.app {
  max-width: 720px;
  margin: 0 auto;
  padding: 16px;
  font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  color: #222;
  background: radial-gradient(circle at top, #e0f0ff 0, #f5f5f7 42%, #f5f5f7 100%);
  min-height: 100vh;
  box-sizing: border-box;
}

.app-header {
  text-align: center;
  margin-bottom: 20px;
}

.logo-circle {
  width: 56px;
  height: 56px;
  margin: 0 auto 8px;
  border-radius: 50%;
  background: linear-gradient(135deg, #007aff, #34c759);
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  font-size: 1.6rem;
  box-shadow: 0 10px 25px rgba(0, 122, 255, 0.45);
}

.app-header h1 {
  font-size: 1.9rem;
  margin: 0 0 4px;
  letter-spacing: 0.03em;
}

.subtitle {
  margin: 0;
  font-size: 0.92rem;
  color: #666;
}

.app-main {
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.card {
  background: #fff;
  border-radius: 16px;
  padding: 14px 14px 16px;
  box-shadow: 0 14px 30px rgba(15, 40, 90, 0.12);
  border: 1px solid rgba(255, 255, 255, 0.7);
}

.main-card {
  padding-top: 16px;
}

.list-card {
  padding-top: 12px;
}

.card-title {
  margin: 0 0 8px;
  font-size: 1.1rem;
}

.card-header-row {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 8px;
}

.hint {
  margin: 4px 0 10px;
  font-size: 0.9rem;
  color: #666;
}

.hint.small {
  font-size: 0.85rem;
}

.hint.tiny {
  font-size: 0.78rem;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 8px 14px;
  border-radius: 999px;
  border: none;
  font-size: 0.95rem;
  cursor: pointer;
  transition: background 0.15s ease, transform 0.1s ease, box-shadow 0.15s ease;
  user-select: none;
  -webkit-tap-highlight-color: transparent;
}

.btn.primary {
  background: #007aff;
  color: #fff;
  box-shadow: 0 6px 14px rgba(0, 122, 255, 0.35);
}

.btn.primary:active {
  transform: translateY(1px);
  box-shadow: 0 3px 8px rgba(0, 122, 255, 0.35);
}

.btn.outline {
  background: #fff;
  border: 1px solid #ddd;
  color: #333;
}

.btn.outline.active {
  border-color: #007aff;
  color: #007aff;
  background: rgba(0, 122, 255, 0.06);
}

.btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
  box-shadow: none;
}

.btn.wide-btn {
  width: 100%;
  justify-content: center;
  margin-bottom: 6px;
}

.progress-group {
  margin-top: 12px;
}

.progress-header {
  display: flex;
  justify-content: space-between;
  font-size: 0.86rem;
  margin-bottom: 4px;
}

.progress-bar {
  width: 100%;
  height: 8px;
  background: #f1f1f4;
  border-radius: 999px;
  overflow: hidden;
}

.progress-inner {
  height: 100%;
  background: linear-gradient(90deg, #007aff, #34c759);
  border-radius: 999px;
  width: 0%;
  transition: width 0.1s linear;
}

.app-footer {
  margin-top: 18px;
  text-align: center;
}

.step-badge {
  font-size: 0.7rem;
  padding: 3px 8px;
  border-radius: 999px;
  border: 1px solid rgba(0, 122, 255, 0.25);
  color: #007aff;
  background: rgba(0, 122, 255, 0.06);
  white-space: nowrap;
}

.code-and-qr {
  display: flex;
  gap: 16px;
  align-items: center;
  margin-top: 6px;
  flex-direction: column;
  justify-content: center;
}

.code-block {
  flex: none;
  padding-right: 0;
}

.hidden-code {
  display: none;
}

.code-label {
  font-size: 0.82rem;
  color: #888;
  margin-bottom: 4px;
}

.code-value {
  font-variant-numeric: tabular-nums;
  font-size: 1.4rem;
  letter-spacing: 0.3em;
  padding: 4px 10px 4px 16px;
  border-radius: 10px;
  background: #0b1220;
  color: #f8fafc;
  text-align: left;
}

.code-desc {
  margin-top: 4px;
  font-size: 0.78rem;
  color: #888;
}

.qr-block {
  width: 100%;
  text-align: center;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
}

.qr-box {
  width: 180px;
  height: 180px;
  border-radius: 16px;
  background: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
  box-shadow: 0 8px 22px rgba(15, 23, 42, 0.18);
}

.qr-desc {
  margin-top: 4px;
  font-size: 0.78rem;
  color: #666;
}

.copy-btn {
  margin-top: 6px;
  width: auto;
  font-size: 0.8rem;
  padding-block: 5px;
  padding-inline: 14px;
}

.divider {
  height: 1px;
  background: linear-gradient(90deg, rgba(148, 163, 184, 0), rgba(148, 163, 184, 0.7), rgba(148, 163, 184, 0));
  margin: 10px 0 8px;
}

.send-area {
  margin-top: 4px;
}

.muted {
  color: #94a3b8;
}

.file-list {
  list-style: none;
  padding: 0;
  margin: 4px 0 0;
  max-height: 220px;
  overflow-y: auto;
}

.file-list-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
  padding: 6px 0;
  border-bottom: 1px dashed rgba(148, 163, 184, 0.5);
  font-size: 0.85rem;
}

.file-list-item:last-child {
  border-bottom: none;
}

.file-name {
  flex: 1;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.file-meta {
  font-size: 0.78rem;
  color: #94a3b8;
}

.file-status {
  font-size: 0.78rem;
  padding: 2px 6px;
  border-radius: 999px;
  white-space: nowrap;
}

.file-status.received {
  background: rgba(52, 199, 89, 0.1);
  color: #15803d;
}

.file-status.pending {
  background: rgba(234, 179, 8, 0.12);
  color: #92400e;
}

.file-status.sent {
  background: rgba(59, 130, 246, 0.12);
  color: #1d4ed8;
}

.file-action {
  border: 1px solid #d0d7e2;
  background: #fff;
  color: #1d4ed8;
  border-radius: 999px;
  padding: 4px 10px;
  font-size: 0.8rem;
  cursor: pointer;
  transition: background 0.15s ease, color 0.15s ease, border-color 0.15s ease;
}

.file-action:hover {
  background: rgba(59, 130, 246, 0.08);
  border-color: #1d4ed8;
}

.file-list-empty {
  text-align: center;
  font-size: 0.82rem;
  color: #9ca3af;
  padding: 6px 0 4px;
}

@media (min-width: 768px) {
  .app {
    padding: 24px 18px 32px;
  }

  .code-and-qr {
    flex-direction: row;
    align-items: center;
    justify-content: center;
  }

  .qr-block {
    width: 220px;
    margin: 0 auto;
  }

  .code-block {
    flex: 1;
    padding-right: 4px;
    text-align: left;
  }

  .app-header h1 {
    font-size: 2rem;
  }
}