:root {
  color-scheme: light dark;
  --bg: #f6f6f8;
  --panel: #ffffff;
  --panel-hover: #fafafc;
  --border: #e3e3e8;
  --text: #17171a;
  --muted: #6c6c74;
  --accent: #4338ca;
  --accent-hover: #3730a3;
  --accent-fg: #ffffff;
  --accent-soft: #eeecfd;
  --ok: #16a34a;
  --bad: #dc2626;
  --bad-soft: #fdecec;
  --shadow: 0 1px 2px rgba(20, 20, 30, 0.04), 0 1px 1px rgba(20, 20, 30, 0.03);
  --shadow-md: 0 4px 12px rgba(20, 20, 30, 0.06), 0 1px 2px rgba(20, 20, 30, 0.04);
  --radius: 10px;
  --radius-sm: 7px;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #121214;
    --panel: #1b1b1e;
    --panel-hover: #202023;
    --border: #2c2c30;
    --text: #f0f0f1;
    --muted: #96969d;
    --accent: #6d64f2;
    --accent-hover: #8078f5;
    --accent-fg: #ffffff;
    --accent-soft: #211f3b;
    --bad-soft: #3a1a1a;
    --shadow: 0 1px 2px rgba(0, 0, 0, 0.3), 0 1px 1px rgba(0, 0, 0, 0.24);
    --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.35), 0 1px 2px rgba(0, 0, 0, 0.3);
  }
}

* { box-sizing: border-box; }

[hidden] { display: none !important; }

body {
  margin: 0;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  -webkit-font-smoothing: antialiased;
  background: var(--bg);
  color: var(--text);
  font-size: 15px;
  line-height: 1.5;
}

header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 0.9rem 1.75rem;
  border-bottom: 1px solid var(--border);
  background: var(--panel);
}

.brand {
  display: flex;
  align-items: center;
  gap: 0.6rem;
}

.brand-mark {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 28px;
  height: 28px;
  border-radius: 8px;
  background: var(--accent);
  color: var(--accent-fg);
  font-weight: 700;
  font-size: 0.9rem;
  letter-spacing: -0.02em;
}

.brand-name {
  font-size: 1.05rem;
  font-weight: 650;
  letter-spacing: -0.01em;
}

.status-dot {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--muted);
  display: inline-block;
  margin-left: 0.15rem;
}

.status-dot.ok { background: var(--ok); }
.status-dot.bad { background: var(--bad); }

.auth-box {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.user-info {
  font-size: 0.85rem;
  color: var(--muted);
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.5rem 1rem;
  border: 1px solid transparent;
  border-radius: var(--radius-sm);
  cursor: pointer;
  font-size: 0.88rem;
  font-weight: 550;
  font-family: inherit;
  transition: background-color 0.15s ease, border-color 0.15s ease, opacity 0.15s ease;
}

.btn-primary {
  background: var(--accent);
  color: var(--accent-fg);
}

.btn-primary:hover:not(:disabled) { background: var(--accent-hover); }

.btn-ghost {
  background: transparent;
  border-color: var(--border);
  color: var(--text);
}

.btn-ghost:hover:not(:disabled) { background: var(--panel-hover); }

.btn:disabled {
  opacity: 0.55;
  cursor: default;
}

.auth-error {
  max-width: 760px;
  margin: 1rem auto 0;
  padding: 0.7rem 1rem;
  border-radius: var(--radius-sm);
  background: var(--bad-soft);
  color: var(--bad);
  font-size: 0.88rem;
}

.signed-out-notice {
  max-width: 520px;
  margin: 4.5rem auto;
  padding: 0 1.5rem;
  text-align: center;
}

.signed-out-notice h2 {
  font-size: 1.4rem;
  font-weight: 650;
  letter-spacing: -0.01em;
  margin: 0 0 0.6rem;
}

.signed-out-notice p {
  color: var(--muted);
  font-size: 0.95rem;
  line-height: 1.55;
  margin: 0;
}

