/* Site-level visual enhancements kept outside the Butterfly theme. */
:root {
  --sail-accent: #2563eb;
  --sail-accent-soft: rgba(37, 99, 235, 0.1);
  --sail-cyan: #0891b2;
  --sail-surface: rgba(255, 255, 255, 0.88);
  --sail-surface-strong: rgba(255, 255, 255, 0.96);
  --sail-border: rgba(37, 99, 235, 0.12);
  --sail-shadow: 0 18px 45px rgba(30, 64, 175, 0.08);
  --sail-radius: 18px;
}

[data-theme='dark'] {
  --sail-accent: #7dd3fc;
  --sail-accent-soft: rgba(56, 189, 248, 0.12);
  --sail-cyan: #67e8f9;
  --sail-surface: rgba(20, 28, 45, 0.88);
  --sail-surface-strong: rgba(17, 24, 39, 0.96);
  --sail-border: rgba(125, 211, 252, 0.14);
  --sail-shadow: 0 18px 45px rgba(0, 0, 0, 0.24);
}

#web_bg {
  background:
    radial-gradient(circle at 12% 12%, rgba(37, 99, 235, 0.12), transparent 32%),
    radial-gradient(circle at 88% 18%, rgba(8, 145, 178, 0.1), transparent 30%),
    linear-gradient(135deg, #f8fafc 0%, #eef6ff 48%, #f5f3ff 100%);
  background-attachment: fixed;
}

[data-theme='dark'] #web_bg {
  background:
    radial-gradient(circle at 12% 12%, rgba(37, 99, 235, 0.2), transparent 34%),
    radial-gradient(circle at 88% 18%, rgba(8, 145, 178, 0.16), transparent 32%),
    linear-gradient(135deg, #0f172a 0%, #111827 52%, #172033 100%);
}

#recent-posts > .recent-post-item,
.layout > div:first-child:not(.recent-posts),
.card-widget {
  border: 1px solid var(--sail-border);
  border-radius: var(--sail-radius);
  background: var(--sail-surface);
  box-shadow: var(--sail-shadow);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
}

#recent-posts > .recent-post-item {
  overflow: hidden;
  transition: transform 0.25s ease, box-shadow 0.25s ease, border-color 0.25s ease;
}

#recent-posts > .recent-post-item:hover {
  transform: translateY(-4px);
  border-color: rgba(37, 99, 235, 0.28);
  box-shadow: 0 24px 55px rgba(30, 64, 175, 0.14);
}

#recent-posts .recent-post-info .article-title {
  font-weight: 720;
  letter-spacing: -0.015em;
}

#recent-posts .article-meta-wrap,
#post-info .post-meta {
  opacity: 0.82;
}

.card-widget .item-headline {
  color: var(--sail-accent);
  font-weight: 700;
}

.card-info-avatar .author-info__name {
  letter-spacing: 0.02em;
}

.avatar-img img {
  border: 3px solid rgba(255, 255, 255, 0.75);
  box-shadow: 0 10px 24px rgba(30, 64, 175, 0.18);
}

#article-container {
  font-size: 16px;
  line-height: 1.86;
  letter-spacing: 0.008em;
}

#article-container h2 {
  margin-top: 2.3em;
  padding: 0.48em 0.72em;
  border-left: 4px solid var(--sail-accent);
  border-radius: 0 10px 10px 0;
  background: linear-gradient(90deg, var(--sail-accent-soft), transparent 78%);
  font-size: 1.48em;
}

#article-container h3 {
  margin-top: 1.8em;
  color: var(--sail-accent);
  font-size: 1.18em;
}

#article-container h1::before,
#article-container h2::before,
#article-container h3::before,
#article-container h4::before,
#article-container h5::before,
#article-container h6::before {
  display: none;
}

#article-container blockquote {
  margin: 1.6em 0;
  padding: 1em 1.2em;
  border-left: 4px solid var(--sail-cyan);
  border-radius: 10px;
  background: var(--sail-accent-soft);
}

