/* ==============================================================================
   paper.css — Interactive project-page styles (VGGT-style layout)
   Loaded only by pages using `layout: paper`. Reuses the CSS variables
   defined in main.css (--bg, --accent, --border, etc.)
   ============================================================================== */

.paper-main {
  max-width: 1140px;
  margin: 0 auto;
  padding: 2.75rem 1.5rem 5rem;
}

/* === Hero === */
.paper-hero {
  text-align: center;
  padding-bottom: 2.25rem;
  margin-bottom: 2.75rem;
  border-bottom: 1px solid var(--border);
}
.paper-venue-badge {
  display: inline-block;
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--accent);
  background: var(--accent-light);
  border: 1px solid var(--accent);
  border-radius: 100px;
  padding: 0.2rem 0.85rem;
  margin-bottom: 1rem;
}
.paper-hero h1 {
  font-size: clamp(1.6rem, 3.2vw, 2.35rem);
  font-weight: 800;
  letter-spacing: -0.02em;
  line-height: 1.25;
  max-width: 42rem;
  margin: 0 auto 1.1rem;
}
.paper-subtitle {
  font-size: clamp(1rem, 1.6vw, 1.25rem);
  font-weight: 500;
  color: var(--text-muted);
  max-width: 42rem;
  margin: -0.5rem auto 1.1rem;
}
.paper-authors {
  font-size: 1rem;
  color: var(--text);
  margin-bottom: 0.35rem;
}
.paper-authors a { font-weight: 600; }
.paper-authors sup { font-size: 0.65em; color: var(--text-muted); margin-left: 1px; }
.paper-affiliations {
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-bottom: 1.5rem;
}
.paper-affiliations sup { margin-right: 2px; }

.paper-links {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 0.6rem;
}
.paper-btn {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  padding: 0.55rem 1.15rem;
  border-radius: 100px;
  border: 1px solid var(--border);
  font-weight: 600;
  font-size: 0.88rem;
  color: var(--text);
  background: var(--bg);
  transition: border-color 0.15s, color 0.15s, background 0.15s, transform 0.15s;
}
.paper-btn:hover {
  border-color: var(--accent);
  color: var(--accent);
  background: var(--accent-light);
  text-decoration: none;
  transform: translateY(-1px);
}
.paper-btn.primary { background: var(--text); color: #fff; border-color: var(--text); }
.paper-btn.primary:hover { background: var(--accent); border-color: var(--accent); color: #fff; }
.paper-btn.disabled {
  cursor: not-allowed;
  color: var(--text-muted);
  opacity: 0.6;
}
.paper-btn.disabled:hover {
  border-color: var(--border);
  color: var(--text-muted);
  background: var(--bg);
  transform: none;
}

/* === Repeated title/authors block below the fullscreen video hero ===
   Same content as .paper-hero, but given more room to breathe since it
   sits in its own section rather than sharing the screen with a video. */
.paper-hero-repeat {
  max-width: 56rem;
  margin-left: auto;
  margin-right: auto;
}
.paper-hero-repeat h1 {
  font-size: clamp(2rem, 4vw, 2.9rem);
  max-width: none;
}
.paper-hero-repeat .paper-subtitle {
  font-size: clamp(1.05rem, 1.8vw, 1.35rem);
  max-width: none;
}
.paper-hero-repeat .paper-authors { font-size: 1.15rem; }
.paper-hero-repeat .paper-affiliations { font-size: 1.1rem; }
.paper-hero-repeat .paper-venue-badge { margin-bottom: 1.5rem; }
.paper-hero-repeat .paper-btn {
  padding: 0.65rem 1.35rem;
  font-size: 0.95rem;
}

