/* Dark/Light Mode Variables */
:root { 
    --bg-color: #121212; 
    --header-bg: #000000; 
    --card-bg: #1f1f1f; 
    --text-main: #f0f0f0; 
    --text-meta: #aaa;
    --accent-color: #d32f2f; 
    --border-color: #333;
    --input-bg: #333;
    --input-text: #fff;
    --hover-bg: #333;
}

[data-theme="light"] {
    --bg-color: #f4f6f9;
    --header-bg: #ffffff;
    --card-bg: #ffffff;
    --text-main: #333333;
    --text-meta: #666666;
    /* --accent-color stays red or can be adjusted */
    --border-color: #e0e0e0;
    --input-bg: #f0f0f0;
    --input-text: #333;
    --hover-bg: #f0f0f0;
}

* { box-sizing: border-box; margin: 0; padding: 0; }
body { font-family: 'Helvetica Neue', Arial, sans-serif; background-color: var(--bg-color); color: var(--text-main); font-size: 14px; transition: background-color 0.3s, color 0.3s; }
a { text-decoration: none; color: inherit; transition: 0.2s; } a:hover { color: var(--accent-color); }

header { 
    background: var(--header-bg); 
    padding: 15px 20px; 
    display: flex; 
    align-items: center; 
    border-bottom: 2px solid var(--border-color); 
    position: sticky; 
    top: 0; 
    z-index: 1000; 
    height: 70px;
    transition: background 0.3s, border-color 0.3s;
}
.logo { font-size: 24px; font-weight: bold; text-transform: uppercase; margin-right: 30px; color: var(--text-main); } .logo span { background: var(--accent-color); padding: 2px 6px; border-radius: 4px; color: white; margin-left: 2px; }
.main-nav { display: flex; gap: 20px; flex-grow: 1; }
.main-nav a { font-weight: bold; font-size: 16px; color: var(--text-meta); } .main-nav a:hover, .main-nav a.active { color: var(--text-main); border-bottom: 2px solid var(--accent-color); }

/* Search & Toggle Area */
.header-right { display: flex; align-items: center; gap: 15px; }
.search-bar input { background: var(--input-bg); border: 1px solid var(--border-color); padding: 8px 12px; border-radius: 4px; color: var(--input-text); width: 250px; }

/* Theme Toggle Switch */
.theme-toggle { position: relative; display: inline-block; width: 50px; height: 24px; }
.theme-toggle input { opacity: 0; width: 0; height: 0; }
.slider { position: absolute; cursor: pointer; top: 0; left: 0; right: 0; bottom: 0; background-color: #ccc; transition: .4s; border-radius: 34px; display: flex; align-items: center; justify-content: space-between; padding: 0 5px; }
.slider:before { position: absolute; content: ""; height: 16px; width: 16px; left: 4px; bottom: 4px; background-color: white; transition: .4s; border-radius: 50%; z-index: 2; }
input:checked + .slider { background-color: #2196F3; }
input:checked + .slider:before { transform: translateX(26px); }
.icon-moon, .icon-sun { font-size: 14px; line-height: 1; user-select: none; }

footer { text-align: center; padding: 20px; background: var(--header-bg); border-top: 2px solid var(--border-color); color: var(--text-meta); margin-top: 40px; font-size: 13px; transition: background 0.3s; }

.container { max-width: 1400px; margin: 0 auto; padding: 20px; }
.section-title { margin-bottom: 15px; border-left: 4px solid var(--accent-color); padding-left: 10px; font-size: 18px; display: flex; align-items: center; justify-content: space-between; color: var(--text-main); }
.video-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(240px, 1fr)); gap: 20px; }
.video-card { background: var(--card-bg); border-radius: 6px; overflow: hidden; transition: transform 0.2s, background 0.3s; border: 1px solid var(--border-color); }
.video-card:hover { transform: translateY(-3px); box-shadow: 0 4px 10px rgba(0,0,0,0.1); }
.thumbnail-wrapper { position: relative; padding-top: 56.25%; display: block; background: #000; }
.thumbnail-wrapper img { position: absolute; top: 0; left: 0; width: 100%; height: 100%; object-fit: cover; }
.duration-badge { position: absolute; bottom: 5px; right: 5px; background: rgba(0,0,0,0.8); color: white; padding: 2px 5px; font-size: 11px; border-radius: 3px; font-weight: bold; }
.video-info { padding: 10px; }
.video-title { font-weight: bold; font-size: 14px; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; display: block; margin-bottom: 5px; color: var(--text-main); }
.video-meta { font-size: 12px; color: var(--text-meta); display: flex; justify-content: space-between; }
.pagination { margin-top: 30px; display: flex; justify-content: center; gap: 5px; }
.pagination a, .pagination span { padding: 8px 12px; background: var(--card-bg); border: 1px solid var(--border-color); border-radius: 4px; color: var(--text-main); }
.pagination a.active { background: var(--accent-color); color: white; border-color: var(--accent-color); }

