:root {
  --color-bg: #f2f2f2;
  --color-surface: #ffffff;
  --color-primary: #1fa8cc;
  --color-primary-dark: #157b96;
  --color-primary-tint: #e6f6fb;
  --color-text: #1a1a1a;
  --color-muted: #6b6b6b;
  --color-border: #dcdcdc;
  --color-success: #1c9e6e;
  --color-success-tint: #e4f7ef;
  --color-danger: #d1453b;
  --color-locked: #9a9a9a;
  --color-warning: #e0a72c;
  --color-warning-dark: #b8871f;
  --color-warning-text: #4d3a0a;
  --color-loilo: #1c9e6e;
  --color-loilo-dark: #167a56;
  --radius: 12px;
  --shadow: 0 2px 10px rgba(0, 0, 0, 0.06);
  font-size: 15px;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: "UD デジタル 教科書体 N-R", "UD Digital Kyokasho N-R", "BIZ UDPGothic", "Hiragino Sans", "Yu Gothic", "Meiryo", system-ui, sans-serif;
  background: var(--color-bg);
  color: var(--color-text);
  line-height: 1.5;
  -webkit-user-select: none;
  user-select: none;
}

input,
textarea,
.allow-copy {
  -webkit-user-select: text;
  user-select: text;
}

.page {
  max-width: 720px;
  margin: 0 auto;
  padding: 16px 20px 32px;
}

.site-nav {
  position: sticky;
  top: 0;
  z-index: 20;
  background: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
  padding: 10px 20px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 10px;
}

.site-nav-logo {
  font-weight: 700;
  font-size: 0.95rem;
  color: var(--color-primary-dark);
  text-decoration: none;
  white-space: nowrap;
}

.site-nav-links {
  display: flex;
  align-items: center;
  gap: 16px;
  flex-wrap: wrap;
}

.site-nav-links a {
  color: var(--color-text);
  text-decoration: none;
  font-size: 0.82rem;
  font-weight: 600;
  white-space: nowrap;
}

.site-nav-links a:hover {
  color: var(--color-primary);
}

.site-nav-links a.site-nav-loilo {
  background: var(--color-loilo);
  color: #fff;
  padding: 5px 12px;
  border-radius: 999px;
}

.site-nav-links a.site-nav-loilo:hover {
  background: var(--color-loilo-dark);
  color: #fff;
}

header.site-header {
  padding: 8px 20px;
  text-align: center;
}

header.site-header h1 {
  font-size: 1.2rem;
  margin: 0;
  color: var(--color-primary-dark);
}

header.site-header p {
  margin: 2px 0 0;
  color: var(--color-muted);
  font-size: 0.85rem;
}

.student-bar {
  display: flex;
  justify-content: flex-end;
  align-items: center;
  gap: 8px;
  max-width: 720px;
  margin: 0 auto;
  padding: 8px 20px 0;
  font-size: 0.85rem;
  color: var(--color-muted);
}

.student-bar button {
  background: none;
  border: none;
  color: var(--color-primary);
  cursor: pointer;
  font-size: 0.85rem;
  text-decoration: underline;
  padding: 0;
}

.chapter-list {
  display: flex;
  flex-direction: column;
  gap: 8px;
  margin-top: 12px;
}

.chapter-card {
  background: var(--color-surface);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 11px 16px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 16px;
  border: 1px solid var(--color-border);
}

.chapter-card.locked {
  opacity: 0.6;
}

.chapter-card > div:last-child {
  flex-shrink: 0;
  text-align: center;
}

.chapter-card .chapter-info {
  min-width: 0;
}

.chapter-card .chapter-info h2 {
  font-size: 1rem;
  margin: 0 0 4px;
}

.chapter-card .chapter-info p {
  margin: 0;
  font-size: 0.8rem;
  color: var(--color-muted);
}

.keyword-search {
  display: block;
  width: 100%;
  box-sizing: border-box;
  padding: 8px 14px;
  margin-top: 14px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  font-size: 0.95rem;
  background: var(--color-surface);
  color: var(--color-text);
}

.keyword-group {
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  background: var(--color-surface);
  overflow: hidden;
}

.keyword-group summary {
  cursor: pointer;
  padding: 11px 18px;
  font-weight: 700;
  list-style: none;
  display: flex;
  align-items: center;
  user-select: none;
}

.keyword-group summary::-webkit-details-marker {
  display: none;
}

.keyword-group summary::before {
  content: "▸";
  color: var(--color-muted);
  margin-right: 10px;
  transition: transform 0.15s;
  display: inline-block;
}

.keyword-group[open] summary::before {
  transform: rotate(90deg);
}

.keyword-group-count {
  font-size: 0.8rem;
  color: var(--color-muted);
  font-weight: 400;
  margin-left: 8px;
}

