/* ── Architecture diagram ── */
  .arch-wrapper {
    display: flex;
    gap: var(--sp-4);
    justify-content: center;
    align-items: stretch;
    margin-top: var(--sp-3);
  }

  .arch-col {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: flex-end;
  }

  .arch-stack {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0;
  }

  .arch-box {
    padding: var(--sp-2) var(--sp-4);
    border-radius: var(--radius-sm);
    font-size: var(--fs-xs);
    font-weight: 600;
    text-align: center;
    min-width: 10rem;
    border: 1.5px solid;
    position: relative;
    z-index: 1;
  }

  .arch-box.embed   { background: rgba(160,80,0,0.12);  border-color: rgba(160,80,0,0.4);  color: var(--orange); }
  .arch-box.pos     { background: var(--yellow-bg);        border-color: var(--yellow-border);   color: var(--yellow); }
  .arch-box.drop    { background: rgba(61,69,112,0.08); border-color: rgba(61,69,112,0.55); color: var(--text-dim); }
  .arch-box.block   { background: var(--purple-bg);        border-color: var(--purple-border);   color: var(--purple); }
  .arch-box.norm    { background: var(--cyan-bg);           border-color: var(--cyan-border);     color: var(--cyan); }
  .arch-box.linear  { background: var(--accent-bg);         border-color: var(--accent-border);   color: var(--accent); }
  .arch-box.softmax { background: var(--green-bg);          border-color: var(--green-border);    color: var(--green); }
  .arch-box.attn    { background: rgba(90,48,200,0.15); border-color: rgba(90,48,200,0.45); color: var(--purple); }
  .arch-box.ffn     { background: var(--cyan-bg);           border-color: var(--cyan-border);     color: var(--cyan); }

  .arch-arrow {
    position: relative;
    width: 0.9rem;
    height: var(--arch-arrow-length);
    margin: 0.05rem 0;
    display: block;
    color: transparent;
    user-select: none;
    overflow: visible;
  }
  .arch-arrow::before {
    content: '';
    position: absolute;
    left: 50%;
    top: 0.26rem;
    bottom: 0;
    width: 1.5px;
    transform: translateX(-50%);
    background: rgba(61,69,112,0.85);
  }
  .arch-arrow::after {
    content: '';
    position: absolute;
    left: 50%;
    top: 0;
    width: 0.32rem;
    height: 0.32rem;
    border-left: 2px solid rgba(61,69,112,0.85);
    border-top: 2px solid rgba(61,69,112,0.85);
    transform: translateX(-50%) rotate(45deg);
  }

  .arch-label {
    font-size: var(--fs-2xs);
    color: var(--text-dim);
    margin-top: 0.1rem;
    margin-bottom: 0.1rem;
    font-style: italic;
  }

  .arch-plus {
    width: 1.3rem;
    height: 1.3rem;
    min-width: 1.3rem;
    min-height: 1.3rem;
    flex: 0 0 1.3rem;
    aspect-ratio: 1 / 1;
    border-radius: 50%;
    border: 1.5px solid var(--border);
    background: var(--surface2);
    display: flex;
    align-items: center;
    justify-content: center;
    line-height: 1;
    font-size: var(--fs-xs);
    font-weight: 700;
    color: var(--text-dim);
    margin: 0.1rem 0;
    z-index: 1;
  }

  .arch-brace {
    border: 1.5px dashed var(--purple-border);
    border-radius: var(--radius-md);
    padding: 0.6rem 0.85rem;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0;
    position: relative;
  }

  .arch-brace-label {
    position: absolute;
    right: -0.5rem;
    top: 50%;
    transform: translateY(-50%) translateX(100%);
    font-size: var(--fs-2xs);
    color: var(--text-dim);
    white-space: nowrap;
    padding-left: var(--sp-2);
  }

  .arch-dots {
    font-size: var(--fs-sm);
    color: var(--text-dim);
    letter-spacing: 0.15em;
    padding: 0.05rem 0;
  }

