:root {
  color-scheme: light;
  --ink: #17202a;
  --muted: #59636e;
  --line: #d9dee5;
  --surface: #fff;
  --soft: #f4f7fa;
  --brand: #155eef;
  --brand-dark: #0b46bd;
  --danger: #b42318;
  --success: #087443;
  font-family: system-ui, -apple-system, "Segoe UI", sans-serif;
}

* { box-sizing: border-box; }
[hidden] { display: none !important; }
body { margin: 0; color: var(--ink); background: var(--soft); line-height: 1.55; }
a { color: #0b57d0; }
a:hover { text-decoration-thickness: 2px; }
button, input, select, textarea { font: inherit; }
input, select, textarea { width: 100%; padding: .7rem .8rem; border: 1px solid #8b95a1; border-radius: .35rem; background: #fff; }
textarea { min-height: 3rem; resize: vertical; }
button, .button { min-height: 2.75rem; }
:focus-visible { outline: 3px solid #ffbf47; outline-offset: 2px; }
.container { width: min(70rem, calc(100% - 2rem)); margin-inline: auto; }
.site-header { background: #102a43; color: #fff; }
.nav { min-height: 4rem; display: flex; align-items: center; justify-content: space-between; gap: 1rem; }
.nav a, .site-header .link-button { color: #fff; }
.brand { font-size: 1.3rem; font-weight: 750; text-decoration: none; }
.nav-actions, .language-switcher, .language-switcher form { display: flex; align-items: center; flex-wrap: wrap; gap: .75rem; }
.nav-actions form, .language-switcher form { margin: 0; }
.user-email { color: #d8e7f5; }
.language-bar { border-bottom: 1px solid var(--line); background: var(--surface); }
.language-switcher { min-height: 2.75rem; justify-content: flex-end; font-size: .9rem; }
.link-button { width: auto; min-height: auto; padding: 0; border: 0; background: none; color: #0b57d0; text-decoration: underline; cursor: pointer; }
.link-button.active { font-weight: 700; text-decoration-thickness: 2px; }
.main-content { min-height: calc(100vh - 12rem); padding-block: 2.5rem; }
.site-footer { padding-block: 1.5rem; color: var(--muted); border-top: 1px solid var(--line); }
.skip-link { position: fixed; top: .5rem; left: .5rem; z-index: 10; padding: .7rem; background: #fff; transform: translateY(-150%); }
.skip-link:focus { transform: none; }
h1 { margin: 0 0 1rem; font-size: clamp(1.9rem, 5vw, 2.7rem); line-height: 1.15; }
h2 { line-height: 1.25; }
.eyebrow { margin: 0 0 .4rem; color: var(--muted); font-size: .82rem; font-weight: 700; letter-spacing: .06em; text-transform: uppercase; }
.hero { max-width: 42rem; padding-block: clamp(2rem, 8vw, 6rem); }
.hero > p:not(.eyebrow) { font-size: 1.2rem; color: var(--muted); }
.button { display: inline-flex; width: auto; align-items: center; justify-content: center; padding: .7rem 1rem; border: 1px solid var(--brand); border-radius: .4rem; background: var(--brand); color: #fff; font-weight: 700; text-decoration: none; cursor: pointer; }
.button:hover { background: var(--brand-dark); }
.button.secondary { background: #fff; color: var(--brand-dark); }
.page-heading { display: flex; align-items: flex-start; justify-content: space-between; gap: 1.25rem; margin-bottom: 2rem; }
.card-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(min(18rem, 100%), 1fr)); gap: 1rem; }
.card, .narrow-card, .result-card, .answer-card, .question-card, .empty-state { padding: 1.4rem; border: 1px solid var(--line); border-radius: .55rem; background: var(--surface); }
.card h2 { margin-block: .25rem; }
.narrow-card, .form-page { max-width: 42rem; margin-inline: auto; }
.stacked-form { display: grid; gap: 1.15rem; margin-top: 1.5rem; }
.publish-form { margin-top: 1rem; }
.stacked-form .button { justify-self: start; }
.field label { display: block; margin-bottom: .35rem; font-weight: 700; }
.help, .meta { color: var(--muted); font-size: .9rem; }
.error { margin: .3rem 0 0; color: var(--danger); font-weight: 650; }
.field-error input, .field-error textarea, .field-error select { border: 2px solid var(--danger); }
.error-summary, .notice { padding: 1rem; border-left: .3rem solid var(--danger); background: #fff1f0; }
.notice { border-color: #2e70d1; background: #eef5ff; }
.notice.success { border-color: var(--success); background: #ecfdf3; }
.back-link { display: inline-block; margin-bottom: 1.25rem; }
.prose { overflow-wrap: anywhere; }
