frontend/src/pages/presentation.css

.presentation {
  position: relative;
  background: #05080d;
}

.presentation__track {
  position: relative;
  height: 880vh;
}

.stage {
  position: sticky;
  top: 0;
  height: 100vh;
  height: 100svh;
  overflow: hidden;
  background: #05080d;
}

.scene {
  position: absolute;
  inset: 0;
  background-size: cover;
  background-position: center;
  display: flex;
  align-items: flex-end;
  justify-content: center;
}

.scene__veil {
  position: absolute;
  inset: 0;
  background: linear-gradient(
    180deg,
    rgba(5, 8, 13, 0.55) 0%,
    rgba(5, 8, 13, 0.12) 38%,
    rgba(5, 8, 13, 0.86) 100%
  );
}

.scene__text {
  position: relative;
  text-align: center;
  padding: 0 24px 12vh;
  max-width: 780px;
}

.scene__kicker {
  text-transform: uppercase;
  letter-spacing: 0.4em;
  font-size: 11px;
  color: #8fa6bd;
  margin-bottom: 14px;
}

.scene__title {
  font-size: clamp(30px, 5vw, 58px);
  font-weight: 500;
  letter-spacing: 0.04em;
  margin: 0;
  color: #eaf2fb;
  text-shadow: 0 2px 30px rgba(0, 0, 0, 0.6);
}

.scene__sub {
  margin: 14px auto 0;
  color: #c9d6e5;
  max-width: 540px;
  font-size: 14px;
  text-shadow: 0 1px 16px rgba(0, 0, 0, 0.7);
}

.scene__shade {
  position: absolute;
  left: 0;
  right: 0;
  top: -8%;
  height: 108%;
  background:
    linear-gradient(
      180deg,
      rgba(8, 10, 14, 0.98) 0%,
      rgba(18, 23, 30, 0.97) 70%,
      rgba(28, 34, 44, 0.92) 88%,
      rgba(44, 51, 61, 0.5) 96%,
      rgba(44, 51, 61, 0) 100%
    );
  filter: blur(1.5px);
  pointer-events: none;
}

.scene__shade::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: -6%;
  height: 14%;
  background: radial-gradient(
    ellipse at 50% 0%,
    rgba(28, 34, 44, 0.75) 0%,
    rgba(28, 34, 44, 0.3) 40%,
    rgba(28, 34, 44, 0) 75%
  );
  filter: blur(6px);
  pointer-events: none;
}

.explain {
  position: absolute;
  inset: 0;
  display: grid;
  place-items: center;
}

.explain__header {
  position: absolute;
  top: 12vh;
  left: 0;
  right: 0;
  text-align: center;
  text-transform: uppercase;
  letter-spacing: 0.4em;
  font-size: 12px;
  color: var(--info);
}

.explain__panel {
  position: absolute;
  width: min(560px, 86vw);
  border: 1px solid var(--panel-edge);
  background: rgba(8, 13, 20, 0.82);
  backdrop-filter: blur(2px);
  padding: 28px 30px;
  text-align: left;
}

.explain__panel h3 {
  margin: 0 0 8px;
  font-size: 18px;
  letter-spacing: 0.06em;
  color: var(--info);
}

.explain__panel p {
  margin: 0;
  color: var(--text);
  font-size: 14px;
}

.ack {
  position: absolute;
  inset: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 10px;
  text-align: center;
}

.ack__title {
  font-size: clamp(26px, 4vw, 44px);
  letter-spacing: 0.12em;
  color: #eaf2fb;
}

.presentation__skip {
  position: fixed;
  top: 18px;
  right: 18px;
  z-index: 20;
}

.presentation__progress {
  position: fixed;
  left: 0;
  top: 0;
  height: 2px;
  background: var(--info);
  transform-origin: 0 50%;
  z-index: 20;
}

@media (max-width: 900px) {
  .presentation__track {
    height: 700vh;
    height: 700svh;
  }

  .scene {
    align-items: center;
  }

  .scene__text {
    padding: 0 18px 14vh;
    max-width: 100%;
  }

  .scene__kicker {
    letter-spacing: 0.28em;
    font-size: 10px;
  }

  .scene__title {
    letter-spacing: 0.02em;
  }

  .scene__sub {
    font-size: 13px;
    max-width: 92vw;
    padding-bottom: 8px;
  }

  .explain__header {
    top: 8vh;
    letter-spacing: 0.28em;
    font-size: 11px;
    padding: 0 12px;
  }

  .explain__panel {
    width: min(92vw, 520px);
    padding: 18px 18px;
  }

  .explain__panel h3 {
    font-size: 16px;
  }

  .explain__panel p {
    font-size: 13px;
  }

  .presentation__skip {
    top: 12px;
    right: 12px;
    background: rgba(5, 8, 13, 0.6);
    padding: 6px 8px;
    border-radius: 2px;
  }
}