:root {
    /* START >>HEADER-FOOTER.CSS<< START */
    --header-top-bg: #062e58;
    --header-bottom-bg: #0f1f3a;
    --footer-bg: black;
    --footer-color: white;
    /* END >>HEADER-FOOTER.CSS<< END */
}

:root[data-theme="light"] {
    /* START >>HEADER-FOOTER.CSS<< START */
    --header-top-bg: white;
    --header-bottom-bg: rgb(230, 230, 230);
    --footer-bg: white;
    --footer-color: black;
    /* END >>HEADER-FOOTER.CSS<< END */
}




header {
    /* background */

    /* dimension */
    margin: 0;
    padding: 0;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    z-index: 100;
    
    /* display */
    display: flex;
    flex-direction: column;

    /* property */
}

.header-top {
    /* background */
    background: var(--header-top-bg);

    /* dimension */
    padding: 20px 28px;
    width: 100%;

    /* display */
    display: flex;
    align-items: center;
}

.header-bottom {
    /* background */
    background: var(--header-bottom-bg);

    /* dimension */
    padding: 15px 25px;
    width: 100%;

    /* display */
    display: flex;
    align-items: center;
    justify-content: flex-start;
}

.site-logo {
    /* dimension */
    margin-top: 8px;
}

.logo-image {
    display: none;
    height: 28px;
    width: auto;
    object-fit: contain;
}

:root[data-theme="light"] .logo-image-light {
    display: block;
}

:root:not([data-theme="light"]) .logo-image-dark {
    display: block;
}

.toggle-btn {
    position: fixed;
    top: 20px;
    right: 20px;
    background: transparent;
    border: none;
    font-size: 1.8rem;
    cursor: pointer;
    transition: transform 0.2s ease;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 6px;
}

.toggle-btn:hover {
    transform: scale(1.1);
}

.theme-icon {
    display: none;
    width: 24px;
    height: 24px;
}

:root[data-theme="light"] .theme-icon-sun {
    display: block;
}

:root:not([data-theme="light"]) .theme-icon-moon {
    display: block;
}

.site-nav {
    /* display */
    display: flex;
    gap: 30px;
    align-items: center;
    justify-content: center;
}

.site-nav a {
    /* property */
    color: inherit;
    text-decoration: none;
    font-size: 0.95rem;
    letter-spacing: 0.05em;
    text-transform: uppercase;
    transition: opacity 0.2s ease;
}

.site-nav a:hover,
.site-nav a:focus {
    opacity: 0.7;
}



footer {
    /* background */
    background: var(--footer-bg);
    color: var(--footer-color);

    /* dimension */
    margin: 0;
    padding: 10px 0 12px;
    height: 30px;
    width: 100%;

    /* display */
    display: flex;
    flex-direction: row;
    justify-content: center;
    align-items: flex-end;
}

.footer-content {
    /* dimension */
    width: 100%;

    /* display */
    display: flex;
    justify-content: center;
    align-items: center;
}

.icp-link {
    color: #9a9a9a;
    text-decoration: none;
    font-size: 0.5em;
    letter-spacing: 0.05em;
    font-weight: 300;
    opacity: 0.85;
}

.icp-link:hover,
.icp-link:focus {
    text-decoration: none;
}

/* Should be placed at the bottom to override default/original settings */
/* Small screens: stack layout and shrink spacing */
@media (max-width: 768px) {
    /* START >>HEADER-FOOTER.CSS<< START */
    .header-top { padding: 10px 16px; gap: 12px; }
    .header-bottom { padding: 6px 16px 12px; }
    .site-nav { flex-wrap: wrap; gap: 14px; }
    .site-nav a { font-size: 0.9rem; letter-spacing: 0.03em; }
    /* END >>HEADER-FOOTER.CSS<< END */
}

/* Very small screens: single column, tighter text */
@media (max-width: 480px) {
    /* START >>HEADER-FOOTER.CSS<< START */
    .header-top { padding: 8px 12px; }
    .header-bottom { padding: 6px 12px 10px; }
    .site-nav { justify-content: flex-start; }
    /* END >>HEADER-FOOTER.CSS<< END */
}