:root{--bg: #f4f6f9;--card-bg: #ffffff;--text: #1f2733;--text-muted: #7a8699;--accent: #4f7cff;--accent-hover: #3d68e8;--accent-soft: #eaf0ff;--danger: #e5484d;--danger-soft: #fdecec;--border: #e3e8ef;--radius: 14px;--shadow: 0 4px 24px rgba(31, 39, 51, .07)}:root[data-theme=dark]{--bg: #10141b;--card-bg: #1a212c;--text: #e8ecf3;--text-muted: #8b96a8;--accent: #5b84ff;--accent-hover: #7396ff;--accent-soft: #223055;--danger: #ff6b70;--danger-soft: #3a2327;--border: #2a3342;--shadow: 0 4px 24px rgba(0, 0, 0, .4)}*{box-sizing:border-box}body{margin:0;font-family:Inter,system-ui,-apple-system,Segoe UI,sans-serif;background:var(--bg);color:var(--text);transition:background .25s ease,color .25s ease}.app{min-height:100vh;display:flex;flex-direction:column}.header{display:flex;justify-content:space-between;align-items:center;padding:14px 24px;background:var(--card-bg);border-bottom:1px solid var(--border)}.logo{border:none;background:transparent;padding:0;font-family:inherit;color:var(--text);font-weight:700;font-size:18px;cursor:pointer;transition:opacity .15s ease}.logo:hover{opacity:.75}.header-right{display:flex;align-items:center;gap:14px}.online{display:flex;align-items:center;gap:7px;font-size:14px;color:var(--text-muted)}.theme-toggle{border:1.5px solid var(--border);background:var(--card-bg);border-radius:10px;padding:6px 10px;font-size:16px;line-height:1;cursor:pointer;transition:border-color .15s ease,transform .15s ease}.theme-toggle:hover{border-color:var(--accent);transform:scale(1.06)}.online-dot{width:9px;height:9px;border-radius:50%;background:#34c759;box-shadow:0 0 0 3px #34c7592e}.main{flex:1;display:flex;justify-content:center;align-items:flex-start;padding:32px 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ease}.text-input:focus{border-color:var(--accent)}.topic-answer-input{margin-top:8px}.hint{margin:8px 0 0}.topic-form-actions{display:flex;gap:10px;margin-top:4px}.topic-form-actions .btn-primary{flex:1}.btn{border:none;border-radius:10px;padding:12px 20px;font-size:15px;font-weight:600;font-family:inherit;cursor:pointer;transition:all .15s ease}.btn:disabled{opacity:.45;cursor:default}.btn-primary{background:var(--accent);color:#fff}.btn-primary:hover:not(:disabled){background:var(--accent-hover)}.btn-secondary{background:var(--bg);color:var(--text);border:1.5px solid var(--border)}.btn-secondary:hover{border-color:var(--text-muted)}.btn-danger{background:var(--danger-soft);color:var(--danger)}.btn-danger:hover{background:var(--danger);color:#fff}.btn-sm{padding:8px 14px;font-size:13px}.btn-search{width:100%;margin-top:8px;padding:15px;font-size:16px}.search-card{text-align:center;padding:48px 28px}.search-card h2{margin:20px 0 6px}.search-card 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14px;font-size:12px;color:var(--text-muted);border-bottom:1px solid var(--border)}.global-chat-messages{flex:1;overflow-y:auto;padding:10px 14px;display:flex;flex-direction:column;gap:7px}.global-chat-empty{margin:auto;text-align:center;font-size:13px;color:var(--text-muted)}.gmsg{font-size:13.5px;line-height:1.45;word-break:break-word}.gmsg-me{background:var(--accent-soft);border-radius:8px;padding:3px 8px;margin:0 -8px}.gmsg-author{font-weight:700;margin-right:6px}.gmsg-author:after{content:":";color:var(--text-muted)}.gmsg-time{margin-left:6px;font-size:10.5px;color:var(--text-muted)}.global-chat-input-row{display:flex;gap:8px;padding:10px 12px;border-top:1px solid var(--border)}.global-chat-input{flex:1;min-width:0;padding:9px 12px;border:1.5px solid var(--border);border-radius:9px;font-size:14px;font-family:inherit;background:var(--card-bg);color:var(--text);outline:none;transition:border-color .15s ease}.global-chat-input:focus{border-color:var(--accent)}@media(max-width:600px){.main{padding:12px}.card{padding:20px}.chat-card{height:calc(100vh - 150px);padding:0}.msg-bubble{max-width:85%}.global-chat{left:0!important;right:0!important;top:auto!important;bottom:0!important;width:100%!important;height:55vh;border-radius:var(--radius) var(--radius) 0 0;border-left:none;border-right:none;border-bottom:none}.global-chat-header{cursor:default}.global-chat-fab{right:14px;bottom:14px}}