.result-card, .answer-card, .question-card { margin-block: 1.5rem; }
.score { font-size: 2rem; font-weight: 800; }
.success-mark { width: 3rem; height: 3rem; margin: 0; border-radius: 50%; background: var(--success); color: #fff; font-size: 2rem; text-align: center; }
.details-list > div { display: grid; grid-template-columns: minmax(7rem, 1fr) 2fr; gap: 1rem; padding-block: .65rem; border-bottom: 1px solid var(--line); }
.details-list dt { font-weight: 700; }
.details-list dd { margin: 0; overflow-wrap: anywhere; }
.table-wrap { overflow-x: auto; background: #fff; }
table { width: 100%; border-collapse: collapse; }
th, td { padding: .8rem; border-bottom: 1px solid var(--line); text-align: left; }
th { background: #eaf0f6; }
.visually-hidden { position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px; overflow: hidden; clip: rect(0, 0, 0, 0); white-space: nowrap; border: 0; }
.management-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(min(20rem, 100%), 1fr)); gap: 1rem; }
.management-card { margin-bottom: 1rem; padding: 1.4rem; border: 1px solid var(--line); border-radius: .55rem; background: var(--surface); }
.management-card > h2:first-child { margin-top: 0; }
.bounded-form { max-width: 38rem; margin-top: 1.5rem; padding-top: 1rem; border-top: 1px solid var(--line); }
.compact-form { margin-top: 1rem; }
.compact-heading { margin-bottom: .5rem; }
.member-list { display: grid; gap: .75rem; }
.member-row { display: flex; align-items: flex-start; justify-content: space-between; gap: 1rem; padding: 1rem; border: 1px solid var(--line); border-radius: .4rem; }
.member-row h3, .member-row p { margin: 0; }
.member-row details { width: min(22rem, 100%); }
.member-row summary { color: var(--danger); font-weight: 700; cursor: pointer; }
.danger-button { border-color: var(--danger); background: var(--danger); }
.danger-button:hover { background: #912018; }
.invite-box { padding: .85rem; border: 1px solid var(--line); border-radius: .35rem; background: var(--soft); overflow-wrap: anywhere; user-select: all; }
.csv-page { max-width: 62rem; }
.csv-preview { margin-block: 1rem; }
.row-error { background: #fff1f0; }
.heading-actions, .response-actions { display: flex; flex-wrap: wrap; gap: .75rem; }
.editor-instructions { margin-bottom: 1rem; padding: 1rem; border-left: .3rem solid var(--brand); background: var(--surface); }
.editor-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(min(22rem, 100%), 1fr)); gap: 1rem; }
.question-list { display: grid; gap: 1rem; padding-left: 1.5rem; }
.question-heading { display: flex; justify-content: space-between; gap: 1rem; color: var(--muted); }
.choice-list { margin-bottom: 0; }
.publish-panel { margin-top: 1rem; padding: 1.4rem; border: 2px solid var(--brand); border-radius: .55rem; background: var(--surface); }
.submission-status { margin-block: 1.5rem; padding: 1rem 1.25rem; border: 1px solid var(--line); border-radius: .55rem; background: var(--surface); }
.assignment-response { display: grid; gap: 1rem; }
.assignment-response fieldset { min-width: 0; }
.assignment-response legend { padding-inline: .25rem; font-size: 1.25rem; font-weight: 750; }
.assignment-response textarea { margin-top: .4rem; }
.choice-fields { display: grid; gap: .65rem; margin-top: 1rem; }
.choice-field { display: flex; align-items: flex-start; gap: .65rem; padding: .75rem; border: 1px solid var(--line); border-radius: .4rem; cursor: pointer; }
.choice-field:has(input:checked) { border-color: var(--brand); background: #eef5ff; }
.choice-field input { width: auto; margin-top: .25rem; }
.recording-placeholder { margin-top: 1rem; padding: 1rem; border: 1px dashed #8b95a1; border-radius: .4rem; background: var(--soft); }
.audio-recorder { display: grid; gap: .8rem; margin-top: 1rem; padding: 1rem; border: 1px solid var(--line); border-radius: .55rem; background: var(--soft); }
.recorder-actions { display: flex; flex-wrap: wrap; gap: .5rem; }
.audio-timer { margin: 0; font-variant-numeric: tabular-nums; font-weight: 700; }
.audio-preview, .audio-recorder progress { width: 100%; }
.history-answer + .history-answer { margin-top: 1rem; padding-top: 1rem; border-top: 1px solid var(--line); }

