:root {
  --bg-main: #090d16;
  --bg-card: #131c31;
  --bg-dark: #05080e;
  --accent: #2563eb;
  --accent-hover: #1d4ed8;
  --danger: #dc2626;
  --success: #059669;
  --text: #f3f4f6;
  --text-muted: #9ca3af;
  --border: #1e293b;
}

* { box-sizing: border-box; margin: 0; padding: 0; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif; }
body { background-color: var(--bg-main); color: var(--text); height: 100vh; display: flex; flex-direction: column; overflow: hidden; }

/* Lobby Screen */
#lobby-screen { position: fixed; inset: 0; background: radial-gradient(circle at center, #131c31 0%, #090d16 100%); z-index: 1000; display: flex; justify-content: center; align-items: center; }
.lobby-card { background: var(--bg-card); border: 1px solid var(--border); padding: 40px; border-radius: 24px; width: 440px; box-shadow: 0 25px 60px rgba(0,0,0,0.6); display: flex; flex-direction: column; gap: 20px; text-align: center; }
.lobby-card h1 { font-size: 2rem; color: var(--text); display: flex; align-items: center; justify-content: center; gap: 10px; }
.lobby-card h1 span { color: var(--accent); }
.lobby-card p { color: var(--text-muted); font-size: 0.9rem; line-height: 1.5; }
.input-group { display: flex; flex-direction: column; gap: 8px; text-align: left; }
.input-group label { font-size: 0.75rem; font-weight: 700; color: var(--text-muted); text-transform: uppercase; letter-spacing: 0.05em; }
.text-input { background: var(--bg-main); border: 1px solid var(--border); color: white; padding: 12px 16px; border-radius: 12px; font-size: 1rem; outline: none; transition: 0.2s; }
.text-input:focus { border-color: var(--accent); box-shadow: 0 0 0 3px rgba(37,99,235,0.2); }
.btn { background: var(--accent); color: white; border: none; padding: 14px; border-radius: 12px; font-weight: 600; cursor: pointer; font-size: 1rem; transition: 0.2s; display: flex; align-items: center; justify-content: center; gap: 8px; }
.btn:hover { background: var(--accent-hover); transform: translateY(-1px); }
.btn-danger { background: var(--danger); }
.btn-danger:hover { background: #b91c1c; }

/* Main App Interface */
#app-container { display: none; flex-direction: column; height: 100vh; }
header { height: 64px; background: var(--bg-card); border-bottom: 1px solid var(--border); display: flex; justify-content: space-between; align-items: center; padding: 0 24px; }
.room-badge { background: var(--bg-main); border: 1px solid var(--border); padding: 8px 16px; border-radius: 30px; font-size: 0.85rem; display: flex; align-items: center; gap: 10px; color: var(--text-muted); }
.room-badge strong { color: var(--accent); }

.main-workspace { display: flex; flex: 1; height: calc(100vh - 134px); overflow: hidden; position: relative; }

/* Dynamic Multi-Party Video Grid */
.video-grid { flex: 1; display: grid; grid-template-columns: repeat(auto-fit, minmax(320px, 1fr)); gap: 16px; padding: 20px; background: var(--bg-dark); align-content: center; justify-content: center; overflow-y: auto; }
.video-box { position: relative; background: var(--bg-card); border-radius: 18px; overflow: hidden; border: 1px solid var(--border); display: flex; justify-content: center; align-items: center; min-height: 240px; aspect-ratio: 16/9; box-shadow: 0 10px 30px rgba(0,0,0,0.3); }
.video-box.screen-share-active { grid-column: span 2; grid-row: span 2; border-color: var(--accent); }
video { width: 100%; height: 100%; object-fit: cover; }
.local-mirrored { transform: scaleX(-1); }
.video-label { position: absolute; bottom: 12px; left: 12px; background: rgba(15, 23, 42, 0.75); backdrop-filter: blur(8px); padding: 6px 12px; border-radius: 10px; font-size: 0.8rem; font-weight: 500; display: flex; align-items: center; gap: 8px; border: 1px solid rgba(255,255,255,0.05); }
.status-dot { width: 8px; height: 8px; background: var(--success); border-radius: 50%; }

/* Side Panel */
.side-panel { width: 400px; background: var(--bg-card); border-left: 1px solid var(--border); display: flex; flex-direction: column; transition: 0.3s; }
.panel-tabs { display: flex; background: var(--bg-dark); border-bottom: 1px solid var(--border); }
.tab-btn { flex: 1; padding: 16px; background: none; border: none; color: var(--text-muted); font-weight: 600; font-size: 0.85rem; cursor: pointer; transition: 0.2s; border-bottom: 2px solid transparent; }
.tab-btn.active { color: var(--accent); border-bottom-color: var(--accent); background: var(--bg-card); }
.tab-content { display: none; flex: 1; flex-direction: column; overflow: hidden; }
.tab-content.active { display: flex; }

/* Chat Section */
.chat-messages { flex: 1; overflow-y: auto; padding: 16px; display: flex; flex-direction: column; gap: 12px; }
.chat-msg { background: var(--bg-main); padding: 12px 16px; border-radius: 12px; font-size: 0.85rem; line-height: 1.4; border: 1px solid var(--border); max-width: 90%; }
.chat-msg.self { background: rgba(37,99,235,0.2); border-color: rgba(37,99,235,0.4); align-self: flex-end; }
.chat-input-bar { padding: 16px; border-top: 1px solid var(--border); display: flex; gap: 8px; background: var(--bg-card); }

/* AI Assistant Section */
.ai-chat-box { flex: 1; overflow-y: auto; padding: 16px; display: flex; flex-direction: column; gap: 12px; }
.ai-msg { background: var(--bg-main); padding: 12px 16px; border-radius: 12px; font-size: 0.85rem; line-height: 1.4; border: 1px solid var(--border); }
.ai-msg.assistant { border-left: 3px solid var(--accent); }
.ai-input-bar { padding: 16px; border-top: 1px solid var(--border); display: flex; flex-direction: column; gap: 10px; background: var(--bg-card); }
.ai-controls { display: flex; justify-content: space-between; align-items: center; }

/* Bottom Control Bar */
.control-bar { height: 70px; background: var(--bg-card); border-top: 1px solid var(--border); display: flex; justify-content: center; align-items: center; gap: 16px; }
.control-btn { background: var(--bg-main); border: 1px solid var(--border); color: var(--text); width: 48px; height: 48px; border-radius: 50%; display: flex; justify-content: center; align-items: center; cursor: pointer; transition: 0.2s; font-size: 1.1rem; }
.control-btn:hover { background: var(--border); transform: scale(1.05); }
.control-btn.active-off { background: var(--danger); border-color: var(--danger); color: white; }

/* Toast Notification */
#toast { position: fixed; bottom: 30px; left: 50%; transform: translateX(-50%) translateY(100px); background: var(--success); color: white; padding: 12px 24px; border-radius: 30px; font-weight: 600; box-shadow: 0 10px 25px rgba(0,0,0,0.4); transition: 0.3s; z-index: 2000; opacity: 0; }
#toast.show { transform: translateX(-50%) translateY(0); opacity: 1; }