:root{--navy:#0a2540;--navy-2:#0d2f52;--gold:#f5a623;--in-bubble:#ffffff;--in-text:#0a1628;--out-bubble:#95ec69;--out-text:#0a2513;--bg:#ededed;--muted:#8a96a3;--line:rgba(0,0,0,0.06)}*{box-sizing:border-box;margin:0;padding:0;-webkit-tap-highlight-color:transparent}body,html{height:100%}body{font-family:-apple-system,BlinkMacSystemFont,PingFang SC,Microsoft YaHei,Segoe UI,Roboto,sans-serif;background:var(--bg);color:var(--in-text);-webkit-font-smoothing:antialiased;overscroll-behavior-y:none}button,input,textarea{font-family:inherit}img,video{max-width:100%}.chat-shell{position:relative;height:100dvh;display:flex;flex-direction:column;background:var(--bg);max-width:640px;margin:0 auto}@media (min-width:900px){body{background:radial-gradient(1200px 600px at 80% -10%,#14406e 0,var(--navy) 55%,#071a30 100%)}.chat-shell{max-width:760px;height:calc(100dvh - 56px);margin:28px auto;border-radius:20px;overflow:hidden;box-shadow:0 34px 90px rgba(3,12,24,.55)}.mobile-hint{display:none}}