/* === Fullscreen video hero (alternative to .paper-hero) === */
.paper-main:has(> .paper-hero-video) { padding-top: 0; }
.paper-hero-video {
  position: relative;
  width: 100vw;
  margin-left: calc(50% - 50vw);
  margin-right: calc(50% - 50vw);
  margin-top: 0;
  height: calc(100vh - 3.25rem);
  min-height: 420px;
  overflow: hidden;
  background: #000;
  display: flex;
  align-items: flex-start;
  justify-content: flex-start;
  text-align: left;
  margin-bottom: 2.75rem;
}
.paper-hero-video-bg {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  z-index: 0;
}
.paper-hero-video::after {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(to bottom, rgba(0,0,0,0.45) 0%, rgba(0,0,0,0.15) 35%, rgba(0,0,0,0.55) 100%);
  z-index: 1;
}
.paper-hero-video-overlay {
  position: relative;
  z-index: 2;
  color: #fff;
  padding: 3rem 2rem 1.5rem;
  max-width: 46rem;
  width: 100%;
  box-sizing: border-box;
}
.paper-hero-video-overlay .paper-venue-badge {
  background: rgba(255, 255, 255, 0.12);
  border-color: rgba(255, 255, 255, 0.5);
  color: #fff;
  backdrop-filter: blur(6px);
}
.paper-hero-video-overlay h1 {
  font-size: clamp(1.9rem, 4.2vw, 3rem);
  font-weight: 800;
  letter-spacing: -0.02em;
  line-height: 1.2;
  margin: 0 0 0.5rem;
  text-shadow: 0 2px 24px rgba(0,0,0,0.55);
}
.paper-hero-video-overlay .paper-subtitle {
  color: rgba(255, 255, 255, 0.88);
  max-width: none;
  margin: 0 0 1.1rem;
  text-shadow: 0 1px 14px rgba(0,0,0,0.6);
}
.paper-hero-video-overlay .paper-links { justify-content: flex-start; }
.paper-hero-video-overlay .paper-authors {
  color: #fff;
  font-size: 1rem;
  margin-bottom: 0.35rem;
  text-shadow: 0 1px 12px rgba(0,0,0,0.6);
}
.paper-hero-video-overlay .paper-authors a { color: #fff; font-weight: 600; }
.paper-hero-video-overlay .paper-affiliations {
  color: rgba(255, 255, 255, 0.8);
  font-size: 0.85rem;
  margin-bottom: 1.5rem;
  text-shadow: 0 1px 12px rgba(0,0,0,0.6);
}
.paper-hero-video-overlay .paper-btn {
  background: rgba(255, 255, 255, 0.1);
  border-color: rgba(255, 255, 255, 0.5);
  color: #fff;
  backdrop-filter: blur(6px);
}
.paper-hero-video-overlay .paper-btn:hover {
  background: rgba(255, 255, 255, 0.22);
  border-color: #fff;
  color: #fff;
}
.paper-hero-video-overlay .paper-btn.primary {
  background: #fff;
  color: #111;
  border-color: #fff;
}
.paper-hero-video-overlay .paper-btn.primary:hover { background: var(--accent); color: #fff; border-color: var(--accent); }
.paper-hero-video-overlay .paper-btn.disabled { color: rgba(255,255,255,0.55); border-color: rgba(255,255,255,0.3); }

.paper-hero-video-scroll {
  position: absolute;
  left: 50%;
  bottom: 1.75rem;
  transform: translateX(-50%);
  z-index: 2;
  color: rgba(255, 255, 255, 0.85);
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 0.03em;
  text-transform: uppercase;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.3rem;
  text-shadow: 0 1px 10px rgba(0,0,0,0.6);
  animation: paper-hero-scroll-bounce 1.8s ease-in-out infinite;
}
@keyframes paper-hero-scroll-bounce {
  0%, 100% { transform: translate(-50%, 0); }
  50% { transform: translate(-50%, 6px); }
}
@media (max-width: 640px) {
  .paper-hero-video { height: 100vh; }
}

/* === Generic section (wraps main.css .section/.section-title at paper width) === */
.paper-section { margin-bottom: 3.5rem; }
.paper-section p { color: var(--text); }
.paper-lead {
  font-size: 1rem;
  line-height: 1.7;
  max-width: none;
  text-align: justify;
  text-justify: inter-word;
  hyphens: auto;
}