.tabs {
  display: flex;
  gap: 1.5rem;
  padding: 0 1.75rem;
  border-bottom: 1px solid var(--border);
  background: var(--panel);
  max-width: 760px;
  margin: 0 auto;
}

.tab-btn {
  border: none;
  background: transparent;
  color: var(--muted);
  padding: 0.85rem 0.1rem;
  margin-bottom: -1px;
  border-bottom: 2px solid transparent;
  cursor: pointer;
  font-size: 0.9rem;
  font-weight: 550;
  font-family: inherit;
  transition: color 0.15s ease, border-color 0.15s ease;
}

.tab-btn:hover { color: var(--text); }

.tab-btn.active {
  color: var(--accent);
  border-bottom-color: var(--accent);
}

main {
  padding: 2rem 1.75rem;
  max-width: 760px;
  margin: 0 auto;
  width: 100%;
}

.tab-panel { display: none; }
.tab-panel.active { display: block; }

form {
  display: flex;
  gap: 0.6rem;
}

form input[type="text"] {
  flex: 1;
  padding: 0.65rem 0.85rem;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  background: var(--panel);
  color: var(--text);
  font-size: 0.95rem;
  font-family: inherit;
  transition: border-color 0.15s ease;
}

form input[type="text"]:focus {
  outline: none;
  border-color: var(--accent);
}

.file-input {
  flex: 1;
  display: flex;
  align-items: center;
  padding: 0.65rem 0.85rem;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  background: var(--panel);
  color: var(--muted);
  font-size: 0.9rem;
  cursor: pointer;
  overflow: hidden;
  white-space: nowrap;
  text-overflow: ellipsis;
}

.file-input:hover { background: var(--panel-hover); }
.file-input input[type="file"] { display: none; }

.upload-hint {
  margin-top: 0.7rem;
  font-size: 0.8rem;
  color: var(--muted);
  line-height: 1.5;
}

.meta {
  margin-top: 0.7rem;
  font-size: 0.82rem;
  color: var(--muted);
  min-height: 1.1em;
}

.answer {
  margin-top: 1.1rem;
  padding: 1.1rem 1.25rem;
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  white-space: pre-wrap;
  line-height: 1.55;
}

.sources-label {
  margin-top: 1.5rem;
  font-size: 0.75rem;
  font-weight: 650;
  color: var(--muted);
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

.results {
  list-style: none;
  margin: 0.85rem 0 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 0.7rem;
}

.result-item {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 0.9rem 1.05rem;
}

.result-item .result-head {
  display: flex;
  justify-content: space-between;
  gap: 0.75rem;
  font-size: 0.75rem;
  color: var(--muted);
  margin-bottom: 0.45rem;
}

.result-item .result-head span:first-child {
  min-width: 0;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.result-item .result-text {
  font-size: 0.9rem;
  line-height: 1.5;
  white-space: pre-wrap;
}

.docs-label {
  margin-top: 2rem;
}

.doc-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 0.7rem 0.9rem;
}

.doc-item .doc-info {
  min-width: 0;
}

.doc-item .doc-source {
  font-size: 0.88rem;
  word-break: break-all;
}

.doc-item .doc-chunks {
  font-size: 0.75rem;
  color: var(--muted);
  margin-top: 0.1rem;
}

.doc-item .doc-delete {
  flex-shrink: 0;
  border: 1px solid var(--border);
  background: transparent;
  color: var(--bad);
  padding: 0.4rem 0.75rem;
  border-radius: var(--radius-sm);
  cursor: pointer;
  font-size: 0.8rem;
  font-family: inherit;
  transition: background-color 0.15s ease;
}

.doc-item .doc-delete:hover:not(:disabled) { background: var(--bad-soft); }

.doc-item .doc-delete:disabled {
  opacity: 0.6;
  cursor: default;
}

.empty, .error {
  font-size: 0.9rem;
  color: var(--muted);
  margin-top: 0.75rem;
}

.error { color: var(--bad); }

footer {
  margin-top: auto;
  padding: 1.5rem;
  text-align: center;
  font-size: 0.78rem;
  color: var(--muted);
}