/* ROOT VARIABLES - Dễ dàng quản lý màu sắc */
:root {
    --primary-red: #D32F2F;
    --dark-red: #8B0000;
    --gold: #FFD700;
    --lucky-green: #1B5E20;
    --bg-light: #FFF8E1;
}

* {
    box-sizing: border-box;
    transition: all 0.3s ease; /* Tạo hiệu ứng mượt mà cho mọi thứ */
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    margin: 0;
    /* Tạo nền với họa tiết chìm chuyên nghiệp */
    background-color: #fff8e1; 
    background-image: url("https://www.transparenttextures.com/patterns/cubes.png"), 
                      linear-gradient(135deg, #fff8e1 0%, #ffecb3 100%);
    background-attachment: fixed; /* Giữ nền đứng yên khi cuộn trang tạo hiệu ứng sang trọng */
    color: #333;
    overflow-x: hidden;
}

/* Thêm hiệu ứng dải lụa đỏ trang trí ở hai bên rìa (tùy chọn) */
body::before {
    content: "";
    position: fixed;
    top: 0;
    left: 0;
    width: 10px;
    height: 100%;
    background: linear-gradient(to bottom, #8b0000, #d32f2f, #8b0000);
    z-index: 9999;
}

body::after {
    content: "";
    position: fixed;
    top: 0;
    right: 0;
    width: 10px;
    height: 100%;
    background: linear-gradient(to bottom, #8b0000, #d32f2f, #8b0000);
    z-index: 9999;
}

/* Làm cho các Container trắng trở nên hơi trong suốt để lộ nền phía sau */
.container {
    max-width: 1200px;
    margin: 40px auto;
    padding: 30px;
    background: rgba(255, 255, 255, 0.9); /* Trắng trong suốt 90% */
    border-radius: 20px;
    box-shadow: 0 10px 30px rgba(0,0,0,0.05);
    backdrop-filter: blur(5px); /* Hiệu ứng kính mờ thời thượng */
}

/* HIỆU ỨNG CHỮ CHẠY BANNER */
header {
    background: linear-gradient(rgba(139, 0, 0, 0.8), rgba(211, 47, 47, 0.8)), 
                url('https://png.pngtree.com/background/20210710/pngtree-festive-red-traditional-new-year-background-image_1054378.jpg');
    background-size: cover;
    background-position: center;
    background-blend-mode: overlay;
    color: var(--gold);
    padding: 80px 20px;
    text-align: center;
    clip-path: polygon(0 0, 100% 0, 100% 90%, 50% 100%, 0 90%); /* Cắt góc banner cho hiện đại */
}

header h1 {
    font-size: 3rem;
    text-shadow: 2px 2px 4px rgba(0,0,0,0.5);
    margin: 0;
    animation: fadeInDown 1s ease-out;
}

/* NAVIGATION HIỆN ĐẠI */
nav {
    background: rgba(27, 94, 32, 0.95);
    padding: 15px;
    text-align: center;
    position: sticky;
    top: 0;
    z-index: 1000;
    backdrop-filter: blur(5px);
}

nav a {
    color: white;
    margin: 0 20px;
    text-decoration: none;
    font-weight: 600;
    font-size: 1.1rem;
    position: relative;
}

nav a::after {
    content: '';
    position: absolute;
    width: 0;
    height: 2px;
    background: var(--gold);
    bottom: -5px;
    left: 0;
    transition: 0.3s;
}

nav a:hover::after {
    width: 100%;
}

.nav-scrolled {
    background: rgba(139, 0, 0, 0.9) !important;
    box-shadow: 0 5px 15px rgba(0,0,0,0.3);
}

/* CONTAINER & CARDS */
.container {
    max-width: 1200px;
    margin: 40px auto;
    padding: 0 20px;
}

.section-title {
    text-align: center;
    color: var(--dark-red);
    font-size: 2.5rem;
    margin-bottom: 40px;
    position: relative;
}

.section-title::before {
    content: '🧧';
    margin-right: 10px;
}

/* HIỆU ỨNG HOVER ẢNH - CHUYÊN NGHIỆP */
.grid-gallery {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 25px;
}

.card {
    background: white;
    border-radius: 15px;
    overflow: hidden;
    box-shadow: 0 10px 20px rgba(0,0,0,0.1);
    border: 1px solid #eee;
}

.card:hover {
    transform: translateY(-10px);
    box-shadow: 0 15px 30px rgba(0,0,0,0.2);
}

.card img {
    width: 100%;
    height: 250px;
    object-fit: cover;
    transition: 0.5s;
}

.card:hover img {
    transform: scale(1.1);
}

.card-info {
    padding: 20px;
}

/* VIDEO RESPONSIVE */
.video-container {
    position: relative;
    padding-bottom: 56.25%;
    height: 0;
    overflow: hidden;
    border-radius: 15px;
    margin: 20px 0;
    box-shadow: 0 10px 20px rgba(0,0,0,0.2);
}

.video-container iframe {
    position: absolute;
    top: 0; left: 0; width: 100%; height: 100%;
}

/* ANIMATIONS */
@keyframes fadeInDown {
    from { opacity: 0; transform: translateY(-30px); }
    to { opacity: 1; transform: translateY(0); }
}

footer {
    background: #1a1a1a;
    color: #ccc;
    padding: 50px 20px;
    text-align: center;
}