*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --bg: #f0f4f8;
  --card: #ffffff;
  --primary: #2563eb;
  --primary-dark: #1d4ed8;
  --text: #1e293b;
  --muted: #64748b;
  --border: #e2e8f0;
  --success: #16a34a;
  --error: #dc2626;
  --radius: 12px;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  background: var(--bg);
  color: var(--text);
  font-size: 16px;
  line-height: 1.6;
  min-height: 100vh;
}

.app {
  max-width: 480px;
  margin: 0 auto;
  padding: 16px;
  min-height: 100vh;
}

.card {
  background: var(--card);
  border-radius: var(--radius);
  padding: 24px 20px;
  box-shadow: 0 1px 4px rgba(0,0,0,.08);
}

.hero { text-align: center; padding: 48px 20px; }
.hero h1 { font-size: 1.75rem; margin-bottom: 8px; }
.subtitle { color: var(--muted); margin-bottom: 32px; }

h2 { font-size: 1.25rem; margin-bottom: 12px; }
h3 { font-size: 1rem; margin: 20px 0 10px; }

.muted { color: var(--muted); font-size: 0.875rem; }
.hint { color: var(--muted); font-size: 0.8rem; margin-top: 16px; text-align: center; }
.badge {
  display: inline-block;
  background: #eff6ff;
  color: var(--primary);
  padding: 4px 12px;
  border-radius: 20px;
  font-size: 0.85rem;
  margin-bottom: 16px;
}

.btn {
  display: inline-block;
  padding: 12px 20px;
  border: none;
  border-radius: 8px;
  font-size: 1rem;
  cursor: pointer;
  text-decoration: none;
  text-align: center;
  transition: background .15s;
}
.btn-primary { background: var(--primary); color: #fff; }
.btn-primary:hover { background: var(--primary-dark); }
.btn-secondary { background: var(--border); color: var(--text); }
.btn-block { display: block; width: 100%; margin-top: 12px; }
.btn-sm { padding: 6px 12px; font-size: 0.8rem; background: #eff6ff; color: var(--primary); border-radius: 6px; text-decoration: none; }
.btn:disabled { opacity: .5; cursor: not-allowed; }

.input {
  width: 100%;
  padding: 12px;
  border: 1px solid var(--border);
  border-radius: 8px;
  font-size: 1rem;
  margin: 8px 0 12px;
}

.consent-box {
  background: #f8fafc;
  border-radius: 8px;
  padding: 16px;
  margin: 16px 0;
  font-size: 0.9rem;
}
.consent-box ul { padding-left: 20px; margin-top: 8px; }
.consent-box li { margin-bottom: 6px; }

.checkbox-label {
  display: flex;
  align-items: flex-start;
  gap: 10px;
  margin: 16px 0;
  font-size: 0.9rem;
  cursor: pointer;
}
.checkbox-label input { margin-top: 4px; width: 18px; height: 18px; }

.flash {
  padding: 12px 16px;
  border-radius: 8px;
  margin-bottom: 12px;
  font-size: 0.9rem;
}
.flash-error { background: #fef2f2; color: var(--error); }
.flash-success { background: #f0fdf4; color: var(--success); }

.progress-bar {
  height: 4px;
  background: var(--border);
  border-radius: 2px;
  margin-bottom: 16px;
  overflow: hidden;
}
.progress-fill {
  height: 100%;
  background: var(--primary);
  transition: width .3s;
}
.progress-text { font-size: 0.8rem; color: var(--muted); margin-bottom: 8px; }

.question-block { margin-bottom: 20px; }
.q-text { font-size: 0.95rem; margin-bottom: 10px; font-weight: 500; }
.q-num { color: var(--primary); margin-right: 4px; }

.likert-group { display: flex; flex-direction: column; gap: 6px; }
.likert-option {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 10px 12px;
  border: 1px solid var(--border);
  border-radius: 8px;
  cursor: pointer;
  font-size: 0.9rem;
  transition: border-color .15s, background .15s;
}
.likert-option:has(input:checked) {
  border-color: var(--primary);
  background: #eff6ff;
}
.likert-option input { width: 18px; height: 18px; flex-shrink: 0; }

.textarea {
  width: 100%;
  padding: 10px;
  border: 1px solid var(--border);
  border-radius: 8px;
  font-size: 0.95rem;
  resize: vertical;
  min-height: 72px;
  font-family: inherit;
}

.task-list { display: flex; flex-direction: column; gap: 10px; margin-top: 16px; }
.task-item {
  display: block;
  padding: 16px;
  border: 1px solid var(--border);
  border-radius: 10px;
  text-decoration: none;
  color: var(--text);
  transition: border-color .15s;
}
.task-item:hover { border-color: var(--primary); }
.task-item.done { opacity: .6; border-color: var(--success); }
.task-label { font-weight: 600; display: block; }
.task-meta { font-size: 0.8rem; color: var(--muted); }

.scenario-box {
  background: #fffbeb;
  border-left: 4px solid #f59e0b;
  padding: 16px;
  border-radius: 0 8px 8px 0;
  margin: 16px 0;
  font-size: 0.95rem;
  line-height: 1.8;
}

