/* --- Cấu hình cơ bản --- */
html {
    font-size: 14px;
    position: relative;
    min-height: 100%;
}

@media (min-width: 768px) {
    html {
        font-size: 16px;
    }
}

body {
    margin-bottom: 60px;
    /* Nền trắng tinh khôi để làm nổi bật các khối 7 màu */
    background-color: #ffffff;
    font-family: 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
    overflow-x: hidden;
}

/* --- HIỆU ỨNG 7 MÀU CHỦ ĐẠO (RAINBOW SYSTEM) --- */

/* 1. Văn bản đa sắc */
.text-rainbow {
    background: linear-gradient(to right, #ff0000, #ff7f00, #ffff00, #00ff00, #0000ff, #4b0082, #8f00ff);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    font-weight: bold;
}

/* 2. Viền khung 7 màu động (Cho Card và Box) */
.border-rainbow {
    border: 4px solid transparent !important;
    background-image: linear-gradient(white, white), linear-gradient(45deg, #ff0000, #ff7f00, #ffff00, #00ff00, #0000ff, #8f00ff);
    background-origin: border-box;
    background-clip: content-box, border-box;
    border-radius: 15px;
}

/* 3. Hiệu ứng Gradient chuyển động cho Banner/Footer */
.bg-rainbow-animated {
    background: linear-gradient(-45deg, #ee7752, #e73c7e, #23a6d5, #23d5ab, #8f00ff);
    background-size: 400% 400%;
    animation: rainbowShift 10s ease infinite;
}

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

    50% {
        background-position: 100% 50%;
    }

    100% {
        background-position: 0% 50%;
    }
}

/* --- TÙY CHỈNH CÁC THÀNH PHẦN (COMPONENTS) --- */

/* Card sản phẩm nâng cấp */
.card {
    border-radius: 15px;
    transition: all 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275);
}

    .card:hover {
        transform: translateY(-12px) scale(1.02);
        box-shadow: 0 15px 30px rgba(0,0,0,0.2);
    }

/* Nút bấm đa sắc */
.btn-rainbow {
    background-image: linear-gradient(to right, #FC466B 0%, #3F5EFB 100%);
    border: none;
    color: white;
    font-weight: bold;
    transition: 0.5s;
    background-size: 200% auto;
}

    .btn-rainbow:hover {
        background-position: right center;
        transform: scale(1.05);
    }

/* Thanh điều hướng (Navbar) */
.navbar {
    background: white !important;
    border-bottom: 3px solid;
    border-image: linear-gradient(to right, red, orange, yellow, green, blue, violet) 1;
    box-shadow: 0 4px 12px rgba(0,0,0,0.1);
}

.nav-link {
    font-weight: 600;
    position: relative;
}

    .nav-link:after {
        content: '';
        position: absolute;
        width: 0;
        height: 2px;
        bottom: 0;
        left: 0;
        background: linear-gradient(to right, red, violet);
        transition: width 0.3s;
    }

    .nav-link:hover:after {
        width: 100%;
    }

/* Input focus đa sắc */
.form-control:focus {
    border-color: #ff0000;
    box-shadow: 0 0 0 0.25rem rgba(255, 0, 0, 0.2);
}

/* Footer rực rỡ */
footer {
    border-top: 5px solid;
    border-image: linear-gradient(to right, violet, blue, green, yellow, orange, red) 1;
    background: #f8f9fa;
}