.header {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    position: fixed;
    top: 0;
    left: 0;
    width: 120%;
    padding: 20px 0;
    background-color: #ffffff;
    z-index: 1000;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
    height: 8%;
    transition: top 0.3s ease;
}

.header.with-demo-warning {
    top: 45px;
}

.logo-container {
    position: absolute;
    left: 23.33%;
    transform: translateX(-50%);
    z-index: 999;
}

.logo-container img {
    width: 200px;
}

.options-container {
    position: absolute;
    top: 65px;
    left: 66.67%;
    transform: translateX(-50%);
    z-index: 999;
}

.options-container a {
    margin-right: 20px;
    color: #0e2050;
    text-decoration: none;
    position: relative;
    display: inline-block;
    font-weight: 500;
    font-size: 20px;
    transition: color 0.3s ease;
    padding: 8px 12px;
}

.options-container a::before {
    content: '';
    position: absolute;
    left: 0;
    bottom: 0;
    width: 100%;
    height: 100%;
    z-index: -1;
}

.options-container a:hover {
    text-decoration: underline;
    text-decoration-color: #ffd700;
    text-underline-offset: 8px;
}

.demo-warning {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    background-color: #fff3cd;
    color: #856404;
    border-bottom: 1px solid #ffeeba;
    padding: 8px 16px;
    font-family: system-ui, sans-serif;
    font-size: 14px;
    line-height: 1.4;
    text-align: center;
    z-index: 9999;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.05);
    height: 45px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.demo-warning strong {
    font-weight: bold;
}

.demo-warning a {
    color: #856404;
    text-decoration: underline;
}

.demo-warning code {
    background-color: #f8f9fa;
    padding: 2px 4px;
    border-radius: 3px;
    font-family: 'Courier New', monospace;
    font-size: 13px;
}

/* Responsive Design */

/* ≤ 599px */
@media (max-width: 599px) {
    .logo-container,
    .options-container {
        top: 20px;
    }

    .logo-container img {
        width: 100px;
    }

    .options-container a {
        font-size: 0.8rem;
        margin-right: 10px;
    }

    .options-container {
        left: 70%;
    }

    .header.with-demo-warning {
        top: 35px;
    }

    .demo-warning {
        height: 35px;
        font-size: 12px;
    }
}

/* 600px–799px */
@media (min-width: 600px) and (max-width: 799px) {
    .logo-container,
    .options-container {
        top: 20px;
    }

    .logo-container img {
        width: 110px;
    }

    .options-container a {
        font-size: 0.85rem;
        margin-right: 15px;
    }

    .header.with-demo-warning {
        top: 40px;
    }

    .demo-warning {
        height: 40px;
    }
}

/* 800px–1023px */
@media (min-width: 800px) and (max-width: 1023px) {
    .logo-container,
    .options-container {
        top: 10px;
    }

    .logo-container img {
        width: 120px;
    }

    .options-container a {
        font-size: 1rem;
    }
}

/* 1024px–1279px */
@media (min-width: 1024px) and (max-width: 1279px) {
    .logo-container,
    .options-container {
        top: 10px;
    }

    .logo-container img {
        width: 130px;
    }

    .options-container a {
        font-size: 1.1rem;
    }
}

/* 1280px–1439px */
@media (min-width: 1280px) and (max-width: 1439px) {
    .logo-container,
    .options-container {
        top: 10px;
    }

    .logo-container img {
        width: 170px;
    }

    .options-container a {
        font-size: 1.3rem;
    }
}

/* 1440px–1919px */
@media (min-width: 1440px) and (max-width: 1919px) {
    .logo-container,
    .options-container {
        top: 10px;
    }

    .logo-container img {
        width: 200px;
    }

    .options-container a {
        font-size: 1.5rem;
    }
}

/* 1920px and above */
@media (min-width: 1920px) {
    .logo-container,
    .options-container {
        top: 10px;
    }

    .logo-container img {
        width: 200px;
    }

    .options-container a {
        font-size: 1.5rem;
    }
}