:root {
    /* DEFAULT DARK THEME COLORS */
    --primary: #8b5cf6;       /* Purple (For accents, buttons, tabs) */
    --accent: #22c55e;        /* Green (For 'Done' progress) */
    --bg-color: #09090b;      /* Deep Dark Background */
    --card-bg: #18181b;       /* Card Background */
    --text-main: #ffffff;     /* White Text */
    --text-sub: #a1a1aa;      /* Gray Text (Subtle text) */
    --border: #27272a;        /* Border Color */
    --shadow: 0 4px 12px rgba(0,0,0,0.3);
    --gradient: linear-gradient(135deg, #6366f1 0%, #8b5cf6 100%);
}

[data-theme="light"] {
    --bg-color: #f4f6f8;
    --card-bg: #ffffff;
    --text-main: #333333;
    --text-sub: #666666;
    --border: #e0e0e0;
    --shadow: 0 4px 12px rgba(0,0,0,0.05);
}

* { 
    margin: 0; 
    padding: 0; 
    box-sizing: border-box; 
    font-family: 'Poppins', sans-serif; 
}

body {
    background-color: var(--bg-color);
    color: var(--text-main);
    transition: background-color 0.3s;
    overflow-x: hidden;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

#particles-js { position: fixed; width: 100%; height: 100%; top: 0; left: 0; z-index: -1; opacity: 0.5; pointer-events: none; }

/* HEADER */
header { background: var(--card-bg); padding: 15px 0 0 0; text-align: center; position: sticky; top: 0; z-index: 100; border-bottom: 1px solid var(--border); box-shadow: var(--shadow); }
.header-top { display: flex; justify-content: space-between; align-items: center; padding: 0 30px; margin-bottom: 15px; }
.logo-container { display: flex; align-items: center; gap: 10px; cursor: pointer; }
#brand-title { font-size: 1.8rem; font-weight: 800; letter-spacing: 1px; background: linear-gradient(45deg, #ff0000, #ff7300, #fffb00, #48ff00, #00ffd5, #002bff, #7a00ff, #ff00c8, #ff0000); background-size: 400%; -webkit-background-clip: text; -webkit-text-fill-color: transparent; animation: rainbow 10s linear infinite; }
@keyframes rainbow { 0%{background-position:0% 50%} 50%{background-position:100% 50%} 100%{background-position:0% 50%} }

.theme-btn { background: transparent; border: 1px solid var(--border); color: var(--text-main); padding: 8px 15px; border-radius: 20px; cursor: pointer; display: flex; align-items: center; gap: 8px; transition: 0.3s; }
.theme-btn:hover { background: var(--border); }

/* SEARCH */
.search-container { max-width: 600px; margin: 0 auto 20px; padding: 0 20px; width: 100%; }
.search-box { display: flex; align-items: center; background: var(--bg-color); border-radius: 12px; padding: 12px 20px; border: 1px solid var(--border); transition: 0.3s; }
.search-box:focus-within { border-color: var(--primary); box-shadow: 0 0 0 2px rgba(139, 92, 246, 0.2); }
.search-box input { border: none; background: transparent; outline: none; width: 100%; margin-left: 10px; color: var(--text-main); font-size: 1rem; }
.header-border { height: 3px; background: linear-gradient(90deg, var(--primary), var(--accent)); width: 100%; }

/* NAV */
#nav-controls { padding: 20px 30px; display: flex; align-items: center; gap: 15px; max-width: 1200px; margin: 0 auto; width: 100%; }
#back-btn { background: var(--card-bg); border: 1px solid var(--border); color: var(--text-main); padding: 8px 16px; border-radius: 8px; cursor: pointer; display: flex; align-items: center; gap: 5px; transition: 0.2s; }
#back-btn:hover { border-color: var(--primary); color: var(--primary); }
#current-path { color: var(--text-sub); font-size: 0.9rem; font-weight: 500; text-transform: uppercase; letter-spacing: 0.5px; }
.hidden { display: none !important; }

/* MAIN CONTENT */
#main-content { max-width: 1200px; margin: 0 auto; padding: 20px 30px; width: 100%; flex: 1; }
.grid-layout { display: grid; grid-template-columns: repeat(auto-fill, minmax(300px, 1fr)); gap: 25px; padding-bottom: 50px; }

