body {
        font-family: 'Inter', sans-serif;
        margin: 0;
        background: #f5f7fa;
        color: #333;
    }

    html {
        scroll-behavior: smooth;
    }

    .sticky-content {
        position: sticky;
        top: 0;
        z-index: 9999;
    }

    #oferta {
        padding: 16px 16px;
    }

    header {
        background: url('../images/header.png') center/cover;
        color: #0D3B66;
        padding: 20px 10px;
        text-align: center;
    }

    header h2,
    header p {
        margin: 0;
        color: #0D3B66;
    }

    header img {
        height: 80px;
    }

    nav {
        background: white;
        display: flex;
        justify-content: center;
        gap: 20px;
        padding: 16px 20px;
        box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
        top: 0;
        z-index: 9999;
    }

    nav .nav-slider {
        position: absolute;
        bottom: 0;
        height: 3px;
        background: #007BFF;
        transition: all 0.3s ease;
        left: 0;
        width: 0;
    }

    nav a {
        font-family: 'Inter', sans-serif;
        font-weight: 500;
        font-size: 16px;
        color: #333;
        text-decoration: none;
        transition: color 0.2s ease;
    }

    nav a:hover {
        color: #007BFF;
    }

    nav a.active {
        color: #007BFF;
    }

    nav a.active::after {
        content: "";
        position: absolute;
        left: 0;
        bottom: -6px;
        width: 100%;
        height: 2px;
        background: #007BFF;
    }

    section {
        max-width: 1100px;
        margin: 0 auto;
        scroll-margin-top: 300px;
    }

    .grid {
        display: flex;
        flex-direction: column;
        gap: 16px;
    }

    .card {
        display: flex;
        flex-direction: row;
        align-items: center;
        gap: 50px;

        background-color: #ffffff;
        padding: 25px;
        border-radius: 16px;
        box-shadow: 0 5px 15px rgba(0, 0, 0, 0.05);
    }

    .card img {
        width: 300px;
        height: auto;
        object-fit: contain;
        flex-shrink: 0;
    }

    .card-content {
        flex: 1;
    }

    .details {
        display: block;
    }

    form {
        display: grid;
        gap: 8px;
        max-width: 1100px;
    }

    .form-group {
        display: flex;
        flex-direction: column;
        gap: 4px;
    }

    .input-error {
        border: 1px solid red !important;
        animation: shake 0.3s;
    }

    @keyframes shake {
        0% {
            transform: translateX(0);
        }

        25% {
            transform: translateX(-4px);
        }

        50% {
            transform: translateX(4px);
        }

        75% {
            transform: translateX(-4px);
        }

        100% {
            transform: translateX(0);
        }
    }

    .error {
        font-size: 12px;
        color: red;
        opacity: 0;
        transform: translateY(-5px);
        transition: all 0.2s ease;
    }

    .error.show {
        opacity: 1;
        transform: translateY(0);
    }

    .input-error {
        border: 1px solid red !important;
        animation: shake 0.3s;
    }

    input,
    textarea,
    select {
        appearance: none;
        -webkit-appearance: none;
        -moz-appearance: none;
        background: white;
        cursor: pointer;
        padding: 12px;
        border-radius: 8px;
        border: 1px solid #ccc;
        font-family: inherit;
    }

    input:focus,
    textarea:focus,
    select:focus {
        outline: none;
        border-color: #007BFF;
    }

    .input-error {
        border: 1px solid red !important;
    }

    select {
        background-image: url("data:image/svg+xml;utf8,<svg fill='%23333' height='20' viewBox='0 0 20 20' width='20' xmlns='http://www.w3.org/2000/svg'><path d='M5 7l5 5 5-5z'/></svg>");
        background-repeat: no-repeat;
        background-position: right 10px center;
        background-size: 16px;
    }

    .btn {
        padding: 10px 15px;
        background: #007BFF;
        color: white;
        border: none;
        border-radius: 8px;
        cursor: pointer;
    }

    footer {
        text-align: center;
        padding: 20px;
        background: #222;
        color: white;
        margin-top: 40px;
    }

    .footer-links {
        display: flex;
        justify-content: center;
        gap: 30px;
        flex-wrap: wrap;
        margin-bottom: 10px;
    }

    .socials.premium a {
        background: #1f2937;
        /* ciemny szary */
        border: 1px solid #374151;
        color: #fff;
    }

    .socials.premium a:hover {
        background: #007BFF;
    }

    #backToTop {
        position: fixed;
        bottom: 24px;
        right: 24px;
        width: 64px;
        height: 64px;
        border-radius: 50%;
        background: #007BFF;
        color: white;
        display: none;
        align-items: center;
        justify-content: center;
        cursor: pointer;
        z-index: 10000;
        box-shadow: 0 6px 20px rgba(0, 0, 0, 0.2);
        transition: transform 0.2s ease, opacity 0.2s ease;
    }

    #backToTop:hover {
        transform: translateY(-3px);
    }