.keyword-group .chapter-list {
  margin-top: 0;
  padding: 0 18px 14px;
}

.keyword-type-heading {
  margin: 4px 0 0;
  font-size: 0.75rem;
  font-weight: 700;
  color: var(--color-primary);
  letter-spacing: 0.03em;
}

.keyword-type-heading:first-child {
  margin-top: 0;
}

.no-results {
  color: var(--color-muted);
  text-align: center;
  padding: 24px;
}

.badge {
  font-size: 0.75rem;
  padding: 2px 8px;
  border-radius: 999px;
  background: var(--color-primary-tint);
  color: var(--color-primary-dark);
  white-space: nowrap;
}

.badge.complete {
  background: var(--color-success-tint);
  color: var(--color-success);
}

.btn {
  display: inline-block;
  border: none;
  border-radius: 8px;
  padding: 10px 18px;
  font-size: 0.9rem;
  font-weight: 600;
  cursor: pointer;
  text-decoration: none;
  text-align: center;
  white-space: nowrap;
  transition: background 0.15s ease;
}

.btn-primary {
  background: var(--color-primary);
  color: #fff;
}

.btn-primary:hover {
  background: var(--color-primary-dark);
}

.btn-secondary {
  background: var(--color-surface);
  color: var(--color-primary);
  border: 1px solid var(--color-primary);
}

.btn-danger {
  background: var(--color-danger);
  color: #fff;
}

.btn-danger:hover {
  background: #b23a31;
}

.btn-disabled {
  background: var(--color-locked);
  color: #fff;
  cursor: not-allowed;
  pointer-events: none;
}

.btn-warning {
  background: var(--color-warning);
  color: var(--color-warning-text);
}

.btn-warning:hover {
  background: var(--color-warning-dark);
}

.btn-muted {
  background: var(--color-locked);
  color: #fff;
}

.btn-muted:hover {
  background: #7d7d7d;
}

.btn-loilo {
  background: var(--color-loilo);
  color: #fff;
}

.btn-loilo:hover {
  background: var(--color-loilo-dark);
}

.card {
  background: var(--color-surface);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  border: 1px solid var(--color-border);
  padding: 18px 20px;
}

form.login-form {
  display: flex;
  flex-direction: column;
  gap: 14px;
}

form.login-form label {
  font-size: 0.9rem;
  font-weight: 600;
}

form.login-form input {
  font-size: 1rem;
  padding: 10px 12px;
  border-radius: 8px;
  border: 1px solid var(--color-border);
}

.error-text {
  color: var(--color-danger);
  font-size: 0.85rem;
  min-height: 1.2em;
}

.quiz-progress {
  font-size: 0.85rem;
  color: var(--color-muted);
  margin-bottom: 6px;
}

.quiz-unit {
  display: inline-block;
  font-size: 0.75rem;
  background: var(--color-primary-tint);
  color: var(--color-primary-dark);
  padding: 2px 10px;
  border-radius: 999px;
  margin-bottom: 10px;
}

.quiz-question {
  font-size: 1.05rem;
  margin: 6px 0 14px;
}

.code-label {
  font-size: 0.78rem;
  color: var(--color-muted);
  margin: 10px 0 4px;
}

.code-block {
  background: #1e1e1e;
  color: #d4d4d4;
  font-family: "Consolas", "Menlo", "Courier New", monospace;
  font-size: 0.85rem;
  line-height: 1.5;
  padding: 12px 14px;
  border-radius: 8px;
  overflow-x: auto;
  white-space: pre;
  margin: 0 0 12px;
}

.quiz-choices {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.quiz-choice {
  display: block;
  width: 100%;
  text-align: left;
  padding: 10px 14px;
  border: 1px solid var(--color-border);
  border-radius: 8px;
  background: var(--color-surface);
  cursor: pointer;
  font-size: 0.95rem;
  /* コード片の選択肢はインデントの有無が正誤を分けることがあるため、先頭の空白を潰さず表示する */
  white-space: pre-wrap;
}

.quiz-choice:hover {
  border-color: var(--color-primary);
}

.quiz-choice.selected {
  border-color: var(--color-primary);
  background: var(--color-primary-tint);
}

.quiz-choice.correct {
  border-color: var(--color-success);
  background: var(--color-success-tint);
}

.quiz-choice.incorrect {
  border-color: var(--color-danger);
  background: #fbe9e8;
}

.quiz-choice:disabled {
  cursor: default;
}

.quiz-feedback {
  margin-top: 12px;
  font-size: 0.9rem;
  color: var(--color-muted);
}

.quiz-actions {
  margin-top: 14px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 10px;
}

.result-summary {
  text-align: center;
}

.result-score {
  font-size: 2.4rem;
  font-weight: 700;
  color: var(--color-success);
  margin: 10px 0;
}

.result-actions {
  margin-top: 16px;
  display: flex;
  gap: 12px;
  justify-content: center;
  flex-wrap: wrap;
}