/* CARDS (Home) */
.card { background: var(--card-bg); border: 1px solid var(--border); border-radius: 16px; overflow: hidden; transition: transform 0.2s; cursor: pointer; display: flex; flex-direction: column; }
.card:hover { transform: translateY(-5px); border-color: var(--primary); box-shadow: 0 10px 30px rgba(0,0,0,0.3); }
.card-img { height: 160px; background: #202020; display: flex; align-items: center; justify-content: center; border-bottom: 1px solid var(--border); }
.card-body { padding: 20px; }
.card-title { font-size: 1.2rem; font-weight: 700; margin-bottom: 5px; color: var(--text-main); }
.card-meta { font-size: 0.9rem; color: var(--text-sub); }

/* --- BATCH TABS (Reused for Chapters Tabs) --- */
.batch-tabs { display: flex; gap: 25px; margin-bottom: 25px; border-bottom: 1px solid var(--border); }
.batch-tab { background: none; border: none; color: var(--text-sub); padding: 12px 5px; font-size: 1.05rem; font-weight: 500; cursor: pointer; position: relative; transition: 0.3s; }
.batch-tab:hover { color: var(--text-main); }
.batch-tab.active { color: var(--primary); font-weight: 600; }
.batch-tab.active::after { content: ''; position: absolute; bottom: -1px; left: 0; width: 100%; height: 3px; background: var(--primary); border-radius: 3px 3px 0 0; }

/* --- SUBJECT LIST CARD DESIGN (Like Screenshot 160050.png) --- */
.subject-card-list { display: flex; align-items: center; background: var(--card-bg); border: 1px solid var(--border); border-radius: 12px; padding: 20px 25px; margin-bottom: 15px; cursor: pointer; transition: 0.2s; }
.subject-card-list:hover { transform: translateY(-3px); border-color: var(--primary); }
.sub-icon-box { width: 55px; height: 55px; border-radius: 12px; background: #fff; color: #333; display: flex; align-items: center; justify-content: center; font-weight: 800; font-size: 1.3rem; margin-right: 20px; flex-shrink: 0; }
.sub-info { flex-grow: 1; }
.sub-title { font-size: 1.1rem; font-weight: 700; color: var(--text-main); margin-bottom: 4px; }
.sub-meta { font-size: 0.85rem; color: var(--text-sub); }
.sub-progress { width: 150px; text-align: right; margin-left: 20px; flex-shrink: 0; }
.prog-text { display: block; font-size: 0.85rem; font-weight: 700; color: var(--accent); margin-bottom: 6px; }
.prog-bg { width: 100%; height: 6px; background: var(--border); border-radius: 10px; overflow: hidden; }
.prog-fill { height: 100%; background: var(--accent); border-radius: 10px; }

/* CHAPTER CARD */
.chapter-card { height: auto; min-height: 140px; justify-content: space-between; }
.chapter-tag { font-size: 0.75rem; font-weight: 700; color: var(--primary); text-transform: uppercase; margin-bottom: 8px; letter-spacing: 0.5px; background: rgba(139, 92, 246, 0.1); display: inline-block; padding: 3px 8px; border-radius: 4px; }
.lecture-status { font-size: 0.85rem; color: var(--text-sub); padding-top: 10px; border-top: 1px solid var(--border); margin-top: 10px; }

/* --- PLAYER & RESOURCES --- */
.chapter-container { display: flex; gap: 20px; height: calc(100vh - 140px); overflow: hidden; }
.chapter-sidebar { width: 320px; background: var(--card-bg); border: 1px solid var(--border); border-radius: 12px; display: flex; flex-direction: column; height: 100%; flex-shrink: 0; }
.sidebar-header { padding: 15px; font-weight: 700; border-bottom: 1px solid var(--border); background: var(--bg-color); }
.sidebar-list { overflow-y: auto; flex: 1; padding: 10px; }
.chapter-list-item { padding: 12px 15px; margin-bottom: 5px; border-radius: 8px; cursor: pointer; font-size: 0.9rem; color: var(--text-sub); transition: 0.2s; border-left: 3px solid transparent; }
.chapter-list-item.active { background: rgba(139, 92, 246, 0.1); color: var(--primary); border-left-color: var(--primary); }

.chapter-content-area { flex: 1; background: var(--card-bg); border: 1px solid var(--border); border-radius: 12px; display: flex; flex-direction: column; overflow: hidden; }
.content-header { padding: 0 20px; border-bottom: 1px solid var(--border); background: var(--bg-color); }
.tabs { display: flex; gap: 25px; margin-bottom: 0; border: none; }
.tab { padding: 15px 5px; cursor: pointer; color: var(--text-sub); font-weight: 500; position: relative; }
.tab.active { color: var(--primary); }
.tab.active::after { content: ''; position: absolute; bottom: 0; left: 0; width: 100%; height: 3px; background: var(--primary); }
#content-list-container { padding: 20px; overflow-y: auto; flex: 1; }

