:root {
  --bg: #f6f7fb;
  --panel: #ffffff;
  --text: #1c2030;
  --muted: #646b80;
  --line: #e3e6ef;
  --accent: #4f46e5;
  --accent-soft: #eef0ff;
  --user: #4f46e5;
  --bot: #f1f3f9;
  --warn-bg: #fff6e0;
  --warn-text: #7a5300;
  --error: #c62828;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #12141c;
    --panel: #1b1e29;
    --text: #e8eaf2;
    --muted: #9aa1b5;
    --line: #2c3040;
    --accent: #8b85ff;
    --accent-soft: #262a45;
    --user: #5b54e8;
    --bot: #242838;
    --warn-bg: #3a3017;
    --warn-text: #f3d48a;
    --error: #ff7b7b;
  }
}

* { box-sizing: border-box; }
[hidden] { display: none !important; }
body {
  margin: 0;
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.5;
}
a { color: var(--accent); }

.nav { border-bottom: 1px solid var(--line); background: var(--panel); position: sticky; top: 0; z-index: 10; }
.nav-inner {
  max-width: 1200px; margin: 0 auto; padding: 10px 16px;
  display: flex; align-items: center; justify-content: space-between; gap: 12px;
}
.nav-brand { display: flex; align-items: center; gap: 8px; font-weight: 700; color: var(--text); text-decoration: none; }
.brand-mark { font-size: 20px; }
.nav-links { display: flex; gap: 4px; }
.nav-links a {
  padding: 6px 12px; border-radius: 8px; font-size: 14px; color: var(--muted); text-decoration: none;
}
.nav-links a:hover { color: var(--text); }
.nav-links a.active { background: var(--accent-soft); color: var(--accent); font-weight: 600; }
@media (max-width: 480px) { .nav-brand span:last-child { display: none; } }

.top {
  max-width: 1200px; margin: 0 auto; padding: 20px 16px 8px;
  display: flex; align-items: center; justify-content: space-between; gap: 12px;
}
.brand { display: flex; align-items: center; gap: 12px; }
.logo { font-size: 34px; }
.top h1 { margin: 0; font-size: 22px; }
.top p { margin: 0; color: var(--muted); font-size: 14px; }
.gh {
  border: 1px solid var(--line); padding: 7px 14px; border-radius: 8px;
  text-decoration: none; font-size: 14px; white-space: nowrap; background: var(--panel);
}

.layout {
  max-width: 1200px; margin: 0 auto; padding: 12px 16px;
  display: grid; grid-template-columns: 340px 1fr; gap: 16px;
}
.panel {
  background: var(--panel); border: 1px solid var(--line); border-radius: 14px; padding: 18px;
}
.panel h2 { margin: 0 0 12px; font-size: 16px; }

.drop {
  display: flex; flex-direction: column; align-items: center; gap: 4px; text-align: center;
  border: 2px dashed var(--line); border-radius: 12px; padding: 26px 12px; cursor: pointer;
  transition: border-color .15s, background .15s;
}
.drop:hover, .drop.over { border-color: var(--accent); background: var(--accent-soft); }
.drop-icon { font-size: 26px; }
.drop small { color: var(--muted); }

.link-btn {
  background: none; border: 0; color: var(--accent); cursor: pointer;
  padding: 8px 0; font: inherit; font-size: 14px; text-decoration: underline;
}

.progress { margin-top: 12px; }
.bar { height: 8px; background: var(--line); border-radius: 99px; overflow: hidden; }
#bar-fill { height: 100%; width: 0; background: var(--accent); transition: width .3s; }
.progress p { margin: 6px 0 0; font-size: 14px; color: var(--muted); }

.doc-info { margin-top: 12px; padding: 12px; border-radius: 10px; background: var(--accent-soft); }
.doc-name { margin: 0; font-weight: 600; word-break: break-word; }
.doc-meta { margin: 2px 0 0; font-size: 14px; color: var(--muted); }
.notice {
  margin: 8px 0 0; padding: 8px 10px; border-radius: 8px; font-size: 13px;
  background: var(--warn-bg); color: var(--warn-text);
}

