:root { color-scheme: dark; font-family: system-ui, -apple-system, Segoe UI, sans-serif; background: #081225; color: #e8f1ff; }
* { box-sizing: border-box; }
body { margin: 0; min-height: 100vh; background: radial-gradient(circle at 15% 0%, #16375c 0, #081225 46%); }
.preview-shell { max-width: 850px; margin: 0 auto; padding: clamp(20px,5vw,52px) 18px 30px; }
.eyebrow { color: #83bde8; font-size: .72rem; letter-spacing: .16em; font-weight: 750; }
h1 { font-size: clamp(2rem,4vw,3.2rem); margin: .35em 0 .1em; letter-spacing: -.04em; }
.preview-heading p { color: #afc3dc; line-height: 1.55; }
.preview-heading .notice { color: #d0deef; font-size: .9rem; }
.chat-panel { border: 1px solid #3c5571; border-radius: 18px; background: #0e1d32; box-shadow: 0 18px 60px #02081477; overflow: hidden; }
.chat-scroll { min-height: 265px; height: clamp(290px,52vh,520px); overflow-y: auto; padding: 24px 18px; }
.chat-messages { display: grid; gap: 16px; }
.chat-bubble-row { display: flex; gap: 10px; align-items: flex-start; }
.user-row { justify-content: flex-end; }
.chat-msg-avatar { border: 1px solid #405a76; color: #bcd2e7; border-radius: 50%; width: 32px; height: 32px; display: grid; place-items: center; flex: none; font-size: .54rem; }
.user-row .chat-msg-avatar { order: 2; }
.chat-bubble { max-width: 88%; padding: 12px 14px; border-radius: 14px; line-height: 1.55; overflow-wrap: anywhere; white-space: pre-wrap; }
.bot-bubble { background: #152c47; border: 1px solid #314862; }
.user-bubble { background: #144d75; }
#chat-form { border-top: 1px solid #34465c; padding: 18px; }
#chat-form label { display: block; font-size: .82rem; margin-bottom: 9px; color: #c0d6ef; }
.chat-controls { display: flex; flex-wrap: wrap; gap: 9px; align-items: stretch; }
#chat-input { flex: 1; min-width: 130px; border-radius: 9px; padding: 12px; background: #0b172a; border: 1px solid #5b7998; color: #fff; font: inherit; }
button { border-radius: 9px; padding: 12px 20px; background: #258bcb; color: #fff; border: 0; font: inherit; cursor: pointer; }
button:disabled { opacity: .5; cursor: default; }
#go-lab-stop { font-size: .85rem; }
#go-lab-status { margin: 0; }
#go-preview-error { margin: 0 18px 14px; color: #ffb6b6; }
.privacy-note { font-size: .76rem; color: #97b1cc; }
:focus-visible { outline: 3px solid #f5c86b; outline-offset: 3px; }
@media (max-width: 560px) { .chat-scroll { padding: 15px 10px; } .chat-bubble { max-width: 82%; } #chat-form { padding: 12px; } }