:root {
    --bg: #0e0e0e;
    --surface: #141414;
    --border: #222;
    --text: #d4d4d4;
    --text-muted: #555;
    --text-dim: #888;
    --active: #f0f0f0;
    --mono: 'DM Mono', monospace;
    --sans: 'DM Sans', sans-serif;
}

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html, body { height: 100%; background: var(--bg); color: var(--text); font-family: var(--sans); font-size: 14px; }

.app { display: flex; height: 100vh; overflow: hidden; padding-top: 80px; }

.sidebar { width: 220px; flex-shrink: 0; border-right: 1px solid var(--border); display: flex; flex-direction: column; }
.sidebar-header { padding: 28px 20px 20px; border-bottom: 1px solid var(--border); }
.sidebar-header h1 { font-family: var(--mono); font-size: 11px; font-weight: 400; letter-spacing: 0.12em; text-transform: uppercase; color: var(--text-dim); }
.sidebar-header span { display: block; font-family: var(--mono); font-size: 18px; font-weight: 500; color: var(--active); margin-top: 4px; }

.nav { flex: 1; overflow-y: auto; padding: 12px 0; }
.nav::-webkit-scrollbar { display: none; }

.nav-chapter { width: 100%; background: none; border: none; display: flex; align-items: center; gap: 5px; padding: 9px 20px; cursor: pointer; color: var(--text-muted); font-family: var(--mono); font-size: 11px; font-weight: 400; letter-spacing: 0.08em; text-transform: uppercase; text-align: left; transition: color 0.15s; position: relative; }
.nav-chapter:hover { color: var(--text-dim); }
.nav-chapter.active { color: var(--active); }
.nav-chapter.active::before { content: ''; position: absolute; left: 0; top: 50%; transform: translateY(-50%); width: 2px; height: 16px; background: var(--active); border-radius: 0 1px 1px 0; }
.nav-chapter .num { color: var(--text-muted); font-size: 9px; opacity: 0.5; min-width: 16px; }
.nav-chapter .count { margin-left: auto; font-size: 9px; color: var(--text-muted); opacity: 0.5; }

.main { flex: 1; display: flex; flex-direction: column; overflow: hidden; }

.topbar { display: flex; align-items: center; justify-content: space-between; padding: 0 32px; height: 56px; border-bottom: 1px solid var(--border); flex-shrink: 0; }
.chapter-title { font-family: var(--mono); font-size: 12px; letter-spacing: 0.06em; color: var(--text-dim); text-transform: uppercase; }

.content-area { flex: 1; overflow: hidden; display: flex; }

.view-pane { flex: 1; overflow-y: auto; padding: 48px 56px; }
.view-pane::-webkit-scrollbar { width: 4px; }
.view-pane::-webkit-scrollbar-track { background: transparent; }
.view-pane::-webkit-scrollbar-thumb { background: var(--border); border-radius: 2px; }

.gallery-grid { display: flex; flex-wrap: wrap; gap: 5px; }

/* Asset Card Design */
.rectangle {
    width: 100%;
    overflow: hidden;
    border-radius: 4px;
    position: relative;
    border: 1px solid var(--border);
}

.kitbash-title-img {
    width: 100%;
    height: 100%;
    position: relative;
}

.image-kitbash {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform 0.5s ease;
}

.rectangle:hover .image-kitbash {
    transform: scale(1.05);
}

[data-category].hidden { display: none; }

.hover-label {
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    background: #111;
    color: #fff;
    font-family: var(--mono);
    font-size: 11px;
    padding: 6px 10px;
    pointer-events: none;
    opacity: 0;
    transform: translateY(100%);
    transition: opacity 0.2s cubic-bezier(0.25, 0.46, 0.45, 0.94), transform 0.4s cubic-bezier(0.34, 1.4, 0.64, 1);
    z-index: 10;
}

.hover-label.visible {
    opacity: 1;
    transform: translateY(0);
}

[data-category] a {
    display: block;
    position: relative;
    overflow: hidden;
}

@media (max-width: 768px) {
    .app {
        flex-direction: column;
        padding-top: 80px;
    }

    .sidebar {
        width: 100%;
        height: auto;
        border-right: none;
        border-bottom: 1px solid var(--border);
    }

    .sidebar-header {
        padding: 15px 20px;
        cursor: pointer;
        display: flex;
        justify-content: space-between;
        align-items: center;
    }

    .sidebar-header::after {
        content: '▼';
        font-size: 10px;
        color: var(--text-dim);
        transition: transform 0.3s;
    }

    .sidebar.open .sidebar-header::after {
        transform: rotate(180deg);
    }

    .nav {
        max-height: 0;
        overflow: hidden;
        transition: max-height 0.3s ease;
        padding: 0;
    }

    .sidebar.open .nav {
        max-height: 300px;
        overflow-y: auto;
        padding: 8px 0;
    }

    .nav-chapter {
        padding: 10px 20px;
    }

    .main {
        flex: 1;
    }

    .topbar {
        padding: 0 20px;
        height: 48px;
    }

    .chapter-title {
        font-size: 11px;
    }

    .view-pane {
        padding: 24px 20px;
    }

    .gallery-grid {
        gap: 4px;
    }
}

@media (max-width: 480px) {
    .sidebar {
        max-height: 35vh;
    }

    .sidebar-header {
        padding: 15px 20px;
    }

    .sidebar-header h1 {
        font-size: 10px;
    }

    .sidebar-header span {
        font-size: 16px;
    }

    .nav-chapter {
        padding: 7px 20px;
        font-size: 10px;
    }

    .nav-chapter .num {
        font-size: 8px;
    }

    .main {
        height: 55vh;
    }

    .topbar {
        padding: 0 15px;
        height: 44px;
    }

    .view-pane {
        padding: 20px 15px;
    }

    .gallery-grid {
        gap: 3px;
    }

    .hover-label {
        font-size: 9px;
        padding: 4px 8px;
    }
}