:root {
  --yt-ink: var(--ink, #1a211e);
  --yt-soft: var(--ink-soft, #3a4540);
  --yt-line: var(--line, #c5d0c8);
  --yt-panel: color-mix(in srgb, var(--paper, #eef2ef) 88%, #dfe8e2);
  --yt-accent: #2c4a3e;
}

.yt-page {
  padding-bottom: 4rem;
}

.yt-hero h1 {
  font-family: var(--font-serif, 'Noto Serif SC', serif);
  font-weight: 500;
  letter-spacing: 0.04em;
}

.yt-hero > p {
  color: var(--yt-soft);
  max-width: 42rem;
}

.yt-cards {
  display: grid;
  gap: 1.25rem;
  margin-top: 1.75rem;
}

@media (min-width: 720px) {
  .yt-cards {
    grid-template-columns: 1fr 1fr;
  }
}

.yt-card {
  display: block;
  padding: 1.35rem 1.4rem 1.5rem;
  border: 1px solid var(--yt-line);
  background:
    linear-gradient(165deg, color-mix(in srgb, #fff 55%, transparent), transparent 55%),
    var(--yt-panel);
  text-decoration: none;
  color: inherit;
  transition: border-color 0.2s ease, transform 0.2s ease;
}

.yt-card:hover {
  border-color: var(--yt-accent);
  transform: translateY(-2px);
}

.yt-card h2 {
  margin: 0.35rem 0 0.5rem;
  font-family: var(--font-serif, 'Noto Serif SC', serif);
  font-size: 1.35rem;
  font-weight: 500;
}

.yt-card p {
  margin: 0;
  color: var(--yt-soft);
  font-size: 0.95rem;
  line-height: 1.55;
}

.yt-card .yt-kicker {
  margin: 0;
  font-size: 0.75rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--yt-accent);
  font-family: var(--font-sans, sans-serif);
}

.yt-back {
  display: inline-block;
  margin-bottom: 0.75rem;
  font-size: 0.9rem;
  color: var(--yt-soft);
  text-decoration: none;
}

.yt-back:hover {
  color: var(--yt-ink);
}

.yt-setup,
.yt-chat-wrap {
  margin-top: 1rem;
  border-top: 1px solid var(--yt-line);
  padding-top: 1.25rem;
  width: 100%;
}

.yt-label {
  display: block;
  margin: 0.75rem 0 0.35rem;
  font-size: 0.85rem;
  color: var(--yt-soft);
  font-family: var(--font-sans, sans-serif);
}

.yt-select,
.yt-input,
.yt-textarea {
  width: 100%;
  max-width: 40rem;
  padding: 0.55rem 0.7rem;
  border: 1px solid var(--yt-line);
  background: color-mix(in srgb, #fff 70%, var(--yt-panel));
  color: var(--yt-ink);
  font: inherit;
}

.yt-textarea {
  min-height: 4.5rem;
  resize: vertical;
}

.yt-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.6rem;
  margin-top: 0.85rem;
}

.yt-btn {
  appearance: none;
  border: 1px solid var(--yt-accent);
  background: var(--yt-accent);
  color: #f4f7f5;
  padding: 0.5rem 1rem;
  font: inherit;
  cursor: pointer;
}

.yt-btn:disabled {
  opacity: 0.55;
  cursor: not-allowed;
}

.yt-btn--ghost {
  background: transparent;
  color: var(--yt-ink);
  border-color: var(--yt-line);
}

.yt-msg {
  margin-top: 0.75rem;
  font-size: 0.9rem;
  color: var(--yt-soft);
  font-family: var(--font-sans, sans-serif);
}

.yt-msg--err {
  color: #8b2e2e;
}

.yt-chat {
  display: flex;
  flex-direction: column;
  gap: 1rem;
  width: 100%;
  max-width: none;
  margin: 1rem 0 1.25rem;
  min-height: 8rem;
}

.yt-bubble {
  padding: 1rem 1.15rem;
  border: 1px solid var(--yt-line);
  line-height: 1.75;
  white-space: pre-wrap;
  word-break: break-word;
  font-family: var(--font-serif, 'Songti SC', 'Noto Serif SC', serif);
  font-size: 1.05rem;
  font-weight: 500;
  color: var(--yt-ink);
}

.yt-bubble--assistant {
  background: color-mix(in srgb, #fff 62%, var(--yt-panel));
  border-left: 3px solid var(--yt-accent);
}

