body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: #ffffff;
    margin: 0;
    padding: 0;
}

.flashcard-group {
    display: inline-flex;
    flex-wrap: wrap;
    margin: 2px;
}

.flashcard {
    background-color: #ffffff;
    border-radius: 10px;
    display: inline-flex;
    flex-wrap: wrap;
    justify-content: center;
    align-items: center;
    font-size: 16px;
    font-family: 'Gill Sans', 'Gill Sans MT', Calibri, 'Trebuchet MS', sans-serif;
    box-shadow: 0px 4px 8px rgba(0, 0, 0, 0.1);
    cursor: pointer;
    transition: transform 0.3s ease, box-shadow 0.3s ease, background-color 0.3s ease;
    /* เพิ่ม transition สำหรับการเปลี่ยนสีพื้นหลัง */
    width: 125px;
    height: 90px;
    margin: 6px;
    padding: 5px;
    border: 2px solid transparent;
}

ul {
    background: none;
    background-color: rgba(1, 1, 1, 0.01);
}

ul li {
    margin-left: 2px;
    
}

.flashcard:hover {
    transform: scale(1);
    box-shadow: 0px 8px 16px rgba(0, 0, 0, 0.2);
    border-color: #007bff;
    background-color: #adadb424;
    /* เปลี่ยนสีพื้นหลังเมื่อ hover */
}

.navbar-brand {
    font-family: 'Lucida Sans', 'Lucida Sans Regular', 'Lucida Grande', 'Lucida Sans Unicode', Geneva, Verdana, sans-serif;
}

.flashcard div {
    text-align: center;
    color: #333333;
}

.flashcard-header {
    background-color: #007bff;
    text-align: center;
    padding: 5px;
    border-top-left-radius: 10px;
    border-top-right-radius: 10px;
    margin-bottom: 20px;
    font-weight: bold;
    color: #141313;
    text-transform: uppercase;
    background-color: rgba(226, 109, 109, 0.237);
}

.flashcard:not(:last-child) {
    margin-right: 15px;
}

.nav-item {
    font-family: 'Gill Sans', 'Gill Sans MT', Calibri, 'Trebuchet MS', sans-serif;
    font-size: 14px;
}

.nav-item:hover {
    background-color: rgba(127, 255, 212, 0.3);
    font-family: 'Gill Sans', 'Gill Sans MT', Calibri, 'Trebuchet MS', sans-serif;
    margin: 2px;
    font-weight: bold;
    color: rgba(224, 200, 200, 0.1);
    font-size: 14px;
    text-align: center;
    padding: 2px;

}
.rainbow-text {
    background-image: linear-gradient(to right, violet, indigo, blue, rgb(201, 193, 193), green, rgb(64, 62, 65), orange, red);
    -webkit-background-clip: text;
    color: transparent;
    font-weight: bold;
}
.name_u {
    margin: 5px;
    font-size: 14px;
}

.name_w {
    font-size: 17px;
    font-weight: bold;
}

#back-top {
    display: none;
    position: fixed;
    bottom: 20px;
    right: 20px;
    z-index: 99;
    font-size: 18px;
    background-color: #36313148;
    color: #fff;
    border: none;
    border-radius: 30%;
    padding: 15px;
    cursor: pointer;
  }
  
  #back-top:hover {
    background-color: #555;
  }