:root {
  --ink: #16181d;
  --muted: #6b7280;
  --line: #e5e7eb;
  --bg: #f7f7f5;
  --card: #ffffff;
  --blue: #165edd;
  --blue-soft: #eef3fe;
  --radius: 10px;
  --font: -apple-system, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
}

* { box-sizing: border-box; }
html, body { height: 100%; }
body { margin: 0; font-family: var(--font); color: var(--ink); background: var(--bg); }
button { font-family: inherit; cursor: pointer; }
[hidden] { display: none !important; }

/* ── login ── */
.login { display: flex; align-items: center; justify-content: center; padding: 1.5rem; }
.login-card {
  background: var(--card); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 2rem 1.75rem; max-width: 25rem; width: 100%;
}
.brand { font-weight: 700; letter-spacing: .5px; color: var(--blue); }
.login-card h1 { font-size: 1.15rem; margin: 1rem 0 .35rem; }
.login-card .sub { color: var(--muted); font-size: .9rem; margin: 0 0 1.25rem; }
.login-card form { display: flex; flex-direction: column; gap: .6rem; }
.login-card input, .composer textarea {
  border: 1px solid var(--line); border-radius: 8px; padding: .7rem .8rem; font-size: .95rem; width: 100%;
}
.login-card button {
  background: var(--blue); color: #fff; border: 0; border-radius: 8px; padding: .7rem; font-size: .95rem; font-weight: 500;
}
.login-card button:disabled { opacity: .5; }
.msg { color: var(--muted); font-size: .9rem; margin-top: 1rem; }

/* ── app shell ── */
.app { display: flex; flex-direction: column; height: 100%; }
.topbar {
  display: flex; align-items: center; gap: .75rem;
  padding: .6rem 1rem; background: var(--card); border-bottom: 1px solid var(--line);
}
.topbar .client { font-weight: 600; }
.topbar .spacer { flex: 1; }
.topbar .site-link { color: var(--blue); text-decoration: none; font-size: .875rem; }
.topbar .ghost { background: transparent; border: 1px solid var(--line); border-radius: 7px; padding: .35rem .7rem; font-size: .825rem; color: var(--muted); }

.panes { flex: 1; display: grid; grid-template-columns: minmax(320px, 2fr) 3fr; min-height: 0; }

/* left: conversation */
.convo { display: flex; flex-direction: column; min-height: 0; border-right: 1px solid var(--line); background: var(--bg); }
.messages { flex: 1; overflow-y: auto; padding: 1rem; display: flex; flex-direction: column; gap: .75rem; }
.m { max-width: 90%; padding: .6rem .8rem; border-radius: 10px; font-size: .925rem; line-height: 1.45; white-space: pre-wrap; }
.m.user { align-self: flex-end; background: var(--blue); color: #fff; border-bottom-right-radius: 3px; }
.m.assistant { align-self: flex-start; background: var(--card); border: 1px solid var(--line); border-bottom-left-radius: 3px; }
.m.status { align-self: flex-start; color: var(--muted); font-size: .8rem; font-style: italic; padding: 0 .3rem; }
.m.error { align-self: flex-start; background: #fdecec; color: #a12; border: 1px solid #f5c6c6; }

.composer { display: flex; gap: .5rem; padding: .75rem; border-top: 1px solid var(--line); background: var(--card); }
.composer textarea { resize: none; max-height: 8rem; }
.composer button { background: var(--blue); color: #fff; border: 0; border-radius: 8px; padding: 0 1.1rem; font-weight: 500; }
.composer button:disabled { opacity: .5; }

/* right: panel */
.panel { display: flex; flex-direction: column; min-height: 0; background: var(--card); }
.panel-tabs { display: flex; gap: .25rem; padding: .5rem .75rem 0; border-bottom: 1px solid var(--line); }
.panel-tabs button {
  background: transparent; border: 0; padding: .5rem .8rem; font-size: .85rem; color: var(--muted);
  border-bottom: 2px solid transparent;
}
.panel-tabs button.active { color: var(--ink); border-bottom-color: var(--blue); font-weight: 500; }
.panel-body { flex: 1; overflow-y: auto; padding: 1.25rem; }

.card {
  border: 1px solid var(--line); border-radius: var(--radius); padding: 1rem; margin-bottom: .9rem; background: var(--card);
}
.card h3 { margin: 0 0 .5rem; font-size: .95rem; }
.card p { margin: .25rem 0; font-size: .875rem; color: var(--muted); }
.card .big { font-size: 1.6rem; font-weight: 600; color: var(--ink); }
.card a.button, .panel-body a.button {
  display: inline-block; margin-top: .6rem; background: var(--blue); color: #fff; text-decoration: none;
  padding: .55rem .9rem; border-radius: 8px; font-size: .875rem;
}
.inbox-item { border-bottom: 1px solid var(--line); padding: .7rem 0; font-size: .875rem; }
.inbox-item:last-child { border-bottom: 0; }
.inbox-item .from { font-weight: 600; }
.inbox-item .when { color: var(--muted); font-size: .75rem; }
.empty { color: var(--muted); font-size: .875rem; }

@media (max-width: 860px) {
  .panes { grid-template-columns: 1fr; grid-template-rows: 1fr auto; }
  .panel { max-height: 45vh; border-top: 1px solid var(--line); }
}