  padding-top: 0.75rem;
  user-select: none;
}

.admin-choice-list {
  display: grid;
  gap: 0.5rem;
  list-style: none;
  padding: 0;
}

.admin-choice-list li {
  display: flex;
  align-items: flex-start;
  gap: 0.5rem;
  border: 1px solid var(--border);
  border-radius: var(--btn-radius);
  font-size: 0.85rem;
  line-height: 1.6;
  padding: 0.6rem 0.7rem;
}

.admin-choice-label {
  flex: 0 0 1.65rem;
  font-weight: 800;
  text-align: right;
}

.admin-choice-text {
  min-width: 0;
  white-space: pre-wrap;
}

.admin-choice-code .admin-choice-text {
  font-family: "Consolas", "Monaco", "Courier New", monospace;
  font-size: 0.8rem;
  line-height: 1.55;
  flex: 1 0 max-content;
  white-space: pre;
  word-break: normal;
  overflow-wrap: normal;
}

.admin-choice-code {
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
}

.admin-choice-correct {
  background: var(--success-bg);
  border-color: var(--success) !important;
  color: var(--success);
}

.admin-explanation {
  background: var(--accent-light);
  border-radius: var(--btn-radius);
  color: var(--text);
  font-size: 0.85rem;
  line-height: 1.7;
  padding: 0.75rem;
}

.hidden { display: none !important; }

/*
 * 本文中のリンク。
 * Tailwind の preflight が a { color: inherit; text-decoration: inherit; } を
 * 当てるため、何も指定しないと本文と見分けがつかなくなる。
 * class の付いていない a だけを対象にして、ボタンやカード型リンク
 * （.themed-btn-secondary、.sim-next-card など）には影響させない。
 */
.themed-card a:not([class]) {
  color: var(--accent);
  font-weight: 700;
  text-decoration: underline;
  text-underline-offset: 0.15em;
  text-decoration-thickness: 1px;
}

.themed-card a:not([class]):hover,
.themed-card a:not([class]):focus-visible {
  opacity: 0.75;
}