:root{--primary: #ff4b4b;--bg-color: #ffffff;--text-color: #31333f;--secondary-bg: #f0f2f6;--border-color: #e0e0e0;--font-family: "Source Sans Pro", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;--radius: .5rem;--shadow: 0 4px 6px -1px rgba(0, 0, 0, .1), 0 2px 4px -1px rgba(0, 0, 0, .06)}@media(prefers-color-scheme:dark){:root{--bg-color: #0e1117;--text-color: #fafafa;--secondary-bg: #262730;--border-color: #41424b}}*{box-sizing:border-box;margin:0;padding:0}body{font-family:var(--font-family);background-color:var(--bg-color);color:var(--text-color);line-height:1.6}#root{display:flex;flex-direction:column;min-height:100vh}.container{max-width:800px;margin:0 auto;padding:2rem;width:100%}.header{margin-bottom:2rem;text-align:center}.header h1{font-weight:700;font-size:2.5rem}.card{background:var(--bg-color);border:1px solid var(--border-color);border-radius:var(--radius);padding:2rem;box-shadow:var(--shadow)}.btn{background-color:var(--primary);color:#fff;border:none;padding:.5rem 1rem;border-radius:var(--radius);cursor:pointer;font-weight:600;font-size:1rem;transition:opacity .2s}.btn:hover{opacity:.8}.input-group{display:flex;gap:.5rem}.input-field{flex:1;padding:.75rem;border:1px solid var(--border-color);border-radius:var(--radius);background:var(--secondary-bg);color:var(--text-color);font-size:1rem}.input-field:focus{outline:2px solid var(--primary);border-color:transparent}.message{margin-bottom:1rem;padding:1rem;border-radius:var(--radius);max-width:85%}.message.user{background-color:var(--secondary-bg);margin-left:auto;border-top-right-radius:0}.message.assistant{background-color:transparent;border:1px solid var(--border-color);margin-right:auto;border-top-left-radius:0}.message-icon{margin-right:.5rem;display:inline-flex;align-items:center;justify-content:center;width:2rem;height:2rem;background:#eee;border-radius:50%}.upload-area{border:2px dashed var(--border-color);border-radius:var(--radius);padding:3rem;text-align:center;cursor:pointer;background:var(--secondary-bg);transition:border-color .2s;display:flex;flex-direction:column;align-items:center;justify-content:center}.upload-area:hover{border-color:var(--primary)}.app-layout{display:flex;width:100vw;height:100vh;overflow:hidden;position:relative}.main-content{flex:1;position:relative;display:flex;flex-direction:column;height:100%;overflow:hidden}.sidebar{width:260px;height:100vh;background-color:var(--secondary-bg);color:var(--text-color);display:flex;flex-direction:column;border-right:1px solid var(--border-color);transition:transform .3s ease;z-index:1000}.sidebar-header{padding:1rem}.new-chat-btn{width:100%;padding:.75rem;border-radius:var(--radius);border:1px solid var(--border-color);background:transparent;color:inherit;display:flex;align-items:center;justify-content:center;gap:.5rem;cursor:pointer;transition:background .2s;font-family:inherit}.new-chat-btn:hover{background:var(--border-color)}.sidebar-list{flex:1;overflow-y:auto;padding:0 .5rem}.sidebar-item{padding:.75rem;margin:.25rem 0;border-radius:var(--radius);cursor:pointer;display:flex;align-items:center;gap:.5rem;font-size:.9rem;position:relative;color:#888;transition:background .2s,color .2s}.sidebar-item:hover,.sidebar-item.active{background:var(--border-color);color:var(--text-color)}.sidebar-item-title{flex:1;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}.delete-btn{background:transparent;border:none;color:#ff4b4b;cursor:pointer;padding:.25rem;display:none}.sidebar-item:hover .delete-btn{display:block}.mobile-header{display:none;padding:1rem;border-bottom:1px solid var(--border-color);align-items:center;gap:1rem;background:var(--bg-color)}.menu-btn{background:transparent;border:none;cursor:pointer;color:var(--text-color);padding:.5rem}.sidebar-overlay{display:none}.chat-container{display:flex;flex-direction:column;height:100%;max-width:900px;margin:0 auto;width:100%;padding:1rem}.chat-header{padding-bottom:1rem;margin-bottom:1rem;border-bottom:1px solid var(--border-color);display:flex;justify-content:space-between;align-items:center}.chat-messages{flex:1;overflow-y:auto;margin-bottom:1rem;padding-right:.5rem;scroll-behavior:smooth}.upload-center{display:flex;align-items:center;justify-content:center;height:100%;padding:1rem}@media(max-width:768px){.app-layout{flex-direction:column}.sidebar{position:fixed;left:0;top:0;bottom:0;transform:translate(-100%);background:var(--bg-color);width:80%;max-width:300px;box-shadow:2px 0 10px #0003}.sidebar.open{transform:translate(0)}.sidebar-overlay{display:block;position:fixed;inset:0;background:#00000080;z-index:999;opacity:0;pointer-events:none;transition:opacity .3s}.sidebar-overlay.visible{opacity:1;pointer-events:auto}.mobile-header{display:flex}.chat-container{padding:.5rem}.message{max-width:95%}.card{padding:1rem;width:100%;max-width:100%}.upload-area{padding:1.5rem}}