.yt-bubble--user {
  background: color-mix(in srgb, #fff 82%, var(--yt-panel));
  margin-left: clamp(0rem, 8vw, 4rem);
}

.yt-bubble-meta {
  display: block;
  margin-bottom: 0.4rem;
  font-size: 0.75rem;
  letter-spacing: 0.08em;
  color: var(--yt-soft);
  font-family: var(--font-sans, sans-serif);
  font-weight: 500;
}

.yt-composer {
  display: flex;
  flex-direction: column;
  gap: 0.55rem;
  width: 100%;
  max-width: none;
  margin-top: 0.25rem;
  padding: 1rem 0 0;
  border-top: 1px solid var(--yt-line);
  background: transparent;
  position: static;
}

.yt-composer .yt-textarea {
  max-width: none;
}

.yt-chips {
  display: flex;
  flex-wrap: wrap;
  gap: 0.45rem;
}

.yt-chip {
  appearance: none;
  border: 1px solid var(--yt-line);
  background: color-mix(in srgb, #fff 70%, var(--yt-panel));
  color: var(--yt-ink);
  padding: 0.35rem 0.7rem;
  font-size: 0.85rem;
  cursor: pointer;
  font-family: var(--font-sans, sans-serif);
}

.yt-chip:hover {
  border-color: var(--yt-accent);
}

.yt-hidden {
  display: none !important;
}

.yt-loading {
  display: flex;
  align-items: flex-start;
  gap: 0.85rem;
  max-width: 40rem;
  margin-bottom: 1rem;
  padding: 0.9rem 1rem;
  border: 1px solid var(--yt-line);
  background: color-mix(in srgb, #fff 55%, var(--yt-panel));
}

.yt-loading[hidden] {
  display: none !important;
}

.yt-loading-copy {
  min-width: 0;
}

.yt-loading-copy strong {
  display: block;
  font-family: var(--font-sans, sans-serif);
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--yt-ink);
}

.yt-loading-copy p {
  margin: 0.2rem 0 0;
  font-size: 0.88rem;
  color: var(--yt-soft);
  font-family: var(--font-sans, sans-serif);
  max-width: none;
}

.yt-spinner {
  flex: 0 0 auto;
  width: 1.15rem;
  height: 1.15rem;
  margin-top: 0.15rem;
  border: 2px solid color-mix(in srgb, var(--yt-accent) 25%, transparent);
  border-top-color: var(--yt-accent);
  border-radius: 50%;
  animation: yt-spin 0.7s linear infinite;
}

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

.yt-skeleton {
  max-width: 40rem;
}

.yt-skeleton[hidden] {
  display: none !important;
}

.yt-skel-label,
.yt-skel-bar,
.yt-skel-btn {
  border-radius: 2px;
  background: linear-gradient(
    90deg,
    color-mix(in srgb, var(--yt-line) 55%, transparent) 0%,
    color-mix(in srgb, #fff 70%, var(--yt-panel)) 45%,
    color-mix(in srgb, var(--yt-line) 55%, transparent) 100%
  );
  background-size: 200% 100%;
  animation: yt-shimmer 1.2s ease-in-out infinite;
}

.yt-skel-label {
  width: 5.5rem;
  height: 0.7rem;
  margin: 0.85rem 0 0.45rem;
}

.yt-skel-label:first-child {
  margin-top: 0;
}

.yt-skel-bar {
  width: 100%;
  height: 2.4rem;
}

.yt-skel-btn {
  width: 6.5rem;
  height: 2.2rem;
  margin-top: 1rem;
}

@keyframes yt-shimmer {
  0% {
    background-position: 100% 0;
  }
  100% {
    background-position: -100% 0;
  }
}

.yt-setup.is-loading .yt-fields {
  display: none !important;
}

.yt-select:disabled,
.yt-btn:disabled {
  opacity: 0.55;
  cursor: wait;
}

/* 进入对话后收紧页头，把宽度留给气泡 */
.yt-page.is-chatting .yt-hero > h1 {
  font-size: 1.45rem;
  margin-bottom: 0.35rem;
}

.yt-page.is-chatting .yt-hero > p:not(.yt-msg):not(.group-label) {
  display: none;
}

@media (min-width: 900px) {
  .yt-page.is-chatting .yt-bubble {
    max-width: 58rem;
  }

  .yt-page.is-chatting .yt-bubble--user {
    margin-left: 3rem;
  }
}