*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  background: #f5f5f5;
  color: #1a1a1a;
  height: 100vh;
  display: flex;
  flex-direction: column;
}

header {
  background: #fff;
  border-bottom: 1px solid #e0e0e0;
  padding: 14px 24px;
  display: flex;
  align-items: baseline;
  gap: 12px;
}

.logo { font-size: 1.2rem; font-weight: 700; color: #1a1a1a; }
.tagline { font-size: 0.85rem; color: #888; }

main {
  display: grid;
  grid-template-columns: 230px 280px 1fr;
  gap: 0;
  flex: 1;
  overflow: hidden;
}

.panel {
  background: #fff;
  display: flex;
  flex-direction: column;
  overflow: hidden;
}

#sessions-panel {
  border-right: 1px solid #e0e0e0;
  padding: 20px 14px;
  gap: 12px;
}

.sessions-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 6px;
}

#new-chat-btn {
  background: #4a6cf7;
  color: #fff;
  border: none;
  border-radius: 6px;
  padding: 5px 10px;
  font-size: 0.78rem;
  font-weight: 600;
  cursor: pointer;
  transition: background 0.2s;
}
#new-chat-btn:hover { background: #3a5ce6; }

.session-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 4px;
  overflow-y: auto;
}

.session-item {
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 8px 8px 8px 10px;
  border-radius: 6px;
  font-size: 0.83rem;
  color: #444;
  cursor: pointer;
  transition: background 0.15s;
}
.session-item:hover { background: #f2f2f2; }
.session-item.active { background: #e8edff; color: #2b3a8c; font-weight: 600; }

.session-title {
  flex: 1;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.session-actions {
  display: none;
  gap: 2px;
  flex-shrink: 0;
}
.session-item:hover .session-actions,
.session-item.active .session-actions { display: flex; }

.session-btn {
  background: none;
  border: none;
  color: #999;
  cursor: pointer;
  font-size: 0.95rem;
  line-height: 1;
  padding: 0 3px;
  border-radius: 4px;
}
.session-btn:hover { color: #4a6cf7; background: #dfe6ff; }

.session-edit-input {
  width: 100%;
  padding: 5px 8px;
  border: 1px solid #4a6cf7;
  border-radius: 5px;
  font-size: 0.83rem;
  outline: none;
}

#upload-panel {
  border-right: 1px solid #e0e0e0;
  padding: 20px;
  gap: 16px;
}

#chat-panel {
  padding: 20px;
  gap: 16px;
}

h2 {
  font-size: 0.8rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: #888;
}

/* Drop zone */
.drop-zone {
  border: 2px dashed #d0d0d0;
  border-radius: 8px;
  padding: 24px 16px;
  text-align: center;
  cursor: pointer;
  color: #888;
  transition: border-color 0.2s, background 0.2s;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
}

.drop-zone:hover, .drop-zone.drag-over {
  border-color: #4a6cf7;
  background: #f0f3ff;
  color: #4a6cf7;
}

.drop-zone p { font-size: 0.85rem; }

.browse-link {
  color: #4a6cf7;
  cursor: pointer;
  text-decoration: underline;
}

/* Status */
.status-msg {
  font-size: 0.82rem;
  padding: 8px 12px;
  border-radius: 6px;
}
.status-msg.success { background: #e6f4ea; color: #2e7d32; }
.status-msg.error   { background: #fce8e6; color: #c62828; }
.status-msg.loading { background: #e8f0fe; color: #1a73e8; }
.hidden { display: none; }

/* Doc list */
.doc-list { list-style: none; display: flex; flex-direction: column; gap: 6px; }
.doc-list li {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 8px 10px;
  background: #f9f9f9;
  border-radius: 6px;
  font-size: 0.83rem;
  color: #333;
  border: 1px solid #ececec;
}
.doc-list li::before {
  content: "📄";
  font-size: 1rem;
  flex-shrink: 0;
}

.doc-name { flex: 1; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }

.delete-btn {
  background: none;
  border: none;
  color: #aaa;
  cursor: pointer;
  font-size: 1.1rem;
  line-height: 1;
  padding: 0 2px;
  flex-shrink: 0;
}
.delete-btn:hover { color: #e53935; }

/* Chat */
.chat-messages {
  flex: 1;
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  gap: 16px;
  padding-right: 4px;
}

.empty-state {
  margin: auto;
  color: #aaa;
  font-size: 0.9rem;
  text-align: center;
}

.message { display: flex; flex-direction: column; gap: 6px; }

.message.user .bubble {
  align-self: flex-end;
  background: #4a6cf7;
  color: #fff;
  border-radius: 16px 16px 4px 16px;
  padding: 10px 14px;
  max-width: 80%;
  font-size: 0.9rem;
}

.message.assistant .bubble {
  align-self: flex-start;
  background: #f1f1f1;
  color: #1a1a1a;
  border-radius: 16px 16px 16px 4px;
  padding: 10px 14px;
  max-width: 90%;
  font-size: 0.9rem;
  line-height: 1.5;
}

.message.assistant .bubble.warning {
  background: #fff8e1;
  color: #7c5e00;
}

.sources {
  align-self: flex-start;
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  padding-left: 4px;
}

.source-tag {
  font-size: 0.75rem;
  background: #e8eaed;
  color: #555;
  padding: 2px 8px;
  border-radius: 10px;
}

.thinking {
  align-self: flex-start;
  background: #f1f1f1;
  border-radius: 16px;
  padding: 10px 14px;
  font-size: 0.85rem;
  color: #888;
}

/* Filter bar */
.filter-bar {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 0.82rem;
  color: #666;
}

.filter-bar select {
  flex: 1;
  padding: 5px 8px;
  border: 1px solid #d0d0d0;
  border-radius: 6px;
  font-size: 0.82rem;
  background: #fff;
  outline: none;
  cursor: pointer;
}

.filter-bar select:focus { border-color: #4a6cf7; }

/* Ask form */
.ask-form {
  display: flex;
  gap: 8px;
  padding-top: 4px;
}

.ask-form input {
  flex: 1;
  padding: 10px 14px;
  border: 1px solid #d0d0d0;
  border-radius: 8px;
  font-size: 0.9rem;
  outline: none;
  transition: border-color 0.2s;
}

.ask-form input:focus { border-color: #4a6cf7; }

.ask-form button {
  padding: 10px 20px;
  background: #4a6cf7;
  color: #fff;
  border: none;
  border-radius: 8px;
  font-size: 0.9rem;
  font-weight: 600;
  cursor: pointer;
  transition: background 0.2s;
}

.ask-form button:hover { background: #3a5ce6; }
.ask-form button:disabled { background: #a0a0a0; cursor: not-allowed; }