body {
            font-family: 'Segoe UI', Tahoma, sans-serif;
            margin: 0;
            display: flex;
            flex-direction: column;
            height: 100vh;
            background: var(--bg);
        }

        /* Navigační lišta */
        .top-nav {
            background: white;
            padding: 10px 25px;
            display: flex;
            align-items: center;
            box-shadow: 0 2px 8px rgba(0,0,0,0.1);
            z-index: 1000;
        }

        .btn-back {
            text-decoration: none;
            color: var(--primary);
            font-weight: bold;
            background: #f3effb;
            padding: 8px 15px;
            border-radius: 8px;
            transition: 0.3s;
        }

        .btn-back:hover { background: var(--primary); color: white; }

        .nav-title {
            margin-left: 20px;
            font-weight: 800;
            color: #555;
            text-transform: uppercase;
            border-left: 2px solid #ddd;
            padding-left: 20px;
        }

        /* Hlavní rozvržení */
        .main-content {
            display: flex;
            flex: 1;
            overflow: hidden;
        }

        /* Sidebar se seznamem */
        .sidebar {
            width: var(--sidebar-width);
            background: white;
            border-right: 1px solid #ddd;
            overflow-y: auto;
            padding: 10px;
        }

        details {
            margin-bottom: 5px;
            border-radius: 6px;
            border: 1px solid #f0f0f0;
        }

        summary {
            padding: 12px;
            cursor: pointer;
            font-weight: bold;
            background: #fafafa;
            list-style: none;
            display: flex;
            justify-content: space-between;
        }

        summary:hover { background: #fefefe; color: var(--primary); }

        details[open] summary {
            background: var(--primary);
            color: white;
            border-radius: 6px 6px 0 0;
        }

        .file-list {
            display: flex;
            flex-direction: column;
        }

        .file-link {
            padding: 10px 15px;
            text-decoration: none;
            color: #444;
            font-size: 0.9em;
            border-bottom: 1px solid #f9f9f9;
            display: flex;
            justify-content: space-between;
            align-items: center;
            transition: 0.2s;
        }

        .file-link:hover {
            background: #f3effb;
            padding-left: 20px;
            color: var(--primary);
        }

        /* Pravý náhledový panel */
        .preview-pane {
            flex: 1;
            background: #525659;
            display: flex;
            align-items: center;
            justify-content: center;
            padding: 20px;
            position: relative;
        }

        .preview-window {
            width: 100%;
            max-width: 800px;
            height: 100%;
            background: white;
            box-shadow: 0 10px 40px rgba(0,0,0,0.4);
            display: flex;
            align-items: center;
            justify-content: center;
            overflow: hidden;
            border-radius: 4px;
        }

        .preview-window img {
            max-width: 100%;
            max-height: 100%;
            object-fit: contain;
        }

        .empty-state {
            color: #aaa;
            text-align: center;
        }/* CSS Document */