* { box-sizing: border-box; }
body { margin: 0; font: 16px/1.45 system-ui, -apple-system, Segoe UI, Roboto, sans-serif; background: #f2f4f7; color: #1d2433; }
.chat { max-width: 640px; height: 100dvh; margin: 0 auto; display: flex; flex-direction: column; background: #fff; }
.chat__header { padding: 14px 16px; font-weight: 600; border-bottom: 1px solid #e3e7ee; }
.chat__log { flex: 1; overflow-y: auto; list-style: none; margin: 0; padding: 16px; display: flex; flex-direction: column; gap: 8px; }
.msg { max-width: 82%; padding: 9px 12px; border-radius: 14px; white-space: pre-wrap; overflow-wrap: anywhere; }
.msg--agent, .msg--person { align-self: flex-start; background: #eef1f6; }
.msg--visitor { align-self: flex-end; background: #2f6fde; color: #fff; }
.msg__who { display: block; font-size: 12px; opacity: .7; margin-bottom: 2px; }
.chat__status { margin: 0 16px 8px; font-size: 14px; color: #5b6475; }
.chat__form { display: flex; gap: 8px; padding: 12px 16px; border-top: 1px solid #e3e7ee; }
.chat__form input { flex: 1; padding: 10px 12px; font: inherit; border: 1px solid #c9d0db; border-radius: 10px; }
.chat__form button { padding: 10px 16px; font: inherit; border: 0; border-radius: 10px; background: #2f6fde; color: #fff; cursor: pointer; }
.chat__form button:disabled { opacity: .5; cursor: default; }