/* James study library: a quiet eBook shelf with a brief book-opening handoff. */
.study-material-catalog {
  --study-accent: #087b62;
  --study-accent-dark: #075642;
  --study-glow-rgb: 33, 186, 151;
  position: relative;
  isolation: isolate;
  min-width: 0;
  margin: 18px 0 28px;
  padding: clamp(20px, 3.8vw, 34px);
  overflow: hidden;
  border: 1px solid #dce9df;
  border-radius: 28px;
  background: linear-gradient(145deg, #fcfffc 0%, #f3faf6 57%, #eaf5ee 100%);
  box-shadow: 0 18px 48px rgba(13, 61, 46, .07);
  color: #18352b;
}

.study-material-catalog[data-category="biology"] {
  --study-accent: #588a20;
  --study-accent-dark: #3f6717;
  --study-glow-rgb: 166, 216, 77;
  border-color: #e3ebd9;
  background: linear-gradient(145deg, #fffffb 0%, #f8fbef 55%, #eef6e4 100%);
}

.study-material-catalog[data-category="english"] {
  --study-accent: #8b456b;
  --study-accent-dark: #63314d;
  --study-glow-rgb: 207, 128, 174;
  border-color: #eedfe9;
  background: linear-gradient(145deg, #fffdfd 0%, #fbf4f8 55%, #f5eaf2 100%);
}

.study-material-catalog[data-category="earth-science"] {
  --study-accent: #365d92;
  --study-accent-dark: #23436e;
  --study-glow-rgb: 116, 167, 223;
  border-color: #dce7f2;
  background: linear-gradient(145deg, #fcfeff 0%, #f1f7fc 55%, #e9f2fb 100%);
}

.study-material-catalog::before {
  position: absolute;
  z-index: -1;
  top: -170px;
  right: -130px;
  width: min(65vw, 580px);
  aspect-ratio: 1;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(var(--study-glow-rgb), .12), transparent 68%);
  content: "";
  pointer-events: none;
}

.study-material-heading {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 20px;
  margin-bottom: 22px;
}

.study-material-heading > div {
  min-width: 0;
}

.study-material-heading .eyebrow {
  display: inline-flex;
  margin-bottom: 8px;
  color: var(--study-accent-dark);
  font-size: 12px;
  font-weight: 800;
  letter-spacing: .025em;
}

.study-material-heading h2 {
  margin: 0 0 7px;
  color: #16382d;
  font-size: clamp(22px, 2.9vw, 29px);
  font-weight: 800;
  line-height: 1.3;
  letter-spacing: -.035em;
}

.study-material-heading p {
  max-width: 640px;
  margin: 0;
  color: #61776b;
  font-size: 14px;
  line-height: 1.65;
}

.study-material-heading > button {
  flex: 0 0 auto;
  min-height: 40px;
  border-radius: 12px;
}

.study-material-tabs {
  display: inline-flex;
  flex-wrap: wrap;
  gap: 5px;
  max-width: 100%;
  margin: 0 0 24px;
  padding: 5px;
  border: 1px solid #dce8df;
  border-radius: 15px;
  background: rgba(255, 255, 255, .86);
}

.study-material-tabs button {
  min-width: 88px;
  min-height: 38px;
  padding: 6px 16px;
  border: 0;
  border-radius: 11px;
  background: transparent;
  color: #65776d;
  font: inherit;
  font-size: 14px;
  font-weight: 750;
  cursor: pointer;
  transition: background-color 180ms ease, color 180ms ease, box-shadow 180ms ease;
}

.study-material-tabs button:hover {
  color: var(--study-accent-dark);
  background: rgba(var(--study-glow-rgb), .09);
}

.study-material-tabs button.active,
.study-material-tabs button[aria-selected="true"] {
  background: var(--study-accent);
  color: #fff;
  box-shadow: 0 3px 9px rgba(11, 75, 53, .15);
}

.study-material-grid {
  position: relative;
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  align-items: stretch;
  gap: clamp(14px, 2.3vw, 25px);
  min-width: 0;
  padding: 4px 4px 20px;
}

/* One subtle shelf under the books, never a competing card border. */
.study-material-grid::after {
  position: absolute;
  z-index: 0;
  right: 0;
  bottom: 1px;
  left: 0;
  height: 15px;
  border-radius: 6px 6px 12px 12px;
  background: linear-gradient(#d6e3d8 0 3px, #bed2c2 3px 8px, #e4eee5 100%);
  box-shadow: 0 8px 17px rgba(37, 83, 49, .13);
  content: "";
  pointer-events: none;
}

