:root{--color-background: #ffffff;--color-foreground: #0f172a;--color-muted: #f1f5f9;--color-muted-foreground: #475569;--color-border: #e2e8f0;--color-primary: #0066ff;--color-primary-hover: #0052cc;--color-destructive: #dc2626;--header-height: 48px;--input-min-height: 44px;--safe-area-inset-bottom: env(safe-area-inset-bottom, 0px)}*,*:before,*:after{box-sizing:border-box;margin:0;padding:0}html{font-size:16px;-webkit-text-size-adjust:100%}body{min-height:100vh;font-family:-apple-system,BlinkMacSystemFont,PingFang SC,Helvetica Neue,sans-serif;color:var(--color-foreground);background-color:var(--color-background);line-height:1.5}#app{min-height:100vh}@media(min-width:1024px){.chat-container{max-width:900px;margin-left:auto;margin-right:auto}}@media(max-width:767px){:root{--header-height: 44px}}