/* Papers — Hub + Markdown Viewer */

/* ══════════════════════════════════
   HUB
   ══════════════════════════════════ */

.papers-main {
  position: relative;
  z-index: 1;
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 2rem;
  padding: 2rem 1.5rem 3rem;
  max-width: 680px;
  margin: 0 auto;
  width: 100%;
}

.papers-hero {
  text-align: center;
}

.papers-title {
  margin: 0 0 0.5rem;
  font-family: var(--w3-font-display);
  font-size: clamp(1.8rem, 5vw, 2.5rem);
  font-weight: 600;
  letter-spacing: -0.02em;
}

.papers-subtitle {
  margin: 0 0 0.5rem;
  font-size: 0.95rem;
  color: var(--w3-text);
  font-weight: 300;
  line-height: 1.5;
}

.papers-meta {
  margin: 0;
  font-size: 0.75rem;
  color: var(--w3-muted);
  font-weight: 400;
  letter-spacing: 0.06em;
}

/* Paper cards */
.papers-chain {
  width: 100%;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0;
}

.paper-card {
  width: 100%;
  padding: 1.75rem 2rem;
  border-radius: 20px;
  border: 1.5px solid rgba(255, 255, 255, 0.08);
  position: relative;
  overflow: hidden;
  transition: border-color 0.35s;
}

.paper-card:hover {
  border-color: color-mix(in srgb, var(--paper-color) 40%, transparent);
}

.paper-card::before {
  content: '';
  position: absolute;
  inset: 0;
  border-radius: 20px;
  background: radial-gradient(ellipse at 0% 0%, var(--paper-color), transparent 60%);
  opacity: 0.04;
}

.paper-card-header {
  display: flex;
  align-items: center;
  gap: 1rem;
  margin-bottom: 1rem;
}

.paper-icon {
  width: 44px;
  height: 44px;
  flex-shrink: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 12px;
  background: color-mix(in srgb, var(--paper-color) 12%, transparent);
  border: 1px solid color-mix(in srgb, var(--paper-color) 25%, transparent);
  padding: 9px;
}

.paper-icon svg {
  width: 100%;
  height: 100%;
  stroke: var(--paper-color);
}

.paper-name {
  margin: 0;
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--w3-text);
}

.paper-desc {
  margin: 0.15rem 0 0;
  font-size: 0.75rem;
  color: var(--w3-muted);
  font-weight: 300;
}

.paper-summary {
  margin: 0 0 1.25rem;
  font-size: 0.9rem;
  color: var(--w3-text);
  font-weight: 300;
  line-height: 1.65;
  position: relative;
  z-index: 1;
}

/* Language buttons */
.paper-langs {
  display: flex;
  gap: 0.6rem;
  flex-wrap: wrap;
  position: relative;
  z-index: 1;
}

.lang-btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.5rem 1rem;
  border-radius: 10px;
  font-size: 0.82rem;
  font-weight: 500;
  color: var(--w3-text);
  text-decoration: none;
  background: rgba(255, 255, 255, 0.04);
  border: 1px solid rgba(255, 255, 255, 0.1);
  transition: all 0.3s;
}

.lang-btn:hover {
  background: color-mix(in srgb, var(--paper-color) 12%, transparent);
  border-color: color-mix(in srgb, var(--paper-color) 35%, transparent);
  transform: translateY(-1px);
  box-shadow: 0 4px 16px color-mix(in srgb, var(--paper-color) 15%, transparent);
}

.lang-btn.lang-soon {
  opacity: 0.4;
  cursor: default;
  pointer-events: none;
}

.lang-flag {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 24px;
  height: 24px;
  border-radius: 6px;
  font-size: 0.6rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  background: color-mix(in srgb, var(--paper-color) 15%, transparent);
  color: var(--paper-color);
}

/* Connector */
.paper-connector {
  width: 3px;
  height: 28px;
  border-radius: 3px;
  background: rgba(255, 255, 255, 0.06);
  position: relative;
  overflow: hidden;
  flex-shrink: 0;
}

.paper-connector-pulse {
  position: absolute;
  left: 0;
  top: -100%;
  width: 100%;
  height: 100%;
  border-radius: 3px;
  background: linear-gradient(180deg, transparent, var(--w3-purple), transparent);
  animation: paperFlow 2.5s ease-in-out infinite;
}

@keyframes paperFlow {
  0% { top: -100%; opacity: 0; }
  40% { opacity: 1; }
  100% { top: 100%; opacity: 0; }
}

/* ══════════════════════════════════
   VIEWER
   ══════════════════════════════════ */

.viewer-main {
  position: relative;
  z-index: 1;
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: 1.5rem 1.5rem 3rem;
  max-width: 820px;
  margin: 0 auto;
  width: 100%;
}

.viewer-card {
  width: 100%;
  padding: 2.5rem 2.5rem;
  border-radius: 24px;
  min-height: 300px;
}

/* Loading */
.viewer-loading {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 1rem;
  padding: 3rem 0;
  color: var(--w3-muted);
  font-size: 0.9rem;
}

