.m-timeline {
  --container-width: min(87.5rem, 90vw);
  --container-offset: calc((100vw - var(--container-width)) / 2);

  --m-timeline-card-width: clamp(20rem, 27vw, 24rem);
  --m-timeline-gap: clamp(1rem, 2vw, 1.5rem);

  --m-timeline-text: #000000;
  --m-timeline-muted: #777;
  --m-timeline-border: #1B61AC;
  --m-timeline-line: #d8d2c8;
  --m-timeline-card: #fff;
  --m-timeline-accent: #1B61AC;
  --m-timeline-accent-soft: rgba(0, 0, 0, 0.1);
  --m-timeline-shadow: 0 18px 45px rgba(0, 0, 0, 0.08);

  position: relative;
  width: 100vw;
  margin-left: calc(50% - 50vw);
  margin-top: 3rem;
  margin-bottom: 3rem;
  overflow: hidden;
  color: var(--m-timeline-text);
  padding: clamp(1.5rem, 3vw, 2rem) 0;
}

.m-timeline__controls {
  width: var(--container-width);
  margin: 0 auto clamp(0.875rem, 1.5vw, 1.125rem);
  display: flex;
  justify-content: flex-end;
  gap: 0.625rem;
}

.m-timeline__controls button {
  width: clamp(2.5rem, 3vw, 2.75rem);
  height: clamp(2.5rem, 3vw, 2.75rem);
  border: 0;
  border-radius: 50%;
  background: #f2f2f2;
  color: var(--m-timeline-text);
  font-size: clamp(1.625rem, 2vw, 1.875rem);
  line-height: 1;
  cursor: pointer;
  transition:
    background 0.2s ease,
    color 0.2s ease,
    transform 0.2s ease,
    opacity 0.2s ease;
}

.m-timeline__controls button:hover {
  background: var(--m-timeline-accent);
  color: #fff;
}

.m-timeline__controls button:disabled,
.m-timeline__controls button.is-disabled {
  opacity: 0.35;
  cursor: default;
}

.m-timeline__controls button:disabled:hover,
.m-timeline__controls button.is-disabled:hover {
  background: #f2f2f2;
  color: var(--m-timeline-text);
}

.m-timeline__controls button:focus-visible,
.m-timeline__track:focus-visible {
  outline: 3px solid var(--m-timeline-accent);
  outline-offset: 4px;
}

.m-timeline__track {
  position: relative;
  display: flex;
  flex-direction: row;
  flex-wrap: nowrap;
  gap: var(--m-timeline-gap);

  margin: 0;
  padding-left: var(--container-offset);
  padding-right: var(--container-offset);

  padding-top: clamp(4.75rem, 7vw, 6.25rem);
  padding-bottom: 6rem;

  list-style: none;

  overflow-x: auto;
  overflow-y: hidden;

  scroll-snap-type: x mandatory;
  scroll-padding-left: var(--container-offset);
  scroll-padding-right: var(--container-offset);

  -webkit-overflow-scrolling: touch;
  overscroll-behavior-x: contain;

  cursor: grab;
  user-select: none;

  scrollbar-width: none;
  -ms-overflow-style: none;
}

.m-timeline__track::-webkit-scrollbar {
  display: none;
}

.m-timeline__track.is-dragging {
  cursor: grabbing;
  scroll-snap-type: none;
}

.m-timeline__track::before {
  content: "";
  position: absolute;
  top: clamp(2.8rem, 4.6vw, 3.65rem);
  left: var(--container-offset);
  right: var(--container-offset);
  height: 1.65rem;
  background:
    linear-gradient(
      90deg,
      rgba(43, 43, 43, 0.08),
      rgba(43, 43, 43, 0.02)
    );
  border-top: 1px solid rgba(43, 43, 43, 0.08);
  border-bottom: 1px solid rgba(43, 43, 43, 0.055);
  mask-image: linear-gradient(
    90deg,
    transparent,
    black 4%,
    black 96%,
    transparent
  );
  pointer-events: none;
}

.m-timeline__track::after {
  content: "";
  position: absolute;
  top: clamp(2.8rem, 4.6vw, 3.65rem);
  left: var(--container-offset);
  right: var(--container-offset);
  height: 1.65rem;
  background-image: repeating-linear-gradient(
    90deg,
    rgba(43, 43, 43, 0.16) 0,
    rgba(43, 43, 43, 0.16) 1px,
    transparent 1px,
    transparent clamp(1.1rem, 2vw, 1.75rem)
  );
  opacity: 0.28;
  mask-image: linear-gradient(
    90deg,
    transparent,
    black 5%,
    black 95%,
    transparent
  );
  pointer-events: none;
}

.m-timeline__item {
  position: relative;
  flex: 0 0 var(--m-timeline-card-width);
  max-width: var(--m-timeline-card-width);
  scroll-snap-align: start;

  opacity: 0.52;
  transform: translateY(10px);
  cursor: pointer;

  transition:
    opacity 260ms ease,
    transform 260ms ease;
}

.m-timeline__item:focus-visible {
  outline: 3px solid var(--m-timeline-accent);
  outline-offset: 6px;
}