.study-material-card {
  --study-book-width: min(184px, calc(100% - 44px));
  position: relative;
  z-index: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  min-width: 0;
  padding: 22px 18px 20px;
  border: 1px solid rgba(38, 98, 65, .13);
  border-radius: 21px;
  background: rgba(255, 255, 255, .86);
  box-shadow: 0 10px 26px rgba(20, 65, 44, .07);
  perspective: 1100px;
  transform: translateZ(0);
  transition: transform 260ms ease, box-shadow 260ms ease, border-color 260ms ease;
}

.study-material-card[data-subject="biology"] {
  --study-glow-rgb: 166, 216, 77;
}

.study-material-card[data-subject="english"] {
  --study-glow-rgb: 207, 128, 174;
}

.study-material-card[data-subject="earth-science"] {
  --study-glow-rgb: 116, 167, 223;
}

.study-material-card:hover,
.study-material-card:focus-within {
  z-index: 2;
  transform: translateY(-5px);
  border-color: rgba(var(--study-glow-rgb), .5);
  box-shadow: 0 17px 32px rgba(20, 65, 44, .12);
}

/* The page block lives behind the real PDF cover image. */
.study-material-card::before {
  position: absolute;
  z-index: 0;
  top: 22px;
  left: 50%;
  width: var(--study-book-width);
  aspect-ratio: var(--study-cover-ratio, 595 / 842);
  border: 1px solid #cfded4;
  border-radius: 3px 9px 9px 3px;
  background: repeating-linear-gradient(90deg, #fff 0 3px, #edf2ec 3px 4px, #fff 4px 8px);
  box-shadow: 5px 8px 12px rgba(13, 50, 31, .2);
  content: "";
  opacity: 0;
  pointer-events: none;
  transform: translateX(-50%) translateZ(-12px);
}

.study-material-card::after {
  position: absolute;
  z-index: -1;
  inset: -16px;
  border-radius: 30px;
  background: radial-gradient(circle at 50% 39%, rgba(var(--study-glow-rgb), .48), transparent 66%);
  content: "";
  opacity: 0;
  pointer-events: none;
  filter: blur(12px);
}

.study-material-cover {
  position: relative;
  z-index: 1;
  width: var(--study-book-width);
  aspect-ratio: var(--study-cover-ratio, 595 / 842);
  margin: 0 0 20px;
  overflow: hidden;
  border: 1px solid rgba(8, 58, 39, .2);
  border-radius: 4px 10px 10px 4px;
  background: linear-gradient(150deg, #f8fbf5, #dcebe0);
  box-shadow: 3px 3px 0 #dbe4db, 7px 12px 17px rgba(16, 53, 35, .21);
  transform: rotateY(-8deg) rotateZ(-.8deg);
  transform-origin: 8% 50%;
  transform-style: preserve-3d;
  backface-visibility: hidden;
  transition: transform 380ms cubic-bezier(.2, .75, .2, 1), box-shadow 380ms ease;
}

.study-material-cover::before {
  position: absolute;
  z-index: 2;
  inset: 0 auto 0 0;
  width: 10px;
  background: linear-gradient(90deg, rgba(0, 0, 0, .33), rgba(255, 255, 255, .18) 62%, transparent);
  content: "";
  pointer-events: none;
}

.study-material-cover img {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: contain;
  user-select: none;
  -webkit-user-drag: none;
}

.study-material-card:hover .study-material-cover,
.study-material-card:focus-within .study-material-cover {
  box-shadow: 4px 3px 0 #e0e7dc, 12px 20px 24px rgba(16, 53, 35, .23);
  transform: rotateY(-15deg) rotateZ(-1.4deg) translateY(-3px);
}

.study-material-card-copy {
  position: relative;
  z-index: 1;
  width: 100%;
  min-width: 0;
  text-align: center;
}

.study-material-card-copy > span {
  display: block;
  margin-bottom: 7px;
  color: var(--study-accent-dark);
  font-size: 12px;
  font-weight: 800;
}

.study-material-card-copy h3 {
  margin: 0;
  color: #1c3429;
  font-size: clamp(16px, 1.9vw, 19px);
  font-weight: 800;
  line-height: 1.35;
  overflow-wrap: anywhere;
}

.study-material-card-copy p {
  margin: 6px 0 0;
  color: #6a7b70;
  font-size: 13px;
  line-height: 1.5;
}

