*,:before,:after{box-sizing:border-box;margin:0;padding:0}:root{--color-bg:#f5f5f7;--color-surface:#fff;--color-surface-secondary:#f5f5f7;--color-border:#e5e5ea;--color-text-primary:#1d1d1f;--color-text-secondary:#6e6e73;--color-text-tertiary:#aeaeb2;--color-accent:#0071e3;--color-accent-hover:#0077ed;--color-accent-light:#e8f2ff;--color-error:#d93025;--color-error-light:#fce8e6;--color-warning:#92400e;--color-warning-light:#fef3c7;--color-success:#065f46;--color-success-light:#d1fae5;--color-user-bubble:#0071e3;--color-assistant-bubble:#f5f5f7;--radius-sm:8px;--radius-md:12px;--radius-lg:16px;--font-sans:-apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;--font-mono:"SF Mono", "Fira Code", "Consolas", monospace;--shadow-sm:0 1px 4px #0000000f;--shadow-md:0 2px 16px #00000014}html,body{height:100%;font-family:var(--font-sans);background:var(--color-bg);color:var(--color-text-primary);-webkit-font-smoothing:antialiased;font-size:15px;line-height:1.5}#root,.app{flex-direction:column;height:100%;display:flex}.app-header{background:var(--color-surface);border-bottom:1px solid var(--color-border);z-index:10;flex-shrink:0;align-items:center;gap:12px;height:52px;padding:0 20px;display:flex;position:sticky;top:0}.app-header__logo{color:var(--color-text-primary);letter-spacing:-.02em;font-size:1rem;font-weight:700}.app-header__spacer{flex:1}.app-body{flex:1;display:flex;overflow:hidden}.sidebar{background:var(--color-surface);border-right:1px solid var(--color-border);flex-direction:column;flex-shrink:0;width:260px;display:flex;overflow:hidden}.sidebar__header{align-items:center;gap:8px;padding:14px 16px 10px;display:flex}.sidebar__title{text-transform:uppercase;letter-spacing:.05em;color:var(--color-text-tertiary);flex:1;font-size:.8rem;font-weight:700}.sidebar__new-btn{color:var(--color-accent);cursor:pointer;border-radius:var(--radius-sm);background:0 0;border:none;align-items:center;gap:6px;padding:4px 8px;font-size:.8rem;font-weight:500;transition:background .15s;display:flex}.sidebar__new-btn:hover{background:var(--color-accent-light)}.sidebar__list{flex:1;padding:4px 8px 16px;overflow-y:auto}.sidebar__empty{color:var(--color-text-tertiary);text-align:center;padding:24px 16px;font-size:.85rem}.sidebar__loading{color:var(--color-text-tertiary);text-align:center;padding:16px;font-size:.85rem}.session-item{border-radius:var(--radius-sm);cursor:pointer;align-items:center;gap:8px;min-width:0;padding:8px 10px;transition:background .12s;display:flex;position:relative}.session-item:hover{background:var(--color-surface-secondary)}.session-item--active{background:var(--color-accent-light)}.session-item__title{color:var(--color-text-primary);white-space:nowrap;text-overflow:ellipsis;flex:1;min-width:0;font-size:.85rem;overflow:hidden}.session-item--active .session-item__title{color:var(--color-accent);font-weight:500}.session-item__delete{opacity:0;cursor:pointer;color:var(--color-text-tertiary);background:0 0;border:none;border-radius:4px;flex-shrink:0;padding:2px 4px;font-size:1rem;line-height:1;transition:opacity .12s,color .12s,background .12s}.session-item:hover .session-item__delete{opacity:1}.session-item__delete:hover{color:var(--color-error);background:var(--color-error-light)}.chat-main{flex-direction:column;flex:1;display:flex;overflow:hidden}.message-list{flex-direction:column;flex:1;gap:4px;padding:24px 0;display:flex;overflow-y:auto}.message-list__empty{color:var(--color-text-secondary);flex-direction:column;flex:1;justify-content:center;align-items:center;gap:8px;padding:48px 