.resource-item { display: flex; justify-content: space-between; align-items: center; background: var(--card-bg); padding: 15px 20px; border-radius: 10px; border: 1px solid var(--border); margin-bottom: 10px; transition: 0.2s; }
.resource-item:hover { border-color: var(--text-sub); transform: translateX(3px); }
.res-left { display: flex; align-items: center; gap: 15px; }
.btn-small { padding: 6px 12px; border-radius: 6px; font-size: 0.85rem; cursor: pointer; border: 1px solid var(--border); background: var(--bg-color); color: var(--text-main); }
.play-btn { background: var(--primary); border: none; color: white; }

/* --- VIDEO PLAYER MODAL FIXES --- */

#video-player-modal { 
    position: fixed; top: 0; left: 0; width: 100%; height: 100%; 
    background: #000; z-index: 5000; 
    overflow-y: auto; 
    display: flex; 
    flex-direction: column; 
}
.vp-header { padding: 15px 20px; border-bottom: 1px solid #333; display: flex; justify-content: space-between; align-items: center; background: #111; }
.vp-body { 
    flex: 1; 
    display: flex; 
    flex-direction: column; /* Stack video and info vertically */
    overflow-y: auto; 
    height: 100%; 
}
.vp-video-container { 
    width: 100%; 
    max-width: 1000px;
    margin: 0 auto; 
    padding: 30px; 
    flex-shrink: 0; /* Important for preventing video container from shrinking */
    display: flex;
    flex-direction: column;
    align-items: center;
}
.video-wrapper { 
    width: 100%; 
    aspect-ratio: 16/9; 
    background: #000; 
    border-radius: 12px; 
    overflow: hidden; 
    box-shadow: 0 0 30px rgba(0,0,0,0.5); 
}
.vp-info { 
    max-width: 1000px; 
    width: 100%; 
    margin: 0 auto; 
    padding: 0 30px 30px; /* Padding for the quotes/info section */
}
.vp-sidebar { width: 320px; background: #111; border-left: 1px solid #333; display: flex; flex-direction: column; }

/* --- QUOTE BRACKET EFFECT CSS --- */

.vp-info .vp-quote {
    /* Base styles */
    margin-top: 25px;
    font-style: italic;
    color: var(--text-sub); 
    font-size: 1rem; 
    line-height: 1.6;
    padding: 10px 0;
    position: relative;
    padding-left: 25px; 
}

.vp-info .vp-quote.purple-bracket {
    /* 1. Vertical Line */
    border-left: 3px solid var(--primary); 
    padding-top: 20px; 
    padding-bottom: 20px; 
    color: var(--text-main); 
}

/* 2. Horizontal Corner Brackets */
.vp-info .vp-quote.purple-bracket::before,
.vp-info .vp-quote.purple-bracket::after {
    content: '';
    position: absolute;
    left: 0;
    width: 15px; 
    height: 3px;
    background: var(--primary);
}

.vp-info .vp-quote.purple-bracket::before { top: 0; }
.vp-info .vp-quote.purple-bracket::after { bottom: 0; }


/* ASK DOUBT BUTTON (Fixed) */
.fab-doubt { position: fixed; bottom: 30px; right: 30px; background: var(--gradient); color: white; border: none; padding: 12px 25px; border-radius: 50px; font-weight: 600; cursor: pointer; box-shadow: 0 5px 20px rgba(99, 102, 241, 0.5); display: flex; align-items: center; gap: 10px; z-index: 10000; font-size: 1rem; }
.fab-doubt:hover { transform: scale(1.05); }

/* Footer */
footer { text-align: center; padding: 30px; color: var(--text-sub); border-top: 1px solid var(--border); margin-top: auto; background: var(--card-bg); }
.empty-state { text-align: center; padding: 50px; color: var(--text-sub); }

/* Mobile */
@media (max-width: 768px) {
    .vp-body { flex-direction: column; }
    .vp-sidebar { width: 100%; height: auto; border-left: none; border-top: 1px solid #333; }
    .chapter-container { flex-direction: column; height: auto; }
    .chapter-sidebar { display: none; }
    .subject-card-list { flex-direction: column; align-items: flex-start; }
    .sub-icon-box { margin-bottom: 15px; }
    .sub-progress { width: 100%; margin-left: 0; margin-top: 15px; text-align: left; }
}