:root {
  color-scheme: light;
  --bg: #f6f7f4;
  --panel: #ffffff;
  --panel-soft: #f0f4f2;
  --text: #1f2933;
  --muted: #667085;
  --line: #d7ded9;
  --accent: #0f766e;
  --accent-dark: #115e59;
  --accent-soft: #d9f0ec;
  --warn: #b45309;
  --warn-soft: #fff3d8;
  --bad: #b42318;
  --bad-soft: #fee4e2;
  --good: #087443;
  --good-soft: #dcfae6;
  --focus: #2563eb;
  --shadow: 0 10px 24px rgba(16, 24, 40, 0.08);
  font-family:
    "Microsoft JhengHei",
    "PingFang TC",
    "Noto Sans TC",
    system-ui,
    sans-serif;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  background: var(--bg);
  color: var(--text);
}

button,
select,
input {
  font: inherit;
}

button {
  cursor: pointer;
}

.app-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 18px 24px;
  border-bottom: 1px solid var(--line);
  background: #ffffff;
}

.app-header h1 {
  margin: 0;
  font-size: 22px;
  font-weight: 700;
  letter-spacing: 0;
}

.app-header p {
  margin: 4px 0 0;
  color: var(--muted);
  font-size: 14px;
}

.score-chip {
  min-width: 104px;
  padding: 8px 12px;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: var(--panel-soft);
  color: var(--accent-dark);
  text-align: center;
  font-weight: 700;
}

.app-shell {
  display: grid;
  grid-template-columns: 300px minmax(0, 1fr);
  min-height: calc(100vh - 78px);
}

.control-panel {
  display: flex;
  flex-direction: column;
  gap: 18px;
  padding: 20px;
  border-right: 1px solid var(--line);
  background: #fbfcfb;
}

.field-label {
  display: block;
  margin-bottom: 8px;
  color: #344054;
  font-size: 13px;
  font-weight: 700;
}

select,
input {
  width: 100%;
  min-height: 40px;
  padding: 8px 10px;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: #ffffff;
  color: var(--text);
}

.fixed-note {
  min-height: 40px;
  display: flex;
  align-items: center;
  padding: 8px 10px;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: var(--panel-soft);
  color: var(--accent-dark);
  font-weight: 700;
}

select:focus,
input:focus,
button:focus-visible {
  outline: 2px solid var(--focus);
  outline-offset: 2px;
}

select:disabled {
  cursor: not-allowed;
  background: #eef2f0;
  color: var(--muted);
}

.segmented {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 4px;
  padding: 4px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--panel-soft);
}

.mode-button {
  min-width: 0;
  min-height: 34px;
  border: 0;
  border-radius: 6px;
  background: transparent;
  color: var(--muted);
  font-weight: 700;
  white-space: nowrap;
}

.mode-button.active {
  background: #ffffff;
  color: var(--accent-dark);
  box-shadow: 0 1px 4px rgba(16, 24, 40, 0.12);
}

.exam-settings,
.practice-settings,
.type-settings,
.history-settings {
  display: none;
}

.exam-settings.visible,
.practice-settings.visible,
.type-settings.visible,
.history-settings.visible {
  display: block;
}

.history-count-label {
  margin-top: 12px;
}

.action-stack {
  display: grid;
  gap: 8px;
}

.primary-action,
.secondary-action,
.check-button,
.submit-exam {
  min-height: 40px;
  border-radius: 6px;
  font-weight: 700;
}

.primary-action,
.submit-exam {
  border: 1px solid var(--accent);
  background: var(--accent);
  color: #ffffff;
}

.primary-action:hover,
.submit-exam:hover {
  background: var(--accent-dark);
}

.primary-action:disabled {
  cursor: not-allowed;
  opacity: 0.55;
  background: #657076;
  border-color: #657076;
}

.secondary-action,
.check-button {
  border: 1px solid var(--line);
  background: #ffffff;
  color: #344054;
}

.filter-stats {
  padding-top: 4px;
  color: var(--muted);
  font-size: 13px;
  line-height: 1.7;
}

.quiz-panel {
  min-width: 0;
  padding: 20px 24px 32px;
  background: var(--bg);
}

.toolbar {
  display: grid;
  grid-template-columns: 40px minmax(0, 1fr) 40px;
  align-items: center;
  gap: 10px;
  margin-bottom: 14px;
}

.icon-button {
  width: 40px;
  height: 40px;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: #ffffff;
  color: var(--text);
  font-size: 28px;
  line-height: 1;
}

.icon-button:disabled {
  cursor: not-allowed;
  opacity: 0.45;
}

#unitProgress {
  min-height: 40px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--muted);
  font-size: 14px;
}

.quiz-content {
  display: grid;
  gap: 14px;
}

.empty-state,
.exam-result,
.passage-box,
.question-card {
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--panel);
  box-shadow: var(--shadow);
}

.empty-state {
  padding: 28px;
  color: var(--muted);
  text-align: center;
}

.unit-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  margin-bottom: 10px;
}

.unit-title {
  margin: 0;
  font-size: 18px;
}

.meta-row {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin-top: 8px;
}

.meta-pill {
  padding: 4px 8px;
  border-radius: 999px;
  background: var(--panel-soft);
  color: #475467;
  font-size: 12px;
  font-weight: 700;
}

.passage-box {
  padding: 18px;
}

.passage-title {
  margin: 0 0 10px;
  color: var(--accent-dark);
  font-size: 15px;
}