/* Fixed Sidebar Layout */
.sidebar-left { 
    position: fixed; 
    left: 0; 
    top: 70px; /* Header Höhe */
    bottom: 0; 
    width: 240px; 
    background: var(--card-bg); 
    overflow-y: auto;
    padding: 20px;
    border-right: 1px solid var(--border-color);
    z-index: 90;
    transition: background 0.3s, border-color 0.3s;
    
    /* Minimal Scrollbar Firefox */
    scrollbar-width: thin; 
    scrollbar-color: #555 var(--card-bg);
}
.sidebar-left h3 { margin-top: 0; padding-bottom: 10px; border-bottom: 1px solid var(--border-color); font-size: 16px; color: var(--accent-color); text-align: left; }

/* Minimal Scrollbar Webkit */
.sidebar-left::-webkit-scrollbar { width: 6px; }
.sidebar-left::-webkit-scrollbar-track { background: var(--card-bg); }
.sidebar-left::-webkit-scrollbar-thumb { background-color: #555; border-radius: 3px; }

.cat-list { list-style: none; padding: 0; margin: 0; }
.cat-list li a { display: block; padding: 8px 10px; color: var(--text-meta); border-radius: 4px; transition: 0.2s; font-size: 14px; text-align: left; }
.cat-list li a:hover { background: var(--hover-bg); color: var(--text-main); padding-left: 15px; }

/* Main Content Offset */
.main-layout-wrapper { display: block; }
.main-content-offset { margin-left: 240px; padding: 20px; }
.main-content-offset .container { padding: 0; margin: 0 auto; max-width: 1400px; }

.letter-header { font-size: 24px; color: var(--accent-color); margin: 30px 0 15px 0; border-bottom: 1px solid var(--border-color); padding-bottom: 5px; text-transform: uppercase; }
.cat-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(200px, 1fr)); gap: 15px; }
.cat-card { background: var(--card-bg); padding: 15px; border-radius: 6px; text-align: center; border: 1px solid var(--border-color); transition: background 0.3s; }
.cat-card:hover { background: var(--hover-bg); border-color: var(--accent-color); }
.cat-name { font-weight: bold; font-size: 16px; display: block; margin-bottom: 5px; color: var(--text-main); }
.cat-count { font-size: 12px; color: var(--text-meta); }

.player-layout { display: flex; gap: 20px; } .main-column { flex: 3; } 

/* Rechte Sidebar auf Video Page */
.sidebar-column {
    background: var(--card-bg);
    padding: 15px;
    border-radius: 6px;
    height: fit-content;
    flex: 1;
    border: 1px solid var(--border-color);
    transition: background 0.3s;
}
.sidebar-column h3 {
    margin-top: 0;
    padding-bottom: 10px;
    border-bottom: 1px solid var(--border-color);
    font-size: 16px;
    color: var(--accent-color);
}

.video-player-container { background: #000; width: 100%; position: relative; padding-top: 56.25%; margin-bottom: 15px; }
.video-player-container iframe { position: absolute; top: 0; left: 0; width: 100%; height: 100%; border: none; }
.video-details { background: var(--card-bg); padding: 15px; border-radius: 6px; border: 1px solid var(--border-color); transition: background 0.3s; }
.video-details h1 { color: var(--text-main); }

@media (max-width: 900px) { 
    .player-layout { flex-direction: column; } 
    .search-bar input { width: 150px; } header { flex-wrap: wrap; height: auto; position: static; } .main-nav { order: 3; width: 100%; margin-top: 10px; overflow-x: auto; }
    .header-right { margin-left: auto; }
    
    .sidebar-left { position: static; width: 100%; height: auto; border-right: none; border-bottom: 1px solid var(--border-color); padding: 10px; }
    .main-content-offset { margin-left: 0; padding: 10px; }
    
    .cat-list { display: flex; flex-wrap: wrap; gap: 5px; }
    .cat-list li a { background: var(--hover-bg); padding: 5px 10px; border: 1px solid var(--border-color); }
    .cat-list li a:hover { padding-left: 10px; background: var(--hover-bg); }
}