.teacher-qr-launch {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.45rem;
  min-height: 2.6rem;
  padding: 0.65rem 1rem;
  border: 0;
  border-radius: 0.8rem;
  background: #0f766e;
  color: #fff;
  font-size: 0.78rem;
  font-weight: 800;
  box-shadow: 0 8px 20px rgb(15 118 110 / 18%);
}

.teacher-qr-launch:hover { background: #115e59; }
.teacher-qr-modal[hidden] { display: none !important; }

.teacher-qr-modal {
  position: fixed;
  inset: 0;
  z-index: 2147483646;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 1rem;
  background: rgb(15 23 42 / 68%);
  backdrop-filter: blur(8px);
}

.teacher-qr-dialog {
  position: relative;
  width: min(1120px, 100%);
  height: min(90dvh, 860px);
  display: flex;
  flex-direction: column;
  overflow: hidden;
  border-radius: 1.75rem;
  background: #fff;
  box-shadow: 0 30px 90px rgb(15 23 42 / 35%);
}

.teacher-qr-dialog > header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 1.2rem 1.4rem;
  border-bottom: 1px solid #e2e8f0;
}

.teacher-qr-dialog h2 { margin: 0; color: #0f172a; font-size: 1.2rem; font-weight: 900; }
.teacher-qr-dialog header p { margin: 0.25rem 0 0; color: #64748b; font-size: 0.78rem; }
.teacher-qr-close { width: 2.5rem; height: 2.5rem; border: 0; border-radius: 999px; background: #f1f5f9; color: #475569; font-size: 1.6rem; line-height: 1; }

.teacher-qr-toolbar {
  display: grid;
  grid-template-columns: minmax(220px, 1fr) minmax(150px, 220px) auto;
  gap: 0.65rem;
  padding: 0.9rem 1.4rem;
  background: #f8fafc;
  border-bottom: 1px solid #e2e8f0;
}

.teacher-qr-toolbar input,
.teacher-qr-toolbar select {
  min-height: 2.65rem;
  padding: 0 0.85rem;
  border: 1px solid #cbd5e1;
  border-radius: 0.8rem;
  background: #fff;
  color: #334155;
  font-size: 0.82rem;
  font-weight: 650;
  outline: none;
}

.teacher-qr-toolbar input:focus,
.teacher-qr-toolbar select:focus { border-color: #10b981; box-shadow: 0 0 0 3px rgb(16 185 129 / 12%); }

.teacher-qr-download-all {
  min-height: 2.65rem;
  padding: 0 1rem;
  border: 0;
  border-radius: 0.8rem;
  background: #10b981;
  color: #fff;
  font-size: 0.78rem;
  font-weight: 900;
}
.teacher-qr-download-all:disabled { background: #94a3b8; }

.teacher-qr-summary { display: flex; justify-content: space-between; gap: 1rem; padding: 0.7rem 1.4rem; color: #64748b; font-size: 0.75rem; border-bottom: 1px solid #f1f5f9; }
.teacher-qr-summary b { color: #0f766e; }
.teacher-qr-summary [data-type="error"] { color: #dc2626; font-weight: 700; }
.teacher-qr-summary [data-type="success"] { color: #059669; font-weight: 700; }

.teacher-qr-list {
  flex: 1;
  display: flex;
  flex-direction: column;
  gap: 0.9rem;
  padding: 1.2rem 1.4rem 2rem;
  overflow: auto;
  background: #f8fafc;
}

