:root{--bg:#e9eef3;--panel:#fff;--ink:#14213d;--muted:#5b6b80;--line:#c9d3de;--accent:#2b59ff;--on-accent:#fff;--err:#b4440a;--sans:"IBM Plex Sans",system-ui,sans-serif;--mono:"IBM Plex Mono",ui-monospace,Consolas,monospace}
@media (prefers-color-scheme:dark){:root{--bg:#101826;--panel:#17212f;--ink:#e6edf5;--muted:#93a4b8;--line:#2a3a4f;--accent:#7b9bff;--on-accent:#0b1220;--err:#f0935a}}
*{box-sizing:border-box}
html,body{margin:0;background:var(--bg);color:var(--ink);font:15px/1.5 var(--sans)}
header{max-width:1100px;margin:0 auto;padding:28px 20px 8px}
h1{margin:0;font-size:28px;font-weight:600;letter-spacing:-.01em}
header p{margin:4px 0 0;color:var(--muted)}
.app{max-width:1100px;margin:0 auto;padding:16px 20px 40px;display:grid;grid-template-columns:200px 1fr;gap:20px}
nav{display:flex;flex-direction:column;gap:4px}
nav button{text-align:left;background:none;border:0;border-left:3px solid var(--line);padding:8px 12px;color:var(--ink);font:inherit;cursor:pointer;border-radius:0 6px 6px 0}
nav button small{display:block;color:var(--muted);font-size:13px}
nav button:hover{background:var(--panel)}
nav button[aria-current=true]{border-left-color:var(--accent);background:var(--panel);font-weight:600}
.bar{display:flex;flex-wrap:wrap;gap:10px;justify-content:space-between;align-items:center;margin-bottom:12px}
.seg,.acts{display:flex;flex-wrap:wrap;gap:6px}
.seg button{background:var(--panel);border:1px solid var(--line);color:var(--ink);padding:5px 12px;border-radius:6px;font:inherit;cursor:pointer}
.seg button[aria-pressed=true]{background:var(--accent);border-color:var(--accent);color:var(--on-accent)}
.acts button{background:none;border:1px solid var(--line);color:var(--ink);padding:5px 10px;border-radius:6px;font:inherit;cursor:pointer}
.acts button:hover:not(:disabled){border-color:var(--accent)}
.acts button:disabled{opacity:.45;cursor:default}
button:focus-visible,textarea:focus-visible{outline:2px solid var(--accent);outline-offset:2px}
.cols{display:grid;grid-template-columns:1fr 1fr;gap:14px}
.cols label{display:block;font-weight:500;margin-bottom:4px;color:var(--muted)}
textarea,pre{width:100%;height:420px;margin:0;padding:12px;background:var(--panel);border:1px solid var(--line);border-radius:8px;color:var(--ink);font:13.5px/1.55 var(--mono);overflow:auto;resize:vertical;white-space:pre-wrap;word-break:break-word}
pre.err{color:var(--err)}
@media (max-width:760px){.app{grid-template-columns:1fr}nav{flex-direction:row;overflow-x:auto}nav button{border-left:0;border-bottom:3px solid var(--line);border-radius:6px 6px 0 0;white-space:nowrap}nav button[aria-current=true]{border-bottom-color:var(--accent)}nav small{display:none}.cols{grid-template-columns:1fr}textarea,pre{height:260px}}