@media (max-width: 38rem) {
  .nav, .page-heading { align-items: stretch; flex-direction: column; }
  .nav { padding-block: .8rem; }
  .nav-actions { justify-content: space-between; }
  .user-email { width: 100%; }
  .language-switcher { justify-content: flex-start; }
  .page-heading .button { align-self: flex-start; }
  .details-list > div { grid-template-columns: 1fr; gap: .2rem; }
  .member-row { flex-direction: column; }
  .question-heading { flex-direction: column; gap: .25rem; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { scroll-behavior: auto !important; }
}

/* M5 notification and grading components */
.badge {
  display: inline-block;
  min-width: 1.4em;
  padding: 0.1em 0.4em;
  border-radius: 999px;
  background: #b3261e;
  color: #fff;
  font-size: 0.75rem;
  text-align: center;
}
.notification-list { list-style: none; margin: 0; padding: 0; }
.notification-item {
  border: 1px solid #e2e2e2;
  border-radius: 8px;
  padding: 0.75rem 1rem;
  margin-bottom: 0.75rem;
}
.notification-item.unread { border-left: 4px solid #2b5c9e; }
.notification-body { text-align: left; display: block; width: 100%; padding: 0; }
.notification-text { display: block; margin-top: 0.25rem; color: inherit; }
.revision-list { list-style: none; padding-left: 0; }
.revision-list li { border-bottom: 1px solid #eee; padding: 0.5rem 0; }
.checkbox-line {
  display: flex;
  gap: 0.5rem;
  align-items: center;
  font-weight: normal;
}
.checkbox-line input { width: auto; }
.inline-actions .active { border-color: #2b5c9e; color: #2b5c9e; }

/* CourseDock · 清爽教育风主题（预览） — 覆盖在 app.css 之上 */

:root {
  --cd-brand: #2b5fd9;
  --cd-brand-strong: #2454c0;
  --cd-brand-soft: #eef3fd;
  --cd-ink: #1f2329;
  --cd-muted: #59636e;
  --cd-line: #e5e6eb;
  --cd-soft: #f5f6f8;
  --cd-surface: #ffffff;
  --cd-shadow: 0 1px 2px rgba(16, 24, 40, 0.05), 0 1px 3px rgba(16, 24, 40, 0.06);
  --cd-shadow-hover: 0 6px 16px rgba(16, 24, 40, 0.09);
  --cd-radius: 12px;
  font-family: "PingFang SC", "Noto Sans SC", "Segoe UI", system-ui,
    -apple-system, "Helvetica Neue", Arial, sans-serif;
}

* { box-sizing: border-box; }

body {
  background: var(--cd-soft);
  color: var(--cd-ink);
  line-height: 1.65;
  font-size: 0.9375rem;
}

a { color: var(--cd-brand-strong); text-decoration: none; }
a:hover { color: var(--cd-brand); }

.container { width: min(72rem, calc(100% - 2.5rem)); }

/* ---------- 顶部导航 ---------- */
.site-header {
  background: var(--cd-surface);
  color: var(--cd-ink);
  border-bottom: 1px solid var(--cd-line);
  position: sticky;
  top: 0;
  z-index: 30;
  box-shadow: var(--cd-shadow);
}
.nav { min-height: 3.75rem; }
.nav a, .site-header .link-button { color: var(--cd-ink); }
.brand {
  font-size: 1.15rem;
  font-weight: 800;
  letter-spacing: -0.01em;
  color: var(--cd-ink);
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
}
.brand-mark {
  width: 1.35rem;
  height: 1.35rem;
  flex: none;
  filter: drop-shadow(0 2px 4px rgba(43, 95, 217, 0.35));
}
.nav-actions a {
  padding: 0.4rem 0.75rem;
  border-radius: 0.5rem;
  font-weight: 500;
  color: var(--cd-muted);
}
.nav-actions a:hover { background: var(--cd-soft); color: var(--cd-ink); }
.nav-actions .badge {
  background: #b42318;
  color: #fff;
  border-radius: 999px;
  padding: 0.05rem 0.45rem;
  font-size: 0.72rem;
  font-weight: 700;
}

/* ---------- 语言切换 ---------- */
.language-bar { background: var(--cd-soft); border-bottom: 1px solid var(--cd-line); padding: 0.35rem 0; }
.language-switcher { justify-content: flex-end; font-size: 0.82rem; color: var(--cd-muted); }
.language-switcher .link-button {
  color: var(--cd-muted);
  padding: 0.15rem 0.6rem;
  border-radius: 999px;
  border: 1px solid transparent;
}
.language-switcher .link-button.active {
  background: var(--cd-surface);
  border-color: var(--cd-line);
  color: var(--cd-brand-strong);
  font-weight: 600;
  box-shadow: var(--cd-shadow);
}

/* ---------- 主内容 ---------- */
.main-content { padding-block: 1.75rem 3.5rem; }
.hero {
  max-width: 40rem;
  margin-inline: auto;
  text-align: center;
}
.hero-actions {
  display: flex;
  justify-content: center;
  gap: 0.75rem;
  flex-wrap: wrap;
  margin-top: 1.5rem;
}
.page-heading {
  display: flex;
  align-items: flex-end;
  justify-content: space-between;
  gap: 1rem;
  flex-wrap: wrap;
  margin-bottom: 1.5rem;
}
.page-heading h1 { margin: 0; font-size: 1.8rem; font-weight: 800; letter-spacing: -0.02em; }
.eyebrow {
  text-transform: uppercase;
  letter-spacing: 0.08em;
  font-size: 0.75rem;
  font-weight: 700;
  color: var(--cd-brand);
  margin: 0 0 0.35rem;
}
.heading-actions { display: flex; gap: 0.6rem; flex-wrap: wrap; }
h2 { font-size: 1.15rem; font-weight: 700; margin: 1.6rem 0 0.8rem; }
h3 { font-size: 1.02rem; font-weight: 700; }
.meta { color: var(--cd-muted); font-size: 0.88rem; }

