@charset "utf-8";

/* Thiết lập khung bao ngoài */
#main {
    width: 900px;
    margin: 20px auto;
    font-family: Arial, sans-serif;
    box-shadow: 0 0 10px rgba(0, 0, 0, 0.2);
}

/* Banner */
#banner {
    height: 80px;
    background-color: rgba(0, 181, 204, 1);
    position: relative;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0 20px;
    box-sizing: border-box;
}

#title {
    font-size: 1.8rem;
    font-weight: 900;
    color: #ffff00;
    transition: color 0.2s ease;
}

#studentInfo {
    color: white;
    font-size: 1rem;
    font-weight: bold;
    text-shadow: 1px 1px 2px black;
}

/* Hiệu ứng bóng chữ khi kích hoạt checkbox */
.shadow {
    text-shadow: 3px 3px 6px rgba(0, 0, 0, 0.8) !important;
}

/* Menu chính (Dàn hàng ngang) */
#nav {
    background-color: rgba(3, 201, 169, 1);
    height: 35px;
    margin-bottom: 3px;
}

#menu {
    list-style-type: none;
    margin: 0;
    padding: 0;
    display: flex;
    justify-content: center;
}

#menu>li {
    position: relative;
    width: 140px;
    background-color: rgba(4, 147, 114, 1);
    line-height: 35px;
    text-align: center;
    border: 1px dotted #ffffff;
    box-sizing: border-box;
}

#menu>li:hover {
    background-color: rgba(3, 166, 120, 1);
}

a {
    text-decoration: none;
    color: white;
    font-weight: bold;
    display: block;
}

a:hover {
    color: #ffff00;
}

/* Menu đa cấp (Dropdown Submenu) */
#submenu {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    list-style-type: none;
    padding: 0;
    margin: 0;
    width: 140px;
    z-index: 100;
}

#submenu li {
    background-color: rgba(4, 147, 114, 1);
    border-top: 1px solid #fff;
    line-height: 30px;
}

#menu>li:hover #submenu {
    display: block;
}

/* Khu vực nội dung */
#content {
    display: flex;
    flex-direction: row;
    background-color: rgba(197, 239, 247, 1);
    min-height: 520px;
    padding: 10px;
    gap: 10px;
    box-sizing: border-box;
}

#left {
    width: 38%;
    display: flex;
    flex-direction: column;
    gap: 10px;
}

fieldset {
    border: 1px solid #009999;
    border-radius: 6px;
    padding: 10px 15px;
    background-color: #ffffff;
}

legend {
    font-weight: bold;
    color: #006666;
}

#originText,
#encText {
    width: 95%;
    padding: 6px;
    box-sizing: border-box;
    font-size: 1rem;
    margin-top: 4px;
}

#key {
    width: 60px;
    padding: 4px;
}

#btEncode {
    padding: 6px 15px;
    background-color: #009999;
    color: white;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    font-weight: bold;
    margin: 8px 0;
}

#btEncode:hover {
    background-color: #007777;
}

.guide-text {
    font-size: 0.8rem;
    color: #555;
    font-style: italic;
    margin: 4px 0;
}

/* Khung hiển thị sách bên phải */
#detail {
    width: 62%;
    background-color: #ffffff;
    border-radius: 6px;
    padding: 10px;
    box-sizing: border-box;
    display: flex;
    flex-direction: column;
    gap: 15px;
}

.book-group {
    display: flex;
    justify-content: space-around;
    flex-wrap: wrap;
}

.book-group img {
    width: 100px;
    height: 135px;
    object-fit: cover;
    border: 1px solid #ccc;
    border-radius: 4px;
    box-shadow: 2px 2px 5px rgba(0, 0, 0, 0.15);
    transition: transform 0.2s;
}

.book-group img:hover {
    transform: scale(1.05);
}

/* Footer */
#footer {
    height: 35px;
    background-color: rgba(0, 181, 204, 1);
    text-align: center;
    line-height: 35px;
    color: #ffff00;
    font-weight: bold;
}