/* Giao diện tổng thể */
body {
    margin: 0;
    font-family: 'Poppins', sans-serif;
    background-color: #f0f2f5;
    color: #1a1a1a;
    scroll-behavior: smooth;
}

.container { max-width: 1100px; margin: 0 auto; padding: 40px 20px; }
h2 { margin-bottom: 30px; border-left: 5px solid #6366f1; padding-left: 15px; }

/* 1. Hero Section - Gradient Chuyển Động */
.hero {
    height: 350px;
    background: linear-gradient(-45deg, #6366f1, #a855f7, #ec4899);
    background-size: 400% 400%;
    animation: gradientMove 10s ease infinite;
    display: flex;
    justify-content: center;
    align-items: center;
    color: white;
}

@keyframes gradientMove {
    0% { background-position: 0% 50%; }
    50% { background-position: 100% 50%; }
    100% { background-position: 0% 50%; }
}

/* 2. Buttons - 3 kiểu khác nhau */
.group { display: flex; gap: 20px; }
.btn {
    padding: 12px 30px;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    font-weight: bold;
    transition: 0.3s;
}

.btn-bounce:hover { transform: scale(1.1); background: #6366f1; color: white; }

.btn-shine {
    background: #a855f7; color: white;
    position: relative; overflow: hidden;
}
.btn-shine::after {
    content: ''; position: absolute; top: 0; left: -100%;
    width: 100%; height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255,255,255,0.4), transparent);
    transition: 0.5s;
}
.btn-shine:hover::after { left: 100%; }

.btn-neon:hover {
    box-shadow: 0 0 20px #ec4899;
    background: #ec4899; color: white;
}

/* 3. Gallery - Zoom & Grayscale */
.gallery-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 15px; }
.img-item { overflow: hidden; border-radius: 12px; height: 200px; }
.img-item img {
    width: 100%; height: 100%; object-fit: cover;
    filter: grayscale(100%); transition: 0.5s ease;
}
.img-item:hover img { transform: scale(1.2); filter: grayscale(0%); }

/* 4. Menu - Gạch chân chạy */
.nav-menu a {
    text-decoration: none; color: #333; margin-right: 25px;
    font-weight: 500; position: relative; padding-bottom: 5px;
}
.nav-menu a::after {
    content: ''; position: absolute; bottom: 0; left: 0;
    width: 0; height: 3px; background: #6366f1; transition: 0.3s;
}
.nav-menu a:hover::after { width: 100%; }

/* 5. Cards - Đổ bóng 3D */
.card-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 30px; }
.card {
    background: white; border-radius: 20px; overflow: hidden;
    box-shadow: 0 10px 20px rgba(0,0,0,0.05);
    transition: 0.4s;
}
.card:hover {
    transform: translateY(-15px);
    box-shadow: 0 20px 40px rgba(99, 102, 241, 0.2);
}
.card img { width: 100%; height: 200px; object-fit: cover; }
.card-body { padding: 20px; text-align: center; }
.price { color: #6366f1; font-weight: bold; font-size: 1.2rem; }