:root {
  --bg: #0f1117;
  --bg-secondary: #171a23;
  --bg-tertiary: #1e2230;
  --border: #2a2f3f;
  --text: #e8eaf0;
  --text-dim: #9aa0b4;
  --accent: #f6821f;
  --accent-hover: #ff9a45;
  --danger: #e5484d;
  --success: #46a758;
  --radius: 12px;
}

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

html, body { height: 100%; }

body {
  font-family: "Segoe UI", Tahoma, system-ui, sans-serif;
  background: var(--bg);
  color: var(--text);
  overflow: hidden;
}

#app { display: flex; height: 100vh; }

/* Sidebar */
#sidebar {
  width: 260px;
  min-width: 260px;
  background: var(--bg-secondary);
  border-left: 1px solid var(--border);
  display: flex;
  flex-direction: column;
}

.sidebar-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 16px;
  border-bottom: 1px solid var(--border);
}

.sidebar-header h1 {
  font-size: 18px;
  background: linear-gradient(90deg, var(--accent), #f5a623);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

#new-chat-btn {
  width: 32px; height: 32px;
  border-radius: 8px;
  border: none;
  background: var(--accent);
  color: #fff;
  font-size: 18px;
  cursor: pointer;
  transition: background 0.2s;
}
#new-chat-btn:hover { background: var(--accent-hover); }

#session-list { flex: 1; overflow-y: auto; padding: 8px; }

.session-item {
  padding: 10px 12px;
  margin-bottom: 4px;
  border-radius: 8px;
  cursor: pointer;
  font-size: 13px;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  color: var(--text-dim);
  display: flex;
  align-items: center;
  gap: 8px;
  transition: background 0.15s;
}
.session-item:hover { background: var(--bg-tertiary); color: var(--text); }
.session-item.active { background: var(--bg-tertiary); color: var(--accent); }
.session-item .del {
  margin-right: auto;
  opacity: 0;
  background: none;
  border: none;
  color: var(--danger);
  cursor: pointer;
  font-size: 14px;
}
.session-item:hover .del { opacity: 1; }

.sidebar-footer { padding: 12px; border-top: 1px solid var(--border); }
#docs-btn {
  width: 100%;
  padding: 10px;
  border-radius: 8px;
  border: 1px solid var(--border);
  background: var(--bg-tertiary);
  color: var(--text);
  cursor: pointer;
  font-size: 14px;
}
#docs-btn:hover { border-color: var(--accent); }

/* Main */
#main { flex: 1; display: flex; flex-direction: column; min-width: 0; }

#topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 10px 20px;
  border-bottom: 1px solid var(--border);
  background: var(--bg-secondary);
  flex-wrap: wrap;
  gap: 8px;
}

.topbar-group { display: flex; align-items: center; gap: 10px; }

#model-select {
  background: var(--bg-tertiary);
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 6px 10px;
  font-size: 13px;
  cursor: pointer;
}

.toggle {
  display: flex;
  align-items: center;
  gap: 5px;
  font-size: 13px;
  color: var(--text-dim);
  cursor: pointer;
  user-select: none;
}
.toggle input { accent-color: var(--accent); }

#usage-indicator { font-size: 12px; color: var(--text-dim); }

/* Messages */
#messages {
  flex: 1;
  overflow-y: auto;
  padding: 20px;
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.msg {
  max-width: 78%;
  padding: 12px 16px;
  border-radius: var(--radius);
  line-height: 1.7;
  font-size: 14.5px;
  white-space: pre-wrap;
  word-break: break-word;
}
.msg.user {
  align-self: flex-start;
  background: var(--accent);
  color: #1a1208;
  border-bottom-right-radius: 4px;
}
.msg.assistant {
  align-self: flex-end;
  background: var(--bg-tertiary);
  border: 1px solid var(--border);
  border-bottom-left-radius: 4px;
}
.msg.error {
  align-self: flex-end;
  background: rgba(229, 72, 77, 0.15);
  border: 1px solid var(--danger);
  color: var(--danger);
}

.msg .meta { display: block; font-size: 11px; color: var(--text-dim); margin-bottom: 6px; }

.sources {
  margin-top: 8px;
  padding-top: 8px;
  border-top: 1px dashed var(--border);
  font-size: 12px;
  color: var(--text-dim);
}
.sources summary { cursor: pointer; color: var(--accent); }
.sources li { margin: 4px 0 4px 16px; }

.typing { display: inline-flex; gap: 4px; padding: 4px 0; }
.typing span {
  width: 7px; height: 7px;
  border-radius: 50%;
  background: var(--text-dim);
  animation: blink 1.2s infinite;
}
.typing span:nth-child(2) { animation-delay: 0.2s; }
.typing span:nth-child(3) { animation-delay: 0.4s; }
@keyframes blink {
  0%, 100% { opacity: 0.2; }
  50% { opacity: 1; }
}

/* Input */
#chat-form {
  display: flex;
  gap: 10px;
  padding: 14px 20px;
  border-top: 1px solid var(--border);
  background: var(--bg-secondary);
}

#input {
  flex: 1;
  resize: none;
  background: var(--bg-tertiary);
  border: 1px solid var(--border);
  border-radius: 10px;
  color: var(--text);
  padding: 12px 14px;
  font-size: 14.5px;
  font-family: inherit;
  max-height: 160px;
  outline: none;
}
#input:focus { border-color: var(--accent); }

#send-btn {
  padding: 0 24px;
  border: none;
  border-radius: 10px;
  background: var(--accent);
  color: #fff;
  font-size: 14px;
  cursor: pointer;
  transition: background 0.2s;
}
#send-btn:hover { background: var(--accent-hover); }
#send-btn:disabled { opacity: 0.5; cursor: not-allowed; }

/* Modal */
.modal {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.6);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 100;
}
.modal.hidden { display: none; }

.modal-content {
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  width: min(520px, 90vw);
  max-height: 80vh;
  overflow-y: auto;
  padding: 20px;
}

.modal-header { display: flex; justify-content: space-between; align-items: center; margin-bottom: 16px; }
.modal-header h2 { font-size: 17px; }
.modal-close { background: none; border: none; color: var(--text-dim); font-size: 18px; cursor: pointer; }
.modal-close:hover { color: var(--danger); }

#upload-form { display: flex; gap: 10px; margin-bottom: 16px; align-items: center; flex-wrap: wrap; }
#file-input { flex: 1; font-size: 13px; color: var(--text-dim); }
#upload-form button {
  padding: 8px 18px;
  background: var(--accent);
  color: #fff;
  border: none;
  border-radius: 8px;
  cursor: pointer;
}

#docs-list { list-style: none; }
#docs-list li {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 10px;
  border-radius: 8px;
  background: var(--bg-tertiary);
  margin-bottom: 6px;
  font-size: 13.5px;
}
#docs-list .doc-meta { color: var(--text-dim); font-size: 11.5px; margin-top: 2px; }
#docs-list .doc-del {
  background: none;
  border: 1px solid var(--danger);
  color: var(--danger);
  border-radius: 6px;
  padding: 4px 10px;
  cursor: pointer;
  font-size: 12px;
}
#docs-list .doc-del:hover { background: var(--danger); color: #fff; }

/* Scrollbar */
::-webkit-scrollbar { width: 8px; }
::-webkit-scrollbar-thumb { background: var(--border); border-radius: 4px; }
::-webkit-scrollbar-track { background: transparent; }

@media (max-width: 720px) {
  #sidebar { display: none; }
  .msg { max-width: 92%; }
}