body {
  background-color: #fff;
  font-family: "Roboto", sans-serif;
  background-position: center;
  background-repeat: no-repeat;
  background-size: cover;
}

footer {
  font-size: 0.8rem;
  color: gray;
  text-align: center;
  padding: 10px;
  position: fixed;
  bottom: 0;
  width: 100%;
}
#content {
  display: none;
}
#password-prompt {
  display: flex;
  flex-direction: column;
  align-items: center;
  margin-top: 50px;
}

.container-fluid {
  margin-top: 30px;
}
.bg-white-50 {
  background-color: white;
  opacity: 50%;
}

.text-center h3 {
  margin-top: 15px;
}

#center_rectangle {
  border-radius: 8px;
}

.btn-primary {
  background-color: #4e73df;
  border-color: #4e73df;
}

.btn-primary:hover {
  background-color: #2e59d9;
  border-color: #2653d4;
}

table {
  background-color: #ffffff;
  border-radius: 10px;
}

img.img-thumbnail {
  box-shadow: 0 4px 8px rgba(0, 0, 0, 0.2);
}

.alert {
  font-size: 1rem;
}

#center_rectangle {
  position: absolute;
  top: 50%;
  left: 50%;
  width: 200px;
  height: 300px;
  border-radius: 10px;
  border: 5px solid transparent; /* Transparent border to use border-image */
  transform: translate(-50%, -50%);
  animation: border-move 2s infinite linear; /* Animation for moving border */
  border-image: linear-gradient(
      to right,
      darkgreen,
      lightgreen,
      yellow,
      lightgreen,
      darkgreen
    )
    1;
}

/* Animation to move the gradient along the border */
@keyframes border-move {
  0% {
    border-image-source: linear-gradient(
      to right,
      darkgreen,
      lightgreen,
      yellow,
      lightgreen,
      darkgreen
    );
  }
  100% {
    border-image-source: linear-gradient(
      to right,
      lightgreen,
      darkgreen,
      lightgreen,
      yellow,
      lightgreen
    );
  }
}

.phongthi_info {
  color: #570707;
  border-bottom: 1px solid #570707;
}

.clock {
  font-size: 1.5rem;
  color: #d10c0c;
}
#so_may {
    margin-left: 20px;
    padding-top: 15px;
    width: 80px;
    height: 80px;
    border-radius: 50%;
    background-color: darkgreen;
    animation: background-color-change 2s infinite alternate;
}

/* Animation to change the background color */
@keyframes background-color-change {
    0% {
        background-color: darkgreen;
    }
    100% {
        background-color: lightgreen;
    }
}