/* ---------- 卡片 ---------- */
.card, .narrow-card, .result-card, .answer-card, .question-card,
.management-card, .empty-state, .form-page {
  background: var(--cd-surface);
  border: 1px solid var(--cd-line);
  border-radius: var(--cd-radius);
  box-shadow: var(--cd-shadow);
  padding: 1.25rem 1.4rem;
}
.form-page { max-width: 44rem; margin-inline: auto; }
.csv-page { max-width: 62rem; }
.card-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(17rem, 1fr)); gap: 1rem; }
.card {
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
  transition: transform 0.12s ease, box-shadow 0.12s ease;
}
.card:hover { transform: translateY(-2px); box-shadow: var(--cd-shadow-hover); }
.card h2 { margin: 0; font-size: 1.08rem; overflow-wrap: anywhere; }
.card .status, .status {
  align-self: flex-start;
  display: inline-block;
  background: var(--cd-brand-soft);
  color: var(--cd-brand-strong);
  font-size: 0.78rem;
  font-weight: 600;
  padding: 0.18rem 0.65rem;
  border-radius: 999px;
  white-space: nowrap;
}
.management-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(20rem, 1fr)); gap: 1rem; }
.management-card h2 { margin-top: 0; }
.empty-state {
  border-style: dashed;
  background: var(--cd-soft);
  text-align: center;
  padding: 2.5rem 1.5rem;
  box-shadow: none;
}
.empty-state h2 { margin-top: 0; }

/* ---------- 按钮 ---------- */
button, .button {
  min-height: 2.5rem;
  border-radius: 0.5rem;
  font-weight: 600;
  padding-inline: 1rem;
  cursor: pointer;
}
.button, button[type="submit"]:not(.link-button) {
  background: var(--cd-brand);
  color: #fff;
  border: 1px solid transparent;
  box-shadow: 0 1px 2px rgba(16, 24, 40, 0.12);
}
.button:hover, button[type="submit"]:not(.link-button):hover {
  background: var(--cd-brand-strong);
  color: #fff;
}
.button.secondary, button.secondary, .inline-actions .secondary {
  background: var(--cd-surface);
  color: var(--cd-ink);
  border-color: var(--cd-line);
  box-shadow: var(--cd-shadow);
}
.button.secondary:hover { border-color: var(--cd-brand); color: var(--cd-brand-strong); background: var(--cd-brand-soft); }
.button.secondary.active { border-color: var(--cd-brand); color: var(--cd-brand-strong); background: var(--cd-brand-soft); }
.link-button {
  background: none;
  border: none;
  box-shadow: none;
  color: var(--cd-brand-strong);
  padding: 0;
  min-height: auto;
  font-weight: 500;
  text-decoration: none;
}
.link-button:hover { text-decoration: underline; color: var(--cd-brand); background: none; }
.site-header .link-button {
  color: var(--cd-muted);
  padding: 0.4rem 0.75rem;
  border-radius: 0.5rem;
}
.site-header .link-button:hover {
  background: var(--cd-soft);
  color: var(--cd-ink);
  text-decoration: none;
}
.inline-actions { display: flex; gap: 0.6rem; flex-wrap: wrap; align-items: center; margin-block: 0.75rem; }

