body {
    font-family: Arial, sans-serif;
    margin: 0;
    padding: 0;
    background-image: url('back_pc.jpg');
    background-size: cover;
    background-position: center; 
    background-attachment: fixed; 
    color: #333;
}
/*---Header---*/
header {
    background-color: #b00000; 
    text-align: center;
    padding: 10px 20px;
}
header h1 {
    color: #FFD700;
    font-size: 36px;
    margin: 0 0 10px 0;
    text-transform: uppercase;
    letter-spacing: 2px;
    text-shadow: 1px 1px 3px rgba(0,0,0,0.3);
}
header p {
    color: #FFFFE0; 
    font-size: 18px;
    margin: 0;
}
/*---Body---*/
nav {
    background-color: #FFCC00; 
    padding: 15px 0;
}
nav ul {
    list-style-type: none;
    margin: 0;
    padding: 0;
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
}

nav ul li {
    margin: 0 15px;
}

nav ul li a {
    text-decoration: none;
    color: #8b0000; 
    font-weight: bold;
    font-size: 16px;
    display: inline-block; 
    transition: all 0.3s ease;

    padding: 5px 12px; 
    border: 2px solid transparent; 
    border-radius: 6px;
}

nav ul li a:hover , nav ul li a.active {
    color: #f10606;
    transform: scale(1.25);
    border: 2px solid #d22b2b; 
}
/* Phần Nội Dung Chính */
main {
    text-align: center;
    padding: 50px 20px 80px 20px;
    max-width: 1000px;
    margin: 0 auto;
}
main p {
    font-size: 16px;
    line-height: 1.8;
    color: #222; 
    margin: 0 auto;
    text-align: justify;
    text-align-last: center; 
}
/** ================= TrangChu ================= **/
.btn-start {
   display: inline-block;
    background-color: #b00000; 
    color: #ffffff;
    font-size: 18px;
    font-weight: bold;
    text-transform: uppercase;
    text-decoration: none;
    padding: 15px 40px;
    margin-top: 500px;
    border-radius: 6px; 
    box-shadow: 0 4px 6px rgba(0,0,0,0.15); 
    transition: all 0.3s ease;
}
.btn-start:hover {
    background-color: #d22b2b;
    box-shadow: 0 6px 12px rgba(0,0,0,0.25);
    transform: translateY(-3px) scale(1.15) ;
}
.logo-link {
    text-decoration: none;
}
/*----van ban---*/
.content-container {
    display: flex; 
    justify-content: space-between; 
    align-items: center; 
    margin-top: 50px; 
    margin-bottom: 50px; 
    gap: 10px
}
/*-----Hinh anh-----*/
.left-column {
    flex-basis: 30%;
}
.left-column img {
    width: 100%;
    height: auto;
    border-radius: 10px; 
    box-shadow: 0 4px 8px rgba(0,0,0,0.2); 
    transform: scale(2.4);
}
.right-column {
    flex-basis: 70%; 
    text-align: left; 
    background-color: rgba(255, 255, 255, 0.85);
    padding: 25px;
    border-radius: 10px; 
    transform: translateX(200px);
}

/*---header cua van ban---*/
.right-column h2 {
    color: #b00000;
    margin-top: 0;
}
.right-column p {
    font-size: 16px;
    line-height: 1.6;
    color: #333;
    text-align: justify;
}
.btn-start {
    margin-top: 30px; 
}
.sticky-header {
    position: sticky; 
    top: 0; 
    z-index: 1000; 
}
/* ================= CSS CHO KHỐI 3 THẺ (CARD) =============== */
.card-container {
    display: flex;
    justify-content: space-between;
    gap: 20px; 
    margin-top: 60px; 
    margin-bottom: 60px; 
}
.card {
    flex-basis: 32%; 
    background-color: #ffffff;
    border-radius: 12px;
    overflow: hidden; 
    box-shadow: 0 4px 10px rgba(0,0,0,0.1);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}
.card:hover {
    transform: translateY(-8px);
    box-shadow: 0 8px 15px rgba(0,0,0,0.2);
}
.card img {
    width: 100%;
    height: 220px;
    object-fit: cover; 
}

.card-content {
    padding: 20px;
    text-align: left;
}

.card-content h3 {
    color: #b00000;
    margin-top: 0;
    font-size: 20px;
}

.card-content p {
    font-size: 15px;
    line-height: 1.6;
    color: #444;
    margin-bottom: 25px;
}

.btn-card {
    display: inline-block;
    background-color: #b00000;
    color: #ffffff;
    padding: 10px 20px;
    border-radius: 20px; 
    text-decoration: none;
    font-size: 14px;
    font-weight: bold;
    transition: background-color 0.3s ease;
}

.btn-card:hover {
    background-color: #d22b2b;
}

.btn-start {
    margin-top: 20px;
}

.btn-fixed-contact {
    position: fixed; 
    bottom: 30px;  
    right: 30px;    
    z-index: 2000; 
    background-color: #00bbff; 
    color: #0d0c0c;         
    padding: 12px 25px;
    border-radius: 50px;    
    text-decoration: none;
    font-weight: bold;
    font-size: 15px;
    box-shadow: 0 4px 15px rgba(0,0,0,0.3);
    display: flex;
    align-items: center;
    gap: 8px;
    transition: all 0.3s ease;
}

.btn-fixed-contact:hover {
    background-color: #04ff00;
    transform: scale(1.1) translateY(-5px); 
    box-shadow: 0 6px 20px rgba(0,0,0,0.4);
}

/* ================= GioiThieu ================= */
.main-layout {
    display: flex;
    gap: 30px;
    margin-top: 30px;
    align-items: stretch; 
}
.left-main {
    flex: 1.5;
    display: flex;
}
.pic-box-large {
    width: 100%;
    position: relative;
}

