.osprog-section{
  --osprog-primary:#1e5eff;
  padding: 28px 0;
}
.osprog-head{ text-align:center; margin-bottom: 14px; }
.osprog-title{ margin:0; font-size: clamp(26px, 3vw, 38px); letter-spacing: -0.02em; }
.osprog-subtitle{ margin:8px 0 0; color: rgba(0,0,0,0.66); font-size: 16px; }

.osprog-cover-wrap{ display:flex; justify-content:center; margin: 16px 0 8px; }
.osprog-cover-btn{
  position:relative; border:0; background:transparent; padding:0; cursor:pointer;
  width:min(420px, 86vw); aspect-ratio: 3/4;
  transform: translateZ(0);
}
.osprog-cover-shadow{
  position:absolute; inset: 10px 14px -10px 14px;
  border-radius: 18px;
  filter: blur(14px);
  background: rgba(0,0,0,0.22);
  z-index:0;
}
.osprog-cover{
  position:relative; z-index:1;
  width:100%; height:100%;
  border-radius: 18px;
  object-fit: cover;
  box-shadow: 0 20px 45px rgba(0,0,0,0.18);
  transition: transform .18s ease, filter .18s ease;
}
.osprog-cover-btn:hover .osprog-cover{ transform: scale(1.015); filter: saturate(1.02); }
.osprog-cover-corner{
  position:absolute; z-index:2;
  top: 10px; right: 12px;
  width: 58px; height: 58px;
  border-top-right-radius: 18px;
  background: linear-gradient(135deg, rgba(255,255,255,0.55), rgba(255,255,255,0.0));
  clip-path: polygon(0 0, 100% 0, 100% 100%);
  opacity: 0.9;
  transform-origin: top right;
}
.osprog-cover-hint{
  position:absolute; z-index:3;
  left: 12px; bottom: 12px;
  padding: 10px 12px;
  border-radius: 999px;
  background: rgba(0,0,0,0.55);
  color: #fff;
  font-weight: 700;
  font-size: 13px;
  letter-spacing: .02em;
}

.osprog-actions-front{ display:flex; justify-content:center; gap:12px; flex-wrap:wrap; margin-top: 12px; }
.osprog-btn{
  appearance:none; border:1px solid rgba(0,0,0,0.12);
  padding: 12px 16px; border-radius: 999px;
  font-weight: 800; cursor:pointer; text-decoration:none;
  transition: transform .12s ease, box-shadow .12s ease, background .12s ease, border-color .12s ease;
  display:inline-flex; align-items:center; gap:8px;
}
.osprog-btn:active{ transform: scale(0.98); }
.osprog-btn-primary{
  background: var(--osprog-primary);
  border-color: transparent;
  color: #fff;
  box-shadow: 0 14px 30px rgba(30,94,255,0.22);
}
.osprog-btn-primary:hover{ box-shadow: 0 18px 40px rgba(30,94,255,0.28); }
.osprog-btn-ghost{ background: rgba(255,255,255,0.72); }
.osprog-note{ display:block; color: rgba(0,0,0,0.6); font-weight: 600; padding: 10px 0; }

.osprog-modal{ position:fixed; inset:0; display:none; z-index: 999999; }
.osprog-modal.is-open{ display:block; }
.osprog-modal-backdrop{ position:absolute; inset:0; background: rgba(0,0,0,0.65); backdrop-filter: blur(6px); }
.osprog-modal-panel{
  position:absolute; inset: 3.5vh 3.5vw;
  background: rgba(255,255,255,0.92);
  border-radius: 18px;
  box-shadow: 0 30px 90px rgba(0,0,0,0.35);
  overflow:hidden;
  display:flex; flex-direction:column;
}
@media (max-width: 720px){
  .osprog-modal-panel{ inset: 0; border-radius: 0; }
}
.osprog-close{
  position:absolute; top: 12px; right: 12px;
  width: 42px; height: 42px;
  border-radius: 999px;
  border: 0;
  background: rgba(0,0,0,0.10);
  font-size: 18px; font-weight: 900;
  cursor:pointer;
  z-index: 4;
}
.osprog-close:hover{ background: rgba(0,0,0,0.16); }

.osprog-viewer{ padding: 18px 18px 8px; flex:1; display:flex; flex-direction:column; gap:10px; }
.osprog-toolbar{ display:flex; align-items:center; justify-content:center; gap:12px; }
.osprog-nav{
  width: 44px; height: 44px; border-radius: 999px;
  border:1px solid rgba(0,0,0,0.12);
  background: rgba(255,255,255,0.85);
  cursor:pointer;
  font-size: 24px; font-weight: 900;
}
.osprog-counter{ font-weight: 900; letter-spacing: .03em; opacity: 0.75; }

.osprog-book{
  position:relative;
  flex:1;
  display:flex; align-items:center; justify-content:center;
  user-select:none;
}
.osprog-loading{ opacity:0.7; font-weight:800; }

.osprog-spread{
  position:relative;
  width: min(1100px, 96%);
  height: min(74vh, 720px);
  display:flex;
  gap: 0;
  border-radius: 14px;
  box-shadow: 0 24px 70px rgba(0,0,0,0.18);
  overflow:hidden;
  background: #fff;
}
@media (max-width: 900px){
  .osprog-spread{ width: min(520px, 96%); }
}
.osprog-page{
  position:relative;
  flex:1;
  background:#fff;
  overflow:hidden;
}
.osprog-page img{
  width:100%; height:100%;
  object-fit: contain;
  background:#fff;
}
.osprog-page.left{ border-right: 1px solid rgba(0,0,0,0.07); }
@media (max-width: 900px){
  .osprog-page.left{ display:none; }
  .osprog-page.right{ flex:1; }
}
.osprog-flip{
  position:absolute; top:0; right:0;
  width:50%; height:100%;
  transform-style: preserve-3d;
  transform-origin: left center;
  pointer-events:none;
  display:none;
}
.osprog-flip.is-active{ display:block; }
.osprog-flip .front, .osprog-flip .back{
  position:absolute; inset:0;
  backface-visibility: hidden;
  background:#fff;
}
.osprog-flip .front img, .osprog-flip .back img{ width:100%; height:100%; object-fit: contain; }
.osprog-flip .back{ transform: rotateY(180deg); }
.osprog-flip.is-turning{
  animation: osprogTurn .48s ease-in-out forwards;
}
@keyframes osprogTurn{
  0% { transform: rotateY(0deg); box-shadow: -10px 0 25px rgba(0,0,0,0.15); }
  100%{ transform: rotateY(-180deg); box-shadow: -18px 0 40px rgba(0,0,0,0.12); }
}

.osprog-footer{
  padding: 10px 16px 16px;
  text-align:center;
  border-top: 1px solid rgba(0,0,0,0.08);
  background: rgba(255,255,255,0.80);
}
.osprog-footer-link{
  font-weight: 900;
  color: var(--osprog-primary);
  text-decoration:none;
}
.osprog-footer-link:hover{ text-decoration:underline; }

/* micro hint animation */
@keyframes osprogCornerWiggle{
  0% { transform: rotate(0deg) scale(1); }
  40%{ transform: rotate(-10deg) scale(1.02); }
  70%{ transform: rotate(0deg) scale(1); }
  100%{ transform: rotate(0deg) scale(1); }
}
.osprog-hint-anim .osprog-cover-corner{
  animation: osprogCornerWiggle 1.2s ease-in-out 1;
}