.passage-text,
.stem {
  white-space: pre-wrap;
  line-height: 1.75;
}

.passage-text {
  max-height: 360px;
  overflow: auto;
  padding-right: 8px;
  color: #344054;
  font-size: 15px;
}

.question-card {
  padding: 18px;
}

.question-topline {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  margin-bottom: 12px;
}

.question-code {
  font-weight: 800;
}

.stem {
  margin-bottom: 14px;
  font-size: 16px;
}

.options {
  display: grid;
  gap: 8px;
}

.option-button {
  display: grid;
  grid-template-columns: 32px minmax(0, 1fr);
  align-items: start;
  gap: 10px;
  width: 100%;
  min-height: 44px;
  padding: 10px 12px;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: #ffffff;
  color: var(--text);
  text-align: left;
}

.option-button:hover {
  border-color: var(--accent);
}

.option-button:disabled {
  cursor: default;
}

.option-button.selected {
  border-color: var(--accent);
  background: var(--accent-soft);
}

.option-button.correct {
  border-color: var(--good);
  background: var(--good-soft);
}

.option-button.wrong {
  border-color: var(--bad);
  background: var(--bad-soft);
}

.option-key {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 26px;
  height: 26px;
  border: 1px solid currentColor;
  border-radius: 6px;
  font-size: 13px;
  font-weight: 800;
}

.option-text {
  min-width: 0;
  line-height: 1.6;
  overflow-wrap: anywhere;
}

.question-actions {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px;
  margin-top: 12px;
}

.check-button:disabled {
  cursor: not-allowed;
  opacity: 0.5;
}

.feedback {
  margin-top: 12px;
  padding: 12px;
  border-radius: 6px;
  line-height: 1.7;
}

.feedback.good {
  border: 1px solid #a6f4c5;
  background: var(--good-soft);
  color: var(--good);
}

.feedback.bad {
  border: 1px solid #fecdca;
  background: var(--bad-soft);
  color: var(--bad);
}

.feedback.neutral {
  border: 1px solid #fedf89;
  background: var(--warn-soft);
  color: var(--warn);
}

.explanation {
  margin-top: 8px;
  color: #344054;
}

.option-analysis {
  margin-top: 12px;
  padding-top: 12px;
  border-top: 1px solid rgba(102, 112, 133, 0.25);
  color: #344054;
}

.option-analysis h3 {
  margin: 0 0 8px;
  font-size: 15px;
  color: #1f2933;
}

.option-analysis ul {
  display: grid;
  gap: 8px;
  padding: 0;
  margin: 0;
  list-style: none;
}

.analysis-item {
  display: grid;
  grid-template-columns: 30px minmax(0, 1fr);
  gap: 10px;
  padding: 10px;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: #ffffff;
}

.analysis-item.answer {
  border-color: #8bd5ad;
  background: #f2fbf6;
}

.analysis-key {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 26px;
  height: 26px;
  border: 1px solid currentColor;
  border-radius: 6px;
  color: var(--accent-dark);
  font-size: 13px;
  font-weight: 800;
}

.analysis-item strong {
  display: block;
  margin-bottom: 4px;
}

.analysis-item p {
  margin: 0;
  line-height: 1.65;
}

.exam-result {
  padding: 16px;
  border-color: #a7d7cf;
  background: #f3fbf9;
}

.exam-result h2 {
  margin: 0 0 8px;
  font-size: 20px;
}

.submit-row {
  display: flex;
  justify-content: flex-end;
  margin-top: 8px;
}

@media (max-width: 860px) {
  .app-header {
    align-items: flex-start;
    flex-direction: column;
  }

  .app-shell {
    grid-template-columns: 1fr;
  }

  .control-panel {
    border-right: 0;
    border-bottom: 1px solid var(--line);
  }

  .quiz-panel {
    padding: 16px;
  }
}

/* 密碼關卡 overlay */
#gate {
  position: fixed;
  inset: 0;
  z-index: 1000;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--bg);
  padding: 20px;
}
#gate .gate-card {
  width: 100%;
  max-width: 360px;
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 12px;
  box-shadow: var(--shadow);
  padding: 24px;
}
#gate h1 {
  margin: 0 0 6px;
  font-size: 20px;
}
#gate p {
  margin: 0 0 16px;
  color: var(--muted);
  font-size: 14px;
  line-height: 1.6;
}
#gate .gate-row {
  display: flex;
  gap: 8px;
}
#gate input {
  flex: 1;
}
#gate .gate-btn {
  min-height: 40px;
  padding: 0 16px;
  border: 1px solid var(--accent);
  border-radius: 6px;
  background: var(--accent);
  color: #fff;
  font-weight: 700;
  white-space: nowrap;
}
#gate .gate-btn:disabled {
  opacity: 0.6;
  cursor: default;
}
#gate .gate-error {
  margin-top: 10px;
  color: var(--bad);
  font-size: 13px;
  min-height: 18px;
}
#gate .gate-show {
  display: flex;
  align-items: center;
  gap: 6px;
  margin-top: 10px;
  color: var(--muted);
  font-size: 13px;
  cursor: pointer;
}
#gate .gate-show input {
  width: auto;
  min-height: 0;
  margin: 0;
}
/* 修正：hidden 屬性要能覆蓋 #gate 的 display:flex（否則解鎖後關卡不會消失） */
[hidden] {
  display: none !important;
}