  /* Positional encoding side-entry into + */
  .pos-merge {
    position: relative;
    display: flex;
    align-items: center;
    justify-content: center;
    width: 0;
  }
  .pos-merge .arch-box.pos {
    position: absolute;
    top: 50%;
    right: calc(100% + 1.6rem);
    transform: translateY(-50%);
    min-width: auto;
    padding: 0.35rem 0.6rem;
    font-size: var(--fs-2xs);
    white-space: nowrap;
  }
  .pos-side-arrow {
    position: absolute;
    top: 50%;
    right: calc(100% + 0.7rem);
    transform: translateY(-50%);
    width: 0.9rem;
    height: 0.5rem;
    color: transparent;
    font-size: 0;
    line-height: 0;
    padding: 0;
    display: block;
    pointer-events: none;
  }
  .pos-side-arrow::before {
    content: '';
    position: absolute;
    left: 0;
    right: 0.22rem;
    top: 50%;
    height: 1.5px;
    transform: translateY(-50%);
    background: rgba(61,69,112,0.85);
  }
  .pos-side-arrow::after {
    content: '';
    position: absolute;
    right: 0;
    top: 50%;
    width: 0.28rem;
    height: 0.28rem;
    border-top: 2px solid rgba(61,69,112,0.85);
    border-right: 2px solid rgba(61,69,112,0.85);
    transform: translateY(-50%) rotate(45deg);
  }

  /* Zoom-in panel for block detail */
  .block-detail-panel {
    background: rgba(90,48,200,0.06);
    border: 1.5px solid rgba(90,48,200,0.2);
    border-radius: var(--radius-lg);
    padding: var(--sp-3) var(--sp-4);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: flex-end;
    position: relative;
    margin-left: 3.2rem;
    opacity: 1;
    align-self: center;
    height: max-content;
    min-width: 14.6rem;
    transform: translateY(-1rem);
  }
  .block-detail-title {
    position: absolute;
    top: 0.42rem;
    left: 50%;
    transform: translateX(-50%);
    font-size: var(--fs-2xs);
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    color: var(--purple);
    opacity: 0.7;
    white-space: nowrap;
  }
  .block-detail-panel .arch-stack {
    margin-top: var(--sp-2) !important;
  }
  .block-detail-panel .arch-label {
    font-size: var(--fs-2xs);
  }
  .block-detail-panel .arch-box {
    min-width: 7.5rem;
    padding: 0.3rem 0.7rem;
    font-size: var(--fs-2xs);
  }
  .block-detail-panel .arch-box.drop,
  .block-detail-panel .arch-box.norm {
    min-width: 6.5rem !important;
  }
  .block-detail-panel .arch-arrow {
    width: 0.75rem;
    height: var(--arch-arrow-length-detail);
    margin: 0;
  }
  .block-detail-panel .arch-plus {
    width: 1rem;
    height: 1rem;
    min-width: 1rem;
    min-height: 1rem;
    flex-basis: 1rem;
    font-size: var(--fs-2xs);
  }
  .block-detail-panel .residual-group {
    padding-right: 0;
  }
  .block-detail-panel .residual-group .bypass {
    left: auto;
    right: -1.05rem;
    top: 0.66rem;
    bottom: -0.78rem;
    width: calc(50% + 0.55rem);
  }
  .block-detail-panel .residual-group .bypass::before {
    left: 0;
    right: 0;
    top: 0;
    bottom: 0;
    width: auto;
    border-right: 1.5px solid rgba(61,69,112,0.35);
    border-top: 1.5px solid rgba(61,69,112,0.35);
    border-bottom: 1.5px solid rgba(61,69,112,0.35);
    border-left: none;
    border-radius: 0 0.28rem 0.28rem 0;
  }
  .block-detail-panel .residual-group .bypass::after {
    content: '';
    position: absolute;
    left: 0;
    right: auto;
    top: 0;
    width: 0;
    height: 0;
    border-top: 0.17rem solid transparent;
    border-bottom: 0.17rem solid transparent;
    border-right: 0.26rem solid rgba(61,69,112,0.75);
    border-left: none;
    transform: translate(-0.02rem, -40%) !important;
    z-index: 2;
  }

  /* Projector-safe compaction for slide 3 */
  #slide-3 h2 {
    margin-bottom: 0.0rem;
  }

  #slide-3 .spacer-sm {
    height: 0.0rem;
  }

  #slide-3 .arch-wrapper {
    gap: 3rem;
    margin-top: 0.00rem;
    align-items: flex-start;
  }