/* ---------- 表单 ---------- */
.checkbox-field {
  display: flex;
  align-items: center;
  gap: 0.55rem;
  font-weight: 500;
  cursor: pointer;
}
.field label.checkbox-field {
  display: flex;
  align-items: center;
  gap: 0.55rem;
  font-weight: 500;
  margin-bottom: 0;
}
.checkbox-field input { width: auto; accent-color: var(--cd-brand); }
.datetime-picker {
  display: flex;
  gap: 0.4rem;
  align-items: center;
  flex-wrap: wrap;
}
.datetime-picker input[type="date"] { flex: 1 1 10rem; width: auto; }
.datetime-picker select { width: auto; min-width: 4.5rem; }
.datetime-zone {
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--cd-brand-strong);
  background: var(--cd-brand-soft);
  border-radius: 0.5rem;
  padding: 0.3rem 0.55rem;
  white-space: nowrap;
}
.add-question {
  margin-top: 1rem;
  border: 1px dashed var(--cd-line);
  border-radius: var(--cd-radius);
  background: var(--cd-soft);
}
.add-question summary {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.7rem 0.9rem;
  cursor: pointer;
  font-weight: 600;
  color: var(--cd-brand-strong);
  list-style: none;
}
.add-question summary::-webkit-details-marker { display: none; }
.add-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 1.5rem;
  height: 1.5rem;
  border-radius: 50%;
  background: var(--cd-brand);
  color: #fff;
  font-weight: 700;
  line-height: 1;
}
.add-question-body { padding: 0 0.9rem 0.9rem; }
.add-question-body .stacked-form { margin-top: 0.75rem; }
.option-list {
  display: grid;
  gap: 0.5rem;
  margin-bottom: 0.5rem;
}
.option-row {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}
.option-number {
  min-width: 1.5rem;
  color: var(--cd-muted);
  font-weight: 600;
}
.option-row .option-text { flex: 1; }
.option-row .option-correct-label {
  flex: none;
  font-weight: 500;
}
.option-row .option-remove { flex: none; }
.add-option-button { align-self: flex-start; }
.collapsible-entry summary {
  cursor: pointer;
  font-weight: 700;
  color: var(--cd-brand-strong);
  list-style: none;
}
.collapsible-entry summary::-webkit-details-marker { display: none; }
.collapsible-entry[open] summary { margin-bottom: 0.5rem; }
input, select, textarea {
  border: 1px solid #d3d6dc;
  border-radius: 0.5rem;
  padding: 0.6rem 0.75rem;
  background: var(--cd-surface);
  transition: border-color 0.12s ease, box-shadow 0.12s ease;
}
input:focus, select:focus, textarea:focus {
  outline: none;
  border-color: var(--cd-brand);
  box-shadow: 0 0 0 3px rgba(43, 95, 217, 0.16);
}
label { font-weight: 600; font-size: 0.92rem; }
.stacked-form { display: grid; gap: 1rem; }
.stacked-form .field { display: grid; gap: 0.3rem; }
.help { color: var(--cd-muted); font-size: 0.82rem; }
.error, .errorlist, .field-error .error { color: #b42318; font-size: 0.85rem; }
.field-error input { border-color: #d93025; }
.error-summary {
  background: #fdecec;
  border: 1px solid #f2b8b5;
  color: #8c1d18;
  border-radius: 0.5rem;
  padding: 0.7rem 1rem;
  font-size: 0.9rem;
}

/* ---------- 提示 ---------- */
.notice {
  border-radius: 0.5rem;
  padding: 0.7rem 1rem;
  font-size: 0.92rem;
  border: 1px solid var(--cd-line);
  background: var(--cd-surface);
  margin-block: 0.6rem;
}
.notice.success { background: #e9f7ef; border-color: #b7e4c7; color: #116b3f; }
.notice.warning { background: #fff7e8; border-color: #f2d9a8; color: #7a4d0b; }
.notice.error { background: #fdecec; border-color: #f2b8b5; color: #8c1d18; }

/* ---------- 表格 ---------- */
.table-wrap {
  background: var(--cd-surface);
  border: 1px solid var(--cd-line);
  border-radius: var(--cd-radius);
  box-shadow: var(--cd-shadow);
  overflow: auto;
}
table { width: 100%; border-collapse: collapse; font-size: 0.92rem; }
thead th {
  text-align: left;
  background: #f7f8fa;
  color: var(--cd-muted);
  font-size: 0.78rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  padding: 0.7rem 1rem;
  border-bottom: 1px solid var(--cd-line);
}
tbody td { padding: 0.75rem 1rem; border-bottom: 1px solid #f0f1f4; vertical-align: top; }
tbody tr:last-child td { border-bottom: none; }
tbody tr:hover { background: #fafbfc; }

/* ---------- 详情列表 / 回执 ---------- */
.details-list { display: grid; gap: 0.5rem; margin: 0; }
.details-list > div {
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  padding: 0.6rem 0.8rem;
  background: var(--cd-soft);
  border-radius: 0.5rem;
}
.details-list dt { color: var(--cd-muted); font-weight: 600; }
.details-list dd { margin: 0; font-weight: 600; }
.result-card h2, .answer-card h2 { margin-top: 0; }

/* ---------- 录音控件 ---------- */
.audio-recorder {
  background: var(--cd-soft);
  border: 1px dashed var(--cd-line);
  border-radius: var(--cd-radius);
  padding: 1rem 1.1rem;
  display: grid;
  gap: 0.6rem;
}
.recorder-actions { display: flex; gap: 0.5rem; flex-wrap: wrap; }
.audio-timer { font-variant-numeric: tabular-nums; font-weight: 700; font-size: 1.1rem; margin: 0; }

/* ---------- 登录 / 认证页 ---------- */
.narrow-card { max-width: 26rem; margin: 2.5rem auto; padding: 2rem 1.8rem; }
.narrow-card h1 { margin-top: 0; font-size: 1.5rem; }
.narrow-card .stacked-form .button { width: 100%; }
.auth-footer {
  margin-top: 1.25rem;
  padding-top: 1rem;
  border-top: 1px solid var(--cd-line);
  display: grid;
  gap: 0.55rem;
  color: var(--cd-muted);
  font-size: 0.92rem;
}
.field-meta {
  display: flex;
  justify-content: flex-end;
  margin-top: 0.25rem;
  font-size: 0.82rem;
}

