body {
    margin: 0;
    font-family: 'Roboto', Arial, sans-serif;
    background-color: #f0f8ff;
    color: #e0e0e0;
    line-height: 1.6;
    transition: background-color 0.3s ease;
    --main-shadow: 0 4px 10px rgba(0, 0, 0, 0.3);
    --main-color: #3f51b5;
}

.sticky-header {
    position: sticky;
    top: 0;
    background: linear-gradient(90deg, var(--main-color), #1e3b8f);
    color: white;
    padding: 15px 20px;
    box-shadow: var(--main-shadow);
    z-index: 1000;
    transition: box-shadow 0.3s ease;
}

nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 28px;
    font-family: 'Roboto Slab', serif;
    font-weight: 600;
    text-decoration: none;
    color: white;
    transition: color 0.3s ease;
}

.update-link {
    background: #d32f2f;
    color: white;
    padding: 10px 20px;
    border-radius: 8px;
    text-decoration: none;
    font-size: 15px;
    transition: background 0.3s ease, transform 0.2s ease, box-shadow 0.3s ease;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.2);
}

.update-link:hover {
    background: #b71c1c;
    transform: translateY(-2px);
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.4);
}

.image-container {
    text-align: center;
    margin: 30px 20px;
}

.promo-image {
    max-width: 100%;
    height: auto;
    border-radius: 12px;
    box-shadow: var(--main-shadow);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.promo-image:hover {
    transform: scale(1.05);
    box-shadow: 0 8px 18px rgba(0, 0, 0, 0.4);
}

.apply-button {
    display: inline-block;
    margin: 20px auto;
    padding: 12px 30px;
    background: #00796b;
    color: white;
    text-decoration: none;
    font-size: 16px;
    border-radius: 15px;
    transition: background 0.3s ease, transform 0.2s ease, box-shadow 0.3s ease;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.2);
}

.apply-button:hover {
    background: #004d40;
    transform: translateY(-2px);
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.4);
}

.modal {
    display: none;
    position: fixed;
    z-index: 1001;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    overflow: auto;
    background-color: rgba(0, 0, 0, 0.4);
    align-items: center;
    justify-content: center;
}

.modal-content {
    background-color: #fefefe;
    margin: auto;
    padding: 20px;
    border: 1px solid #888;
    width: fit-content;
    max-width: 90%;
    border-radius: 10px;
    text-align: center;
    position: relative;
}

@media (max-width: 768px) {
    .modal-content {
        max-width: 96%;
    }
}

.modal-content img {
    max-width: 200px;
    height: auto;
    display: block;
    margin: 0 auto 10px;
}

.modal-content p {
    color: #333;
    cursor: pointer;
    text-decoration: underline;
}

.hidden {
    display: none;
}

@media (max-width: 768px) {
    .logo {
        font-size: 24px;
    }

    .update-link {
        padding: 8px 16px;
        font-size: 14px;
    }

    .apply-button {
        font-size: 15px;
        padding: 10px 20px;
    }
}