:root {
  --ink: #302f2a;
  --muted: #69675f;
  --line: #dcd9d1;
  --paper: #faf9f6;
  --accent: #506c50;
  --correct: #29603b;
  --wrong: #a23630;
  font-family: "PingFang TC", "Noto Sans TC", system-ui, sans-serif;
  color: var(--ink);
  background: var(--paper);
  line-height: 1.6;
}
* { box-sizing: border-box; }
body { margin: 0; }
button, input, select { font: inherit; }
button, summary { cursor: pointer; }
a { color: var(--accent); }
button:focus-visible, input:focus-visible, select:focus-visible, a:focus-visible, summary:focus-visible {
  outline: 2px solid var(--accent); outline-offset: 3px;
}
.site-shell { max-width: 1140px; margin: auto; padding: 28px 24px; }
.site-header { display: flex; align-items: center; justify-content: space-between; gap: 20px; padding-bottom: 22px; border-bottom: 1px solid var(--line); }
h1 { margin: 0; font-size: 28px; font-weight: 650; }
h2 { margin: 0; font-size: 18px; }
h3 { margin: 0; font-size: 17px; }
.site-subtitle { margin: 5px 0 0; color: var(--muted); font-size: 15px; }
.header-release { color: var(--muted); white-space: nowrap; font-size: 14px; }
.workspace { display: grid; grid-template-columns: 260px minmax(0, 1fr); gap: 28px; margin-top: 24px; align-items: start; }
.question-nav { min-width: 0; }
.nav-heading { display: flex; align-items: center; justify-content: space-between; }
.count-badge { color: var(--muted); font-size: 13px; }
.type-tabs { display: flex; gap: 8px; margin: 14px 0; }
.type-tab { flex: 1; padding: 7px; border: 1px solid var(--line); border-radius: 4px; background: white; color: var(--muted); }
.type-tab.is-active { color: var(--accent); border-color: var(--accent); background: #edf1e9; font-weight: 600; }
.field-label { display: block; margin: 8px 0 4px; font-size: 13px; color: var(--muted); }
#unitFilter, #searchInput { width: 100%; padding: 8px; border: 1px solid var(--line); border-radius: 4px; background: white; color: var(--ink); font-size: 14px; }
.search-icon { display: none; }
.question-list { margin-top: 15px; max-height: 420px; overflow: auto; }
.question-list__item { display: grid; grid-template-columns: 32px minmax(0, 1fr); gap: 8px; padding: 10px 8px; width: 100%; text-align: left; border: 0; border-bottom: 1px solid var(--line); background: transparent; color: var(--ink); }
.question-list__item.is-active { background: #e9eee4; }
.question-list__item:hover { background: #f0f0e9; }
.question-list__number { color: var(--muted); font-size: 13px; }
.question-list__label { font-size: 14px; min-width: 0; }
.question-list__unit { display: block; font-size: 12px; color: var(--muted); overflow-wrap: anywhere; }
.list-help { color: var(--muted); font-size: 12px; }
.question-panel { min-width: 0; }
.question-card { background: white; border: 1px solid var(--line); border-radius: 5px; padding: 28px; }
.question-card__topline { display: flex; flex-wrap: wrap; align-items: center; justify-content: space-between; gap: 12px; }
.question-id { font-size: 17px; font-weight: 600; }
.question-tags { display: flex; flex-wrap: wrap; gap: 8px; color: var(--muted); font-size: 13px; }
.tag { overflow-wrap: anywhere; }
.question-context { margin-top: 5px; color: var(--muted); font-size: 12px; }
#questionGroup { margin-right: 12px; }
#questionSample { display: none; }
.student-prompt { padding: 24px 0 16px; }
.section-label { margin: 0 0 12px; color: var(--muted); font-size: 14px; }
.question-stem { font-family: Georgia, "PingFang TC", serif; font-size: 23px; line-height: 2; overflow-wrap: anywhere; }
.question-stem p { margin: 0 0 16px; }
.question-stem p:last-child { margin-bottom: 0; }
.question-stem h1, .question-stem h2, .question-stem h3 { font-size: 1.1em; }
.question-stem hr { border: 0; border-top: 1px solid var(--line); }
.question-blank { display: inline-block; min-width: 4ch; border-bottom: 1px solid var(--ink); }
.inline-blank { display: inline-flex; flex-wrap: wrap; align-items: baseline; max-width: 100%; gap: 0; margin: 0 3px; vertical-align: baseline; }
.letter-cue { font: inherit; color: var(--ink); }
.blank-number { color: var(--muted); font: 12px system-ui; margin-right: 4px; }
.blank-number::after { content: "."; }