.certificate {
  border: 6px solid var(--color-primary);
  border-radius: var(--radius);
  padding: 26px 24px;
  text-align: center;
  background: #fff;
}

.certificate h2 {
  color: var(--color-primary-dark);
  margin-top: 0;
}

.certificate .cert-name {
  margin: 14px 0;
}

.certificate .cert-name div:first-child {
  font-size: 1.1rem;
  color: var(--color-muted);
  font-weight: 600;
}

.certificate .cert-name div:last-child {
  font-size: 1.8rem;
  font-weight: 700;
  margin-top: 4px;
}

.certificate .cert-meta {
  color: var(--color-muted);
  font-size: 0.9rem;
}

.center {
  text-align: center;
}

.mt-24 {
  margin-top: 14px;
}

.last-studied {
  margin: 4px 0 0;
  font-size: 0.72rem;
  color: var(--color-muted);
  text-align: center;
}

/* ---- 終了証のランク配色(出題数: 5=青/10=緑/15=銅/20=銀/30=金) ---- */
.certificate .cert-tier-label {
  display: inline-block;
  margin: 0 auto 4px;
  padding: 2px 16px;
  border-radius: 999px;
  font-size: 0.85rem;
  font-weight: 700;
  color: #fff;
  background: var(--color-muted);
}

.certificate.cert-tier-blue { border-color: #2f6fd0; background: #f3f7fd; }
.certificate.cert-tier-blue h2 { color: #2456a8; }
.certificate.cert-tier-blue .cert-tier-label { background: #2f6fd0; }

.certificate.cert-tier-green { border-color: #1c9e6e; background: #eefaf4; }
.certificate.cert-tier-green h2 { color: #157a54; }
.certificate.cert-tier-green .cert-tier-label { background: #1c9e6e; }

.certificate.cert-tier-bronze { border-color: #b0713a; background: #faf1e8; }
.certificate.cert-tier-bronze h2 { color: #8f5626; }
.certificate.cert-tier-bronze .cert-tier-label { background: #b0713a; }

.certificate.cert-tier-silver { border-color: #9aa2ad; background: #f4f6f8; }
.certificate.cert-tier-silver h2 { color: #6d7683; }
.certificate.cert-tier-silver .cert-tier-label { background: #9aa2ad; }

.certificate.cert-tier-gold { border-color: #d0a321; background: #fdf7e3; }
.certificate.cert-tier-gold h2 { color: #a67c00; }
.certificate.cert-tier-gold .cert-tier-label { background: #d0a321; }

/* ---- 出題数選択画面 ---- */
.count-select-heading {
  margin: 0 0 8px;
  text-align: center;
}

.count-select-note {
  text-align: center;
  color: var(--color-muted);
  font-size: 0.9rem;
  margin: 0 0 20px;
}

.count-select-options {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  justify-content: center;
}

.count-select-btn {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 2px;
  min-width: 96px;
  padding: 14px 18px;
  border-radius: var(--radius);
  border: 2px solid var(--color-border);
  background: var(--color-surface);
  cursor: pointer;
  font-family: inherit;
  font-size: 1rem;
  transition: transform 0.1s ease;
}

.count-select-btn:hover {
  transform: translateY(-2px);
}

.count-select-num {
  font-size: 1.3rem;
  font-weight: 700;
}

.count-select-tier {
  font-size: 0.78rem;
  font-weight: 700;
}

.count-select-btn.count-tier-blue { border-color: #2f6fd0; }
.count-select-btn.count-tier-blue .count-select-tier { color: #2f6fd0; }
.count-select-btn.count-tier-green { border-color: #1c9e6e; }
.count-select-btn.count-tier-green .count-select-tier { color: #1c9e6e; }
.count-select-btn.count-tier-bronze { border-color: #b0713a; }
.count-select-btn.count-tier-bronze .count-select-tier { color: #b0713a; }
.count-select-btn.count-tier-silver { border-color: #9aa2ad; }
.count-select-btn.count-tier-silver .count-select-tier { color: #6d7683; }
.count-select-btn.count-tier-gold { border-color: #d0a321; }
.count-select-btn.count-tier-gold .count-select-tier { color: #a67c00; }

.cert-history {
  margin-top: 16px;
  font-size: 0.8rem;
  color: var(--color-muted);
}

.cert-history .cert-history-dates {
  color: var(--color-text);
}

.cert-restored-note {
  max-width: 480px;
  margin: 16px auto 0;
  padding: 10px 14px;
  border-radius: var(--radius);
  background: var(--color-warning);
  color: var(--color-warning-text);
  font-size: 0.85rem;
  line-height: 1.6;
  text-align: center;
}

.site-footer {
  max-width: 720px;
  margin: 16px auto 0;
  padding: 8px 20px 14px;
  text-align: center;
  font-size: 0.72rem;
  color: var(--color-muted);
  border-top: 1px solid var(--color-border);
}

.site-footer a {
  color: var(--color-primary-dark);
}