:root { --bg: #f6f7f9; --card: #fff; --line: #e2e5ea; --ink: #1d2330; --muted: #6b7280;
        --accent: #1f4e79; --ok: #1e7d4f; --err: #b42318; --me: #e8f0f8; }
* { box-sizing: border-box; }
[hidden] { display: none !important; }
body { margin: 0; font: 15px/1.45 system-ui, sans-serif; color: var(--ink); background: var(--bg);
       height: 100vh; display: flex; flex-direction: column; }
header { display: flex; align-items: center; gap: 12px; padding: 10px 16px; background: var(--accent); color: #fff; }
header select, header button { font: inherit; }
.brand { font-size: 18px; letter-spacing: .5px; }
.spacer { flex: 1; }
button { background: var(--accent); color: #fff; border: 0; border-radius: 6px; padding: 8px 14px; cursor: pointer; }
header button { background: rgba(255,255,255,.15); }
button:disabled { opacity: .5; cursor: default; }
.muted { color: var(--muted); }
.error { color: var(--err); }

#login { flex: 1; display: grid; place-items: center; }
#login form { background: var(--card); padding: 28px; border-radius: 10px; border: 1px solid var(--line);
              width: min(360px, 100% - 32px); display: grid; gap: 12px; }
#login h1 { margin: 0 0 4px; font-size: 20px; }
#login label { display: grid; gap: 4px; font-size: 13px; color: var(--muted); }
#login input { font: inherit; padding: 8px; border: 1px solid var(--line); border-radius: 6px; }

dialog { border: 1px solid var(--line); border-radius: 10px; padding: 24px; width: min(380px, 100% - 32px); }
dialog form { display: grid; gap: 10px; }
dialog h2 { margin: 0; font-size: 18px; }
dialog label { display: grid; gap: 4px; font-size: 13px; color: var(--muted); }
dialog input { font: inherit; padding: 8px; border: 1px solid var(--line); border-radius: 6px; }
dialog .row { display: flex; justify-content: flex-end; gap: 8px; }
button.secondary { background: var(--line); color: var(--ink); }
button.link { background: none; color: var(--accent); padding: 0; justify-self: start; text-decoration: underline; }

#app { flex: 1; display: grid; grid-template-columns: var(--chat-w, 40%) 8px 1fr; min-height: 0; }
.chat { display: flex; flex-direction: column; min-height: 0; min-width: 0; }
#splitter { cursor: col-resize; background: var(--line); border-inline: 3px solid var(--bg); touch-action: none; }
#splitter:hover, #splitter:focus-visible, body.resizing #splitter { background: var(--accent); outline: none; }
body.resizing { cursor: col-resize; user-select: none; }
body.resizing #frame { pointer-events: none; }
body.preview-full #app { grid-template-columns: 1fr; grid-template-rows: 1fr; }
body.preview-full .chat, body.preview-full #splitter { display: none; }
#feed { flex: 1; overflow-y: auto; padding: 16px; display: flex; flex-direction: column; gap: 10px; }
.msg { background: var(--card); border: 1px solid var(--line); border-radius: 10px; padding: 10px 12px;
       white-space: pre-wrap; word-wrap: break-word; }
.msg.me { background: var(--me); align-self: flex-end; max-width: 90%; }
.msg.step { font: 12px/1.4 ui-monospace, monospace; color: var(--muted); padding: 4px 10px; background: transparent; }
.msg.step.denied, .msg.step.err { color: var(--err); }
.meta { font-size: 12px; color: var(--muted); }
.status-succeeded { color: var(--ok); } .status-failed { color: var(--err); }
#ask { display: flex; gap: 8px; padding: 12px; border-top: 1px solid var(--line); background: var(--card); }
#ask textarea { flex: 1; font: inherit; padding: 8px; border: 1px solid var(--line); border-radius: 6px; resize: vertical; }

.preview { display: flex; flex-direction: column; min-height: 0; min-width: 0; }
.preview-bar { display: flex; gap: 12px; align-items: center; padding: 8px 12px; border-bottom: 1px solid var(--line); background: var(--card); }
.preview-bar button { padding: 4px 10px; }
#frame { flex: 1; border: 0; background: #fff; width: 100%; }
#no-preview { padding: 16px; }

@media (max-width: 800px) {
  #app { grid-template-columns: 1fr; grid-template-rows: 1fr 50vh; }
  .chat { border-bottom: 1px solid var(--line); }
  #splitter { display: none; }
}