.study-material-actions {
  position: relative;
  z-index: 1;
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 7px;
  width: 100%;
  margin-top: auto;
  padding-top: 17px;
}

.study-material-actions button {
  min-height: 40px;
  border-radius: 11px;
  font-size: 13px;
  font-weight: 750;
}

.study-material-actions button.primary {
  background: var(--study-accent);
  border-color: var(--study-accent);
  color: #fff;
}

.study-material-actions button.primary:hover {
  background: var(--study-accent-dark);
  border-color: var(--study-accent-dark);
}

.study-material-catalog :where(button, a):focus-visible {
  outline: 3px solid rgba(var(--study-glow-rgb), .7);
  outline-offset: 3px;
}

.study-material-empty {
  margin: 0;
  padding: 32px 18px;
  border: 1px dashed #cbded1;
  border-radius: 16px;
  background: rgba(255, 255, 255, .75);
  color: #61776b;
  text-align: center;
  line-height: 1.6;
}

/* JS adds is-opening briefly before navigating to the page reader. */
.study-material-card.is-opening {
  z-index: 3;
  transform: translateY(-8px) scale(1.015);
  border-color: rgba(var(--study-glow-rgb), .55);
  box-shadow: 0 24px 46px rgba(var(--study-glow-rgb), .24);
  pointer-events: none;
}

.study-material-card.is-opening::before {
  opacity: 1;
}

.study-material-card.is-opening::after {
  animation: james-study-card-glow 650ms ease-out both;
}

.study-material-card.is-opening .study-material-cover {
  animation: james-study-book-open 650ms cubic-bezier(.18, .72, .26, 1) both;
}

@keyframes james-study-book-open {
  0% { transform: rotateY(-8deg) rotateZ(-.8deg) translateZ(0); }
  42% { transform: rotateY(-52deg) rotateZ(-2deg) translateZ(16px); }
  100% { transform: rotateY(-154deg) rotateZ(-2deg) translateZ(24px); }
}

@keyframes james-study-card-glow {
  0% { opacity: 0; transform: scale(.88); }
  55% { opacity: .88; transform: scale(1.04); }
  100% { opacity: .22; transform: scale(1.22); }
}

body[data-study-world="chemistry"] {
  --study-world-rgb: 43, 216, 219;
  --study-world-deep: #063e4d;
}

body[data-study-world="biology"] {
  --study-world-rgb: 169, 227, 80;
  --study-world-deep: #114d35;
}

body[data-study-world="english"] {
  --study-world-rgb: 224, 157, 196;
  --study-world-deep: #482b50;
}

body[data-study-world="earth-science"] {
  --study-world-rgb: 116, 187, 242;
  --study-world-deep: #132d58;
}

/* Full-screen light covers the route handoff without blocking taps afterward. */
body.study-world-entering::after {
  position: fixed;
  z-index: 2147482900;
  inset: 0;
  background:
    radial-gradient(circle at var(--study-origin-x, 50%) var(--study-origin-y, 50%),
      rgba(var(--study-world-rgb, 43, 216, 219), .83),
      rgba(var(--study-world-rgb, 43, 216, 219), .33) 32%,
      var(--study-world-deep, #063e4d) 100%);
  content: "";
  pointer-events: none;
  animation: james-study-world-enter 950ms ease-in-out both;
}

/* A few static molecular lights imply a chemistry world without image requests
   or a continuously running particle animation. */
body.study-world-entering[data-study-world="chemistry"]::after {
  background:
    radial-gradient(circle 9px at calc(var(--study-origin-x, 50%) - 108px) calc(var(--study-origin-y, 50%) - 44px),
      #fff 0 25%, #94fff4 55%, transparent 100%),
    radial-gradient(circle 13px at calc(var(--study-origin-x, 50%) + 112px) calc(var(--study-origin-y, 50%) + 37px),
      #fff 0 18%, #7df1fb 55%, transparent 100%),
    radial-gradient(circle 6px at calc(var(--study-origin-x, 50%) + 25px) calc(var(--study-origin-y, 50%) - 95px),
      #f2fffe 0 30%, #a5f7d9 65%, transparent 100%),
    radial-gradient(ellipse 175px 58px at var(--study-origin-x, 50%) var(--study-origin-y, 50%),
      transparent 92%, rgba(192, 255, 250, .65) 96%, transparent 100%),
    radial-gradient(circle at var(--study-origin-x, 50%) var(--study-origin-y, 50%),
      rgba(43, 216, 219, .84), rgba(43, 216, 219, .34) 32%, #063e4d 100%);
}

