body{margin:0;font:16px system-ui,sans-serif;background:#10141d;color:#eee}main{max-width:1200px;margin:auto;padding:24px}header,nav,.checkpoint-controls{display:flex;gap:12px;align-items:center;flex-wrap:wrap}header h1{margin-right:auto}nav{margin:24px 0}button,a{padding:8px 14px;border-radius:6px;color:inherit}button{background:#28364c;border:1px solid #50607a;cursor:pointer;text-align:left}button:disabled{opacity:.5;cursor:default}button[aria-current],button[aria-pressed=true]{border-color:#9fc4ff;background:#344c70}input,select,textarea{box-sizing:border-box;background:#202839;color:inherit;border:1px solid #50607a;padding:10px;border-radius:4px;max-width:100%}input,textarea{display:block;width:100%;margin:8px 0}textarea{min-height:100px}pre{white-space:pre-wrap;overflow-wrap:anywhere;font:inherit;line-height:1.55}article{padding:12px;border-bottom:1px solid #344052}[role=alert]{color:#ffb7b7}[role=status]{min-height:1.5em;color:#bad5ff}.chat-layout{display:grid;grid-template-columns:250px minmax(0,1fr);gap:24px}.history{display:flex;flex-direction:column;gap:8px;margin:16px 0}.history button{overflow-wrap:anywhere}.chat-content{min-width:0}.checkpoint-controls select{display:block;margin:8px 0}.preview-note{padding:12px;background:#253247}aside>label{display:block;margin-top:18px}@media(max-width:700px){main{padding:16px}.chat-layout{grid-template-columns:1fr}.history{max-height:180px;overflow:auto}header h1{font-size:1.4rem}}