message: Improve panel height
diff: <template>
  <VPopup
  v-model="open"
  + fixed
  class="download-video-panel"
  :trigger-element="triggerElement"
  >
  @@ -379,7 +380,9 @@ export default Vue.extend({
  </script>
  <style lang="scss">
  @import "common";
  +
  .download-video-panel {
  + @include no-scrollbar();
  font-size: 12px;
  top: 100px;
  left: 50%;
  @@ -387,17 +390,28 @@ export default Vue.extend({
  transition: .2s ease-out;
  z-index: 1000;
  width: 320px;
  + max-height: calc(100vh - 200px);
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  - padding: 12px;
  @include card();
  &.open {
  transform: translateX(-50%);
  }
  - > :not(:first-child) {
  + > * {
  margin-top: 12px;
  + padding: 0 12px;
  + }
  + > :first-child {
  + margin-top: 0;
  + padding-top: 12px;
  + padding-bottom: 6px;
  + }
  + > :last-child {
  + margin-top: 6px;
  + padding-top: 6px;
  + padding-bottom: 12px;
  }
  .be-textbox,
  .be-textarea {
  @@ -406,6 +420,10 @@ export default Vue.extend({
  &-header {
  @include h-center();
  align-self: stretch;
  + background-color: inherit;
  + position: sticky;
  + top: 0;
  + z-index: 1;
  .title {
  font-size: 16px;
  @@ -434,6 +452,10 @@ export default Vue.extend({
  margin-top: 4px;
  }
  &-footer {
  + position: sticky;
  + bottom: 0;
  + z-index: 1;
  + background-color: inherit;
  align-self: stretch;
  justify-content: center;
  @include h-center();
  