body {
  font-family: system-ui, -apple-system, Segoe UI, Roboto, sans-serif;
  margin: 0;
  background: #f7f7f8;
  color: #111;
}

.wrap {
  max-width: 980px;
  margin: 0 auto;
  padding: 24px;
}

.card {
  background: #fff;
  border-radius: 14px;
  box-shadow: 0 1px 6px rgba(0, 0, 0, .08);
  padding: 18px;
}

h1 {
  font-size: 26px;
  margin: 0 0 10px;
  line-height: 1.2;
}

.muted {
  color: #666;
  font-size: 13px;
}

label {
  font-weight: 600;
  display: block;
  margin: 12px 0 6px;
}

textarea {
  width: 100%;
  min-height: 110px;
  resize: vertical;
  padding: 10px 12px;
  border: 1px solid #ddd;
  border-radius: 10px;
  font-size: 15px;
  box-sizing: border-box;
}

.row {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
  align-items: center;
  margin-top: 12px;
}

button {
  border: 0;
  background: #111;
  color: #fff;
  padding: 10px 14px;
  border-radius: 10px;
  font-weight: 650;
  cursor: pointer;
  min-height: 38px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  line-height: 1.2;
}

button:disabled {
  opacity: .6;
  cursor: not-allowed;
}

select {
  font-size: 14px;
}

.section {
  margin-top: 16px;
}

.section h2 {
  font-size: 16px;
  margin: 0 0 8px;
}

.pill {
  display: inline-block;
  padding: 2px 8px;
  border-radius: 999px;
  background: #eee;
  font-size: 12px;
  margin-left: 8px;
}

details {
  margin-top: 10px;
}

details>summary {
  cursor: pointer;
  font-weight: 650;
}

.err {
  color: #b00020;
  white-space: pre-wrap;
  margin-top: 10px;
}

.sources {
  margin-top: 10px;
  font-size: 13px;
  color: #333;
}

.sources ul {
  margin: 8px 0 0;
  padding-left: 18px;
}

code {
  background: #f1f1f1;
  padding: 1px 5px;
  border-radius: 6px;
}

/* Navigation topbar */
.nav-topbar {
  display: flex;
  align-items: center;
  gap: 0;
  background: #111;
  border-radius: 12px;
  overflow: hidden;
  margin-bottom: 16px;
}

.nav-topbar a {
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 11px 20px;
  color: #aaa;
  text-decoration: none;
  font-size: 14px;
  font-weight: 600;
  transition: background .15s, color .15s;
  position: relative;
}

.nav-topbar a:hover {
  background: #222;
  color: #fff;
}

.nav-topbar a.active {
  background: #272727;
  color: #fff;
}

.nav-topbar a.active::after {
  content: "";
  position: absolute;
  bottom: 0;
  left: 16px;
  right: 16px;
  height: 2px;
  background: #4a9eff;
  border-radius: 2px;
}

.nav-topbar .nav-icon {
  font-size: 15px;
  line-height: 1;
}

.nav-topbar .spacer {
  flex: 1;
}

.nav-topbar .back-link {
  color: #6ba3e8;
  font-weight: 500;
  font-size: 13px;
  padding: 11px 18px;
}

.nav-topbar .back-link:hover {
  color: #9dc4f5;
  background: #1a1a1a;
}

.topbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 10px;
  margin-bottom: 10px;
}

/* Markdown answer styling */
.answer {
  border: 1px solid #eee;
  border-radius: 12px;
  padding: 12px 14px;
  background: #fcfcfc;
  min-height: 24px;
}

.answer p {
  margin: 0 0 10px;
  line-height: 1.6;
}

.answer p:last-child {
  margin-bottom: 0;
}

.answer ul,
.answer ol {
  margin: 4px 0 10px;
  padding-left: 22px;
}

.answer li {
  margin-bottom: 4px;
  line-height: 1.5;
}

.answer h3,
.answer h4 {
  margin: 14px 0 6px;
  font-size: 15px;
}

.answer pre {
  background: #f1f1f1;
  padding: 10px;
  border-radius: 8px;
  overflow-x: auto;
}