.m-timeline__track.is-dragging .m-timeline__item {
  cursor: grabbing;
}

/*
  Jahreszahl als moderner Typo-Marker:
  nicht riesig, sondern hochwertig, ruhig, präzise.
*/
.m-timeline__item::before {
  content: attr(data-year);
  position: absolute;
  left: 0;
  bottom: calc(100% + 2.05rem);
  z-index: 3;

  display: inline-flex;
  align-items: center;
  justify-content: center;

  min-width: 4.25rem;
  height: 2rem;
  padding: 0 0.85rem;

  color: rgba(43, 43, 43, 0.58);
  background: rgba(255, 255, 255, 0.74);
  border: 1px solid rgba(43, 43, 43, 0.08);
  border-radius: 999px;

  font-size: 0.82rem;
  line-height: 1;
  font-weight: 600;
  letter-spacing: 0.08em;

  box-shadow:
    0 0.35rem 1.25rem rgba(0, 0, 0, 0.035),
    inset 0 1px 0 rgba(255, 255, 255, 0.9);

  transform-origin: left center;
  transform: translateY(0) scale(1);

  transition:
    color 260ms ease,
    background-color 260ms ease,
    border-color 260ms ease,
    box-shadow 260ms ease,
    transform 260ms ease,
    min-width 260ms ease,
    letter-spacing 260ms ease;
}

/*
  Marker statt Punkt:
  eine kleine elegante vertikale Marke im technischen Track.
*/
.m-timeline__item::after {
  content: "";
  position: absolute;
  left: 1.65rem;
  bottom: calc(100% + 0.72rem);
  z-index: 4;

  width: 0.16rem;
  height: 1.25rem;
  border-radius: 999px;
  background: rgba(43, 43, 43, 0.28);

  box-shadow:
    0 0 0 0.35rem rgba(255, 255, 255, 0.68);

  transition:
    background-color 220ms ease,
    height 220ms ease,
    transform 220ms ease,
    box-shadow 220ms ease;
}

.m-timeline__item.is-active {
  opacity: 1;
  transform: translateY(0);
}

.m-timeline__item.is-active::before {
  min-width: 5.5rem;
  color: #fff;
  background: var(--m-timeline-accent);
  border-color: var(--m-timeline-accent);

  letter-spacing: 0.1em;
  transform: translateY(-0.15rem) scale(1.08);

  box-shadow:
    0 0.85rem 2rem rgba(139, 30, 30, 0.16),
    inset 0 1px 0 rgba(255, 255, 255, 0.18);
}

.m-timeline__item.is-active::after {
  height: 2.05rem;
  background: var(--m-timeline-accent);
  transform: translateY(-0.18rem);

  box-shadow:
    0 0 0 0.42rem rgba(139, 30, 30, 0.09),
    0 0.8rem 1.75rem rgba(139, 30, 30, 0.18);
}

.m-timeline__card {
  min-height: 260px;
  height: 100%;
  padding: clamp(1.25rem, 2.5vw, 2rem);
  background: var(--m-timeline-card);
  border: 1px solid var(--m-timeline-border);
  box-shadow: none;

  transition:
    box-shadow 260ms ease,
    border-color 260ms ease,
    transform 260ms ease;
}

.m-timeline__item.is-active .m-timeline__card {
  border-color: color-mix(
    in srgb,
    var(--m-timeline-accent),
    var(--m-timeline-border) 72%
  );
  box-shadow: var(--m-timeline-shadow);
}

.m-timeline__card time:not(.sr-only) {
  position: absolute;
  width: 1px;
  height: 1px;
  overflow: hidden;
  clip-path: inset(50%);
  white-space: nowrap;
}

.m-timeline__card h3 {
  margin: 0 0 1rem;
  font-size: clamp(1.5rem, 2.6vw, 2.35rem);
  line-height: 1.05;
  font-weight: 400;
  letter-spacing: -0.025em;
}

.m-timeline__card p {
  margin: 0;
  color: var(--m-timeline-muted);
  font-size: 1rem;
  line-height: 1.65;
}

@media (hover: hover) {
  .m-timeline__item:hover {
    opacity: 1;
  }

  .m-timeline__item:hover::before {
    color: var(--m-timeline-text);
    border-color: rgba(43, 43, 43, 0.16);
  }

  .m-timeline__item:hover .m-timeline__card {
    transform: translateY(-3px);
    box-shadow: var(--m-timeline-shadow);
  }
}

@media (max-width: 600px) {
  .m-timeline {
    --m-timeline-card-width: 82vw;
    --m-timeline-gap: 1rem;

    padding: clamp(1.25rem, 5vw, 1.5rem) 0;
    margin-top: 2rem;
    margin-bottom: 2rem;
  }

  .m-timeline__controls {
    margin-bottom: 0.875rem;
  }

  .m-timeline__controls button {
    width: 2.5rem;
    height: 2.5rem;
    font-size: 1.75rem;
  }

  .m-timeline__track {
    padding-top: clamp(4.75rem, 18vw, 6.25rem);
  }

  .m-timeline__track::before,
  .m-timeline__track::after {
    top: clamp(2.95rem, 11vw, 3.8rem);
  }

  .m-timeline__item::before {
    bottom: calc(100% + 2rem);
    height: 1.9rem;
    min-width: 4rem;
    font-size: 0.78rem;
  }

  .m-timeline__item.is-active::before {
    min-width: 5rem;
    transform: translateY(-0.1rem) scale(1.05);
  }

  .m-timeline__item::after {
    bottom: calc(100% + 0.72rem);
  }

  .m-timeline__card {
    min-height: 240px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .m-timeline__controls button,
  .m-timeline__item,
  .m-timeline__item::before,
  .m-timeline__item::after,
  .m-timeline__card {
    transition: none;
  }

  .m-timeline__track {
    scroll-behavior: auto;
  }
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  overflow: hidden;
  clip-path: inset(50%);
  white-space: nowrap;
}