/* ---------- 教学班列表（胶囊） ---------- */
.section-list { list-style: none; margin: 0.5rem 0 0; padding: 0; display: flex; flex-wrap: wrap; gap: 0.5rem; }
.section-list a {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  flex: none;
  white-space: nowrap;
  background: var(--cd-surface);
  border: 1px solid var(--cd-line);
  border-radius: 999px;
  padding: 0.35rem 0.9rem;
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--cd-ink);
  box-shadow: var(--cd-shadow);
}
.section-list a::before {
  content: "";
  width: 0.45rem;
  height: 0.45rem;
  border-radius: 50%;
  background: var(--cd-brand);
  opacity: 0.7;
}
.section-list a:hover { border-color: var(--cd-brand); color: var(--cd-brand-strong); }

/* ---------- 两因素认证向导 ---------- */
.qr-box {
  background: #fff;
  border: 1px solid var(--cd-line);
  border-radius: var(--cd-radius);
  padding: 1rem;
  width: fit-content;
  margin: 0.5rem 0;
}
.qr-box img { display: block; width: 12rem; height: 12rem; }
hr { border: none; border-top: 1px solid var(--cd-line); margin: 1.2rem 0; }
.two-factor-card { max-width: 30rem; }

/* ---------- 其他 ---------- */
.back-link { display: inline-block; margin-bottom: 0.9rem; color: var(--cd-muted); font-size: 0.88rem; }
.back-link:hover { color: var(--cd-brand-strong); }
.site-footer { padding-block: 1rem; color: var(--cd-muted); font-size: 0.82rem; }
.skip-link:focus {
  position: fixed;
  top: 0.5rem;
  left: 0.5rem;
  background: var(--cd-surface);
  padding: 0.5rem 0.9rem;
  border-radius: 0.5rem;
  z-index: 50;
  box-shadow: var(--cd-shadow-hover);
}
progress { accent-color: var(--cd-brand); }
audio { width: 100%; }

/* ---------- 全局导航层级 ---------- */
.nav { gap: 1.5rem; }
.nav-links { display: flex; min-width: 0; align-items: center; gap: 0.25rem; }
.nav-account {
  display: flex;
  flex: none;
  align-items: center;
  gap: 0.75rem;
  margin-left: auto;
  padding-left: 1rem;
  border-left: 1px solid var(--cd-line);
}
.nav-actions { min-width: 0; margin-left: auto; flex-wrap: nowrap; }
.nav-links a {
  position: relative;
  padding: 0.45rem 0.85rem;
  white-space: nowrap;
}
.nav-links a.active {
  background: var(--cd-brand-soft);
  color: var(--cd-brand-strong);
  font-weight: 700;
}
.nav-links a.active::after {
  content: "";
  position: absolute;
  right: 0.85rem;
  bottom: -0.1rem;
  left: 0.85rem;
  height: 2px;
  border-radius: 999px;
  background: var(--cd-brand);
}
.nav-login {
  display: inline-flex;
  align-items: center;
  min-height: 2.25rem;
  padding: 0.35rem 0.9rem;
  border: 1px solid var(--cd-line);
  border-radius: 999px;
  font-weight: 600;
}

/* ---------- 页面头部与工具条 ---------- */
.page-heading + .notice { margin-top: 0; }
.toolbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
  flex-wrap: wrap;
  margin-bottom: 1.25rem;
  padding: 0.75rem 0.9rem;
  border: 1px solid var(--cd-line);
  border-radius: var(--cd-radius);
  background: var(--cd-surface);
  box-shadow: var(--cd-shadow);
}
.toolbar .inline-actions { margin: 0; }
.segmented-control {
  display: inline-flex;
  flex-wrap: wrap;
  gap: 0.25rem;
  padding: 0.25rem;
  border: 1px solid var(--cd-line);
  border-radius: 999px;
  background: var(--cd-soft);
}
.segmented-control .button,
.segmented-control .button.secondary {
  min-height: 2.1rem;
  padding: 0.3rem 0.8rem;
  border: 1px solid transparent;
  border-radius: 999px;
  background: transparent;
  box-shadow: none;
  color: var(--cd-muted);
  font-size: 0.86rem;
}
.segmented-control .button.active {
  background: var(--cd-surface);
  border-color: var(--cd-line);
  color: var(--cd-brand-strong);
  box-shadow: var(--cd-shadow);
}