#article-container code:not(pre code) {
  margin: 0 0.12em;
  padding: 0.18em 0.42em;
  border: 1px solid var(--sail-border);
  border-radius: 6px;
  color: #be123c;
  background: var(--sail-surface-strong);
}

[data-theme='dark'] #article-container code:not(pre code) {
  color: #fda4af;
}

#article-container .highlight,
#article-container pre {
  border-radius: 13px;
  box-shadow: 0 12px 28px rgba(15, 23, 42, 0.12);
}

#article-container table {
  width: 100%;
  border: 1px solid var(--sail-border);
  border-radius: 12px;
  background: var(--sail-surface-strong);
  box-shadow: 0 10px 26px rgba(30, 64, 175, 0.06);
}

#article-container table thead {
  background: var(--sail-accent-soft);
}

#article-container table tr:hover td {
  background: rgba(37, 99, 235, 0.045);
}

#article-container .mermaid-wrap {
  margin: 1.8em 0;
  padding: 1.2em;
  overflow-x: auto;
  border: 1px solid var(--sail-border);
  border-radius: 14px;
  background: var(--sail-surface-strong);
  box-shadow: 0 12px 30px rgba(30, 64, 175, 0.08);
}

#article-container .mermaid-wrap svg {
  display: block;
  max-width: 100%;
  margin: 0 auto;
}

.tag-cloud-list a {
  display: inline-flex;
  align-items: center;
  min-height: 2.3em;
  margin: 0.35em;
  padding: 0.28em 0.72em;
  border: 1px solid var(--sail-border);
  border-radius: 999px;
  background: var(--sail-surface-strong);
  box-shadow: 0 6px 18px rgba(30, 64, 175, 0.06);
  transition: transform 0.2s ease, border-color 0.2s ease;
}

.tag-cloud-list a:hover {
  transform: translateY(-2px);
  border-color: var(--sail-accent);
}

.category-list .category-list-item {
  margin: 0.55em 0;
  padding: 0.72em 0.9em;
  border: 1px solid var(--sail-border);
  border-radius: 12px;
  background: var(--sail-surface-strong);
}

.post-copyright {
  border-radius: 14px;
  background: var(--sail-accent-soft);
}

#page-header #site-title,
#page-header #site-subtitle,
#page-header .page-title {
  text-shadow: 0 4px 18px rgba(15, 23, 42, 0.42);
}

#article-container .article-hero {
  margin: 1.8em 0 2.2em;
  overflow: hidden;
  border: 1px solid var(--sail-border);
  border-radius: var(--sail-radius);
  background: var(--sail-surface-strong);
  box-shadow: var(--sail-shadow);
}

#article-container .article-hero img {
  display: block;
  width: 100%;
  aspect-ratio: 16 / 9;
  object-fit: cover;
}

#article-container .article-hero figcaption {
  padding: 0.8em 1.1em;
  color: var(--font-color);
  font-size: 0.88em;
  line-height: 1.6;
  text-align: center;
  opacity: 0.78;
}

.music-studio {
  --music-ink: #e8f0ff;
  --music-muted: #a9b8d4;
  --music-panel: rgba(11, 20, 40, 0.86);
  --music-line: rgba(148, 189, 255, 0.18);
  margin: 2em 0;
  padding: clamp(1.1rem, 3vw, 2rem);
  overflow: hidden;
  border: 1px solid var(--music-line);
  border-radius: 24px;
  color: var(--music-ink);
  background:
    radial-gradient(circle at 10% 0%, rgba(59, 130, 246, 0.22), transparent 34%),
    radial-gradient(circle at 92% 8%, rgba(168, 85, 247, 0.18), transparent 32%),
    linear-gradient(145deg, #0b1428, #121b33 58%, #17152d);
  box-shadow: 0 28px 70px rgba(15, 23, 42, 0.3);
}

.music-studio-header {
  display: flex;
  align-items: flex-end;
  justify-content: space-between;
  gap: 1.5rem;
  margin-bottom: 1.4rem;
}

.music-studio-header h2 {
  margin: 0.18em 0 0.2em !important;
  padding: 0 !important;
  border: 0 !important;
  color: #fff !important;
  font-size: clamp(1.45rem, 3vw, 2rem) !important;
  background: none !important;
}

