/**
 * Slideshow Framework — Stylesheet
 *
 * Generic dark/light theme with clean system font stack.
 * No external font dependencies.
 */

/* ─── Dark Theme (default) ─────────────────────────────────────────────────── */
:root,
[data-theme="dark"] {
    --color-bg:            #1a1a2e;
    --color-bg-nav:        #16213e;
    --color-text:          #e0e0e0;
    --color-text-muted:    #a0a0a0;
    --color-link:          #4da6ff;
    --color-link-hover:    #80c0ff;
    --color-link-visit:    #7c9ebb;
    --color-link-active:   #80c0ff;
    --color-accent:        #4da6ff;
    --color-gallery-bg:    #0f0f23;
    --color-gallery-bd:    #333355;
    --color-thumb-bd:      #333355;
    --color-btn-bg:        #2a2a4a;
    --color-btn-text:      #e0e0e0;
    --color-btn-hover:     #3a3a5a;
    --color-divider:       #333355;
    --shadow-gallery:      0 2px 12px rgba(0,0,0,0.4);
}

/* ─── Light Theme ───────────────────────────────────────────────────────────── */
[data-theme="light"] {
    --color-bg:            #f5f5f5;
    --color-bg-nav:        #ffffff;
    --color-text:          #222222;
    --color-text-muted:    #666666;
    --color-link:          #0066cc;
    --color-link-hover:    #0088ff;
    --color-link-visit:    #555599;
    --color-link-active:   #0088ff;
    --color-accent:        #0066cc;
    --color-gallery-bg:    #ffffff;
    --color-gallery-bd:    #cccccc;
    --color-thumb-bd:      #cccccc;
    --color-btn-bg:        #e0e0e0;
    --color-btn-text:      #222222;
    --color-btn-hover:     #d0d0d0;
    --color-divider:       #dddddd;
    --shadow-gallery:      0 2px 12px rgba(0,0,0,0.1);
}

/* ─── Reset & Base ─────────────────────────────────────────────────────────── */
*, *::before, *::after {
    box-sizing: border-box;
}

body {
    margin: 0;
    padding: 0;
    background-color: var(--color-bg);
    color: var(--color-text);
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen,
                 Ubuntu, Cantarell, 'Helvetica Neue', sans-serif;
    line-height: 1.6;
    transition: background-color 0.2s ease, color 0.2s ease;
}

a:link    { color: var(--color-link); }
a:visited { color: var(--color-link-visit); }
a:hover   { color: var(--color-link-hover); }
a:active  { color: var(--color-link-active); }

img {
    max-width: 100%;
    height: auto;
}

/* ─── Site Header ──────────────────────────────────────────────────────────── */
.site-header {
    text-align: center;
    padding: 24px 10px 4px;
}

.site-title {
    font-size: 2.2rem;
    font-weight: 700;
    color: var(--color-text);
    text-decoration: none;
    display: inline-block;
    letter-spacing: -0.5px;
}

.site-title:hover {
    color: var(--color-link-hover);
}

.site-tagline {
    display: block;
    font-size: 0.95rem;
    color: var(--color-text-muted);
    margin-top: 4px;
}

/* ─── Navigation ───────────────────────────────────────────────────────────── */
.site-nav {
    display: flex;
    justify-content: center;
    align-items: center;
    flex-wrap: wrap;
    gap: 4px 20px;
    padding: 12px 20px 16px;
    text-align: center;
    background-color: var(--color-bg-nav);
    border-bottom: 1px solid var(--color-divider);
    transition: background-color 0.2s ease;
}

.nav-link {
    font-size: 1.05rem;
    font-weight: 600;
    text-decoration: none;
    color: var(--color-link);
    white-space: nowrap;
    padding: 4px 8px;
    border-radius: 4px;
    transition: background-color 0.15s ease, color 0.15s ease;
}

.nav-link:hover {
    color: var(--color-link-hover);
    background-color: var(--color-btn-hover);
}

.nav-link.active {
    color: var(--color-text);
    background-color: var(--color-btn-bg);
}