/* ---------- 状态徽标 ---------- */
.status-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  flex: none;
  width: fit-content;
  padding: 0.2rem 0.6rem;
  border-radius: 999px;
  background: var(--cd-soft);
  color: var(--cd-muted);
  font-size: 0.78rem;
  font-weight: 700;
}
.status-badge::before {
  content: "";
  width: 0.45rem;
  height: 0.45rem;
  border-radius: 50%;
  background: currentColor;
}
.status-badge.published, .status-badge.success { background: #e9f7ef; color: #116b3f; }
.status-badge.warning, .status-badge.awaiting { background: #fff7e8; color: #7a4d0b; }
.status-badge.danger, .status-badge.failed { background: #fdecec; color: #8c1d18; }
.status-badge.draft { background: var(--cd-brand-soft); color: var(--cd-brand-strong); }
.card .card-meta .status-badge { white-space: nowrap; }

/* ---------- 卡片链接（整卡可点） ---------- */
.card { position: relative; }
.card .card-link { color: var(--cd-ink); text-decoration: none; }
.card .card-link::after {
  content: "";
  position: absolute;
  inset: 0;
  border-radius: inherit;
}
.card .card-link:hover { color: var(--cd-brand-strong); }
.card .card-meta {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
  margin-top: auto;
  padding-top: 0.75rem;
  border-top: 1px solid var(--cd-line);
  color: var(--cd-muted);
  font-size: 0.85rem;
}
.card .card-meta > span:first-child {
  min-width: 0;
  overflow-wrap: anywhere;
}
.card .status { position: relative; z-index: 1; }

/* ---------- 账户安全中心 ---------- */
.security-grid {
  display: grid;
  gap: 1rem;
  grid-template-columns: repeat(auto-fit, minmax(min(19rem, 100%), 1fr));
}
.security-card { display: flex; flex-direction: column; gap: 0.35rem; }
.security-card h2 { margin: 0 0 0.25rem; }
.security-card p { margin: 0; color: var(--cd-muted); font-size: 0.88rem; }
.security-card .button { align-self: flex-start; margin-top: 0.75rem; }
.device-list { list-style: none; margin: 0; padding: 0; display: grid; gap: 0.65rem; }
.device-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 0.85rem 1rem;
  border: 1px solid var(--cd-line);
  border-radius: 0.75rem;
  background: var(--cd-surface);
}
.device-item strong { display: block; }
.device-meta { color: var(--cd-muted); font-size: 0.82rem; }
.current-pill {
  flex: none;
  padding: 0.2rem 0.6rem;
  border-radius: 999px;
  background: #e9f7ef;
  color: #116b3f;
  font-size: 0.75rem;
  font-weight: 700;
}
.recovery-code-grid {
  list-style: none;
  margin: 1rem 0;
  padding: 0;
  display: grid;
  gap: 0.6rem;
  grid-template-columns: repeat(auto-fit, minmax(min(12rem, 100%), 1fr));
}
.recovery-code-grid code {
  display: block;
  padding: 0.65rem 0.75rem;
  border: 1px dashed #b9c2cc;
  border-radius: 0.5rem;
  background: var(--cd-soft);
  color: var(--cd-ink);
  font-size: 0.95rem;
  text-align: center;
  letter-spacing: 0.04em;
}

/* ---------- 通知中心 ---------- */
.notification-list { display: grid; gap: 0.7rem; margin-top: 1rem; }
.notification-item {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 0.75rem 1rem;
  margin: 0;
  border: 1px solid var(--cd-line);
  border-radius: var(--cd-radius);
  background: var(--cd-surface);
  box-shadow: var(--cd-shadow);
  padding: 0.9rem 1rem;
}
.notification-item.unread { border-left: 4px solid var(--cd-brand); }
.notification-main { display: flex; gap: 0.7rem; min-width: 0; }
.notification-dot {
  flex: none;
  width: 0.55rem;
  height: 0.55rem;
  margin-top: 0.4rem;
  border-radius: 50%;
  background: var(--cd-brand);
}
.notification-item:not(.unread) .notification-dot { background: #c3c8d0; }
.notification-content { min-width: 0; }
.notification-time { display: block; color: var(--cd-muted); font-size: 0.78rem; }
.notification-text { margin: 0.2rem 0 0; overflow-wrap: anywhere; }
.notification-actions {
  display: flex;
  flex-direction: column;
  align-items: flex-end;
  gap: 0.4rem;
}
.notification-actions form { margin: 0; }
.notification-actions .button { min-height: 2rem; padding: 0.25rem 0.7rem; font-size: 0.8rem; }

/* ---------- 评分工作台 ---------- */
.grading-layout {
  display: grid;
  gap: 1rem;
  grid-template-columns: minmax(0, 1fr) minmax(18rem, 24rem);
  align-items: start;
}
.grading-sidebar { display: grid; gap: 1rem; }
.grading-content-list { display: grid; gap: 1rem; }
.grading-content-list > h2 { margin: 0; }
.grading-content-list .answer-card { margin: 0; }
.automatic-score { margin-top: 1rem; padding-top: 1rem; border-top: 1px solid var(--cd-line); }
.automatic-score .score { margin-bottom: 0; }
.grade-history { margin-top: 1rem; }
.grading-card { padding: 1rem 1.1rem; }

