*{margin:0;padding:0;box-sizing:border-box}:root{--primary: #4f46e5;--primary-light: #6366f1;--bg: #f7f8fa;--surface: #ffffff;--text: #1e293b;--text-secondary: #64748b;--border: #e5e7eb;--user-bg: #4f46e5;--user-text: #ffffff;--assistant-bg: #ffffff;--assistant-text: #1e293b;--code-bg: #f1f5f9}body{font-family:-apple-system,BlinkMacSystemFont,Segoe UI,PingFang SC,Hiragino Sans GB,Microsoft YaHei,sans-serif;background:var(--bg);color:var(--text);height:100vh;overflow:hidden}.chat-app{display:flex;flex-direction:column;height:100vh;max-width:80%;margin:0 auto;background:var(--surface);box-shadow:0 0 40px #0000000f}.chat-header{display:flex;align-items:center;gap:10px;padding:14px 28px;border-bottom:1px solid var(--border);background:var(--surface);flex-shrink:0}.header-icon{font-size:30px}.chat-header h1{font-size:22px;font-weight:700;color:var(--text)}.header-sub{font-size:15px;color:var(--text-secondary);margin-left:4px}.chat-messages{flex:1;overflow-y:auto;padding:24px 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