:root {
  --bg: #0f1117;
  --bg-2: #161922;
  --bg-3: #1d2230;
  --border: #2a3040;
  --text: #e7e9ee;
  --muted: #9aa3b2;
  --accent: #6d8cff;
  --accent-2: #4f6ad8;
  --user: #243049;
  --danger: #e5645f;
  --radius: 12px;
}
@media (prefers-color-scheme: light) {
  :root {
    --bg: #f6f7f9; --bg-2: #fff; --bg-3: #eef1f6; --border: #dde1ea;
    --text: #1a1d24; --muted: #5a6373; --user: #e4ecff;
  }
}

* { box-sizing: border-box; }
html, body { height: 100%; margin: 0; }
body {
  font: 15px/1.5 -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  background: var(--bg); color: var(--text);
  -webkit-font-smoothing: antialiased;
}
.hidden { display: none !important; }
.muted { color: var(--muted); }
.spacer { flex: 1; }

button {
  font: inherit; cursor: pointer; border: 1px solid var(--border);
  background: var(--bg-3); color: var(--text);
  padding: 9px 14px; border-radius: 10px; transition: background .15s, border-color .15s;
}
button:hover { border-color: var(--accent); }
button.primary { background: var(--accent); border-color: var(--accent); color: #fff; }
button.primary:hover { background: var(--accent-2); }
button.block { width: 100%; }
button.link { background: none; border: none; color: var(--muted); padding: 4px; text-decoration: underline; }
button.icon { background: none; border: none; font-size: 20px; padding: 4px 8px; }
button:disabled { opacity: .55; cursor: default; }
input, textarea, select {
  font: inherit; color: var(--text); background: var(--bg); border: 1px solid var(--border);
  border-radius: 10px; padding: 10px 12px; width: 100%;
}
select { width: auto; background: var(--bg-3); }

/* ---- Auth ---- */
.auth { min-height: 100%; display: grid; place-items: center; padding: 24px; }
.card {
  background: var(--bg-2); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 28px; width: 100%; max-width: 380px; box-shadow: 0 12px 40px rgba(0,0,0,.25);
}
.card h1 { margin: 0 0 4px; font-size: 24px; }
.card .primary { width: 100%; margin: 18px 0 8px; padding: 12px; font-size: 16px; }
.card details { margin-top: 14px; border-top: 1px solid var(--border); padding-top: 12px; }
.card summary { cursor: pointer; color: var(--muted); }
.card label { display: block; margin: 12px 0 0; font-size: 13px; color: var(--muted); }
.card label input { margin-top: 5px; }
.card details button { width: 100%; margin-top: 14px; }
.hint { font-size: 12px; color: var(--muted); margin: 10px 0 0; }
.msg { min-height: 18px; margin: 12px 0 0; font-size: 13px; }
.msg.err { color: var(--danger); }
.msg.ok { color: var(--accent); }

/* ---- App layout ---- */
.app { display: grid; grid-template-columns: 270px 1fr; height: 100vh; height: 100dvh; }
.sidebar {
  background: var(--bg-2); border-right: 1px solid var(--border);
  display: flex; flex-direction: column; min-height: 0;
}
.sidebar-head { padding: 12px; }
.conv-list { flex: 1; overflow-y: auto; padding: 0 8px; }
.conv-item {
  display: flex; align-items: center; gap: 6px; padding: 9px 10px; margin-bottom: 3px;
  border-radius: 9px; cursor: pointer; color: var(--text); font-size: 14px;
}
.conv-item:hover { background: var(--bg-3); }
.conv-item.active { background: var(--bg-3); border: 1px solid var(--border); }
.conv-item .title { flex: 1; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.conv-item .del { opacity: 0; background: none; border: none; padding: 2px 6px; color: var(--muted); }
.conv-item:hover .del { opacity: 1; }
.sidebar-foot {
  border-top: 1px solid var(--border); padding: 12px;
  display: flex; align-items: center; justify-content: space-between; gap: 8px;
}

.main { display: flex; flex-direction: column; min-width: 0; height: 100vh; height: 100dvh; }
.topbar {
  display: flex; align-items: center; gap: 10px; padding: 10px 16px;
  border-bottom: 1px solid var(--border); background: var(--bg-2);
}
.topbar #menuBtn { display: none; }

.messages { flex: 1; overflow-y: auto; padding: 24px 16px; }
.msg-row { max-width: 820px; margin: 0 auto 18px; display: flex; gap: 12px; }
.msg-row .avatar {
  flex: none; width: 30px; height: 30px; border-radius: 8px; display: grid; place-items: center;
  background: var(--bg-3); font-size: 16px;
}
.msg-row.user .avatar { background: var(--user); }
.bubble { padding: 2px 0; min-width: 0; }
.bubble .who { font-size: 12px; color: var(--muted); margin-bottom: 2px; }
.bubble .content { white-space: pre-wrap; word-wrap: break-word; overflow-wrap: anywhere; }
.bubble .content code {
  background: var(--bg-3); padding: 1px 5px; border-radius: 5px; font-size: .92em;
}
.bubble .content pre {
  background: var(--bg-3); border: 1px solid var(--border); border-radius: 9px;
  padding: 12px; overflow-x: auto;
}
.bubble .content pre code { background: none; padding: 0; }
.cursor::after { content: "▍"; color: var(--accent); animation: blink 1s steps(2) infinite; }
@keyframes blink { 50% { opacity: 0; } }
.empty { max-width: 820px; margin: 12vh auto; text-align: center; color: var(--muted); }

.toggle { display: inline-flex; align-items: center; gap: 5px; font-size: 13px; color: var(--muted); cursor: pointer; user-select: none; }
.toggle input { width: auto; margin: 0; }

.thinking { margin: 0 0 8px; border: 1px solid var(--border); border-radius: 9px; background: var(--bg-3); }
.thinking summary { cursor: pointer; padding: 6px 10px; font-size: 13px; color: var(--muted); list-style: none; }
.thinking summary::-webkit-details-marker { display: none; }
.thinking[open] summary { border-bottom: 1px solid var(--border); }
.think-body {
  padding: 8px 10px; font-size: 13px; color: var(--muted);
  white-space: pre-wrap; word-wrap: break-word; overflow-wrap: anywhere;
  max-height: 280px; overflow-y: auto;
}

.composer {
  display: flex; gap: 8px; align-items: flex-end; padding: 12px 16px;
  border-top: 1px solid var(--border); background: var(--bg-2);
}
.composer textarea { flex: 1; resize: none; max-height: 200px; }
.composer button { flex: none; padding: 11px 18px; }

.backdrop { position: fixed; inset: 0; background: rgba(0,0,0,.45); z-index: 5; }

@media (max-width: 760px) {
  .app { grid-template-columns: 1fr; }
  .sidebar {
    position: fixed; z-index: 10; left: 0; top: 0; bottom: 0; width: 270px;
    transform: translateX(-100%); transition: transform .2s;
  }
  .sidebar.open { transform: translateX(0); }
  .topbar #menuBtn { display: inline-block; }
}