.lesson-intro-card {
  position: relative;
  display: grid;
  grid-template-columns: minmax(320px, 1.35fr) minmax(280px, .65fr);
  gap: 0;
  margin: 1.5rem 0;
  overflow: hidden;
  border: 3px solid rgba(33, 150, 243, .18);
  border-radius: 28px;
  background: linear-gradient(135deg, #e8f9ff, #fff3c9);
  box-shadow: 0 10px 30px rgba(18, 73, 120, .13);
}

.lesson-intro-card__poster {
  position: relative;
  min-height: 310px;
  overflow: hidden;
  background: #dff7ff;
}

.lesson-intro-card__poster img {
  width: 100%;
  height: 100%;
  min-height: 310px;
  display: block;
  object-fit: cover;
}

.lesson-intro-card__poster::after {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(90deg, transparent 68%, rgba(255, 243, 201, .9));
  pointer-events: none;
}

.lesson-intro-card__body {
  position: relative;
  z-index: 2;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: flex-start;
  padding: 2rem 1.8rem 2rem 1rem;
}

.lesson-intro-card__eyebrow {
  margin: 0 0 .45rem;
  color: #1976d2;
  font-weight: 900;
  letter-spacing: .04em;
}

.lesson-intro-card h2 {
  margin: 0;
  color: #143f78;
  font-size: clamp(1.55rem, 3vw, 2.25rem);
  line-height: 1.2;
}

.lesson-intro-card__meta {
  margin: .65rem 0 1.25rem;
  color: #546e7a;
  font-size: .95rem;
  font-weight: 700;
}

.lesson-intro-card__play {
  min-height: 52px;
  padding: .78rem 1.35rem;
  border: 0;
  border-radius: 999px;
  color: #fff;
  background: linear-gradient(135deg, #1976d2, #2196f3);
  box-shadow: 0 7px 0 #0d5ca8;
  font: inherit;
  font-weight: 900;
  cursor: pointer;
  transition: transform .18s ease, box-shadow .18s ease;
}

.lesson-intro-card__play:hover { transform: translateY(-2px); box-shadow: 0 9px 0 #0d5ca8; }
.lesson-intro-card__play:active { transform: translateY(4px); box-shadow: 0 3px 0 #0d5ca8; }
.lesson-intro-card__play:focus-visible { outline: 4px solid #ffca28; outline-offset: 4px; }

body.lesson-intro-open { overflow: hidden; }

.lesson-intro-modal[hidden],
.lesson-intro-ended[hidden] { display: none !important; }

.lesson-intro-modal {
  position: fixed;
  inset: 0;
  z-index: 10000;
  display: grid;
  grid-template-rows: auto minmax(0, 1fr) auto;
  padding: max(12px, 2vh) max(12px, 2vw);
  color: #fff;
  background: rgba(5, 17, 34, .97);
}

.lesson-intro-modal__header,
.lesson-intro-modal__footer {
  width: min(1500px, 100%);
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}

.lesson-intro-modal__header { padding-bottom: 12px; }
.lesson-intro-modal__header strong { font-size: clamp(1.05rem, 2.2vw, 1.6rem); }

.lesson-intro-modal__stage {
  position: relative;
  width: min(1500px, 100%);
  min-height: 0;
  margin: auto;
  display: grid;
  place-items: center;
}

.lesson-intro-modal video {
  width: auto;
  height: auto;
  max-width: 100%;
  max-height: calc(100vh - 150px);
  aspect-ratio: 16 / 9;
  display: block;
  border-radius: 18px;
  background: #000;
  box-shadow: 0 18px 55px rgba(0,0,0,.45);
}

.lesson-intro-modal button {
  min-height: 44px;
  padding: .6rem 1rem;
  border: 2px solid rgba(255,255,255,.36);
  border-radius: 999px;
  color: #fff;
  background: rgba(255,255,255,.12);
  font: inherit;
  font-weight: 900;
  cursor: pointer;
}

.lesson-intro-modal button:hover { background: rgba(255,255,255,.22); }
.lesson-intro-modal button:focus-visible { outline: 4px solid #ffca28; outline-offset: 3px; }
.lesson-intro-modal__footer { padding-top: 12px; justify-content: flex-end; }
.lesson-intro-status { margin-right: auto; color: #dbeeff; font-size: .9rem; }

.lesson-intro-ended {
  position: absolute;
  inset: 0;
  display: grid;
  place-items: center;
  border-radius: 18px;
  background: rgba(8, 31, 62, .86);
  text-align: center;
}

.lesson-intro-ended__panel {
  width: min(560px, 90%);
  padding: 2rem;
  border-radius: 28px;
  background: #fff;
  color: #143f78;
  box-shadow: 0 18px 50px rgba(0,0,0,.3);
}

.lesson-intro-ended__panel h2 { margin: 0 0 .6rem; font-size: clamp(1.5rem, 4vw, 2.35rem); }
.lesson-intro-ended__panel p { margin: 0 0 1.3rem; color: #455a64; }
.lesson-intro-ended__actions { display: flex; justify-content: center; flex-wrap: wrap; gap: .75rem; }
.lesson-intro-ended__actions button { color: #143f78; border-color: #bbdefb; background: #e3f2fd; }
.lesson-intro-ended__actions .lesson-intro-start { color: #fff; border-color: #1976d2; background: #1976d2; }

@media (max-width: 760px) {
  .lesson-intro-card { grid-template-columns: 1fr; }
  .lesson-intro-card__poster, .lesson-intro-card__poster img { min-height: 210px; }
  .lesson-intro-card__poster::after { background: linear-gradient(0deg, rgba(255, 243, 201, .92), transparent 45%); }
  .lesson-intro-card__body { padding: 1.25rem; }
  .lesson-intro-modal { padding: 10px; }
  .lesson-intro-modal__footer { flex-wrap: wrap; }
  .lesson-intro-status { width: 100%; order: 2; }
}

@media (prefers-reduced-motion: reduce) {
  .lesson-intro-card__play { transition: none; }
  .lesson-intro-card__play:hover { transform: none; }
}