.video-box {
  background: #000;
  border-radius: 8px;
  overflow: hidden;
  margin: 16px 0;
}
.video-box video { width: 100%; display: block; }

.center { text-align: center; }
.success-icon {
  width: 64px; height: 64px;
  background: #dcfce7;
  color: var(--success);
  border-radius: 50%;
  font-size: 2rem;
  line-height: 64px;
  margin: 0 auto 16px;
}

.admin-header { display: flex; justify-content: space-between; align-items: center; margin-bottom: 16px; }
.link { color: var(--primary); font-size: 0.875rem; text-decoration: none; }
.inline-form { display: flex; flex-direction: column; gap: 8px; margin-bottom: 20px; }
.class-card {
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 14px;
  margin-bottom: 12px;
}
.class-title { font-weight: 600; }
.class-meta, .class-stats { font-size: 0.85rem; color: var(--muted); margin-top: 4px; }
.link-small { font-size: 0.75rem; color: var(--muted); word-break: break-all; }
.export-row { display: flex; flex-wrap: wrap; gap: 6px; margin-top: 10px; }

.nav-row { display: flex; gap: 10px; margin-top: 16px; }
.nav-row .btn { flex: 1; }

.instruction { font-size: 0.875rem; color: var(--muted); margin-bottom: 16px; padding: 10px; background: #f8fafc; border-radius: 8px; }

/* ── 实验 / 课程新增 ───────────────────────────── */
.scene-img { width: 100%; display: block; border-radius: 10px; margin: 12px 0 4px; box-shadow: 0 1px 6px rgba(0,0,0,.12); }
.scenario-box--compact { font-size: 0.85rem; line-height: 1.6; padding: 10px 12px; margin: 8px 0 12px; }
.scenario-box--compact p { margin-top: 4px; }
.note-box { background: #f8fafc; border-left: 4px solid var(--primary); padding: 12px 14px; border-radius: 0 8px 8px 0; margin: 14px 0; font-size: 0.9rem; line-height: 1.7; }
.note-box--hw { border-left-color: #f59e0b; background: #fffbeb; }
.req { color: var(--error); margin-left: 4px; }
.scale10 { display: grid; grid-template-columns: repeat(5, 1fr); gap: 6px; }
.scale10-opt { position: relative; }
.scale10-opt input { position: absolute; opacity: 0; width: 0; height: 0; }
.scale10-opt span { display: block; text-align: center; padding: 10px 0; border: 1px solid var(--border); border-radius: 8px; font-size: 0.95rem; cursor: pointer; }
.scale10-opt input:checked + span { border-color: var(--primary); background: #eff6ff; color: var(--primary); font-weight: 600; }
.badge--exp { background: #dcfce7; color: #15803d; }
.badge--ctrl { background: #fef3c7; color: #b45309; }
.returning { margin: 4px 0 16px; font-size: 0.9rem; }
.returning summary { cursor: pointer; color: var(--primary); }
video::cue { font-size: 1rem; background: rgba(15,23,42,.75); }
code { background: #f1f5f9; padding: 1px 6px; border-radius: 4px; font-size: 0.9em; }

/* ── 实验 / 课程 新增元素 ── */
.scene-img { width: 100%; border-radius: 10px; display: block; margin: 12px 0 4px; box-shadow: 0 1px 6px rgba(0,0,0,.12); }
.scenario-box--compact { font-size: 0.875rem; line-height: 1.7; padding: 12px; margin: 10px 0; }
.note-box { background: #f8fafc; border: 1px dashed var(--border); border-radius: 8px; padding: 12px; font-size: 0.9rem; line-height: 1.7; margin: 14px 0; color: #334155; }
.note-box--hw { background: #fffbeb; border-color: #fcd34d; }
.req { color: var(--error); margin-left: 4px; }
.scale10 { display: flex; flex-wrap: wrap; gap: 6px; }
.scale10-opt { position: relative; }
.scale10-opt input { position: absolute; opacity: 0; width: 0; height: 0; }
.scale10-opt span { display: inline-block; min-width: 36px; padding: 8px 0; text-align: center; border: 1px solid var(--border); border-radius: 8px; font-size: 0.9rem; cursor: pointer; }
.scale10-opt input:checked + span { background: var(--primary); color: #fff; border-color: var(--primary); }
.returning { margin: 4px 0 14px; font-size: 0.9rem; }
.returning summary { cursor: pointer; color: var(--primary); }
.badge--exp { background: #dcfce7; color: #166534; }
.badge--ctrl { background: #fef3c7; color: #92400e; }
.class-title .badge { margin: 0 0 0 8px; padding: 2px 8px; font-size: 0.75rem; vertical-align: middle; }
code { background: #f1f5f9; padding: 1px 6px; border-radius: 4px; font-size: 0.9em; }
video::cue { font-size: 1rem; background: rgba(15,23,42,.75); }

.audio-box{margin:8px 0 12px}
.audio-box audio{width:100%}
.audio-box .hint{margin-top:4px}

/* 2026-11-04 参与说明页：名字输入框上面的小标题 */
.field-label { display: block; margin: 14px 0 6px; font-weight: 600; }