.blank-input { width: 90px; max-width: 100%; min-width: 0; min-height: 36px; padding: 2px 4px; border: 0; border-bottom: 1.5px solid var(--ink); border-radius: 0; background: transparent; color: var(--ink); text-align: center; font: inherit; line-height: 1.4; }
.blank-input:focus { outline-offset: 2px; }
.blank-input.is-correct { color: var(--correct); border-color: var(--correct); background: #f1f7ef; }
.blank-input.is-wrong { color: var(--wrong); border-color: var(--wrong); background: #fff4f2; }
.blank-status { margin-left: 5px; font: 12px system-ui; }
.blank-status.is-correct { color: var(--correct); }
.blank-status.is-wrong { color: var(--wrong); }
.response-area { margin-top: 12px; }
.fill-instruction, .choice-instruction { margin: 0; color: var(--muted); font-size: 14px; }
.fill-row { display: flex; flex-wrap: wrap; gap: 6px; }
.fill-response { display: grid; gap: 12px; }
.choice-list { display: grid; gap: 10px; margin-top: 15px; }
.choice-option { display: grid; grid-template-columns: 20px 22px minmax(0, 1fr); align-items: baseline; gap: 8px; padding: 10px 12px; border: 1px solid var(--line); border-radius: 4px; cursor: pointer; }
.choice-option:has(input:checked) { border-color: var(--accent); background: #f2f4ee; }
.choice-option.is-correct { border-color: var(--correct); background: #f1f7ef; }
.choice-option.is-wrong { border-color: var(--wrong); background: #fff4f2; }
.choice-option input { accent-color: var(--accent); }
.choice-content { overflow-wrap: anywhere; }
.question-actions { display: flex; flex-wrap: wrap; gap: 10px; margin-top: 18px; }
.primary-button, .secondary-button, .demo-button { min-height: 42px; padding: 8px 16px; border: 1px solid var(--line); border-radius: 4px; background: white; color: var(--ink); }
.primary-button { background: var(--accent); border-color: var(--accent); color: white; }
button:hover { filter: brightness(.96); }
.submission-message, .grading-result { padding: 12px; margin: 14px 0 0; border-radius: 4px; background: #f7f0dc; font-size: 15px; }
.grading-result.is-correct { background: #edf5e9; color: var(--correct); }
.grading-result.is-wrong { background: #fff0ed; color: var(--wrong); }
.teacher-demo { margin-top: 24px; padding-top: 16px; border-top: 1px solid var(--line); font-size: 14px; color: var(--muted); }
.teacher-demo summary { width: fit-content; }
.teacher-demo p { margin: 8px 0; }
.teacher-demo__actions { display: flex; flex-wrap: wrap; gap: 8px; }
.demo-button { font-size: 13px; padding: 6px 12px; }
.answer-reveal { margin-top: 20px; padding-top: 20px; border-top: 1px solid var(--line); }
.answer-reveal__header .section-label { display: none; }
.correct-answer__item { padding-top: 8px; }
.correct-answer__label { color: var(--muted); margin-right: 10px; }
.correct-answer__value { font-weight: 600; }
.hint { margin-top: 15px; padding: 14px; background: var(--paper); font-size: 15px; }
.hint__label { display: block; font-weight: 600; margin-bottom: 5px; }
.hint p { margin: 0 0 8px; }
.download-strip { margin-top: 28px; padding-top: 20px; border-top: 1px solid var(--line); display: flex; flex-wrap: wrap; gap: 20px; justify-content: space-between; align-items: center; }
.download-copy { margin: 4px 0 0; font-size: 13px; color: var(--muted); }
.download-links { display: flex; flex-wrap: wrap; gap: 12px; }
.download-link { text-decoration: none; border-bottom: 1px solid var(--accent); padding: 5px 0; font-size: 14px; }
.download-link__meta { margin-left: 8px; color: var(--muted); font-size: 12px; }
.site-footer { padding-top: 24px; color: var(--muted); font-size: 12px; }
.panel-message { padding: 40px 20px; background: white; text-align: center; }
[hidden] { display: none !important; }
@media (max-width: 760px) {
  .site-shell { padding: 20px 14px; }
  .site-header { align-items: start; }
  h1 { font-size: 23px; }
  .header-release { font-size: 12px; }
  .site-subtitle { font-size: 13px; }
  .workspace { grid-template-columns: 1fr; gap: 20px; }
  .question-list { max-height: 150px; }
  .question-card { padding: 20px 16px; }
  .question-stem { font-size: 21px; }
  .blank-input { width: 80px; }
  .download-strip { display: block; }
  .download-links { margin-top: 12px; }
}