:root {
    --bg:          #f0f2f5;
    --bg-surface:  #ffffff;
    --bg-raised:   #f7f8fa;
    --bg-inset:    #eaecef;
    --border:      #d0d5dd;
    --fg:          #1a1d23;
    --fg-muted:    #5a6270;
    --fg-subtle:   #8a94a6;
    --accent:      #1a6fc4;
    --accent-soft: #e8f1fb;
    --accent-text: #ffffff;
    --header-bg:   #1a6fc4;
    --header-fg:   #ffffff;
    --tag-bg:      #e8f1fb;
    --tag-fg:      #1a5fa0;
    --status-bg:   #f7f8fa;
    --status-border:#d0d5dd;
    --shadow-sm:   0 1px 3px rgba(0,0,0,0.10), 0 1px 2px rgba(0,0,0,0.06);
    --shadow-md:   0 4px 12px rgba(0,0,0,0.10);
    --radius-sm:   6px;
    --radius-md:   10px;
    --radius-lg:   14px;
    --font-mono:   'JetBrains Mono', 'Fira Mono', 'Cascadia Code', ui-monospace, monospace;
}

[data-theme="dark"] {
    --bg:          #111214;
    --bg-surface:  #1c1e22;
    --bg-raised:   #24262b;
    --bg-inset:    #16181c;
    --border:      #2e3139;
    --fg:          #d4d8e0;
    --fg-muted:    #8b909e;
    --fg-subtle:   #5a5f6e;
    --accent:      #4d9de0;
    --accent-soft: #1a2a3d;
    --accent-text: #ffffff;
    --header-bg:   #16181c;
    --header-fg:   #d4d8e0;
    --tag-bg:      #1a2a3d;
    --tag-fg:      #6eb3f0;
    --status-bg:   #16181c;
    --status-border:#2e3139;
    --shadow-sm:   0 1px 3px rgba(0,0,0,0.40), 0 1px 2px rgba(0,0,0,0.30);
    --shadow-md:   0 4px 16px rgba(0,0,0,0.50);
}

*, *::before, *::after {
    box-sizing: border-box;
}

body {
    background: var(--bg);
    color: var(--fg);
    font-family: system-ui, -apple-system, 'Segoe UI', sans-serif;
    font-size: 15px;
    line-height: 1.5;
    margin: 0;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    -webkit-font-smoothing: antialiased;
}

header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    background: var(--header-bg);
    color: var(--header-fg);
    padding: 0 1.5em;
    height: 52px;
    border-bottom: 1px solid var(--border);
    box-shadow: var(--shadow-sm);
    position: sticky;
    top: 0;
    z-index: 100;
}

header h1 {
    margin: 0;
    font-size: 1.1rem;
    font-weight: 700;
    letter-spacing: 0.02em;
    color: var(--header-fg);
}

#theme-toggle {
    background: none;
    border: 1px solid transparent;
    border-radius: var(--radius-sm);
    font-size: 1.15em;
    color: var(--header-fg);
    cursor: pointer;
    padding: 5px 8px;
    line-height: 1;
    transition: background 0.15s, border-color 0.15s;
    opacity: 0.85;
}

#theme-toggle:hover {
    opacity: 1;
    background: rgba(255,255,255,0.10);
    border-color: rgba(255,255,255,0.18);
}

[data-theme="dark"] #theme-toggle:hover {
    background: rgba(255,255,255,0.07);
}

main {
    flex: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: 2em 1.5em;
    gap: 1.5em;
}

#upload-section {
    width: 100%;
    max-width: 960px;
    background: var(--bg-surface);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 1.5em;
    box-shadow: var(--shadow-sm);
    display: flex;
    flex-direction: column;
    gap: 1em;
}

#upload-section label {
    font-weight: 600;
    font-size: 0.9rem;
    color: var(--fg-muted);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

input[type="file"] {
    display: block;
    width: 100%;
    padding: 0.65em 0.9em;
    border: 1.5px dashed var(--border);
    border-radius: var(--radius-md);
    background: var(--bg-raised);
    color: var(--fg);
    font-size: 0.95rem;
    cursor: pointer;
    transition: border-color 0.15s, background 0.15s;
}

input[type="file"]:hover {
    border-color: var(--accent);
    background: var(--accent-soft);
}

#status {
    font-family: var(--font-mono);
    font-size: 0.8rem;
    line-height: 1.6;
    white-space: pre-wrap;
    word-break: break-word;
    color: var(--fg-muted);
    background: var(--status-bg);
    border: 1px solid var(--status-border);
    border-radius: var(--radius-sm);
    padding: 0.75em 1em;
    max-height: 180px;
    overflow-y: auto;
    display: none;
}

#status:not(:empty) {
    display: block;
}

#game-container {
    width: 100%;
    max-width: 960px;
    min-height: 200px;
    background: var(--bg-inset);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 1.25em;
    overflow-x: hidden;
    overflow-y: auto;
}

.section-header {
    grid-column: 1 / -1;
    font-size: 0.75rem;
    font-weight: 700;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    color: var(--fg-subtle);
    padding: 0.25em 0 0.75em;
    border-bottom: 1px solid var(--border);
    margin-bottom: 0.25em;
}

.asset-list {
    width: 100%;
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(190px, 1fr));
    gap: 10px;
    align-items: start;
}

.asset-card {
    background: var(--bg-surface);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    padding: 10px;
    box-shadow: var(--shadow-sm);
    display: flex;
    flex-direction: column;
    gap: 6px;
    min-width: 0;
    transition: box-shadow 0.15s, border-color 0.15s;
}

.asset-card:hover {
    box-shadow: var(--shadow-md);
    border-color: var(--accent);
}

.asset-card img {
    display: block;
    width: 100%;
    height: auto;
    border-radius: var(--radius-sm);
    background: var(--bg-inset);
    border: 1px solid var(--border);
}

.asset-meta {
    font-size: 0.82rem;
    font-weight: 600;
    color: var(--fg);
    word-break: break-word;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.asset-sub {
    font-size: 0.75rem;
    color: var(--fg-muted);
    word-break: break-word;
    line-height: 1.4;
    display: -webkit-box;
    -webkit-line-clamp: 3;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.asset-actions {
    margin-top: 2px;
}

.asset-actions a {
    display: inline-block;
    background: var(--tag-bg);
    color: var(--tag-fg);
    padding: 4px 10px;
    border-radius: var(--radius-sm);
    font-size: 0.78rem;
    font-weight: 600;
    text-decoration: none;
    transition: opacity 0.15s;
}

.asset-actions a:hover {
    opacity: 0.8;
}

.placeholder {
    font-size: 0.9rem;
    color: var(--fg-subtle);
    text-align: center;
    padding: 3em 1em;
    grid-column: 1 / -1;
}

footer {
    text-align: center;
    padding: 0.9em;
    background: var(--header-bg);
    color: var(--header-fg);
    font-size: 0.8rem;
    opacity: 0.9;
    border-top: 1px solid var(--border);
}

footer a {
    color: var(--header-fg);
    opacity: 0.75;
    text-decoration: none;
}

footer a:hover {
    opacity: 1;
    text-decoration: underline;
}

@media (max-width: 600px) {
    main { padding: 1em; }
    #game-container { padding: 0.75em; }
    .asset-list { grid-template-columns: repeat(auto-fill, minmax(150px, 1fr)); }
}

::-webkit-scrollbar { width: 6px; height: 6px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: var(--border); border-radius: 99px; }
::-webkit-scrollbar-thumb:hover { background: var(--fg-subtle); }