.how { margin-top: 16px; font-size: 14px; color: var(--muted); }
.how summary { cursor: pointer; color: var(--text); font-weight: 600; }
.how ol { padding-left: 20px; }

.dev { margin-top: 18px; padding-top: 16px; border-top: 1px solid var(--line); }
.dev-head { display: flex; align-items: center; gap: 12px; }
.avatar {
  width: 44px; height: 44px; border-radius: 50%; flex-shrink: 0;
  display: grid; place-items: center; font-weight: 700;
  background: var(--accent); color: #fff;
}
.dev-name { margin: 0; font-weight: 700; }
.dev-role { margin: 0; font-size: 13px; color: var(--muted); }
.dev-pitch { margin: 10px 0 12px; font-size: 14px; color: var(--muted); }
.dev-buttons { display: flex; flex-wrap: wrap; gap: 8px; }
.dev-contact { list-style: none; padding: 0; margin: 12px 0 0; font-size: 14px; }
.dev-contact li { margin: 3px 0; overflow-wrap: anywhere; }
.btn {
  display: inline-block; padding: 8px 14px; border-radius: 8px; font-size: 14px; font-weight: 600;
  text-decoration: none; border: 1px solid var(--line); color: var(--text); background: var(--panel);
}
.btn.primary { background: var(--accent); border-color: var(--accent); color: #fff; }

.chat-panel { display: flex; flex-direction: column; min-height: 70vh; }
.messages { flex: 1; overflow-y: auto; display: flex; flex-direction: column; gap: 12px; padding: 4px 2px 12px; max-height: 62vh; }
.empty { margin: auto; color: var(--muted); }
.msg { max-width: 85%; padding: 10px 14px; border-radius: 14px; word-wrap: break-word; }
.msg.user { align-self: flex-end; background: var(--user); color: #fff; border-bottom-right-radius: 4px; }
.msg.bot { align-self: flex-start; background: var(--bot); border-bottom-left-radius: 4px; }
.msg.error { color: var(--error); }
.msg p { margin: 0 0 6px; }
.msg p:last-child { margin-bottom: 0; }
.msg ul { margin: 4px 0 6px; padding-left: 20px; }
.typing { color: var(--muted); font-style: italic; }

.cite {
  display: inline-block; border: 0; cursor: pointer; font: inherit; font-size: 12px; font-weight: 600;
  padding: 0 7px; margin: 0 1px; border-radius: 99px; background: var(--accent-soft); color: var(--accent);
}
.sources { margin-top: 8px; font-size: 13px; }
.sources summary { cursor: pointer; color: var(--muted); }
.source {
  margin: 6px 0 0; padding: 8px 10px; border-left: 3px solid var(--accent);
  background: var(--panel); border-radius: 6px;
}
.source.flash { outline: 2px solid var(--accent); }
.source b { display: block; color: var(--accent); margin-bottom: 2px; }

.suggestions { display: flex; flex-wrap: wrap; gap: 8px; margin-bottom: 10px; }
.suggestions button {
  border: 1px solid var(--line); background: var(--panel); color: var(--text);
  border-radius: 99px; padding: 6px 12px; cursor: pointer; font: inherit; font-size: 13px;
}
.suggestions button:hover { border-color: var(--accent); color: var(--accent); }

.ask { display: flex; gap: 8px; }
.ask input {
  flex: 1; min-width: 0; padding: 11px 14px; border-radius: 10px; font: inherit;
  border: 1px solid var(--line); background: var(--bg); color: var(--text);
}
.ask input:focus { outline: 2px solid var(--accent); border-color: transparent; }
.ask button, .ask button:disabled {
  padding: 0 20px; border: 0; border-radius: 10px; font: inherit; font-weight: 600;
  background: var(--accent); color: #fff; cursor: pointer;
}
.ask button:disabled { opacity: .5; cursor: not-allowed; }

.foot { text-align: center; color: var(--muted); font-size: 13px; padding: 16px; }

@media (max-width: 820px) {
  .layout { grid-template-columns: 1fr; }
  .chat-panel { min-height: 60vh; }
  .msg { max-width: 95%; }
  .top p { display: none; }
}