.teacher-qr-student-row { width: 100%; display: flex; align-items: center; gap: 0.9rem; padding: 0.85rem 1rem; border: 1px solid #e2e8f0; border-radius: 1rem; background: #fff; color: inherit; text-align: left; box-shadow: 0 4px 14px rgb(15 23 42 / 4%); }
.teacher-qr-student-row:hover { border-color: #34d399; background: #f0fdf4; }
.teacher-qr-row-number { width: 2.3rem; height: 2.3rem; flex: 0 0 auto; display: grid; place-items: center; border-radius: 0.75rem; background: #ecfdf5; color: #047857; font-size: 0.76rem; font-weight: 900; }
.teacher-qr-row-info { min-width: 0; flex: 1; }
.teacher-qr-row-info strong { display: block; overflow: hidden; color: #0f172a; font-size: 0.86rem; text-overflow: ellipsis; white-space: nowrap; }
.teacher-qr-row-info small { display: block; margin-top: 0.2rem; color: #64748b; font-size: 0.7rem; }
.teacher-qr-row-action { flex: 0 0 auto; color: #059669; font-size: 0.74rem; font-weight: 850; }
.teacher-qr-row-action b { margin-left: 0.25rem; font-size: 1.25rem; vertical-align: -0.08rem; }
.teacher-qr-empty { padding: 4rem 1rem; color: #94a3b8; text-align: center; font-size: 0.85rem; font-weight: 700; }
.teacher-qr-empty button { display: block; margin: 1rem auto 0; padding: 0.7rem 1rem; border: 0; border-radius: 0.75rem; background: #10b981; color: #fff; font-weight: 850; }
.teacher-qr-viewer[hidden] { display: none !important; }
.teacher-qr-viewer { position: absolute; inset: 0; z-index: 4; display: grid; place-items: center; padding: 1rem; background: rgb(15 23 42 / 62%); backdrop-filter: blur(5px); }
.teacher-qr-viewer > section { position: relative; width: min(420px, 100%); padding: 1.5rem; border-radius: 1.5rem; background: #fff; text-align: center; box-shadow: 0 25px 65px rgb(15 23 42 / 35%); }
.teacher-qr-viewer-close { position: absolute; top: 0.75rem; right: 0.75rem; width: 2.2rem; height: 2.2rem; border: 0; border-radius: 999px; background: #f1f5f9; color: #475569; font-size: 1.35rem; }
.teacher-qr-viewer-code { width: 300px; max-width: calc(100vw - 6rem); margin: 1.25rem auto 1rem; padding: 0.6rem; border: 1px solid #e2e8f0; border-radius: 1rem; background: #fff; }
.teacher-qr-viewer-code canvas,
.teacher-qr-viewer-code img { width: 100% !important; height: auto !important; }
.teacher-qr-viewer h3 { margin: 0; color: #0f172a; font-size: 1.05rem; font-weight: 900; }
.teacher-qr-viewer p { margin: 0.35rem 0 1rem; color: #64748b; font-size: 0.78rem; }
.teacher-qr-viewer-download { width: 100%; padding: 0.8rem; border: 0; border-radius: 0.8rem; background: #10b981; color: #fff; font-size: 0.78rem; font-weight: 900; }
.teacher-qr-render-source { position: fixed; left: -10000px; top: -10000px; width: 1px; height: 1px; overflow: hidden; }
.teacher-qr-modal-open { overflow: hidden !important; }

@media (max-width: 700px) {
  .teacher-qr-modal { align-items: flex-end; padding: 0; }
  .teacher-qr-dialog { width: 100%; height: calc(100dvh - env(safe-area-inset-top)); border-radius: 1.25rem 1.25rem 0 0; }
  .teacher-qr-dialog > header { padding: 1rem; }
  .teacher-qr-toolbar { grid-template-columns: 1fr 1fr; padding: 0.75rem 1rem; }
  .teacher-qr-toolbar input { grid-column: 1 / -1; }
  .teacher-qr-download-all { padding-inline: 0.5rem; }
  .teacher-qr-summary { align-items: flex-start; flex-direction: column; padding-inline: 1rem; }
  .teacher-qr-list { gap: 0.6rem; padding: 0.9rem 0.75rem 5rem; }
  .teacher-qr-student-row { padding: 0.75rem; gap: 0.65rem; }
  .teacher-qr-row-action { font-size: 0; }
  .teacher-qr-row-action b { font-size: 1.35rem; }
  .teacher-qr-launch { flex: 1 1 auto; }
}