.viewer-spinner {
  width: 32px;
  height: 32px;
  border: 2px solid rgba(192, 132, 252, 0.2);
  border-top-color: var(--w3-purple);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}

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

/* Markdown rendered content */
.viewer-content {
  color: var(--w3-text);
  font-weight: 300;
  line-height: 1.8;
  font-size: 0.95rem;
}

.viewer-content h1 {
  font-family: var(--w3-font-display);
  font-size: 1.8rem;
  font-weight: 600;
  margin: 2.5rem 0 1rem;
  background-image: var(--w3-gradient);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
}

.viewer-content h1:first-child {
  margin-top: 0;
}

.viewer-content h2 {
  font-size: 1.15rem;
  font-weight: 600;
  margin: 2rem 0 0.75rem;
  color: var(--w3-text);
  padding-bottom: 0.4rem;
  border-bottom: 1px solid rgba(192, 132, 252, 0.12);
}

.viewer-content h3 {
  font-size: 0.95rem;
  font-weight: 600;
  margin: 1.5rem 0 0.5rem;
  color: var(--w3-purple);
}

.viewer-content h4 {
  font-size: 0.85rem;
  font-weight: 600;
  margin: 1.25rem 0 0.4rem;
  color: var(--w3-muted);
  text-transform: uppercase;
  letter-spacing: 0.08em;
}

.viewer-content p {
  margin: 0 0 1rem;
}

.viewer-content a {
  color: var(--w3-purple);
  text-decoration: none;
  border-bottom: 1px solid rgba(192, 132, 252, 0.25);
  transition: color 0.2s, border-color 0.2s;
}

.viewer-content a:hover {
  color: var(--w3-teal);
  border-bottom-color: var(--w3-teal);
}

.viewer-content strong {
  font-weight: 600;
  color: var(--w3-text);
}

.viewer-content ul,
.viewer-content ol {
  padding-left: 1.5rem;
  margin: 0 0 1rem;
}

.viewer-content li {
  margin-bottom: 0.35rem;
}

.viewer-content li::marker {
  color: var(--w3-purple);
}

.viewer-content blockquote {
  margin: 1.25rem 0;
  padding: 1rem 1.5rem;
  border-left: 3px solid var(--w3-purple);
  border-radius: 0 12px 12px 0;
  background: rgba(192, 132, 252, 0.05);
  font-style: italic;
  color: var(--w3-text);
}

.viewer-content code {
  font-family: 'Courier New', monospace;
  font-size: 0.85em;
  padding: 0.15em 0.4em;
  border-radius: 4px;
  background: rgba(192, 132, 252, 0.1);
  color: var(--w3-purple);
}

.viewer-content pre {
  margin: 1rem 0;
  padding: 1.25rem;
  border-radius: 14px;
  background: rgba(0, 0, 0, 0.3);
  border: 1px solid rgba(192, 132, 252, 0.1);
  overflow-x: auto;
  font-size: 0.82rem;
  line-height: 1.6;
}

.viewer-content pre code {
  background: none;
  padding: 0;
  color: var(--w3-text);
  font-size: inherit;
}

.viewer-content table {
  width: 100%;
  border-collapse: collapse;
  margin: 1rem 0;
  font-size: 0.88rem;
}

.viewer-content th {
  text-align: left;
  padding: 0.6rem 0.75rem;
  font-weight: 600;
  color: var(--w3-text);
  border-bottom: 2px solid rgba(192, 132, 252, 0.2);
  font-size: 0.8rem;
  letter-spacing: 0.04em;
}

.viewer-content td {
  padding: 0.55rem 0.75rem;
  border-bottom: 1px solid rgba(255, 255, 255, 0.05);
  vertical-align: top;
}

.viewer-content tr:hover td {
  background: rgba(192, 132, 252, 0.03);
}

.viewer-content hr {
  border: none;
  height: 1px;
  background: linear-gradient(90deg, transparent, rgba(192, 132, 252, 0.2), transparent);
  margin: 2rem 0;
}

.viewer-content img {
  max-width: 100%;
  border-radius: 8px;
}

/* ══════════════════════════════════
   RESPONSIVE
   ══════════════════════════════════ */

@media (max-width: 600px) {
  .papers-main {
    padding: 1rem 1rem 2rem;
  }

  .paper-card {
    padding: 1.5rem 1.25rem;
  }

  .viewer-main {
    padding: 1rem 0.75rem 2rem;
  }

  .viewer-card {
    padding: 1.5rem 1.25rem;
    border-radius: 18px;
  }

  .viewer-content h1 { font-size: 1.4rem; }
  .viewer-content h2 { font-size: 1.05rem; }

  .viewer-content pre {
    padding: 1rem;
    font-size: 0.75rem;
  }

  .viewer-content table {
    font-size: 0.78rem;
  }

  .viewer-content th,
  .viewer-content td {
    padding: 0.4rem 0.5rem;
  }
}