/* ---------- 表单提交区 ---------- */
.form-actions {
  position: sticky;
  bottom: 0.75rem;
  z-index: 20;
  display: flex;
  justify-content: flex-end;
  gap: 0.65rem;
  flex-wrap: wrap;
  margin-top: 1.25rem;
  padding: 0.8rem;
  border: 1px solid var(--cd-line);
  border-radius: var(--cd-radius);
  background: rgba(255, 255, 255, 0.96);
  box-shadow: var(--cd-shadow-hover);
  backdrop-filter: blur(6px);
}
.response-actions { justify-content: flex-end; }
.form-actions .button, .response-actions .button { min-width: 8.5rem; }
.table-actions { text-align: right; white-space: nowrap; }
.toolbar .field { min-width: min(16rem, 100%); }
.toolbar .field input { width: 100%; }
.grading-answer .question-heading { margin-bottom: 0.75rem; }
.grading-card h2 { margin-top: 0; }

/* ---------- M6.5 workflow facts ---------- */
.submission-status {
  position: sticky;
  top: 4.5rem;
  z-index: 20;
  box-shadow: var(--cd-shadow);
}
.submission-status.is-late { border-color: #b45309; background: #fff7ed; }
.assignment-time-grid, .dashboard-facts {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(10rem, 1fr));
  gap: 0.75rem;
  margin: 0;
}
.assignment-time-grid div, .dashboard-facts div { min-width: 0; }
.assignment-time-grid dt, .dashboard-facts dt { color: var(--cd-muted); font-size: 0.85rem; }
.assignment-time-grid dd, .dashboard-facts dd { margin: 0; overflow-wrap: anywhere; font-weight: 650; }
.dashboard-priority-list .card { border-left: 0.25rem solid var(--cd-brand); }
.account-menu { position: relative; }
.account-menu summary {
  display: flex;
  align-items: center;
  gap: 0.35rem;
  cursor: pointer;
  list-style: none;
  white-space: nowrap;
}
.account-menu summary::-webkit-details-marker { display: none; }
.account-menu summary::after { content: "▾"; margin-left: 0.15rem; }
.account-menu[open] summary::after { transform: rotate(180deg); }
.account-menu[open] { z-index: 40; }
.account-menu-panel {
  position: absolute;
  top: calc(100% + 0.65rem);
  right: 0;
  width: max-content;
  min-width: 12rem;
  max-width: min(22rem, calc(100vw - 2rem));
  padding: 0.5rem;
  border: 1px solid var(--cd-line);
  border-radius: 0.6rem;
  background: var(--cd-surface);
  box-shadow: var(--cd-shadow-hover);
}
.account-menu-panel form { margin: 0; }
.account-menu-email {
  max-width: 20rem;
  margin: 0;
  padding: 0.45rem 0.7rem;
  overflow: hidden;
  color: var(--cd-muted);
  font-size: 0.85rem;
  text-overflow: ellipsis;
  white-space: nowrap;
}
.account-menu-panel .link-button, .account-menu-link {
  display: block;
  width: 100%;
  padding: 0.55rem 0.7rem;
  border-radius: 0.4rem;
  text-align: left;
  text-decoration: none;
  white-space: nowrap;
}
.account-menu-panel .link-button:hover, .account-menu-link:hover { background: var(--cd-soft); }

@media (max-width: 80rem) {
  .nav-links a { padding-inline: 0.6rem; }
  .nav-links a.active::after { right: 0.6rem; left: 0.6rem; }
}

@media (min-width: 40.01rem) and (max-width: 68rem) {
  .nav { flex-wrap: wrap; padding-block: 0.45rem; }
  .nav-actions { width: 100%; margin-left: 0; }
  .nav-links { flex: 1; }
}


/* ---------- 移动端 ---------- */
@media (max-width: 40rem) {
  .page-heading { align-items: flex-start; flex-direction: column; }
  .heading-actions { width: 100%; }
  .heading-actions .button { flex: 1; text-align: center; }
  .nav { flex-wrap: wrap; row-gap: 0.25rem; }
  .nav-actions { width: 100%; flex-wrap: wrap; justify-content: space-between; }
  .nav-links { order: 1; width: auto; flex-wrap: wrap; justify-content: flex-start; overflow-x: visible; }
  .nav-account { order: 2; margin-left: 0; padding-left: 0; border-left: 0; }
  .details-list > div { flex-direction: column; gap: 0.1rem; }
  .toolbar { align-items: stretch; flex-direction: column; }
  .segmented-control { width: 100%; justify-content: center; }
  .grading-layout { grid-template-columns: 1fr; }
  .notification-item { grid-template-columns: 1fr; }
  .notification-actions { flex-direction: row; align-items: center; justify-content: flex-start; }
  .form-actions { justify-content: stretch; }
  .form-actions .button, .response-actions .button { flex: 1; }
  .submission-status { position: static; }
}