.answer code {
  font-size: 13px;
}

.answer blockquote {
  border-left: 3px solid #ddd;
  margin: 8px 0;
  padding: 4px 12px;
  color: #555;
}

.answer strong {
  font-weight: 650;
}

/* Thinking indicator */
.thinking {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  color: #888;
  font-size: 14px;
}

.thinking-dots span {
  display: inline-block;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: #aaa;
  animation: dot-pulse 1.4s ease-in-out infinite;
}

.thinking-dots span:nth-child(2) {
  animation-delay: 0.2s;
}

.thinking-dots span:nth-child(3) {
  animation-delay: 0.4s;
}

@keyframes dot-pulse {
  0%, 80%, 100% {
    opacity: 0.3;
    transform: scale(0.8);
  }
  40% {
    opacity: 1;
    transform: scale(1);
  }
}

/* Cursor blink while streaming */
.streaming-cursor::after {
  content: "▊";
  animation: blink 0.7s step-end infinite;
  color: #999;
  margin-left: 1px;
}

@keyframes blink {
  50% {
    opacity: 0;
  }
}

/* Mode toggle */
.mode-toggle {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 13px;
  font-weight: 400;
  color: #666;
  cursor: pointer;
}

.mode-toggle input[type="checkbox"] {
  margin: 0;
}

/* Chat conversation view */
.chat-container {
  margin-top: 16px;
  display: none;
}

.chat-container.visible {
  display: block;
}

.chat-scroll {
  max-height: 600px;
  overflow-y: auto;
  border: 1px solid #eee;
  border-radius: 12px;
  background: #fafafa;
  padding: 8px;
}

.chat-scroll::-webkit-scrollbar {
  width: 6px;
}

.chat-scroll::-webkit-scrollbar-track {
  background: transparent;
}

.chat-scroll::-webkit-scrollbar-thumb {
  background: #ccc;
  border-radius: 3px;
}

.chat-bubble {
  margin-bottom: 12px;
  display: flex;
  flex-direction: column;
}

.single-question-bubble {
  margin-bottom: 16px;
}

.chat-bubble.user {
  align-items: flex-end;
}

.chat-bubble.assistant {
  align-items: flex-start;
}

.chat-bubble-label {
  font-size: 11px;
  font-weight: 600;
  color: #888;
  margin-bottom: 3px;
  padding: 0 6px;
}

.chat-bubble-content {
  max-width: 85%;
  padding: 10px 14px;
  border-radius: 12px;
  font-size: 14px;
  line-height: 1.6;
}

.chat-bubble.user .chat-bubble-content {
  background: #111;
  color: #fff;
  border-bottom-right-radius: 4px;
}

.chat-bubble.assistant .chat-bubble-content {
  background: #fff;
  border: 1px solid #eee;
  border-bottom-left-radius: 4px;
  color: #222;
}

.chat-bubble-content p {
  margin: 0 0 8px;
}

.chat-bubble-content p:last-child {
  margin-bottom: 0;
}

.chat-bubble-content ul,
.chat-bubble-content ol {
  margin: 4px 0 8px;
  padding-left: 20px;
}

.chat-bubble-content li {
  margin-bottom: 3px;
}

.chat-bubble-meta {
  display: flex;
  gap: 6px;
  margin-top: 4px;
  padding: 0 6px;
}

.chat-bubble-meta .pill {
  margin-left: 0;
  font-size: 11px;
}

.chat-sources {
  font-size: 12px;
  color: #888;
  padding: 0 6px;
  margin-top: 2px;
}

.chat-clear {
  background: none;
  border: 1px solid #ddd;
  color: #666;
  padding: 4px 10px;
  border-radius: 8px;
  font-size: 12px;
  font-weight: 600;
  cursor: pointer;
}