/* === Takeaways (keyword pills) === */
.paper-keywords {
  display: flex;
  flex-wrap: wrap;
  gap: 0.6rem;
}
.paper-keyword {
  display: inline-flex;
  align-items: center;
  background: var(--accent-light);
  color: var(--accent-dark);
  border: 1px solid var(--accent);
  border-radius: 100px;
  padding: 0.4rem 1.1rem;
  font-size: 0.95rem;
  font-weight: 700;
  letter-spacing: -0.01em;
}

/* === Teaser / video === */

/* Break out of .paper-main's max-width so wide content (side-by-side
   teasers, the point-cloud viewer) can use more of the viewport. */
.paper-bleed {
  width: 100vw;
  margin-left: calc(50% - 50vw);
  margin-right: calc(50% - 50vw);
}
.paper-bleed-inner {
  max-width: 1500px;
  margin: 0 auto;
  padding: 0 1.5rem;
}
body.paper-page { overflow-x: hidden; }

.paper-media {
  border-radius: 12px;
  overflow: hidden;
  border: 1px solid var(--border);
  box-shadow: 0 10px 30px rgba(15, 23, 42, 0.07);
  margin-bottom: 0.75rem;
}
.paper-media video, .paper-media img { width: 100%; display: block; background: #000; }
.paper-caption {
  text-align: center;
  font-size: 1.05rem;
  color: var(--text-muted);
}

.paper-teaser-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1.5rem;
  margin-bottom: 0.75rem;
}
.paper-teaser-grid .paper-media { margin-bottom: 0.4rem; }
@media (max-width: 800px) {
  .paper-teaser-grid { grid-template-columns: 1fr; }
}

/* Hero + teaser videos fill the first screen (below the sticky nav) so the
   two videos read as "the page" until you scroll for the rest. Skipped
   below the grid's own 1-column breakpoint, where stacked full-height
   videos would just look cramped. */
@media (min-width: 801px) {
  .paper-above-fold {
    display: flex;
    flex-direction: column;
    min-height: calc(100vh - 3.25rem - 2.75rem);
  }
  .paper-above-fold .paper-hero { flex: 0 0 auto; }
  .paper-above-fold > .paper-bleed { flex: 1 1 auto; display: flex; margin-bottom: 0; }
  .paper-above-fold > .paper-bleed .paper-bleed-inner {
    flex: 1 1 auto;
    display: flex;
    flex-direction: column;
    width: 100%;
  }
  .paper-above-fold .paper-teaser-grid { flex: 1 1 auto; min-height: 0; }
  .paper-above-fold .paper-teaser-grid > div {
    display: flex;
    flex-direction: column;
    height: 100%;
    min-height: 0;
  }
  .paper-above-fold .paper-media,
  .paper-above-fold .paper-placeholder {
    flex: 1 1 auto;
    min-height: 0;
    margin-bottom: 0.5rem;
  }
  .paper-above-fold .paper-media video,
  .paper-above-fold .paper-media img {
    width: 100%;
    height: 100%;
    object-fit: cover;
  }
  .paper-above-fold .paper-caption { flex: 0 0 auto; }
}

.paper-placeholder {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  min-height: 220px;
  border: 1.5px dashed var(--border);
  border-radius: 12px;
  background: var(--bg-alt);
  color: var(--text-muted);
  font-size: 0.85rem;
  text-align: center;
  padding: 1.5rem;
}
.paper-placeholder i { font-size: 1.4rem; opacity: 0.6; }
.paper-placeholder code {
  font-size: 0.78rem;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: 0.1rem 0.4rem;
}

/* === Interactive point-cloud viewer === */
.pc-viewer {
  position: relative;
  border-radius: 12px;
  overflow: hidden;
  border: 1px solid var(--border);
  background: #0b1220;
  box-shadow: 0 10px 30px rgba(15, 23, 42, 0.1);
}
.pc-canvas-host {
  width: 100%;
  aspect-ratio: 16 / 9;
  display: block;
  cursor: grab;
  touch-action: none;
}
.pc-canvas-host:active { cursor: grabbing; }

