:root {
  --color-primary: #4F46E5;
  --color-bg: #FFFFFF;
  --color-bg-subtle: #F3F4F6;
  --color-text: #111827;
  --color-text-muted: #6B7280;
  --color-border: #E5E7EB;
  --color-error: #B91C1C;
  --color-error-bg: #FEF2F2;
  --radius: 10px;
  --font: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}

* {
  box-sizing: border-box;
}

html, body {
  margin: 0;
  padding: 0;
  background: var(--color-bg);
  color: var(--color-text);
  font-family: var(--font);
  line-height: 1.5;
  height: 100%;
}

body {
  display: flex;
  flex-direction: column;
  height: 100dvh;
  overflow: hidden;
}

.app-header {
  flex: none;
  padding: 20px 16px 12px;
  max-width: 720px;
  margin: 0 auto;
  width: 100%;
}

.app-header h1 {
  font-size: 1.5rem;
  margin: 0 0 6px;
}

.tagline {
  margin: 0;
  color: var(--color-text-muted);
  font-size: 0.9rem;
}

main {
  flex: 1;
  display: flex;
  flex-direction: column;
  justify-content: center;
  max-width: 720px;
  width: 100%;
  margin: 0 auto;
  padding: 0 16px 16px;
  min-height: 0;
  overflow: hidden;
}

#chat-view {
  display: flex;
  flex-direction: column;
  flex: 1;
  min-height: 0;
}

#chat-view[hidden] {
  display: none;
}

.panel {
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 32px 20px;
  text-align: center;
}

.dropzone {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 6px;
  cursor: pointer;
  border: 1.5px dashed var(--color-border);
  border-radius: var(--radius);
  padding: 28px 16px;
}

.dropzone:hover,
.dropzone:focus-visible {
  border-color: var(--color-primary);
}

.dropzone-title {
  font-weight: 600;
}

.dropzone-hint {
  font-size: 0.85rem;
  color: var(--color-text-muted);
}

.status-line {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  color: var(--color-text-muted);
  margin: 0;
}

.spinner {
  width: 16px;
  height: 16px;
  border: 2px solid var(--color-border);
  border-top-color: var(--color-primary);
  border-radius: 50%;
  animation: spin 0.7s linear infinite;
  flex-shrink: 0;
}

@keyframes spin {
  to { transform: rotate(360deg); }
}

.error-text {
  color: var(--color-error);
  font-size: 0.9rem;
  margin: 12px 0 0;
}

.doc-bar {
  flex: none;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: 10px 14px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  background: var(--color-bg-subtle);
  margin: 12px 0;
  flex-wrap: wrap;
}

.doc-info {
  display: flex;
  flex-direction: column;
  min-width: 0;
}

.doc-name {
  font-weight: 600;
  font-size: 0.9rem;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.doc-meta {
  font-size: 0.8rem;
  color: var(--color-text-muted);
}

.btn-primary,
.btn-secondary {
  font-family: inherit;
  font-size: 0.9rem;
  border-radius: 8px;
  padding: 8px 16px;
  cursor: pointer;
  border: 1px solid transparent;
}

.btn-primary {
  background: var(--color-primary);
  color: #fff;
  border-color: var(--color-primary);
}

.btn-primary:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

.btn-secondary {
  background: transparent;
  color: var(--color-text);
  border-color: var(--color-border);
  white-space: nowrap;
}

.btn-secondary:hover {
  border-color: var(--color-primary);
  color: var(--color-primary);
}

.messages {
  flex: 1;
  min-height: 0;
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  gap: 14px;
  padding: 8px 2px 16px;
}

.message {
  max-width: 85%;
  padding: 10px 14px;
  border-radius: var(--radius);
  font-size: 0.95rem;
  white-space: pre-wrap;
  word-wrap: break-word;
}

.message.user {
  align-self: flex-end;
  background: var(--color-primary);
  color: #fff;
  border-bottom-right-radius: 3px;
}

.message.assistant {
  align-self: flex-start;
  background: var(--color-bg-subtle);
  border-bottom-left-radius: 3px;
}

.message.error {
  align-self: flex-start;
  background: var(--color-error-bg);
  color: var(--color-error);
  border-bottom-left-radius: 3px;
}

.message-sources {
  align-self: flex-start;
  max-width: 85%;
  font-size: 0.85rem;
}

.message-sources summary {
  cursor: pointer;
  color: var(--color-text-muted);
  padding: 2px 0;
}

.source-item {
  padding: 8px 0;
  border-top: 1px solid var(--color-border);
}

.source-head {
  display: flex;
  justify-content: space-between;
  font-size: 0.8rem;
  margin-bottom: 3px;
}

.source-page {
  font-weight: 600;
}

.source-score {
  color: var(--color-text-muted);
}

.source-text {
  margin: 0;
  color: var(--color-text-muted);
  white-space: pre-wrap;
}

.ask-form {
  flex: none;
  background: var(--color-bg);
  display: flex;
  gap: 8px;
  padding: 10px 0 14px;
  border-top: 1px solid var(--color-border);
}

.question-input {
  flex: 1;
  font-family: inherit;
  font-size: 0.95rem;
  padding: 10px 12px;
  border: 1px solid var(--color-border);
  border-radius: 8px;
  resize: none;
  max-height: 120px;
}

.question-input:focus {
  outline: none;
  border-color: var(--color-primary);
}

@media (max-width: 420px) {
  .app-header h1 {
    font-size: 1.25rem;
  }
  .panel {
    padding: 24px 14px;
  }
}