.music-studio-header h2::before {
  display: none !important;
}

.music-studio-header p {
  margin: 0;
  color: var(--music-muted);
}

.music-studio-kicker {
  color: #7dd3fc;
  font-size: 0.72rem;
  font-weight: 750;
  letter-spacing: 0.16em;
}

.music-volume-control {
  display: flex;
  align-items: center;
  gap: 0.65rem;
  min-width: 180px;
  color: var(--music-muted);
  font-size: 0.84rem;
}

.music-volume {
  width: 120px;
  accent-color: #60a5fa;
}

.music-track-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 1rem;
}

.music-track-card {
  --track-accent: #60a5fa;
  --track-progress: 0%;
  position: relative;
  display: flex;
  min-height: 330px;
  padding: 1.15rem;
  overflow: hidden;
  border: 1px solid var(--music-line);
  border-radius: 18px;
  flex-direction: column;
  background: rgba(255, 255, 255, 0.055);
  transition: transform 0.24s ease, border-color 0.24s ease, background 0.24s ease;
}

.music-track-card:hover {
  transform: translateY(-4px);
  border-color: color-mix(in srgb, var(--track-accent) 60%, transparent);
  background: rgba(255, 255, 255, 0.085);
}

.music-track-rain {
  --track-accent: #f0abfc;
}

.music-track-voyage {
  --track-accent: #5eead4;
}

.music-track-visual {
  display: flex;
  height: 72px;
  margin-bottom: 1rem;
  align-items: flex-end;
  gap: 8px;
}

.music-track-visual i {
  width: 12%;
  height: 42%;
  border-radius: 999px;
  background: linear-gradient(to top, var(--track-accent), rgba(255, 255, 255, 0.86));
  box-shadow: 0 0 20px color-mix(in srgb, var(--track-accent) 36%, transparent);
  animation: music-idle-wave 2.8s ease-in-out infinite alternate;
}

.music-track-visual i:nth-child(2) {
  height: 78%;
  animation-delay: -1.1s;
}

.music-track-visual i:nth-child(3) {
  height: 55%;
  animation-delay: -0.5s;
}

.music-track-visual i:nth-child(4) {
  height: 92%;
  animation-delay: -1.7s;
}

.music-track-visual i:nth-child(5) {
  height: 62%;
  animation-delay: -0.8s;
}

.music-track-meta {
  display: flex;
  justify-content: space-between;
  color: var(--music-muted);
  font-size: 0.72rem;
  letter-spacing: 0.04em;
}

.music-track-card h3 {
  margin: 0.45rem 0 0.4rem !important;
  color: #fff !important;
  font-size: 1.25rem !important;
}

.music-track-card h3::before {
  display: none !important;
}

.music-track-card p {
  margin: 0 0 1rem;
  color: var(--music-muted);
  font-size: 0.88rem;
  line-height: 1.7;
}

.music-play {
  display: inline-flex;
  min-height: 42px;
  margin-top: auto;
  padding: 0.65rem 1rem;
  border: 1px solid color-mix(in srgb, var(--track-accent) 48%, transparent);
  border-radius: 999px;
  align-items: center;
  justify-content: center;
  gap: 0.55rem;
  color: #fff;
  background: color-mix(in srgb, var(--track-accent) 22%, transparent);
  cursor: pointer;
  transition: background 0.2s ease, transform 0.2s ease;
}

.music-play:hover,
.music-play.is-playing {
  background: color-mix(in srgb, var(--track-accent) 42%, transparent);
}

.music-play:active {
  transform: scale(0.98);
}

.music-play.is-playing .music-button-icon {
  font-size: 0;
}

.music-play.is-playing .music-button-icon::after {
  content: '■';
  font-size: 0.8rem;
}

.music-track-progress {
  height: 3px;
  margin-top: 0.8rem;
  overflow: hidden;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.1);
}

.music-track-progress span {
  display: block;
  width: var(--track-progress);
  height: 100%;
  border-radius: inherit;
  background: var(--track-accent);
  transition: width 0.1s linear;
}