.pc-toolbar {
  position: absolute;
  top: 0.75rem;
  left: 0.75rem;
  right: 0.75rem;
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  justify-content: space-between;
  align-items: flex-start;
}
.pc-tabs { display: flex; flex-wrap: wrap; gap: 0.35rem; }
.pc-tab {
  padding: 0.35rem 0.85rem;
  font-size: 0.78rem;
  font-weight: 600;
  border-radius: 100px;
  border: 1px solid rgba(255, 255, 255, 0.22);
  background: rgba(15, 23, 42, 0.55);
  color: #e2e8f0;
  cursor: pointer;
  backdrop-filter: blur(6px);
  transition: background 0.15s, border-color 0.15s;
}
.pc-tab:hover { border-color: rgba(255, 255, 255, 0.5); }
.pc-tab.active { background: var(--accent); border-color: var(--accent); color: #fff; }

.pc-controls {
  display: flex;
  align-items: center;
  gap: 0.7rem;
  background: rgba(15, 23, 42, 0.55);
  border-radius: 100px;
  padding: 0.35rem 0.9rem;
  backdrop-filter: blur(6px);
}
.pc-controls label {
  font-size: 0.72rem;
  color: #cbd5e1;
  display: flex;
  align-items: center;
  gap: 0.35rem;
  white-space: nowrap;
}
.pc-controls input[type="range"] { width: 70px; accent-color: var(--accent); }
.pc-icon-btn {
  background: none;
  border: none;
  color: #e2e8f0;
  cursor: pointer;
  font-size: 0.85rem;
  padding: 0.1rem 0.2rem;
  line-height: 1;
}
.pc-icon-btn:hover { color: #fff; }
.pc-icon-btn.active { color: var(--accent); }

.pc-hint {
  position: absolute;
  bottom: 0.65rem;
  left: 50%;
  transform: translateX(-50%);
  font-size: 0.7rem;
  color: rgba(255, 255, 255, 0.5);
  pointer-events: none;
  white-space: nowrap;
}
.pc-status {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-direction: column;
  gap: 0.6rem;
  color: #94a3b8;
  font-size: 0.85rem;
  background: #0b1220;
  transition: opacity 0.2s;
}
.pc-status.hidden { opacity: 0; pointer-events: none; }
.pc-spinner {
  width: 18px;
  height: 18px;
  border: 2px solid rgba(255, 255, 255, 0.2);
  border-top-color: #fff;
  border-radius: 50%;
  animation: pc-spin 0.7s linear infinite;
}
@keyframes pc-spin { to { transform: rotate(360deg); } }
.pc-status.error { color: #fca5a5; }

.pc-legend {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 1.5rem;
  margin-top: 0.9rem;
}
.pc-legend-item {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--text);
}
.pc-legend-swatch {
  width: 0.85rem;
  height: 0.85rem;
  border-radius: 50%;
  border: 1px solid rgba(15, 23, 42, 0.15);
  flex: 0 0 auto;
}

/* === BibTeX === */
.paper-bibtex {
  position: relative;
  background: var(--bg-alt);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.1rem 1.25rem;
}
.paper-bibtex pre {
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-size: 0.78rem;
  line-height: 1.55;
  white-space: pre;
  overflow-x: auto;
  color: var(--text);
}
.paper-copy-btn {
  position: absolute;
  top: 0.6rem;
  right: 0.6rem;
  font-size: 0.75rem;
  font-weight: 600;
  padding: 0.3rem 0.65rem;
  border-radius: 6px;
  border: 1px solid var(--border);
  background: var(--bg);
  color: var(--text-muted);
  cursor: pointer;
  transition: color 0.15s, border-color 0.15s;
}
.paper-copy-btn:hover { color: var(--accent); border-color: var(--accent); }
.paper-copy-btn.copied { color: #065f46; border-color: #6ee7b7; background: #d1fae5; }

/* === Responsive === */
@media (max-width: 640px) {
  .paper-main { padding: 2rem 1.25rem 4rem; }
  .pc-toolbar { position: static; padding: 0.6rem; background: #0b1220; }
  .pc-canvas-host { aspect-ratio: 4 / 3; }
  .pc-hint { display: none; }
}