.pic-box-large img {
    width: 100%;
    height: 100%; 
    object-fit: cover; 
    border-radius: 20px;
    box-shadow: 0 10px 20px rgba(0,0,0,0.15);
}

.right-main {
    flex: 1;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    gap: 20px;
}

.text-card {
    background-color: rgba(255, 255, 255, 0.9);
    padding: 20px;
    border-radius: 15px;
    box-shadow: 0 4px 10px rgba(0,0,0,0.05);
    border-left: 5px solid #FFCC00; 
}

.text-card h3 {
    margin-top: 0;
    color: #b00000;
}

.intro-box {
    background-color: rgba(255, 255, 255, 0.95); 
    padding: 15px 35px; 
    border-radius: 15px;
    box-shadow: 0 5px 15px rgba(0,0,0,0.1);
    width: 100%; 
    box-sizing: border-box; 
    
    margin-bottom: 20px; 
    border-left: 6px solid #b00000; 
}

.intro-box h3 {
    margin: 0 0 10px 0;
    color: #b00000;
    font-size: 22px;
}

.intro-box p {
    margin: 0;
    line-height: 1.5;
    text-align: justify; 
}

/* ================= PhongTuc,AmThuc,VanHoa ================= */
.pt-container {
    display: flex;
    gap: 40px;
    max-width: 1200px;
    margin: 40px auto;
    padding: 0 20px;
}
.pt-left-grid {
    flex: 5; 
    display: grid;
    grid-template-columns: 1fr 1fr; 
    gap: 20px;
    align-content: start;
}

.pt-card {
    background-color: rgba(255, 255, 255, 0.85);
    border-radius: 15px;
    padding: 20px;
    cursor: pointer; 
    display: flex;
    flex-direction: column; 
    gap: 10px;
    box-shadow: 0 4px 10px rgba(0,0,0,0.1);
    border: 2px solid transparent; 
    transition: all 0.3s ease;
}

.pt-card:hover, .pt-card.active-card {
    transform: translateY(-5px);
    background-color: #ffffff;
    border: 2px solid #b00000;
    box-shadow: 0 8px 15px rgba(0,0,0,0.15);
}

.pt-icon {
    font-size: 28px;
}

.pt-content h4 {
    margin: 0 0 5px 0;
    color: #b00000;
    font-size: 18px;
}

.pt-content p {
    margin: 0;
    font-size: 14px;
    color: #444;
    line-height: 1.5;
}


.pt-right-image {
    flex: 5; 
    display: flex;
    flex-direction: column;
    align-items: flex-end; 
}

.pt-right-image img {
    width: 100%;
    height: 450px; 
    object-fit: cover; 
    border-radius: 20px;
    box-shadow: 0 10px 25px rgba(0,0,0,0.2);
    transition: opacity 0.3s ease;
}


.pt-caption-box {
    margin-top: -20px; 
    margin-right: 20px; 
    background-color: #b00000;
    color: #FFCC00;
    padding: 10px 30px;
    border-radius: 10px;
    font-weight: bold;
    font-size: 16px;
    box-shadow: 0 4px 10px rgba(0,0,0,0.3);
    position: relative; 
    z-index: 10;
}





/*=============lien he=============*/
#trang-lien-he-main {
    display: flex;
    flex-direction: column; 
    align-items: center;
    background-color: #fdf8f5;
    padding: 50px 20px;
    font-family: Arial, sans-serif;
    gap: 40px; 
}

#trang-lien-he-main .lien-he-section {
    width: 100%;
    max-width: 850px;
    display: flex;
    flex-direction: column;
    align-items: center;
}

#trang-lien-he-main .tieu-de-section {
    color: #a80000;
    font-size: 20px;
    font-weight: bold;
    margin-bottom: 20px;
    text-align: center;
}

#trang-lien-he-main .khung-xam-container {
    background-color: #f5f5f5; 
    width: 100%;
    padding: 40px 60px;
    border-radius: 12px;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.05);
    box-sizing: border-box;
}

/* --- gop yyy --- */
#trang-lien-he-main .form-group-lienhe {
    margin-bottom: 25px;
    text-align: center;
}

#trang-lien-he-main label {
    display: block;
    margin-bottom: 12px;
    color: #000;
    font-size: 16px;
}

#trang-lien-he-main input[type="text"],
#trang-lien-he-main input[type="email"],
#trang-lien-he-main textarea {
    width: 100%;
    padding: 14px 15px;
    border: 1px solid #ccc;
    border-radius: 6px;
    box-sizing: border-box;
    font-size: 14px;
    background-color: #fff;
    color: #333;
}

#trang-lien-he-main input:focus,
#trang-lien-he-main textarea:focus {
    outline: none;
    border-color: #a80000;
    box-shadow: 0 0 5px rgba(168, 0, 0, 0.2);
}

#trang-lien-he-main .btn-gui-gop-y {
    width: 100%;
    background-color: #8b0000;
    color: #ffffff;
    padding: 16px;
    border: none;
    border-radius: 8px;
    font-size: 16px;
    cursor: pointer;
    margin-top: 15px;
    transition: background-color 0.2s ease;
}

#trang-lien-he-main .btn-gui-gop-y:hover {
    background-color: #a80000;
}

/* --- info --- */
#trang-lien-he-main .thong-tin-ca-nhan p {
    font-size: 16px;
    color: #333;
    margin: 18px 0; 
    text-align: center; 
}

#trang-lien-he-main .thong-tin-ca-nhan strong {
    color: #000; 
}

@media screen and (max-width: 768px) {
    #trang-lien-he-main .khung-xam-container {
        padding: 30px 20px;
    }
}