/* ─── Theme Toggle ─────────────────────────────────────────────────────────── */
.theme-toggle {
    background: var(--color-btn-bg);
    color: var(--color-btn-text);
    border: 1px solid var(--color-gallery-bd);
    border-radius: 6px;
    padding: 4px 12px;
    font-size: 0.9rem;
    cursor: pointer;
    margin-left: 12px;
    font-family: inherit;
    transition: background-color 0.15s ease;
}

.theme-toggle:hover {
    background: var(--color-btn-hover);
}

/* ─── Page Content ─────────────────────────────────────────────────────────── */
.page-content {
    max-width: 900px;
    margin: 0 auto;
    padding: 30px 20px 60px;
    text-align: center;
}

.page-content h1,
.page-content h2,
.page-content h3 {
    color: var(--color-text);
}

.page-content p {
    text-align: justify;
    margin: 0 auto 1.2em;
    max-width: 700px;
    line-height: 1.7;
}

/* ─── Slideshow Gallery ────────────────────────────────────────────────────── */
#gallery {
    border: 1px solid var(--color-gallery-bd);
    width: 85vw;
    max-width: 1000px;
    margin: 20px auto;
    text-align: center;
    background: var(--color-gallery-bg);
    border-radius: 8px;
    box-shadow: var(--shadow-gallery);
    overflow: hidden;
    transition: background-color 0.2s ease, border-color 0.2s ease;
}

#gallery img.main-image {
    margin: 20px;
    border: 0;
    width: 75vw;
    max-width: 900px;
    display: block;
    margin-left: auto;
    margin-right: auto;
    border-radius: 4px;
}

#gallery .caption {
    color: var(--color-accent);
    margin: 10px 0 4px;
    font-size: 1.05rem;
    font-weight: 600;
}

#gallery .pn {
    padding: 10px 10px 14px;
    margin: 0;
    border-top: 1px solid var(--color-divider);
}

#gallery .pn a {
    text-decoration: none;
    font-weight: 600;
    padding: 4px 8px;
    border-radius: 4px;
    transition: background-color 0.15s ease;
}

#gallery .pn a:hover {
    background-color: var(--color-btn-hover);
}

#gallery .pn a.sp {
    padding-right: 40px;
}

/* ─── Thumbnail Grid ───────────────────────────────────────────────────────── */
.thumbnail-grid {
    border-collapse: collapse;
    margin: 10px auto 20px;
}

.thumbnail-grid td {
    padding: 4px;
    text-align: center;
    vertical-align: middle;
}

.thumbnail-grid img {
    height: 75px;
    width: 50px;
    object-fit: cover;
    border: 1px solid var(--color-thumb-bd);
    border-radius: 3px;
    cursor: pointer;
    transition: opacity 0.2s ease, border-color 0.2s ease;
}

.thumbnail-grid a:hover img {
    opacity: 0.8;
    border-color: var(--color-accent);
}

.thumbnail-grid a {
    display: inline-block;
    border: 0;
}

/* ─── Image Counter ────────────────────────────────────────────────────────── */
.image-counter {
    color: var(--color-text-muted);
    font-size: 0.85rem;
    margin-bottom: 10px;
}

/* ─── Responsive — Mobile ──────────────────────────────────────────────────── */
@media (max-width: 767px) {
    .site-title {
        font-size: 1.5rem;
    }

    .site-nav {
        display: grid;
        grid-template-columns: 1fr 1fr 1fr;
        gap: 4px 8px;
        padding: 10px 10px 12px;
    }

    .nav-link {
        font-size: 0.95rem;
        padding: 6px 4px;
    }

    .theme-toggle {
        grid-column: 1 / -1;
        margin: 4px auto 0;
    }

    #gallery {
        width: 95vw;
        border-radius: 4px;
    }

    #gallery img.main-image {
        width: 90vw;
        margin: 10px auto;
    }

    .thumbnail-grid img {
        height: 50px;
        width: 35px;
    }

    .page-content p {
        text-align: left;
    }
}

/* ─── Responsive — Tablet ──────────────────────────────────────────────────── */
@media (min-width: 768px) and (max-width: 1024px) {
    .site-title {
        font-size: 1.8rem;
    }

    .nav-link {
        font-size: 1rem;
    }
}