/* Warm page-light for English, and a night-sky horizon for earth science. */
body.study-world-entering[data-study-world="english"]::after {
  background:
    radial-gradient(ellipse 180px 70px at calc(var(--study-origin-x, 50%) - 82px) calc(var(--study-origin-y, 50%) - 58px),
      rgba(255, 244, 252, .8), transparent 72%),
    radial-gradient(ellipse 160px 65px at calc(var(--study-origin-x, 50%) + 96px) calc(var(--study-origin-y, 50%) + 44px),
      rgba(251, 202, 223, .65), transparent 76%),
    radial-gradient(circle at var(--study-origin-x, 50%) var(--study-origin-y, 50%),
      rgba(224, 157, 196, .85), rgba(175, 99, 156, .37) 35%, #482b50 100%);
}

body.study-world-entering[data-study-world="earth-science"]::after {
  background:
    radial-gradient(circle 4px at 24% 24%, rgba(239, 250, 255, .95) 40%, transparent 100%),
    radial-gradient(circle 3px at 79% 32%, rgba(239, 250, 255, .92) 40%, transparent 100%),
    radial-gradient(circle 3px at 63% 15%, rgba(239, 250, 255, .9) 40%, transparent 100%),
    radial-gradient(ellipse 260px 84px at var(--study-origin-x, 50%) calc(var(--study-origin-y, 50%) + 68px),
      transparent 72%, rgba(177, 222, 255, .72) 75%, transparent 82%),
    radial-gradient(circle at var(--study-origin-x, 50%) var(--study-origin-y, 50%),
      rgba(116, 187, 242, .86), rgba(64, 122, 194, .4) 35%, #132d58 100%);
}

@keyframes james-study-world-enter {
  0% {
    opacity: 0;
    clip-path: circle(0 at var(--study-origin-x, 50%) var(--study-origin-y, 50%));
  }
  43% { opacity: 1; }
  56% {
    opacity: 1;
    clip-path: circle(150vmax at var(--study-origin-x, 50%) var(--study-origin-y, 50%));
  }
  100% {
    opacity: 0;
    clip-path: circle(150vmax at var(--study-origin-x, 50%) var(--study-origin-y, 50%));
  }
}

@media (max-width: 930px) {
  .study-material-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (max-width: 620px) {
  .study-material-catalog {
    margin: 12px 0 22px;
    padding: 19px 15px 22px;
    border-radius: 20px;
  }

  .study-material-heading {
    flex-direction: column;
    gap: 12px;
  }

  .study-material-heading > button {
    align-self: flex-start;
  }

  .study-material-tabs {
    width: 100%;
  }

  .study-material-tabs button {
    flex: 1 1 calc(50% - 5px);
  }

  .study-material-grid {
    grid-template-columns: minmax(0, 1fr);
    gap: 12px;
    padding-inline: 0;
  }

  .study-material-card {
    --study-book-width: min(124px, 30vw);
    display: grid;
    grid-template-columns: var(--study-book-width) minmax(0, 1fr);
    align-items: center;
    column-gap: 16px;
    min-height: 188px;
    padding: 15px;
    border-radius: 17px;
  }

  .study-material-card::before {
    top: 15px;
    left: 15px;
    transform: translateZ(-12px);
  }

  .study-material-cover {
    grid-row: 1 / 3;
    grid-column: 1;
    width: var(--study-book-width);
    margin: 0;
  }

  .study-material-card-copy {
    grid-row: 1;
    grid-column: 2;
    align-self: end;
    text-align: left;
  }

  .study-material-actions {
    grid-row: 2;
    grid-column: 2;
    justify-content: flex-start;
    align-self: start;
    padding-top: 12px;
  }

  .study-material-actions button {
    min-height: 36px;
    padding: 6px 10px;
  }
}

@media (max-width: 380px) {
  .study-material-card {
    --study-book-width: 104px;
    column-gap: 12px;
    padding: 12px;
  }

  .study-material-card::before {
    top: 12px;
    left: 12px;
  }

  .study-material-card-copy h3 {
    font-size: 15px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .study-material-catalog *,
  .study-material-card,
  .study-material-cover {
    scroll-behavior: auto !important;
    transition-duration: 0ms !important;
    animation-duration: 0ms !important;
  }

  .study-material-card:hover,
  .study-material-card:focus-within,
  .study-material-card.is-opening {
    transform: none;
  }

  .study-material-card.is-opening .study-material-cover {
    transform: none;
  }

  body.study-world-entering::after {
    display: none;
  }
}