:root{--primary: #1976d2;--primary-dark: #1565c0;--border: #e0e0e0}*{box-sizing:border-box}html,body{height:100%}body{margin:0;font-family:system-ui,-apple-system,Segoe UI,Roboto,Helvetica,Arial,"Apple Color Emoji","Segoe UI Emoji";color:#1f2937;background:#fff}.app-header{position:sticky;top:0;z-index:10;display:flex;align-items:center;gap:12px;padding:10px 16px;border-bottom:1px solid var(--border);background:#fafafa}.app-header .brand{font-weight:600}.app-header .spacer{flex:1}.app-header select{padding:6px 8px}.app-header .lang-label{font-size:14px;color:#374151;margin-right:4px}.app-main{padding:0 0 24px}