.chat-clear:hover {
  background: #f1f1f1;
  color: #333;
}

.chat-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 8px;
}

.chat-header h2 {
  font-size: 16px;
  margin: 0;
}

.chat-turn-count {
  font-size: 12px;
  color: #999;
}

/* Hide single-question sections in chat mode */
.single-mode-only {
  /* controlled by JS */
}

/* Problem section */
.problem-row {
  margin-top: 8px;
}

.problem-btn {
  background: #2d5a27;
  font-size: 13px;
  padding: 0 14px;
  display: none;
}

.problem-btn:hover {
  background: #3d7a35;
}

.problem-section {
  margin-top: 14px;
  display: none;
}

.problem-section.visible {
  display: block;
}

.box-title {
  font-size: 16px;
  font-weight: 650;
  margin: 0 0 8px;
  line-height: 1.3;
}

details > summary.box-title {
  cursor: pointer;
  margin-bottom: 0;
}

.problem-box {
  border: 1px solid #d4edda;
  border-radius: 12px;
  padding: 14px;
  background: #f0f7f0;
}

.problem-box p {
  margin: 0 0 10px;
  line-height: 1.6;
}

.problem-box p:last-child {
  margin-bottom: 0;
}

.problem-box ul,
.problem-box ol {
  margin: 4px 0 10px;
  padding-left: 22px;
}

.problem-box li {
  margin-bottom: 4px;
  line-height: 1.5;
}

.problem-box strong {
  font-weight: 650;
}

.answer-input-area {
  margin-top: 12px;
  display: none;
}

.answer-input-area.visible {
  display: block;
}

.answer-input-area label {
  font-size: 14px;
  margin: 0 0 6px;
}

.answer-input {
  width: 100%;
  min-height: 70px;
  resize: vertical;
  padding: 10px 12px;
  border: 1px solid #ddd;
  border-radius: 10px;
  font-size: 14px;
  box-sizing: border-box;
  font-family: system-ui, -apple-system, Segoe UI, Roboto, sans-serif;
}

.submit-answer-btn {
  background: #0b57d0;
  font-size: 13px;
  padding: 0 14px;
  margin-top: 0;
}

.submit-answer-btn:hover {
  background: #0945a0;
}

.submit-answer-btn:disabled {
  opacity: .6;
  cursor: not-allowed;
}

.show-answer-btn {
  background: #8a5a00;
  font-size: 13px;
  padding: 0 14px;
  margin-top: 0;
}

.show-answer-btn:hover {
  background: #704800;
}

.show-answer-btn:disabled {
  opacity: .6;
  cursor: not-allowed;
}

.generated-answer-box {
  margin-top: 12px;
  display: none;
}

.generated-answer-box.visible {
  display: block;
}

.assessment-box {
  margin-top: 12px;
  border: 1px solid #e0e0e0;
  border-radius: 12px;
  padding: 14px;
  background: #fafafa;
  display: none;
}

.assessment-box.visible {
  display: block;
}

.assessment-box p {
  margin: 0 0 10px;
  line-height: 1.6;
}

.assessment-box p:last-child {
  margin-bottom: 0;
}

.assessment-box strong {
  font-weight: 650;
}

.new-problem-btn {
  background: #555;
  font-size: 13px;
  padding: 0 14px;
  margin-top: 0;
}

.new-problem-btn:hover {
  background: #444;
}

.debug-box {
  margin-top: 16px;
  border: 1px solid #d6d6d6;
  border-radius: 12px;
  background: #fafafa;
}

.debug-box summary {
  cursor: pointer;
  padding: 10px 14px;
  font-size: 13px;
  color: #555;
}

.debug-log {
  margin: 0;
  padding: 0 14px 14px;
  max-height: 220px;
  overflow: auto;
  white-space: pre-wrap;
  word-break: break-word;
  font-size: 12px;
  line-height: 1.5;
  color: #333;
}