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

a {
  text-decoration: none;
  color: #000;
}

body {
  font-family: "Roboto", sans-serif;
  background-color: #000;
  display: flex;
  justify-content: center;
  align-items: center;
  height: 100vh;
}

ul {
  list-style: none;
}

img {
  max-width: 100%;
}

/* Bao ngoài */
.app {
  position: relative;
  width: 100%;
  height: 100%;
  max-width: 450px;
  overflow: hidden;
}

/* Video nền */
.bg-video {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  z-index: -1;
}

.content {
  position: relative;
  z-index: 1;
  height: 100%;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  align-items: center;
  padding: 0 0 1%;
}

.btn {
  width: 80%;
  margin-bottom: 10%;
  display: flex;
  flex-direction: column;
  gap: 5px;
  animation: scaleAnimation 1.2s infinite linear;
}

@keyframes scaleAnimation {
  0%,
  100% {
    transform: scale(1);
  }
  50% {
    transform: scale(1.1);
  }
}

@media screen and (max-width: 768px) {
  .btn {
    width: 90%;
  }
}