  #slide-3 .arch-box {
    min-width: 9.8rem;
    padding: 0.3rem 0.82rem;
    font-size: 0.74rem;
  }

  #slide-3 .arch-label {
    font-size: 0.58rem;
    margin: 0;
  }

  #slide-3 .arch-arrow {
    width: 0.8rem;
    height: 0.96rem;
    margin: 0;
  }

  #slide-3 .arch-arrow::before {
    top: 0.2rem;
  }

  #slide-3 .arch-arrow::after {
    width: 0.26rem;
    height: 0.26rem;
  }

  #slide-3 .arch-plus {
    width: 1.04rem;
    height: 1.04rem;
    min-width: 1.04rem;
    min-height: 1.04rem;
    flex: 0 0 1.04rem;
    font-size: 0.6rem;
    margin: 0.05rem 0;
  }

  #slide-3 .arch-brace {
    padding: 0.5rem 0.68rem;
  }

  #slide-3 .arch-brace-label {
    right: -0.42rem;
    font-size: 0.6rem;
  }

  #slide-3 .arch-dots {
    font-size: 0.78rem;
    padding: 0;
  }

  #slide-3 .pos-merge .arch-box.pos {
    right: calc(100% + 1.45rem);
    padding: 0.26rem 0.5rem;
    font-size: 0.58rem;
  }

  #slide-3 .pos-side-arrow {
    right: calc(100% + 0.62rem);
    width: 0.82rem;
  }

  #slide-3 .block-detail-panel {
    margin-left: 2.35rem;
    padding: 0.8rem 0.96rem;
    min-width: 13.6rem;
    transform: translateY(-0.35rem);
  }

  #slide-3 .block-detail-title {
    top: 0.34rem;
    font-size: 0.56rem;
  }

  #slide-3 .block-detail-panel .arch-stack {
    margin-top: 0.7rem !important;
  }

  #slide-3 .block-detail-panel .arch-box {
    min-width: 6.6rem;
    padding: 0.24rem 0.54rem;
    font-size: 0.6rem;
  }

  #slide-3 .block-detail-panel .arch-box.drop,
  #slide-3 .block-detail-panel .arch-box.norm {
    min-width: 5.8rem !important;
  }

  #slide-3 .block-detail-panel .arch-arrow {
    height: 0.76rem;
  }

  #slide-3 .block-detail-panel .arch-plus {
    width: 0.92rem;
    height: 0.92rem;
    min-width: 0.92rem;
    min-height: 0.92rem;
    flex-basis: 0.92rem;
    font-size: 0.56rem;
  }

  #slide-3 .block-detail-panel .residual-group .bypass {
    right: -0.92rem;
    top: 0.58rem;
    bottom: -0.62rem;
    width: calc(50% + 0.46rem);
  }

  #slide-3 > .callout.info {
    max-width: 38rem;
    padding: 0.56rem 0.8rem;
    font-size: var(--fs-xs);
    line-height: 1.42;
  }

  #slide-3 > .callout.info .icon {
    font-size: var(--fs-base);
  }

  /* Residual bypass arrow */
  .residual-group {
    position: relative;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0;
    padding-right: 2rem;
  }
  .residual-group .bypass {
    position: absolute;
    right: 0;
    top: 0;
    bottom: 0;
    width: 1.6rem;
    pointer-events: none;
  }
  .residual-group .bypass::before {
    content: '';
    position: absolute;
    right: 0.15rem;
    top: 0.65rem;
    bottom: 0.65rem;
    width: 1rem;
    border: 1.5px solid rgba(61,69,112,0.35);
    border-left: none;
    border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  }
  /* top horizontal tick into the + */
  .residual-group .bypass::after {
    content: '\2192';
    position: absolute;
    right: 0.85rem;
    top: 0.15rem;
    font-size: var(--fs-2xs);
    color: rgba(61,69,112,0.5);
    transform: rotate(180deg);
  }

  /* ── Tokenization visuals ── */
  .token-anchor {
    font-size: var(--fs-lg);
    line-height: 1.5;
    color: #0d1020;
  }
  .token-anchor strong {
    color: var(--accent);
    font-weight: 700;
  }
  .token-interface {
    display: flex;
    align-items: center;
  }