body {
    margin: 0;
    font-family: Arial;
}

/* TOP HEADER */
.topHeader {
    background: black;
    color: white;
    text-align: right;
    padding: 10px;
}

.topHeader span {
    margin-left: 20px;
    display: inline-block;
}

/* NAV */
.nav {
    background: green;
}

.nav ul {
    list-style: none;
    margin: 0;
    padding: 0;
}

.nav li {
    display: inline-block;
    padding: 15px;
    color: white;
}

/* HEADER */
.header {
    display: flex;
    align-items: center;
    padding: 10px;
}

.logo {
    font-size: 24px;
    font-weight: bold;
    margin-right: 20px;
}

/* MAIN */
.main {
    display: flex;
}

/* SIDEBAR */
.sidebar {
    width: 25%;
    background: #f0f0f0;
    padding: 10px;
}

/* CONTENT */
.content {
    width: 75%;
    padding: 10px;
}

/* ITEM */
.item {
    display: inline-block;
    width: 30%;
    margin: 10px;
    border: 1px solid #ccc;
    padding: 10px;
    box-sizing: border-box;
    text-align: center;

    box-shadow: 2px 2px 5px gray;
}

.item img {
    width: 100%;
}

/* HOVER EFFECT */
.item:hover {
    transform: scale(1.05);
    filter: brightness(120%);
}

/* FOOTER */
.footer {
    background: black;
    color: white;
    text-align: center;
    padding: 15px;
}
/*bài 1*/

.menu-chinh, .menu-con {
    list-style: none;
    padding: 0;
    margin: 0;
    background-color: blue;
    font-family: Arial, sans-serif;
}

/* --- MENU CHINH */
.menu-chinh {
    display: flex; 
    width: fit-content;
}

.menu-chinh > li {
    border-right: 1px solid white; /* Phân cách trắng */
    position: relative; 
}

.menu-chinh > li > a {
    display: block;
    padding: 15px 30px;
    color: white;
    text-decoration: none;
    font-weight: bold;
    text-align: center;
}

/* --- MENU CON */
.menu-con {
    position: absolute; 
    top: 100%;         
    left: 0;
    width: 250px;
    border-top: 1px solid white;
    z-index: 999;
}

.menu-con li {
    border-bottom: 1px solid white;
}

.menu-con li a {
    display: block;
    padding: 12px 20px;
    color: white;
    text-decoration: none;
    font-size: 14px;
}

/* HIỆU ỨNG HOVER & ACTIVE */

/* Khi di chuột vào */
.menu-chinh li a:hover, .menu-con li a:hover {
    background-color: oldlace; 
    color: blue;
}


.active {
    background-color: oldlace !important;
    color: blue !important;
}
/*bai2*/
menu-dung, .sub-menu {
    list-style: none;
    padding: 0;
    margin: 0;
    background-color: #000000; 
    width: 150px;
    border: 0.5px solid #FFF;
}

#menu-dung li {
    position: relative; 
    border-bottom: 1px solid #FFF;
}

#menu-dung li a {
    display: block;
    padding: 12px 15px;
    color: #FFF;
    text-decoration: none;
    font-weight: bold;
    font-size: 13px;
}

/* Hiệu ứng khi rê chuột qua */
#menu-dung li a:hover {
    background-color: darkgray;
}


.active-gray {
    background-color: darkgray !important;
    color: white !important;
}

/* Cấp 2 và Cấp 3 */
.sub-menu {
    position: absolute;
    top: -1px;      
    left: 100%;   
    width: max-content; 
    min-width: 150px;
    display: none;  
    z-index: 100;
}


li:hover > .sub-menu {
    display: block;
}
/*bai3*/
body {
    margin: 0;
    font-family: Arial, sans-serif;
}

#menu-huit, .sub-menu, .sub-menu-3 {
    list-style: none;
    padding: 0;
    margin: 0;
    background-color: blue;
}

/*  MENU CẤP 1  */
#menu-huit {
    display: flex;        
    width: 100%;          
}

#menu-huit > li {
    flex: 1;             
    border-right: 1px solid white;
    position: relative;
    text-align: center;
}

#menu-huit > li:last-child {
    border-right: none;
}

#menu-huit > li > a {
    display: block;
    padding: 15px 0;      
    color: white;
    text-decoration: none;
    font-weight: bold;
    font-size: 13px;
    white-space: nowrap; 
}

/*  MENU CẤP 2  */
.sub-menu {
    position: absolute;
    top: 100%;
    left: 0;
    width: 250px;       
    display: none;
    z-index: 100;
}

.sub-menu li {
    border-bottom: 1px solid white;
    text-align: left;
}

.sub-menu li a {
    display: block;
    padding: 12px 20px;
    color: white;
    text-decoration: none;
}

/*  MENU CẤP 3  */
.sub-menu-3 {
    position: absolute;
    top: 0;
    left: 100%;
    width: 220px;
    display: none;
}

/* HIỆU ỨNG HOVER  */
li:hover > ul {
    display: block;
}

#menu-huit li a:hover, .active {
    background-color: oldlace !important;
    color: blue !important;
}