@import url("https://fonts.googleapis.com/css2?family=Poppins:wght@300;400;500;600;700&display=swap");
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: "Poppins", sans-serif;
  font-size: 16px;
}
a {
  text-decoration: none;
  color: #000;
}
button {
    padding: 1.5% 3%;
    font-size: 1.5rem;
    background-color: #cfdcda;
    border-radius: 50px;
    border: none;
    cursor: pointer;
    color: #282828;
    transition: transform 0.2s ease-in-out;
    margin-top: 2%;
}
.Book {
    line-height: 40px;
}

button:hover {
  background-color: #b6c2c0;
  color: #282828;
}


.center {
  display: flex;
  justify-content: center;
  align-items: center;
}
.nav {
    display: flex;
    justify-content: right;
    list-style: none;
}
form {
    line-height: 18px;
}
body {
    background-image: url('bg.jpg');
    animation-name: myanimation;
    animation-duration: 80s;
    animation-timing-function:ease;
    animation-iteration-count: infinite;
    overflow-x: hidden;
    padding: 5%;
}
@keyframes myanimation {
    0% {
        background-position: 0 0;
    }

    100% {
        background-position: 100% 100%;
    }
}
/* header  */
header {
  margin-bottom: 5%;
}

header img {
  width: 50%;
  height: 50%;
  transition: all 0.3s ease;
}

header img:hover {
  transform: scale(1.05);
}

nav {
    margin-bottom: 5%;
    background-color: darkslategrey;
    padding: 1.5%;
    border-radius: 50px;
}

nav ul li {
  margin: 0 2%;
}

    nav ul li a {
        color: antiquewhite;
        font-size: 2rem;
        text-decoration: none;
        padding: 10px;
        transition: all 0.3s ease;
    }
        nav ul li a:hover {
            color:white; /* 在hover时更改文字颜色 */
            padding: 15px; /* 在hover时增加内边距 */
        }

button:active {
    transform: scale(1.1); /* 点击时将按钮放大10% */
}

#promotion {
  position: relative;
  height: 200px;
  margin-bottom: 2%;
}

#promotion::before {
  z-index: -1;
  border-radius: 30px;
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-image: url("https://images.unsplash.com/photo-1618681462303-7a8bfebfdcca?ixlib=rb-4.0.3&ixid=MnwxMjA3fDB8MHxwaG90by1wYWdlfHx8fGVufDB8fHx8&auto=format&fit=crop&w=1740&q=80");
  background-position: center;
  background-attachment: fixed;
  /* filter: contrast(100%); */
  filter: blur(3px);
}

#promotion-content {
  flex-direction: column;
}

#promotion-content h2 {
  color: #fff;
  font-size: 2.5rem;
  margin-bottom: 1%;
}
    #promotion-content h3 {
        color: #fff;
        font-size: 2em;
        margin-bottom: 1%;
    }
h1 {
    color: black;
    font-size: 3rem;
    margin-bottom: 1%;
}
      h2 {
        color: black;
        font-size: 2.5rem;
        margin-bottom: 1%;
    }

    h3 {
        color: black;
        font-size: 2em;
        margin-bottom: 1%;
    }
#promotion-content p {
  color: #fff;
  font-size: 1.5rem;
  margin-bottom: 2%;
}

/* cards */

#cards {
  display: flex;
  justify-content: space-between;
  margin-bottom: 5%;
}

.card {
  width: 32%;
  background-color: #fff8f1;
  border-radius: 30px;
  padding: 2%;
  box-shadow: 0 0 10px rgba(0, 0, 0, 0.2);
  transition: all 0.3s ease;
}

.card img {
  width: 100%;
  height: 250px;
  border-radius: 20px;
  margin-bottom: 2%;
}

.card h2 {
  font-size: 2rem;
  margin-bottom: 2%;
}

.card:hover {
  transform: scale(1.05);
}

/* footer  */

footer {
    text-align: center;
    color: antiquewhite;
    line-height: 25px;
    background-color: darkslategrey;
    padding: 2% 50px;
    border-radius: 50px;
  margin-top:20px;
}
html {
    scroll-behavior: smooth;
}
input:focus:invalid {
    border: 4px solid red;
}

input:focus:valid {
    border: 4px solid green;
}