.music-studio-note {
  margin: 1rem 0 0 !important;
  color: var(--music-muted);
  font-size: 0.78rem;
  text-align: center;
}

@keyframes music-idle-wave {
  from { transform: scaleY(0.7); opacity: 0.68; }
  to { transform: scaleY(1); opacity: 1; }
}

.algorithm-roadmap {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1.2rem;
  margin: 2rem 0 2.4rem;
}

.algorithm-level-card {
  --algorithm-accent: #2563eb;
  position: relative;
  padding: 1.5rem;
  overflow: hidden;
  border: 1px solid var(--sail-border);
  border-radius: var(--sail-radius);
  background:
    radial-gradient(circle at 100% 0%, color-mix(in srgb, var(--algorithm-accent) 16%, transparent), transparent 42%),
    var(--sail-surface-strong);
  box-shadow: var(--sail-shadow);
}

.algorithm-level-card-advanced {
  --algorithm-accent: #7c3aed;
}

.algorithm-level-number {
  position: absolute;
  top: -0.16em;
  right: 0.12em;
  color: color-mix(in srgb, var(--algorithm-accent) 9%, transparent);
  font-size: 6.5rem;
  font-weight: 850;
  line-height: 1;
  pointer-events: none;
}

.algorithm-level-label {
  color: var(--algorithm-accent);
  font-size: 0.72rem;
  font-weight: 760;
  letter-spacing: 0.12em;
}

#article-container .algorithm-level-card h2 {
  position: relative;
  margin: 0.55rem 0 0.7rem;
  padding: 0;
  border: 0;
  color: var(--font-color);
  font-size: 1.35rem;
  background: none;
}

.algorithm-level-card > p {
  position: relative;
  min-height: 5.2em;
  margin: 0 0 1rem;
  color: var(--font-color);
  font-size: 0.9rem;
  line-height: 1.75;
  opacity: 0.82;
}

.algorithm-level-card ul {
  margin: 0 0 1.1rem !important;
  padding: 0 !important;
  list-style: none !important;
}

.algorithm-level-card li {
  display: flex;
  padding: 0.65rem 0;
  border-bottom: 1px dashed var(--sail-border);
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
}

.algorithm-level-card li a {
  color: var(--font-color);
  font-weight: 650;
}

.algorithm-level-card li span {
  flex: 0 0 auto;
  color: var(--algorithm-accent);
  font-size: 0.76rem;
}

.algorithm-reading-link {
  display: inline-flex;
  padding: 0.62rem 0.9rem;
  border: 1px solid color-mix(in srgb, var(--algorithm-accent) 35%, transparent);
  border-radius: 999px;
  color: var(--algorithm-accent) !important;
  font-size: 0.86rem;
  font-weight: 680;
  background: color-mix(in srgb, var(--algorithm-accent) 8%, transparent);
  transition: transform 0.2s ease, background 0.2s ease;
}

.algorithm-reading-link:hover {
  transform: translateY(-2px);
  background: color-mix(in srgb, var(--algorithm-accent) 15%, transparent);
}

@media (max-width: 768px) {
  :root {
    --sail-radius: 14px;
  }

  #article-container {
    font-size: 15.5px;
    line-height: 1.8;
  }

  #article-container h2 {
    font-size: 1.34em;
  }

  #article-container .mermaid-wrap {
    padding: 0.7em;
  }

  #article-container .article-hero {
    margin: 1.35em 0 1.7em;
  }

  .music-studio-header {
    align-items: flex-start;
    flex-direction: column;
  }

  .music-track-grid {
    grid-template-columns: 1fr;
  }

  .music-track-card {
    min-height: 290px;
  }

  .algorithm-roadmap {
    grid-template-columns: 1fr;
  }

  .algorithm-level-card > p {
    min-height: 0;
  }
}

@media (prefers-reduced-motion: reduce) {
  #recent-posts > .recent-post-item,
  .tag-cloud-list a,
  .music-track-card,
  .music-play,
  .algorithm-reading-link {
    transition: none;
  }

  .music-track-visual i {
    animation: none;
  }
}