24px;display:flex}.message-list__empty-icon{margin-bottom:8px;font-size:2.5rem}.message-list__empty-title{color:var(--color-text-primary);font-size:1.1rem;font-weight:600}.message-list__empty-desc{color:var(--color-text-secondary);text-align:center;max-width:300px;font-size:.875rem}.message{padding:2px 20px;display:flex}.message--user{justify-content:flex-end}.message--assistant{justify-content:flex-start}.message__bubble{border-radius:var(--radius-md);white-space:pre-wrap;word-break:break-word;max-width:72%;padding:10px 14px;font-size:.9rem;line-height:1.6}.message--user .message__bubble{background:var(--color-user-bubble);color:#fff;border-bottom-right-radius:4px}.message--assistant .message__bubble{background:var(--color-assistant-bubble);color:var(--color-text-primary);border:1px solid var(--color-border);border-bottom-left-radius:4px}.message__streaming-cursor{background:var(--color-text-secondary);vertical-align:text-bottom;width:2px;height:1em;margin-left:2px;animation:1s step-end infinite blink;display:inline-block}@keyframes blink{0%,to{opacity:1}50%{opacity:0}}.chat-input-area{background:var(--color-surface);border-top:1px solid var(--color-border);flex-shrink:0;padding:16px 20px 20px}.chat-input-form{align-items:flex-end;gap:10px;max-width:800px;margin:0 auto;display:flex}.chat-input{min-height:44px;max-height:160px;font-size:.9rem;font-family:var(--font-sans);color:var(--color-text-primary);background:var(--color-surface-secondary);border:1px solid var(--color-border);border-radius:var(--radius-md);resize:none;outline:none;flex:1;padding:10px 14px;line-height:1.5;transition:border-color .15s,box-shadow .15s}.chat-input:focus{border-color:var(--color-accent);box-shadow:0 0 0 3px 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.15s}.chat-stop-btn:hover{background:var(--color-error-light);color:var(--color-error);border-color:var(--color-error)}.model-selector{align-items:center;gap:6px;display:flex}.model-selector__label{color:var(--color-text-secondary);font-size:.8rem}.model-selector__select{font-size:.8rem;font-family:var(--font-sans);color:var(--color-text-primary);background:var(--color-surface-secondary);border:1px solid var(--color-border);cursor:pointer;border-radius:6px;outline:none;padding:4px 8px;transition:border-color .15s}.model-selector__select:focus{border-color:var(--color-accent)}.error-toast-container{z-index:100;pointer-events:none;flex-direction:column;gap:8px;width:calc(100% - 40px);max-width:560px;display:flex;position:fixed;top:60px;left:50%;transform:translate(-50%)}.error-toast{background:var(--color-surface);border:1px solid var(--color-border);border-left:4px solid 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toast-in{0%{opacity:0;transform:translateY(-8px)}to{opacity:1;transform:translateY(0)}}.btn{border-radius:var(--radius-sm);font-size:.875rem;font-weight:500;font-family:var(--font-sans);cursor:pointer;border:none;align-items:center;gap:6px;padding:8px 16px;transition:background .15s,color .15s;display:inline-flex}.btn--primary{background:var(--color-accent);color:#fff}.btn--primary:hover{background:var(--color-accent-hover)}.btn--secondary{background:var(--color-surface-secondary);color:var(--color-text-secondary);border:1px solid var(--color-border)}.btn--secondary:hover{background:var(--color-border)}.sidebar__list::-webkit-scrollbar{width:4px}.message-list::-webkit-scrollbar{width:4px}.sidebar__list::-webkit-scrollbar-track{background:0 0}.message-list::-webkit-scrollbar-track{background:0 0}.sidebar__list::-webkit-scrollbar-thumb{background:var(--color-border);border-radius:2px}.message-list::-webkit-scrollbar-thumb{background:var(--color-border);border-radius:2px}@media (width<=640px){.sidebar{display:none}.message__bubble{max-width:88%}}